1.2 the vitalograph - a study of its role in pulmonary function testing in childhood. j. wolfsdor

8/14/2019 1.2 the Vitalograph - A Study of Its Role in Pulmonary Function Testing in Childhood. j. Wolfsdor

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7 Augustus 1971 S A M E D I E S E T Y D S K R J l F 851

The Vitalograph Study of Its Role Pulmonary

Function Testing in hildhood

J. WOLFSDORF, M.B., B.CH., B 5C DIP. PAED., M.R.C.P.E., Senior Paediatrician Depanmf ?l [ oj Paediatrics u i ~versity of the Witwatersrand AND D J STEVENS, M.SC. (ENG. ), Pneumoconiosis Resewch Unit Clinical

Sciences Division SAMRC o h a n n e s b u r g

SUMMARY.

A dry spirometer (Vitalographt) has been examined inrelation to its mechanical reproducibility, and feasibilityfor use in paediatric pulmonary function testing. Measurements a t ATPS and BTPS indicate a -2 1 0 to + 13 47variability in volume readings respectively. Measurementson 30 4 normal healthy children, aged 6 -1 8 years, height120- 17 4 cm were made using this dry spirometer andstatistically compared with normal available water spirometric data. Except for mid-expiratory flow rates, all c m-pare favourably.

S. Air Med J 45, 851 (1971).

Pulmonary function tests ' should now be performed onevery pa ti en t wi th kn ow n or suspected cardiopulmonarydisease , jus t as haemoglobin determination, blood pressuremeasurement an d urine analysis ar e performed as aroutine. In general, however, laborator ies, equipment an dtechnical staff are expensive. Th e purpose of this study was

to evaluate an easy-to-use cheap dr y spirometer an d delineate an d statistically com pare the results obtained fromits u se in c hil dr en , to available normal values.'

MATERIALS AN D METHODS

Experiment 1

A water sp irometer was connected tightly to a Vitalograph, an d fixed v aryi ng vo lumes (2 litres an d 4 litres)were blown fro m o ne to th e other at ATPS. Ten readingswere measured at each volume.

Experiment 2

Experiment 3

Th e fixed volume respirator then: introduced ai r fullysaturated at 3TC into the Yitalograph via a copper tube112 cm x 19 cm immersed in water at room temperature 2ye . Te n rea di ng s were th en ta ken .

Experiment 4

Twenty-five normal boys, aged 14 - 17 years, mean height175 cm, were u ti lized. Each standing sub ject forc ib ly exhaled through a Wright's peak flow meter, the best of 4readings being taken. Vitii lography an d water spirometrywere then carr ied ou t in a sil l) ilar manner. Mean regressionlines with the ir 95 confidence l imits were calcu la ted forFYC, FEY an d peak an d mid-expiratory f low rates, fo rboth machines, an d then p lot ted and com pared with standard water spirometric data.

Experiment 5

Standing pulmonary funct ion s tudies (FVC, FEV, andMVV) were carried ou t using the Vitalograph alone on279 norma l hea lthy chi ld ren (140 boys an d 139 girls), aged6 - 18 years, mean heights 156 cm and 149 cm fo r boys andgirls respectively. Th e best of 4 r ead ing s w ere an aly se d,compared and presented as above.

RESULTS

Tab le I su mm ari ze s t he resu lts found for ex perim ent s I, 2an d 3 Yitalogniph readings at ATPS consistently underread the water .spirometer readings by 2 10 an d 3'36

A volume-regulated respirator,t w hi ch fully saturatedth e ai r at 37C, was attached first to the water spirometer,an d then to the Vita lograph . A fixed volume was blownalternatively into each spirometer an d recorded. Te n MI ATPSreadings were taken from each instrument.

*Date received: 31 March 1971.tVitalograph Limi ted , Bu ck ing h am, Eng lan d .tDragar Spiromat. ,.

MI BTPS

TABLE SPIROMETER READINGS

Dry Water-dry -

Water mean SO difference Via tube2000 1 957 5 -2 1 04000 3865 0 - 3 3 6

1700 1 930 0 + 13 471 700 ,1785 5 +5 03


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852 S . A . M E D I C A L J O U R N A L 7 August 1971

TABLE 11. CORRELATION COEFFICIENTS. HEIGHT AGAINSTVITALOGRAPH PARAMETERS AN D WRIGHT S PEAK

FLOW METER 279 CHILDREN)

respectively fo r 2- an d 4-litre deflections. At BTPS consistent Vitalograph over-reading (mean 2300 ml) occurred,giving a 4 7 ~ ~inaccuracy. When ai r was d eliv er ed via acopper tube to the Vitalograph, the o ve r- read in g th atoccurred was reduced by 8 4 3 ~ ~to 5-D3 (mean 855 ml).

Table 1I gives the relat ionship of height against Wrightspeak flow meter an d various Yitalograph flow an d volume

p a ramete rs fo r 279 normal children (experiment 5). Exceptfor mid-expira tory flow rate, there is a good corre la t ion in

all measurements. Tab le I II A gives the [ values f or co mparisons of th e mean s tan d ard wa te r sp irometer FY C an dF EY, d at a, to u wate r sp irome try d a ta ; the Vitalographdata c om pa re d t o ou r water spirometric da ta a nd Yitalog ra ph d at a against normal standard water spirometric data(experiment 4).

