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May 1981 Communications

ESAO EUROPEAN SOCIETY FOR ARTIFICIAL ORGANS

ABSTRACTS 8th ANNUAL MEETING

1981

24-26 AUGUST COPENHAGEN

DENMARK

Abstracts Notice 0 above title indicates slide session.

0 0 above title indicates graphic session. Proceedings

The Proceedings of the 1981 Meeting will be available in September a t a price of Swiss Fr.50. Please send purchase enquiries to:

ESAO Secretariat Dr. J . Belenger 10, route des Jeunes 1227 Geneva-La Praille Switzerland

President: I. H. Rygg SecretarylTreasurer: J. Belenger B. Bellhouse *4ssistant Secretary: C. J. Knight

Selection Committee: Ch. Hahn

A. Carpentier J. L. Funck-Brentano Ch. Mion M. Schaldach M. Turina

183

Artificial Organs

GLUCOSE CONTROL DURING HEMODIALYSIS OF DIABETIC Title: PATIENTS

AaP Hansen, H. Orskov, HE Hansen, 0. Schmitz v . Posborg, KGMM A l b e r t i . F i r s t and Second U n i v e r s i t y C l i n i c of I n t e r n a l Medicine, Kommunehospitalet, Aarhus, Denmark. De-

upon Tyne. UK.

U n s a t i s f a c t o r y b lood g lucose (and e l e c t r o l y t e and hemo. dynamic] c o n t r o l d u r i n g and a f t e r h e n o d i a l y s i s is c , f t en encoun te red i n uremic d i a b e t i c p a t i e n t s and s e r i o u s - l y adds t o t h e i r d i s c o m f o r t and s u s c e p t i b i l i t y t o v a s c u l a r and i n f e c t i o u s c o m p l i c a t i o n s . plasma g l u c o s e , i n s u l i n , p a n c r e a t i c glucagon, growth hor- mone and m e t a b o l i t e s were measured b e f o r e , du r ing and a f - t e r hemodia lys i s i n ha l f -hour samples o b t a i n e d d u r i n g 61 d i a l y s e s .

1 . Severe and p ro longed hypoglycemia was o f t e n encounte- r e d when d i a l y s i s t ook p l a c e a g a i n s t g l u c o s e f r e e medium. _. 2 . D i a l y s i s a g a i n s t g l u c o s e c o n t a i n i n g d i a l y s i s f l u i d w a s s o l e l y s a t i s f a c t o r y i n p a t i e n t s who were normoglycemic a t t h e i n i t i a t i o n o f d i a l y s i s . 2. A s i m p l e s c h e d u l e of glucose i n f u s i o n depending a n hour ly b lood g l u c o s e d e t e n i n a - t i o n s was c o n t r u c t e d o n t h e b a s i s o f d a t a o f t h e a r t i f i c i - a l p a n c r e a s ' ( B i o s t a t o r ) d e l i v e r y o f i n s u l i n and g l u c o s e . When t h i s p r o t o c o l w a s u t i l i z e d b lood g l u c o s e and e l e c t r o - l y t e c o n t r o l approached t h o s e o b t a i n e d w l t h t h e B ios t a to r , , and were f a r b e t t e r t h a n d u r i n g and a f t e r d i a l y s i s a g a i n s t q lucose c o n t a i n i n g f l u i d .

conc lus ion : A ve ry s imple p r o t o c o l of g l u c o s e i n f u s i o n depending on hour ly blood g l u c o s e d e t e r m i n a t i o n s is p r e s e n t e d , which e n s u r e s e x c e l l e n t g l u c o s e c o n t r o l du r ing and a f t e r hemo- d i a l y s i s i n d i a b e t i c p a t i e n t s .

R e s u l t s : -

a a Evaluat ion o f a glucose sensor u t i l i z i n g e l e c t r o - o p t i c a l techniques

Z e n t r a l i n s t i t u t f u r Biomed. Technik Uni. ERLANGEN, 0-8520 Erlangen, Turnstr . 5

Author(s): P. Baurschmidt and M. Schaldach

Addre=:

arawbacks i n the deve lopwnt o f long-term s tab le and se lec t ive glucose sensors have come up fo r bo th systems i n discussion: the enzymatic and the electrochemical system. Improved r e s u l t s under the requirements o f i m p l a n t a b i l i t y a re thought t o be best achieved by e l e c t r o c a t a l y t i c a l methods. The e lec t ro -ox ida t ion and reduc t ion o f glucose and o f i n t e r f e r i n g coreactants have been s tud ied by spectro- electrochemical techniques, thus g i v i n g a c lose corre- l a t i o n between ox ida t ion reac t ions and the bui ldup and s t r u c t u r a l composition o f oxide layers o f vary ing metal e lectrodes. Up t o now, on ly assumptions as t o the in f luence o f urea, p ro te ins and amino acids upon the bachground cur ren ts and i n t e r f a c i a l impedance had been possible. The r e s u l t s deduced from noble metal e lectrodes show t h a t ox ida t ion processes and adsorbt ion from reac t ion products reduce the oxide l a y e r r e l a t e d cur ren ts by m r e than a fac to r o f 3. Under o p t i c a l sur face cont ro l appropr iate p o l a r i s a t i o n cycles f o r the mode o f re juvenat ing, measuring and stand-by have been found, lead ing t o an increase i n s t a b i l i t y and s e l c t i v i t y w i t h an o v e r a l l i n t e r f e r i n g o f less than 20%.

~ i t l ~ : Development o f a tubing-system t o f a c i l i t a t e i n j e c t i o n

Author@). Bottermann,P., Gyaram, H.

Address: I I. fled. C1 i n i c ,Technical U n i v e r s i t y , Muni ch

o f i n s u l i n i n t r a p e r i t o n e a l .

I n a previous study l e d by us, we examined the pharmaco- k i n e t i c s o f r e g u l a r i n s u l i n administered i n t r a p e r i t o n e a l i n a bolus form i n f i v e normal non-diabet ic volunteers. The plasm-ulin concent ra t ion i n the per iphera l vascular system a f t e r a carbohydrate s t i m u l a t i o n t e s t and s.c.appli- c a t i o n o f i n s u l i n were furthermore considered f o r comparison. It was observed t h a t t h e behaviour o f i n s u l i n concen- t r a t i o n i n per iphera l b lood a f t e r i .p . in jec t ion cor re la ted b e t t e r t o normal E-ce l l secre t ion a f t e r a carbohydrate- enriched meal than a f t e r convent ional s . ~ . app l i ca t ion .

Therefore, t o f a c i l i t a t e the i n j e c t i o n o f i n s u l i n i n t r a - per i tonea l d a i l y , we have developed an implantable tubinq- system which connects the i n t r a p e r i t o n e a l c a v i t y t o the subcutaneous t i ssue. The tubing-system i s made from s i l i c o n e rubber, the same m a t e r i a l used i n per i tonea l d i a l y s i s ca the ter . Our t e s t f o r t i s s u e tolerance i n f o u r p igs proves t o be s a t i s f a c t o r y and r e l i a b l e f o r f u t u r e imp lan ta t ion i n human beings.

a a A c o r r e l a t i o n of the g l u c o s e modulat ion index w i t h

Title: d i f f e r e n t r o u t e s o f i n s u l i n a d m i n i s t r a t i o n .

Author(s): W. Zingg, J. M . Smith, J . H. S h i r r i f f , and B. S.

Address: Research I n s t i t u t e , H o s p i t a l f o r S i ck C h i l d r e n , 555 U n i v e r s i t y Avenue, Toron to , Ont. Canada. HSG 1x8

P h y s i o l o g i c a l a s ses smen t of t h e v a r i o u s r o u t e s of i n s u l i n d e l i v e r y is n e c e s s a r y f o r t h e most a p p r o p r i a t e use of pan- c r e a t i c t r a n s p l a n t s and mechan ica l d e v i c e s . I n a normal animal model, t h e r e s p e c t i v e a b s o r p t i o n p a t t e r n s and c o r r e s - ponding g l u c o s e r e sponses were s t u d i e d q u a n t i t a t i v e l y and s imul t aneous ly i n t h e p o r t a l and p e r i p h e r a l venous systems and i n t h e t h o r a c i c duc t . S i x r o u t e s of d e l i v e r y were s t u d i e d : i n t r a p o r t a l (IVPO), p e r i p h e r a l i n t r avenous (IVPE), i n t r a p e r i t o n e a l ( I P ) , e x t r a p e r i t o n e a l ( E P ) , subcu taneous ab- domen (SCA), subcu taneous l e g (SCL). P a r a m e t r i c or nonpara- m e t r i c s ta t i s t ica l a n a l y s e s of v a r i a n c e were used t o d e t e r - mine s i g n i f i c a n t d i f f e r e n c e s .

and modulat ion of g lucose r e sponse . IVPO dosage had t o be reduced 40% t o avo id hypoglycemia and dea th . Modulation of g l u c o s e r e sponse was e x c e l l e n t . Absorp t ion o f i n s u l i n i n t o lymph was r a p i d , s u s t a i n e d and exceeded blood c o n c e n t r a t i o n . I P shoved s u s t a i n e d lymph c o n c e n t r a t i o n , w i th p o r t a l absorp- t i o n and g l u c o s e modu la t ion somewhat less t h a n SCA. IVPE r e s u l t e d i n t h e p o o r e s t g l u c o s e modu la t ion w i t h a marked tendency t o hypoglycemia. T h i s was a s s o c i a t e d wi th t h e most r a p i d peak ing and d e c l i n e of p o r t a l i n s u l i n . A mathematical e x p r e s s i o n c a l l e d t h e g l u c o s e modu la t ion i n d e x (GMI) has been developed which e n a b l e s a compara t ive i n t e r p r e t a t i o n of t h e g lucose r e sponse c u r v e s f o r each r o u t e of i n s u l i n d e l i v e r y .

a s IVPE i n s u l i n and i n a d d i t i o n r e s u l t s i n much b e t t e r g lucose modu la t ion . ( 2 ) SCA and I P show e x c e l l e n t modulat ion wi th SCA b e i n g the least c l i n i c a l l y i n v a s i v e . (3) IVPE has t h e p o o r e s t g l u c o s e modu la t ion and might w e l l be r e se rved f o r c losed loop sys t ems . (4) The GMI prov ided a q u a n t i r a r i v e corn- p a r i s o n of g l u c o s e r e sponse t o i n s u l i n a d m i n i s t r a t i o n .

L e i b e l .

Each r o u t e h a s i ts own r e p r o d u c i b l e p a t t e r n of a b s o r p t i o n

Conclusions: (1) IVPO i n s u l i n is abou t twice as e f f e c t i v e

184


Title: EXTRACORPOREAL BLOOD FLOWMETER AND CONTROLLER

Author(s): 3. Hruska

Address: S c i e n c e , Pa rks Road, Oxford. United Kingdom Oxford U n i v e r s i t y , Department of Eng inee r ing

Ex t raco rporea l measurement of blood f low i s one of t h e problems encoun te red d u r i n g c l i n i c a l haemodia lys i s . A new system r e q u i r i n g no c a l i b r a t i o n b e f o r e u s e and us ing cheap, d i s p o s a b l e p robes h a s been designed i n answer t o t h i s problem.

The sys t em i s in t ended t o be used f o r t he measurement and c o n t r o l o f l amina r , p u l s a t i n g blood f low i n t h e range 150 - 500 ml/min i n s i d e a p l a s t i c tube of 5 . 5 mm bore a s used i n h a e m o c i a l y s i s . It u t i l i s e s the thermal p u l s e , t ime of f l i g h t t echn ique . upstream h e a t e r t o produce a b o l u s wi th a t empera tu re h i g h e r by approx ima te ly taken f o r t h i s bo lus LO r each a t h e r m i s t o r probe placed downstream is then measured and , from t h i s , v o l u m e t r i c f low is computed by s t r a i g h t l i n e i n t e r p o l a t i o n from a c a l i b r a t i o n t a b l e . An e r r o r s i g n a l is c a l c u l a t e d by comparing t h i s f l ow wi th the f low r e q u i r e d and a c o r r e c t i o n then a p p l i e d t o an e l e c t r i c a l l y c o n t r o l l e d b lood pump. This e n t i r e o p e r a t i o n i s c a r r i e d out under mic roprocesso r c o n t r o l .

The accu racy throughou't t he r ange of t h e f lowmeter i s b e t t e r t h a n 41 d e v i a t i o n from t r u e vo lumet r i c f low and t h e maximum r a t e i-t which the measurements can be made is 4 p e r minute .

Blood i s f i r s t b r i e f l y warmed by an

K t h a n t h e r e s t of t he b lood . The t i m e

0

7itle: Physic .31 a n d b i o c h e m i c a l c h a r a c t e r i z a t i o n o f b i o m a t e r i a l ; w i t h r e s p e c t t o b l o o d c o m p a t i b i l i t y Aulhor(s): J . P . F i s c h e r * , K . Burg* , P. Fuhge**,

N. Heimburger** Address- * HOECHST AG, D-6230 Frankfu r t /M. 80

* * Behr ingwerke A G , D - 3 5 5 0 Marburq/Lahn Tubing o f d i f f e r e n t i n t e r n a l d i a m e t e r ( I D ) were p r e p a r e d from 10 d i f f e r e n t po lymers (CPE, EPDM, ETFE, EVA, LDPE, PP, PTFE, P U R , PVC a n d S i l i c o n e ) :

a ) t u b i n g of 4-5 mm I D f o r i n v i t r o - a n d e x v i v o - b l o o d c o m p a t i b i l i t y t e s t s w i t h human b l o o d

b ) t u b i n g of 0.3-0.4 mm I D f o r e x v ivo - e v a l u a - t i o n s f o r b l o o d c o m p a t i b i l i t y v i a measu r ing t h e b l e e d i n q t i m e a f t e r i n t r o d u c t i o n of t h e t u b i n g i n t o t h e ear v e i n o f r a b b i t s .

The t u b i n g w e r e s u r f a c e m o d i f i e d by g r a f t i n g w i t h N-vinyl-N-methyl a c e t a m i d e (VIMA).

For b o t h t h e o r i g i n a l a n d t h e g r a f t e d t u b i n g c o r - r e l a t i o n s were e s t a b l i s h e d be tween t h e p h v s i c a l c h a r a c t e r i z a t i o n ( d e g r e e o f g r a f t i n g , c r i t i c a l s u r f a c e t e n s i o n , ESCA, FT-ATR, SEMI and t h e 2 v i t r o a n d t h e ex v i v o b l o o d C o m p a t i b i l i t y t es t s . The i n v i t r o b l o o d c o m p a t i b i l i t y t e s t s c o n s i s t of an i n c u b a t i o n of 4-5 m t u b i n g w i t h c i t r a t e d human b l o o Z and s u b s e q u e n t d e t e r m i n a t i o n s o f c l o t - t i n g paramet .ers . I n a d d i t i o n S E M - i n v e s t i g a t i o n s of t h e t reated s u r f a c e w e r e pe r fo rmed . The human e x v i v o b l o o d c o m p a t i b i l i t y t e s t s were pe r fo rmed on human arm v e i n s f o l l o w e d by i n v e s t i - g a t i o n o f t h e i n t e r n a l s u r f a c e of t h e t u b i n g (SEM, p l a t e l e t and f i b r i n o g e n d e p o s i t i o n ) . The r e s u l t s c o u l d b e c o i : r e l a t e d w i t h t h e i n v i t r o t e s t s w i t h human b l o o d . A compariso;i w i t h c o n v e n t i o n a l t u b i n g on t h e m a r - k e t (PVC and S i l i c o n e ) as a s t a n d a r d shows , t h a t PTFE/VIMA, I,IlPE/VIMA, PUR and EVA have better b lood c o m p a t j l i l i t y p r o p e r t i e s t h a n t h e s t a n d a r d whereas u n t r e a t e d PTFE and LDPE a r e r a n k e d below t h e s t a n d a r d . Sponsored bl' BMFT, Bonn (MSO 1191

T h e u s e of A12 0 3 to i n c r e a s e the life of a hip

Comparative endurance test on both metal and ce ramic mat er I a is

Title: endoprosthesis

Au'hor(s): Pr. San to r i , Clinica Ortopedica Univ. Roma I Dr. Ing. Sandroi ini C o r t e s i , Sarno, Bologna I Dr. Gambini, Clinica Or toped ica Univ. Roma I

Though "pin on d i sc" t e s l s the Authors have examined the modifications by different ma te r i a l s (disc of T i , Inox, A12 03) into contact with a r t i cu la r ca r t i l age and sclerotic subcondral bone t issue. T h e examination of the behaviour of c a r t i l a g e , has evidenced a wide da te sca t t e r ing determined by the different s enescence s t a t e of samples used. However, A12 0 3 coupling has given r e s u l t s more enduring in the long run. T e s t s on subcondral s c l e ro t i c bone t i s sue have shown that a re levant roughness of metal s u r f a c e formed, what speeded up the wea r p r o c e s s by bone t issue. T h e ceramic s u r f a c e has presented, on the con t r a ry , no a l t e r a t ions and consequent11 a s lower wear p r o c e s s by bone t issue. F u r t h e r to these r e s u l t s , some endoprosthesis (by f r a c t u r e s of femur neck) with s i n t e r e d A12 O3 ball have been implanted. Clinical r e s u l t s c a r r i e d out 3 y e a r s l a t e r follow a posi t ive course.

0 . F i R S T CONSIDERATIONS ON THE USE OF ZrOZ IN HIP PROSTHESIS STEM COATING

Pr.Monticel l i , Ci inica Ortopedica Univ. Romal

D r . Ing. S. Sandrol ini Cor t e s i , Samo, Bologna I M. Sandrol ini Cor t e s i , Bologna I

Title:

Author(s): Pr. San to r i , Clinica Ortopedica Univ. Roma I

Address :

T o posit ively contr ibute to the r e s e a r c h of implant maler ia ls actually biocompatible and functionally long lasting, var ious possibi l i t ies have been examined in order to set up a hip p ros thes i s with ce ramic coated metal stem. T o coat a t a high temperature i t ha s been used Plasma S p r a y . In 1973 the first clinical experiences made in Italy brought, a f t e r careful l evaluation from both a biological and functional s tand point, to the u s e of Allumina coating. F u r t h e r examinations of such expe r i ences induced the Authors to u s e the Z r O a s a subs t i t u t e of Al 0

T h e var ious methodologies applied have shown a higher re l iabi i i ty of Z r 0 Exams o n biocomp$tibility c a r r i e d out using metal samples coated with the mentioned material has given posi t ive r e su l t s . T h e implanlation of these samples into bone t issue of animals ( sheeps ) has not shown any t i s sue react ion and evidenced a vital bone t i s sue growth to c lose touch with ceramic. T h e f i r s t "in c o r p o r e vir i" implantation follow posit ive c o u r s e and, a s a consequence, encourage to go ahed.

2 2 3'

in i t s adhesion to the metal.

185

Artificial Organs 0

Vol. 5, No. 2

C h a r a c t e r i z a t i o n o f p r o t e i n a d s o r p t i o n l a y e r s

H.J.SCHUUE+'. H.WOLF, A n e t t e TROMMLER

Dept . o f M e d i c i n e I C h a r i t e ' ) o f Hpmboldt-

Titleby means o f t h e s t a b i l i t y o f t h i n l i q u i d f i l m s

AuthOW

Address: u n i v a r e i t y , 104 B e r l i n , GDR.

I t woe t h e a im o f t h i s s t u d y t o g e t f u r t h e r i n f o r - m a t i o n abou t t h e m o l e c u l a r o r g a n i z a t i o n o f p r o t e i n mo lecu lee adso rbed a t i n t e r f a c e s by a d a p t i o n o f a c o l l o i d - c h e m i c a l method f o r i n v e s t i g a t i o n o f t h i n l i q u i d f i l m e . I n t h e eyetem q u a r t z / e l e c t r o l y t e / a l r t h e s t a b i l i t y and t h i c k n e e e o f th in l i q u i d f i l r n a were i n v e s t i g a - ted , wh ich a n formed by human s e r u m albumin solu- t i o n e i n dependence on p r o t e i n c o n c e n t r a t i o n , pH and i o n i c s t r e n g t h . I t was found t h a t p r o t e i n c o n c e n t r a t i o n e h i g h e r t h a n 10-6 molee/dm-3 p roduce s t a b l e l i q u i d f i l m e w i t h a t h i c k n e e e between 10 nm end 45 nm i n dependence on i o n i c s t r e n g t h , pH and p r o e i n concen t ra - t i o n . A t an i o n i c s t r e n g t h o f 5xlC~'%nolee/dm'~ t h e f i l m t h l c k n e e e reachee a maximum o f 45 nm. I n a l l caees t h e t h i c k n e s s o f f i l m e was much h i g h e r t h a n t h a t h e o r e t l c a l c a l c u l a t e d va luee f o r p u r e e l e c t r o - l y t e f i l m e due t o t h e a l e c t r o e t a t i c i n t e r a c t i o n o f t h e e l e c t r i c a l d o u b l e l a y e r e a t t h e s o l i d / a l e c t r o - l y r e and e l e c t r o l y t e / a i r i n t e r f e c e e . From theea re - s u l t e i t c o u l d be conc ludnd t h a t i n t h e human serum a l b u m i n e o l u t i o n e an a d s o r p t i o n o f p r o t e i n a t t h e two I n t e r f a c e . t o o k p l a c e accompanied by a p a r t i a l u n f o l d i n g o f t h e adeorbed p r o t e i n mo lecu lee . The i n c r e a s e o f f i l m t h i c k n e s s eeeme t o be a measure f o r t h e e x t e n t o f c o n f o r m a t i o n a l changea ef t h e adso rbed p r o t e i n mo lecu les . The method p r e s e n t e d h e r e o f f e r s a new p o s s i b i l i t y t o i n v e s t i g a t e t h e i n f l u e n c e o f d i f f e r e n t b lomate- r i a l s on t h e c o n f o r m a t i o n o f plasma p r o t e i n s bed t o t h e m a t e r i a l / e l e c t r o l y t e i n t e r f a c e .

+ FIA, Academy O f Sc iences o f GOR. 92 F r e i b e r g

0 THE BIOCOKFATIBILI'IY OF THE CUPROPHAN

Wlodzimierz Zabo j s a c a , ICacie j Zbororvski.

Inst. of Biocybernetics and Biomedical Engineering P.A.s., Warsaw, Poland.

Title: HXBRANE WITH THE COBALT CATALYST.

A'Jthor(s):Inst. for D m g Research and Control,

The Cuprophan membrane activated with the oxide of a heavy metal, in the pre - sence o f the hydrogen -peroxide,was considered as a possible source o f oxycen in the extracorporeal membrane oxygenation of blood.The catalyst was deposited in the membrane in the form of the insoluble pre- cipitate of the cobalt oxide COO, .The biocompatibility of a large area (0.25 ma) of such a membrane was .tested in a series of experiments consistine; of: the toxicity tests on fishes, incubation of fibro- blasts on the membrane sarface,the determination of the level of free hemoglobin and cobalt compounds in the-human blood, the determination of protein fractions in the blood plasma, adhesion of the blood cellular elements to the membrane surface. An in vitro experimental setup consisted of a Nycotron dialyzer a n d of two roller pumps f o r the blood w d the dialysis bath channels each.The experiments lasted for 6 hours.The results show a good biocompatibility of the modified Cuprophan mem - brane and sugccest that it can be used n-ith out damage to the blood f o r several days.

0

Title: BIODEGRADATION OF SOME BIOYATERIALS AFTER

SUBCUTANEOUS IMPLANTATION. Author(s): I J . Lemm, T. Krukenberg, K. Gerlach, E. S . Biicherl

Address: Ch i ru rg . K l i n i k u. P o l i k l i n i k de r F r e i e n U n i v e r s i - t a t B e r l i n , Snandauer Damn 130, D-1000 B e r l i n 19

The loss of mechanical strength and changes in surface properties of polymeric materials in a bic- logical environment is defined as biodegradation. This effect can limit the usefulness of prosthe- tic devices: for example formerly smooth surfaces with excellent thromboresistance become rough and may cause thrombosis. The phenomena of biodegradation is not understood in details, but it is suggested that specialized cells, some enzymes and low molecular substances may destroy the polymeric structure. Samples of seven elastomeric materials (one polyester, one polyesterurethane, four polyether- urethanes and one synthr.tic rubber) were implanted subcutaneously in the back of rats up to nine months. After different times test specimens of each material were removed and changes in molecular weight and mechanical strength were tested. The genesis of surface ruptures and cracks were analy,zed by SEN.

Within two weeks the polyester was completely re- sorbed. Five materials lost between 20 and 40 % of their origin molecular weight, while mechanical properties were not influenced essentially. One polyetherurethane lost more than 50 % of its original tensile strength. SEM-analysis showdthat ruptures and cracks start at small surface defects but mainly in the area where the samples are slightly damaged, when they were cut out of films. The best material, the syn- thetic rubber had no surface ruptures, followed by Avcothane 5 1 , which additionally did not loose its average molecular weight and mechanical strength,

0 CALCIFICATION OF ARTIFICIAL HEART VALVES AND

Title : ARTIFICIAL HEARTS

Author(s): E. Henniq, H. Kei lbach, 0. Hoder', E.S. Bucherl

Address:

m l i n i k und t I n s t . f u r Pa tho log ie , K1 in ikum Charlot tenburg, F r e i e U n i v e r s i t a t B e r l i n , Spandauer Damn 130, 1000 B e r l i n 19

C a l c i f i e d deoos i t s were observed i n c e r t a i n reg ions o f a r t i f i c i a l b lood pumos and hear t valves a f t e r b lood e x p o s i t i o n pe r iods o f up t o 190 days. The calc ium- ohosohate and calc ium-carbonate c r y s t a l s a re o f t e n covered by o rgan ic depos i t s .

Even a f t e r ve ry s h o r t i m p l a n t a t i o n d u r a t i o n s o f l o days t h e f i r s t m ine ra l olaques c o u l d be de tec ted by EDAX-spot a n a l y s i s .

To analyse the o r i g i n o f t h e c a l c i f i c a t i o n , oneuma- t i c b lood pumps made o u t o f o e l l e t h a n e and t r i - l e a f l e t hea r t va l ves made o u t o f avcothane as w e l l as po rc ine xenograf ts were i n v e s t i g a t e d be fo re and a f t e r d i f f e - r e n t e x p o s i t i o n pe r iods i n animal exoer iments (microscopic, scanning e lec t ronmic roscop ic ' and energy- d i s p e r s i v e x - ray examinat ions - EDAX).

The s tudy suggested t h a t t he c a l c i f i c a t i o n occurs i n re? ions w i t h h i g h f l e x u r e where m ic roscoo ic su r face damage by the mechanical l o a d i s t h e o r i g i n o f t he de- o o s i t s . Secondary, these s t i f f depos i t s a r e causing f l e x i o n f a i l u r e , ab ras ion o f t he surface and r u p t u r e of t he oump membrane and v a l v e l e a f l e t s due t o i n - creased tension.

Obviously, su r face c r a c k s due t o h i n h f l e x i o n and o t h e r su r face i r r e g u l a r i t i e s a r e an impor tan t f a c t o r f o r thrombus format ion and m i n e r a l i z a t i o n .

186


A MODEL FOR THE E X A M I N A T I O N OF NONPOROUS PULMONARY AND AORTIC GRAFTS Title:

Author(s): L K r a u t z b e r g e r , C h . GroRe-Siestrup, K. Affeld, K. Gerlach, E . Hennig, H. Keilbach, E.S . Bucherl;

Address: K1 inikum Charlottenburg, Fre ie Universitat Berlin Spandauer Damm 130, 0-1000 Berlin 19

Inflow and outflow obstructions by excessive t i s sue nrowth i n the connectors f o r a r t i f i c i a l blood puros are well known comnlications.

In calves ( 7 0 k y ) , ( a f t e r left-side-thoracotomy under extracorqoredl c i rcu la t ion) oorous, nonqorous and com- cosed n ra f t s (30 mm lon?, 25 mm 0 ) were imolanted i n the oulmonary a r t e ry and in the thoracic aorta up t o 5 months.

The oro l i fe ra t ion of fibrous connective t i s sue and endo the l i a l4 ike membranes was observed in a l l animals and could be ver i f ied a l so anqioqraohically. However, subsequent scenosis occured mainly i n the Dulmonary c r a f t s (40 % of a l l animals). The spreading neointima in the a o r t i c g ra f t s was smooth, not more than 1 mm thick a n d adherent. No difference could be observed between these implants and the connectors f o r t he a r t i - f i c i a l blood pumos.

endothelial leasions. thrombotic and bac ter ia l in f luences , e l a s t i c i t y m.ismatch in the area of anastomosis and ooly- mer surface cha rac t e r i s t i c s . !Jith more experiments and d i f f e ren t materials i t should be Dossible t o know more about development and causes of t h i s t i s sue formation.

As causes fo r thes'e f indinos a re discussed:

Title: CHARACTERIZATION OF EXTRACORPOREAL SHUNTS POSSESSING SURFACE HEPARIN-LIKE PROPERTIES

Author(s): C. Fougnot, C. Baquey, A. Lautier, A. Salesse, H. Serne, D. Labarre, B. Basse-Cathalinat,

Address: D. Ducassou and M. Jozefowicz. Lato. Rech. Macromol., Avenue J.B. Clement 93430 VILLETANEUSE, France

In previous papers, we demonstrated that amino-acids sulfamide substituted polystyrene surfaces possessed an antithrombic activity in presence of blood plasma. These solid surfaces were heparin-like-i.e. were active as cofactors of antithrombin.

treatments on small diameter tubings made of polystyrene grafted polyethylene. The modified tubings surfaces were characterized by means of ESCA, clearly showing the presence of amino-acid sulfamides on the inside surface. These tubings were implanted as extracorporel shunts on dogs and the variations of local concentrations of labelled platelets and plasmatic proteins were recorded in situ, usin5 radioactive tracers. During the first minutes of implantation, no signlficant platelet adhesion and aggregation was observed on the walls of the tubings, whereas such events occurred on medical grade silicone tubings, despite the poor mechanical properties of the modifled tubings.

modified by such a surface treatment and characterized by ESCA, antithrombogenic devices could be developped.

Using similar experimental process, we achieved surface

By using materials with improved mechanical compliance,

A transmission rlii'l Scannin,: Clectron 'licroscopy of

in the venous system of dogs. Title luminal s u r f a c c ol an expanded PTFE prosthesis (Gore Tex)

Author(s} U.Wol f' .P.Kalmar' ,N.Dociu' ,G. Jakobs' ,H. J.SchHfer' ' ' ,

Address : t I>ept.Cardiovascular Surg..LlK F.ppendorf.Hamburp,,FRC: D.Ren2'

DepC.Surgica1 Research,Ethicon CmbH,Norderstedc I , , Depc. PathoIoey.UK Eppendorf .Hamburg

Having been in need of a suitable replacement for blood vessels in the lov pressure system, the characteristics of the PTFE prosthesis vere tested in an experiment vith dogs. A segment of 3 cn of a major abdominal vein was resected and replaced by

Core Tex prosthesis in 12 dogs in the 20 to 2 5 Kg weight range. All anastomoses were made with continuous 5-0 Prolene sutures. Heparin vas given for a period of 8 veeks after implantation. Craft patency vas monitored by phlebography. In 6 dogs, a 3 cm segment of the infrarenal vena cava was replaced by a prosthesis of the sane length and a diameter of 10 m. These animals vere sacrificed 8 veeks postoperatively. In the remaining 6 dogs. a 3 cm segment of the c o m n iliac vein was replaced by an equal length pqosthesis of an 8 m diameter. The necropsy of these animals took place after 6 months. The overall patency rate vas 8 3 . 3 % in the first group vhereas in the long term experiment it amcunted to 6 6 . 6 % . Craft occlusions vere attributed primarily to technical errors and not to intrinsic properties of the graft. Horphological characterization of the cells lining the grafts was performed using scanning and transmission electron micro - +copy. The grafts were covered in all animals with a vell developed neointima composed of similar cells as found on the adjacent host vessels. Attention vas focused on endotheliali- zation in connection with the physical properties of the expanded polycetrafluoroechylene. In a supplementary group consisting of 3 dogs, the formation and spreading of neointima was evaluated after I , 3 and 6 weeks intervals. Already during the intiaa was noticeable in close vicinity of the anstomoses. 5 veeks later the endochelialization throughout the entire length was concluded. The cells along the luminal edge of the healed graft vere packed vith pinocytotic vesicles.mitochondria, Golgy's complex and rough endoplasmic reticulum. Desmosomal bridges were also visible. The surface depicted fev microvilli- like structures. A vell defined basal lamina could also be seen. These findings strongly suggest that the cells lining the Kraft

first veek post op. distinct developing of a smooth neo-

constitute true vascular endothelium.

Title:

Authorfs): Ph.TANGUY. G.TREMBLAY. R.GUIUOTN, G.PARE,

A componatiwe h t u d y a6 t h e geometry 0 6 t he auhto- U c b i d u n c a t i u n .

. . J .BERNZER; C.GOSSELTN

Address. H 6 p a St-FnanCud d'Ahbb5e et Uruvenn~Lh L a d QUEBEC, CANADA

Auhta-6emunal b i6unca ted phohthenen ane h o l L t i n d y m- pLanted M 6ubs.titLLten ad p a t h o l o g i c a l b i W c a L L u n n . I t hat been abhehved @om p n u s t h a e n coUeoted ai alLtophy t h a t t h e heaLing p m c a h 0 6 t h e gha6.t is n u t o a t i ~ 6 a c t a h y . i n t h e 4 h d 6 mea. W e b e l i e v e thet hume h m a n h M e h&ated t o t h e mechanica l behauialvr and t h e geomethy u6 the -im@ant.

The aUn 0 6 tkin n t u d y is t o phopuhe a mud& doh a b e t t e h d u i g n e d auhto-6emuhat s y n t h e t i c p n o h t h e ~ d . I n uhden tv 4eaLize it, we have cumponed an a h. ta t in- tLcal p o i n t 0 6 wiw, measunemet& 0 6 bady-Limb n a t i o , angee and 4h&6 w i d t h ob ta ined @om .&ampla 0 6 all c o m m m u a l l y a v a i l a b l e b iduncated gna6.t l e i g k t y u n i t n l , X-Ray4 a v h t o g h a p k i a ahu- &g a namd mohphdog ic p a t t u n I h u n d h d n e g a t i v e phuta- ghapk ien ) and b i @ ~ c 1 L t i o n ~ c o U e c t e d at ~z l i tophy l e i g k t y piece,) . Mwuneme& wene peh6umed udiw m m o l o g y opt^- c a t t e c h n i q u a [ a p t i c d campahatoh, binuclLeah1.

R e ~ u e t h 0 6 d m a n a l y o i t can be hummahized at ~ u U u U b : . auhto t o i l i a c h a t c u and a h d 6 w i d t h do n u t change v m y much w a h age;

. the v a l u e 0 6 tkid hatio i n human, .ih ~ L t h i n -the hange I . 4 t o I . 8 i n agteement w a h meatuhemenCn taken u n phun- theden; . t h e a n g l e between Limb4 i n g t a 6 . t ~ in h ~ & y hupehiah to 5 degheen cn comp le te di4agneement u d h meatuned w d u a an aohtughaph.ien s i n c e .it w & e n be*ween 2 0 and 60 de- gkees; . t h e p h o s t h e t i c n h ~ 4 u 4 d t h i n w d k i n t h e hange 2 t o 5 m U e X w which i~ b i i p e h c ~ h -to obhehued w d u c ~ on cue- l e c t e d b i 6 u n c a t i u n b .

The obsehwed d466ehence i n t h e geomethy 06 b ib lvrcated g h a 6 t l compahed t o the,& phyh ioLog ica l u6enence can have impohtan2 cunhequenceb a n t h e b lood dynamico i n t h e negcun I g e n W u n u6 t u n b d e n c e o h h i g h a h e m hate1 and mudt h d p t o den ign t h e ideal p h o n t h a i A .

187

Artificial Organs Vol. 5, No. 2

Title:T%e e f f e c t of copolymerization upon t h e a c t i v i t y of

Author(s): Hi rosh i Matsumoto, Tetsuroo Takayama, Hi tosh i

Address:Department of Thoracic Surgery, Facul ty of Medicine

We assessed t h e e f f e c t of copolymerization upon t h e a c t i v i t y of t h e s p e c i f i c blood coagula t ion f a c t o r s . O u r experimental p ro tocol involved t h e exposure of c i t r a t e d standard human plasma t o 6 e thylene-v inylace ta te copolymers ( v i n y l a c e t a t e copolymerizing r a t i o ; l h mol%, 18 mol%, 25 mol%, 28 mol%, 33 m o l % and 40 m o l % ) . Polymer p e l l e t t e s t e d have been spe- c i a l l y synthes ized under c lean condi t ions and substance of known composition, f r e e of p l a s t i c i z e r and f i l l e r . Each p e l l e t was a lmost ly equal ly s i z e d . i n our eva lua t ion of t h e e f f e c t of sur faces on plasma coagu- l a t i o n f a c t o r s , we have u t i l i z e d a high r a t i o of sur face a r e a t o t h e volume of plasma exposed. Plasma has been exposed t o such s u r f a c e s f o r per iods of 30 minutes a t 25 O C with g e n t l y r o t a t i n g a g i t a t i o n . Loss of c l o t t i n g f a c t o r a c t i v i t y from plasma exposed t o t h e test sur face , as compared with a p o r t i o n of t h e same plasma incubated without such c o n t a c t , has been i n t e r p r e t e d as adsorp t ion of t h e coagulation f a c t o r s t o t h e t e s t s u r f a c e s . The p o s s i b i l i t y t h a t t h e f a c t o r XI and W were a c t i v a t e d i n t h e l i q u i d phase r a t h e r than adsorbed has been r u l e d o u t , moreover. Moderately severe l o s s of f a c t o r \mr, X,X and XU were apparent, wi th exceptions of f n c t o r XandXUexposed t o t h e LO mol% copolymerized e thylene sur face . R e s u l t s i n t h e f a c t o r V and VU were extremely high. some of high r e s u l t s suggest t h a t t h i s c l o t t i n g f a c t o r is be ing a c t i v a t e d . Fac tor I, n a n d X were l i t t l e a f f e c t e d . Fur ther f a c t o r assays performed wi thout k a o l i n demonstrated t h a t t h e f a c t o r H and XI of normal plasma following incuba- t i o n wi th t h e 40 mol% copolymerized e thylene sur face were s i g n i f i c a n t l y a c t i v a t e d . In c o n t r a s t , o t h e r member o f t h e t e s t copolymerized sur faces showed no apparent e f f e c t s on t n e f a c t o r a c t i v a t i o n . Copolymerization of v inylace t t i t e i n t o e thylene has v a r i a b l y s i g n i f i c a n t e f f e c t s on t h e u c t i v i t y of t h e s p e c i f i c blood coagulation f a c t o r s .

t h e s p e c i f i c blood coagulation f a c t o r s

Matsunaga, Tsuyoshi Yoshitake and Kenichi Asano

Univer i s ty of Tokyo, 7-3-1 Hongo, Eunkyo-Ku,Tokyo

For optimal s e n s i t i v i t y

0

P R E V E N T I O N OF PLATELET A G G R E G A T I O N I N C A R D I A C ASSIST DEVICES BY PROSTACYCLIN J.N. r a b i a n i . S. Bunting. J . O'Grady, E .Ter r ie r

Laboratoire d 'Etudes des Greffes e t Pro theses

Hdpital BrAussais, 96 r u e Oidot, P a r i s , France

Pros tacyc l in IPGIZl is known t o be a p l a t e l e t aggregation

Title:

Author(s): I . Vane, Ch. Oubost

Address: Cardiaques CNRS & Association El. Bernard,

i n h i b i t o r and a v a s o d i l a t o r . We have inves t iga ted i f PGIZ could improve haernocompatibility during cardiopulmonary bypass ICPBI i n a double bl ind cont ro l t r i a l of 47 p a t i e n t s undergoing c a r d i a c surgery.

