Current Anaesthesia & Critical Care (2003) 13, 287̂ 292�c 2003 Elsevier Science Ltd. All rights reserved.doi:10.1054/cacc.2002.0423

CONTROVERSIES

Cruel to be kind? Regional block before or afterinduction of general anaesthesiaP.D.W.Fettes and J. A.W. Wildsmith

University Department of Anaesthesia,Ninewells Hospital and Medical School,Dundee DD19SY,UK

KEYWORDSanaesthesia, general;anaesthesia, local; safety;paresthesia; complications,neurologic; anaesthesia,epidural

Summary The question of whether to insert regional blocks before or after induc-tion of general anaesthesia is controversial, butthe debate basedmore on opinion thanfact.The arguments for insertion after induction are:

K There is no evidence that it is anymore dangerous.K It leads to greater patient acceptance and comfort.K It provides betterconditions for training.K The practice ismedicolegally acceptable.

The arguments for insertion before induction are:

K Anaesthetized patients cannot report pain or paraesthesia when the block isperformed, or adverse symptoms to testdoses of local anaesthetic.

K Whynotperformthe block ¢rst since this is standardpractice inmanycentres?K Whowillmonitor the patientwhenthe block is performed?

There is no large randomized controlled trial comparing the safety of blocks beforeand afterinductionofgeneral anaesthesia, andit isunlikely thatthere everwillbe. How-ever, a signi¢cant link between pain or paraesthesia experienced on needle insertion,and subsequentnerve damagehas been observed.Also studies usingnerve stimulatorsduringperipheralnerveblockhave shownthatparaesthesiaemaybeexperiencedwith-out motor response. Both of these ¢ndings suggest that nerve block may be safer inawake patients.Although there is no direct evidence that performing blocks on anaesthetized pa-

tients is less safe, there is some indirect evidence to suggest it might be. If a block is tobeperformedonananaesthetizedpatienttheremustbe agoodpositivereasonfor this.�c 2003 Elsevier Science Ltd.Allrights reserved.

INTRODUCTIONThe popularity of regional anaesthesia is probably at anall time high, there having been a substantial and interna-tional increase in the use of regional blocks over the past30 years. But popularity in medicine, as in politics, tendsto wax and wane, and concerns about safety could re-verse this trend. Large surveys have shown that regionalanaesthesia is safe, and that serious complications arerare.However, the complications arepermanent anddis-tressing. Predictably, the increased utilisztion of regional

0953-7112/03/$-see frontmatter

Correspondence to: PDWF.Tel.: +44 01382 632427; Fax: 01382 644914;E-mail: pdwfettes@doctors.org.uk

anaesthetic techniques has been accompanied by an in-crease in the absolute number of cases in which compli-cations have been identi¢ed. There has also been anincrease in the number of claims against anaesthetistsby patients who have received regional anaesthesia,1,2

although there is no evidence that the actual incidenceof complications or claims has risen. It is ironic that, inthe age of evidence-basedmedicine, it is a small numberof high pro¢le cases, rather than the combinedweight oflarge studies, that is more likely to cause regional anaes-thesia to fall from grace. Therefore every factor, whichcould compromise patient safety, must be consideredand reconsidered.

288 CURRENT ANAESTHESIA & CRITICALCARE

In1996, a new factor was identi¢edby aWorld author-ity on regional anaesthesia, Philip Bromage, who pre-sented his views in an editorial entitled ‘Maskedmischief’.3 In the article, Bromage described situationswhere complications could be masked by anaesthesia,or nerve block.One example was the insertion of thor-acic epidural catheters under general anaesthesia thatwas, he said, ‘‘the most £orid form of masked mischief’’.He stated that patients are ‘‘rendered incapable of vocalor re£ex muscular responses to spinal cord impalementand insu¥ation with air.’’ Bromage’s article has triggeredmuch debate over the past few years, mainly based onopinion rather than evidence, but the issue still requiresattention.