Table II I B gives the mean f low rates fo r s tan d ard data,an d ou r data utilizing a Wrigh t s p eak flow meter, Vitalograph an d water spirometer ; t value comparisons are ind icated . Wi th th e exception of FMF, the calculated; valuesindicate that no s igni fi ca nt d iffe re nc es e xi st betwe en themeans t value of < 196 fo r the number of degrees of freedo m is en co u nte red mo re th an 5 of the t ime (experiment4).

Figs. I - 6 (a an d b) show t he rel at ions hips betwe en

height an d Wrigh ts p eak flow, an d Vita lograph peak flowF EV, F VC , FMF, an d MVY f or n or ma l boys an d girls.

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110HElGloIT -c.II oIo.

W RI GHT S PE 1l FLO ooI80 15

W R I G H T ~Pv.i . FL oGlIt .LS

OG

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50 0I.

Males Females

PEF 0873 899PEF 717 0820FMF 0 513 0758FEV,.,) 0919 0930FVC 0930 0928MV V 0914 0928

f o r m id e x p i ra t or y f low FMF) ..

Wright s

Vitalograph

* oor cor re lat ions

TABLE III A. COMPARISON BETWEEN WATER SPIROMETER, VITALOGRAPH AND NORMAL DATA. VOLUMES CORRECTED TO BTPS)

Experimental Standardt values

spirometer Vitalograph dataS pi ro me te r Vit al og ra ph Vit al og ra ph

Mean SO Mean SO Mean SO std data spirometer st d dataFEV 45 2076 500 2242 4 5 76 119 0 744 1 106FEV 1 o 37 170 39 1-65 3 8 148 0 243 0 377

TABLE III B. COMPARISON BETWEEN WATER SPIROMETER, VITALOGRAPH A ND N OR MA L DATA. FLOWS lITRES/MIN)

t valuesWright s Vitalograph Spirometer Std data

Wright s Wright s Std dataMean SO Mean SO Mean SO Mean SO Std data Vitalograph st d data Vitalograph

PEF 485 58 485 102 486 49 0025 0 040 0052FMF 240 52 243 89 274 104 1 565 2 54


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7 Augustus 1971 S . - A . M E D I E S E T Y D S K R I F 853

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,90

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1 10

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,50 ~ 110I - lE I G r iT- ' CII l

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Fig. 4a. Vitaiograpb FV C (ATPS--I i tres-boys) .

Fig. 3b. Vitalograph FEV,.o (ATPS--litres-girls) .

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VrTALOG.RAPH FE. V l0G t i l .

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' JITALOGR PH PE ...K. FLOWGIR.L.S

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100

le

Fig. 2a . Vi ta log raph peak flow (litres/min-boys).

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854 S . A . M E D I C A L J O U R N A L 7 August 1971

Fig. Sa. Vitalograph FM F (litres/min-boys).

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Bo s

Fig. 6a. VitaIograph MV V (A TP8-l i t re/min-boys) .

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VlTAI.OGoRAPH FM F.

GIRLS

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F ig . 5 b. Vit al og ra ph FM F (litres/min---girls). Fig. 6b. Vitalogr-aph MY V (ATP8-litre/min-girIs).

TABLE IV. BOYS -VITALOGRAPH vs STANDARD DATA.

VOLUMES-L1TRE/BTPS

Table I V gives the means, standard deviations and values comparing Vitalograph FVC, FEV an d M VV with

Vitalograph Standard data

standard available data for boys. No significant differenceexists be tween the means. A lt ho ug h n o similar data isavailable fo r girls du e to the inccmpleteness of publishedresults, the similarity of their means t o n or ma l data lendsconfidence to the assumption t ha t thei r s tandard deviationsand values would be comparable.

M e an h ei gh t 156 ems.

FVCFEV,oM W

Mean3030

105

SO

1271064

4238

Mean301286

1025

SO

0':4570'448

1403

t value0'04014890662

DISCUSSION

Th e Vitalograph is a low-priced, direct-writing light-weight(5'6 kg) por tabl e (40 x 38 x 24 cm) robust, dr y spirometerwhich utilizes a wedge-type plastic bell (maximum volume


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7 Augustus 1971 S A M E D I E S E T Y D S K R IF 855

6'612 litres BTPS as its volume-measuring member. Inertiaan d resistance ar e compensated fo r by spring forces. Timedvolumes an d flows ma y be measured as recorder speedcom pare s to the time recorded on the graph trace to anaccuracy of 001 seconds. In spite of i ts fai rly widespreaduse in th e USA, Britain an d Africa, only one critical reporton its performance, an d this utilizing adult patients, ha sbeen published. Drew and Hughes have shown thatrecorder speed , ac tiva t ion volume , vo lume ca libra tion an dlinearity accuracy comply well with laid down internationalstandards at A TPS. In a small series using normal adultsthey measured forced vital capacity an d timed expiratoryvolume, an d stated that biological cal ibra tion fo r thesep a ra m et er s w a s good. Res i st ance an d inertia were foundto b e h ig he r than was acceptable , an d they suggested thatflow rates would be inaccurate utilizing this machine.