Infusion r a t e s of 12.5 ng/kg/mn and 25 ng/kg/mn o f PGIZ o r dumny were used before and during CPB respec t ive ly . Infu- s i o n of PGIZ was stopped a t t h e end of CPB. A l l CPB t imes were g r e a t e r than 60 m n .

P l a t e l e t s counts were s i g n i f i c a n t l y higher during and a f t e r CPB i n t h e P G I Z t r e a t e d group 1116 12.5 vs 82 7 .6 p C 0.05 a t 60 mnl.

Aggregation was inh ib i ted s i g n i f i c a n t l y by PGIZ infus ion during CPB a s compared w i t h cont ro l group Ip < 0.0011. Thi r ty minutes a f t e r t h e end o f by-pass. aggregation i n the P C I Z group returned t o normal but continued t o dec l ine i n the cont ro l group l p < 0.011. Haemochron time was s i g n i f i c a n t l y increased a f t e r heparin i n j e c t i o n i n t h e PGIZ t r e a t e d group.

I n conclusion, PGIZ does s i c n i f i c a n t l y preserve p l a t e l e t s and function and p o t e n t i a t e s t h e ac t ion of heparin during CPE .

Title:USE OF HUMAN UMBILICAL CORD VEIN GRAFT (HUCVG) AS

Author(s): C h a t t e r j e e , Satya N. VASCULAR ACCESS I N NON-DIALYSIS PATIENTS

Address:4301 X S t r e e t , Sacramento, CA 95817, U.S.A.

Amphotericin B given in t ravenous ly causes s c l e r o s i s of v e i n s . Crea t ion of an a r te r iovenous f i s t u l a (AVF) t o provide a r a p i d d i l u t i o n of t h e infused agent i s an accepted technique f o r adminis te r ing t h i s drug t o t r e a t disseminated fungal in- f e c t i o n s . therapy with some success b u t use of HUCVG f o r amphotericin therapy has not been previous ly repor ted . We used HUCVG a s AVF t o compare i ts e f f i c a c y wi th t h a t of Bovine g r a f t s f o r t h i s non-dialysis use . h b i l i c a l v e i n s were removed from the cord by enzymatic d i g e s t i o n then placed i n glutaraldehyde f i r s t f o r severa ldays and then i n 50% e t h y l a lcohol s o l u t i o n . Graf t s were r insed i n heparinized s a l i n e p r i o r t o use. used 1 8 g r a f t s i n 15 p a t i e n t s . Average age was 59 (range 32- 71) years . under a x i l l a r y block on 13 occas ions and 5 opera t ions were done i n the th igh requi r ing genera l anes thes ia . were a s follows: l o c a l i n f e c t i o n r e q u i r i n g removal of t h e g r a f t i n 1 and thrombosis i n 6 (33%). who d ied from disseminated fungal i n f e c t i o n t h e incidence of successfu l completion of t h e t rea tment was 66% (11/16). This compares favorably with t h e repor ted r e s u l t s of the use of Bovine g r a f t s f o r non-dialysis use. of erythema, tenderness , aneurysm, h e a r t f a i l u r e , o r s e p s i s . The h igher inc idence of thrombosis i n t h i s group is due t o the high thrombogenicity of amphotericin B e s p e c i a l l y i n p a t i e n t s who hematocrit and p l a t e l e t dysfunction. Nevertheless we f e e l t ha t HUCVG is an e x c e l l e n t m a t e r i a l t o use f o r AVF to admin- i s t e r chemotherapeutic agents , blood products and hyper- a l imenta t ion s o l u t i o n s . The advantages of HUCVG a r e (a) i t has no branches (b) i t has an i n t i m a l l i n i n g and (c) no pre- c l o t t i n g i s necessary. d i f f i c u l t t o anastomose because of r i g i d i t y and the presence of umbi l ica l a r t e r i e s . more experience is gained.

Bovine g r a f t s have been used f o r intravenous chemo-

We

S t r a i g h t g r a f t s were placed i n the upper arm

Complications

I f we exclude 2 p t i e n t s

There was no incidence

a r e not uremic, meaning those without a low

Only disadvantage is it is more

Resul t s of i t s use w i l l improve a s

COMPARISON O F THE MECTIANICAL PROPERTIES O F SAPHENOUS

POTENTIAL VASCULAR GRAFTS . Ti t ,e :AND UN3ILIcRL VEINS AND ARTERIES PRESERVED As

P J Drury*, R van NOort-, W H Wain', J G Bennett*

. 2 Eea-nt S t r e e t . L o h n n W 1 N 2DX. Enaland Author(s): * De artment of Surgery Card io thorac ic I n s t i t u t e ,

Department of Medical Physics and C l i n i c a l

S h e f f i e l d S10 2JF. England Address: Engineering, Royal Hallamshire Hospi ta l ,

Glycerol has been used a s a preserv ing agent f o r dura mater which is then used i n card iac and neurosurgery, b u t t h e r e has been l i t t l e s c i e n t i f i c work performed o n t h e b a s i c p r o p e r t i e s o f Glycerol-preserved t i s s u e s .

The mechanical p r o p e r t i e s of human saphenous ve in preserved i n g lycero l have been compared w i t h those of o t h e r saphenous vein a l t e r n a t i v e s and wi th those of glutaraldehyde-preserved and f r e s h saphenous ve ins . The s t r e s s - s t r a i n response up to 1 N/mm2 and the s u t u r e p u l l - o u t s txength of t h e s e t i s s u e s were measured. Fresh saphemus ve in a t t a i n e d a s t r a i n o f 34.6% ? 7.1 a t a s t r e s s o f 1 N / m 2 , while glycerol-preserved saphenous ve in and glutaraldehyde-preserved saphenous v e i n reached s t r a i n s of 54.1% t 11.4 and 33.2% ? 5.8 r e s p e c t i v e l y . Comnercially-available umbilical ve in a t t a i n e d a s t r a i n r e s p n s e o f only 11.8% ? 3.5 a t a s t r e s s of 1 / N m2 and u n b i l i c a l a r t e r y a s t r a i n response o f 12.3% $ 3.9.

Glycerol-stored saphenous ve in had s u t u r e p u l l - o u t s t r e n g t h values comparable t o t h e f r e s h t i s s u e (g lycero l -s tored saphenous v e i n , 8.8 N / m ? 1.9; f r e s h saphemus vein 6.7 N/mm t 1.1). A l l o t h e r t r e a t m n t s i n v e s t i g a t e d showed c o n s i s t e n t l y lower values fg lu ta ra ldehyde-s tored saphenous ve in 4.7 N / m ? 0.9; umbilical ve in 1.9 N / m m ? 0.8; umbilical a r t e r y 1 .9 N/mm ? 0.6) . These results i n d i c a t e t h a t glycerol-preserved saphenous ve in is s i m i l a r to f r e s h saphemus ve in i n terms of mmpliance and r e s i s t a n c e to s u t u r e dehiscence. Such veins preserved according t o our technique look promismg a s an a l t e r n a t i v e to f r e s h saphenous v e i n f o r vascular g r a f t s .

188

May 1981 Communications 0

PRE\IEKTION OF CALCIFICATION I N IMPLANTEO Title: SLUTARALOEHYCE TREATED B I O L O G I C A L TISSUE.

A. C a r p e n t i e r , S. C a r p e n t i e r , A. N a s h r e f . R . Levy. Author(s): M. F i s h b e i n , N. G o u s s e f . L a b o r a t o i r e d ' E t u d e s d e s

G r e r f e s e t P r o t h e s e s C a r d i a q u e s - CNRS & A s s o c i a t i o r Address: C1. B e r n a r d . H a p i t a l B r o u s s a i s . P a r i s . C h i l d r e n ' s

Hosp. Ned. C t r . B o s t o n , C e d a r S i n a i Ned. C t r , Lo5 Angt? les , USA.

G l u t a r a l d e h ) . d e ( G l u l t r e a t e d c a r d i a c v a l v e s are a s s o c i a - t e d w i t h a h i g t , risk o f c a l c i f i c a t i o n i n c h i l d r e n . I n pre- v i o u s s t u d i e s . , w e h a v e d e v e l o p e d a n e x p e r i m e n t a l model w h i c h r e p r o d u c e d i n a n a c c e l e r a t e d manner t h e p r o c e s s of t i s s u e c a l c i f i c a t i o n c b s e r v e d i n humans and showed a good c o r r e l a - t i o n b e t w e e n :he l e v e l s o f c a l c i u m i C a + + l a n d c a r b o x y g l u t a - mic a c i d s u g g e s t i n g t h a t t h i s amino a c i d may p l a y a r o l e i n c a l c i f i c a t i o n . U s i n g t h e same e x p e r i m e n t a l m o d e l . w e h a v e i n v e s t i g a t e d :he e f f e c t o f v a r i o u s f a c t o r s on c a l c i f i c a t i o n . - Normal , low and h i g h Ca++ d i e t . - T r e a t m e n t 0' t h e t i s s u e w i t h F o r m a l i n , A c r o l e i n . D i a l d e h y d e

s t a r c h i n a s s o c i a t i o n w i t h Glu. - I n c u b a t i o n of t h e t i s s u e i n Sr++. C u + + , B a + + , Pig++ a f t e r

G l u f i x a t i o n . - I n c u b a t i o n o f t h e t i s s u e i n v a r i o u s amino a c i d s ( H i s t i d i n ,

A l a n i n , L y s i n . C h ~ l a m i n l w i t h t h e a i m o f c o v a l e n t l y b i n d i n g t h e f r ee a l d e h y d e g r o u p s l e f t a f t e r G l u f i x a t i o n .

R e s u l t s showed t h a t : - C a l c i u m die: h a d - l i t t l e i n f l u e n c e on c a l c i f i c a t i o n . - A s s o c i a t i o n Of F o r m a l i n w i t h Glu r e d u c e d c a l c i f i c a t i o n . - Sr++, Eat+ , C u t + i n c u b a t i o n had no e f f e c t . - Amino a c i d f :xa t ion r e d u c e d c a l c i f i c a t i o n .

P r a c t i c a l i r p l i c a t i o n s w i l l b e d i s c u s s e d .

A NEl! VALVULAR BIOPROSTHESIS A l a i n C a r p e n t i e r . P a t r i c k P e r i e r . E r n i e Lane , A l a i n D e l o c t ~ e . C h a r l e s D u b o s t

d i a q m s . C.N.R.S. g A s s o c i a t i o n C l a u d e B e r n a r d

Title:

A u t h o r ( s L a b o r a t o i r e d ' E t u d e s d e s Greffes e t P r o t h e s e s C a r -

A d d r e s s H a D i i Z i B r o u s s a i s , 9 6 r u e D i d o t . 75014 P a r i s F r a n c e

S i n c e o u r p r o p o s a l i n 1968 t o use G l u t a r a l d e h y d e i n t h e p r e s e r v a t i o n c8f v a l v u l a r t i s s u e . e x t e n s i v e r e s e a r c h h s s b e e n c a r r i e d o u t t c m i n i m i z e two p e r s i s t a n t d r a w b a c k s : t r a n s v a l - v u l a r g r a d i e n t s and f a t i g u e l e s i o n s .

S i n c e t r a n ~ v a l v u l a r g r a d i e n t s r e s u l t f rom t h e i m p e d a n c e c a u s e d by a s t e n t a n d t h e a o r t i c r e m n a n t S u p p o r t i n g t h e c u s p s a new s t e n t h a s b e e n d e s i g n e d so a s t o i m p l a n t t h e v a l v e i n t h e s u p r a - a n n ~ l a r p o s i t i o n . O n l y t h e c u s p s of t h e s u p r a - a n n u l a r v a l v e [SAV) r e m a i n e x p o s e d t o t h e b l o o d co lumn. I n v i t r o tes ts h s v e shown t h e t r a n s v a l v u l a r g r a d i e n t s t o b e m i n i m a l , a v e r e g i n g 8.5 mmHg a t 15.1 l /mn f o r t h e 21 mn s ize . TheSAV h a s a s h o c k a b s o r b i n g s t e n t so as t o r e d u c e t h e s t ress o n t h e c u s p s .

F a t i g u e t o s t i n g o f c o m m e r c i a l l y a v a i l a b l e t i s s u e v a l v e s u s i n g p u l s e d L p l i c a t o r s h a s d e m o n s t r a t e d a n a v e r a g e d d u r a b i - l i t y o f 450 m i l l i o n c y c l e s w i t h a w i d e r a n g e f r o m 10 t o more t h a n 6 0 0 m i l l i o n c y c l e s ,

Of p r e p a r a t i o n of t h e c o m n e r c i a l l y a v a i l a b l e v a l v e s r e v e a l e d t h a t t h e l a r g e v a r i a t i o n s i n d u r a b i l i t y c o r r e l a t e d w i t h v a r i a t i o n s i n h i s t o l o g i c a l s t r u c t u r e s a n d r e s u l t e d f r o m i n a - d e q u a t e p r e s e r v a t i o n d u r i n g t h e s h i p p i n g p r o c e s s . A t e c h n i q u e u s i n g a b a l a n c e j s a l t s o l u t i ~ n was t h e r e f o r e d e v e l o p e d t o i m p r o v e s h i p p i n g c o n d i t i o n s . E l e c t r o n m i c r o s c o p l c s t u d i e s h a v e Shown t h c t h i s t o l o g i c a l l e s i o n s h a v e b e e n e l i m i n a t e d and f a t i g u e t e s t : t u d i e s have shown a n i m p r o v e d a v e r a g e d u r a b i l i - t y up to 650 n t i l l i o n c y c l e s w i t h l i m i t e d v a r i a t i o n s .

34 SAV h a w b e e n i m p l a n t e d c l i n i c a l l y i n t h e p a s t 6 m o n t h s w i t h no m o r t a l i t y a n d no c o m p l i c a t i o n .

E x t e n s i v e r e v i e w o f t h e h i s t o l o g y a n d t h e e n t i r e p r o c e s s

0

Title: THE SURFACE BARRIER OF FRESH AND GLUTARALDE-

Author(s): Bo Dinesen, Lone Sans t rup and I .H.Ryqg HYDE TANNED PORCINE PERICARDIUM.

Dept. R , R i g s h o s p i t a l e t , U n i v e r s i t y Hospj t a l of Copenhagen.

Scanning e l e c t r o n microscopy o f t h e s u r f a c e of b i o p r o s t h e t i c c a r d i a c v a l v e s has shown loss of t h e e n d o t h e l i a l cover ing w i t h p o s s i b i l i t i e s f o r e n t r a n - c e of plasma p r o t e i n s i n t o t h e i n t e r s t i t i a l spaces o f t h e v a l v u l a r connec t ive t i s s u e .

b i o p r o s t h e t i c v a l v e s has been examined by d i a l y s e s i n o r d e r t o t e s t t h e p r o t e i n b a r r i e r of t h e mesothe l i a l c e l l c o v e r i n g and t o t e s t t h e e f f e c t o f pro te - i n c o a t i n g of t h e s u r f a c e by means of g l u t a r a l d e h y - de tanning t e c h n i c .

pha te b u f f e r e d s a l i n e wi th t h e per icardium a s a d i a l y s i s membrane, t h e m e s o t h e l i a l s i d e f a c i n g towards t h e sgrum. D i a l y s i s was performed over t h r e e days a t 3 7 C under r o t a t i o n of t h e chamber. Dai ly samp- l e 5 were ana lysed f o r t h e t o t a l passage of serum p r o t e i n s over t h e membrane and c h a r a c t e r i z a t i o n of p r o t e i n s i n t h e b u f f e r was e s t i m a t e d by agarous g e l e l e c t r o p h o r e s i s . Scanning e l e c t r o n microscopy w a s performed b e f o r e and a f t e r t e s t i n g .

Fresh per icard ium s t o r e d i n Ringer l a c t a t e so- l u t i o n up t o 5 H o u r s b e f o r e t e s t i n g showed passage of 3 7 % of t h e serum p r o t e i n s over 3 days. P e r i c a r - dium t r e a t e d w i t h g l u t a r a l d e h y d e immediately a t t h e s l a u g h t e r i n g passed only 1 . 5 % . Pericardium p r e s e r - ved wi th deep f r e e z i n g b e f o r e g lu ta ra ldehyde t a n - n ing showed passage of 25 - 30 %. P r o t e i n c o a t i n g wi th g l u t a r a l d e h y d e of s i m i l a r l y preserved and t r e a t e d per icard ium was d i s a p p o i n t i n g , a s from 8 . 5 t o 3 1 % of t h e serum p r o t e i n s passed t h e membrane. NO s p e c i a l s e l e c t i o n was found by l e a k i n g membranes

P r o t e i n c o a t i n g by g lu ta ra ldehyde t a n n i n g tech n i c i s thought t o be i n s u f f i c i e n t f o r o b t a i n i n g a s u f f i c i e n t s u r f a c e b a r r i e r .

Porc ine per icard ium used f o r manufacture of

Fresh human serum was d i a l y s e d a g a i n s t phos-

0 AORTIC VALVE REPLACEMENT I N PATIENTS W I T H

~ i t l ~ : NARROW AORTIC ROOTS BY MEANS O F A NON STEN TED, XENOGENIC BIOPROSTHESIS.

vo ld , A . and Rygg , I . H . Author(s):Berning, J., Buch, J . , Vilhelmsen,R. , Wenne-

Address: Department R , R i q s h o s p i t a l e t , U n i v e r s i t y H o s p i t a l of Copenhagen.

Ear ly exper imenta l and c l i n i c a l r e s u l t s wi th a new non s t e n t e d des ign o f c a r d i a c va lve b iopro- s t h e s i s w i t h l e a f l e t s made from a fo lded (double l a y e r ) p i e c e of t h i n per icard ium w i t h t h e smooth m e s o t h e l i a l s i d e f a c i n g outwards was p r e s e n t e d a t t h e ESAO meet ing i n 1 9 7 9 (0rnvold e t a l . ) .

This r e p o r t concerns a o r t i c v a l v e replacement w i t h t h i s k ind o f b i o p r o s t h e s i s i n 6 p a t i e n t s wi th narrow a o r t i c roots. The t h r e e l e a f l e t b iopros the- s is was i n s e r t e d i n a " f r e e hand" manner u s i n g 3 cont inuous s u t u r e s , one f o r each l e a f l e t p o r t i o n .

P r e o p e r a t i v e l y a l l p a t i e n t s had AS w i t h g r a - d i e n t s ranging from 28 t o 9 5 mm Hg. Three p a t i e n t s a l s o had A 1 g r a d e I - I V , and one p a t i e n t had m i t r a l s t e n o s i s r e q u i r i n g replacement .

p .0 . w i t h c a r d i a c c a t h e t e r i z a t i o n , angiocard iography, echocard iography, e x t e r n a l c a r o t i d p u l s t r a - c i n g , phonocardiography and c l i n i c a l s t a t u s . A sa- t i s f a c t o r y f a l l i n p r e s s u r e g r a d i e n t s from mean 55 go 1 4 ( 0 - 2 0 ) mm Hg was found. NO changes were obse rved of cusp t h i c k n e s s , s e p a r a t i o n o r eccho i n - t e n s i t y .

and s tayed w i t h i n normal l i m i t s . Both opening and c l o s i n g c u s p v e l o s i t y were decreased compaired t o normal, b u t remained c o n s t a n t over t h e obs .per iod .

m i t r a l v a l v e . However, one p a t i e n t had a f i n e ear . ly d i a s t o l i c f l u t t e r of t h e a o r t i c cusps a s a s igr of A I . E a r l y d i a s t o l i c murmur was p r e s e n t i n 4 p a t i e n t s , who a t aor tography a l l had v i s i b l e A I . T h i s may be r e l a t e d t o t h e decreased c u s p v e l o s i t : of t h e s p e c t a l des igned l e a f l e t s .

Reexamination was performed 6 t o 2 0 months

L e f t v e n t r i c u l a r e j e c t i o n t i m e decreased p .0 .

N o p a t i e n t s showed d i a s t o l i c f l u t t e r o f t h e

189

Artificial Organs Val. 5, No, 2

0 . A NEW PULSATILE ROLLER PUMP FOR USE IN HEART-

Title: LUNG MACHINES AND AS CARDIAC ASSIST DEVICE

Author(s): Patil, K.M., Reul, H.

Address: Helmholtz-Institute for Biomedical Engineering Goethestr. 2 7 / 2 9 , D-5100 Aachen, West Germany

A number of extracorporeal pulsatile pumps for clinical application have recently become available. It is found that especially the centrifugal pumps are capable of producing only low aortic pressures and volume flow pulses. Therefore, it is desired to design a pulsatile pump which produces pressures and flow pulses closer to the physiological situation. A high value of pulsatile flow amplitude not necessari- ly produces a proper volume output. Therefore, pulsatility is redefined such as to maximize the product of volume amplitude and volume output.

The pump we have developed and built has two rollers which hold the tube in crossed position and the pumping action takes place due to squeezing of blood between the roller (holding the tube in tension) and a free boundary. The desired flow rate is obtained by properly choosing the roller diameter, roller center distance, tube strain, and the angle between the roller arms. Series of tests were conducted on the pump, using silicone tubes of 12 and 16 m I.D. It is found that the pump (with 16 mm I.D. tubing) and optimized conditions produces flow amplitudes of 70 to 210 ml/s and flow rates from 3.1 to 7 . 3 3 litlmin f o r pump speeds varying from 50 to 150 rpm. An earlier version of this pump with (higher backflow) the tube going around the rollers instead of being in crossed position was tested for hemolysis and was found to give about one third hemolysis reported for pulsatile roller pumps by other investigators. At the time of writing this paper, the present version of the pulsatile pump has yet to be tested for hemolysis.

It is hoped that this pulsatile roller pump, because of its good and near physiological nature of pulsatility and its

assist. Of use and control, could possibly be used for cardiac

C O l . D X M D TiUGGlXU2lJ PR2C(JlK!I?LtY UXJG IIIl’USICB~

TI011 u.T ISCIEI LIC ,UJl) NONIXlUiiIC i~iYUCh;’B~l[Uii Title: dm u r r i & ~ o I r r I C DALLooN 1TJIIPIIJG Pol? 1’1KlTEC - Author(s): IC.-P. Liiidcnau, 11. Goos, E.4 . Ikause ,

H. D a v i d , L. IircOler aiid J. Liebe t ru th ~ d d r ~ s s : Su rg ica l C l i n i c of Char i t6 , IIuInboldt-

Univ.; Acad. o f Science, Der l in , GU!I

ln 116 xongrel docs i t was t r i e d t o t‘ind out how f a r i n t r a a o r t i c balloon puxipinc; (LWP) appl ied s o l e l y and in coinbination w i t h g lucose- insu l in- po tass iu~i i (GII;) and p ros t acyc l in i i u ~ l i t i n f luence thc degroe o€ a c u t e inyocardial isc1iei:iia. The ischexdn l a s t c d 3 hours. ‘llio d i r e c t c d drug app l i - c a t i o n i n t o the a o r t i c r o o t was c a r r i e d out by o l e c t r o n i c t r i g e e r i n g du r ing the d i a s t o l i c aug- trientatioii via a procoronary c a t h e t e r . The i s o l a - t c d use of W P sw-gcsted n o pro tec t ion of the energy-rich phosphates. Thc bes t p r o t o c t i v c o f f ec t was achieved IJY coi.ibinecl t r i c c e r e d pre- coronary G I K i i i€usion i n coinbination w i t h IABl’. T h e ATP va lue (n nio l / iu l : w.w.) , i n tlic isc1iei:dc a rea w a s 3 , 0 6 and i n the non-~schernic 4 , 96 i n cociparisoii t o 1,96 and 3 , 9 9 r e s p e c t i v e l y i n the c o n t r o l G r o u p . The c r e a t i n e pliosplmtc w a s 4.12 in tlie isclieiiiic and 9 , 3 3 i n t he nonischernic a rea i n c o n t r a s t t o 2,3G and G , g 9 i n the c o n t r o l crow. U u r technique o f f e r s t h e fo l lowhe ; advantages :

1 . a d d i t i v e s~u!ii.wtioii of iAIlI’ and substrate

2. high drug concent ra t ion i n the myocardium

3 . smaller s i d e off‘ects and

4 . c l i n i c a l use of instable substances.

SUPPlY

0 . PATHOPHYSIOLOGICAL ANALYSIS OF THY 3 EXPE-

Title:RIbDNTS WITH THE TOTAL ARTIFICIAL HEART (TAX) WITH MORE THM 100 DAYS OF SURVIVAL

Autho&): J a r o m i r Vagkb, E.Urbinek, Jan Valikb,

~ d d ~ ~ ~ ~ : V.Pavli8ek , 0.30 t313V6, T. Slgdek J.Eerni P.Cuba, M.Doati1, S.Doleie1,

1nat.of PathDphyEiol. , Fac.of hled. ,UJEP ERN0,ESSR Fourth g rouLof our experimentson TAH i s rapre- sented by t ee calvea. Calf No 50 “Hasan3‘1, survived 150 days, c a l f No 51 89Dalibor1u, survived 142 days, c a l f No 52 ”Samson“, survived 104 days. Mean s u r v i v a l was 132 days. Cauae of dea th i n t h e c a l f No 50 waa i n t r a c t a b l e b leeding , c a l f No 51 terminated acc iden ta l ly i n f u l l h e a l t h , and i n the c e l f No 52 diaphragm leakage i n t he r ia t a ide was t h e main cauae of death. The c o n t r o l and d r iv ing regime s l i g h t l y d i f f e red i n experiments N3 50 and No 51 f r o n t h e experiment NO 52. Auto- r egu la t ion o f suc t ion wi th t h e v a r i a b l e s y s t o l i c time was used in a l l t h r e e ca lves on t h e l e f t aide. The CVP s l i g h t l y increased i n a l l t h r e e ca lves i n t h e course of t h e experiments. The anti- Coagulation regime was e a a e n t i a l l y t h e same i n the ca lves No 51 and NO 52, i n t h e c e l f NO 50 t h e prothrombin time was maintained a t l i t t l e h ighe r l eve l s . The autopsy sf t h e c e l f No 50 showed ty- p i ce l s i g n s of b leeding , preponderantly loca l i aed i n t h e G I t r a c t . I n the a c c i d e n t a l l y terminated experiment ND 51 t h e c a l f was without any patho- lDgice l c l i n i c a l changes i n the time o f dea th and n e i t h e r macro- nor microscopica l aarked patholo- g i c a l changes were found. P a t h o h g i c a l changes f o m d by t h e autopsy sf t h e c a l f No 52 Con3iSted mainly o f t h e en larged l i v e r . Pannus waa found i n the c a l f No 51 and No 52, no t i n t h e c a l f NO 50. I n t h e c a l v e s N o 5 1 and No 52 marked r egene ra t ion o f t h e ad rene rg ic nerve t e rmina l s was s t a r t e d . S i l v e r impregnation technique (Bodian) has shown ingrowth of t h e nerves i n t o t h e pannue tiasua.The r egene ra t ion of t h e neu ra l adrenerg ic metabolism i n t h e a t r i a l t i s a u a which i a cDmpletely d i s t u r - bed i m i e d i a t e l y s f te r the TAH implanta t ion c sa be the b a s i s f3r the normal a t r i a l func t ion .

0 .

Tit le : Microcmputer-controlled electromagnetic

Author(s): N. NeSSler, R. Schis tek , W. Seidenbusch,

Address: University of Innsbruck

d r iv ing un i t f o r a r t i f i c i a l hea r t s

E. Gornik, Z . Unger

A-6020 Innsbruck/Austria

For t h e c l i n i c a l appl ica t ion of l e f t ven t r i cu la r a s s i s t e d devices (LVAD) it is requi red t o d r i v e t h e a r t i f i c i a l hea r t w i t h a s a fe ty chamber i n order toBavoid massive embolies i n t h e case of membrane rupture . T h i s requirement can be f u l - f i l l e d by means of an electromagnetic dr iv ing system which cons i s t s of a double solenoid and a l inkage which d r ives a s a fe ty cnanber. This s a fe ty chamber a c t s a s a conver te r of t h e l i n e a r mechan- i c a l novement of t h e armature i n t o a hydraul ic ? ressure wnich ac tua te s t h e menbrane of t h e a r t i f i c i a l h e a r t .

To con t ro l t h e system a pos i t i on sensor poten t io- meter ( r e l a t e d t o t h e volume of moved l i q u i d ) i s used with a s ing le card microcomputer. Tne kontrol program i s permanently s tored i n t h e microcom- pu te r , t h e con t ro l parameters ( s y s t o l i c and d i a s t o l i c a re s su re , a i sp laced volume, frequency) a r e d isp layed on a CRT-monitor and can be changed v i a keyboard.

The d r iv ing u n i t i s powered by mains and/or accumulators givinq a hiqh amount of secu r i ty and a rood dea l of movabili ty f o r long-time experiments.

With such a nicrocomputer-controlled system it i s poss ib l e t o d r i v e an a r t i f i c i a l h e a r t i n a s e l f - r egu la t ing automatic mode or i n a s e l e c t a b l e fixed-frequency mode.

190


N E W D E T A I L E D PARAMETERS FOR T A H IN H U M A N

V NTRICULOKRAPHY. Tit'e: APPLICATION D E T E R M I N E D BY MEANS OF

Author($: H. W. P s n n e k , E. 5. B iich erl

Address:

BIPLANE

H 1 i n i k um Char 1 o t t e nburg /Exper i m e n t e l 1 e Chirurgie, 1 Berlin 19

To achieve an optimal form of a blood-pump adaptive to human anatomy mostly casting - forms of human cadavers are used, yet with the following disadvantages: a) the dynamism of the heart and the adjacent organs is not considered within this steady-state: b) due to the unphysiological filling-pressure an objectivation of the diastole is not practicable: c) a comparisonwithnormal or morphologically altered hearts turns out to be as difficult as the production of casting-forms in such a big number. The technique in question, however, does not show the shortcoming8 mentioned above. Biplane ventriculograms in 30 -FWO and 60°-LA0 -projection with 100picture/sec. (with high speed-camera) were ascertained with 30 patients in lying posture. The ventricular parameter (see below) were delineated in end-diastolic position. The third construction of ventricular inflow and outflow was found out by graphic representation from RAO- and LAO-projection. By using biplane cine frames the original values could be recorded exactly. The applied method gives a precise measurement of axial angle, outflow-stream and ventricular length. A comparison between animal-pumps and the discovered ventricle-forms proves that blood- pumps for human application require an essential improvement.

Title: DESIGN A N D REALIZATION OF TAH-PUMPS F O R

Author(*): H. J .Pannek , E.S.Bbcher1

H U M A Iil 4P P L I C A T I 0 N

Address: K 1 i ni kum C h a r l o t t e n h u r g/ Exper i m e n t e 1 l e Chirurgie, 1 B e r l i n 1 9 ,

Different types of new-found artificial blood- pumps for human adaptation were applicated in 12 cadavers. In the 1. step the ventricles were built of deformable plasticine in order to compare the different anatomical situations and to carry out a rough outline of the blood-pumps. In the 2 . step these basic-concepts deriving from the first four adaptations were provided as silastic-dummies without diaphragms. The followins demands were considered to be important: - the pumps should fit well into the thorax and the pericardium sac:

obstruction at the atria and the big vessels:

lation rate.

- the pumps should be easily connectedwithout

- the pumps should deliver a sufficient circu- After the implantation the different models were examined with the help of x-ray for a good fitting. The results of these studies show that the so- called "pick--a-back" pump with circle ventricles (stroke volume left: 140ml/right: 115ml) proved to be the best of 20 different types.

PHYSIOLOGICAL ANALYSIS O F GOATS IMPLANTED H Y B R I D Ti t l e T Y P E TDTAL ARTIFICIAL HEARTS ( H T A H ) K.Atsumi, I.Fujimasa, K . Imachi, H.Miyake,

Author(s N.Takido, M.Nakajima, A.Kouno and T.Ono I n s t i t u t e of Medical Elec t ronics , Faculty of Med.

Address University o f Tokyo, Hongo, Bunkyo-ku, Tokyo, JAPAN

In the hybrid type to t a l a r t i f i c i a l hear t (HTAHJ expen- ment, the natural hear t was remaining to beat but the as- cending aor ta and the pulmonary arter.y were occluded com- p le te ly . tained by the a r t i f i c i a l heart t o t a l l y and the coronary Circulation was maintained by flow from the l iv ing heart . Object of the work i s t o analyse the physiological features of HTAH implanted goats.

In our long survival cases of HTAH experiment, th ree goats survived more than 7 months l a t e ly , a n d the longest survivor l ived 288 days. I n post operative cource, the goats have l ived well , and the value of hematocrit and to ta l protein has been maintained normal, and anemia and a sc i t e s which usually accompanied i n t h e long surv iva ls have not experienced,

un t i l death o r the time of forcedly f i b r i l l a t i n g . No spec i f - i c change was observed on E C G follow u p . i c a l measurement of natural hea r t , the hear t showed n o signs of functional disturbances fo r more t h a n three months and responded well t o treadmill exercise. Left vent r icu lar pressure and TTI were elevated postoperatively and dp/dt did n o t decrease.

From c i rcu la tory physiological measurement, the response t o the load of exercise was s imi la r to the response of non- hybrid type hear t inplanted goats. the body f l u i d balance seems qu i t e d i f f e ren t from the other type of TAH experiments.

The difference between hybrid type and f i b r i l l a t e d type experiment, which includes excised natural vent r ic le type experiment, i s originated from the a c t i v i t y of cardiac receptors. I n the fonner,the natural hear t was kept beating t o perfuse coronary a r t e r i e s and the hear t muscle and the receptors seems to be in t ac t . On the contrary, the l a t t e r type has sicked receptors and the c i r cu la to ty homeostasis would be disturbed markedly f o r one month a f t e r a r t i f i c i a l hear t implantation.

The pulmonary and systemic c i r cu la t ion was main-

The beating o f the remained natural hear t was continued

From hemodynam-

B u t chronic change in

EVALUATION OF CARDIAC VALVE PROSTHESIS FOR APPLICATION O F ARTIFICIAL HEART PUMP

I.Fujimasa, K.Imachi. N.Takido, K.Atsumi Address: I n s t i t u t e of Medical Elec t ronics , Faculty of Med.

University o f Tokyo, Hongo, Bunkyo-ku, Tokyo,JAPAN

d i f f e ren t decision standards from cardiac-valve pros thes is . Today, new generation of ra t iona l ized cardiac-valve prosteses were introduced t o a r t i f i c i a l hear t pump, b u t many of the valves were doubted t h e i r du rab i l i t y , inadequate hydro-dynamical response and expensiveness. The t a rge t of the work i s t o develop new adequate t e s t ing method f o r a r t i f i c i a l hear t pump valves and evaluate a few commercial ava i lab le cardiac-valve prosthesis. (METHOD & MATERIALS) Tested valves were in s t a l l ed in the a r t i f i c i a l hear t pump in s i t u and mounted to a mock c i rcu- l a t ion . Bjork-Shiley, Lillehei-Caster, OmniScience,St-Jude, Hall-Caster, Star-Edwards ba l l and Star-Edwards disk o f 18 mn measured diameter of o r i f i c e were t e s t ed . pressure-gradient vs flow, valve-Lissajous ' figures were recorded a t various driving parameters. (ANALYSIS) One pumping cycle was divided four phases. (Phase 1 ) valve opening unstable phase;(Phase 2) valve opened quasi- steady phase; (Phase 3 ) valve closing unstable phase; (Phase 4) valve closed quas is tab le phase. Valve Lissajous' f igures were analysed during each phases separa te ly . For the a r t i f i c i a l heart valve, the hydrodynamic cha rac t e r i s t i c s during phase 1 and 3 played important a c t f o r the function of the pump and du rab i l i t y of the valve. On the contrary, in the a r t i f i c i a l heart pump, the power lo s s due to pressure gradient across the valve can be cancelled by driving force. Unsteady pressure waves gives strong impacts on the valve occluder and sometimes the occluder i s broken. Pressure shock wave in the pump a l s o influenced upon durabi l i ty of the pump. Pressure s e n s i t i v i t y of a r t i f i c i a l hear t was influenced upon valve cha rac t e r i s t i c s . B u t flow speed across the the valve was a l so a f f ec t s thrombus formation a t the valve ring. T h e optimal valve s i z e and adequate design of the valve was decided r a t iona l ly . Required performance charac- t e r i s t i c s of a r t i f i c i a l hear t pump valve were exhibited in the report .

Author(s) :

The a r t i f i c i a l hear t pump valves should be chosen

On a p la in of

191


MICROPROCESSOR-BASED CARDIAC OUTPUT Title: MEASUREMENT IN CALVES WITH

PNEUMATIC ARTIFICIAL HEART Author(s): A. Spiegelberg, S. D. Nielsen, K. Affeld,

Addre=: Klinikum Charlottenburg, Exp. Chirurgie, J. Frank, and D. B. Olsen

Spandauer Damm 130, D-1000 Berlin 1 9

In the total artificial heart (TAH) research, survival times of more than 200 days have been obtained. The pnewnatic artificial heart consists of two orthotopic implanted blood pumps connected to an extracorporeal actuator. Physiological studies on long-term, TAH experiments require continuous reliable measurement of cardiac output (CO). The CO is the most important parameter in assessing long-term pump performance. None of the current CO measuring and monitoring devices pennit noninvasive, versatile, inexpensive on-line methods.

A microprocessor-based system was developed which allows continuous calculation of CO fran air pressure and air flow signals. The system consists of a single board microcomputer, an A/D, D/A con- verter board and a thermistor anemometer circuit board. The air driving pressure of the right heart is used for the calculation of CO. The right heart air flow signal is acquired using a constant temperature anemometer. All the linearization and processing are done digitally by the microprocessor. The calculation of CO fran the acquired data is done using an equation which was derived from a previously published method.

Mock circulation tests show good correlation of the newly designed system's output compared with the results of turbine flow measurements (R=O.88). Animal tests show good results.

Title: A FREE-FLOATING BODY AS THE ROTOR OF A CENTRIFUGAL BLOOD PUMP FOR LHAD OR TAH

Author(s): G.Bram, P.Novak, D.B.Olsen'

Address: IFT,Dept.Medical Electronics,Munich,West Germany *Univ. of Utah,Div.Artif.Organs,SLC,Utah,USI.

The implantable blood pumps used nowadays are all positive-displacement pumps. This operating princinple involves valves as well as a flexible membrane for volume displacement Assuming a physiological pump rate, approximately 3.10' strokes per year result, thus critically limiting the lifetime of the pump. Experiments to overcome these problems by the use of centrifugal pumps with a low hemolysis rate have shown a pronounced formation of blood clots in the vicinity of the rotor-shaft bearings and seals, thus limiting the allowable period of use.

The above-mentioned problems can be solved by the use of a pump rotor, which floats without contact in the pump housing. To achive this, the rotor is kept in place and rotated by an electromagnetic field. The system does not involve bearings, seals or any flexing parts. A laboratory prototype of such a pumping device provides a pulsatile or non-pulsatile flow.

Haemodynamic response in long term surviving calves with Impeller b ivent r icu lar a s s i s t devices: StoD, F. , B.M. Kemkes , J. Hager, R.Schistek,

Author(s) :

Address: F'Unger I . Surgical C1 i nic,Uni v . of Innsbruck ,Austria Department of Cardiac Surgery, Univ. of Munich, Ge ma ny

Non pu l sa t i l e b ivent r icu lar a s s i s t devices (Imp-BVAD) by means o f impeller blood pumps i t i s possible to maintain the whole c i rcu la t ion while the vent r ic les a re to t a l ly u n - loaded. This could be c lear ly demonstrated in acute experiments and documented especially during cardiac f i b r i l l a t i o n o r a r r e s t . I n f i ve long term surviving calves without cardiac f a i l u r e u p t o 15 days the haemdynamic response changes a f t e r 24 - 36 hours; the natural beating heart s t a r t s to e j e c t again, but toward an increased a f te r load the a r t e r i a l pressure r i s e s in mean up to 150 nun Hg. Soon as the l e f t impeller pump (Imp-LVAD) i s turned o f f , the a r t e r i a l pressure drops i n mean 20 %. Is the r i g h t impeller pump (Imp-RVAD) addi t iona l ly turned o f f , the a r t e r i a l pressure decreases again with 10 % in mean, the a r t e r i a l pressure-amplitude enlarges; the a t r i a l pressures a re remaining constant. Are t h e pumps turned on, reproducible t h e increasing e f f ec t o f the a r t e r i a l pressure can be observed as well as decreasing of the frequency and reducing the a r t e r i a l pressure-ampli tude. The cause of termination i s thromboembolism despi te of exact heparinisation. The traumatic haemolysis varies daily between 3.1 mg % and 25.3 mg %, in mean the values a re 12 mg I.

