aagbi guidelines neuraxial and coagulation
DESCRIPTION
naxTRANSCRIPT
November 2013
Regional Anaesthesia and Patients with Abnormalities of Coagulation
Published byThe Association of Anaesthetists of Great Britain & IrelandThe Obstetric Anaesthetists’ Association Regional Anaesthesia UK
This guideline was originally published in Anaesthesia. If you wish to refer to this guideline, please use the following reference:
Association of Anaesthetists of Great Britain and Ireland, Obstetric Anaesthetists’ Association and Regional Anaesthesia UK. Regional anaesthesia and patients with abnormalities of coagulation. Anaesthesia 2013; 68: pages 966-72. This can be viewed online via the following URL: http://onlinelibrary.wiley.com/doi/10.1111/anae.12359/abstract
Guidelines
Regional anaesthesia and patients withabnormalities of coagulation
The Association of Anaesthetists of Great Britain& IrelandThe Obstetric Anaesthetists AssociationRegional Anaesthesia UK
Membership of the Working Party: W. Harrop-Griffiths,T. Cook,1 H. Gill, D. Hill,2 M. Ingram, M. Makris, S. Malhotra,B. Nicholls,3 M. Popat, H. Swales2 and P. Wood
1 Royal College of Anaesthetists2 Obstetric Anaesthetists’ Association3 Regional Anaesthesia UK
SummaryConcise guidelines are presented that relate abnormalities of coagula-tion, whether the result of the administration of drugs or that of path-ological processes, to the consequent haemorrhagic risks associatedwith neuraxial and peripheral nerve blocks. The advice presented isbased on published guidelines and on the known properties of anti-coagulant drugs. Four separate Tables address risks associated withanticoagulant drugs, neuraxial and peripheral nerve blocks, obstetricanaesthesia and special circumstances such as trauma, sepsis and mas-sive transfusion.
© 2013 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of
The Association of Anaesthetists of Great Britain and Ireland.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License,
which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial
and no modifications or adaptations are made.
1
....................................................................................................
This is a consensus document produced by expert members of a WorkingParty established by the Association of Anaesthetists of Great Britain &Ireland, the Obstetric Anaesthetists’ Association and Regional AnaesthesiaUK. It has been seen and approved by the elected Councils/Committees ofall three organisations.
Accepted: 4 June 2013
• What other statements are available on this topic?Guidance publications on regional anaesthesia in patients taking anti-coagulant or thromboprophylactic drugs are widely available, twowell-known guidelines having been published by the American Societyof Regional Anesthesia and Pain Medicine (ASRA) [1] or adopted bythe European Society of Regional Anaesthesia and Pain Therapy(ESRA) [2].
• Why was this guideline developed?The available published guidance focuses on neuraxial blockade inpatients receiving drug therapy specifically aimed at modifyingcoagulation, but does not address non-neuraxial regional blockade orpatients with abnormalities of coagulation for other reasons. Cur-rently available guidelines are lengthy and discursive, and do notlend themselves to use in the acute clinical setting. The remit of theWorking Party that produced these guidelines was to create a concisedocument that considered regional anaesthesia of all forms andabnormalities of coagulation of both therapeutic and pathologicalorigins.
• How does this statement differ from existing guidelines?Although based on the available guidance and on published pharma-cokinetic and pharmacodynamic data pertaining to anticoagulantdrugs, this guidance is considerably more concise.
• Why does this statement differ from existing guidelines?These guidelines were developed in order to make useful and conciseguidance available to anaesthetists in the clinical setting.