THEARGUMENTS ........ for insertion after inductionMost discussion has hinged on whether performing

blocks on anaesthetizedpatients increases the likelihoodof neurological sequelae. Protagonists of this approachargue that there is no evidence that it is any more dan-gerous to do so,4,5 that it leads to greater patient accep-tance and comfort, and that it providesbetter conditionsfor training.5 Paradoxically it has also been stressed thatonly skilled anaesthetists should perform centralblocks,5,6 and few would argue with Fischer’s assertionthat ‘‘themajor factors in preventing neurological seque-lae are the experience and dexterity of the anaesthetist,proper training and supervision of trainees, detailed as-sessment of pre-existing vascular and neurological dis-ease, avoidance of repeated attempts due to technicaldi⁄culties, and prompt recognition and treatment ofcomplications to prevent permanent damage’’.5 Fischerhas also pointed out that two major medical defenceorganizations in the United Kingdom do not view theadministration of a general anaesthetic before a regionalanaesthetic as inherently bad practice.5 Althoughmedicolegal opinion is important, there is a di¡erencebetween optimum management, and what might beconsidered legally defensible, although the gap may benarrowing.. ... for insertion before inductionBromage has highlighted that anaesthetized patients

cannot give a verbalwarning of symptoms of, or producere£ex muscular responses to, pain or paraesthesia. Thelatter assertion is at odds with that of Fischer who be-lieves that re£ex muscle movement will still occur. Afurther concern is that patients will also be unable to re-port any adverse symptoms to test doses of local anaes-thetic for epidural, or indeed any other type of local orregional block. Adverse e¡ectsmaybe systemic (e.g. as aresult of intravascular injection) or local (e.g. uninten-tional subarachnoid injection during epidural block),although the consequencesmay still be systemic.

Bromage and others7,8 have questioned the need toperform blocks on anaesthetized patients given that it isstandard practice in most centres noted for regionalanaesthesia to do them¢rst.This seems perfectly accep-table to patients if a careful technique is used, and asBromage asks: ‘‘why risk the added risk?’’9 A key point isthe question of who monitors the general anaestheticwhile the block is performed, the clear inference beingthat patient safety may be compromised by the ‘distrac-tion’of the block.7While Fischer has argued that there isno good evidence that performing blocks under generalanaesthesia increases the risk, he acknowledges thatthe onus for proving the safety of this approach is on itsproponents.

THEEVIDENCEBASESo, experts in regional anaesthesia are divided in theiropinions on the subject of when to perform the block.But what evidence base is there to help the practitionerdecidewhat to do?

Studies and surveys

There is no large randomized controlled trial comparingthe safety of blocks before and after induction of generalanaesthesia, and it is unlikely that there ever will be. Infact, there are few large surveys examining complica-tions of regional anaesthesia, and none which looks spe-ci¢cally at di¡erences in incidence when the blocks areperformed awake or asleep.What the available studiesdo show is that regional anaesthesia is safe, and that ser-ious complications are very rare. Auroy and colleagues10

looked prospectively at over 100 000 regional anaes-thetics and found the incidence of permanent neurologi-cal de¢cit to be 0.5 in10 000 and the incidence of death tobe 0.9 in 10,000 (other studies have found similar inci-dences11,12).This suggests that any potential di¡erence incomplication rates between blocks performed awake orasleep is likely to be small, and di⁄cult to demonstrate.Therefore, it seems unlikely that large surveys will everprovide a straight answer on whether there is a di¡er-ence in safety between the two approaches.Thus, otherless direct evidencemust be sought to guide practice.What Auroy and colleagues did ¢nd is that there is a

signi¢cant link between pain or paraesthesia experi-enced on needle insertion, and subsequent nerve da-mage. Out of a total of 34 neurological complicationsrecorded in their study, 21 were associated with para-esthesia on needle insertion, or pain on injection. Mostof the rest involved the intrathecal injection of 5% lido-caine suggesting a direct neurotoxic e¡ect, and a di¡er-entmechanism of action. Pain or paraesthesia on needleinsertion have also been found to be risk factors in otherlarge studies, albeit retrospective in nature,1,11,13 and the

CRUELTOBEKIND? 289

implication of this needs to be considered.Would per-forming the block awake be safer if the needle is with-drawn immediately on sensation of pain or paraesthesia,or will the damage have been done already? It doesmakesense that any damage will at least be limited if thepatient is awake, the needle advancedgently, and any dis-comfort taken immediately as a sign of problems.