' with support of the Austrian Research Council, p ro jec t number 3829.

0

Tit,e: EXPERIENCES WITH A NONPULSATILE TORROIDAL- PUMP FOR THE FUNCTIONAL LEFT HEART REPLACE-

MENT Author(s): U.Losert,K.Bauer,E.Horcher,F.Eckersberger

Address: II.Surgica1 Clinic, univ-Vienna, ~ustria

As alternative to the pulsatile pneumatically driven membrane pumps,a nonpulsatile,electromagne- tically driven torroidal-pump (Biomedicus Inc.) for the functional left heart replacement was investigated.In 8 acute experiments in calves the centrifugal pump,tested over 24 hours,showed its hemodynamic efficiency to take over the total cardiac output to release the left ventricle in pressure and volume completely. In one case circulation was maintained over 7 , 5 hours despite of fibrillating heart with right atrial pulsation.The nonpulsatile central aortic pressure lies 1 7 % over the systolic pressure.The right ventricular after- load is decreased 14%,cardiac output is increased 36% appr.The flow in the A.circumflexa was decreased 2 3 . 5 % though myocardial 02-consumption was decreased significantly.In another series of 5 longterm experiments (up to 64 days) the mechanical blood traumatisation caused by the pump (pump flow 4-8 l/min) was investigated.Only insignifi- cant damaging influence of the pump was seen.Hemo- lysis was within physiologic values up to lo mg%. Sporadic peaks in hemolysis after 3-5 days pumping were caused by the pump design and decreased immediately to normal values after changing of the pump device.The awake in their vital functions hardly affected animals showed normal physiologic reactions during the whole experiments.In 2 long- term calves the pump was explanted and both animals showed further normal physiologicbehaviour Therefore this nonpulsatile pump-system lends it- self to the left heart support because of its hemodynamic efficiency as well as the small mechanic blood-traumatisation.

F.Stellwag,H.Stiihr,H.Thoma,E.Wolner

Supported by the Ludwig Boltzmann-Foundation and the w w ian Reasearch Council

192

May 1981 0

Communications 0 .

A SEAL-LESS CENTRIFUGAL PUMP DESIGN FOR THE ELIMIN- ATION OF HEAT INDUCED THROMBUS FORMATION

Author(s): Belenger J., Jeanjacquot A . , Knight C.J.

Address: Expsrimentale, l0,route des Jeunes, 1227 Geneva, Fondation Coeur Artificiel/Lab. de Chirurgie . Switzerland.

As previously described by our group, centrifugal pumps can generate low rates of haemolysis at constant r.p.m. tieing also easy to handle, and not employing flexing surfaces subject to degradation, the device would Seem highly Suit- able for short or medium term external circulatory support.

The two currently available pumps are rather disappointing from this point of view for both suffer from thrornbogenesis underneath the impeller, compromising even short term use (5-10 hrs) and even being the source of pump occlusion by thrombo-embolism in long term support. Both devices employ flexible shaft seals in their design and though subtly employed, these seals are subject to heating and degradation. In the case of the Biomedicus device, material from the seal is deposited upon t h e shaft and the local temperature is in excess of 42OC when pumping saline.

A new bearing design developed in our Laboratories was used to overcome this problem, significantly reducing the heating effect and in no way compromising pump performance or formed element trauma. The torque requirement for driving the rotor was also reduced - an important consideration for the magne- tically coupled drive systems of these devices.

Tit,e: Pathological-anatomical findings in calves after total artificial heart replacement.

Author(s): H . We i deman? , Ch . G roi3p-5 i e5 t r u p , K . Ger 1 ac h , A.Kaufmann , E.5.BUcherl

Address: C h i r u r g . K l i n i k , K j n i kum Char lot tenbu rg , Freie Univ.Berlin, Inst. f.Veterinarpathologie,

Berlin

The gross and microscopic histopathological findings in 20 calves living between 29 and 194 days after total artificial heart replacement are repor- tet. The most serious problems are caused by mechanical failure of the system,membrane leakage (ii),driving tube disconnectionill. Further another complication gets growing importance: inflow and outflow obstruction by thrombus and pannus formation a t the four-phase-junction-area between artificial heart and the natural tissue ( 7 times cause of death). Thrombembolic infarctions were seen mostly in the kidneys but also in the spleen and Lungs. Only in 3 calves was found an infection along the driving tube, in 1 case a mediasfinitis, 1 animal died developing a septic shock. The right atrium was always enlarged but Less in the latest animals where the cardiac output was higher. Hepatomegaly was found in 13 calves, often combined with ascites, especially in cases w i t h low cardiac output. Histo-pathological: Fibrosis and centrolobular l i - ver cell necroses. Some animals had chronic lung congestion and terminal edema. 'In 12 calves gastric erosions without bleeding.

Beside the mechanical faiture from biological point of view the interface between living and artificial material seems to be important and inflow and outflow stenosis by pannus formation i s an unsolved problem.

Future research work must be also concentrated on the development of adequate hemodynamic regulation.

Title: Late survival in patients requiring the intra aortic ballon pump following open heart surgery.

Author(s):C.Minale M.O.,N.P.Bourg M.D. .P.Bardos M.D. and

Address: Dept. thoracic and cardio-vasc. surgery.University B.J.Messmer M.O.

Aachen. Goethestrasse 27-29, 5100 Aachen, Germany

Since 1977, 1900 patients underwent open heart surgery for acquired heart disease in our institution. Forty-three patients ( 2 , 3 % ) required the intra-aortic ballon pump (IABP) because of extreme left ventricular failure and/or intractable ventricular arrhythmia following cardiopulmonary by-pass. Of these patients, 8 (18.6%) died intra- operatively and 5 (14,3%) post-operatively, the cumulative hospital mortality being 30,2%. No complication related to the use of the IAEP was observed. Twenty-eight patients were followed up to 32 months after operation with a total follow-up of 27,3 patient years. Mean follow-up was 12.1 months t 1,E SEM. Two patients were lost to follow-up. The 1 year actuarial survival was 65% (95% confidential limits : 26%-85%), including hospital mortality. Sixty % of patients are NYHA class I, 25% class I 1 and 15% class 111. We conclude that IABP counterpulsation allows to save the majority o f patients which cannot be weaned off cardiopulmonary by-pass because of severe left heart failure and/or ventricular arrhythmia. Furthermore 85% of these patients are NYHA class I or I1 in the late post-operative period. Nevertheless the annual attrition in these patients is significantly higher than in patients who did not require the IABP (7.3% versus 1% p=D,OO2).

Synergic effect of 250H03 and 1,25(OH)2D3 in renal oste

.hen G. ,Taccone Gallucci M. ,Eonucci €:.Ballanti P:,

Cinotti G.Atand Casclani C.U:.

Title: odystrophyois unrelated to 24,?5(OH)2D3 levels.

AuthorW: Matteucci M.C?,Bianchi A.R:,Eranchini G: ,Picca S:,

Address: biv.di Neffologia',5°Patologia ;hi2 ,Ist.di Anatomie

13 patients on maimtcnance hemodialysis with ROD were treated with 250HD3 and 1,25(OH)zD3.4 received 250hlJ3, I-l.+g/kg/day (group A),6 lS25(OH)2D3, 0.5-lpg/day(grou? B)and 5 1,25(0H)2 D3+250HD3, 0.5-+g/day and 0.5-Q.'?5+q/~g/day respectively (group C).Transiliec bone biopsy was performed before and af ter 6-11 months treatment.14 biopsies showed lesions of mixed variety(OM+ff)and I had prevalent 0M.Group A showed R slower normalization of serum Ca than groups B and C,hyperphosphate mia was difficult to contro1,mean iPTH did not chRnge.Dsteoid surface.thickness and volume decreased while only in 1 case resorption surface decreased.Calcified bone volume did not change.Group 6 showed a decrease in AP and iPTH in 4/6 cases. Osteoid surface decreased in 5 / 6 cases while the osteoid volume decreased in 4/6.However in 5 cases active osteoblastic surface increa5ed.A decrease in resorption surface was w i d e nt in 3/6 cases.Group C showed reduction of AP and a mean 5oqb drop in iP1H.In all cases marked reduction in active Rnd inaz tive osteoid surfacR,osteoid volume and resorption surface was found.The results indicate that the combined treatment is more effective than the use of single metabolites.Since duri ng the treatment serum 24,25(DH)2D3 levels did not differ (2.9820.13 and 3.71+1.68 ng/ml respectively,M+SD,NS)the effe ct of 250HD3 and 1,2S(OH)2D3 is not due to enhanced synthesis of 24,25(C1H)~D~, but to a synergic action of the two metaboll tes.

Patologica.University of Rome-I taly

193

Artificial Organs 0 .

Vol. 5, No, 2

CASCADE FILTRATION PLASMA PHERESIS

A u t h o r ( s ) : ~ . R . S h e t t i g a r , H . Mann, A . G r e s s n e r

Address:Dept. I n t e r n a l M e d i c i n e 11, U n i v e r s i t y

P l a s m a e x c h a n g e ( P E ) u s i n g e i t h e r m e m b r a n e o r c e l l c e n t r i f u g e s is e x p e c t e d t o b e b e n e f i c i a l i n t h e t r e a t m e n t o f a w i d e v a r i e t y o f t h e b l o o d a b n o r m a l i t y . PE i n v o l v e s m a i n l y t w o s t e p s , n a m e l y (1) s e p a r a t i o n o f p l a s m a f r o m b l o o d a n d ( i i ) r e p l a c e m e n t o f t h e p l a s m a b y a s u b s t l t u - t i o n f l u i d o r p r o c e s s i n y o f t h e p l a s m a t o r e m o v e t l i e " a b n o r m a l m a c r o m o l e c u e s r r f r o m p l a s m a a n d r e - i n f u s i o n o f t h e r e m a i n i g u s e f u l c o m p o n e n t s o f p l a s m a .

The p r e s e n t s t u d y d e a l s w i r h t h e c o n t i n u o u s m e m - b r a n e s e p a r a t i o n o f t h e m a c r o m o l e c u l e s ( s p e c i e s a b o v e 10OODO d a l t o n s ) f r o m p l a s m a . T h i s s t u d y i s m o t i v a t e d b y t h e n e e d t o r e d u c e t h e c o s t a s we l l a s t h e s i d e e f f e c t s i n h e r e n t i n t h e u s a g e o f a s u b s t i t u t i o n f l u i d .

The c o n t i n u o u s s e p a r a t i o n o f p l a s m a f r o m b l o o d was c a r i e d o u t u s i n g a n ASAHI ' P l a s m a f l o ' f i l t e r . The p l a s m a f r o m t h e p l a s m a f l o was r e c i r c u l a t e d t h r o u g h a n A M I C O N HlP lOO h o l l o w - f i b e r f i l t e r t o o b t a i n a f i l t r a t e c o n t a i n i n g t h e u s e f u l s p e c i e s b e l o w l O O O O D d a l t o n f o r t h e r e i n f u s i o n . The s p e - c i s a b o v e 1 0 0 0 0 0 d a l t o n s a c c u m u l a t e i n t h e r e c i r c u l a t i n g - p l a s m a - l o o p . The i n c r e a s i n g a l b u m i n c n n c e n t r a t i o n i n t h e r e c i r c u l a t i n g l o o p was c o m p e n s a t e d by t h e c o n t r o l l e d a d d i t i o n o f a s t e r i l e e l e c t r o l y t e s o l u t i o n .

T h e e f f e c t i v e n e s s o f t h e a b o v e s y s t e m was com- p a r e d w i t h t h a t o f t h e ' D o u b l e f i l t r a t i o n p l a s m a p l i e r e s i s ' s y s t e m w h i c h i n v o l v e s no r e c i r c u l a t i o n o f t h e p l a s m a . The r e c i r c u l a t i o n o f p l a s m a h e l p s t i , i n c r e a s e t h e f i l t r a t i o n f l u x by b r e a k i n g t h e e f f e c t i v e n e s s p o l a r i z a t i o n i n t h e f i l t e r . T h e e f f e c t i v e n e s s o f t h e a b o v e sys t em w e r e d e t e r m i n e d i n t e r m s o f c l e a r a n c e o f I g A , I g G , IgM f r o m b l o o d a n d r e c o v e r y o f a l b u m i n f o r t h e r e i n f u s i o n .

A a c h e n , C o e t h e s t r . 2 7 / 2 9 , 5 1 0 0 A a c h e n

A scin 1 ra i c t e hni u e f o r t h e ~ i f u ~ l i z a f i f & , g f i ~ ~ y $ ~ ~ & ~ i o n p o f a h z 8 ; o n phenoaena i n p o s t 1 u iona

Authorls): Hemoli B . , Ca lde ra ro V . , Drioli E . , S a l v a t o r e M., Bazzicalupo L . and Andreucci V . E .

Address: Cha i r of Nephrology, 2nd Facu l ty o f Medicine, U n i - v e r s i t y of Naples - I t a l y . Treatment o f c h r o n i c uremia by h e m o f i l t r a t i o n has been shown t o be b e t t e r t o l e r a t e d than d i a l y s i s : a n improved c o n t r o l of s a l t and water balance and a dec reased i n t r a d i a l y t i c morb id i - t y r e p r e s e n t a v a l u a b l e development of d i a l y s i s technology. A p r o g r e s s i v e r educ t ion of u l t ra f i l t ra te f l u x e s d u r i n g t h e t r e a t m e n t c o n s t i t u t e s i t s main l imi t . Th i s i s due t o an i n - c r e a s i n g plasma p r o t e i n c o n c e n t r a t i o n on t h e p r e s s u r i z e d s i - de o f the membrane due t o concentration p o l a r i z a t i o n phenome- n a . I n a p rev ious s t u d y we ana lyzed t h e k i n e t i c s o f t h e pheno menon emphasizing t h e role o f plasma p r o t e i n concentration a t t h e membrane-solution interface and t h e changes o f t h e f l u o d y namic due t o t h e h e m o f i l t e r internal structure. A commercial RP 610 h e m o f i l t e r has been used i n t h i s s t u d y . The p r e s e n t pape r conce rns t h e v i s u a l i z a t i o n o f t h e phenomenon by a gam- ma camera connected on l ine t o a computer . The ana lys i s of t h e t r a n s i e n t s and of t h e s t e a d y s ta te has been c a r r i e d o u t , i n v i t r o , f o r pe r iods o f time s i m i l a r t o a s t anda rd c l i n i c a l procedure. Th i s method al lowed us t o v i s u a l i z e the p r o t e i n concentration d i s t r i b u t i o n on t h e p r e s s u r i z e d s i d e o f t h e me! brane and i t s changes w i t h time, a long bo th a x i s o f t h e sys - tem. There fo re , we were a b l e t o i d e n t i f y t h o s e r e g i o n s o f t h e h e m o f i l t e r less e f f e c t i v e i n t h e u l t r a f i l t r a t i o n . Our d a t a re s u l t e d compa t ib l e wi th t h e mathematical model o f t h e ge l t h e g r y . A comparison wi th a n a l y t i c a l model which take i n t o acco- u n t a l so t h e i n t e r f a c i a l osmotic effects i s p r e s e n t e d .

Title: USE OF GORE-TEX CRAWS AS VASCULAR ACCESS PROCEDURE FOR CHRONIC HWODIALYSIS

Authorls):. C h a t t e r j e e . S a t y a N.

Address:4301 X S t r e e t , Sacramento, CA 95817, U.S.A.

One o f t h e most d i f f i c u l t problems i n t h e c a s e of d i a l y s i s p a t i e n t s i s t o g u a r a n t e e a t r o u b l e - f r e e v a s c u l a r a c c e s s . The c o n t i n u i n g appea rance o f r e p o r t s o f new g r a f t s f o r access p rocedures p roves t h a t none is r e a l l y s a t i s f a c t o r y . I n i t i a l r e p o r t s o n new materials are a lways e n t h u s i a s t i c b u t on ly t h e pas sage of t i m e r e v e a l s t h e compl i ca t ions and d i s s a t i s f a c t i o n s . The p r e s e n t s tudy e v a l u a t e s patency and c o m p l i c a t i o n s among 36 Gore-Tex g r a f t s i n s e r t e d be tveen November, 1978 t o February, 1981 i n 33 p a t i e n t s on d i a l y s i s . P a t i e n t p r o f i l e s were: Male 40% and Female 60%; D i a b e t i c s 27%; smokers 33%. non-smokers 67%; age d i s t r i b u t i o n 10-29 years-11%, 30-49 years-22%, 50-69 years-67%. Mean age was 53.39 y e a r s . Twenty-five g r a f t s (70%) were placed i n t h e upper arm. f i v e i n t h e t h i g h and s i x i n t h e forearm. A l l g r a f t s were 6.0 m s t r a i g h t f i s t u l a s . A l l g r a f t s i n t h e upper arms were c a r r i e d o u t u s i n g a x i l l a r y b lock . Pro- p h y l a c t i c a n t i b i o t i c s were n o t used. s u t u r e d w i t h 6-0 p r o l e n e s u t u r e s and a l l anastomoses w e r e end-to-side. w i th 14 gauge need le s . C u m u l a t i v e pa t ency by l i f e t a b l e a n a l y s i s a t 30 months was 8 4 5 7% S.E. due t o c l o t t i n g and one g r a f t was t aken o u t due t o i n f e c t i o n S t e n o s i s of t h e runof f v e i n , b l e e d i n g , pseudoaneurysm, s e p s i s and s k i n u l c e r a t i o n were n o t s een i n t h i s series. I n s p i t e of hav ing a p r o p o r t i o n a t e l y l a r g e r number of high- r i s k p a t i e n t s ( d i a b e t i c s and > 50 y e a r s o f age) i n t h e p r e s e n t series, t h e r e s u l t s a r e f a r s u p e r i o r compared t o our ear l ier d i s a p p o i n t i n g e x p e r i e n c e w i t h Bovine g r a f t s and saphenous v e i n g r a f t s . l m a t e r i a l i s a v a i l a b l e , Core-Tex g r a f t should b e used f o r v a s c u l a r access i n d i a l y s i s p a t i e n t s .

The g r a f t s were

A l l g r a f t s were e a n n u l a t e d t h r e e t i m e s a week

Three g r a f t s f a i l e d

U n t i l such t ime when improved

'Payne, C h a t t e r j z e , Barbour , Berne: A . J . S . 128:54, 1974.

Urea sodium and w a t e r removal du r ing haemodia lys i s Title: and t h e i r r e l e v a n c e t o hypovoiaemia: a computer simu-

l a t i o n Author(s):A. E. 0. Lewis and T. H .Fros t

Deoartment o f Mechanical Enqineer inq. Un ive r s i t v Address: o f ' Newcastle upon Tyne, Engiand and-Sekt ion Nephre l o g i e , U n i v e r s i t a t U l m , S t e i n h o v e l s t r a O e 9 , 73 Ulm, BRO

Bergstrom and o t h e r s have demons t r a t ed t h a t v a s c u l a r s t a b i l i - t y d u r i n g h a e m o f i l t r a t i o n is s i g n i f i c a n t l y b e t t e r t h a n d u r i q haernodialysis and t h e obvious d i f f e r e n c e between t h e methods i s t h e d i f f u s i v e loss o f s o l u t e s d u r i n g haemodialysis and t h e r e s u l t i n g d e c r e a s e i n plasma o s m o l a l i t y . Rouby et a]. have c a l c u l a t e d t h e plasma r e f i l l i n g rate from t h e d i f f e r e n c e between u l t r a f i l t r a t i o n rate and changes i n plasma volume. A s imple computer model o f plasma r e f i l l i n g has been cons t ruc - t e d t o f i t t h e i r d a t a and i t was shown t h a t changes i n t h e s o l u b l e p r o t e i n c o n c e n t r a t i o n i n t h e in ters t i t ia l pool could i n t e r f e r e w i t h r e f i l l i n g b u t solute changes had no d i r e c t i w f l u e n c e . I t was t h e n proposed t h a t solute removal increases c e l l volume t h u s d e p l e t i n g t h e i n t e r s t i t i a l f l u i d , i n c r e a s i n g i t s o n c o t i c s t r e n g t h and r e t a r d i n g r e f i l l i n g . A computer model of cel l volume c o n t r o l under s t e a d y s t a t e c o n d i t i o n s was c o n s t r u c t e d and t h i s showed t h a t u l t r a f i l t r a t i o n a l o n e or removal o f urea o r 100 mV KCl from t h e system had ve ry small e f f e c t s on c e l l volume b u t s i g n i f i c a n t s w e l l i n g was caused by t h e removal of 160 mY of NaCl ( e q u i v a l e n t t o a plasma t o d i a l y s a t e g r a d i e n t of 5 mtV1 and d i a l y s a n c e o f 133 m l / m i n f o r 4 hours b u t exc lud ing i s o t o n i c NaCl removal by u l t r a f i l - t r a t i o n l . The e x t r a c e l l u l a r sodium c o n c e n t r a t i o n was expec ted t o d e c r e a s e by 14 M l b u t t h e NaCl remaining i n t h e e x t r a - c e l l u l a r pool was f o r c e d i n t o a smaller volume and dec reased by o n l y 1 . 5 mH/l. T h i s l e a d s t o t h e f a l s e impression t h a t s i g n i f i c a n t d i f f u s i v e loss o f sodium does n o t occur . I t i s concluded t h a t d i f f u s i v e sodium removal i s cons ide rab ly more impor t an t t han d e c r e a s i n g o s m o l a l i t y and t h i s i s suppor t ed by t h e f i n d i n g s o f van S t o n e et a l . who showed t h a t maintenance o f c o n s t a n t plasma o s m o l a l i t y by a d d i t i o n o f g l y c e r a l t o r e p l a c e urea d i d n o t improve v a s c u l a r s t a b i l i t y . The use o f i sona t r i c d i a l y s a t e shou ld e l i m i n a t e d i f f u s i v e sodium removal r e s u l t i n g i n improved v a s c u l a r s t a b i l i t y . S t e w a r t and N . K.Man have a1 r eady r e p o r t e d improved v a s c u l a r s t a b i 1 i t y and reduced symptoms u s i n g i s o n a t r i c d i a l y s a t e and t h e t ech - n ique i s used r o u t i n e l y i n Ulm.

194


Elimination-characteristics of high-concen- Title: t r a t e d IgM by hol low-f ibre plasmapheresis f i l -

AuthoW: Euler ,H.-H. , Gutschmidt , H . J . * , Address: 2nd Medical Dept. of t h e Univers i ty ofKiel

We examined t h e elimination-characteristics o f IgM of a serum c o n t a i n i n g 87 ,2 g / l IgM ( p a r a p r o t e i n ) by

ho l low-f ibre membrane p lasmapheres i s f i l t e r s ( A s a h i PF 0 1 ) . The IgM-concentrat ions and t h e whole p r o t e - in -conten t were measured i n t h e course of 3 hours every 10 minutes a t t h e a r t e r i a l , venous and a t the f i l t ra te -compar tment ( e l e c t r o p h o r e s i s , q u a n t i t a t i v e immunodiffusion, laser -nephelometry) . The f i l t r a t i o n - f l o w diminished from 50 m l / m i n a t the beginning t o 1 1 m l / m i n ( 3 h ) . The IgM-concen- t r a t i o n i n :he blood diminished from 8720 mg/dl t o 4760 mg/dl. The f i l t r a t e conta ined 6050 mg/dl IgM a t t h e beginning, 3 h l a t e r 2100 mg/dl. T o t a l l y we removed 3 , % 1 o f f i l t r a t e conta in ing 185 g IgM wi th in 3 hours without compli 'cat ions. These d a t a show, t h a t i t is p o s s i b l e t o e l i m i n a t e molecules as b i g a s IgM (MW 960.000) even a t high c o n c e n t r a t i o n s . There i s a diminuat ion of t h e f i l - t r a t i o n - f l o w , probably caused by p a r t i a l c l o t t i n g of t h e pores . B u t even a f t e r 3 h cont inous plasma- p h e r e s i s t h e r e i s s t i l l a s a t i s f y i n g f i l t r a t i o n - capacity f o r IgM.

t e r s .

H e r r l i n g e r , J . D . , Kokenge,F., L o f f l e r , H .

' Intensiv-Care Unit,Town-Hospital of Kie l

SOME PHYSIOPATIdOLOSICAL CONSIDERATIONS ASOUT T , ~ I ~ ' T H E RBSPTRATORY FIJNCTJONAL CHANGES D U R I N G HE

Address Department of Nephrology and Dialysis .Gen. Rea.Hosp. Lecce ( I t a l y )

The r e s p i r a t o r y f u n c t i o n a l chanqes d u r i n g HD,which might be v a r i o u s l y e x p l a i n e d ( a c i d 0 s i s r e c o v e r y , D C O ~ and p02 changes , uremic t o x i n s d e p u r a t i o n , h y d r o s a l i n e b a 1 a n c i n g ) a r e w e l l known.We have s t u d i e d t h e ro le of t h e s e f a c t o r s : t h e lung f u n c t i o n have been e v a l u a t e d i n 23 p a t i e n t s by Spi rograph H P 9825A(tes t s performed:FVC,FEVl,FEVl/FVC,FEFP-l,2; FEF25-75,FF,MEF SO%,MEF 75%,MIF 5 0 % , V t , R R , E R V . I C . VC) ; ac id-base b a l a n c e , BUN,serum c r e a t i n i n e and 2 l e c t r o l y t e s have been e v a l u a t e d i n t h e same p a t i e l l t s . T e s t s have been per formed: l )Refore and a f t e r s t a n d a r d HD;2)Sefore and a f t e r i s o l a t e u l t r a f i l t r a t i o n ( V F ) ; j ) SePore and a f t e r H D without body weight changes.Resul ts :UF improves FVC.FEVl,ERV.PF,VC(wL t h p u t pH,HCOj,p02 and 7UN changes).HD wi thout UF does n o t improvez r e s p i r a t o r y f u n c t i o n a l t e s t s . 0 n e may deduce t h a t t h e o v e r h y d r a t i o n i s t h e c a u s e of r e s p i r a t o r y d e f i c i t i n t h e uremic p a t i e n t s i n c h r g n i c HD.

0 . THE KINETICS OF Ca++ D U R I N G ACETATE AND X C A E

T~%ONATE DIALYSIS.

Author(s):Mastranqelo F.,Manisco G. ,De 31asi V . , A L fonso L . . R i z z e l l i s . . c o r l i a n d C . , A p r i l e M.,%ongL Address: o r n o E Montinaro A.Department O f Nephrolg

qy and Dialysi;.Gen.Req . H o w .Lecce( I t a l y ) Bicarbonate d i a l y s i s ( 8 D ) i n comparison t o a c e t a t e d i a l y s i s ( A D ) c a u s e s t h e s e r e s u 1 t s : l ) A b e t t e r i n t e r and i n t r a d i a l y t i c s t e a d i n e s s of blood P H ; Z ) A more comple te c o r r e c t i o n of a c i d o s i s . T h e n , a d i f f e r e n t Ca++ k i n e t i c s and consequent r e p e r c u s s i o n s on Ca- P metabolism and bone a r e conceivable .Fo1lowing n-u d i e s d u r i n g 2 y e a r s have been performed i n 40 pa t i e n t s c r o n i c a l l y d i a l y z e d ( 2 5 i n AD.15 i n RD):1) Longi tudina l researches(Ca-P ba lance ,PTH.a lka l ine

phosphatase ,ac id-base b a l a n c e , e t c . ) ; 2 ) C a + + i n t r a d i a l y t i c k ine t ics :Ca++ i n t r a d i a l y t i c fZowE(C,- and Ca+* removal indez from e x t r a c e l l u l a r space

k c p = D ( c D - C , o - G e l h a v e been examined a t v a r i a

s is of bone minera l c o n t e n t w i t h 112' densi thome try.Results:Ca:; i n 9D i s lower than Ca$+ in AD, m a j n t a i n i n g a b e t t e r d i a l y t i c g r a d i e n t ; i n 9D t h e r e i s an i - n t r a d i a l y t i c Ca++ e a r n i n g v e r s u s AD;bone m l n e r a l c o n t e n t i n BD does n o t vary .Conclus ions : i t i s p o s s i b l e t h a t . i n BD,lower CaD++ a l l o w s ga in of

Ca++ a s i n AD and h i g h e r CaD++ c o u l d g i v e a b e t t e r g a i n , b u t be dangerous.

l e b i c a r b o n a t e ??ria Ca++ r a t e i n d i a y s a t e ; 3 ) A n a l y

REFRACTARY ASCTTES I N HEMODI ALYSTS( HD J : C O M S l Title: NED HD WITH ASCIT FLUID(AF)CONCENTRATTON AND

RETNFIISTON.

l i a n b c

I d i o p a t h i c a s c i t e s h a s been o c c a s i o n a l l y observed a s a v e r y c o m p l i c a t i o n i n p a t i e n t s i n r e g u l a r HD. Various t h e r a p e u t i c m o d a l i t i p s have been a t tempted , w i t h i ;npredic tab le and d i s a p p o i b t i n g r e s u l t s . T h e r( d u c t i o n of t h e a s c i tes i s p r o b l e m a t i c a l .because Of v a r i a b i l i t y induced by HE on t h e s p l a n c h n i c a l c a p i lary h y d r o s t a t i c p r e s s u r e and t h e o n c o t i c p r e s s n r e o f t h e AF.The p a r a c e n t ~ s j s , m o r e o v e r , c a u s ~ s p r o f u s e p r o t e i n 10ss.W~ h a v e r e a l i z e d a system which allow c o n c e n t r a t j o n and r e i n f u s i o n of t h e AF d u r i n g HD by means of t h e same d i a l y z e r . T h e AF h a s been s e c k e d from t h e abdominal c a v i t y and l e t i n t h e a r t s r i o u s l i n e a f t e r t h e beginninq of t h e HD-The u l t r d f i l t r a t i o n ( l 1 F ) h a s been a d j u s t e d so t h a t t h e concen t r a t i o n OF t h e 9F r e i n t r o d u c e d were h igh .Dia lyzer5 i n PAN have been u t i l i z e d t o r e a c h a r a p i d and h i g h UF.3 l i t res of AF have been a v e r a g e l y concen t r a t e d and r e i n f u s e d during each d i a l y t i c s e s s i o n . T h i s t e c h n i c , w e l l t o l e r a t e d by p a t i e n t s , a l l o w e d t h e r e d u c t i o n of t h e AF and a n increment of t h e plasma p r o t e i n s , a v o i d i n g problems of c a r d i a c high- o u t p u t .

A u t h o r ( s ) : ~ ~ a c , t r ~ n a ~ ~ o F. I R i z z e l l i s . , AI f o n q o L . ,c:oc Aaaress:'Department of Nephroloqy and D i a l y q i s .

Gen. Reo. H o s p i t a l L e c c e ( 1 t a l v )

195


AWUT THE NECHANISMS OF DIALYSIS RELATED HYPO T i t l e : XEMIA.

Author(s):Mastrangelo F..Alfonso L. .Corlianb C.,Riz telli S.,De Slasi V.,Aprile M.,%onqiorno E..Monti Addressnaro A. Department of Ne hroiogy and Dialy u e g . GPn . Hosp . Lecce I talyP bebate continues on the mechanisms of hemodialysis (HD)induced hypoxemia.It is a matter of controversy whether hypocapnic hypoventilation or acute pulmg nary dysfunction induced by HD is responsible.In order to elucidate the pathogenesis,following invg stigations were carried out during the first hour and hourly thereafter in 2 groups of patients dia lyzed with acetate or bicarbonate + COz in the dia lysate(D1):f)Lung function studies by Spirograph HP9825A;2)Blood gas ana1ysis;3)pC02 in dialysate. The two groups differed in the pC02 in DL.The first group shows a significant mean pC02 gradient betwe en arterial(33.6 mmHg)and venous(21 mmHg)lines and DL inlet and outlet,shoving an important C02 traE sfer from blood to DL.There is a Fall in p02 in ths first hour too.The second group shows little chac ges in pC02 a-v gradient(35-42),but exhibits an equal state in pO2.We conclude that hyporemia and hypocapnia are unrelated phenomena.

A C'RITTCAL ANALYSIS OF ACETATE ANT) 3ICARsoNc Ti'le:TE DI4LYSIS.

Author(s)MaStrarlgelo F.,AlFonso L.,Corlianh C.,De .,Rizzelli S.,Nanisco G., rh~ongiorno F.,Apri

Addressle M,Department of Nephrology and Dialysi 5 .

~eq. HosDital Lecce I1ta1.v) Aicarbonate dialysis(BD;? years of treatment)versu acetate dialysis(AD;Z years of treatment)have been carried out in 1.5 patients.New devices(0TE BTOMEDL CA).which a l l o w a single pass dialysis by 2 rot5 ting pwnps.were ntilizad.The Following problems ha ve been eramined:l)EfFect OF dialysate base(DB)on arid-base ba1ance:BD causes a more constant cove ction OF acid0sj.s with stnhjlization of predialy tic acid-base balance at physiologycal level 5.2) Cardiovasciilar effects of D9: ¶ll improves the blood pressure, va xu1 ar s tabi I i t y , t ol erance to rapid u l trafiltration.wel1-being inAex.3)EfFect OF D9 on blood lipids: there i s no si gni Ficant difference in the serum triglycerides and cholesterol concentra tion by the use of the different schedules.4)Eff~ cts of D9 on calcium ba1ance:BD causes a better d i alytic gradient OF Ca++.a better intradialytic cal cium gain and a more steady bone mineral content measured at level of forearm.

~ i t l e : CALCTIIK 'MI.ANCF DITRTITI: CAPD.

Authors) I*.nstr3naelo F.,Mani?co T;.,De 7 1 a P i V.,Cq gnazzb k. .Xaggj iz l l i G.,Alfonso L - , D i Sjlva 4..aiz Z~,$r~s~-Department of Nephrology and Dialyqis.Cen

Total ralciiim and Ca++ kinetics during CAPD have not yet pointed 0ut.Following parameterr.during CAPD,have been eva1uated:Ca Cai+,acid-ba+e bala:

RPq.FOspital Lecce (Italy).

Hc03pF. Ca++9~ntraAialvtic flow

daily gain.These data have been kinetics during acetate(25 pa

tiant s) and bicarhonn te 1 5 patients) hemodi alysi s. Resii1t~:during CAPD,Ca'+ dialytic gain is lower than hmodialysis,thereFore a bone mineral loss could take place without an adequate support thera

Longitudinal studies by hone densithometry with have been carried out in order to show this

phenomenon.

COMPARISON OF AMINOACIDS LOSSES IN 4 HOURS SINGLE

DIALYSIS Title: PASS DIALYSIS AND IN 2HOURS,40 LITERS RECIRCULATING

Author(s': Malrnusi G,Savazzi A.M,Vandelli L Orlandi G,Petrella E',Bigi L',Baraldx A,Capelli G

Renal unit,University of Modena : 'Bellco laboratories, Mirandola, Italy

Pre and p s i d i a l y s i s plasma changes and the losses i n the dia lysate o f SOBE free amino ac ids have been evaluated comparing. i n 10 c l i n i c a l l y siabls f as t i ng

pat ients . 1 hours s ing le pass d i a l y s i s (6 pat.) (SPD) and 2 hours batch r e c i r c u l - a t i ng d i a l y s i s using 40 l i 'kcrs of d ia lysate (4 pa t ) (RD) - In both s t ra teg ies d ia lysate yap qlucose-free, cuprophete of 1 n2 uas used. PB was 280 n l / n i n and QU 500 ml/min. Thp t o t a l removal of anino acids vas gr. 11 f 1.8 i n SPD and gr.1.5 f 0.1 i n Ro. rur thz es ren t ia l amino ac id : [ f A A ) the rcmoval uas gr. 4.5 gr.0.5 f 0.05 i n Ao. For the not essent ia l amino ac ids [NEAA) the removal was

gr.6.6 f 1 i n SPD and gr. 1

The losses o f amino ac ids i s much more c lose ly r e l a t e d t o the amount o f d ia lysate parsed (6'4.976) than to the &rat ion Pre and past d i a l y s i s plasma concentrat ion o f i n d i v i d a l amino ac idr change i n d i f f e r e n t way: i n SPD there i s a decrease [ r ) o f VAL 19 - ILEU 45 - LEU 38 - IHRE 4 3 - M E T 55- LE 28 - TYR 33 - TRIP1 38 and i n increase (I) of AM 16- GLY 20- PRO 16- SER 28- ASP 85- CE 7- GLU 16- DRN 10- PHE 5 2

IP RD there i s a decrease [a o f VAL 31- ILEU 3s LEU 36- THRE 39- HET 23- LYS 15 CYS 1- GLU 7- IYR 1 and an increase (%I of PHE 43- TRlPT 63- ALA P GLY 10- PHO 12- SER 16- ASP 60- ORli 13.

On the whole, EAA decrease of XI% i n SPO and 18 i n R b N E A A increase o f 2a i n SPJ :>I:< 15% i n RO.

In summary the losses o f an% acids are o f 85% less i n RD than i n SPD. ( E M 87% less - NEAA 84% less)

The to ta l mount o f the losses i n RO i s s i m i l a r t o the normal mean da i l y anino ac ids exc re t i on i n man.

0.6 in SPD and

0.1 i n RO.

o f the d i a l y s i s run.

196


FUNDAMENTAL STUDIES ON THE DEVELOPMENT OF A WEARABLE Title: ARTIFICIAL KIDNEY WITH A FILTRATION-ADSORPTION METHOD

Author(s): H.Funakubo K.Shirane, T.Dohi, T.Tagori , A.Takeuchi'. N.Miura*, S .Yoshida**. N.Takai** and T.Inou***

Fac. Eng.4*;ac. Agri .* , I n s t . Ind. Sci.**, I n s t . M e c . S c i . , Univ. Tokyo, 7-3, Hongo, Bunkyo-ku,

Address :

Tokyo, Japan.

A f i l t r a t i o n - a d s o r p t i o n method w i t h con t inuous low f i l - t r a t e f low has been found s u i t a b l e f o r t h e r e a l i z a t i o n of a p r a c t i c a l l y wea rab le a r t i f i c i a l kidney. The main p rocess i n t h i s method is f i l t r a t i o n , and a plasma s e p a r a t o r appea r s t o be s u p e r i o r t o an u l t r a f i l t e r from t h e viewpoint of minia- t u r i z a t i o n . We have designed and manufactured a l l t h e components r equ i r ed f o r a wearab le a r t i f i c i a l kidney employing t h i s method. Tow plasma s e p a r a t o r s , a p a r a l l e l flow t ype and a c y l i n d e r t y p e , have been c o n s t r u c t e d us ing a Nuclepore Membrane wi th a po re - s i ze of 0.6pmm, and a s t a b l e f i l t r a t e flow of about 7mllmin h a s been ob ta ined .

The f i l t r a t e t r e a t m e n t system c o n s i s t s of a n u l t r a f i l t e r , a u r e a s e column, a c a t i o n exchange column, an a c t i v a t e d a lu - mina column, a c t i v a t e d c h a r c o a l column, a n e l e c t r o d i a l y z e r and s e v e r a l micro-pumps. In this system, u rea is hydrolyzed i n t o ammonia by immobilized u r e a s e and r e p l a c e d by sodium i n the ion exchange t r ea tmen t . The excess sodium is then removed by t h e e l e c t r o d i a l y z e r .