Anaesthetists are often faced with the question of whether the risks of regio-nal anaesthetic techniques are increased when performed on patients with
2 © 2013 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of
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Anaesthesia 2013 W. Harrop-Griffiths et al. | Guidelines: patients with abnormalities of coagulation
abnormalities of coagulation and, if so, whether they are so increased thatthe techniques should be modified or avoided. This is not only because thepopularity of regional anaesthesia is on the rise but also because the use ofanticoagulant drugs in the prevention of venous thromboembolism isexpanding, as is the number of different drugs in use. The serious complica-tions of regional anaesthesia in patients without abnormalities of coagula-tion are very rare indeed [3]. For example, in the third National AuditProject (NAP3), the incidence of vertebral canal haematoma after neuraxialblockade was 0.85 per 100 000 (95% CI 0–1.8 per 100 000). The extent towhich the risk of haemorrhagic complications is increased in patients withabnormalities of coagulation is unquantifiable, but likely to be small. Therarity of the complications means that it is difficult to make accurate esti-mates of the incidence of complications related to abnormalities of coagu-lation, and therefore offering patients and clinicians advice on the basis of‘hard data’ is not possible, and is unlikely ever to become possible. Weare therefore reliant on expert opinion, case reports, case series, cohortstudies and extrapolations from drug properties such as the time taken toachieve peak plasma levels and the known half-lives of drugs.
Published clinical guidance in relation to the risk associated with regio-nal anaesthesia in patients with abnormalities of coagulation is often bin-ary. For instance, it is often said that the performance of neuraxial block ina patient with < 75 9 109.l�1 platelets is not acceptable, whereas its perfor-mance in the presence of > 75 9 109.l�1 platelets is acceptable. However,there can be no relevant difference in risk or outcome after neuraxialblockade in two patients, one of whom has a platelet count of 74 9 109.l�1
and the other 76 9 109.l�1. Risk is a continuum that runs from ‘normalrisk’ to ‘very high risk’, and this guidance seeks to emphasise this point.This guidance must be interpreted and used after consideration of anindividual patient’s circumstances. None of the advice in this guidanceshould be taken as being prohibitive or indicative. An abnormality ofcoagulation – however severe – is always a relative contraindication tothe use of a regional anaesthetic technique. However, there may be cir-cumstances in which, although the use of a regional technique for apatient with abnormal coagulation may put the patient at significant riskas a result, the alternative for this patient (often a general anaesthetic)may expose them to even greater risk. Experienced clinicians should beinvolved in decisions about whether or not to perform a regional anaes-thetic technique on a patient with abnormal coagulation, and the patientwith capacity should be given all the information he/she needs to makean informed choice.
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W. Harrop-Griffiths et al. | Guidelines: patients with abnormalities of coagulation Anaesthesia 2013
Table
1Recom
mendation
srelatedto
drugsused
tomod
ifycoagulation.
Recom
mendedminim
umtimes
arebasedin
mostcircum
-stanceson
timeto
peak
drug
effect
+(elim
inationhalf-life9
2),afterwhich
time<¼
ofthepeak
drug
levelwill
bepresent.Fo
rthose
drugswho
seaction
sareun
relatedto
plasmalevels,this
calculationis
notrelevant.Dataused
topo
pulate
this
Table
arederivedfrom
ASR
AandESR
Aguidelines
[1,2
]andinform
ationprovided
bydrug
manufacturers.These
recommendation
srelate
prim