Case reviews and reports

What value does the presentation of reports on indivi-dual patients have to modern daymedicine? The answeris ‘considerable’ in situations like this where complica-tions are rare and may not be picked up even in large-scale studies. The ‘yellow card’ system for reporting ad-verse drug reactions is a good example of this, and thechair and deputy chair of the Cochrane CollaborativeSteering Group have recognized the limitation of evenlarge-scale trials which unless ‘placed in the context ofother relevant research, exist as islands of information’.They have also recognized that ‘one challenge facing re-viewers today is how to identify and incorporate data onrare adverse events not usually available from rando-mised trials’.14 Unfortunately, because they tend to becarried out by enthusiasts, voluntary surveys rarelyidentify problems, but occasional case reviews and re-ports, anecdotal though they are, may provide impor-tant information.When they are publicized widely, individual cases car-

ry enormous power, as can be seen from the history ofspinal anaesthesia. A case series reported by a Britishtrained, New York based neurologist, coincided withtwo high pro¢le cases in the UK, and led to the virtualdemise of spinal anaesthesia in the middle of the 20thcentury.15More recently, in1994, a reportof twopatientssu¡eringmajor neurological injury after thoracic epidur-al block was published in Germany, and led to the settingup there of what amount to national guidelines.8 Thesestate that general anaesthesia is an absolute contra-indi-cation to thoracic epidural placement, and a relative con-tra-indication to all other central blocks. The guidelinesalso go so far as to suggest that ‘for instance a cholecys-tectomyor a hemicolectomy in an otherwise healthy pa-tient is not considered to be a reasonable indication for athoracic epidural.’In 2001, Reynolds16 published a series of seven patients

su¡ering from spinal cord damage after spinal or com-bined spinal/epidural (CSE) anaesthesia. In all seven pa-tients, there was pain on insertion of the spinal needleand the neurological de¢cit emerged as the block re-gressed, and six of the seven had magnetic resonanceimaging (MRI) evidence of a lesion in the spinal cord at alevel consistentwith the clinical features.Onlyone of thepatients hadpain on injection of local anaesthetic, but allhadpermanentde¢cit.The damage had alreadyoccurred

although the patients were awake. So was patient feed-back useless in preventing damage? This series has beenused to negate the argument that performing blocks inawake patients is safer,17 but did the clinicians simplyignore thewarnings?

Inferential evidence

Tworecentpublications addweight to the argument thatperipheral nerve block is safer if performed awake.FirstChoyce and colleagues,18 and then Urmey and Stanton19

have demonstrated that a motor response cannot al-waysbe elicitedwith a nerve stimulator after thepatienthas reported paraesthesiae. In both studies paraesthe-siae were elicited during brachial plexus block and thenthe nerve stimulator was turned on. A twitch responsedid not occur ato0.5mA in all patients in either study,although there were important di¡erences between thetwo.Urmey and Stanton enlisted 30 patients undergoinginterscalene block for shoulder surgery. After para-esthesiae were obtained, a twitch was observed in only30% of patientswhen the currentwas increased to1mA,there being no relationship between the distribution ofparaesthesiae and the subsequent motor responsealthough 20 out of the 30 needles used were un-insu-lated. No patient required conversion to general anaes-thesia, and the surgeon’s assessment of the block was atleast ‘satisfactory’ or better. Choyce and colleagues en-rolled 72 patients having axillary brachial plexus blockwith un-insulated needles for upper limb surgery, but19 of these were excluded, mostly because of arterialpuncture. In 77% of the remainder a motor responsewas obtained (ato0.5mA) after paraesthesiae. Mediancurrent was 0.17mA, but the range was 0.03^3.3mA,and a relationship between distribution of paraesthesiaeand motor response was found in 81% of patients.Interestingly,13% of blocks required supplementary localanaesthetic, and 9% of patients required conversion togeneral anaesthesia.The two studies showbig di¡erences in both block re-

liability, and the relationship between paraesthesiae andmotor response. These di¡erences are important andmay be explained only partly by di¡erences in block siteand the needles used. However, the important messageis thatparaesthesiaemaybe experiencedwithoutmotorresponse, and both papers concluded that nerve blockwould be safer in lightly sedated or awake patients.