The system formed by assembling t h e s e components h a s been shown by expr r imen t s i n v i t r o t o f u n c t i o n i n a s a t i s f a c t o r y manner as a wearab le a r t i f i c i a l kidney. The t o t a l weight of t h i s t r i a l a p p a r a t u s , i n c l u d i n g t h e b a t t e r y , can be reduced t o l e s s t han 5kg.

Title: D I C i ' O C A C L E t!E;tTI-'tl? FOR D I A L Y S I S F L U I D

Au,hor(s):Or land i n i G . , P e t r e l 1 t i o € ~ , U i ! j i L . , C a l a r i o h .

Rerlrl U n i t , U n i v e r s i t y of I.:otien; - I l a S y z O D E 1 ~c o L ~ L o r a t o i r c s , ;.li r ;no o 1 -- ~t a 1 y

A u i s p o s a b l e u e v i c c f o r lheat lng d i a l y s i s f l u i d has t e e n des igned and c r e a t e d f o l l o w i n g r e s e a r e l l c P r = r l e d o u t i n t o an a i ;oararus i o r haer , iod ia lys i s uh ich i s p o r t a b l e , ~ d a p t a b l e t o v e r i o u s d i c . l y s i s teChni= q u e s ( r e g e n e r a t i o n , r e c i r c u l z t i o n , s i n g l e i,i.s5), of s i p l e s ~ r u c t u r e ;nd easy i8ianageiiient. f o r use rnywhe.re anti vhicl l 1125 h d i s p o s a L l e d i n l y s a t e c i r = c u i t . It c o n s i s t s o f c V-shaped tube i n 2 ~ o o d c o n d u c t i n m a t e r i a l ; i t i s e l e c t r i c a l l y c o n n e c t e d i n s e r i e s t t h e secondary winding of an AC t r t n s i o r i a e r ; i t f u n c t i o n s a t t h e same t ime b o t h a s c patlli-ay f o r - t h e d i a l y s i s f l u i d i t s e l f 2.5 c e l l a s h e a t i n c e l e = ment f o r t h e s a m e f l u i c i . T e n p e r a t u r e i s r e g u l i t e c i b y two probes which a r e not a c t u e l l y i n contz-ct w i t h t h e f l u i d , t u t which can be coi,!pared t o k e i t s e n s n r s t h a t p i l o t a t h e r o o r e g u l a t o r connected ' to t h e p r i m a r y winding of t h e t r&ns?Orl~ ler . The h e g t h e r has been i n s e r t e d i n t o a neWly-deviSed machine f o r d i n l y s i s a n d lics a l r e e d y been used i n o v e r 2000 l i i iemodialysis runs. w i t h most s a t i s f a c t o ry r e s u l t s .

A simplified method of plasmapheresis therapy Title: Technique and f i r s t resul ts

Author@): Rolf BAMBAUER and Gus tav Adolf JUTZLER Department of Nephrology (Director: Prof.Dr.med.

Address: G . A . JUTZLER) of the Med.Univ.-Klinik D-6650 Homburg/W-Germany

W i t h t h e i n t r o d u c t i o n o f h o l l o w - f i b e r membranes f o r p l a s m a s e p a r a t i o n , t h i s t r e a t m e n t has rece ived world-wide r e c o g n i t o n . There a r e a l r e a d y numerous c a s e - r e p o r t s i n which p lasmapheres i s as symptomatic t h e r a p y , combined wi th c o n s e r v a t i v e t h e r a p y , i s d e s c r i b e d a s very promising i n i t s r e s u l t s . P r e r e q u i s i t e f o r t h i s method o f t r e a t - ment , however, i s a very e l a b o r a t e a n d expens ive hemof i 1 t r a t i on-sys tem.

We a r e r e p o r t i n g about our own e x p e r i e n c e s with a t e c h n i c a l l y s i m p l e sys tem, which o p e r a t e s e q u a l l y s a f e and e f f e c t i v e a s t h e o t h e r machines p r e s e n t - l y used. Our system c o n s i s t s of a double-head blood-pump, a s u b s t i t u t i o n - p u m p , a p l a t e - t y p e h e a t e r f o r warming t h e s u b s t i t u t i o n - s o l u t i o n a n d t h e h o l l o w - f i b e r p l a s m a s e p a r a t o r ; we a r e using t h e "single-needle"-technique. For b l o o d a c c e s s , e i t h e r J u g . i n t . v e i n or S u b c l . v e i n i s punctured and by means of S e l d i n g e r - t e c h n i q u e a c a t h e t e r of l a r g e gauge i s i n s e r t e d . The c a t h e t e r remains i n s i t u f o r t h e e n t i r e phase o f t r e a t m e n t s e r i e s By means of t h i s method we have t r e a t e d p a t i e n t s w i t h L u p u s e ry thematodes , p o l y r a d i c u l i t i s a s p a r a n e o p l a s i a o f a b r o n c h i a l - c a r c i n o m a , c h r o n i c r e j e c t i o n of kidney t r a n s p l a n t s , plasmocytoma, p r o g r e s s i v e musce l -dys t rophie and hemolyt ic- uremic - syndrom e . The f u n c t i o n of our s i m p l i f i e d system i s d e s c r i - bed a n d r e s u l t s of t h e p lasmapheres i s t r e a t m e n t s a r e p r e s e n t e d . We could show, t h a t t h i s m e t h o d of t r e a t m e n t i s s a f e , can be c o n t r o l l e d i n d i v i d u a l l y a n d i s well s u i t e d f o r mobile use anywhere.

0 . THEORETICAL EVALUATION OF THE CLEARANCE K

EETRY. Title: WITH REFERENCE TO A MASS EXCHANGER GEO-

Author(s).Andrzej Zamecznik, h!aciej Zborowski , Address: I n s t . o f B i o c y b e r n e t i c s and Biomedica l

E n g i n e e r i n g , P.A.S., Warsaw, Poland.

T h e r e are s e v e r a l m a s s transfer models o f a h e m o d i a l y z e r , i n which o n l y a n a v e - rage membrane p r o p e r t i e s and the b l o o d a n d t h e d i a l y s i s b a t h f l o w r a t e s , Q. and QD , r e s p e c t i v e l y , are c o n s i d e r e d ; h o w e v e r , t h e y do n o t e x p l a i n some e x p e r i m e n t a l l y obser - ved d i f f e r e n c e s In I(, e v a l u a t e d f o r t h e h e m o d i a l y z e r s d i f f e r i n g i n t h e membrane s u p p o r t geornetry.Here t h e i n f l u e n c e o f t h e f l u i d v e l o c i t y on t h e t o t a l membrane p l u s boundary l a y e r p e r m e a b i l i t y P w a s assumed t o b e of the form P = k.% where v-velo- c i t y at t h e membrane s u r f a c e , n-normal t o the l a t t e r , k - c o n s t a n t . T h a t w a s a p p l i e d t o a model o f a membrane mass e x c h a n g e r ( f l a t plate d i a l y z e r ) b a s e d on the equa- t i o n o f a gross m a s s b a l a n c e i n e v e r y c r o s s - s e c t i o n o f t h e d i a l y z e r , w h i c h y i e l d e t h e K as a f u n c t i o n o f : Qs and Q D ,u l t ra- f i l t r a t i o n r a t e Qr ,membrane p e r m e a b i l i t y P, and t h e membrane t o t a l s u r f a c e , r e - f l e c t i o n c o e f f i c i e n t d a n d t h e d e p t h t o w i d t h r a t i o of t h e d i a l y s i s b a t h c h a n n e l s . The t h e o r e t i c a l l y p r e d i c t e d v a l u e s o f K compare w e l l w i t h t h e p r e l i m i n a r y e x p e r i - m e n t a l r e su l t s f rom our l a b o r a t o r y .

197

Artificial Organs

CWINED HEldODIALYSXS-!iEMOPeF@PWION ALLOWS

OF TREATMENI! I N RET PATIEWS. Author(s): Ste fon i S. ,Fe l i c i ange l i G. ,Cali L. ,Busca-

r o l i A.,Scolari M.P. and Bonomini V. Address: I s t i t u t e of Nephrology and Dia lys i s .

University of Bologna.

Title: MAIKED REDDCTION ( l /3 ) OF THE WEH[LY HOURS

The capac i ty of charcoal t o absorb endogenous and exogenous t o x i n s i s wel l established. It removes substances o f h igher molecular w e i g h t with respec t t o standard d i a l y s i s membranes. The r egu la r use of charcoal hemoperfusion (HP) as an adjunct t o hemo- d i a l y s i s (HD) i n RDT i s the re fo re of r a t i o n a l p e r spec t ive va lue e i t h e r f o r improving t h e p a t i e n t ' s c l i n i c a l and l abora to ry conditions and/or f o r reducing t h e weekly t ime of treatment. F ive consent- ing informed p a t i e n t s on RDT from 9 t o 35 months ( r e s idua l GPR 0-1.8 ml/mn, mean d i u r e s i s 350 m l ) have been t r e a t e d without i n t e r r u p t i o n f o r 5-8 mo_n t h s according t o a schedule inc luding two combined HD-HP procedures ( t o t a l hours per week:8) i n s t ead of t h e previous 3 HD se s s ions ( t o t a l hours pe r week:12). P a t i e n t s were on adequate d i a l y s i s and t h e i r c l i n i c a l , metabolic and labora torg condi t ions were s tab le . In t h e HE-HP procedure a ca r t r idge conta in ing 1 5 0 g of methacrylate-coated ac t iva t ed charcoal with high b iocompat ib i l i ty w a s i n s e r t e d i n t h e d i a l y s i s c i r c u i t i n s e r i e s with a f l a t pla- t e o r hollow f i b e r d ia lyzer . C l in i ca l , l abo ra to ry and metabolic condi t ions remained unchanged i n all p a t i e n t s desp i t e t h e l / 3 reduction of d i a l y s i s hours per week. The to l e rance of treatment w a s good: p l a t e l e t s , white c e l l s and f ibr inogen were unaffec- ted. The marked reduct ion o f weekly t ime of t r e a t - ment l e d t o a more e a t i s f a c t o r y pa t i en t s ' personal and s o c i a l r e h a b i l i t a t i o n , enabling more p a t i e n t s t o be t r e a t e d w i t h t h e same f a c i l i t i e s .

Tille: IMPROVEXEITTS I N BONE MARROW UNDER CONTINUOUS AMBlRATORY PERIMNEAL DIALYSIS (CAPD)

Author($): H. Becker, B. Bombik, R . Schurig, G.M. Gahl and

Address: Fi. Kessel. Freie Universi t a t Berlin, K 1 inikum Char lo t tenburg, Berlin-West, FRG.

Five pat ients with end-stage renal disease were analysed before and a f t e r 12 months of CAPD (selected blood parame- t e r s i n table I ) .

before CAPD a f t e r 12 months mean SD mean SD

Rrmglobin

Fe r r i t i n 487,O +262,0 178,O 2143,O Hemtocri t 2:;; ; ;:; 2;:; ; 2:: (30-150 ng/ml) Vitamin B12 552,O +285,0 631,O 2 78,O (300-1000 ,pg!ml) Erythropoietin 5,4 3,5 8,8 % 6 , 4 (7-36 M.I.U./ml) Numbers in parentheses: n o m l range.

Detai ls of bone marrow a re fol1owing:l. Reduced m u n t of r e t i cu l in f ibers ,2 . Normalized fat content,3. Reduced iron content,4. Increased number of plasma ce l l s ,5 . Improved megacaryopoiesis,6. No changes i n granulopoiesis,7, No sig- n i f i can t changes i n erythropoiesis. After 1 2 months of CAPD there a re moderate improvements of the bone marrow, red c e l l mass and hemoglobin. The reduction of plasma f e r r i t i n corresponds t o the reduction of iron in the bone mrrow because of increased use for the synthesis of hanoglobin. Al- though &re was no impressing improvement i n the erythropc- i e s i s , the c e l l u l a r i t y of the bone marrow had improved a s can be seen a l s o on the reduction of r e t i cu l in f ibe r s and f a t . The cause could be the steady s t a t e of the uremic substances on a lower l eve l during CAD instead of inter- mit tent intoxicat ion due to intermittent d i a lys i s such a s in I P D or hemodialysis.

Vol. 5, No. 2 0 .

INCREASED MAXIMUM HAEMOFILTRATION RATES I N A T i t l e ' VORTEX-MIXING HAEMOFILTER

Author(s): M. A. J e f f r e e , J. Peacock and I . J . Sobey

Address; Oxford U n i v e r s i t y , Department of Eng inee r ing Sc ience . Pa rks Road, Oxford, United Kingdom.

I n a h a e m o f i l t e r employing v o r t e x mixing. t h e maximum u l t r a f i l t r a t i o n r a t e (&!.,I o b t a i n e d w a s e i g h t t i m e s a s h igh a s t h e maximum o b t a i n e d i n t h e same d e v i c e w i t h o u t v o r t e x mixing.

During h a e m o f i l t r a t i o n , u l t r a f i l t r a t i o n r a t e s (UFR) a r e slow and i t h a s been obse rved t h a t when h i g h l y perme3ble membranes a r e used t h e UFR r e a c h e s a maximum which is i ndependen t of transmembrane p r e s s u r e (AP,). Higher UFRS a r e p reven ted by p r o t e i n c o n c e n t r a t i b n p o l a r i z a t i o n and p r o t e i n g e l l a y e r fo rma t ion nea r t h e membrane s u r f a c e . I n s t e a d y flow d e v i c e s the e f f e c t s o f p r o t e i n c o n c e n t r a t i o n p o l a r i z a t i o n have been r educed by i n c r e a s i n g t h e s h e a r rate n e a r t h e membrane s u r f a c e , e i t h e r by i n c r e a s i n g blood f low r a t e o r by d e c r e a s i n g t h e b l o o d channe l gap . Blood f low r a t e . however, 1s p a t i e n t l i m i t e d and d e c r e a s i n g t h e gap below 160pm produces no f u r t h e r i n c r e a s e i n UFR.

AS an a l t e r n a t i v e approach , i n a vortex-mixing haemofi l ter we have i n c r e a s e d QFM by employing r e v e r s i n g p u l s a t i l e flow over a furrowed membrane s u r f a c e .

Using p o l y a c r y l o n i t r i l e membrane (AN69) we achieved a maximum h a e m o f i l t r a t i o n r a t e l Q F M ) of 165ml/min/m' w i th v o r t e x mixing, compared w i t h OFM o f 18ml/min/m' w i thou t v o r t e x mixing. t o t a l plasma p r o t e i n s 8 3 g / L ) .

(Qb300ml/min/m', APm6Q0Wg. H C T 28%.

No r e d u c t i o n i n UFR w i t h t ime was obse rved Over a run of f i v e h o u r s .

The QFM ach ieved w i t h v o r t e x mixing was 34% h i g h e r t h a n t h e h i g h e s t v a l u e p r e v i o u s l y r e p o r t e d w i t h t h i s membrane, and would make h a e m o f i l t r a t i o n c l e a r a n c e s h i g h e r , o r t r e a t - ment t i m e s s h o r t e r .

W e have a l s o s t u d i e d t h e e f f e c t s of v o r t e x mixing du r ing membrane p l a smapheres i s and have ob ta ined s i m i l a r i n c r e a s e s i n f i l t r a t i o n r a t e s .

REDUCED VASCULAR STRESS A ~ L J t l I G - I TOLEI<ANCE TO llilCi.iDDYALISIS

L a r a l d i A o , U a s s i S o o , C i c i L o o o , C r a n d i F n o , Author(s) capL,e 11 i ij 0 , c a s t e 1 I a n i A O 0 , Lona t 1 F 0 0 , L u= Address: S V J ~ 9 li i E O ,6:a l rou s i iio , u r 1 anti 1 r i i L o , I'e t r e 1=

12 E o o o , P o i a t t i P o o , S h v d z z l h O , V L n d e l l i L o Renal U n i t , U n i v e r s i t y of Modenil, I t a l y . 1:enal U n i t , Uinoerto lo Hosb. , d r e s c i a , I t a l y .

O o 0 E e l l c o L z t o r a t o i r e s , i.iirL;ndola ( . .10) , I tnly.

The o b j e c t i v e of this s t u d y w a s t o o b t a i n a n i m = provement o f t t ie d i a l y t i c t o l e r c n c e i n a Groub of p a t i e n t s who f r e q u e n t l y l aan i f e s t ed c l i n i c a l d i s o r = d e r s d u r i n ~ j c o n v e n t i o n a l d i a l y s i s . The Study was conduc ted on 7 G t s . ( 2 a n u r i c , 5 w i t h c r . c l . 4 2 m l / m i n ) linvinr, unde rgone p r i o r s i n g l e - , . a s s t r e a t m e n t f o r o v e r 6 Isontiis; t h r i c e weekly f o r 4 h r s . , 1 SLI.

m. cup rophane f i l t e r s , d i a l y a a t e c o n t a i n i n g Na 1 3 - 140 , I< 0-2, C 1 103, A c e t a t e 3S, i.ig 1 -1 .5 , C a 4 i i i E q , l . , g l u c o s e 0-1 g:.,a(SUI. For t t l e p a s t 4-13 iiioriths t h e s e same [its. l i avc been p l a c e d on s c l i & l y s i s s c h e d u l e of 2-2.5 h r s e v e r y o t h e r day w i t l i t h e sa= me f i l t e r s and r e c i r c u l a t y n g d i a l y s a t e (40 I t . ) , c o n t a i n i n g Nn 135-138, K 0-4, B i c a r l ~ o n z t e 35, Ace% t a t e 10, C 1 07 niEq/l, S l u c o s e 0 (USNO). T h e f r e = quency G i f f e r e n c e of c l i n i c i l A c c i d e n t s between 370 SD. arld 475 USRU was: V O I i I T I I J G (13. 2;; SD; 1. l:i U S R D ) - C O L L A P S E ( 1 L . 9:: SD; 0. a:, USRl;) - CtWiPS (12.7:- SD; ! ~ . 9 USIIU) - HEAUACI-IE (17.L." S O ; O.C:, USRD) - A H I i Y T i A I A (4.3:; SLi; 0.2 : . USRD).

The iimproved t o l e r a n c e in s p i t e of a uoub le u l = t r a f i l t r a t i o n (USl:U 15 .6 ml/ioin; bD C.3 i w l / i w i n ) liL: ve i ~ o s t l i k s l y been c a u s e d by v a r i o u s f s c t o r s : ri'= duced o s i , i o l n r i t y (-3O:+), niinii8icl rei , loval of c a t e = cho la r , i i nes (-6%;) a n d s u b s t i t u t i o n of a c e t h t e witl, b i c a r b o n a t e i n t h e d i a l y s a t e .

198


SINGLE-PASS DIALYSIS W I T H E I C A R E O N A T E : ACID-EASE BALANCE A N D TOLERANCE TO DIALYSIS Title:

Author(s): Orlanc l in i G . , E r o g n o l i i.'.., Rontiinz I.;. ,Za= n e b o n i A . , O P e t r e l l a E . , ODi5i-L.

Address: R e n a l U n i t , , Leno-!-lanerbio Iiosp. ( C r e s c i a , I T . ) - OUellco Labornt . , I . ; i c a t l o l a ( IT_)

IJowadeys 2 renewed i n t e r e s t h z s beeri d e d i c z t e d t o t h e t i i a l y s j s b a t h c o n t e n t : olti and ncv; c r i t i c i s i n have ernergr.6 as t o t h e u s e of a c e t a t e and nuinerous a r e t h e p r o p o s a l s i n f a v o r of i t s s u u s t i t u t i o n w i t h b i c a r b o n n t e , i n o r d e r t o pmprove t o l e r a n c e t o d i a l y s i s . Ve liave deve loped a s imple a n d e f f i c i e n t method f o r proport ionp.1 p r e p a r a t i o n of c o n t i n u o s b i c a r b o n a t e d i c l y s a t e , by ; ,#akin3 use of two sepa= r a t e s a l i n e s t a b l e c o n c e n t r a t e s o l u t i o n s : ~ l l t h e d i n l y s z t e l i n e s a r e s t e r i l e and d i s p o s a b l e a f t e r use . E i g h t pts. who f r e q u e n t l y mani fes ted c l i n i c a l d i = s o r d e r s d u r i n g c o n v e n t i o n a l a i e t a t e (35-12 r,iEq/l) o ' i a l y s i s ( t r e a t e d more t h a n s i x rhontl3s. c r . c l . < 2 m l / m i n ) undergone t r e a t m e n t , f o r o v e r s i x i.ionttls, u s i n g s i n g l e - p a s s b i c a r ~ o n a ~ e t i i i l y s a t e (P:=+ ~ Z T , l K * l , C k 4 , I: iG*l. 5 , C1-107-99, tZ0, 27-35, CH3COO- 10, g l u c o s e O ) , k e e p i n g t o t h e same sci ieoule (4iirs x 3 t i m e s x w e e k ) . C l i n i c a l e v - l u - t i o n s e r e under= :iay f o r a y e a r now: more than 1000 haernodiolgses . Most of t h e p t s . p rove how a s e n s i b l e c h a n s c i n t h e ac id-base e q u i l i b r i u m o b t a i n e d t h r o u p h t h e x i = d o s i s c o r r e c t i o n c a n r e s u l t i n a n o t a b l e improve=

ment o i t h e d i a l y s i s s y n t o n s . S c a r s e o r a t h e r i n a p = p r e c i e b l e r e s u l t s seems t o be o b t a i n e d \:.lien t h e d i a l y t i c d i s c o r , i f o r t s a r e n o t a s s o c i z t e d . to shzr i ) d i s t u r b a n c e s o f t h e aci t i -base %$lar ice .

~ i ~ l ~ : PET:O1;AL V E X C.4TIIETERISATIOI!: AS t h e b e s t

Author(S t e r m h e m o d i a l y s i s .

Address: $@&gp&?2gs,Dept. Nephrol . and D i a l y s i s ,

second c h o i s e f o r the v a s c u l a r access o f l o n g

d&kuzan , I I . and P e y n i r c i o z l u , S .

S e l d i n g e r ' s method i s u s e d i n 902 f e m o r a l v e i n c a t h e t e r i c a t i o n s i n 39 c a s e s w i t h r e n a l f a i l u r e ( R " ) - 1 2 a c u t e and 27 c h r o n i c . D u r i n g 4 5 1 h e r n o d i a l y s i s t r e a t m e n t s t h e mean b l o o d flow was 2 0 9 C 86 m l / m i n ( r a n g e s 100-400 ml/min) . Ho c o m p l i c a t i o n s were o b s e r v e d i n a c u t e c a s e s . I lhere i n c h r o n i c p a t i e n t s f e m o r a l hematoma occured only in one p a t i e n t ( s O . 1 1 ) and subcu- t a n e u s f i b r o u s t i s s u e development occured i n two p a t i e n t s ( : J 0 . 2 2 ) a f t e r 210 and 126 v e n i p u - n c t u r e s r e s p e c t i v e l y . Three o f o u r c h r o n i c pa t ien ts r e c e i v e d t r a n s p l a n t k i d n e y s and it was o b s e r v e d t h a t t h e i r v . c a v a i n f . and common i l i a c veins were n o t t r a u m a t i s e d . These p a t i - e n t s were c a t h e t e r i z e d 210, 58 and 56 t imes r e s p e c t i v e l y . I t i s s u g g e s t e d t h a t S e l d i n g e r ' s method a p a r t f rom t h e a c u t e c a s e s c a n be use f o r a long p e r i o d i n c h r o n i c p a t i e n t s nho were w a i t i n g for r e n a l t r a n s p l a n t a t i o n w i t h f a i l e d i n t e r n a l A-V fistulas and a l s o i n p a t i e n t s who were wai';?ng f o r de-Je lopnent o f good f u n c t i o - n i n g i n t e r n a l f i s t u l a .

Title: Insertion of Tenckhoff's Catheter: notes on a particular technique.

Author(s) F . T E S I 0 , E - G I A N O L I , G.?hNxXLLO, E.CECCHIN, k . ? . . N E E T E R

Address: OSPEDALE CIVILE, 3 5 l 7 O I-CRDENONE, ITALY

With the scope of insertion of the Tenckhoff catheter as a means o f access t o the peritoneal cavity, we. -refer the surgical method by laparotomy since th i s permits an evalu- ative exploration o f the peritoneal cavity a n d a iiore pre- c i se placement of the catheter. In time, however, this may undergo displacement a n d be obstructed by omentum, therecore to avoid complications which frequently occur, numerous modifications to the shape of the catheter have been studied. A solution to avoid these problems which has been adopted by th i s Center, i s a simple change in the technique of position- i n g the standard catheter. T h i s change was suggested following five years of experience, during whiah we have noted a dis t inct reduction of complications: during this time 52 catheters were inserted, of which the major part are s t i l l functional.

~ ~ f i ~ : Six Years of Experience of Transplants Using Preserved Saphenous Veins as a Vascular Access for Hemodialysis.

Author(s): F. T E S I O , E. G I A N O L I , C. C A N U R R I ,

Address: Ospedale C iv i l e , 33170 Pordenone , I t a l y P. Q U A I A , A. RAIPjONDI

With considerablv increased frequency it has become necessary t o m a k e use of a r t i f i c i a l or organic prostheses t o prepare t h e vascular access f o r hemodialysis. The prostheses used most often a t t h e p r e s e n t time are bovine carotids, segments i n PTFE, and transplants of homologous vein.

For six years t h i s Center has been using segments of saphenous vein vithdraun during the course of surgical operations for varices, vhich are preserved by a par t icular method and used for transplants even a year a f te r extraction, without t a k i n g theABO compat ib i l i ty i n t o account.

42 t ransplan ts have been performed, 5 bovine caro t ids have been inserted, and 14 prostheses i n PTFE.

Review of t h e resu l t s obta ined a n d a comparison w i t h o t h e r methods used have encouraged u s t o present our par t icular method of preservation and preparation for t r a n s p l a n t , w i t h emphasis on t h e simplicity of performance, t h e absence of immunological reaction, the rapid u t i l i z a t i o n of t h e f i s tu la and t h e excellent' functional resul ts . L a s t , b u t certainly not l e a s t , the very l o w cost and ready supply of the graf t material.

199

Artificial Organs Vol. 5, No. 2 0 .

HIGH PERFORMANCE POST-DILUTION HEMOFILTRATION (HF):A Title: SAFER AND MORE EFFICIENT TREATMENT OF UREMIA THAN HEMC

Author(s): G.Civati,C.Guastoni.A.Perego,U.Teatini.M.L.Broggi and L.Minetti

Address: Renal Unit,Ca' Granda Hospital-Milan (Italy) The difficulty to achieve small molecular clearances (C) cop! parable to those obtained in HD was an obstacle to a wide di ffusion of HF.1n HF urea clearance (C) is strictly related to plasma filtration fraction (FF=Q /Q 1 and independent of substitution method (pre;pre-post;p!stP.The highest FF is al ways obtained in postdilution HF.According to these d ta we used Jwo,hollow-fiber hemofilters in series,lst 0.6 m 2nd 1.2 m ,with postdilution method,in two chronic patients:we performed in each patient 3 seances of 4 hours with a weight loss of 3 kgs. Patients : 1st 2nd Ht % 20 36

nIpLysxs (HD) .

2

Plasma Proteins g/dl 7 . 1 7 . 2 ml/min 500210 500210

Trans-Membrane pressure mm Hg 450230 450230

Mean Urea C ml/min 194.4219.7 148.5221.9 Mean Creat. C ml/min 196 -2224.1 148.6221.6 Mean Phosphates C ml/min 162.7215.9 146.3219.4 Mean Ultrafiltration rate ml/min 176.4215.5 140.6115.4

Total Urea removal g 49.921.3 4 4 . 5 2 0 . 9

Total Phosphates removal mg 1080+92 767242.7

Total Ultrafiltrate L 40.621.5 33.620.6

Mean FF : 0.460+0.03 0.45420.03 The post dilution,if high FF are obtained,is better than pre and pre-post di1ution;this technique can achieve in a comparable time higher small molecular C than HD without clinical signs of intolerance and can be employed in acute and chronic patients .

QB

Total Creat. removal g 2.9L0.15 1 . 9 + 0 . 1 -

0

Tit,e: SELECTION OF OPTIMAL CAPILLARY INTERNAL DIAMETER

Author(s): IN. J .Lysaght ,'C.A.Ford, 3K.A.Isaacson 'Pax Planck Institute for Biophysics, Frankfurt,

AddreSs:FRG; PAmicon Carp, Lexington, MA USA; 3Dept Chem Eng, MIT, Cambridge YA USA

IN BLOOD ULTRAFILTERS

A series of ultrafilters was constructed from protien- retentive, anisotropic polysulfone hollow fibers whose luminal diameters ranged from 200u to llOOu , Ultra- filtration rates were measured in-vitro with CPD anti- coagulated whole blood (WCT - 2-0 c. rate varied from 250 to 1900 Sec - l ; device area from 0.01 to 1.0 M2. independent plateau region. At conditions of fixed blood flow rate, representative of

the pumped circuits in conventional chronic hemofiltration, device filtration per unit area was found to decrease in inverse linear proportion to fiber radius. D m n t e n d - ed for such usage should accordingly be designed with the smallest fiber diameter consistent with tolerable pressure drops and levels of anticoagulant. In contrast, in unpumped circuits with fixed end-to-end pressure gradients but variable blood flow rates (which condition obtains in Arterio-Venous or "spontaneous" hernofiltration, in most "wearable" configurations, and in certain single fiber designs being advanced for endogonous pancreas replacement) rate of filtration increased with the square root of fiber diameter. the conventional 200~ are indicated. These results are quantitatively consistent with the

thin film theory of macromo~ecu~ar concentration polarization and can readily be extrapolated to predict the effects of channel height in parallel plate ultrafilters.

Wall shear

Data was always collected in the pressure

Fo-vices, diameters in excess of

Tit1e:ADDING OF BRONINE TO DIALYSATE TO IMPROVE QUALITY OF SLF,EP OF PATIENTS ON HAEMODIALYSIS

Author(s):P.L.Oe, R.D.Vis, J.H.Meijer, F.v.Langevelde. W.Allon, C.v.d.Meer and H.Verheu1

Address: Academic Hospital and Institute of Physics, Free University, Amsterdam, The Netherlands

A significant correlation between bromine deficiency and the quality of sleep in patients on haemodialysis was found. The purpose of the present study was to investigate the effect of adding bromine to dialysate in order to correct bromine depletion and to correlate this correction with improvement of quality of sleep.

placebo) to dialysate was performed. Four stable patients, undergoing twice ueekly maintenance haemodialysis for at least one year, successfully completed the study. The quality of sleep was determined by a recog- nised interview technique as used in evaluating hyp- notics in out-patients. The bromine concentration in serum before haemodialysis was determined according to the technique of proton-induced X-ray emission. In the first ten weeks NaBr or NaCl was added to correct the concentration in the dialysate to 25 pmol/l. In the next ten weeks the concentration in dialysate was doubled.

Adding NaBr to the dialysate in two patients re- sulted in a significant improvement in the quality of sleep, accompanied by increased bromine concentrations in serum. Adding of NaCl to the dialysate in two patients did not improve the quality of sleep, accompanied by unchanged bromine concentrations in serum. The quality of sleep of patients with the addition of NaBr to the dialysate was better than that of patients with the addition of NaCl to the dialysate. There wa6 no difference in quality of sleep both between the two patients receiving NaBr and between the two patients receiving NaC1.

due to removal of bromine by the dialyser, is the cause of insomnia in patients on chronic haemodialysis.

A double-blind study of adding NaBr or NaCl (as

There is strong evidence, that bromine deficiency,

0 . CEARACTEHISTICS OF A NEW HIGH FLUX MEMBRANE PLASlJlASEPxRATOR - ELIMINATION OF IMMUNE Title:

Author(s):Glockner, d.lvI. , Dienst,C., COMPLEXES. Modder,G., Hahnp . , Sieberth,H.G.

Address : Medizin.Universitatsk1inik Koln, \/.Germany

Plasma exchange by plasmafiltration with hollow fibre plasmaseparators has been shown to be effective i n treatment of immunological diseases, but it is handicapped by the necessity of a high blood flow and the partial reflection of plasma protein molecules at the membrane. We therefore tested a new plasmaseparator with improved characteristics, the Plasmaflo HI 05 from the Asahi Medical Comp. Tokyo.

and thereby increased filtrate flow rate ttis module can be used with the low veno-venous blood flow (55 ml/min + 25 ml filtrate/min).

increased too:

marker : albumin transferrin ferritin (mol.weight) (69000) ( 9 0 0 0 0 ) (560.000j

sieving coeff. : 0.97 0 . 9 5 0 . 9 0

Due to its reduced membrane thickness (75,um)

The permeability of the filter is significantly

1 gc IgM immune gompl. LDL ( i5aooo) (9oo.000) ( 1x10 ) ( 2 . 5 x 1 0 6 )

0 . 9 9 0 . 7 3 0 .92 0.82

These results demonstrate the improved characteristics of the tested new plasmaseparator, especially the increased elimination of high- molecular immune complexes.

200

Communications 0 .

ORAL ANTIPLATELET AGENT INDOBUFEN (K 3920) AND REGULAR DIALYSIS TREATMENT (RDT) . Title :

Author(s):Albertazzi A., Spisni C., Lembo N., Cappelli P.

Address: Nephr. & Dialysis Dept. - University of Chieti - ITALY

The cuprophan membrane when it comes in contact with blood results in the deposition of platelets and fibrin on its surface reducing dialysis efficiency. Heparin prevents gross clotting in the extracorporeal circuit but has little effect or exacerbates platelet activation and may expose the patient to risk of haemorrhage.

We studied the effect of a new antiplatelet agent on heparin dosage during dialysis and on the performance of dialyzers. Indobufen 200 mg/day p.0. was administered to 20 uraemic pts on RDT for I5 days. During treatment heparin was reduced by 20%. Before and after treatment we examined: BUN, creatinine, uric acid, cholesterol, triglycerides, VLDL, alkaline phosphatase, bilirubin, SGOT, SGPT, LDH; RBC, Hb, PCV, reticulocytes, WBC; platelet counts, aggregation induced by AOP 0.8-2 gmol. (according to Born) with determination of slope and reaction time, adhesiveness (according to Hellem), and dripping time. Before and during treatment we also controlled: BUN, creatinine and uric acid clearances of dialyzers and blood rest.

aggregation with prolungation o f slope and reaction time; dripping time was also increased, but no haemorrhage was observed; platelet counts increased as RBC, Hb, PCV and reticulocytes. The clearances improved significantly with a concomitant reduction in BUN, creatinine and uric acid; a decrease in triglycerides and VLDL was also noted.

allowing a reduction of heparin dosage and increasing dialysis efficacy without any imoortant side-effects.

Indobufen induced a reduction in platelet adhesiveness and

Antiplatelet indobufen has a positive effect in RDT pts

Title: The e f f e c t of haemodia lys i s (HD) on lymphocyte E

Author@) :

Address: P. MIOSSEC

r o s e t t e f u n c t i o n (ERF)

J. CLEDES, P . Y O U I N O U , Ph. LEGW, J. P. HERVE

C . H . R . MORVAN 29279 BREST CEDEX FRANCE

The e f f e c t o f HD ( 3 weekly s e s s i o n s of 5 h r s , p a r a l l e l p l a t e k idney , 11.5/cc, Im2) on ERF ( J F Bach's t echn ique ) was s t u d i e d b y two expe r imen t s .

I - Decrease a f ERF i s i n f u n c t i o n t o the d u r a t i o n of HD

( t a b l e below)

ERF % Durat ion (ms) Dura t ion (ms) renal f a i l u r e haemodia lys i s '

Cont ro l s (50) 68.5(56-79)a 0 0 Group 1 (10) 65.8(58-74)a 59.0(5-136)a 17.3(2-4O)a Group 2 (10) 51 .5(34-57)d 78.4(29-154)a 40.5(4-60)c Group 3 (10) 53.9(40-57)d 117.2(60-224)b 85.0(40-13h)d

-

mean, ( r a n g e ) - a b C 0 . 0 5 , a c C 0 . 0 2 , ad = c d ~ 0 . 0 0 1

The d e f i c i t of p a t i e n t s i n the second group i s r e v e r s i - b l e by i n c u b a t i o n i n normal plasma. Th i s effect i s due t o a p l a s m a t i c f a c t o r s i n c e t h e ERF o f normal lymphocytes is reduced by the p a t i e n t ' s plasma.

2 - The f a c t o r i s n o t d i a l y s a b l e a s a f t e r a d i a l y s e session the Z o f i s a g a i n reduced, t h i s - b c o r r e l a t e d t o t h e + A i n t h e i n h i b i t i o n of t h e plasma on the ERF Df normal lymphocytes (y = - 0 . 6 3 x + 8,79 ; n = 2 3 ; r = 0.58 ; p 0.01)

Cuprophane membrane Seems t h e r e f o r e t o have an e f f e c t on t he r e c e p t o r s t o sheep r e d blood c e l l s .

0 .

CARNI'I'INE SUPPLEMENTATION I N PATIENTS O N RE- GULAF DIALYTIC TREATMENT (RDT) ,SERUM L I P I D S A N D ((AGULATION-FIBRINOLYSTS PARAMETERS.

Author(s):PPLLA R . . G I U S T I R . ,BENSI L . ,MJ.RCHITIELI,O

Address: C l i n i c a M e d i c a 1 1 - C a t t e d r a E n d o c r i n o l o g i a

H i g h t r i g l g c e r i d e ( T C ) -*-d or low h i g h d e n s i t y l i p 0 - p r o t e i n - c hc 1 e s t e r o 1 1 e v e 1 s ( HDL-CH ) a r e p r ed omi n a n t l i p i d a l t e r a t i o n s i n p a t i e n t s w i t h e n d - s t a g e r e n a l f a i l u r e and RDT.. T h e s e f i n d i r g s a r e c o n s i d e r e d t o b e t h e m a i n r i s k f a c t o r s f o r a t h e r o g e n e s i s a n d a d e q u a t e t r e a t m e n t i s n e c e s s a r y , h u t d i e t a r y a n d p h a r m a c o l o g i c a l t r i a l s a - r e o f t e n d i f f i c u l t t o p e r f o r m d u e t o t h e l o w c o m p l i a n c e o f t h e p a t i e n t s .

S u p p l e m e n t a t i o n o f c a r n i t i n e was c l a i m e d t o q u i c 11" i m D r o v e ( 2 w e e k s ) l i p i d a l t e r a t i o n s i n RDT p a - t i e n t s .

8 p t s . i n R D T f o r I t o 8 y e a r s w i t h h i g h TG l e - v e l s ( 6 216; 2 0 m g / d l ) , n o r m a l t o t a l c h o l e s t e r o l ( C H ) ( m 2 1 8 ~ 30 s & / d l ) a n d l o w l e v e l s o f HDL-CH ( m 3175 mg/dl) w e r e s t u d i e d a n d t r e a t e d by a d m i n i s t e r i n g D - L c a r n i t i n e i n a d a i l y o r a l d o s e o f 2 . 5 g.

C o a g u l a t i v e - f i b r i n o l y t i c s y s t e m w a s i n v e s t i g a t e d by f i b r i n o g e n ( F I ) .F V I I 1 , p l a - m i n o n e n ( P L ) , a n t i t h r o m b i n I I I ( A T 111) p l a s m a l e v e l d e t e r m i n a t i o n s .

O r a l c a r r - i t i n e d i d n ' t s i g n i f i c a n t l y r e d u c e s e r u m TG a t 1 an6 2 w e e k s o f t r e a t m e n t ( m 216r20 v s . l 9 ?

T 1 2 a t l w r r > k , v s . 2 2 3 Z 5 a t 2 w e e k s ) n o r m o d i f y C H , B D L - C H , F V: T I , a n d AT 111 c o n c e n t r a t i o n l e v e l s .