arily
toneurax-
ialblocks
andto
patients
withno
rmal
renalfunction
except
where
indicated.
Drug
Tim
eto
peakeffect
Elimination
half-life
Acceptable
timeafter
drugforblock
perform
ance
Administration
ofdrugwhile
spinalorepidural
catheterin
place
1
Acceptable
timeafterblock
perform
ance
orcatheter
removalfor
nextdrugdose
Heparins
UFH
scprophylaxis
<30min
1–2
h4hornorm
alAPTTR
Caution
1h
UFH
ivtreatm
ent
<5min
1–2
h4hornorm
alAPTTR
Caution2
4h
LMW
Hsc
prophylaxis
3–4
h3–7
h12h
Caution3
4h3
LMW
Hsc
treatm
ent
3–4
h3–7
h24h
Notreco
mmended
4h4
Heparinalternative
sDanaparoid
prophylaxis
4–5
h24h
Avo
id(consideranti-Xa
leve
ls)
Notreco
mmended
6h
Danaparoid
treatm
ent
4–5
h24h
Avo
id(consideranti-Xa
leve
ls)
Notreco
mmended
6h
Bivalirudin
5min
25min
10hornorm
alAPTTR
Notreco
mmended
6h
Argatroban
<30min
30–3
5min
4hornorm
alAPTTR
Notreco
mmended
6h
Fondaparinuxprophylaxis5
1–2
h17–2
0h
36–4
2h(consideranti-Xa
leve
ls)
Notreco
mmended
6–1
2h
Fondaparinuxtreatm
ent5
1–2
h17–2
0h
Avo
id(consideranti-Xa
leve
ls)
Notreco
mmended
12h
Antiplateletdrugs
NSA
IDs
1–1
2h
1–1
2h
Noadditionalprecautions
Noadditional
precautions
Noadditional
precautions
Aspirin
12–2
4h
Notreleva
nt;
irreve
rsible
effect
Noadditionalprecautions
Noadditional
precautions
Noadditional
precautions
Clopidogrel
12–2
4h
7days
Notreco
mmended
6h
Prasugrel
15–3
0min
7days
Notreco
mmended
6h
Ticagrelor
2h
8–1
2h
5days
Notreco
mmended
6h
Tirofiban
<5min
4–8
h6
8h
Notreco
mmended
6h
Eptifibatide
<5min
4–8
h6
8h
Notreco
mmended
6h
Abciximab
<5min
24–4
8h6
48h
Notreco
mmended
6h
Dipyridamole
75min
10h
Noadditionalprecautions
Noadditional
precautions
6h
Oralantico
agulants
Warfarin
3–5
days
4–5
days
INR≤1.4
Notreco
mmended
Aftercatheter
remova
l
o
4 © 2013 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of
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Anaesthesia 2013 W. Harrop-Griffiths et al. | Guidelines: patients with abnormalities of coagulation
Table
1.(Continu
ed)
Drug
Tim
eto
peakeffect
Elimination
half-life
Acceptable
timeafter
drugforblock
perform
ance
Administration
ofdrugwhile
spinalorepidural
catheterin
place
1
Acceptable
timeafterblock
perform
ance
orcatheter
removalfor
nextdrugdose
Rivaroxa
banprophylaxis5
(CrCl>30ml.min
�1)
3h
7–9
h18h
Notreco
mmended
6h
Rivaroxa
bantreatm
ent5
(CrCl>30ml.min
�1)
3h
7–1
1h
48h
Notreco
mmended
6h
Dabigatranprophylaxisortreatm
ent7
(CrCl>80ml.min
�1)
0.5–2
.0h
12–1
7h
48h
Notreco
mmended
6h
(CrCl50–8
0ml.min
�1)
0.5–2
.0h
15h
72h
Notreco
mmended
6h
(CrCl30–5
0ml.min
�1)
0.5–2
.0h
18h
96h
Notreco
mmended
6h
Apixabanprophylaxis
3–4
h12h
24–4
8h
Notreco
mmended
6h
Thrombolyticdrugs
Alteplase,anistreplase,
reteplase,streptokinase
<5min
4–2
4min
10days
Notreco
mmended
10days
UFH
,un
fraction
ated
heparin;
sc,subcutaneous;APTTR,activatedpartialthromboplastintimeratio;
iv,intravenou
s;LM
WH,low
molecular
weightheparin,
NSA
IDs,
non-steroidalanti-inflam
matorydrugs;IN
R,internationalno
rmalised
ratio;
CrC
l,creatinine
clearance.
Notes
toaccompanyTable
11The
dangersassociated
withtheadministrationofanydrug
thataffectscoagulationwhileaspinalor
epiduralcatheterisin
placeshou
ldbe
considered
carefully.T
hereare
limited
dataon
thesafetyof
theuseof
thenewer
drugsin
thisTable,and
they
arethereforeno
trecom
mendedun
tilfurther
databecomeavailable.The
administrationof
thosedrugswho
seentryin
thiscolumnismarkedas
‘caution
’may
beacceptable,but
thedecision
mustb
ebasedon
anevaluation
oftherisksandbenefitsof
administra-
tion
.Ifthese
drugsaregiven,thetimes
identified
inthecolumnto
theleft(‘Acceptabletimeafterdrug
forblockperformance’)shou
ldbe
used
asaguideto
theminim
umtimethatshou
ldbe
allowed
betweendrug
administrationandcatheterremoval.
2Itiscommon
forintravenou
sun
fraction
ated
heparinto
begivenashorttimeafterspinal
blockade
orinsertionof
anepidural
catheter
during
vascular
andcardiac
surgery.