SPECIALPROBLEMSANDGREYAREASThere are a number of special situations where the bal-ance of risk andbene¢tbecomes altered to some degree,and these deserve special consideration.

290 CURRENT ANAESTHESIA & CRITICALCARE

Paediatric anaesthesia

No discussion about the timing of regional block wouldbe complete without consideration of paediatric prac-tice,whereblocks arenowperformedalmostuniversallyafter induction of general anaesthesia.This is because ofthe particular problems of communication and compli-ance in children that virtually dictate that general anaes-thesiamustbeused.This viewwas challengedin1998 by areport detailing the case of a 62-year-oldwoman, with ahistory of previous back surgery, who su¡ered per-manent paraplegia after multiple attempts to site anepidural catheter under general anaesthesia.20 Severalcriticisms were made of the patient’s management,which was complicated by poor treatment of periods ofintra andpostoperative hypotension, andmagnetic reso-nance imaging (MRI) showed both spinal cord infarctionat T5, and gas bubbles in the spinal cord at T10 and T12.However, the authors condemned particularly the ad-ministration of a thoracic epidural in an anaesthetizedpatient, stating that this should only be attempted as alife-savingmeasure in exceptional circumstances. Subse-quently, this conclusion was refuted vehemently by alarge number of paediatric anaesthetistswho stated thatperforming regional anaesthesia on anaesthetized chil-dren is a safe technique.21,22 Of the several articles citedto support their stance, one is particularly worthy ofmention.A prospective French survey23 was carried out over

the course of1year.Data from over 85 000 anaesthetics(a 51% response rate) included 24 409 with a regionalcomponent (89% under GA). Over 60% of these werecentral (mainly caudal) and 38%were peripheral.The re-sultswere interesting.Noperipheral complicationswererecorded at all.The central complication ratewas1.5 per1000, althoughmostcomplicationswererelativelyminor,and none were permanent in nature. The conclusion ofthis impressive study was that regional anaesthesia issafe, but that peripheral blocks are safer than centralones.

Other di⁄cultieswith patient compliance

In paediatric anaesthesia the balance of risk and bene¢tin regionalblock is alteredbecause children are generallyunable fully to comprehend and comply with treatment.It is possible to imagine situations in the adult populationwhere similar conditionsmightprevail, and one such casehas been described by Absalom and colleagues.24 Inser-tion of a thoracic epidural catheter was attempted priorto induction of anaesthesia for emergency abdominalsurgery in an anxious Asian woman with poor English.The patient was lightly sedated, and unrestrained.During local anaesthetic in¢ltration with a 4 cm needle,the patient rolled suddenly onto her back, causing theneedle to advance to its hub, and leaving the patient

with a spinal cord injury. Although the problem mighthavebeen avoided if a needle ofmore appropriate lengthhad been used for in¢ltration, the authors suggest thatperforming the block asleep would have probably beensafer in this instance. They maintain the view, however,that regional blocks are generally safer if performedawake.

The patient in pain

Patientsmaypresent for surgery, particularly emergencysurgery, in severe pain and this will often make theprospect of performing regional anaesthesia prior to in-duction less than appealing.Positioning thepatient for allbut the simplest blocks may be impossible, and thetwitching with a nerve stimulator may add to their dis-tress. In addition, caution must be exercised becausethepatientmaybehypovolaemic, or have some other re-lative contra-indication to central block. Nevertheless,certain patients undergoing emergency abdominal sur-gery may bene¢t from a thoracic epidural once the pro-cedure is over.Does the additional bene¢t of establishinganalgesia ¢rst justify inserting the epiduralbefore thepa-tient regains consciousness? Certainly, the consequenceof spinal cord damage is so severe that any additionalrisk needs justi¢cation, but if the risk is very small,and the bene¢t (high-quality pain relief) so tangible, isthat not justi¢cation in itself? In Germany, the answerwould be a resounding ‘no’. Should it be di¡erentelsewhere?