T h e F I l e v e l s h o w e d a n i n c r e a s e a f t e r 1 week ( 5 2 4 5 7 3 0 v : ; . f i 3 0 2 1 1 5 m g / d l ; P = O . O ? ) . h u t a t , t h e e n d o f 2 w e e k s i ' e t o u r n e d t o b a s a l 1 e v e l . P L l e v e l showed a c o n s t a n t d e c r e a s e d u r i n g t r e a t m e n t (15 2 . 1 k T 0 . 6 R . C . U . / m l . . : : .1.9T0.7 ar. 1 w e e k , v s . l . 2 Z O . h a t 2 w e e k s P=O . 0 0 5 ) .

O u r r e s u l t s a r e i n c o n t r a s t w i t h p r e v i o u s r e p o r - t s a n d sug[:c .s t t h a t a c a r e f u l e v a l u a t i o n o f c a r n i t i n e t h e r a p y r i u s t b e c a r r i e d o u t d u e t o b e h a v i o u r O f

F I a n d P L : e v e l s .

M . E . ,NAVALESI R .

S p e r i m e n t h l e . U n i v e r s i t l d i P i s a . P i s a - I t a l y

Title: NEUROELECTROPHY S I OLDGY IN LONG-TERM D I ALY ZED PATIENTS.

Author(s):Di Paolo B. ,Gambi 0. ,Rossini P.H. and Albertazzi A.

Address:Nephrology and Neurology Depts. - University of Chieti - ITALY

Our studies concerning peripheral and central neuropathy are founded on the formulation that in patients with severe renal failure the brain perceives and generates the clinical uremic symptoms.

Computerized electrophysiologic measures of certain brain and peripheral nerve function showed impairments that para1 leled progressive deterioration of renal function and improved subsequent maintenance dialysis(RDT) .The assessment included 5 standardized tests, periodically repeated:Electro- myography (EflG) with computerized analysis of spectral array, flax and Min Motor Nerve Conduction Velocity (MNCV), Sensorial Nerve Conduction Velocity (SNCV), EEG with Berg's analysis, Pattern Reversal Visual Evoked Potentials (VEPs).

periods of diet treatment ( 2 2 t 8 mths') and after starting RDT (33.8 ? 9 mths').

EllG showed deterioration with no change after RDT.However, we found higher amplitude and shorter Motor Action Potentials, associated with a dramatic improvement of the Fast Fourier Transform spectrum. Both the flax and Min tlNCVs decreased in about 40% of our diet pts did not change significantly after RDT. However, RDT improved the lowest SNCVs.

Increased VEPs latencies in diet pts were ameliorated after RDT. EEG data (band frequency spectral analysis) revealed a decrease in brain background rhythm in diet pts and increased activity in RDT pts.

We conclude that electrophysiologic indices support the importance of early evaluation of nervous system function. The steady aggravation of polyneuropathy in RDT could suggest the advisability of renal transplantation.

Neurophysiologic follow-ups were obtained in 15 pts during

20 1


~ i t l ~ : HJGH EFFICIENCY C O N C U R R E N T HEMODIALYSIS D U R I N G CARDIOPULMONARY BYPASS

Author(.): PALLA R . ,MARCHITIELLO M . E . ,GIUSTI R . . SALVATORE L?

Address: C 1 i n i c a M ed i c a I I - C 1 i n i c a C h i r u r g i c a+ Un i v e r s i t a d i P i s a . P i s a - I t a l y

P a t i e n t s o n c h r o n i c d i a l y ' i c t r e a t m e n t ( C D T ) a r e zxposed t o m a j o r s u r g i c a l p r o c e d u r e s w i t h i n c r e a s i - .>g f r e q u e n c y . T h e n e c e s s i t y o f a v i g o r o u s h e m o d i a l y - s i s t o c o r r e c t t h e u r e m i c i m b a l a n c e s p r i o r t o s u r g e r y i s w e l l known b u t t h e d i a l y t i c t r e a t m e n t i s o f t - e n d i f f i c u l t t o p e r f o r m i n p a t i e n t s whose c a r d i a c f u n c t i o n i s c o m p r o m i s e d .

We s u c c e s s f u l l y p e r f o r m e d h e m o d i a l y s i s i n t h e c o - l r s e o f c a r d i o p u l m o n a r y b y p a s s by u s i n g t h e m e c h a n i :n l pump o f b y p a s s c i r c u i t a s mean o f d i a l y s i s .

I n a p a t i e n t w i t h m i t r a l s t e n o s i s and c h r o n i c r e - in1 f a i l u r e ( o n C D T ) , d u r i n g v a l v e r e p l a c e m e n t s u r g e - y , h e m o d i a l y s i s was p e r f o r m e d w i t h a H o s p a l s i n g l e l a s s d e l i v e r y s y s t e m and t w o H o s p a l D i s s c a p (1 sqm s a c h ) d i a l y z e r s c o n n e c t e d i n p a r a l l e l .

Blood was removed f r o m t h e o x i g e n a t o r and r e i n f u - jed i n t o t h e f i l t e r - r e s e r v o i r .

T h i s method a l l o w e d v e r y h i g h b l o o d f l u x e s ( Q B 5 0 0 n l / m i n ) and c r e a t i n i n e c l e a r a n c e v a l u e s o f 3 0 0 mll n i n . D i a l y s i s w a s c a r r i e d o u t f o r 1 5 o f t h e 85- minu- , e s of t h e b y p a s s p e r i o d . L a b o r a t o r y d a t a a t t h e end , f s u r g e r y showed serum c r e a t i n i n e o f 2 .7 m g l d l ( f r ,m 7 . 7 m g l d l a t t h e s t a r t o f d i a l y s i s ( S . D . ) , s e r u m ( + 3.1 m E q / i , h e m a t o c r i t 30% ( f r o m 312 S.D.).

T h e c o n c u r r e n t i n t r a o p e r a t i v e d i a l y s i s p r o v i d e s i n e x c e l l e n t mean t o c o n t r o l : - ) H y p a r k a l i e m i a ; - ) E x - . r a c e l l u l a r f l u i d volume ( a v o i d i n g t h e c e n t r i f u g a t i ,n o f d i l u t e d b l o o d u s e d i n t h e p r i m i n g o f t h e o x i - j e n a t o r ) ;-Remocoagulative-platelet d e f e c t s of u r e m i

F u r t h e m o r e , t h e n e x t d i a l y s i s may b e d e l a y e d , ( i n ) u r p a t i e n t u n t i l t h e t h i r d p o s t - o p e r a t i v e d a y ) a v o i d i n g t h e p r o b l e m o f a n t i c o a g u l a t i o n a n d h y p o t e n s i - r e e p i s o d e s o c c u r r i n g i n t h e s e p a t i e n t s .

Title: T r e a t m e n t of the h e r o i n w i t h d r a w a l s y n d r o m e

Author(s):RusSo L., D e l hlanso F., Russo A.X., R o b e r t i F., B u r z a M.

Address: "HU pins L borstory" C d k d i f icerone

by H a e m o - A n a d i a f i l t r a t i o n (H-ADF)

00045 G e n z a n o (Roma)

Molecular p h y s i o l o g y o f p h y s i c a l d e p e n d e n c e o n h e r o i n and o f w i t h d r a w a l s y n d r o m e is s t i l l unhg wn i n i t s p r o f o u n d mechanisms. Some substances have been s u p p o s e d t o m e d i a t e the a b s t i n e n c e s y n d r o m e w h i c h i s the m a j o r o b s t a c l e t o the s o l u t i o n o f the s o c i a l p r o b l e m . H-ADF i s a v a r i a t i o n o f b l o o d d i a f i l t r a t i o n i n v o l v ing a preventive high d i l u t i o n o f b l o o d ( f o r the d e t a c h m e n t of weakly b o u n d m i d d l e m o l e c u l e s ) a n d a f i l t r a t i o n t h r o u g h a h igh p e r m e a b i l i t y f i L t e r . W e have t r e a t e d a y o u n g p a t i e n t , h e r o i n a d -

d i c t , by e x t r a c o r p o r e a l H-ADF f o r the d e p l e t i o n o f e v e n t u a l t o x i c m i d d l e m o l e c u l e s pre.,ent i n p l a - sma. The p a t i e n t , a 21 years o l d b o y , was a d d i c t e d a p p r o x i m a t e l y t o a s s u m e 300mg o f h e r o i n every d a y f o r s e v e r a l years ,usual ly i n 3 d o s e s . One s h o r t

the a s s u m p t i o n o f the morning d o s e . T h e p a t i e n t d i d n o t present any w i t h d r a w a l s y n d r o m i . Ur n e c - d e d non w o r e h e r o i n i n the same dzy. In the f o l l o w i n g 5 d a y s he c o u l d f u r t h e m o r e l i m i t h i s he- r o i r . assumption t o on lv t w o d o s e s d a y . A s e c o n d 3-N)P ':!as p r o g r a m m e d a t s i x t h d a y , d u r i n g the w i t h d r a w a l s y n d r o m e o f t h e m o r n i n g . E x c e s s i v e excitament o f p a t i e n t d i d n o t al low t o start the p r o c e d u r e . A l t h o u g h a placebo-like mechanism may a l s o b e ig v o l v e d i n such e f f e c t , vie t h i n k that the excretL o n by H-ADF o f p ro t e in b o u n d p o l v p e n t i d e , prove k i n g t he u l t ima te m a n i f e s t a t i o n s o f w i t h d r a w a l s y n d r o m e e x p l a i n b e t t e r the r e s u l t s .

H-ADF ( 6 l i t e r s ) w a s p e r f o r m e d f i v e h o u r s a f t e r

Tit,e:

Author(s):Rus~o L., Mati1.i G . , B u r z a M . , O l i v a d e s e

Address: " H u g g i n s L a b o r a t o r y " G e n z a n o (Roma)

Weakly b o u n d m i d d l e m o l e c u l e s i n uremic p l a s m a a n d v a r i a t i o n w i t h d i a l g z i c t h e r a p j

A , , D e l K a n s o F . , C a r n a b u c i A . , N a r d u c c i C.

S e r v i z i o d i B n o d i e l i s i S t . C a m i l l o H. Roma Uremic plasma have been a n a l y z e d f o r f r e e m i d d l e m o l e c u l e s ( u l t r a f i l t e r a b l e ) a n d w e a k l y b o u n d (7B) m i d d l e molecules ( u l t r a f i l t e r a b l e a f t e r d i l u t i o n ) b e f o r e a n d a f t e r h a e m o d i a l g z i s o r h e m o f i l t r a t i o n , b y c e l - c h r o m a t o { $ r a p h y a n d f l u o r i a e t r i c scan. The r e s u l t s have *how&: - F r e e a n d VIB m i d d l e m o l e c u l e s a r e p r e > e n t i n lax

ce a m o u n t s i n uremia. - The r a t i o f r e e / J B i s v a r i a b l e f r o m p a t i e n t t o

p a t i e n t . - B o t h t y p e r o f t r e a t m e n t l o w e r t h e a m o u n t o f b o t h

f r e e a n d w b m i d d l e m o l e c u l e s , w h i c h remain n e v e r t h e l e s s a t p a t h o l o g i c e l l e v e l s .

- Peaks o f f l u o r e s c e n t m i d d l e m o l e c u l e s r e s i - t t o t he e x c r e t o r y p r o c v d u r e .

T o x i c molecules o f s i r lc le p a t i e n t s s h o u l d b e care f u l l y e v a l u e t e d ( f o r molecular weicht a n d p r o t e i n b i n d i n g ) t o e x e c u t e a s p e c i f i c e x c r e t o r y t e c h n i q u e ( d i a l y s i s , f i l t r a t i o n , a n a f i l t r a t i o n ) .

Title: C l i n i c a l E x p e r i e n c e o f N i n e Y e a r s T r e a t m e n t w i t h H o l l o w F i b e r D i a l y z e r s .

T. D e n n e b e r g , B. J o n s s o n 6 D. M a r t e n s s o n

5-214 01 Malmo, Sweden. Address: D e p t . o f N e p h r o l . , U n i v e r s i t y H o s p i t a l

A t t h e e n d o f t h e ' 6 0 s t h e h o l l o w f i b e r a r t i f i c i a l k i d n e y was d e v e l o p e d . A few y e a r s l a t e r t h i s new d e v i c e w i t h r e g e n e r a t e d c e l l u l o s e membranes (CDAK) was i n t r o d u c e d i n t h e c l i n i c a l f i e l d . T h e s e new k i d n e y s o f f e r e d h i g h e f f i c i e n c y , l a r g e membrane s u r f a c e areas , s m a l l p r i m i n g v o l u m e a n d v a r i a b l e u l t r a f i l t r a t i o n . Our s t u d y r e v i e w s 9 y e a r s e x p e - r i e n c e o f 58 p a t i e n t s ( 2 8 men, 3 0 f e m a l e , a g e 1 0 - 7 3 y r s , mean 47 y r s ) w i t h e n d - s t a g e k i d n e y s . Two t h i r d s g l o m e r u l o - a n d p y e l o n e p h r i t i s . N o d i a b e t i c s T e c h n i u e A r t e r i o - v e n o u s f i s t u l a e . S i n g l e p a s s

T h r e e t imes per w e e k 1976-80. R e s u l t s : T o t a l l y a r o u n d 18000 d i a l y s e s were g i v e n d u r i n g 1734 m o n t h s of t r e a t m e n t . S u r f a c e a r e u s e d , m2 1 . 0 1 . 3 1 . 8 2 . 5 Months o f t r e a t m e n t 194 1 1 1 1 296 1 3 3

*Time o f t r e a t m e n t , H r s / w e e k 1 3 . 5 13 .5 1 4 . 6 14.7 *Body w e i g h t , kg 55 56 78 8 6 * U r e a c l e a r a n c e , QB 200 - 1 5 0 164 1 8 0

& e l i v e r y s y s t e m . Two d i a l y s e s per w e e k 1972-75.

* A v e r a g e v a l u e s The f r e q u e n c y o f blood l e a k s a n d c l o t t i n g of t h e d i a l y z e r s was t r a n s f u s i o n n e e d v e r y l o w , c l i n i c a l l y a n d EMG n o s i g n s o f p o l y n e u r i t i s . 1 0 of 58 p a t i e n t s w e r e p a r a t h y r e o i d e c t o m i z e d . N o o n e had s p o n t a n e o u s f r a c t u r e s g i v i n g d i s a b i l i t y . Today 3 3 % o f t h e p a t i e n t s a r e s t i l l i n m a i n t e n a n c e d i a l y s i s , 47% h a s r e n a l t r a n s p l a n t s and 2 0 % d e a d ( a v e r a g e a g e o f d e a t h 58 y r s ) . I n summary t h i s l o n g t e r m s t u d y shows t h a t t h e h o l l o w f i b e r d i a l y z e r g i v e s e x c e l l e n t r e s u l t s w i t h few c o m p l i c a t i o n s . Today however m o d i f i e d ce l lu lose and a c e t a t e membranes seems t o g i v e e v e n b e t t e r r e s u l t s w i t h h i g h e r c l e a r a n c e v a l u e s w h i c h i s i n c l u d e d i n a s h o r t t i m e s t u d y o f 1 0 o f t h e p a t i e n t s .

202

May 1981

0 .

C0MP;'~ZIATION OF XAD-4 AND COATED CtlARCOdL ENOPEXFD- SION Ili THE TREATbENT OF CLINICAL DIOOXIN IXTOXICA- TIOn

Author(s):R. Sanz, P. Aljama, A. &Malo, R. Perez and

Address: C. S. "Reina Sofia". University of Cordoba. Spain 3. Jimenee-Alonso.

Hemoperfusion (HP) can e f f i c i e n t l y remove digoxin (D) f ro r blood both in v i t r o and in vivo conditiane. Due t o the lack of uniformity i n data presentation, t he re is grea t oonfnsion regarding t h e e f fec t iveness of the m a i n avaib le Hp devices i n c l i n i c a l D tox ic i ty . Moreover because e f t h e unsurmounta- b le d i f f i c u l t i e s of undertaking a cent re1 trial, the aware- noas ef what device should be used w i l l remain based on anec- do ta l c l i n i c a l obsena t ions . We therefore compared the perfo- manoe of ce l lu lose coated charceal (CH) and arnberlite Mw IIP ca r t r idges i n two severe D i n to r i ca t ed pa t ien ts .

Pa t i en t s ingested D attempting suicide. They presented profound abnormalit ies of cardiac rwhm (needing pace-maker) and ex t racard iac s igns of D t o x i c i t y inc luding cen t r a l nem- us system manifestatiens. There w a s a relevant improvement i n patient 's c l i n i c a l p i c tu re and D induced ECC c m e a soon a f t e r HP, suggesting t h a t a s ign i f f i can t mount ef D w a s removed in both instances. Plasma digexin l eve l s decreased st-

d e l y dur ing the procedures. Main r e a u l t s t Clearvrce (ml/m) m r a c t i o n ( 5 ) CH xAD-4 CH

l e t . h; 92 1 i a 46 89 2nd. h. 51 128 26 67 3rd. h. 20 135 12 71 CH produced a mean clearance of 54 m l / m and a mean er trur

t i a n from plasma of 29$, whereas XAD-4 produced 150 m l / m and 75% respectevely throughtout 3 hours of Hp. There Y&Y a decrease of clearance with time suggesting p a r t i a l sa tura t ion of both cartridgss.

We da not propose the indiscriminate use of ID' i n D toxicity, however in l i fe - threa ten ing in toxioa t ion , pa r t i cu la r ly i n those pa t i en t s with rena l f a i l u r e or self-poisoning v i t h large amount e f D, W is an useful therapeut ic adjunct. C n r data s w g e s t t h a t XJUW i s r a the r mmrs e f f i c i en t than CX i n removing D. ?he u6e of a f r e sh ca r t r idge a f t e r t he second hm- ur would seem worthwile i n extremely severe D intoxications, due t o t h e p a r t i a l s a tu ra t ion ef car t r idges .

Title: IS CZLG:idSH DIALYSIS W Y TO BiCALE d ROUTINE

Author(s): A. Martin-Malo, P. dl3ama. R. Sanz, Id. Serraue,

Address: C. S. "Reina Sofia". University of Cordoba. Spain

p a o c m m 7

E. loreno, G. Pdrula and F. Rosal.

Intradialy-tic u l t r a f i l t r a t i o n is of ten troublesome i n dialysis overhydrated pa t i en t s because of the occurence of symptomatic hypotension. A constant plasma osniolality have been aasoc ia ted w i t h a s t ab le blood pressure Yid confortabla weight l o s s curing hemodialyeis, which can be achieve with high-sodium dia lysa te . However, i n t e r d i l y t i c weight gain, hy- pertension and s t imula t ion of t h i r s t o f f se t s t he u l v e n t x e s of high-sodium d ia lys i s . We therofore inves t iga ted the prac- t i c a b i l y and usemlness cf in ta rmi ten t high-sodium d ia lysa t e performing cell-wash d i a l y s i s (CHD) i n pa t l en t s with savera u l t r a f i l t r a t i o n s ide-ef fec ts . d h i g h - f l u Cambro d l a lyse r was used an& 185 mEqjl of sodium d ia lysa t e during 60 m, which w a s lowered t o 135 4 1 for t he same period. 'be two l eve l s of sodium concentration were a l t e r n a t e l y usud hernodialysis with a Dr&e-Willock k a proportionating monitor which w a s e lec t ron ica l ly modified f o r the purpose o f tho s tudy. Results were compared with conventional hernodialysis (CH) using 135 4 1 of sodium, pa t i en t s se rver ing as t h e i r o m controls.

A t t he end of hernodialysis s ign i f i can t ly more f l u i d h$d been removed from the CWD (3 .A .2 Kg) than from CH (2.1-0.4 I[g, p<O.OOl). Blood pressure droped s ign i f i can t ly only durin@ CH 20% of i n i t i a l value p<O.OOl versus 5.3% NS during CHD. Plasma osmolali ty dreascd 1 -2.i NS during CWD and 8.78 p<O.OOl during CII. Observed d i a lys i s complications episodes in ED were 5 6 versus only 18% in 0, p<o.w1. There wan a significant improvement in Hb, phosphate and potasium blood l eve l s during t h e CWD period with normal pred ia lys i s sodium concen- t ra t ions . D-qr weight w a s a a s i ly achieve with no wash-out sym- ptom a f t e r d i a l y s i s ner excesive inges t ion of f l u i d in t e rd i - a lys i s .

It is mg(ps t ed that CUD is a very eas i ly performed procedure with ow? methodology and allows f o r removal of a l a rge r amount of f l u i d whencsnpared t o CH. Be t te r cont ro l of blood chemestry and rrell-being o f pa t i en t s can be achieved, u i t h no problems r e l a t ed to hypernstremia.

during 4 hours

Communications 0 .

Title: HEMODIALYSIS I N SCHIZOPHRENIA

Author(s): G. Sp lendian i , V. Bruno, P. Pomero, M. L . Cammb,

Address:S. Sa lva to re Un ive r s i ty Hospi t a l , L 'Aquila, ITALY M.Tancredi,E.Aquilio.

3 years exper ience i n hemodialysis t reo tment i n s c h i zophrenia ab led us t o s t a t e t h a t sch izophrenic p a t i e n t s could be d iv ided i n t o two g roups : "d io lys i s responders" and " d i a l y s i s non responders".During our t r i a l 25 schi - zophrenic p a t i e n t s were hemodiolyzed wi th polyacr i lon i - t r i l e d io lyzers .The c l i n i c a l resu l t s were eva lua ted w i t h Overa l l and Lorr sca le .At f i r s t t h e d i a l y s i s was performed f o r t h r e e consecut ive days and the cyc le was repea ted a f t e r 1 week,2 weeks,3 weeks,l month and then once a month.If w e do no t cons ide r 9 p a t i e n t s who i n t e r rup ted the t rea tment a t t h e very beginning,of the remai n ing 16,9 showed d isoppeorance o f p s y c h i a t r i c symptoms (Overo l l and Lorr index decreosed f rom 21 t o 2 ) , u h i l e 7 showed no modi f ica t ion of sch izophenic d i s e a s e (no t change o f Overa l l and Lor r i ndex) . A f t e r a month (about 10 d i a l y s i s ) i t i s p o s s i b l e t o p r e d i c t t he e f f ec t iveness of d i a l y s i s t reo tment and t o s e l e c t t h e p a t i e n t s respoc ders.Plasma samples of s ch izophren ic " d i a l y s i s respon- de r s " was t e s t e d by Gel-Cromatography wi th Sephadex G-15.Significant changes were found i n the spectrum of middle molecules subs t ances between schizophrenic and normal blood. I n conclus ion sch izophrenia appears o biochemical d i s e c se respons ive i n s e v e r a l coses t o p o l y a c r i l o n i t r i l e d i z l y s i s t r ea tmen t .

-

Title: MICROCOMPUTER FOR CALCULATION OF INOIVIDUAL DIALYSIS

Author(s): 5 . S t i l l e r , H. Marn

Address:Oept.

PARAME TE AS

In te rna l Medicine, University of Aachen Goethestr. 27/29, 5100 Aachm (GFR)

A desk microcorrputer was programmed to ca lcu la te indivi-

&a1 d ia lys i s parameters such as blood flow, u l t r a f i l -

t r a t ion ra te , d ia lysa te composltion, ard d ia lys i s time on

the basis of cer ta in individual patient & t a . The calcula-

t i ons a re based on a k ine t lc two pool model.

The aim of t h i s p m c e d r e is

-to obtain a su f f i c i en t leve l of de toxi f ica t ion

-to obtain defined concentrations a t the end of d ia lys i s concerning e l ec t ro ly t e s , ac id base parameters and body

f lu id

-to observe individual l i m i t s of m s s t ransfer r a t e s for

water, e l c t ro ly t e s and buf fers

in a minimum o f tune.

In order to achieve t h i s a pa t ien t f i l e containing physio-

logical parameters such a s dry weight, t o t a l body water,

in te rna l mass t ransfer coe f f i c i en t s , a d the individual

l i m i t s of mass excharqe, which can be to le ra ted by the

patient are stored in the mmputer. T h e s e ilata are supple-

mented by actual input LBta such as t h e condition of the

patient before dialysis.

Operating the computer using a keybord and visual display

is eas i ly acconplished by medical s t a f f .

203


ULTRASHORT RECIRCULATION DIALYSIS - REDUCE0 VASCULAR STRESS AN0 H I G H TOLERANCE TO DIALYTIC TREATMENT. Title:

Author(s): GC.' Petrella E.*Poiatti P.-Savarzi AM'Vandelli L.'

Address:

EaraldiA.fEarsiS.~EigiL.*ErandiF.").-Cappelli6.~Orlandini

Ecllco Laboratories SPA - 41037 Mirandola (Modcna) ITALY

Dialysis t Nephrology 0iv.-Un.ty o f Modcna. Italy Bel l co Laboratories SPA - Mirandola. Italy

* Dialysis E Hephrology Service - Umberto 1st Hospital Erescia. ltaly

The objective o f this study was to obtain an improvement o f the dialytic tolerance in a group o f patients who frequently manifested clinical disorders during conventional dialysis.

The study was conducted on 7 patients ( 2 anuric. 5 with c l . c r < 2 . I / .in) having undergone prior single-pass treatment f o r O V ~ P 6 months. thrice weekly f o r 4 hrr. 1 m2 cuprophanc filters. dialyratr containing Na 136-140. K 0-2. CI 103. Acetate 38. Mg 1-1.5. Ca 4 i E q / l , Glucose 0-1 g%.(SO). Far the part 4-15 months these sasc patients have been placed on a dialysis schedule of 2-2 112 hrr every other day with the save

filters and recirculating dialyratc (40 1). containing Na 135.138. 6 0-4. Bicarbonate 35, Acetate 10. C 1 9 7 mEq/l, Glucose 0 (USRO).

The f y u c n c y difference o f clinical accidents between 310 SO and 465 USRD *as :

VONI,lING (13.22 SD; 1.12 USRD) - COLLAPSE (16.92 SD; 8.62 USRD') - CRAHPS (12.72 SO; 9.92 USRD) - HEAOACHE (17.82 SO; 0.62 USRO) - ARRHYIMHIA (4.32 SO; 0.22 USRO).

The improved tolerance in spite of a double ultrafiltration (USRO 15.6 d l m i n - SO 8.3 ml/min) have most likely been caused by various factors: reduced ormolarity (-302), minimal removal of catecholaminer (-682) and. substitution o f acetate with bicarbonate in the dialysate.

SHORT. LDY VOLUME. RECIRCULATING EICAREONAIE OIALYSIS - CLINICAL TOLERANCE AND EFFICIENCY EVALUATION Title:

Author(s) Salvadro A . Scgagni 5 . Villa G. Piazza V . Galli F. Eovio G Petrella E. Eigi L. *

Address: Fondaz. Clinica del Lavoro. Nephra t Dialysis Orpt. Pavia * Ec!lce Laboratories. Mirandola. Modrna - ITALY

Short dialysis with recirculating lor volume. bicarbonat~-contrining dialyrate remarkably increases the clinical tolerance to the treatment. Still. owing to the reduced efficiency. uremic ryuptomr could reappear. Our purpose is to evaluate if a partial regeneration o f the dialyratc with a charcoal and rluminosiliratr cartridge could improve the efficiency of dialysis besides maintaining a goad tolerance. Four anuric patients were chosen ( 1 M . 3 F) for their high dialytic intolerance. mean age

51.2 y r r (range 49-55 ) . mean "right 62.6 K g (range 51-70). on RDT for 16.5 months (range 49-96). lhey were sritchcd from standard single pass dialysis o f 4 hrl3rIrcekly using I rq.. cuprophanr dialyzcrs (SO) to 3 hrsl3x/rcckly recirculating ( 4 0 L ) bicarbonate dialysis without cartridge fo r 3 m m t h r (RED) and finally with the latter procedure but with cartridge for 3 ~ O P L months (RECD). Percentages o f dialytic intolerance symptoms mere JS f o l l w s : OVERALL SYMPTOHS 722 (SO) I82 ( R B O )

I52 (RECO). HYPOTENSION 172 (SO) 52 ( R E O ) 32 (RECO). COLLAPSE 292 (SO) O ( R B 0 ) If(REC0). VOHlllNG 42 (SO) O(R8O) IZ(RBC0). CRAMPS 62 (SO) 122

(RED) 52(RECO). HEAOACHE 42 (SO) IX(RED) IZ(REC0). OTHERS IOf(S0) 0 ( R B O ) IZ(RECD). The table shorr some prcdialyris v a l u e r o f these patienis:

(SO) (RED) (RECO) UREA(*) O.3lt0.07 0.3720.06 0.33'0.08 CREATINIWE (*) 892z194 106912 I2 9722221 POTASSIUM(*) 5.4f0.7 5.6:0.7 5.2'0.6 PHOSPHATES(*) 2 . 2 2 9 . 8 310.5 2.29?0.4 HCOj(*) 16.4'2.3 19.52.4 24.592.3

('1 ..ol/l (I) r.0111 _________________-._____________________---------------------.----------

In conclusion. RBCO provides both a goad efficiency and a goad tolerance to the trratarnt.

OPTIMUM TOLERLNCE T O ULTRAFILTRITION Y I T H LOU VOLUME Tit'e: RECIRCULATIWG BICARBOWATE DIALYSIS (RED).

Author(s): Salvadeo A.Segagni S. Villa 6. Piazza V. Galli F . Eivio 6.*

Address:

Petrella E. Bigi L. * Fondarione Clinica del Lavoro,Ncphro E Dialysis Dept. Pavia - Erllco Laboratories. UIrandola. llodena ITALY

Ultrafiltration r a t e (UF) is one o f the most critical factors o f mrbidity during dialysis. Previous works have dcaonstratcd that RBO reduces vascular stress and improver the tolerance. our purpose was

to evaluate RED'S ability to increase v a r c u l a r stability despite high UF.

Four patients (I M. 3 F ) showing remarkable dialytic intolerance (age 49-55 yrrlrcight 51-70 Kg) on RE0 f o r over 49 months (khrl 3x/reckly) using I aq.m cuprophanc didyzrr in single pass acetate dialysis (SO), were switched to 3 hrl3*/ucrkly bicarbonate dialysis "ith 40 L of dialysatr recirculating on cartridges containing charcoal and aluainorilicatc. Na in dialysatc MIS 138 mEq.1 both in SO and RBD. The period of obrarvatisn was 3 months for SO and 3 months for RED. UF #as 1.9' l . E .I/. (SO) and 1422.4 .1/. (REO). Percentages of intolerance symptois " e r e as fallorr: OVERALL 122 (SO) I52 (RED). HYPOTENSION 172 (SD) 32 (RED). COLLAPSE 292 (SO) 12 (RED), VOMIT ING 42 (SD) I t (RED). CRAHPS E2 (SO) 5X (RED), HEADACHE 42 (SO) I2 (RED). OTHERS L O X (SD) 12 (RBD). Mirimui dizrtdir bleed prtsrvra variations during dialysis

22.1 : 5 nmHg (SO) and 15.2 ? 3.7 (RED). Harime. pulse rate uariations were 20 * 6.1 (SD) and E L 2.4 (RED).

I c can conclude that RED not o n l y increaser the vascular

stability but also considerably reducer the morbidity rith high UF even in patients already suffering o f marked dialytic intolerance.

Title: EEG changes i n bicarbonate d i a l y s i s

Author1sl:A. Giannrmde , P. C a n t il, P. A 1 l a r i a , A.Limido: * c

- . I - D.Porazzi**, P. Rovet ta**. i t

Address:Ve hro lo and Dialygis Unit-Division of Ne ~n?omr**%iistn A r + 1 7 . i n Hncn?tal-Ttalv

P a t h o l o j i c a i - EEG-changes a re frequent i n the coursc of d i a l y s i s thcrapy and appear a s a X i l e p a r a l l e l t o c l i n i c a l observat ions such as headache,nausea and vomiting. The i n c i d w c e and p a t t e r n of t hese symthoms ve re r epor t ed t o be lover i n bicarbonate dialysis(BD)than a c e t a t e dialysis(AD). D u r i h o the conplete d i a l y s i s treatment and a t regular i n t e r - v a l s thereafter(4--24 h r s ) ,ve have the re fo re cont i - nuously recorded EEG,usinT automatic frequency ev_a lua t ion i n 10 uraemic p a t i e n t s i'n RDT. Each pat ient was t r e a t e d a l t e r n a t i v e l y with AD(Na 138, Acetate 38 mEq/l)and with BD(Na 138, Bicarbonate 3 0 mEq/ l ) . I n t h e same time symthoms and blood parameters,ob- t a ined throuoh emogasanalysis were r cpea ted ly evaluated. An inc rease i n pathological EEG changes va? constant ly observed dluring both t r e a t n e n t even i f t he c l i n i c a l synthoms were lacking. Durina AD t h e p a t t e r n vas ca rac the r i zed by lowering o f d rythm ant an i nc rease i n t h e occurrence of d i s rhy t lmia (0.5- 4 Hz and 4-7 Hz waves frequencies)vi th naxinal ap- pearance a t 150-180 min of treatment. I n t h e casc of SD,thc EEG chances were ca rac the r i zed by a redu- c t i o n i n p o t e n t i a l of base frequencies vhieh sometimes a p e a r s abol ished and v i t h the aprearance of slow rythms l i m i t n t e d t o 4-7 Hz. The c o r r e l a t i o n s of symtho~s and blood changes t o EEG a n a l y s i s d-- monstratcd t h a t ED p a t t e r n s observed were i n nccor- dance with t h e b e t t e r t o l e rance to treatment. A more s t a b l e pC02 during th- proc-rhirc, a l ove r i nc i - dence of hypotension and a b e t t e r ca rpe r sa t ion of ac idos i s does not seem s u f f i c i e n t t o aSolish CE!S disturbance during d i a l v s i s .

204

May 1981 Communications 0 .

~ 1 ~ 1 ~ : Incroased vrntrictrlar perEormmce in iiraemic

AuthOr(s):A. Giangrande, P. Allaria, A . L imi do, patients after sodium ovcrload

Wit11 the p n p o s p to investicjate the myocardial fun ction of uracmic, a c a r d i o m e c h . ~ n i c & l - ~ v r l u a t i o n o! taised by vawrPme!it of syst-lic time intorvalr (STI) vas ,~?fi~rta!.en in 10 patirnts on !<W 2TteT an acute ov-rload(4 1?1,hg/20 min)of 4 diffrrr!?t 02 molarity and scdiiim content solutions ( 5 % dpxtrosi -3.6;! Tham-5;: IbaHCO,-3.7% NaCI) . Thn ?ypertonic infusions ?rodvced a si"tlific2nt improvrme!i+f ve-2 tricular ~ ~ r f o r m a i c c n,it!iout any concurrrnt mean arterial pressure cI~~?nqcs. The corrclation het- ween plasma v,:liies (!Iaf'b,p, "1, HCO;) a5.d STI was positive fo r Na' changes (pCO.001) for all STI, ahile the correlation with osmolarity was veak (pCO.05) a!id linited to PCP/LVB1' and PEP1 and niuA tiple retgresrion analysis has confirm that thc main role in improvin? ventricular perfcrmancc ha- longs to sodium. /3 -adrcn-r:lic b!ocL ohtained, be fore the infusion OF KaC1, vit.: i.v. oxprenolol (0.1 m!,/Kg/lO min) does not abolished the ve!?tri- ciilar impoovcment. These results pointed out that Na overload has capable to induce 4'1 improvement of ventric.ilar performance in r~raemic hearts. T h ? s increased inotropic effect does not appear mediated byp-adrencrTic mech-nisms.

0

Title: Ultrashort simultaneous Hemofiltation/

Author(s) :

Address :

Simultaneous Hemofiltration/Hemodialysis (SHFHD) which combines the advantages of both hemodialysis (high efficiency) and hemofiltration (improved tolorance of water removal) has been practi- ced in our unit 'since 1 9 7 6 . Despite the reduction of treatment time to 3 x 2 , 5 - 3 h/week with this method no adverse effects could be detected in 27 patients so far. Experiments were undertaken to further diminish the weekly treatment requirement. Commercially available dialysers suitable for SHFHD were arran- ged in parallel or in series in a single pass dialysat flow system provided by an artificial kidney containing both a controlled ultrafiltration system and a device for automatic fluid replacement. Working conditions were as follows: QB:300-400 ml/min, QD: 500 ml/min, TMP:500 nun Hg.

Based on the measured elimination rates (urea, creatinine, middle molecules, inuline), on the tolerated ultrafiltration rate (12L/90 min), on the measured hemodynamic parameters and on the predialytic laboratory findings a new modifica- tionof SHEHD, termed USHFHD, will be presented permitting treatment times of 3x90 min/week. Today 4 chronic uremic patients are regulary treated according to this schedule without side effects. More deta:.ls will be presented during the congress.

HemoZialysis (USHFHD). ~.w.Leber, v.Wizemann,P.Rawer,F.Techert

Medizinische Klinik, 6 3 0 0 Giessen , FRG

Tit,e Intraluminal perfusion of the large

Author@): Wizemann, V.; Volz, H. ; Zahn, B.

Address: Medizinische Klinik, 6 3 Giessen, FRG

intestine - therapy in renal failure?

Using a proximal colostomy the complete colon was

perfused in 13 pigs to evaluate the elimination capacity for uremic waste products. Urea, creati-

nine and B,* were infused i.v. until an equili- brium was reached. Colonic elimination was dependent on the perfusate flow rate (1-3 l / h ) i

maximally 4 mg creatinine/h and 5 0 mg urea/h could be removed. There was a large loss of pro-

tein ( 6 0 - 2 0 0 mg/h), which was also dependent on the flow rate. Addition of theophylline, PGE1, PGE2 to the perfusate had no influence on elimination rates whereas Na-deoxycholate increased elimination 5-fold. Histologically the mucosa of the colon showed an inflammation. Two animals were nephrectomized and died during 80 hours although a colonic perfusion was performed for 2 5 hours. It is concluded that intraluminal perfusion of

the colon as therapy in renal failure is ineffec- tive and dangerous.

Title:

Author(s): Pigkin, E., Fakmakli, F., Mutlu, M., Pigkin, K., Address: Chemical Engineering Dept., Hacettepe University,

COMPARISON OF MASS TRANSFER PROPERTIES OF SOME OF THE MEMBRANE SYSTEMS SUITABLE FOR HEMOPERFUSION

Giiven, 0. and Ozdural. A.R.

Beytepe, Ankara, Turkey

In hemoperfusion columns, the removal rates of toxins are mostly controlled by the mass cransfer resistance of the coating material. With this in mind, to find the best coating material for hemoperfusion, the experiments were performed using the charcoal granules coated with nylon; silicone; polyethylene glycol; cellulose nitrate; cellulose acetate and its derivatives. In all membrane systems, the membrane thickness was kept constant (0.5% by weight). Either two liters of creatinine aqueous solution or two liters of vitamin B-12 aqueous solution was recirculated through the hemoperfusion columns for testing the membrane systems. All experiments were performed exactly at the same working conditions. The clearance data were obtained for each system. With the batch experiments, the Freundlich and Langmuir adsorption isotherms were also determined. The highest removal rates were obtained with cellulose nitrate, polyethylene glycol and silicone membrane systems. It was also observed that with cellulose acetate and nylon membrane systems the mass transfer resistance can be reduced significantly by using KOH, formamid and polyethylene glycol and thus higher removal rates can be achieved.

205

Artificial Organs Vol. 5, No, 2

Title: AUGMENTATION OFMASSTRANSFER IN HEMOPERFUSION COLUMNS WITH PULSATILE FLOW

AuthorW:

Address:

P,@kin. E., Lizo~lu. E..Pi$kiin. K.. and Lhdural. A.R.