Localclinical
governance
guidelines
shou
ldbe
followed
andahigh
indexof
suspicionshou
ldbe
maintainedifanysignsattributable
tovertebralcanal
haem
atom
adevelop.
3Lo
wmolecular
weightheparins
arecommon
lygivenin
prop
hylactic
dosestwicedaily
aftersurgery,
butmanyclinicians
recommendthat
only
onedo
sebe
given
inthefirst24
hafterneuraxialblockade
hasbeen
performed.
4Con
siderincreasing
to24
hifblockperformance
istraumatic.
5Manufacturerrecommends
cautionwithuseof
neuraxialcatheters.
6Tim
eto
norm
alplatelet
function
rather
than
elim
inationhalf-life.
7Manufacturerrecommends
that
neuraxialcathetersareno
tused.
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W. Harrop-Griffiths et al. | Guidelines: patients with abnormalities of coagulation Anaesthesia 2013
Table 2 Relative risk related to neuraxial and peripheral nerve blocks inpatients with abnormalities of coagulation.
Block category Examples of blocks in category
Higher risk Epidural with catheterSingle-shot epiduralSpinalParavertebral blocks Paravertebral block
Lumbar plexus blockLumbar sympathectomyDeep cervical plexus block
Deep blocks Coeliac plexus blockStellate ganglion blockProximal sciatic block (Labat, Raj, sub-gluteal)Obturator blockInfraclavicular brachial plexus blockVertical infraclavicular blockSupraclavicular brachial plexus block
Superficialperivascularblocks
Popliteal sciatic blockFemoral nerve blockIntercostal nerve blocksInterscalene brachial plexus blockAxillary brachial plexus block
Fascial blocks Ilio-inguinal blockIlio-hypogastric blockTransversus abdominis plane blockFascia lata block
Superficial blocks Forearm nerve blocksSaphenous nerve block at the kneeNerve blocks at the ankleSuperficial cervical plexus blockWrist blockDigital nerve blockBier’s block
Normal risk Local infiltration
Notes to accompany Table 2There have only been 26 published reports of significant haemorrhagic complications of peripheral nerve andplexus blocks [1]. Half of these occurred in patients being given anticoagulant drugs and half in patients withnormal coagulation. Patient harm has derived from:• Spinal haematoma after accidental entry into the spinal canal during attempted paravertebral blocks asdefined in the Table.
• Exsanguination.
• Compression of other structures, e.g. airway obstruction, occlusion of major blood vessels or tissue ischaemia.
The one death in this series was that of a patient on clopidogrel who underwent a lumbar plexus block andsubsequently exsanguinated. The majority of the 26 cases underwent deep blocks or superficial perivascularblocks. From these data, and from other data relating to neuraxial blocks, we have placed blocks in the order ofrelative risk shown in the Table.Catheter techniques may carry a higher risk than single-shot blocks. The risk at the time of catheter removal
is unlikely to be negligible.Ultrasound-guided regional anaesthesia, when employed by clinicians experienced in its use, may decrease
the incidence of vascular puncture, and may therefore make procedures such as supraclavicular blocks safer inthe presence of altered coagulation.
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Anaesthesia 2013 W. Harrop-Griffiths et al. | Guidelines: patients with abnormalities of coagulation
Table
3Relativerisksrelatedto
neuraxialblocks
inobstetricpatients
withabno
rmalitiesof
coagulation.