Th e results reported here show that i n a bs ol ut e t er m s atATPS, volume readings on the Vitalograph are fairlyaccurate. At BTPS however, as ai r is a poor conductor of

. heat as c o m pa r ed w i th w at er , n o i ns ta nt an eo us c or re ct io nto ATPS is possible in th e dr y bellows, an d consistent overreadings ar e recorded. T he e rr or be in g in the o rd er o f 1 fo r every 3 e above ATPS. Th e f ac t t ha t the introductionof a cooled c o pp e r p ip e between th e heated, fully saturatedv o lu m e s ou rc e an d the Vi ta lograph recorder corrects tbis

o ve r- re ad in g t o a s igni fi cant extent, supports the abovepostulate.

In biological terms where sp iromet ry data m a y n or ma l lyvary widely within h ei gh t g ro up s, a 3 over-readingv ar ia bi li ty n ee d not necessarily p re clu de th e use of amachine. The second part of this study which statisticallycompares th e v ar io us v ol um e an d flow values acb ievedusing the Vi ta lograph on normal children an d data wbichhas p rev ious ly been pub li shed, s t rong ly suggests t h at o th ert ha n f or mid-expiratory flow rates, t he Vit al og ra p h m a y befreely used in the routine assessment of pulmonary function in childhood.

We should like to thank Miss D. Meyer, Technician, e-partment of Paediatrics, University of the 'Vitwatersrand, forher invaluable assistance; and the following Heads of Schoolswithout whose co-operation this study could n ot have takenplace: Mrs 1 K Glansfield (Johannesburg High School ~ o rGirls); Miss P. Pentelow (Johannesburg P rep ar ato ry GIrlsSchool); Mr H. R. Corbett (King Edward VII Boys HighSchool) and Mr H. P. Green (Yeoville Boys Primary School) .

REFERENCES

1Comroe, J. H ., Forster, R. E.

ITDu Boi s, A. B., Briscoe, A. an dC ar ls en , E . (1962): Th e u ng 2n d ed. C hi ca go : Yea r B oo k Medical

Publishers.2. Weng, Tzong-Ruey an d Levison, H. (1969): Amer. Rev. Resp. Dis., 99,

879.3. Drew, C. D. M. and Hughes, D. T. D. (1969): Thorax , 24, 703.

oekbesprekings ook eviewsLABORATORY MANUAL

Manual of Laboratory Medicine By A. Brugbera-Jones,M.D. Pp. xiv 363. Illustrated. 10.00. New York: Harper Row. 1970

This book provides a fai rly comprehensive study at a t e h ~ llevel of principles and methods of most tests done by chell1lcalpathology and haematology laboratories Unfortunately .thesubject is treated at a very elementary level and the technicaldiscussion is limited to the performance of those tests that amedical student might be expected to per fo rm during his preclinical training years. While the book cou ld serve as a usefulreference manual for studen ts, it is generally preferable thatteaching depar tment s use works that conform to their own

par ti cu la r sy llabus and , for this reason , it is~ o u b t f u l

t ha t thetext would have much appeal in South Africa. It IS clearlymuch more suited to the Amerit;an training system than ourown.

B.B.D.

M ED IC AL C A RE IN CONTRASTED SETTINGSMedicine in Three Societies A comparison of medical carein the USSR USA and UK. By J. Fry, M.D. (Lond.),F.R.CS. (Bng.'), F.R.C.G.P. Pp. ix 249. ~ y ~ e s b u r yMTP. 1970. Obtainable from Cotton Hardle, Pmelands,Cape.

This appraisal of medical services offered .in a socialist state,capitalist environment and an in-between sltllabon accentuates

the distinct po ten tial for over-all medical care in cont ras tedsettings.

Th e Russian program of medical training-from feldsherto specialist-is particularly illuminating, as are the numerousstatistics comparing the 3 medical systems. Dr Fr y obviouslydoes not approve of the trends in American medicine.

The way the book has been compiled unfortunately leads toneedless repetition of some initially very interesting facts.

G.D.

CUTIS HYPERELASTlCA

Th e Ehlers Danlos Syndrome By P. Beigbton, M.D.,M.R.C.P. (LoncL), M.R.C.P. (Bd.), D.e.H., D.T.M. H. Pp. 194. Illustrated. 3.15. London: William HeinemannMedical Books. 1970.

Cutis hyperelas tica deserves more attention from the medicalprofession than from onlookers at circus sideshows. Th e bizarrephysical attributes of those affected c loak a Widespread abnormality, apparently of collagen, which involves many tissues.At least 5 var iant s of th is heritable disorder are recognizednow and serious complications may arise in t he gravis an decchymotic types.

Written in Dr Beighton 's unmistakable style, this usefu lreference book provides an exhaustive review of the EhlersDanlos' syndrome an d includes much orig inal work and a comprehensive bibliography.

D.A.W.

1.2 the vitalograph - a study of its role in pulmonary function testing in childhood. j. wolfsdor

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