Hneetteps Untverrlly. Chemical En& Dept., Bcyt~pe. Ankan . Turkey

Hydmdynunic conditions are important in design of sotption devices. In the p w n t dudy. puhtlle &w was u d in a recirculation system in order to achieve more eflldcnt omoval of toxins. including middle molecules, in hemopertudon eohtmos. For expeimmtatlon. two Ute= of aqueous solution of the teat molecule WM rrelrmlated through iixed-bed charcoal calumm at pulsatile and pulseless no=. Ihe tu t mokcule6 In the molecular welght nnge from 113 (crutinlne) to 1355 (vttunln 8-12) were used. The experiments were conducted using 6eUulore nltrste mated chueod (0.5% by welght). Same experiments were repeated udng unmated rbUc0.l. It w u found that pulutllc flow is more favounble than steady flow with ragard to d m U e of boundug layer thlcknen sunuunding chlrmal particla, which wiil cause a sltnificdnt enhmeemmt of the overdl m s s kmfer coef5clent in hemo- p M o n columnr. When coated charcoal granules were used, as the solute moleculu weight LncreUed, f lu ld-phe redrtnnces b e m e relalively lers important and the huuport rate beams dominated morUy by the coating material pmpntiin. However, it is Interestingly ohviou. that, at the same flow nte, the performance of the column was h e m u d at least 20% worLlng at pulsatile regime for the molecular welght rang+ whlch wasused in this Ftudy.

a m EFFECTS OF THE CHARCOAL HEMOPERFUSION( HP) ON

Title: ACID-9ASE 7ALANCE AND 7LOOD GAS I N U R E M I A . Mas t rangelo F. ,Alfonso L. . r l i z z e l l i S . .Co:

Aulhor(s):lianb C . , D e Alasi V.,Aprile M.. Wongiorno Department of Nephrology and Dialysis .Gen.

Address:Reg.Hosp.Lecce ( I t a l y )

E.

The p o s s i b i l i t y t o u t i l i z e charcoa l HP i n uremic p a t i e n t s a s a l t e r n a t i v e or complement t o hemodialy sis l e a d s us t o s t u d y t h e d i r e c t e f f e c t s of HP on acid-base ba lance .10 p a t i e n t s vere s tudied :5 kept unchanged weekly d i a l y t i c t i m e and added HP one t i me a veek(Pro toco1 A) ,5 reduced veekly d i a l y t i c tx me of 30% and added HP one t i m e a veek(Pro toco1 A).. Resii1ts:HP d o e s n o t i n f l u e n c e t h e acid-base b a l a n c e i n a d i r e c t manner.In fact,pH,HCO and base ex cess remain unchanged(Prot .A)in t h e s o u r s e of tr: a tment . i f t h e d i a l y t i c time remains unchanged.Ne ver the less .HP i s n o t s u f f i c i e n t t o a v o i d t h e inme_ a s e of a c i d o s i s , i f t h e weekly d i a l y t i c t i m e i s re duced(Prot.B).Data of k i n e t i c s shov that .owing t o blood t r a n s i t i n t o t h e charcoa1 ,no s i g n i f i c a n t cha nges of pH.b icarbonate and b a s e excess vere bound. This phenomenon p l a c e s a v e r y s e r i o u s problem,par t i c u l a r l y i n p a t i e n t s vhose d i a l y t i c t ime i s r e d n ced ,because of t h e r i s k t o i n c r e a s e ac idos is .Us ing b i c a r b o n a t e i n d i a l y s a t e a s h u f f e r , t h e j n t r a d i a l y t ic g a i n of b a s e s c o u l d be improved and t h e a c i d 2 sis c0r rec ted .A second phenomenon examined i s t h e e f f e c t of t h e c h a r c o a l on blood gas.HP changes t h e gas p r e s s i o n . p a r t i c u l a r l y p02.vhich dwindles during t h e t r a n s i t t h r o u g h t h e c a r t r i g e . I t is p r o b a b l e t h a t t h e d r o p of t h e O2 i s owing t o a d s o r p t i o n p h e nomenon from t h e c h a r c o a l . 1 n f a c t , i t i s showed a ) a f a l l of the c l e a r a n c e s of pop d u r i n g t h e t r e a t ment i n v i v o , b ) a f a l l of t h e O2 Clearances and re duction Of the ' c a d s o r p t i o n in vitro.

CHARCOAL HSMOPF~FIISIOW( HP) I N THE TREATMENT OF Title:llR$MT.A.

M?+tran. e l 0 F . . R i z z e l l i S . ,Alfonso L . , C o r Author(s)lianb C:.?uonqiorno l?.,Da A l a S i V.,AprilP Address: ~ p p a r t m e n t of NPDhrology and ~ i a l y s i s . G e n .

Zrppr iences r e l e v a n t t n r n e r l i b i c a l 1 1 9 ~ of charcn a 1 !!P i n uremic p a t i e n t s a r e y e t v e r y po0r.A c h a r coal covered by hydrossyethvlmetacrilate membrane (Model Hemoadsorba 150)has been u t i l i z e d i n 2 p r o t o c o l + . I n t h e P i r s t ( A ) , S p a t i e n t s have r e p l a c e d an hemodia ly t ic seance v i t h an HP+HD seance keeping u_" changed t h e d i a l y t i c schedule . In t h e second(B), 5 p z t i e n t s . i n good s t a t e O F h m l t h . h a v e r e p l a c r d an tm seance v i t h ah HP+HD s e a n c e by r e d u c t i o n of t h e w-f k l y d i a l y t i c t ime of 30%.Period of s tudy: 5 months. Resu1ts:in Pro tocol A,aOdi t ion O F HP c a u s e s a clin-i z a l improvement i n 33% of pat ients .From biochemical v ievpoin t ,was te molecules don ' t show s i g n i f i c a n t :hangcs;anemlc s t a t e i s n o t favourably nfFected:FTti 7 and T shov a 4ecreaBe.The s e r u m l i p i d s don ' t d o w s i g t i f i c a n t changes.In b o t o c o l ~ , ? C J % of p a t i e n t s shovs a f u r t h e r improvement of t h e c l j n i c a l ; t a t e d u r i n g t h e F i r s t 3 months of t r e a t m e n t ; a , F t e ~ vards ,60% of p a t i e n t s shovs a s h i f t h y a p p e a r a n c e o f ina8equat.e d i a l y s i s s m p t o m s ( a + t h e n i a , sevual imp2 tence,voni i t ing i n t h e day b e f o r e t h e d i a l y t i c sen!! ze .e tc . ) . N o changes in serum 1 i p i d s . t r y ~ l y c e r i d e s . > h o l e s t e r o l and a l k a l i n e phosphatase a r e shoves. 9Jt; z r e a t i n i n e and anemia i n c r e a s e p r o q r e s s i v e l v . a c i d o ;is i n c r e a s e s g r a d u a l l y i n p a t i e n t s i n a c e t a t e di;r 1ysis.Conclusions:HP s h o w a f a v o u r a b l e e f f e c t on ;ome c l i n i c a l t roubl p 5 . A weekly d i a l y t i c seance hv SP(charcoa1 gr.15O)does n o t compensate t h e +hare > f 30% o f t h e u s u a l d i a l y t i c proqram.

Reg.Hosp. Lecce ( T t a l y )

Title: ACUTE MASSIVE D I G O X I N I N T O X I C A T I O N TREATED BY HE- MOPFRFUSION (HP) WITH AMBERLITE XAD-4 RESIN.

Author(s) Mulec, H., Andersson, J.E., Enkvis t , C. and Redfors, A.

Address; Department of Medicine and c l i n i c a l c i e n i s I r _ s

P - n i r = l l = - r a t t a t . %Ah7 01 VANERSBORG. Sweden Digoxin i s e f f e c t i v e l y e l imina ted from t h e blood by HP, bu t t o what ex ten t t o x i c o l o g i c a l l y r e l e v a n t amounts can be removed has been ques t ioned . We r e p o r t a case of mas- s i v e i n t e n t i o n a l digoxin i n t o x i c a t i o n wi th fa ta l outcome t r e a t e d by e a r l y HP. Case r epor t : A 61 y r o ld man was admi t ted l* h a f t e r in- g e s t i o n of about 25 mg digoxin. 5 h a f t e r t h e drug had been inges t ed , HP w a s begun a t a blood f l o w r a t e o f 300 ml/min, PCV 40 %. An AV block 111 developed and a pacema- k e r w a s i n se r t ed . The f i r s t v e n t r i c u l a r f i b r i l l a t i o n (VF: was noted 8 h a f t e r t h e i n g e s t i o n o f t h e drug. 4 h l a t e r t he p a t i e n t had r epea ted VF and d i ed i n ca rd iac a r r e s t 12+ h a f t e r admission. Arrythmias were t r e a t e d us ing a pacemaker, l i d o c a i n p r a c t o l o l and DC shock, and hyper- kalemia (7.8 mmol/lj by hemodialysis. Resu1ts:Z h a f t e r se l f -poisoning , P-aigoxin was 55 nmol/l ( t h e r a n g e 1 - 2 nmol/l). During t h e 4 h of HP t h e ar- t e r i a l plasma l e v e l dec l ined from 41 t o 29 nmol/l. A t tht t i m e of dea th , P-digoxin was 2 5 nmol/l. The H€ plasma c l ea rance f o r digoxin w a s l j 5 ml/min. The t o t a l amount e l imina ted w a s 0.9 mg as c a l c u l a t e d from plasma c learanc t From the r e s i n 0.6 mg w a s ex t r ac t ed . The amount o f dig- ox in i n t h e u r i n e was about 0.6 mg. Digoxin l e v e l s i n thc h e a r t ranged from 1.1 mg/kg dw (left a t r ium) t o 2 . 3 mg/k( dw ( l e f t v e n t r i c l e ) compared t o normal t h e r l e v e l s of about 0.4 rng/kg dw. The d igoxin concen t r a t ion i n s k s l e t a l muscle was 0.58 mg/kg dw compared t o normal t h e r va lues of 0.02 - 0.04 mg/kg dw. Conclusion: Digoxin was removed from t h e blood by r e s i n IIP a t a plasma c l ea rance o f 135 ml/min. However, t h e to- t a l amount of t h e drug removed (0.9 mg) w a s only 4 96 o f t h e presumed inges t ed dose (25 mg). W could not su f f i - c i e n t l y reduce P-digoxin and the reby prevent o r , i n any dec i s ive way, i n f luence t h e accumulation o f digoxin i n t h e t i s s u e s where h igh ly t o x i c v a l u e s w e r e ob ta ined re- s u l t i n g i n dea th i n c a r d i a c a r ry thmia .

206

May 1981 0

Communications

Title: HEMOPEFFUSION (HP) WIT14 AMBERLITE XAD-4 RESIN FOR

Author(s): Mulec, H , Vikgren, P and Nyqv i s t , A. TREATME:NT OF INTOXICATIONS I N A COUNTY HOSPITAL.

Department of medicine and i n t e n s i v e c a r e u n i t , C e n i r a l l a s a r e t t e t Vanersborg, Sweden.

A s modern c o n s e r v a t i v e t r e a t m e n t of s e l f p o i s o n i n g i n t h e i n t e n s i v e c a r e .Anit a l l r e a d y o f f e r s a l o w m o r t a l i t y , t h e c l i - n i c a l b e n e f i t of HP h a s been ques t ioned . It h a s a l s o been cons ide red hazardous. We r e p o r t an a t t e m p t on a p a r t o f he- m o d i a l y s i s and i n t e n s i v e c a r e u n i t t o r educe t h e morb id i ty and m o r t a l i t y of s e l f po i son ing by a d d i n g HP t o conven t iona l s u p p o r t i v e maxagement. Method and m a t e r i a l : In 1980 85 i n t o x i c a t e d p a t i e n t s were admi t t ed t o t i e i n t e n s i v e c a r e u n i t , o f them 14 were i n t u b a - t ed . HP w i t h Amberlite XAD-4 was performed on seven p a t i e n t s for t h e fo l lowing r easons : C o r t i n a r i u s mushroom p o i s o n i n g (1 p a t i e n t ) , massive a c u t e d igox in ove rdose 25 mg ( 2 pa- t i e n t s ) and s e l f - i n t o x i c a t i o n w i t h h igh d o s e s o f p sycho t ro - p i c d r u g s ( a m i t r i p t y l i n e and c l o m e t h i a z o l , c lomipramine and carbamazepine, prometazine and hexapropymate w i t h lo razepam) 4 p a t i e n t s , a l l i n grade I V coma. Resu l t s : The f o u r p a t i e n t s i n g rade I V coma were e x t u b a t e d d u r i n g HP and dischar-ged from t h e i n t e n s i v e c a r e u n i t t h e day a f t e r HP. The c o n c e n t r a t i o n of c lome th iazo l w a s reduced from 8 umol t o 4 umol/l and t h e c o n c e n t r a t i o n of carbamaze- p i n e from 700 t o 265 umol/l a f t e r 4 h o u r s o f t r e a t m e n t a t b loodf low 300 ml/min. The two d igox in i n t o x i c a t e d p a t i e n t s d i e d i n c a r d i a c a r r e s t . The c o r t i n a r i u s mushroom po i soned p a t i e n t r ecove red w i t h n e a r l y normal k idney f u n c t i o n a f t e r 4 weeks o n hemodia lys i s . No s i d e e f f e c t s caused by HP were observed exce?: for t r a n s i e n t t rombocytopenia . We conclude t i a t HP i n s e v e r e i n t o x i c a t i o n s w i t h psycho t ro - p i c d r u g s r e d i c e s t h e d u r a t i o n o f coma and need f o r i n t e n - s i v e c a r e . I n a u n i t expe r i enced i n h a n d l i n g e x t r a c o r p o r e a l c i r c u l a t o r y sys t ems i t is a s a f e t r e a t m e n t .

Ti,,e:

Author(s): R.D. Hughes, S. Braude, P.J . Mellon,

Address: L ive r U n i t , K ing ' s C o l l e g e H o s p i t a l & Medical

S e r i a l Resin Haemoperfusion i n t h e Treatment of Fulminant Hepa t i c F a i l u r e

P.G. Langley, A.E.S. Gimson & Roger Williams

Schoo l , Denmark H i l l , London S.E.5.

The use of haemoperfusion t o remove p r o t e i n bound and middle molecu la r weight t o x i n s from t h e c i r c u l a t i o n o f p a t i e n t s w i t h fu lminan t h e p a t i c f a i l u r e has p r e v i o u s l y been p reven ted by t h e poor blood c o m p a t i b i l i t y o f p o t e n t i a l adso rben t s . T h i s problem has been overcome by c o a t i n g Amber l i t e XAD-7 wi th human serum albumin (Immuno L td . ) and seven p a t i e n t s w i th Grade I11 o r I V h e p a t i c coma due t o fu lminan t h e p a t i c f a i l u r e ( f i v e pa race tamol ove rdose , two v i r a l h e p a t i t i s ) have been t r e a t e d by d a i l y r e s i n haemoperfusion.

Blood c o m p a t i b i l i t y w a s e x c e l l e n t ; a f t e r 4 hours t h e mean p l a t e l e t l e v e l w a s 97.6 2 SEM 4.6% and w h i t e ce l l l e v e l 705.8 2 8.3% bo th % of i n i t i a l l e v e l (n = 18). There were no s i g n i f i c a n t changes d u r i n g haemoperfusion i n m e a n a r t e r i a l blood p r e s s u r e , Swank s c r e e n f i l t r a t i o n p r e s s u r e or i n t r a c r a n i a l p r e s s u r e i n t h o s e p a t i e n t s monitored. The l e v e l s of con juga ted and uncon juga ted b i l i r u b i n and b i l e a c i d s were measured d u r i n g t r e a t m e n t . Three p a t i e n t s r e g a i n e d consc iousness and r ecove red t o l e a v e h o s p i t a l . I n two Of t h e f o u r p a t i e n t s who d i e d t h e f i r s t haemo- p e r f u s i o n t a d t o be t e rmina ted w i t h i n one hour as a r e s u l t of t h e i r a l r e a d y poor c l i n i c a l cond i t ion .

I n summary haemoperfusion wi th t h e albumin c o a t e d r e s i n is a s a f e blood compa t ib l e p rocedure and it w i l l now be p o s s i b l e t o p roceed wi th t h e combinat ior of r e s i n and c h a r c o a l haemoperfusion f o r t h e removal of bo th water s o l u b l e and p r o t e i n bound t o x i r s .

Title: CLINICAL HAZARD, BIOCOMPATIBILITY AND REGULATION

Author(s):Dr. M.T. Cooper

Address: OTTAWA, Canada Bureau o f Medical Devices

Can t h e o v e r a l l c l i n i c a l hazard o f t h e use of medical devices be measured? What f a c t o r s must be taken i n t o account t o do t h i s ? The s i t e where the procedure takes p lace . t he person pe r fo rm ing the procedure, t he t ype o f t i s s u e invo lved , t h e area of t h e body i nvo l ved , t h e i n t e r a c t i o n between t h e f o r e i g n m a t e r i a l and the t i s s u e contacted, and the m i c r o b i o l o g i c a l s t a t e o f t h e device a r e some of the f a c t o r s wh ich would need t o be considered i n a r r i v i n g a t an index o f c l i n i c a l haza rd which c o u l d be used t o h e l p i n assessing t h e r e l a t i v e m e r i t s o f va r ious procedures.

Work has been done i n b o t h England and t h e USA on hazard assessment, m a i n l y concerning the e f f e c t a p a t i e n t ' s c o n d i t i o n has on t h e outcome o f var ious procedures. Th is needs t o be pursued and i t would form one p a r t o f t h e t o t a l hazard equa t ion .

a q u a n t i t a t i v e method o f d e s i g n a t i n g m i c r o b i o l o g i c a l sa fe ty and they use t h i s concept i n e v a l u a t i n g medical device submissions; t h i s i s ano the r f a c t o r t o be i n c o r p o r a t e d i n t o t h e C l i n i c a l Hazard Index.

Other f a c t o r s r e q u i r e more i n v e s t i g a t i o n t o develop a q u a n t i t a t i v e assessment. many f a c t o r s i s a p rob lem t o be developed by t r i a l and e r r o r s t a r t i n g w i t h a r b i t a r y values.

c o m p a t a b i l i t y t e s t i n g which shou ld be done f o r any p a r t i c u - l a r device use. The scheme developed i n Canada and submit- t e d t o t h e W.H.O. i s explained; t h i s was g i ven suppor t a t t h e F i r s t World B i o m a t e r i a l s Congress l a s t y e a r i n Baden. The two s tage approach where t h e type o f t e s t i n g r e q u i r e d i s agreed i n t e r n a t i o n a l l y b u t t h e a c t u a l t e s t s used are decided l o c a l l y i s supported. S p e c i f i c examples w i l l i l l u s t r a t e some o f t h e i n c o n s i s t e n c i e s and anomalies which can r e s u l t when r i g i d t e s t p r o t o c o l s a re l a i d down.

The Bureau o f Medical Devices in Canada has proposed

The r e l a t i v e w e i g h t i n g o f t h e

There i s a good dea l o f agreement on t h e t ype o f b i o -

Tit,e:

Authorb): M.A. Mouling

Address: Dept . , 2 4 , r u e du Genera l Dufour , 1204, Geneva.

Research i n p r o s t h e s i s or a r t i f i c i a l o r g a n s h a s a lways been o r i e n t e d towards s u b s t i t u t i o n f o r or a s s i s t i n g a l i m i t e d n m - b e r Of s p e c i f i c func t ions .The ph i losophy behind r e p l a c i n g t h e p r imary f u n c t i o n b e i n g t h a t o t h e r a d a p t i v e mechanisms w i l l i n t e r v e n e i n a compensatory manner. These d e v i c e s have been r eward ing ly i n s t r u c t i v e i n d e l i n e a t i n g t h e r e g u l a t i v e and a d a p t i v e mechanism. Our s p e c i f i c t o p i c is of i n t e r e s t i n t h e g e n e r a l f i e l d of s u b s t i t u t i o n / a r t i f i c i a l o rgans a s t h e a c u t e problems a r e s i g n a l d e t e c t i o n , m u l t i d i s c i p l i n a r y approach to a problem and o r g a n i s a t i o n o f o u r t e c h n i c a l r e s o u r c e s t o ach ieve our g o a l . C e r e b r a l p a l s y (CP) i s a neo or p e r i n a t a l a c q u i r e d d i s e a s e , c h a r a c t e r i s e d by d i f f u s e a l t e r a t i o n s o f t h e ne rvous sys t em r e s u l t i n g i n motor i npa i rmen t which s e v e r e l y i n f l u e n c e s p e r c e p t i o n , mental o r g a n i s a t i o n and c o g n i t i v e dev- e lopment i n a manner n e i t h e r p r e d i c t a b l e nor q u a n t i f i a b l e . T h e problem t h e n arises a s t o d e f i n i n g which f u n c t i o n s t h e d e v i c e shou ld f u l f i l l , c o n s t r u c t i n g a n a s s i s t d e v i c e based on t h e d e s i d e r a t a and t h e n measuring i t s e f f e c t s . Two approaches have been proposed: t h e i n p u t s u b s t i t u t e and t h e o u t p u t p r o s t h e s i s . The l a t t e r no rma l i se s behav iour (e .g . communicative d e v i c e s a c t i n g o n t h e environment) compensat ing f o r l a c k o f e x p r e s s i v e and motor c a p a c i t y and aimed towards s o c i a l i n t e g r a t i o n . The i n p u t s u b s t i t u t e r e p l a c e s : ( a ) manip- u l a t i v e c a p a c i t y , feedback and c o n t r o l , (b) communicative d i a l o g u e ( w i t h computer : LOGO) norma l i se p e r s o n a l expe r i ence and aims t o achievement o f c h i l d development. Computers a r e s u f f i c i e n t l y f l e x i b l e t o p e r m i t t h e CP c h i l d t o s t z u c t u r e h i s e x p e r i e n c e s wi th t h e computer. But one o f t h e main problems is t h e d e t e c t i o n of a s i n g l e r e p r o d u c i b l e v o l o n t a r y r e sponse from t h e c h i l d s u c h t h a t a simple i n t e r r u p t i v e command may b e r ecogn ized by t h e machine. C u r r e n t e v a l u a t i v e tests a r e inadequa te f o r CP c h i l d r e n and s u b s e q u e n t l y o f t h e machine.The P i a g e t ' s t heo ry a l lows an ap- p roach t o program development and e v a l u a t i o n of i t s b e n e f i t s .

ASSIST DEVICES FOR CEREBRAL PALSIED CHILDREN :

GUIDELINES AND PERSPECTIVES.

U n i v e r s i t y of Geneva, F.A.P.S.E.,Psycholinguistic

S w i t z e r l a n d

207


QuANTITATIUE COMPUTED HISTOPHOTOMETRY OF

CAUSED 8Y IflPLANTATION TURORS Title:STRUCTURAL AND ENZYMATIC K I D N E Y ALTERATIONS

Author(s):Schlachter,T. ,Heinert ,G. ,Jayer,~. , waupel,~. , Address: U niv .

Hutten,H.,Otte,J. Clinic F rank f u rt/M. , Oe p t . u r o 1. and

univ. Mainz,Dept.Physiol.,F.~.~.

In order to analyse quantitative changes of tu- bular membrane and lysosomal located enzymes computed histophotometry of kidney tissues was per- forrned.As a parameter,indicatiny morphologic alterations in renal tissues,alkaline phosphatase (AP),alanine-aminopeptidase (AAP) and B-glucuroni- dase (a-G1) were mea5ured.A~ an experimental design,ascites Cells of DS-Carcinosarcoma were implanted into kidneys of 74 male Sprague-Oawley rats.Rena1 organs with implanted tumors,contralate- r31 kidneys as well as cancer tissues were investigated after a time period o f 7 / 1 1 and 14 days. 1 5 kidneys served as controls.Analogous measurp- mants were registered by digital display from a, computed image analysis device technique "Micro- W i d e o m a t " 2 , Z e i s s , O b e r k o c h e n , F R G . N o r m a l kidney tissues displayed uniform high enzyme profiles as fol- l o w s : AP 312,5i38,0 U (units),n=lO;AAP E44,3265,1 U,n=lO;B-Gl 706,8+38,7,11=10.Contrary to that findings as could be expr,,ed,infiltration zones o f tumors were characterized by signifikant (Wilcoxon- test,2pC<O,DOl) decreases of enzyme concentrations a s compared to normal kidney cortex tissues (100%); RP 32,1~25,5,n=2I;AAP 191,7~134,2,n=12;C-C1 233,E - +163,4,n=13.In addition,the tumor adjacent kidney tissues were observed by decreased enzyme activity.The structural alteration was depending from time,localisation and expansion of cancer.As could b e expected, tumors exhibited signifikant decreased enzyme concentrations and there was no difference assessed in cancer tissues after different time pe- r i o d s of 7 / 1 1 and 14 days:AP 5,7~12,0,n=22;AAP 6,9+10,3 Uln=13;D-G1 258,1+23,2 u,n=IS.Quantitative computed histophotometry of enzyme concentrations i r l renal organs after tumor implantation appears

t o be a tool in monitoring kidney alterations.

Title:

Author(s1:

Address:

0 MONITORING CARDIAC OUTPUT WITH A NEW HOT- FILM ANEMOMETER PROBE, MOUNTED ON A SWAN- GANZ THERMODILUTION CATHETER. Peter Kildeberg Paulsen, Department of Thoracic and Cardiovascular Surgery, Arhus Kommunehosp, Arhus, Denmark.

Cardiac output is an important parameter in postoperative care and evaluation of critically ill patients. Many methods - including electromagnetic and Doppler catheter tip transducers - have been used to monitor C. 0. Some problems using catheter velocity probes in- clude difficult calibration, unknown velocity profile - and probe position in this profile - at the point of measurement in the vessel. Trying to avoid these problems we mounted a double conical hot-film anemometer probe at the tip of a Swan-Ganz thermodilution catheter and used the intermittent thermodilution method to "in vivo" and "in situ" calibrate the continuous velocity curve from the anemometer. MATERIAL AND METHODS: Mongrel dogs were used. After a sternotomy the thermodilution catheter with the hot- film tip was placed somewhere in the pulmonary artery. Simultaneous registrations of C. 0. (thermodilution and blood velocity (anemometer) were registered over a wide range of flows. Expecting a stable position of the tip the velocity was thought to fluctuate like cardiac output - i. e. the output voltage from the anemometer could be equalled the reading in l'/nin from the thermodilution computer. RESULTS: 59 measurements were performed in 5 dogs. A mean correlation coefficient between thermodilution and anemometer output voltage was 0 , 8 6 6 . Using the mean results from the thermodilution for calibration of the corresponding mean anemometer results gave the mean line of regression a slope of 0.796 7 0,163 (TSD) and a y-intercept of 2 4 7 14 (ml/min/kg). DISCUSSION: The main advantages of this new catheter are thus the continuous registration of a velocity which is well correlated to C. O., and a decreased total volume of injected cold saline, which is of interest in monitoring patients with heart and/or kidney insufficiency and in children. A patient safety unit for the catheter has been constructed.

0 COMPUTER-TOMOGRAPHY: A N E W APPROACH M MYOCARDIAL. STRUCTURE Title: P. P. Lunkenheimer', R . - 0 . Mflller++. Chr. Konermann+,

Author(s): Department of Thoracic and Cardiovasc. Surg.+ and the Clinic of Radiology++, Jungeblodtplatz 1 , D 4400 Mtinster; p,,jdress:

F. Kdhler+++, E. Ibershoff'

Institut of Pathology+++of thuniversity of Marburg, Robert-Koch-Str. 5 , D 3550 Marburg

The controversal idea about a transmural force component in the ventricular wall actively favour- ing an intramural antagonism bases on an oblique endo-epicardial, spiral arrangement and a dense interfibrillary netting of the myocardial body. This architecture recently has been shown in macroscopic preparations by Torrent Guasp. However, opinions are still divided about artifacts caused by heat denaturation of the myocardium which is part of the preparatory steps for macroscopic layer dissection.

cardial architecture in computer-tomography. The heart is gas-perfuaed via the coronary arteries. Myocardial texture separates along the vascular bed. The contrast: 'gas against myocardium' reveals a distinct inner fiber spiral (turning anticlock- wise from the base to the apex) and an outer thinner one (turning clockwise). Both structures characteristically change with hypertrophy, atrophy and diffuse fibrosis of the ventricular myocardial body.

of the myocardium. The resulting information helps to quantify internal work of the ventricular wall in case of fiber disarrangement.

A new method has been developed to analyse myo-

The method is prepared for pathological analysis

0

NON-INVASIVE MONITORING OF THE CARDIOPULMONARY Title: STATUS OF NEWBORNS IN THE FIRST MINUTES OF LIFE Author(s): Harald SCHACHINGER

Children's Hospital, Free University of Berlin Heubnerweg 6, D-1000 Berlin 19, Germany

Blood gas and acid base values in cord blood are often not predictive of neonatal cardiopulmonary adaptation. Oxy- gen-cardiorespirography has proved to be very useful in e- valuating cardiopulmonary adaptation of newborns. This is a non-invasive and continuous monitoring system. Recorded were beat-to-beat registered heart rate, respiratory rate, thoracic impedance, and transcutaneous Po

Such an intensive postpartal monito&ng was realized in 337 newborns. In 16 of those severe early cardiorespiratory problems were noticed in the first hours o f life, five o f whom had a congenital heart disease, while 11 babies showed respiratory distress. These diseases could not be estimated by the blood gas values of the umbilical artery. Only in 2 of the sick infants a cord blood pH below 7.15 was found, and one infant showed a low Po In all 16 infants the oxygen-cardi orespirogram revealed'; pathological pattern, at least in one of the parameters. In clinically abnormal infants the tcPo was low, and frequently a decrease of the long-term variibility of the heart rate was seen. With this monitor-screening system in 10 of the 16 sick infants a pathological pattern was recognized in the oxygen-cardiorespiro- gram before clinical symptans had appeared.

Another helpful means o f supervising cardiopulmonary adaptation during oxygen-cardiorespiratory control is the hyperoxia test. Already two minutes following hyperoxia a dif- ferentiation between healthy newborns, infants with respiratory problems or congenital heart disease with right-to-left shunt can be demonstrated. It is possible to diagnose an o- pen ductus Botalli within the first days of life by application of two tcPo electrodes, on thorax and abdmen. The ex- tent of the shun% can be related fran the Po difference between the thoracic and the abdaninal electroie.

Oxygen-cardiorespirography a1 lows continuous multipara- metric data collection and pemits the early recognition of important trends in neonatal cardiopulmonary adaptation.

Address:

208


0

Title:BLINK REFLEX I N L W M I A

Author(s) Za ra ld i A., Cappel l i G. ,Caaora t i C. ,Ta;svaf , B o r t o l o t t i P.*, Malavasi P.*,Schonhuber R.'

AddressDiYj.EiGnB d i Nefro logia-Cl in ica Neurologica p o l i c l i n i c o U n i n r s i t a r i o d i Mcdena.

S i ink re f l ex has been r e c e n t l y proposed as an index of maernic nsuropathy. The a f f e r e n t way is tri geminal, tk.6 e f f e r e n t o m is mediated by f a c i a l nerve. The e l e c t r o p h i s i o l o g i c a l t r a c e shows two d i z f e r e n t waves: R1 and 22, t h e former i 3 quick, omo- l a t e r a l and o l igos inap t i c , t h e seconc is lovr, c r o s sed and nu l t inemona l . R1 g i v e s an evalua t ion of c r m i a l nerve fuTlct-onal impaiment it has been ccns idered i n our p a t i e n t s according t o Kim& ra. 16 normal subyects were evduatec l togheter w i t 3 16 uraemics and 16 hsenobi9lysed pa t i an t s . I e m lf! tency t i c e f o r R1 in c o n t r o l s was: 11.55 f 0.63 zsec , i n uraemic pa5 ien t s was 12.56 -+ G.85 w h i l e i n haemodidyse t p a t i e n t s v.us: 13.64 2 1.14.. Eeaningfu l l d i f fe ronce s were observed between mean values of each g'roup. A l i n e a r r e l a t i o n s h i p was fow-d between s e m c r e a t i n i n e a i d R1 in uraenic pa t i en t s : y = 11.89 + 0.91 x. oul- rewlts give ev& 6ence t h a t 3:$ of uraemic p a t i e n t s in conserva t ive t r e a b e n t l i m o a c r a n i a l nerve neuropathy cor re la - ting w i t h r c n a l func t iona l inpairmont. liaemodialy- sed pcrtients show the sane de fec t h 80s of cases: hzcrnodialysis does n o t h p r o v s the a l t a r a t i c n R1. I n o w opinion blirrk reI2ex t e s t in a? easy ~ f & y to evalus te nerve func t ion in urse:nico bu t f i n t h e r s t u d i e s ~ T C G going an t o asses it ir. conparisonwith c l i x i c a l and b i o l o g i c a l behaviour.

0.

M e m t r a n e - s e p a r a t e d p lasma a s p e r f u s a t e f o r r e n a l p r e s e r v a t i o n .

T,t,e

Author(s) Kota T a k a h a s h i , H i r o s h i T o m a ,

Address 10 Xawada-cho , Shin juku-ku , Tokyo 162, J a p a n

P e r f u s a t e is known to p lay a n impor tan t r o l e in p e r -

T e t s u z o Agishi a n d Kazuo O t a . Kidney C e n t e r , T o k y o Women's' M e d i c a l C o l l e g e .

fusion p r e s e r v a t i o n of t h e k i d n e y . C r y o p r e c i p i t a t e d p lasma ( C P P ) is recommended fo r p e r f u s a t e a n d is p r e s - ently p o p u l a r in c l i n i c a l u s e . H o w e v e r , p r o b l e m 1s a low r e t r i e v a l r a r e of t h e C P P f r o m whole blood m s p i t e of t h e compl ica ted , cumbersome a n d t ime-consummg p r e p a r a t i o n p r o c e d u r e .

R e c e n t advancement m p l a s m a p h r e s i s technology h a s fac i l i t a ted s imple membrane s e p a r a t i o n of p l a s m a f r a c t i o n from whole blood. M e m b r a n e - s e p a r a t e d p lasma ( M S P ) o ined by f i l t ra t ion through a p lasma s e p a r a t o r C P l a s m a f l o 8 h a s been eva lu- a ted both in i t s b iochemica l p r o p e r t y and animal r e n a l . . . t r a n s p l a n t a t i o n .

s imi la r to tha t in C P P , c o n c e n t r a t i o n of l a r g e r molecules While c o n c e n t r a t i o n of smal l molecules In' M S P is v e r y

such a s c h o l e s t e r o l s and l ipopro te in in MSP-is markedly l e s s than tha t in C P P and f ibr inogen is not d e t e c t e d in both.

T h e p e r f u s i o n p r e s e r v a t i o n with M S P f o r 24 h o u r s is proved t o b e s ign i f icant ly s u p e r i o r to e i t h e r C P P p e r f u s i o n o r s imple hypothermic s t o r a q e by Col l ins ' method in t e r m s of function of t h e p r e s e r v e d k i d n e y s immediately a f t e r t h e revascular i ;a t ion .

In addition t o s impl ic i ty in t h e p l a s m a p r o c u r e m e n t , u s a g e of c a 2 a v e r i c blood f r o m t h e s a m e d o n o r t o t h e k idney IS c o n s i d e r e d to p r e s e n t a d v a n t a g e s not on ly m a suf f ic ien t amount of S L F ~ I Y but a l s o in e l immat ion of p o s s i b l e immuno- log ica l in te rvent ion b y h e t e r o g e n o u s blood.

Title: Development and c l i n i c a l appl ica t ion of a f i b e r op t ic

Author(s): Hiroshi Matsumoto, Naoki Furuta, Kenji Kobayashi,

Address:Deptof Thoracis Surg., Faculty of Med., Univ.of Tokyo

c a t h e t e r t i p pressure t ransducer

Tsutomu Yasuda and Kenichi Asano

7-3-1 Hongo, Bunkyo-Ku, Tokyo 113 , Japan The problems of b a s i c design concerning t h e c a t h e t e r type t ransducer f o r i n t r a c a r d i a c pressure measurement by means of f i b e r o p t i c s were technologica l ly examined. O u r c a t h e t e r which was designed ard manufactured has been c l i n i c a l l y used f o r r i g h t h e a r t c a t h e t e r i z a t i o n . With respec t t o t h e manu- fac tured c a t h e t e r : ( a ) b e t t e r p r o c e s s a b i l i t y is obtained as compared with t h e t i p t ransducer type c a t h e t e r , which incorpora tes a pressure-e lec t r ic s i g n a l t ransducer i n t o t i p , ( b ) a signal-to-noise r a t i o and s t a b i l i t y s u f f i c i e n t f o r measurement of venous pressure can be obtained with t h e manu- fac tured c a t h e t e r , ( c ) t h e frequency c h a r a c t e r i s t i c s have been proven t o be f l a t up t o much h igher than had been an- t i c i p a t e d , and t h e c a t h e t e r enabled measurements of i n t r a - card iac pressure h e a r t sound and h e a r t murmur t o b e simulta- neously taken , ( d ) comparison of waveforms and frequency a n a l y s i s of waveforms revea l t h a t t h e c a t h e t e r has d i s t i n c - t i v e l y s u p e r i o r t o o ther t i p t ransducer type c a t h e t e r . With regard t o e l e c t r i c a l s a f e t y , t h e f i b e r o p t i c c a t h e t e r has advantages over t h e conventional c a t h e t e r . If multi-chan- n e l i z i n g of t h e present c a t h e t e r w i l l be extended, much p o s s i b i l i t y f o r t h e simultaneous measurements of many hemodynamical v a r i a b l e s would e x s i s t , i n combination w i t h spec- t roscopic a n a l y t i c a l methods.

0

Title: DANGER OF C A R D I O P L E G I C SOLUTION

Author(s): A.Harjula, S .h la t t i l a , M.Harkonen, H.My1larniemi and J.Nickels

Address: Unive r s i ty of He l s ink i , Cent.Hosp., Dept. Thorac. Surg. ,Finland.

I d e a l co ld ca rd iop leg ic s o l u t i o n is n o t y e t designed. Both c r y s t a l l o i d and b l o o d ca rd iop leg ia is used. The p resen t study compares the e f f e c t s of blood ca rd iop leg ia t o c r y s t a l l o i d ca rd iop leg ia on myocardial p re se rva t ion and p a r t i c u l a r l y p re se rva t ion of coronary endothelium i n exper i - memtal s t u d y . Five sheep were s a c r i f i e d .

The i s o l a t e d h e a r t s were perfused with co ld ca rd iop leg ia , septum temperature w a s con t ro l l ed continuously and the h e a r t s were followed up t o t w o hours. Samples of main coronary a r t e r i e s and l e f t v e n t r i c u l a r musculature were taken a f t e r vary ing i n t e r v a l s . Metabolic parameters: ATP,

l a c t a t e , pyruvate were s tud ied and e l ec t ron - microscopica l s t u d i e s were performed.

and des t ruc t ed fo l lowing pe r fus ion with c rys ta l . lo id ca rd iop leg ia . Endothe l ia l c e l l s were mostly d i s -

appeared. T h e e n d o t h e l i a l l i n i n g s tayed i n t a c t a f t e r cold blood ca rd iop leg ia , ATP s t o r e s were we l l preserved and l a c t a t e concent ra t ions were low. No c o r r e l a t i o n s could be found between blood and c r y s t a l l o i d groups i n metabolic parameters.

F l o w s u r f a c e of coronary a r t e r i e s w a s deformed

Artificial Organs 0 .