Riskfactor
Norm
alrisk
Increasedrisk
Highrisk
Very
highrisk
LMWH
–prophylactic
dose
LMWH
–therapeuticdose
>12h
>24h
6–1
2h
12–2
4h
<6h
6–1
2h
<6h
UFH
–infusion
Stopped>4hand
APTTR≤1.4
APTTRabove
norm
alrange
UFH
–prophylactic
bolusdose
NSA
ID+aspirin
Last
given>4h
WithoutLM
WH
Last
given<4h
WithLM
WH
dose
12–2
4h
WithLM
WH
dose
<12h
Warfarin
INR≤1.4
INR1.4–1
.7INR1.7–2
.0INR>2.0
Generalanaesthesia*
Starved,notin
labour,
antacids
given
Fullstomach
orin
labour
Pre-eclampsia
Platelets
>1009
109.l�1
within
6hofblock
Platelets
75–
1009
109.l�1(stable)
andnorm
al
coagulationtests
Platelets
75–1
009
109.l�1
(decreasing)and
norm
alco
agulation
tests
Platelets
<759
109.l�1
orabnorm
al
coagulationtestswith
indices≥1.5
orHELLP
syndrome
Idiopathic
thrombocytopenia
Platelets
>759
109.l�1
within
24hof
block
Platelets
50–7
59
109.l�1
Platelets
20–5
09
109.l�1
Platelets
<209
109.l�1
Intra-uterinefetaldeath
FBCand
coagulationtests
norm
alwithin
6h
ofblock
Noclinicalproblems
butnoinve
stigation
resultsava
ilable
Withabruptionor
ove
rtsepsis
Cholestasis
INR≤1.4
within
24h
Nootherclinical
problemsbutno
inve
stigationresults
ava
ilable
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W. Harrop-Griffiths et al. | Guidelines: patients with abnormalities of coagulation Anaesthesia 2013
LMWH,low
molecular
weightheparin;
UFH
,unfractionatedheparin;
APT
TR,activated
partialthromboplastin
time;NSA
ID,n
on-steroidalanti-inflam
matorydrug;INR,
internationaln
ormalised
ratio
.
*Alth
ough
generalanaesthesiaisno
tarisk
factor
perse
forcoagulationcomplications,itisinclud
edin
thisTable
tohighlight
that
thealternatives
toregion
alanaes-
thesia
areno
tfree
ofrisk;thus
arisk–benefitcomparisonisrequ
ired
whenchoosing
oneover
theother.Seeno
tesbelow.
Notes
toaccompanyTable
3Risks:The
risksareprim
arily
thoseof
vertebralcanalhaem
atom
awithsubsequent
cord
compression
andperm
anentdamage.Realisticalternatives
toepidural
analge-
siaexistin
labour,bu
t,forcaesareansection,
thechoice
isthat
ofgeneralor
neuraxialanaesthesia,
andtherisksof
spinal
haem
atom
ain
patients
withabno
rmal
coagulationmustbe
weighed
againstthoseof
generalanaesthesia,
especially
inpatients
who
arein
labour
andhave
afullstom
ach.
These
risksinclud
ehypo
xaem
iaassociated
withdifficulties
maintaining
theairw
ay,pu
lmon
aryaspiration
andthromboem
bolic
complications.
Lowplatelets:The
debateregardingthesafety
ofneuraxialb
lockadein
wom
enwiththrombocytopeniaisguided
byexpertconsensusop
inionin
theabsenceof
clinicaltri-
als;itisno
tthereforepo
ssibleto
give
definitive
values
foralower
limitatwhich
thereisan
increasedrisk
ofhaem
atom
a.Fo
rno
rmalhealthywom
en,there
isno
increased
risk
ofcomplications
withplatelet
coun
ts>1009
109 .l�
1[4].Acoun
tof
>75
910
9 .l�
1hasbeen
prop
osed
asan
adequate
levelfor
region
alblocks
whenthereareno
risk
factorsandthecoun
tisno
tdecreasing
[5].In
pre-eclampsia,a
decreasing
plateletcoun
tisaccompanied
byothercoagulationabno
rmalities,andthisisassumed
tobe
thecase
once
theplateletcoun
tdecreasesto
below1009
109 .l�
1 .Iftheplateletcoun
tisbelowthisvalue,acoagulationscreen
shou
ldbe
performed
–ifthisisno
rmal,it
wou
ldbe
reason
ableto
perform
aregion
alblockdo
wnto
alevelo
f75
910
9 .l�
1 ,depend
ingon
therateof
decrease
inplateletcoun
t[6].In
idiopathicthrombocytopenic
purpuraandgestationalthrom
bocytopenia,thereareredu
cedplateletnu
mbers,but
norm
alfunction
.Inthesesituations,expertop
inionisthatan
experiencedanaesthetist
might
reason
ably
perform
aneuraxialblockade
providingtheplatelet
coun
tis>50
910
9 .l�
1andstable,bu
tan
individu
alrisk–b
enefitassessmentshou
ldbe
made
[7–11].Itispo
ssiblethat
spinal
anaesthesiawithplatelet
coun
tsbelowthislevelmay
besafe
ifdata
areextrapolated
from
that
derivedfrom
lumbarpu
ncturesin
non-
pregnant
patientsperformed
byhaem
atologistsusingneedlesconsiderablylarger
than
thoseused
byobstetricanaesthetists[9].Astablelevelo
f40
910
9 .l�
1may
besafe
forlumbarpu
ncture
intheabsenceof
othercoagulationabno
rmalities.