Uncertain surgery

In some situations it may be di⁄cult to predict the op-eration thatwill be performed on a patient. In some cen-tres, including our own, diagnostic laparoscopy mayprecede, and often obviate the need for, laparotomy.Those that do undergo laparotomy may bene¢t fromthoracic epidural block, particularly in the presence ofrespiratory illness.What should be done in this instance? Should the pa-

tient have an epidural sited prior to induction when itmay prove to be unnecessary? Should the epidural besited under general anaesthesia if laparotomy is per-formed, or should it be sited once the patient is awakeand in pain? Perhaps the easiest option would be toforget the epidural altogether and prescribe PCA mor-phine, but that would not be optimum care for everypatient.Another dilemma, cited by a group of anaesthetists in

Cardi¡,6 is in anaesthesia for thoracic surgery wherebronchoscopy may or may not be followed by thoracot-omy. They use this to justify thoracic epidural insertionunder general anaesthesia, although one alternativesolution is to have separate lists for bronchoscopy and

CRUELTOBEKIND? 291

thoracotomy, and another to use a more peripheralblock technique (e.g. Paravertebral).

SO, AWAKEORASLEEP?The protagonists in this debate are agreed on one thing.Regional anaesthesia must be performed carefully andcautiously by practitioners who have full knowledge ofthe relevant anatomy, the technique being used, its com-plications and theways of avoiding them.Those (the pre-sent authors included) who favour the ‘awake’ approachnote that theprotagonists of the‘asleep’approach acceptthat they have to prove that it is a safe one. They alsohave to be able to answer several questions:

1. Why do the block with the patient asleep?2. Why not do the block with the patient awake?3. Is there an alternative to an invasive procedure on anunconscious patient?

4. Whowillmonitor the patient while the block is beingperformed?

The answer to the‘awake or asleep’questionrelates tothe balance of risk and bene¢t, so proscriptive nationalguidelines such as those in place in Germany, althoughwell intentioned, are probably unnecessary becausethey remove the clinician’s ability to tailor the anaes-thetic to the patient. Anaesthetists would be well ad-vised to perform all blocks in awake or lightly sedatedpatients if at all possible, but there must be a place forthe alternative.This principle is of particular importancefor central blocks where the potential for damageis greatest, but it also applies to peripheral nerve block.In instances where more than one block is used themore peripheral block should be inserted ¢rst wherepossible.Finally, an interesting observationwithwhich to close.

A recent survey of anaesthetists in the Oxford regionhas shown a di¡erence between beliefs and workingpractices.25 While most anaesthetists believed thatblocks were safer performed awake, the majority stillperformed most of their blocks on anaesthetized pa-tients. Instead of being cruel to be kind, is this a case ofbeingkind tobe cruel? It is time to question this anomaly,and practisewhat we believe to ensure the safety of ourpatients.

REFERENCES

1. Cheney F W, Domino K B, Caplan R A, Posner K L. Nerve injury

associated with anesthesia: a closed claims analysis. Anesthesiol-

ogy 1999; 90(4): 1062–1069.

2. Aitkenhead A R. The pattern of litigation against anaesthetists. Br J

Anaesth 1994; 73(1): 10–21.

3. Bromage P R. Masked mischief. Reg Anesth 1996; 21(6 Suppl):

62–63.

4. Gough J D, Williams A B, Vaughan R S, Khalil J F, Butchart E G.

The control of post-thoracotomy pain. A comparative evaluation

of thoracic epidural fentanyl infusions and cryo-analgesia. Anaes-

thesia 1988; 43(9): 780–783.

5. Fischer H B. Regional anaesthesiaFbefore or after general

anaesthesia? Anaesthesia 1998; 53(8): 727–729.

6. Vaughan R S, Gough J D. The control of post-thoracotomy pain: a

reply. Anaesthesia 1989; 44: 445–446.

7. Wildsmith J A. Regional anaesthesiaFbefore or after general

anaesthesia? Anaesthesia 1999; 54: 86.

8. Gruning T. Regional anaesthesiaFbefore or after general

anaesthesia? Anaesthesia 1999; 54: 86–87.

9. Bromage P R. The control of post-thoracotomy pain. Anaesthesia

1989; 44(5): 445–446.