The influence of dopamine treatment after

ischemically damaged prior to nephrectomy. Tit1e:transplantation on kidneys hypotensively or

Author(s):K. Kiirten , R. Grundmann Address: 5 Kaln 41, Joseph-Stelzmann-Str. 9 ,FRG

Chirurgische Universitats-Klinik K6ln

The quality of kidneyfunction after transpiantation depends on the preservation time but also on other factors like an hypotensive period in the donor or a phase of warm ischemia prior to nephrectomy. Therefore we investigated in the experiments presented here on what mechanisms hypotensive or ischemic damage is based and wether dopamine is able to improve the immediate function after transplantation of such damaged kidneys.Method:lB canine kidneys damaged by 15 min warm ischemia or lh/60 mmHg bloodpressure were stored for 24 hrs in Euro- Collins-solution and afterwards transplanted to the neck vessels of a recipient animal.Kidney function was followed for 3 hrs by PAH-clearance.Then the recipient animal got 5ug/min/ kg bodv weight dopamine by continuous infusion,while another 3 clearances were mesured.To analyse the different damaging damaging mechanisms by warm ischemia and hypotension the oxygen consumption and the enzyme release of every kidney were measured.Al1 results were compared with a control-group of only hypo- thermicly stored kidneys.Resu1ts:PAH-clearance(ml/ min/100 9 kidney weight.al1 groups n=6) dopamine- control-group lh/6ommHg 15 min warm infusion (only storage) hypotension ischemia without 27,92+13,47 15,24+7,21 4 , 3 8 ~ 3 , 6 6 with 39,39216.02 30,26+13,6 5,98+2,27

~

Conclusions:l.Dopamine is able to neutralise nearly the whole damage caused by hypotension on the kidney.2.Dopamine does not influence the effects of warm ischemia on kidney function.3.In contrast to a hypotensive damage,that is mainly caused by va- soconstriction,an ischemic damage is based on cellular destruction anda diminished metabolism.This can be proved by the values of oxygen consumption and enzyme release after transplantation.

TB3INmE AND m x H E ? a c Elmrrs of l N r P . m P ~ I v E Title: m m PRZZRWlTa USING CARDIOpLG

GIA Author(*): H.D.*hd.te, C. GrO-, C. J. PreUSse ,U.POtt,

A. W e l d Dept.surgerY B, university of IXesseldOrf, kecrenstr.5, D-4ceJ DuEssEXmFF, m

After institution of total cardi.=@mMKy bypass general hypDthermia is irduced (blood tanperam 5 min. < 27%. cardioplegic arrest is achieved ether by infusion into -- ding aorta or by selective c a m a q perfusion under pressure and volm control using special ~s and cardioplegic solution (VIDEIE-KPP doc, 3 to 4 liters for 8 to lo min.) . Deompression of the heart is wanted. This technique all- aortFc cross-clarl@ing times up to 150 min., but for safety reasons repeated cold carclioplegic @usion is camnended after 60 min. ming postirhahic reperfusion in 40 patients after aortic or m i t r a l valve replamnmt arterial and OD- blood sanples were taken after 1,3,5,7,10,15, and 20 min. to de- arteri.-mronary- ve~xls differences of potassim, a m , calcim, lactate, glucose, p ~ , po2, I~IH, d-m, CK and CK-MB. The actual -se of SUIE of these pxamters is damnstrat&. These curves describe an early washxt effect M c h is replaced by an- ' uptake effect after fm min. This behavior proves an early restart of - cell m W l i s n . Us- ally f0llcmrit-g a reperfusion tkm of lo to 15 min. mst of the w a t e r s are balanced again w h i c h m y perh3ps coincide with the myocardial ability to take over work load again.But in relation to total ischenic tirre and preoperative clinical classification as well as duration of illness reperfusion M d be prolorqd to at least 20 to 40 min. m i t y and reduced needs of additional intr-ative suppart perfusion and/or intra- and postoperative catdmlanmies in these g~oups of patients are dealing as a clinical msure of d f icient ' preservation.

Vol. 5, No. 2

T,tle: C Y T O - T O X I C I T Y EVALUATION BY TISSUE CULTURE OF SOLU-

Author(s) , S o p h i e C a r p e n t i e r . Monique Murawsky. A l a i n C a r p e n -

Address: C a r d i a q u e s . CNRS g A s s o c i a t i o n C l a u d e B e r n a r d

TIONS USE0 FOR HEART PRESERVATION AN0 STORAGE.

t ier . L a b o r a t o i r e d ' E t u d e s d e s G r e f f e s e t P r o t h P s e s

H 6 p i t a l B r o u s s a i s . 96 rue O i d o t , P a r i s , F r a n c e

Heart t r a n s p l a n t a t i o n makes i t n e c e s s a r y t o p r e s e r v e t h e v i a b i l i t y of t h e h e a r t d u r i n g t h e p e r i o d o f r e m o v a l u n t i l s u r g i c a l i m p l a n t a t i o n . The u s e of various c a r d i o p l e g i c solu- t i o n s h a s r e c e n t l y b e e n p r o p o s e d i n a d d i t i o n t o t h e c u r r e n t t e c h n i q u e of c o l d s t o r a g e t o i m p r o v e b o t h t h e d u r a t i o n a n d t h e q u a l i t y of t h e p r e s e r v a t i o n of t h e h e a r t . The e f f e c t i v e - ness of t h e s e s o l u t i o n s h a s b e e n e v a l u a t e d by e n z y m a t i c . hemodynamic and h i s t o l o g i c s t u d i e s b u t t h e c y t o - t o x i c i t y o f t h e s e s o l u t i o n s h a s n e v e r b e e n a s s e s s e d .

were i n c u b a t e d f o r 3 h o u r s a t 1 9 ' C e l s i u s w i t h t h e 1 2 most commonly u s e d c a r d i o p l e g i c s o l u t i o n s . The s o l u t i o n s were t h e n removed a n d r e p l a c e d by a c u r r e n t l y u s e d t i s s u e c u l t u r e medium : E a g l e medium + 2 0 f o e t a l calf s e r u m a t 3 7 ' C e l s i u s . A f t e r 24 h o u r s . t h e c y t o - t o x i c i t y of t h e s o l u t i o n s was e v a - l u a t e d Dy s t a i n i n g t h e cells w i t h t r y p a n b l u e . T h e number of d e a d cells v a r i e d f r o m 5 % t o 35 % : K i r c h (35 % I , F a b i a n i I [ 3 2 % I , Robb N i c h o l s o n I30 % I . B r a i m b r i d g e I1 (28 % I , B r a i m b r i d g e I 122 % l . F a b i a n i I1 [21 % I , R i n g e r + Kcl 20mE4/ml [ I 7 % I , N e w York U n i v e r s i t y [ I S %I, Benson Roe 114 %I. B r e t s c h n e i d e r 114 %I, L o l l e y [ I 1 %I. B u c k b e r g { b l o o d c a r d i o - p l e g i a l (5 % I .

I n c o n c l u s i o n . i t would a p p s m t h a t t h e v a r i o u s S o l u t i o n s u s e d f o r o r g a n p r e s e r v a t i o n a n d s t o r a g e h a v e s i g n i f i c a n t l y d i f f e r e n t t o x i c i t y l e v e l s when t e s t e d i n t i s s u e c u l t u r e . T h i s may p r o v e t o be a new i m p o r t a n t a p p l i c a t i o n o f t i s s u e c u l t u r e t e c h n i q u e f d r t e s t i n g p r e s e n t a n d f u t u r e t e c h n i q u e s of o r g a n p r e s e r v a t i o n .

Human f i b r o b l a s t s a n d e n d o t h e l i a l cel ls i n t i s s u e c u l t u r e

8 HOURS OF SUCCESSFUL HEART PRESERVATION Title: - EXPERIMENTS ON BEAGLE DOGS -

Gerlach, K . , Baer, P . , Frank, J., Pannek. H . ,

Chirurg. K l i n i k und P o l i k l i n i k i m Klinikum Char- lot tenburg, FUB, Spandauer Dam 130, 1 B e r l i n 19

AuthorW: Bucherl, E . s. Address:

One of the main problems i n hear t t ransp lanta t ion i s t h e preservat ion o f the donor organ on i t s transport t o the r e - c i p i e n t . Any morphological and biochemical a l t e r a t i o n s during the preservat ion t ime may cause a f a i l u r e o f the transplan- ta t ion . To p r o t e c t the organ from such kind o f destruct ion we appl ied a modif ied Gambro renal oreservat ion system f o r the preservat ion o f the hear t .

"Gambro Box" and t rea ted by hypothermic coronary perfusion wi th cardioplegic co lu t ion (HES). The experiments las ted a t l e a s t 8 hours. During t h i s time pH, PO2, PC02 and tempera- tu re o f the perfusate were continuously r e g i s t r a t e d . With a perfusion f low o f 30 - 50 mltmin and a pressure o f 35 mnHg the myocardial temperature was kept constant on a l e v e l o f 6OC over the time o f preservat ion. Subsequently the oroan was perfused wi th normothermic blood and s t a r t e d t o contract spontaneously w i t h i n a period o f 5 minutes. The cardio- e lectrograDhic lead showed a normal sinus rhythm.

The h i s t o l o g i c a l evidence demonstrated t h a t t h i s kind o f hear t preservat ion (even over a period o f 8 hours) i s ab le t o p r o t e c t the organ against myocardial a l t e r a t i o n s .

Af te r hear t exp lanta t ion the organ was placed i n t o the

210


MEASUPZMEm OF TISSUE PO DURING KIDNEY PERFUSION

WITH FLUDSOLR-43. Title:

Author(s): O.Ruland*, U.Spiegel*,J.Hauss*, K.Schanleben*

Address: *Dept.of Surgery,**Dept.of Med.Cytobioloyy, univ. H.Thernann**

of Miinster. Jungeblodtplatz 1, D-44 Miinster

FluosclR-43 is used to maintain the oxygen supply to the tissue. It is a perfluorotributylamine (FC-43) emulsion with average particle diameter of 0.085 micron. To furnish the emulsion with physiological osmolarity, oncotic pressure and buffer capacity,addition of hypertonic modified RINGER'S solution and human albumin is necessary. In ten isolated dog kidneys (weighti 60-90 g) the tissue PO was measured with the multiwire surface electrode(KESSLER &'

LUBBEPS).In order to estimate the oxygen supply to a tissue a kind of "representative opinion poll" is held in the organ By taking no less than 100 measurements one gets a PO -hist- ogram indicating the statistical distribution of locat PO s . During perfusion with FlucsolR-43 the oxygen values in thz tissue were shown to be significantly higher than during normal blood perfusion. The continucus registration of local tissue PO gives the opportunity to recognise changes in the microciLculatorv bed immediately. The tissue PO depends maipy on the oxygen loading of the artificial 6lood.Fluosol -43 a d on the perfusion pressure. Kidneys perfused with Fluosol -43 at 22OC maintained an unchanged high level of oxygenation even beyond a ten hour period. In light and electron microscopic examina ions of kidneys after ten hours of perfusion with Fluosol -43, no hypoxic damage was Sound. The mitochondria1 structures were incon- spicuous.No cell swelling was noted. In electrolyte and enzyme assessment from perfusate and

The qualification of FluosolR-43 as a kind of "artificial blood" for kidney perfusion in dogs will be discussed.

2

8

A '

irine no evidence of tissue damage was given.

0

~ i ~ l ~ : REPLACEMENT OF CARPAL BONES BY INJECTION IN SITV OF A NEW KIND OF MEDICAL SILICONE

Author(s): Pr A. APOIL - Ph. KOECHLIN - P. DEPLUS - HONINCER

Any disease, primitive or post-traumatic, of 0 s scaphoideum or of 0 s lunatum leads to articular incongruity. When Surgery does not permit to restore this congruence, prothetic implants must be used. Yet, the shape and the dimentions may vary from one patient to another. as a perfect anatomicd adaption isnecessary to restablish both congruence and stability, prefabricated implants are excep- tiunnally adapted, as experience proved. J . GOSSET and A. APOIL have develupped a replacement technic , by in situ moulage of the space formerly occupied by the bone. The naterial used for in situ injection is a medical silicone, shone-Puulenc - R.P. 70 533 R T V (Room temperature vulcanisedl.

Preliminary studies have &ohm no organic toxicity and a good histological tolerance.The results of in vitro medical tests : resistance to shifting, compression, could satisfy with the estimated facts by experience.

Analysis of the results confirms the functionnal qualities of these implants (COngruehce and stability). Neverthelesg they remain vulnerable to violent chocs, and their long- term resistance is still to be proved.

8 have an excellent funticnnal result, 3 good r e s u l t s 2 have a fd~lure by fracture of the prothesis.

Seventeen implants have been set since 1975.

In 13 cases of patients with a fo2lolr.u9of two years

SURGERY OF THE OESOPHAGUS: F'HE nt;Ii Title: POSTOPERATIVE TREATMENT WITH ARTIFICIAL G U T

A u t W s ) : Capello G,Rrullani A,De Vittori R.Meschini L, CaSOni M,Casciani C.

Uni v e r s i t Y of Rome P Rome I I t a 1 y .;

T h e a n a t o m i c and f u n c t i o n a l s i t u a t i o n o f t h e eso- p h a g u s make t h e e s o r h a s e a l d i s e a s e s b e i r r s v e r k o f t e n a s s o c i a t e d w i t h s e v e r e m a l n u t r i t i o n u h i c t c a r t i n f l u e n c e t h e r e s u l t s of c o n s e r v a t i v e o r s u r - s i c a l m a n a s e n l e n t . T h e r e f o r e i n t h e s e r a t i e n t s p a f - t e r a n a c c u r a t e e v a l u a t i o n of n u t r i t i o n a l s t a t u s a s u i t a b l e n u t r i t i o n a l t r e a t m e n t h a s t o b e c o n s i - d e r e d . A t t h e U n i v e r s i t y of fronger-79 r a t i e n t s w i t h n e o p l a s t i c (19) a n d nore n e o r l a s t i c (10) d i s e a s t ? s of t h e e s o r h a a u s u h i c h w e r e s c h e d u l e d f o r d e a o l i - t i v e s u r 9 e r r r h a v e b e e n t r e a t e d w i t h r r e - a n d r o s t - o p e r a t i v e T o t a l P a r e n t e r a l N u t r i t i o n ( T P N ) , A f t e r an a v e r a g e o f 14 d a y s o f * r e - o p e r a t i v e t r e a t m e n t all t h e r a t i e n t s h a v e b e e n o r e r a t e d : s u r d i c a l a o r - t a l i t r was 6.2%. The r i s k of s e r t i c , t e c h n i c a l a n d met aho'l i c con#* 1 i c a t i o n 5 i s t h e o n 1 Y d i s a d v a n t a 9 e of TPN t r e a t s e n t . W e c a n Leer i t u i t h i n r e a s o n a b l e l imi t s u s i n 9 a s t a n d a r d t e c h n i a u e a n d a s t r i c t o b s e r v a n c e o f a s e p s i s . A s r e c i a l i s e d m e d i c a l t e a s r u s t p r o v i d e a n a c c u r a t e c l i n i c a l a n d m e t a b o l i c c o n t r o l o f t h e p a t i e n t . I n our s e r i e s t h e r a t e of c o m p l i c a t i o n s o f TPN t r e a t n a e n t ( ? c a s e s of s e r s i s ) w a s 7 .6X : t h e s e c o r r l i c a t i o n s n e v e r c a u s e d mor- t a l i t y . On t h e w h o l e T o t a l P a r e r t t e r a l N u t r i t i o n s u r e l y i n f l u e n c e d s u r d i c a l r e s u l t s : n l o r t s l i t r w a s c o n t a i n e d well u n d e r 1 0 % t i n a l l t h e r a t i e n t s a p o s i t i v e n i t r o s e n b a l a n c e h a s h e e n a c h i e v e d a n d b e t t e r r e s u l t s w e r e o b t a i n e d i n t h e B - O U P u h i c h u n d e r w e n t a h i s h e r d a i l y r r o t e o - c a l o r i c i n t a k e . F u r t h e r m o r e s u r g i c a l w o u n d s d e h i s c e n c e s o r S U P P U -

r a t i o n s r w h i c h a r e conoilon i n t h e m a l n o u r i s h e d r a - t i e n t s n e v e r o c c u r r e d i n t h i s s e r i e s . T h e r e f o r e t h e f i n a l b a l a n c e o f o u r e x p e r i e n c e s u p p o r t the n u t r i t i o n a l t r e a t m e n t w h i c h allowed a s o o d T r e - o p e r a t i v e ' a e t a b o l i c ' r - r e r a ? a t i o n o f t h e r a t i e n t a n d a m u i c k P o s t - o p e r a t i v e r e c o v e r Y .

0

Title: ARTIFICIAL GUT IN THE TREATMENT OF IATROGENIC

Author@): De Vlttori R,Arullani A,Capellu G,Capuano C . Casoni M ,Casciani Cu

Address: University of Rome,Rome. Italy

LYMPHATIC EFFUSIONS

R e c o v e r y Gf i a t r o 3 e n i c 1 s n , P

a l l 1 r m P h a t i c f i s t u l a s ) is c a l r r o c e d u r e s ( l i s a t u r e o f ntericAd svr-shel ) 0 1 ~ 0 1 1

c o n s e r v a t i v e t r e a t h e n t w i t h t e l ~ t ~ c l d r b l r l i i z f c o f t h e l r n z r h r f l u i d s v e r l e t x o i , , h . i t - c r . c a l o r i c ,frcd h i i -

F e r r r o t e i c d i e t w i t h o u t I i r i t l 5 . 1F'ti I . rPaL i i ru In t 1 1 - 1

i n r a t i e n t s u i t h t h o r z c i c d u c t f i s t u 1 . 3 ~ h a 5 l~oct-r s u s 3 e s t e d Dn t h e h a s l s o f d l f f u r e n t Iriotlvdiiul-t : ' f i r s t o f a l l we n8ust r r o v i d r t h e ~ a t i e n t u i t . h i i ~ i

a d e o u a t e r r o t e o - c a l o r i c Jnd l i r i d i c ~ n t a l ' e i n o r - d e r t o meed t h e i n c r e a s e d rewJlr.rmc.riI.s o r t h e r-ri - t i e n t d u e t o t h e a b n o r t i ~ ? l l o s ~ ~ s i s e c ' u n d l v u e t tee' i a t o t a l bowel r e s t t o o h t , , i n t h e nta::iiiial r r d u c t i - o n of t h e h e r a t i c a r i d i n t e h i . 1 r i ; l l I i t n ~ b l ~ a t i c Tlow ar,d r r e s s u r e i n t h e t h o i . d c i c d u i i . . l h ~ . r n f o r r ; f ' i i - l o w i n 3 a s t a n d a r d i z e d r r o t o r o l , 4 i - a i . i f r ~ l ' , U I ! . i t

i a t r o s e n i c f i s t u l a s o f L h ? t h u r a c i r , d i i c t (set . lei- b l e ) w e r e t r e a t e d w i t h TPN.nl1 t.t,e r - a t i . e n t s I ' E C I V

v e i d i n a d d i t i o n a d a i l y a d a i l i ~ tnfu5ic4rt 500 m l . o f a 10% s o y b e a n e s u l . ; i o n . Nor, o r e r a t i v e rccot't=ri u i t h T P N t r e a t m e n t h a s h e e n o h t a i n e d i n a h <,vel'~c. se o f 1 2 d a y s , u h i c h is a tinlc. s 1 g n i f i c a t i v r l i 4 s h o r t e r t h a n t h e a v e r a s e t i m a r e ~ u r t e d bt! n t h e r a u t h o r s f o r s r o n t a n e o u s c loscJr fs o f t h c , l . r n \ r . l f ' i s t u l a , T h e r e f u r e we c-r , c o n c l u d e t h . i t i n 1.1

h a s to b e c o n s i d e r e d a s a I-,PU t h e r a r e u t i c a l ~ u , P - r o r t .

ment Of hi5lh-OeJtrUt f l S L I J l a 5 O ? thorJclc' G U C t . TNT'

21 1


Title: Artificial Lungs - Transplantation of Lungs Author(s): G.Baust, H.Aurich, M.Probst and J.Lasch Address :Klinik f Anaesthesiologie and IntenSiV- therapie,DDR-4020 Balle/Saale, Lenlnallee 16.

On the basis of extensive scientific results the present situation of the transplantation of lungs and the artificial lunga will be discussed,differences to kidney traneplantations will be stressed aad clinical perspectivee be shown. One experimental approach to an improved clinical application of artificial lungs currently under investigation in o u r laboratory is the permanent lowering of the O2 dfinity of hemoglobin by loading red blood cells In vitro with the allosteric effector inositol hexaphosphate(IHP).This method requires the entrapment of IKP into phospholipid vesicles and their subsequent fusion with erythro- cytes leading to a stable incorporation of IRP into red blood cells. If the pretreated cells a r e reintroduced into the organism the effector- mediated right-shift of the O2 binding curve of hemoglobin will lead to an increase of the per- centage of 02released in the periphery of the circulation. During our work two severe limita- t i o n s of this method which have a bearing on the clinical application became apparent: the price of the phospholipids precludes large scale application and their destructionless sterilization is not yet feasible.

Situation and Perspectives

Title: ECC AND ACTIVE SALINE VENTILATION FOR TESTING AND TRAINING RESPIRATORY MUSCLES IN DOGS.

Author(s): P. VANDERHOEFT and C. LECLERCq

Address: Departments of Thoracic Surgery, Erasme Hospital, 608 Route de Lennick 1070 Brussels,Belgium

All aquatic mammals breathe air. Could the seal ventilate a fluid 1000 times heavier ? This is tested in dogs on CPB with forced saline spontaneous ventilation ( S S ? ) . COz was used as the ventilatory drive. Measurements were made before and repeated on CPB, ventilating air (SA?) and saline ( S S ? ) . Vol Z 0 2 decreased from 19 to 13 on starting CPB through hemodilution, but 5; 0, was 76 i 12 Torr. Low ( < 30 Torr) and high ( 4 5 to 400 Torr) PaC02 were used al- ternatively. Mechanics and V/P loops were recorded.

response to increasing PCOz was depressed and curved instead of being linear. This was due to high airway resistance, to overdistension of the thorax, and, for high vo- lumes, to muscle fatigue. Lactic acid rose from I m q I 1 to 6 t 2 after 2 hours on CPB. Ventilatory dynamics ratio on SA? vs SS? with PCO? 60 ? 3 Torr, PaOp 284 t 113 were as fallows : VE 238 12 t 5 vs 8 t 3 . G pL7 t 2 vs 30 t 16 unH20, frictional resistance : 3 t 1 vs 82 * 38 HnO/l/sec, tt max 1210 2 424 vs 220 t 86 mllsec, Elastance 16 t 7 vs 16 t 10 cmH20/1 and work 8 vs 154 (arb. units). Lung parenchyma showed minor histologic lesions. Dogs that were carefully treated could survive indefinitely : 2 hours after resistance was back to 2.3 cmH20/l/sec and all other parkneters were within normal range except for a low PaO?.

Dogs could ventilate 100 1 of saline in an hour but their

? 35 vs 188 t 1 1 5 mltkglmin, cycleslmin:

Comparative studies on the level of several pa rame te r s

circulation conditions with par t icular investigations of

. Gulba, w. Heller , W. Epting, H.-E. Hoffmeister d,jress. Eberhard-Karls-Universitat Tiibingen, Abtl. fiir

Tiorax-h erz-u.G e f a k h i r u r g i e , Calwerstr .7 ,D-74 Tubingen The effects of the art if icial hear t on the human organism have not yet been fully investigated. W e report on studies concerning the clotting system. In o r d e r t o separate effects that are solely caused by the manipulation of t he hea r t , all pa rame te r s were determined in coronary blood and in venous and a r t e r i a l blood as well. The investigatiornwere done on: praekall ikrein, fibrinogen degradation products(FDP) ,f ibrin monqer s (F$) , ant i thryybin 111, fibronectin. The electrolytes C a and Zn w e r e investigated a s well. A s indicators for the rne- tabolic-system served acetoacetate, hydroxybutyrate and lactate. The blood was taken from patients with a coronary hear t d i sease exclusively. A s far as the per iphery blood is concerned, no significant changes in the levels of the electrolytes w e r e detected. YFre- ly in t%+coronary blood the re wasfin inc rease in the Mg and Zn ,yet a dec rease in the C a +level. W e attr ibute these findings to the injury of the cel& causedBy ischaemia. Re- markably the niveau of the Mg -and Zn 'le el was found below the normal s&mdard. Within 24 h the MgKlevel normali- z e s while t he Zn level drops even further - Our special attention w a s focussed on the praekallikrein. All of the patients tested showed a pronounced dec rease of this clotting-factor and kinine liberator in the venous and the arter ia l and the coronary blood as well: on an average we found 15% of the normal standard with the ex t r emes of 40% and 4. Because of the importance of the kinines on the utilisation of glucose of the ce l l s , as recently shown by Haberland et al., our fur ther interest was led to the question whether this de- c r e a s e of the praekall ikrein level with i t s consequences for t he utilisation of glucose and the clotting system c y be avoi- ded by using proteinase inhibitors such as Trasylol . Moreover we found a slight dec rease in antithrombin 111 and fibronectin. FDP w e r e not detected, yet in the majority of the sera f ibr ine monomers were found.

Title: in coronary and periphery blood under extracorporal

Authot$clotting system - including praekallikrein

, Mg

-

Postoperative l e f t ventricular function after opm heart surgery using two d i f f e ren t metl-d.5 of d o -

plegia Title:

Author(s)H.-U. Jt i t ten, H E g e l , w., W i n g , H., and

Address: De H. oalichau

t of Cardiovascul~ Surgery Mivers i ty of

Bretsehneider 's histidin barffered i n f u s i o n d c p l q i a and Kirsch's i n j ec t im-ca rd icp lq i a (maqnesimasvte-prc=-aspartateprocairae were ctmpared i n a clinical s t d y on 39 pat ients with acquired kart &ease. In 17 patients undergoing aortic valve replacement intra- operatively a M i l k micro-tip pressure transduzer catheter was placed in t3-e l e f t ven t r i c l e via the r i g h t upper puhm- nary vein. LVEOP, PLV, dp/dt mx, and vpn were recorded during 24 burs p t o p e r a t i v e l y . In 22 patients with various deseases. incluling a major sub- group of 10 patients &@ng mitral valve replacement, preoperatively a Swan-Ganz catheter was p l d in tl-e nary artery. Cardiac i n d a (CI) was detennined w i t h the Edwards t h e d l u t i o n took place before operation, 30 minutes, 3, 6 , 24, and 48

Stroke m r k index (SWI) w a s calculated f ran cardiac index am - aortic pressure. Results : After operations with myocardial pmtectian -&q to Bretschneider C I and SWI s-n& s i p i f i c a n t l y 1- de pression within 3 hours after end of bypass than a f t e r Kirsci cardioplegia. Between 6 and 24 burs postoperatively the diffe- diminished. vpn was s ign i f i can t ly higher 30 minutes a f t e r end of bypass i n the Bretschneider group. 3, 6, and 24 hours p3stopera- t ive ly there was only little difference between t o t h groups.

S m i z i n g we can m l u d e that the protection given by Bretschmider cardioplegia is superior to the protecting e f f e c t of Kirsch cardioplegia. whether this s u p r i o r i t y is only due to deeper mycardial CoDling r e su l t i ng f w the infusion mti-o.3 is oqofurkher investigation.

m e

cardiz output ccmputer. w i n g

hours after & o f bypass.

212

May 1981 0 .

Communications 0

Plasca m i d d l e n o l e c u l e s a f t e r c a r d i o - p u l r - o n a

p o l y p e p t i d e s . Title:iy b y - p a s s : a p p e a r a n c e o f f r e e a n d b o u n d

Author(s): N a r d u c c i C . , Russo L., Del hTanso F., B u r z a M. C h i d i c h i e o G.

"Huggins L a ' 6 o r a t o r y " G e n z a n o I R o a a P Address: C a r d i a c S u r i e r y D p t . S t . C a m 110 . R o n a

B i o c h e m i c a l m e d i a t o r s o f the t o x i c s t a t e i n d u c e d b y e x t r a c o r p o r e a l c i r c u l a t i o n (ECC) a r e s t i l l 02 s c u r e . We have s t u d i e d f r e e a n d b o u n d m i d d l e no1 e c u l e s o f p l a s m a u l t r a f i l t r a t e s a n d a n a f i l t r a t e s ( d i l u t e d p l a s m a 1:2) by e ; e l - c h r o n a t o e r a p h i c (UV a b s o r p t i o n ) a n d f l u o r i o e t r i c analysis . The f o l l o w i n g r e s u l t s have b e e n o b t a i n e d : - A s inc le p e a k o f p o l y p e p t i d e s a p p e a r s (M82500d)

j u s t a f t e r ECC., b u t t he re i s n o increase i n o v e r a l l n i d d l e n o l e c u l a r charce. - In in t ens ive care u n i t m u l t i p l e m i d d l e m o l e c g l a r classes are p r e s e n t i n plasma a s an e f f e c t of the d a m a g e t o the e x c r e t o r y o r g m s .

M y o c a r d i a l d e p r e s s i n g p o l y p e p t i d e s have b e e n d e n o n s t r a t e d i n s h o c k . F u r t h e r i n f e s t i e a t i o n s a r e i n p r o g r e s s t o d e t e r nine t h e s p e c i f i c t o x i c e f f e c t s on n y o c a r d i u a o f a i d d 1 e ~o l e cu l e s i d e n t i f i e d .

5000 d 1000 d

Title: Heparin Stimulation of Prostacyclin

Author(@: J. S. Fleming, A . W. Markey, B. Alexander and

Address: Depts. Surgery & Clin. P h a r m . , Royal Postgraduate Medical Schod, Hammersmith Hospltal. London W12, U.K.

Production P r i o r t o Ex'zacorporeal Cardiopulmonary Bypass.

C. Hensby.

The interest in Prostacyclin (PG12) a s an alternative to heparln anticoagulation during cardiopulmonary bypass, provoked an assessmcnt of endogenous PGI2 levels. Could heparin-induced intravascular lipolysis produce increased PG12 synthesis ?

Nine coronarv a r te ry graft patients were studied. A GO ml blood sample W A S taken a t the following five times: before and 10 minutes after heparin; a f te r 10 minutes and about 90 minutes of perfusion and 15 minutes a f te r Protamine into indomethacin-heparin iPG12 assay) and EDTA ( f ree fatty acid, total protein and platelets).

PGI was assaved by Gas Chromatography Mas Spectrometry as t f e stable 6-ox0 PGFp derivative. A l l resu l t s were corrected for haemodilution with reference t o either the total protein (PG12, FFA) or the PVC (platelets).

The PGI levels rose from 1.9 0 .45 t o 2.7 2 0.7 ng/gprot. (P <U. 005) after heparin and t o 3.1 perfusion and post protamine. The FFA rose from 7.9 2 . 8 to 13.9 2 8.7 umol/g protein (P <O. 05) after heparin but there W A S no corre'ation between PG12 and FFA (r 2 0.22). The only significant platelet change was a fall after protamine.

PGI synthesis i s increased by heparin but i s independent of intravascular lipolysis and an activation of membrane-bound phospholipas6s may be responsible.

2 0.9 ng/g prot. durlng

2

Title: The Dlalyser as a Carbon Dioxide Exchanger

Aulhor(s): D. G. Melrose, A . W. Markey and J. S. Flemlng

Address: Department of Surgery. Royal Postgraduate Medlcal School, Hammersmith Hospital. London W12. U . K .

Extracorporeal '202 removal a s a successful method of treating acute resplratory d i s t r e s s (1) has provoked interest in achieving total metabollc C02 removal a t low blood flow ra tes to reduce the complexity of cannulation procedures.

To assess the possibillty of uslng conventional open circuit acetate dlalysls 2 non-ventilated greyhounds were treated for 2& hours through 1.2 M2 Dlalade hollow fibre dlalysers. Cannulatlon from the left femoral a r te ry to the left femoral vein allowed blood flow r a t e s of 500 t o 800 mls/mlnute and the removal of up t o 140 ml/minute of COz. mainly a s bicarbonate.

In conventional dialysis the dialysate Is discarded and it i s anticipated that unacceptable loss of normal plasma components would occur when continued for days a t a t lme. We have therefore devised a closed clrcuit system and tested it in vitro. A 25 mmol/L sodium bicarbonate solution was pumped through the blood path of 2 M2 hollow f lbre dlalysers a t 400 to 600 ml/ minute. Acetate based dlalysate was recirculated a t 1 . 8 l i t res / mlnute from a reservoi r contalning 30 l i t res . The bicarbonate dlffusing Into the dlaiysate across the membrane was neutralised by a contlnuous Infusion of acetic acid and the COz so produced removed through a g a s exchange unit thus regenerating sodium acetate:

(Na+ + HC03' + H+ + CH3COO' 2 Na+ + CH3COO' + CO,? + H20)

In this system 170 ml of COZ/minute could be removed f rom the blcarbonate solutlon contlnuously. The efficlency of this closed clrcult system in animal experiments will be discussed.

1 Gattinoni e t al . Lancet 1980; 2: 292-294.

Title: CONTINUOUS OXYGEN PARTIAL PRESSURE M O N I T O R I N G

Authorb): B. Walpoth, D. Demierre, M. Turina

Address:

I N EXPERIMENTAL CARDIAC SURGERY

Surgica l C l i n i c A , University Hospi ta l , 8091 Zurich, Switzerland

Continuous a r t e r i a l PO monitoring has proven usefu l i n c r i t i c a l l y ill p a t i e n t s . This s tudy assesses PO monitoring (temperature cor rec ted PO2 Roche module) i n 15 Zongrel dogs on normo-and hypothermic cardiopulmonary bypass with var i - ab le PO, s e t t i n g s (70-350 mmHg) and v a r i a b l e hematocrits (22-37 5 ) . I n addi t ion coronary s inus blood and l e f t vent- r i c u l a r myocardial PO measurements before , during and a f t e r myocardial ischemia w&e recorded. Values were compared t o sequent ia l blood gaa a n a l y s i s using an A V L model 936. Resul t s showed: 1 . Good c o r r e l a t i o n between t h e continuous and sequent ia l a r t e r i a l blood gaz a n a l y s i s (r=0,85). 2. Acceptable c o r r e l a t i o n a t low oxygen concent ra t ions and low f low s i t u a t i o n s a s i n coronary s inus PO ( r=0 ,76) . 3. Linear relationshiphetween low (70 mmHg) and high (350mmHg) W 4.2Fast response of t h e sensor t o temperature changes (25-39OC). 5. The continuous changes o f PO myocardium during ischemia and geperfusion.

Continuous oxygen p a r t i a l pressure measurement permits optimal monitoring on cardiopulmonary bypass and a more prec iseadminis t ra t ion of oxygen. It a l s o a l laws a c lose cont ro l of t i s s u e metabolism (aerobic/anaerobic) and thereby opens new p o s s i b i l i t i e s i n experimental card iac surgery.

measurements 2

values i n s p i t e of v a r i a b l e hematocrits (22-37 %).

i n coronary s inus blood and

213

Artificial Organs

Tit,e: THE INFLUENCE OF PULSATILE FLOW ON GLUCOSE UPTAKE: AN EXPERIMENTAL STUDY.

Vol. 5, No. 2

0

CEREBRAL BLOOD FLOW I N PATIENTS DURING HYPOTHERYIC EXTRACORPOREAL CIRCULATION. THE EFFECT OF REWARMING: Tit'e'

Author(s). L e i f Henriksen, Per Skovsted & Inge H Rygg.

Address: Surgery, Rigshospi ta let . Copenhagen, Denmark. Department o f Neurology, Anesthesia and Thoracic

Hypothermic ectracorporeal c i r c u l a t i o n (ECC) has been ex- t e n s i v e l y used t o reduce oxygen demand dur ing card iac surgery operat ions. Oxygen d e l i v e r capac i ty (TaO ) i s reduced as a consequence o f hemodilution. A decrease ?n cerebral blood f l o r (CBF) secondary t o reduced metabolism. was l i k e l y t o occur ant reduce TaO f u r t h e r . We have, however, observed an increased CBF during'ECC - probably r e f l e c t i n g a s t a t e o f luxury per fu - sion. The study was perfonned t o e l u c i d a t e t o what extend CBF was increased dur ing hypothermia and af fected by the rewarming procedure.

CBF was measured i n 16 a d u l t p a t i e n t s operated f o r aquired hear t disease us ing extracorporeal c i r c u l a t i o n . The Rygg-Kyvs- gaard heart- lung machine and buble oxygenator was used f o r the extracorporeal c i r c u l a t i o n . CBF was ca lcu la ted from the c l e a r - snce curve o f i n t r a a r t e r i a l l y i n j e c t e d Xenon-133 (brachioce- p h a l i c a r t e r y ) . Measurements were obtained a f te t ; sternotomy - before ECC, dur ing steady s t a t e hypothermia (29 C) and 5 successive t imes more dur ing t h e rewarming procedure, and f i n a l l ) tw ice a f t e r the te rmina t ion o f ECC.

A h i g h l y s i g n i f i c a n t increase i n CBF from 29 t o 63 m l / l O O ~ /min was observed dur ing hypothennic ECC. The response t o rewarming was an i n i t i a l increase up t o 94 ml/lOOg/min, and the, a successive f a l l i n CBF t o values near pre-ECC values. The reason f o r the hyperperfusion dur ing hypothermia remains ob- scure. Possible explanat ions w i l l be discussed, and might be e luc ida ted by for thcoming inves t iga t ions .

Authoqs): Kuntschen F., Belenger J . , Knight C . J . , Hahn Ch. Fondation Coeur A r t i f i c i e l / L a b . Chi rurg ie Exper.

Address: 10, r o u t e des Jeunes , 1227 Geneva, Switzerland

17 p i g s (mean w t 87 kgs) underwent normothermic card io- pulmonary by-pass (CPBP) i n p u l s a t i l e (P) and continuous (C) modes of pumping with a S tocker t pump. i n f u s i o n of i n s u l i n ( 5 m U/kg/min), glucose infus ion was c o n t r o l l e d by a n A r t i f i c i a l Beta C e l l (Bios ta tor ) t o g ive a glycemia clamp.

With a cons tan t

Ten animals underwent a regime P-C-P f o r per iods of 40 minutes each mode, glucose uptake being measured dur ing t h e l a s t 20 mins of each mode.

Seven animals rece ived a regime C-P and t h r e e animals a regime of C-P-C.

I n a l l modes of pumping, CPBP was maintained with a cons- t a n t mean flow of 55 cc/kg/min.

Glucose uptake was measured pre-CPBP and during each pumping mode.

Results:

a. Glucose uptake f e l l below pre-CPBP l e v e l s during continuous f l o w . ( N = 7 . P 0,005)

b. P u l s a t i l e f l o w engendered t h e same glucose uptake a s i n pre-CPBP and always h igher than t h a t i n continuous flow.

c . I n t h e series P-C-P, t h e glucose uptake i n t h e second p u l s a t i l e per iod was h igher than t h a t i n f i r s t , i n d i c a t - i n g a compensation f o r t h e lack of uptake during t h e continuous phase. (N = 9, P < 0,005).

d. By performing t h e s e sequences o f pumping i n t h e same animal, t h e confidence l i m i t s upon t h e s t a t i s t i c a l comparisons a r e h ighly s i g n i f i c a n t .

CEREBRAL BLOOD FLOW BEFORE, DURING AND FOLLOWING CARDIAC

L e i f Henriksen, E r i k Hjelms, Thimm Lindeburgh & T i t l e ~ ~ ~ ~ ~ ~ ~ USING EXTRACORPOREAL CIRCULATION.

Author@) Inae H Rvaa. Deiartmeni'of Neurology, Thoracic Surgery and Anae-

Address: sthesia, Rigshospi t a l e t , Copenhagen, Denmark.

Cerebral dysfunction and mental impairment a r e wellknown com- p l i c a t i o n s following open-heart surgery. Severa l f a c t o r s such a s reduced blood pressure , hemodilution, hypothermia, non- p u l s a t i n g f l o w , and changes i n blood gas tens ions , could i n - f luence c e r e b r a l blood flow and au toregula tory mechanisms dur ing the ex t racorporea l c i r c u l a t i o n (BBC). The purpose of t h i s study was t o e l u c i d a t e t o what e x t e n t the named multi- p lex of f a c t o r s a f f e c t e d CBF.