The
plateletcoun
tshou
ldbe
checkedbefore
anyneuraxialp
rocedu
reifthereisanysuspicionof
decreasing
plateletnu
mbersdu
ring
routineantenataltesting,signs
ofthe
developm
ento
fpre-eclam
psia,e.g.proteinuriaor
hypertension
,orotherclinicalfeatures
suggesting
coagulop
athy,placentalabruptionor
ifthepatient
hasbeen
givenrecent
anticoagulanttherapy.Plateletnu
mbers
candecrease
inpatientstreatedwith
regularheparinfor>4days.O
therwise,itwou
ldno
tbe
routineto
checkplatelet
numbers
anddelayneuraxialb
lock
whilsttheseresults
areaw
aited.
Itwou
ldbe
standard
practiceto
perform
aneuraxialp
rocedu
rewith
in6hof
thelastplateletcoun
tandclottin
gstud
iesin
patientswith
mild
ormod
eratepre-eclampsia.H
owever,ifthepatienthassevere
orfulm
inatingpre-eclampsiaor
HELL
Psynd
rome,aplateletcoun
tandclottin
gstud
iesshou
ldbe
checkedim
mediatelybefore
performingtheprocedure,as
decreasesin
plateletcoun
tcan
occurrapidlyin
thesecircum
stances.
Low
molecular
weightheparins
withaspirin:
Treatmentwithdaily
LMWH
andaspirin75
mgmay
beencoun
teredwhenfollowingNICEguidelines,which
recom-
mendlow-doseaspirinforobesityor
hypertension
.ProvidedtheLM
WH
isstop
pedfor>12
h,theplatelet
coun
tis>75
910
9 .l�
1andno
rmal
coagulationiscon-
firm
ed,neuraxialblocks
canbe
categorisedas
‘increasedrisk’on
ly.
Intra-uterinefetaldeath:
After
intra-uterinedeath,
thereisan
increasedrisk
ofcoagulop
athy
andsepsis,especially
inthesecond
weekafterfetaldemise.Coagulation
abno
rmalitiescanoccuron
presentation
inabou
t3%
ofwom
enwithapparently
uncomplicated
intra-uterinedeath,
andthis
increasesin
thepresence
ofabruption
oruterineperforationto
arou
nd13%
[12].It
isthereforeprud
entto
checkcoagulationstatus
before
anyregion
alprocedure.
The
onsetof
coagulop
athy
isvariable,
butcanbe
rapid.
Cholestasis:In
obstetriccholestasis,coagulop
athy
may
developas
aresultof
decreasedabsorption
ofvitamin
Kessentialforactivation
ofclotting
factors.Itisim
por-
tant
tocheckcoagulationbefore
region
alblockade,bu
tchangesdo
notoccurrapidly.
Rem
oval
ofepidural
catheters:The
recommendation
sgivenin
Table
1fortheremoval
ofepidural
cathetersshou
ldbe
noted.
8 © 2013 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of
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Anaesthesia 2013 W. Harrop-Griffiths et al. | Guidelines: patients with abnormalities of coagulation
Table 4 Risks of regional anaesthesia in patients with abnormalities ofcoagulation – special circumstances.
Trauma The coagulopathy of trauma is precipitated by tissue trauma,shock, haemodilution, hypothermia, acidaemia andinflammation. Following major trauma, it is recommended thatan assessment of potential coagulopathy be made beforeperforming any regional anaesthetic technique.