10. Auroy Y, Narchi P, Messiah A, Litt L, Rouvier B, Samii K. Serious

complications related to regional anaesthesia: results of

a prospective survey in France. Anesthesiology 1997; 87(3):

479–486.

11. Aromaa U, Lahdensuu M, Cozanitis D A. Severe complica-

tions associated with epidural and spinal anaesthesias in Finland

1987–1993. A study based on patient insurance claims. Acta

Anaesthesiol Scand 1997; 41(4): 445–452.

12. Horlocker T T, Wedel D J. Neurologic complications of spinal

and epidural anaesthesia. Reg Anesth Pain Med 2000; 25(1):

83–98.

13. Horlocker T T, McGregor D G, Matsushige D K, Schroeder D R,

Besse J A. A retrospective review of 4767 consecutive

spinal anesthetics: central nervous system complications. Peri-

operative Outcomes Group. Anesth Analg 1997; 84(3):

578–584.

14. Clarke M, Langhorne P. Revisiting the Cochrane Collaboration.

Meeting the challenge of Archie CochraneFand facing up to

some new ones. BMJ 2001; 323(7317): 821.

15. Wildsmith J A, Lee J A. Neurological sequelae of spinal

anaesthesia. Br J Anaesth 1989; 63(5): 505–507.

16. Reynolds F. Damage to the conus medullaris following spinal

anaesthesia. Anaesthesia 2001; 56(3): 238–247.

17. Vaughan R S. Pain relief after thoracotomy. Br J Anaesth 2001;

87(5): 681–683.

18. Choyce A, Chan V W, Middleton W J, Knight P R, Peng P,

McCartney C J. What is the relationship between paresthesia and

nerve stimulation for axillary brachial plexus block? Reg Anesth

Pain Med 2001; 26(2): 100–104.

19. Urmey W F, Stanton J. Inability to consistently elicit a

motor response following sensory paresthesia during inter-

scalene block administration. Anesthesiology 2002; 96(3):

552–554.

20. Bromage P R, Benumof J L. Paraplegia following intracord injection

during attempted epidural anesthesia under general anesthesia.

Reg Anesth Pain Med 1998; 23(1): 104–107.

21. Krane E J, Dalens B J, Murat I, Murrell D. The safety of epidurals

placed during general anesthesia. Reg Anesth Pain Med 1998;

23(5): 433–438.

22. Bosenberg A T, Ivani G. Regional anaesthesiaFchildren are

different. Paediatr Anaesth 1998; 8(6): 447-450.

23. Giaufre E, Dalens B, Gombert A. Epidemiology and morbidity of

regional anesthesia in children: a one-year prospective survey of

the French-Language Society of Pediatric Anesthesiologists.

Anesth Analg 1996; 83(5): 904–912.

24. Absalom A R, Martinelli G, Scott N B. Spinal cord injury caused by

direct damage by local anaesthetic infiltration needle. Br J Anaesth

2001; 87(3): 512–515.

25. Kadry M A, Rutter S V, Popat M T. Regional anaesthesia for

limb surgery–before or after general anaesthesia. A survey

of anaesthetists in the Oxford region. Anaesthesia 2001; 56(5):

450–453.

292 CURRENT ANAESTHESIA & CRITICALCARE

FURTHERREADING

Urmey W F. Regional anaesthesia is potentially dangerous in

anaesthetised adult patientsFpro. http://www.esraeurope.org/ab-

stracts/abstracts99/urmey2.htm

Fischer B. Regional anaesthesia is potentially dangerous in anaesthe-

tised patients F con. http://www.esraeurope.org/abstracts/ab-

stracts99/fischer3.htm

Urmey W F, Stanton J. Inability to consistently elicit a motor response

following sensory paresthesia during interscalene block administra-

tion. Anesthesiology 2002; 96(3): 552–554.

Choyce A, Chan V W, Middleton W J, Knight P R, Peng P, McCartney

C J. What is the relationship between paresthesia and nerve

stimulation for axillary brachial plexus block? Reg Anesth Pain Med

2001; 26(2): 100–104.

Krane E J, Dalens B J, Murat I, Murrell D. The safety of epidurals placed

during general anesthesia. Reg Anesth Pain Med 1998; 23(5):

433–438.