Cerebra l blood flow w a s measured i n 15 a d u l t p a t i e n t s undergoing surgery w i t h t h e use of ex t racorporea l c i r c u l a t i o n . CBF was c a l c u l a t e d from Xenon-133 i n t r a a r t e r i a l l y i n j e c t e d i n t o the a o r t i c root. Baseline measurements w e r e ob ta ined a f t e r the sternotomy before ECC, dur ing t h e f i r s t minutes of ECC, during s teady s t a t e hypothermic ECC, dur ing s t a t e nornw- thermic ECC, and t-uice following t h e te rmina t ion of ECC.

A f t e r sternotomy CBF was found t o be 26 ml/lOOg/min. During the f i r s t minutes of ECC, CBF f e l l i n t h e major i ty . During s teady s t a t e hypothermia, CBF was s u r p r i s i n g l y increased t o 54 m1/100g/min. Following rewarming and s t i l l on ECC, CBF f e l l to 37 m1/100g/min. 10 and 20 minutes a f t e r t h e termin- a t i o n of ECC, CBF f e l l t o 24 and 34 m1/100g/min r e s p e c t i v e l y . No r e l a t i o n s h i p between mean a r t e r i a l blood pressure (range 41) t o 100 mm Hgl and CBF was found. A s i g n i f i c a n t r e l a t i o n - s h i p was found between CBF and p a r t i a l p r e s s u r e of carbondi- ox ide i n a r t e r i a l blood.

The main f i n d i n g of our study was t h e observa t ion of a marked CBF i n c r e a s e dur ing the hypotherrnic ex t racorporea l c i r c u l a t i o n . During hypothermia b r a i n metabolism is reduced, so t h e high CBF must r e f l e c t an uncoupling o f flow and metabolism - a s t a t e of luxury per fus ion .

0

EFFECT OF BRETSCHNEIDER'S SOLUTION ON CEREBRAL BLOOD T i t ' e : ~ ~ ~ ~ IN THE RAT

L e i f Henriksen & David I Barry Author@)

Address: Department o f Neurology, R iqshosp i ta le t . Copenhagen

Bretschneider 's s o l u t i o n (a calc ium f ree , low sodium car - d iop leg ic agent conta in ing 3g/1 procain) i s comnondly used by European surgeons t o induce d i a s t o l i c cardiac a r r e s t dur ing open h e a r t surgery. Dur ing t h e card iop leg ic procedure, some o f the s o l u t i o n i s released i n t o the systemic c i r c u l a t i o n and i n t h e normal c l i n i c a l s i t u a t i o n , t h i s would be equivalent t o a 20-40 mg dose o f procain/kg body w t . The e f f e c t t h a t th i : might have on cerebra l b lood f l o w was inves t iga ted i n anaesthf t i s e d r a t s .

Fo l low ing measurement o f r e s t i n g CBF by i n t r a a r t e r i a l 133 Xenon i n j e c t i o n technique, Bretschneider 's s o l u t i o n was admi- n i s t e r e d a t a dose designed t o mimic the c l i n i c a l s i t u a t i o n (a 40 minutes in fus ion ; 0.33 ml/kg/min, fo l lowed by a bolus, 5 ml/kg, equ iva len t t o 55 mg/kg procain). CBF f e l l from the r e s t i n g f l o w of 1OCt9 m1/100g/min ( x + SEM; n.6) t o 68 t8 and 54+10 m1/100g/mTn a f t e r 15 and 35-minutes, respec t ive ly . The boTus caused no f u r t h e r decrease, the maximal e f f e c t having already been reached, and CBF was 50t5 rn1/100g/min a t 2 min a f t e r bolus i n j e c t i o n . I n f a c t , CBF sTowly returned t o - wards basel ine, being 78+4 and 93+8 ml/ loog/min a t 23 and 43 min r e s p e c t i v e l y . There was no s i g n i f i c a n t e f f e c t on e i t h e r mean a r t e r i a l b lood pressure or a r t e r i a l PC02..

which could cause t h e marked reduc t ion i n CBF. As w i t h o ther l o c a l anes the t ics , no tab ly l idoca ine . the reduc t ion i n CBF i s secondary to depression o f cerebral metabolism. A s i m i l a r e f f e c t on CBF cou ld be expected and has i n f a c t been found i n man d u r i n g open hear t surgery (Henriksen e t a1.1981, un- publ ished observa t ion) . The e f f e c t i s no t necessar i l y harm- f u l , and the depression o f metabolism may be b e n e f i c i a l when CBF i s uneven or when cerebral energy demands are l i k e l y t o exceed energy supply.

Denmark.

Procain i s the on ly component o f Bretschneider 's s o l u t i o n

214

May 1981

0

Communications

0

Title:

Author(s): E. Sowton, H. E l m q v i s t , C. Hard a f S e g e r s t a d

Address:

INTERACT1 VE PACENAKERRS FOR TACHYCARDIA

Guy's H o s p i t a l . London, Un i t ed Kingdom

Ten p a t i e n t s h a v e been t r e a t e d w i t h a n implan ted WT s t i m u l a t o r which c a n i n t e r a c t w i th a n e x t e r n a l c o n t r o l box. s t i m u l a t i o n from t h e implan ted u n i t t o t h e e x t e r n a l box and a l s o i n t h e r e v e r s e d i r e c t i o n . A m i c r o p r o c e s s o r i n t h e c o n t r o l box c a u s e s t h e i m p l a n t e d g e n e r a t o r t o p rovoke e c t o p i c b e a t s with a c c u r a t e t i m i n g from t h e p r e c e e d i n g R wave. The e l e c t r o p h y s i o l o g i c a l r e s p o n s e is t h e n a n a l y s e d and t h e t i m i n g a d j u s t e d so t h a t subsequen t b e a t s t e r m i n a t e r e - e n t r y t a c h y c a r d i a s .

s e v e r a l thousand e p i s o d e s o f t a c h y c a r d i a have been t e rmin - a t e d o v e r t h e t h r e e y e a r s t h e a p p a r a t u s h a s been i n c l i n i c a l use. Most a t t a c k s are t e r m i n a t e d w i t h i n a few seconds . The system i s f u l l y c o m p a t i b l e w i t h a d d i t i o n a l a n t i - a r r h y t h m i c d r u g s i f n e c e s s a r y for r e s i s t a n t cases.

f u l t iming, of d e t e r m i n i n g whether s i n g l e or m u l t i p l e s t i m u l i are n e c e s s a r y and of b e i n g u s e d i n a f u l l y a u t o m a t i c mode.

Dur ing a t a c h y c a r d i a s i g n a l s are t r a n s m i t t e d by s k i n

C l i n i c a l e x p e r i e n c e v i t h t h e u n i t has been e x c e l l e n t and

The c o n t r o l box i s c a p a b l e of remembering last s u c c e s s -

0

Tit,e:

Author(s): J.C.P. Cr i ck , E. Sowton

ATRIAL SIGNALS FROM A NEW PACING LEAD WITH MULTIPLE ATRIAL POLES

Address: Guy's H o s p i t a l . London, United Kingdom.

S e n s i n g a t r ia l a c t i v i t y for "phys io log ica l " c o n t r o l o f v e n t r i c u l a r p a c i n g h a s , u n t i l now, u s u a l l y r e q u i r e d t h e i n s e r t i o n o f a separate a t r i a l l e a d . A s i n g l e l e a d wi th a second p o l e i n t h e a t r i u m may p rov ide inadequa te a t r i a l signals f o r r e l i a b l e d e t e c t i o n by s t a n d a r d s e n s i n g c i r c u i t s u n l e s s i t s d e s i g n e n s u r e s con t inuous c o n t a c t w i th t h e a t r ia l w a l l . One approach t o o b t a i n i n g r e l i a b l e c o n t a c t s i g n a l s is t o use two or more a t r i a l p o l e s connected t o g e t h e r , bu t t h e e l e c t r o g r a m from s u c h a c o n f i g u r a t i o n and the r e q u i r e d s e n s i n g c h a r a c t e r i s t i c s have n o t p r e v i o u s l y been examined i n d e t a i l .

m u l t i p l e s e n s i n g e l e c t r o d e s and have developed a new l e a d wi th three r a d i a t i n g a t r ia l b ranches , each b e a r i n g a n e l e c t r o d e a t t h e t i p . A t r i a l e l e c t r o g r a m s r eco rded from such e l e c t r o d e s i n humans have been a n a l y s e d and used t o t e s t t h e a t r ia l s e n s i n g f u n c t i o n of e x t e r n a l and implant- a b l e p u l s e g e n e r a t o r s . P rov ided t h e e l e c t r o d e s were l y i n g i n the r i g h t a t r i u m , a t r ia l s i g n a l s were of g r e a t e r than 1 mV o v e r a l l ampl i tude b u t had a complex and v a r y i n g morphology, c o n s i s t i n g of two or t h r e e i d e n t i f i a b l e i n t r i n s i c o i d d e f l e c t i o n s each o f 0.5 mV ampl i tude or more - t y p i c a l l y 0.8 - 2.5 mV wi th slew rate6 0.25 - 1.2 v o l t s / s ec .

p r o v i d e a t r i a l t r i g g e r e d v e n t r i c u l a r p a c i n g i n p a t i e n t s w i th complete h e a r t block.

We have i n v e s t i g a t e d t h e t h e o r e t i c a l behav iour o f

The l e a d s have been implan ted and used s u c c e s s f u l l y t o

7itle: PROGRAMMABLE PACEflAKER FOR HEARTRATE CONTROLLED CAP.0-

Author(S): E . ZERBST ,H.-E. KORALEI,!SKI , T . PETERS & G . SCHILLING') T l D S I F l U S N E R V E STI11ULATION.

Dept .Physio1 .F ree U n i v e r s i t y B e r l i n blest and

Address*)Dept. Ca rd io l . U n i v e r s i t y Bonn, F R G .

k h e a r t b e a t i n t e r v a l ( H I ) c o n t r o l l e d , b a t t e r y powered mini- a t u r i z e d e x t e r n a l s t i m u l a t i o n u n i t i s r a d i o f r e q u e n c y coup- l e d w i t h an implanted receiver which i s connected t o b i l a t e - r a l implanted c a r o t i d s i n u s ne rve s t i m u l a t i o n e l e c t r o d e s . An e l e c t r i c a l programmable memory (EPROM) in t h e s t i m u l a t i o n u n i t c o n t r o l s ampl i tude and f r equency modulat ion o f t h e s t i - mula t ion impu l ses a c c o r d i n g t o t h e momentary HI o f t h e pa- t i e n t . The HI i s d e t e c t e d by means of ECG-electrodes which a re i n t e g r a t e d i n t h e s t i m u l a t i o n t r a n s m i t t e r antenna and connected t o a s p e c i a l ECG-amplifier which i s p a r t of t h e m i n i a t u r i z e d s t i m u l a t i o n u n i t . According t o t h e t h e r a p e u t i - ca l needs o f p a t i e n t s w i t h hype r t ens ion a n d l o r co rona ry hear t d i s e a s e a s p e c i a l set of d i f f e r e n t HI -co r re l a t ed s t i - mulat ion programs are s t o r e d i n t h e EPFOM. Thus each h e a r t bea t e l i c i t e s a s t i m u l a t i o n impulse t r a i n which has been found by an o p t i m i z a t i o n p rocedure and i s f i t t e d w i t h i t s i n t e n s i t y s c a l e t o t h e h e a r t r a t e c h a r a c t e r i s t i c o f t h e in - d i v i d u a l p a t i e n t s r e sponse t o r e s t and workload c o n d i t i o n s . Therby t h e dosage o f e lectr ical c a r o t i d s i n u s ne rve stimu- l a t i o n i s c o r r e l a t e d t o t h e a c t u a l sympa the t i c and vagal a c t i v i t y o f t h e c a r d i a c ne rves ( r e f l e c t e d by h e a r t r a t e ) . When t h e h e a r t r a t e i s low, t h e r e i s no s t i m u l a t i o n of t h e c a r o t i d s i n u s nerves, and a s the h e a r t r a t e o f t h e p a t i e n t i s inc reased by work load o r emotional f a c t o r s a t h r e s h o l d is reached a t which the f i r s t " low d o s i s " s t i m u l a t i o n enhances t h e c a r o t i d s i n u s ne rve i n t r i n s i c a c t i v i t y . W i t h i n - c r e a s i n g h e a r t r a t e , each R-wave t r i g g e r s s t i m u l a t i o n t r a i n s wi th graded and i n c r e a s i n g i n t e n s i t y ( ampl i tude and f r equen- c y ) . The s e t p o i n t o f t h r e s h o l d and t h e s l o p e o f the s-shaped h e a r t r a t e I s t i m u l a t i o n i n t e n s i v c h a r a c t e r i s t i c i s programmed accord ing t o t h e t h e r a p e u t i c a l needs o f t h e i n d i v i d u a l p a t i e n t . T h u s s t i m u l a t i o n enhances a c t i v i t y i n t h e ba ro re - c e p t o r a f f e r e n t s t h e r e b y i n c r e a s i n g vagal a c t i v i t y and inh ib - i t i n g sympa the t i c a c t i v i t y o f t h e c a r d i o v a s c u l a r c e n t e r . T h u s t h e feed back ne rve pacemaker a s s i s t s t h e n a t u r a l baro- r e c e p t o r s w i thou t t h e wel l known s i d e e f f e c t s o f d rug t h e r a p y .

Title. PERMANENT CARDIAC PACING AFTER OPEN-HEART SURGERY - A 2 2 YEAR REVIEW

Authorb): T. H i l l , J. Pym, B. Goldman, G . Rosen tha l , H. S c u l l y , -R. Weisel, R . B a i r d .

Toronto Genera l Hospital, Toron to , Canada. ' From 1958-1980. 7 5 1 2 p a t i e n t s (pts) underwent open-hea r t s u r g e r y ; 130 p t s ( 1 . 7 % ) r e q u i r e d permanent c a r d i a c pacing from 0 days ( i n t r a - o p e r a t i v e ) to 19 y e a r s a f t e r pr imary repair. P rocedures a s s o c i a t e d w i t h s i g n i f i c a n t conduc t lon d i s t u r b a n c e s were: v a l v e r ep lacemen t s ( V R ) - a o r t i c VR (48/ 130 .37%) . m i t r a l VK (26 /130 ,21%) , a o r t i c and m i t r a l VR ( 5 / 1 3 0 , 3 % ) , m i t r a l and t r i c u s p i d VR (15 /130 ,11%) , a o r t i c , m i t r a l and t r i c u s p i d VR ( 7 / 1 3 0 , 5 % ) ; co rona ry a r t e r y bypass (20/130,16%): c o n g e n i t a l (9 /130 .7%) . The m a j o r i t y o f p t s paced e a r l y were e i t h e r pacemaker dependen t o r had ECG in - d i c a t i o n s a l o n e . L a t e r i m p l a n t s were performed for sympto- m a t i c conduc t ion d i s t u r b a n c e s . The ma jo r i n d i c a t i o n s were s i n u s node d y s f u n c t i o n ( 2 9 pts , 2 2 % ) , i n t e r m i t t e n t complete or i ncomple t e h e a r t b l o c k ( 8 4 p t s , 6 6 % ) , and f a s c i c u l a r b l o c k s (11 pts, 8 % ) . Three p t s had d rug induced b rady- c a r d i a and two p t s had r e c u r r e n t v e n t r i c u l a r t a c h y c a r d i a . A t t h e t i m e of fol low-up, 99 p t s (76%) a r e a l i v e . There wexe no p a c e r r e l a t e d d e a t h s . Pac ing modes u t i l i z e d were f i x e d r a t e (5 p t s ) ( i n e a r l y y e a r s ) , v e n t r i c u l a r demand (123 p t s ) , and a t r i a l t r i g g e r e d ( 2 p t s ) . Lead s y s t e m s were e p i - c a r d i a l i n 26 p t s ( 2 0 % ) and endoca rd ia1 i n 104 p t s ( 8 0 % ) . Surv iv ing pts r e q u i r e d 77 o p e r a t i o n s t o m a i n t a i n p a c e r func- t i o n o r l e a d i n t e g r i t y d u r i n g t h i s t h e . Of s u r v i v i n g p t s , 2/3 a r e a p p a r e n t l y p a c e r dependen t , 1 /3 may n o t now r e q u i r e pac ing . Only 3 p t s have had pacemaker e x p l a n t s . Conc lus ion : Permanent c a r d i a c pac ing h a s been r e q u i r e d i n 1.7% of p t s unde rgo ing open-hea r t s u r g e r y , most commonly a o r t i c VR (48/130)-3.9% of t o t a l a o r t i c V R s . E t i o l o g y of l a te conduc t ion problems and d e c i s i o n f o r e x p l a n t s a r e d i f f i c u l t t o a s s e s s . The cost of pacemaker hardware and fol low-up have s u r p a s s e d t h e c o s t o f t h e o r i g i n a l c a r d i a c r e p a i r .

215


Title: In vitro masurerrents of sensing properties of pacder electndes

Author(s1: R.?hull and M. Schaldach

Address: Zentralinstitut fiir Bimdizinische Mnik mtr. 5, 8520 Erlangen, F.R. G e m y

Leads w i t h screw-in or hwk electrcdes s a n e t h s shm disturbances i n sensing a t r i a l or ventricular ptentials. Tne ccrmrrnly Used expe-tal set-up for in-vim investigations has as d r d a c k s the imposibilities 1. to judge sensing behaviour on simulated tirre dependent R- or P-wave p ten t ia l s . 2. t o find out the changes in the spectral content of both signals af ter passing the electrolyte/ electrode interface,& 3. t o simulate the P-or R-wave

properly. 'Ihe disadvantages were overcun? with an optimized

cel l . To carpare different types of a t r i a l and ventricular e lec t rdes and t o calculate the type specific polarization impedance urder sensing ccnditions a rectanyular pulse w a s applied, controlled in front of the electrode surface. The results shm that sme electrode have f i l t e r characteristics which influence the spectral content i n a way which

explain the sensing loss smetirres observed in vim.

Tltle:Relaticmship between Charge, n t m i t y and~mount of Bone Fozmed by D i r e c t Current Electrical Osteogenesis Author@) : J.Black, C.T.Brighton, Z.B. Friedenbery

Address: Department of O r t k p a d i c Surgery, university of Pennsylvania, Philzdelphia, PA, USA

I t was t h e purpose o f t h e experiments reported, here t o examine t h e r e l a t i o n s h i p between charge , c u r r e n t d e n s i t y and t h e amount of new bone formed i n t h e medullary c a n a l of t h e i n t a c t r a b b i t t i b i a . Experiments were done u t i l i z i n g a s t randed s t a i n - l e s s steel ca thode , a s c r e e n anode and an a d j u s t - a b l e c o n s t a n t c u r r e n t power supply d e l i v e r i n g a f i x e d peak c u r r e n t of 20 microamperes h u t w i t h , varying i n t e r v a l s an-d f r e q u e n c i e s of i n t e r r u p t l o n . R e s u l t s i n d i c a t e t h a t t h e amount of new bone formed by 2 1 days of s t i m u l a t i o n i s r e l a t e d t o a t r u e CUT- r e n t d e n s i t y which is v e r y much g r e a t e r t h a n t h e apparent geometr ic d e n s i t y . d e n s i t y t h e amount o f bone formed is l i n e a r l y r e l a t e d t o t h e t o t a l i n t e g r a t e d charge:

Bone = 0 . 4 l ( c h a r g e ) % + 3.32% (r2= 0 . 9 6 )

A t a g i v e n c u r r e n t

coulombs

This r e s u l t i n g r e l a t i o n s h i p p r e d i c t s , w i t h a high l e v e l of s i g n i f i c a n c e , bo th t h e amount of bone formed by a c o n s t a n t ( u n i n t e r r u p t e d ) c u r r e n t of t h e same f i x e d peak v a l u e a s w e l l a s t h e trauma- t i c a l l y s t i m u l a t e d bone format ion t h a t r e s u l t s i n t h e absence o f c u r r e n t .

i m p l i c a t i o n s on t h e aspects of e l e c t r i c a l s t imula- t i o n systems' des ign f o r t h e promotion of f i x a t i o n of implants and d e v i c e s by b i o l o g i c a l ingrowth.

The r e s u l t s of t h i s s t u d y have c o n s i d e r a b l e

7itle: NEW DEVELOPMENTS OF STIMULATION-UNITS FOR

Aufhor(s). H. StEhr , U. L c s e r t , 3 . Metznlk,

Address: 2nd S u r g i c a l C l i n i c , Vienna, A u s t r i a

ELECTRO-THERAPY O F SCOLIOSIS

G . P f l i iger , H . Thoma

Appl ica t ion of e l e c t r o s t i m u l a t i o n f o r therapy of s c o l i o s i s i s a d i s c u s s i b l e a l t e r n a t i v e t o t h e commonly used Milwaukee-corset. I n s e v e r a l s e r i e s of animal experiments on sheep we t e s t e d d i f f e r e n t t y p e s of completely implantab le s t i m u l a t i o n u n i t s and e l e c t r o d e s up t o one year . I n a l l c a s e s d o r s a l muscles were s t i m u l a t e d d i r e c t l y by means of sc rew-e lec t rodes . I n f i r s t experiments we used 8-channel s t i m u l a t i o n u n i t s . These u n i t s d i d n o t have an own b a t t e r y , s t i m u l a t i o n energy a s w e l l a s in format ion about s t i m u l a t i o n c u r r e n t and r e p e t i t i o n r a t e was t r a n s - m i t t e d i n d u c t i v e l y by means of a c o i l p o s i t i o n e d o u t s i d e on t h e s u r f a c e of t h e body. I n an o t h e r s e r i e s of experiments s i z e of t h e supply u n i t f o r t h e implanted s t i m u l a t i o n u n i t s was reduced so i t was p o s s i b l e t o s t r a p i t around t h e a n i m a l ' s body. Aiming a t a c l i n i c a l a p p l i c a t i o n s t i m u l a t i o n u n i t s needing no manipula t ion a t a l l a r e p r e f e r a b l e . So we developed u n i t s wi th incorpora ted l i th ium- b a t t e r i e s . Capac i ty of b a t t e r i e s a l lows a p p l i - c a t i o n f o r one y e a r approx. S t i m u l a t i o n s t r e n g h can be programmed f r o m o u t s i d e t h e body by means of amagnet . The u n i t has i t s own t imer . I n a c y c l e of 2 4 hours s t i m u l a t i o n i s switched on f o r 9 hours ( 2 sec. s t i m u l a t i p n impulses , 6 sec . i n t e r r u p t i o n ) . I n our animal exper iments we measured bending of t h e s p i n e of 1 1 up t o 27 degrees . But c l i n i c a l r e s u l t s a r e n o t q u i t e s a t i s f a c t o r y a t p r e s e n t .

e o Title:

Author(?+): M. Conrad Huffstutler, Jr.,

Address: Inver Grove Heights MN 55075

TACHYCARDIA TOLERANCE OF HEART VALVES

Medical Incorporated

Healthy, natural heart valves operate efficiently over a wide range of beat frequencies and cardiac outputs (60 to 140 beats per min, 3 to 1 2 literslmin). Efficient operation over this wide range entails rapid opening/closing processes and low rates of closed-position back-leak. In the c a s e of an artificial heart valve, the device must work not only under these load transients but also perform reliably under additional constraints due to valve disease and conduction disorders (arythmia, tachycardia and ventricular fibrillation). A technique has been developed to measure and compare the relative tolerance of heart valves t o high or irregular beat frequencies. For a well-designed mechanical valve the non-dimensional flow r e s i s t a n c e , 4 , is well behaved according to the Blasius law. Unique valve configurations which nef been designed according to fluid principles can exhibit significant deviations from this ideal behavior. Figure 1 pre- sents schematic illustrations of typical<anomalies which can be observed in heart-valve testing. Certain valve designs characterized by low( v a l u e s and a negative slope exhibit excellent tolerance to the combination of low flow and hi h beat rate The Omniscience valve meets these criter- iajtes! data on virious valves will he presented.

SIZE SCALING

EMPIRICAL

\DESIGNED 125+20mml

NR.

4

OSCILLATIONS

FIXED

R.

216

May 1981 0

Communications 0

Title: FATICUE AND CREEP MEASUREMENTS ON PLASTIC FRAMES

Author@):

Address: Cepartment of Su rge ry , C a r d i o t h o r a c i c I n s t i t u t e ,

FUR TlSSUE HEART VALVES

P J mury, w H wain , B w Richa rds , D N ROSS

2 B e a u m n t S t r e e t , London W1N 2DX, England

The p o t e n t i a l f o r creep i n p l a s t i c f l e x i b l e f rames used f o r s u p p r t i n g b i o l o g i c a l h e a r t va lves h a s been s t u d i e d u s i n g frames des igned f o r ( a ) f a s c i a l a t a v a l v e s and ibi c a l f pe r i ca rd ium va lves . R e s i s t a n c e to c r e e p was s t u d i e d in vitm by s e q u e n t i a l measurements o n frames undergoing c y c l i c a l a c c e l e r a t e d f a t i g u e tes ts a t 40 Hz w i t h a d e f l e c t i o n o f 2 mm. P h o t o g r a m e t r i c measuxements were also made on a modif ied p l a s u c f a s c i a l a ta frame removed t e n y e a r s a f t e r i m p l a n t a t i o n which showed o n l y 0 .84 rmn c r eep a f t e r t e n yea r s . An unused f a s c i a l a t a frame showed no c r e e p a f t e r t e n y e a r s s t o r a g e b u t an unnwdi f i ed frame developed 2.0 mm c reep i n 3.2 y e a r s e q u i v a l e n t t i m e o n the a c c e l e r a t e d f a t i g u e t e s t . I n c o n b a s t , a p l a s t i c pericardium v a l v e frame h a s shown no d e t e c t a b l e c r e e p a t t e n y e a r s e q u i v a l e n t t i m e (400 m i l l i o n c y c l e s ) .

These results show t h a t changes i n des ign c a n a f f e c t the c r e e p p o t e n t i a l o f a frame and it is concluded t h a t t h e pe r i ca rd ium v a l v e frame, w i t h no d e t e c t a b l e c r e e p o v e r a t e n y e a r e q u i v a l e n t test, s h o u l d be f r e e of creep for a t l eas t t e n y e a r s o f c l i n i c a l i m p l a n t a t i o n and p o s s i b l y f o r t h i r t y y e a r s by e x t r a p o l a t i o n from the f a s c i a l a t a frame r e s u l t s .

0

Title:

Author(s): C . R. G e n t l e . P. D. Swa les ,

~ d d ~ ~ ~ ~ : Nottingham, U.K. Leeds, U.K.

T e s t i n g o f a n All-Ceramic Mitral Valve P r o s t h e s i s

T ren t P o l y t e c h n i c , and U n i v e r s i t y o f L r e d s

The u s e of a l u n i n a f o r o r t h o p a e d l c p r o s t h e s e s is becoming widespread because o f t h e m a t e r i a l ' s e x c e l l e n t biocompat- i b i l i t y and wear r e s l s t a n c e . However a lumina h a s no t so f a r been used i n va lve p r o s t h e s e s , even though o t h e r ce ramics have Seen sugges t ed f o r c a r d i o v a s c u l a r a p p l i - cations. T h i s is presumably because e x i s t i n g d e s i g n s of va lves would be t o o f r a g i l e i f s imp ly reproduced i n any ceramic m a t e r i a l . The pu rpose o f t h i s pape r is t o r e p o r t t h e t e s t i n g o f a twin f l a p mitral va lve whose d e s i g n h a s made i t s u i t a b l e for c o n s t r u c t i o n comple t e ly i n a lumina.

The v a l v e body is e s s e n t i a l l y a s h o r t c o n i c a l t u b e which p rov ides a n i n h e r e n t s t r e n g t h , i n s p i t e o f t h e b r i t t l e n e s s of t h e a lumina , even wi th t h i n w a l l s . Medical g rade alumina is u s e d , w i th a n i n d i c e d p o r o s i t y of a b o u t 17 p e r cen t . This u t i l i s e s t h e p r o p e r t y o f a lumina , observed i n h i p j o i n t s , t o form a t h i n t i s s u e cove r ing which becomes f i r m l y anchored i n t h e p o r e s .

I n s i d e t h e ccne a r e two s e m i - e l l i p t i c a l occ lud ing f l a p s each mounted on two s t u b a x l e s . These a r e a g a i n o f ceramic but bo th po rous and non-porous forms a r e under i n v e s t i g a t i o n . T i s s u e c o v e r i n g is produced, a l t h o u g h p r o v i s i o n is made f o r wip ing of t h e a x l e s a t each p u l s a t i o n t o p r e v e n t an> bu i ld -up o f thrombus.

Ea r ly an ima l t r ia l s i n d i c a t e good mechanical f u n c t i o n , good flow p rope r t : . c s , l o w haemolysis and no r equ i r emen t f o r con t inued a n t i coagu la t ion .

Title: Roblem of kasmemnt in Heart Valve in Vitro Evalwtion

Author(s): W B Tindale, T R Martin, R van Noort, H M Black.

,,ddress : Departrent of M i d Physics 6 C l i n i c a l Engimering Royal Hallanshire Hospital, Clffisop W, Sheffield, LK

Steady flow testing represents the ms t CnmMlly used technique for cmpra t ive valve walmtion. This pper p-esents m distrnbing findings i n relation to tk w e of steady flow p-essuce hop msurements. The p-essure h o p wzoss tk valve bas masurd i n a unique i n vitco test faci l i ty in ~ c h thz test valve Wured into a Pansparent, f l d b l e , a m t o m i d l y shaped mdel a u t i c rmt. This a s x e s that valves ace m a d not according to the m f a c m e r ' s quoted tissw &us diamtec bx according to &at size valve can be mrrectly f i t ted into tk available cr i f ice of tk aort ic test section. 'Ih test r i g is designed to &liver flow rates up to a oahlmna of 25 Umin d that the velodty p-ofile a t the enmance to the valve test section is blunt ad Iamim. effects of tk followLng factors (11 the p-essure h o p acrffis tk valve w e hestigatd; tk aortic root gwoetry, a b n g e in tk daurstr-eam p-essure -wring s i t e ard a m e in valve orientation. b resul ts slow that a l l these factors h e a significant effect cn the masurd p-essure drop a d can te related t o the velocity mimosnuctrne as miderred by flow visualisation studies. In prt idar, the results &.an wo bdl ad cage valves (Starr+dkmds d s 1260 a d 24m) irdicate that p-evicusly published results my te misleadirg. I n a l l , thirteen different t p s of valve wze waluated. 'he rmclusions ace; it is impxtant t o test valves according to t hek actual tissue arnulus k t e r ; the p-essure h o p m o s s the valve wt k s p c i f i d , not m l y a t different f l w rates bt also for a variety of test chmbx g e m t r i e s a d p-essure aeasming sites, since the relative perforwrre is dependent u p these factors.

Title: EARLY EXPERIENCES WITH THE S T . JUDE MEDICAL VALVE PROSTHESIS I N 4 0 0 PATIENTS

Author(s): HANNEKUM, A . , H . D a l i c h a u , F.W. H e h r l e i n ,

Address: D e p a r t m e n t C a r d i o v a s c u l a r S u r g e r y H. L u b b i n y , H.H. Scheld

U n i v e r s i t y H o s p i t a l s C o l o g n e a n d G i e B e n

F r o m F e b r u a r 1 9 7 8 t o D e c e m b e r 1 9 8 0 4 3 2 p a t i e n t s w e r e operated for v a l v u l a r les ions a t t h e U n i v e r - s i t y Hospi ta l s C o l o g n e a n d G i e R e n u s i n g t h e S t . Jude Medical V a l v e P r o s t h e s i s (SJMVP) . 4 0 0 pa- t i e n t s w e r e available for c l i n i c a l follow-up stu- d i e s 2 t o 36 months a f t e r s u r g e r y (mean of 1 6 , 9 m o n t h s ) w i t h a t o t a l t i m e a t r i s k o f 6 7 7 1 p a t i e n t months. As one could expect w i t h regard t o t h e f u l l ope- n i n g of t he l e a f l e t s and the cen t r a l f l o w c h a r a c - t e r i s t ics of t h i s n e w p ros thes i s , h e m o d y n a m i c r e s u l t s as w e l l a s t h r o m b o e m b o l i c r i s k w e r e s u p e - r io r t o other a r t i f i c a l hea r t valves. 9 1 p a t i e n t s w e r e r e i n v e s t i y a t e d h e m o d y n a m i c a l l y 2 - 2 1 m o n t h s a f t e r valve r e p l a c e m e n t s h o w i n g m e a n pressure g r a d i e n t s o f 3 , 9 5 1 , 2 nun Hy a t rest i n a o r t i c p o s i t i o n and 0 , 8 + 0 , 3 nun Hy a t res t i n m i t r a l p o s i t i o n respectively w i t h no s i g n i f i c a n t correlat ion t o valve s i z e . T h e i n c i d e n c e of throm- b o e m b o l i c c o m p l i c a t i o n s a m o u n t e d t o 0 ,89 % / pa t i en t /yea r e q u i v a l e n t t o 0 , 9 e v e n t s per 100 pa- t i e n t years. F o r f i n a l s t a t e m e n t s on t h e p e r f o r m a n c e of t h e SJMVP m o r e l ong t e r m observations have t o be a c c u m u l a t e d , b u t c e r t a i n l y t h e ea r ly c l i n i c a l r e s u l t s are very p r o m i s i n g .

217

Artificial Organs 0

Vol. 5, No. 2

0

T , ~ ~ ~ :

AuthorW: P. Baurschmidt, R. Ebert and M. Schaldach

Hydrodynamic performance o f a two-di r e c t i o n a l curvature r u t i l e h e a r t valve

Z e n t r a l i n s t i t u t fur Biomed. Technik Uni. ERLANGEN, 0-8520 Erlangen. Turns t r . 5

Title: Hemodynamics o f f o u r new p r o s t h e t i c heart valves

Author@): J. K'ohler, G. Ehrentraut, B. Stormer

Address: Aerodynamisches I n s t i t u t . RWTH, Templergraben 55, D 5100 Aachen

A i m o f t h e i n v e s t i g a t i o n was the comparison o f the hemodynamical behaviour o f t h e Bjork-Shi ley/cc - (BScc), t h e Omni- science-(OS), t h e Hall-Kaster-(HK) and t h e St.Jude Medical- va lve (SJM) i n a o r t i c pos i t ion .

The mockc i rcu la t ion w i t h an e l a s t i c v e n t r i c l e - and a o r t i c - model was descr ibed i n 1978. For twelve valves o f t h r e e d i f - fe ren t s izes - t e x t i l e r i n g diameter 0 by s t e p the pump frequency was increaxe i from 42/min up t o 150/min and the s t roke volume from 30 cm3 up t o 75 cm3 (card iac output CO : 1.5 l / m i n t o 8 l l m i n ) . The pressure loss a p , t h e pressure l o s s c o e f f i c i e n t the e f f e c t i v e va lve &a A were measured and ca lcu la ted respec t ive ly . The volume l o s g o f the valve c losure V the leakage volume V were d e t e n i n e d under the d i%rent pump cond i t ions f o r bach va lve type and s ize .

The BScc-, 0s- and SJM-valve lead t o a considerable lower pressure loss than t h e BS-valve w i t h a plane d i s c (BS). The HK-valve r a r e l y shows an improvement. For DT = 27 mn the SJM-valve shows t h e lowest pressure loss, f o r DT = 29 m t h e OS-valve. j o i n e d w i t h t h e l a r g e s t value o f A,. .For CO> 5 l /minAp, o f the BScc-valve i s about 10 t o 20% higher. Except the HK-valve, t h e new va lve types show an increase o f A, o f about one h a l f (BScc) up t o one f u l l s ize-s tep (0S.SJM) o f t h e o l d BS-valve. The volume l o s s per beat YE i n general increases s lowly with t h e va lve s i z e and decreases with growing CO. Ex- t remely h igh values o f VR = V K ~ + VL were measured a t the SJM-valves o f each s i z e BScc- and the HK-valve they were V 3 6 and 3,7 cm' r e - spec t ive ly . The lowest backf low v o 8 u k $, = 2.1 cm' showed the OS-valve. With smal ler pressure load by new valves t h e backflow volune may ge t a more important f a c t o r i n the c l i n i c a l d iscussion from a hemodynamical and hemorheological p o i n t o f view.

25;27;29 mm - step

and

and

(up t o lg%, V R = 4.7 cml). For the

~ i t l ~ : "Flows near by cardiac p r o s t h e t i c valves"

Author(s): A. BOUSQUET - O.P. L Y - 0. BELLET - H. BOCCALON Groupe de Rheologie - P. PUEL

Address: IMFT - 2 , rue C. Camichel - 31071 TOULOUSE FRANCE

The present work concerns the r e s u l t s obtained by use o f a t e s t i n g device o f cardiac p r o s t h e t i c valves. Fol lowing a t h e o r i c study about s i m p l i f i e d f lows near valves, an experimental device has been b u i l t a l low ing t h e t e s t o f t h e behaviour and t h e hydrodynamic e f f e c t s o f var ious types o f e x i s t i n g cardiac valves . A q u a l i t a t i v e s i g h t o f these researchs i s shown by a f i l m on which one sees w i t h p rec ise d e t a i l s the evo lu t ions o f the complex f lows near these p r o t h e t i c valves, owing t o t h e use o f modern methods o f v isua- l i s a t i o n as the technique us ing hydrogen bubbles. The use o f a cardiac s imu la to r al lows t o ob ta in f lows very s i m i l a r t o those observed i n the a r t e r i a l system.

This experimental approach leads t o q u a l i t a t i v e con- c lus ions which a l low t o guide an opt imal choice o f the valve t o implant t o the p a t i e n t w i thout ambigui ty.

The design o f an a r t i f i c i a l hear t valve w i t h a s y m t r i c a l opening has resu l ted i n an improved hydrodynamic per fo r - mance and a reduc t ion i n sheer stresses due t o normal ly non-uniform f low ra tes . Incorpora t ing ru t i le -ceramics as the mater ia l , i t i s expected t h a t the mechanically i n i t i - ated damage and the a c t i v a t i o n o f b lood components are g rea t ly reduced. The use o f a hinge-type va lve permits an eccent r i c movement dur ing the opening phase w i t h the b e n e f i t o f an o r i f i c e r a t i o o f almost one, i n cont ras t t o c u r r e n t l y used t i l t i n g d isc valves w i t h values on ly as low as 2.5. The ou t -o f -ax is -curva t ion o f the d i s c enhances the opening and c l o s i n g torque moments, thus compensating the l o s s due t o the lead ing edge o f the valve be ing p a r a l l e l t o the main f low. I n order t o minimize the r e g u r g i t a t i o n a l f low, the hydrodynamic res is tance has been enhanced f o r the onset o f the d i a s t o l i c f l o w . The v a r i a b i l i t y o f the vary ing curva t ion charabter o f the d i s c leads t o a s tab le opening angle o f 82 a l l f low rates dur ing s y s t o l i c phase and a sens i t i ve , f a s t a c t i n g c losure.

f o r

0

Title: ADSORPTION RATE OF DIFFERENT HEMOADSORBENTS FOR IMPORTANT TOXIC DRUGS

Author(s1: S . G o t t s c h a l 1 , D . F a l k e n h a q e n , E . S c h r n i t t , H . K l i n k m a n n

U n i v e r s i t y R o s t o c k /CDR Address: D e p a r t m e n t of M e d i c i n e of the W.Pieck-

5 d l f f c r e n t h e m a d e o r b e n t s are l n v e s t l e a t c d In "leu of the adsaro-

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Ph T.

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30 30 30 30 30 3 0 28 30 18 22 2 1 30 30 3 0 28 30

2h s h w=. 17 16 12 10 12 12 15 1 0

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2 0 22 13 1 3 15 14 18 13

Sh N o r i t RBXl 2h s h 15 22 2 0 3 0 11 18 18 2 3 1 0 15 15 2 0 12 15

5 10

UD-4 2h sh 18 2 0 15 16 22 23 21 2 3 18 2 5 30 30 25 28 12 I 4

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21 8

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