Sepsis Severe sepsis is associated with a procoagulant state. Guidelinessupport the use of chemoprophylaxis against deep venousthrombosis. For advice on regional anaesthesia with intercurrentthromboprophylaxis, refer to Table 1. Septic shock may beassociated with the development of a consumptive coagulopathy.Clinically significant systemic sepsis remains a relativecontraindication to central neuraxial anaesthesia due to thepresumed increased incidence of epidural abscess and meningitis.
Uraemia Uraemia may lead to coagulopathy secondary tothrombocytopenia. It is recommended that all patients withsignificant uraemia undergo assessment of platelet number andfunction before regional anaesthesia. Platelet function may beimproved by the administration of DDAVP.
Patients with chronic renal impairment may be managed withregular dialysis. The presence of residual anticoagulation afterheparin administration must be considered in patients afterdialysis, and heparin reversed if indicated. If regionalanaesthesia is performed, the safety of catheter removal mustbe considered in patients likely to receive heparin duringfurther dialysis.
Liver failure All coagulation factors except factor VIII are synthesised in theliver. Liver failure is associated with haemostatic abnormality,the extent of which must be assessed before regionalanaesthetic techniques are performed. There may bethrombocytopenia and abnormal platelet function due toassociated hypersplenism. Patients in liver failure represent ahigh-risk group for general anaesthesia. When regionalanaesthesia is considered as an alternative, coagulopathy mustbe assessed and corrected when indicated.
Massive transfusion Massive transfusion is associated with altered haemostasis, withdilution and consumption of coagulation factors being theprimary causes in this pathophysiological change. In assessingthe degree of coagulopathy before regional anaesthetic techniques,it is recognised that coagulopathy in massive transfusion is adynamic situation. Assessment should be made when haemorrhageis controlled and the patient is cardiovascularly stable. Anassessment of platelet function should ideally occur in patientswho have been given platelet transfusions.
Disseminatedintravascularcoagulopathy
Disseminated intravascular coagulopathy (DIC) is thepathological activation of coagulation mechanisms in responseto a disease process leading to a consumptive coagulopathy.A diagnosis of DIC is incompatible with safe neuraxialblockade. When peripheral blocks are considered, they shouldbe at compressible sites.
Notes to accompany Table 4All of the conditions discussed can, in their ‘active’ state, be associated with significantcoagulopathy. When regional anaesthesia is thought to be of potential value, e.g. for post-operative analgesia, it should be conducted with reference to the guidelines outlined in therest of this publication.
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W. Harrop-Griffiths et al. | Guidelines: patients with abnormalities of coagulation Anaesthesia 2013
Advice is often offered that if regional anaesthesia is to be consid-ered in a patient with a known abnormality of coagulation, an ‘experi-enced anaesthetist’ should perform the procedure. There are, of course,no hard data to support this suggestion. However, it is advice that theWorking Party supports. It is likely that an experienced regional anaes-thetist will need fewer attempts to gain block success, and it is likelythat the complications related to bleeding are in part related to thenumber of attempts at a block. It is reasonable to ask novices to per-form their blocks on patients at ‘normal risk’, reserving attempts inpatients at ‘increased risk’ for experienced clinicians.
Guidance is offered here in the form of four Tables, each withexplanatory notes: Table 1 contains recommendations related to drugsused to modify coagulation; Table 2 suggests the relative risk related tothe performance of neuraxial and peripheral nerve blocks in patientswith abnormalities of coagulation; Table 3 indicates relative risks relatedto obstetric patients; and Table 4 describes risks of regional anaesthesiain special circumstances.
Some readers may question the absence of a section on haematologi-cal conditions associated with abnormalities of coagulation – why do wenot mention Christmas disease or other forms of haemophilia? Most ofthese diseases are the result of the absence or shortage in the body of aparticular clotting factor or group of factors. Most of the patients withhaematological diseases such as these reach surgery in the full knowledgethat they have the disease. The standard treatment of bleeding resultingfrom a deficiency of a clotting factor or other contributor to normal coag-ulation when faced with surgery is the administration of that factor orother contributor after guidance from a haematologist. Therefore, for elec-tive surgery, the solution is almost always the performance of the regionaltechnique after acceptable normalisation of coagulation on the advice of ahaematologist. In the emergency situation, urgent advice should be soughtfrom on-call haematologists.
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