Ilioinguinal nerve block for orchidopexy

Correspondence

Ephedrine/Epinephrine druglabel confusion

When the European Commission’s deci-sion [1] to require the UK to label drugswith their ‘recommended InternationalNon-proprietary Name (rINN)’ was firstpublicised, there were fears that errors andconfusion would result [2, 3]. In particu-lar, the potential for confusion between‘Epinephrine’ (adrenaline) and ‘Ephe-drine’ was mentioned [4]. That has nowbeen reported, to our anaesthetic incidentaudit, twice in one day, from neighbour-ing operating theatres.

An enthusiastic operating departmentpractitioner was aware of the newnomenclature. When the syringe labelsfor adrenaline ran out, concerned toavoid the confusion with atropine, heordered labels reading epinephrine. Twicein one day, anaesthetists who used ephe-drine for treating hypotension labelledtheir syringes ‘epinephrine’. In one case,the error was only recognised when thesyringe was being discarded. Neitherpatient came to any harm. The erroroccurred despite a circular letter, sent toall anaesthetic staff some months earlier,drawing their attention to the newnomenclature. Appeals to ‘read the label’[5] will always fail sometimes, as it is wellknown that we read by recognising wordshapes, not their individual letters. Hope-fully, as we learn the new shape, the errorswill become rarer. Good publicity atthe time of any change would seemimportant. Meanwhile, beware!

R. Hugh JamesLeicester Royal Infirmary,Leicester LE1 5WW, UK

References1 Council directive on the labelling of

medicinal products for human use andon package leaflets. Official Journal ofthe European Communities 1992; L113(31 March): 8–12 (92/27/EEC).

2 George CF. Naming of drugs: pass theepinephrine, please: confusion overinternational differences may putpatients at risk. British Medical Journal1996; 312: 1315–6.

3 Navarro FA. Naming of drugs. BritishMedical Journal 1996; 313: 688–9.

4 Nunn DS, Baird WLM. Ampoulelabelling. Anaesthesia 1996; 51: 1–2.

5 Nunn DS. Avoiding drug errors: readthe label. British Medical Journal 1995;311: 1367.

Thoracic epidural analgesia andcoronary artery bypass graftsurgery

We read with interest the recent retro-spective analysis in which Turfrey et al.(Anaesthesia 1997; 52: 1090–5) reporteda lesser incidence of arrhythmias afterthoracic epidural analgesia in patientsundergoing coronary artery bypass graftsurgery. Broadly similar beneficial resultsincluding earlier extubation, attenuatedcatecholamine response, improved post-operative analgesia and pulmonary func-tion have been shown by several otherauthors using thoracic epidural analgesia[1, 2]. Despite the purported potentialbenefits, it needs to be emphasised thatonly few authors recommend routineuse of this technique.

In the above study the epiduralcatheter was inserted immediately

before induction of anaesthesia and priorto full systemic heparinisation while inmost other studies the catheters wereplaced at least 12–24 h before scheduledsurgery [1–3]. It raises concern as to thesafety of inserting the catheter only 1–2 h before systemic heparinisation. Todate there has been no report of epiduralhaematoma in patients receiving epi-dural analgesia for coronary arterybypass graft; nevertheless, it needs to beacknowledged that there is such a risk.Spinal haematoma has been reported inmany cases in whom diagnostic lumbarpuncture was followed by intravenousheparin within an hour [4] and recentlyin a patient associated with intra-opera-tive use of heparin [5]. No matter howmeticulous the technique with whichthe epidural space is invaded, the inci-dence of bloody tap – in the order of 1–11% [6] – needs considered evaluation.In the absence of predictability of adifficult or traumatic procedure andhence the risk of epidural haematoma,it would seem prudent to delay surgeryfor 24 h in such an event to ensure safetyof the patients and to avoid the risk ofsuch a devastating consequence.

We are at a loss to understand howethics committee approval and informedconsent were obtained for this retro-spective study. Did the authors mean aroutine consent for surgery as againstone specifically to study the effects ofepidural analgesia in this group ofpatients?

Prospective randomised controlledtrials have failed to show any real advan-tage in terms of outcome and recoveryparameters conferred by the addition ofthoracic epidural anaesthesia to medium

Anaesthesia, 1998, 53, pages 511–517................................................................................................................................................................................................................................................

511Q 1998 Blackwell Science Ltd

All correspondence should be addressed to Dr M. Morgan, Editor of Anaesthesia, Department of Anaesthetics, Royal Postgraduate Medical School,Hammersmith Hospital, London W12 0HS, UK.

Letters (two copies) must be typewritten on one side of the paper only and double spaced with wide margins. Copy should be prepared in the usualstyle and format of the Correspondence section. Authors must follow the advice about references and other matters contained in the Notice toContributors to Anaesthesia printed at the back of each issue. The degree and diplomas of each author must be given in a covering letter personally signedby all the authors.

Correspondence presented in any other style or format may be the subject of considerable delay and may be returned to the author for revision. If theletter comments on a published article in Anaesthesia, please send three copies; otherwise two copies of your letter will suffice.

or lower dose opioid-based general anaes-thesia in patients undergoing coronaryartery bypass graft [7–9]. Similar earlierstudies have shown that patients receiv-ing epidural infusion for intra- and post-operative analgesia exhibited significantlyincreased pulmonary artery wedgepressure [10], significant decrease inarterial blood pressure and in coronaryperfusion pressure [11] and suppressedcortisol response [12] when comparedwith patients without epidural analgesia.The authors could have analysed theseissues in their epidural group in order toevaluate objectively the benefits of thistechnique. We feel that the risks, albeitrare, of spinal haematoma and paraplegiaare to be taken more seriously.

A. MallickN. C. BhaskaranRoyal Hallamshire Hospital,Sheffield S10 2JF, UK

References1 Chaney MA. Intrathecal and epidural

anesthesia and analgesia for cardiacsurgery. Anesthesia and Analgesia 1997;84: 1211–21.

2 Meibner A, Rolf N, Van Aken H.Thoracic epidural anesthesia and thepatient with heart disease: benefits,risks and controversies. Anesthesia andAnalgesia 1997; 85: 517–28.

3 Mollhoff T, Loick HM, Mullejans B,Rolf N, Van Aken H. Totalintravenous versus combinedanesthesia. Effects on early extubationafter coronary artery bypass grafting(CABG). Anesthesiology 1997; 87:A122.

4 Ruff RL, Dougherty JH.Complications of lumbar puncturefollowed by anticoagulation. Stroke1981; 12: 879–81.

5 Rabito SF, Ahmed S, Feinstein L,Winnie AP. Intrathecal bleeding afterthe intraoperative use of heparin andurokinase during continuous spinalanesthesia. Anesthesia and Analgesia1996; 82: 409–11.

6 McNeill MJ, Thornburn J.Cannulation of the epidural space, acomparison of 18 and 16 gaugeneedles. Anaesthesia 1988; 43: 154–5.

7 Fillinger MP, Dodds TM, Yeager MP,Brinck-Johnson T, Glass DD. Effectsof thoracic epidural anesthesia and

analgesia on recovery after coronaryartery bypass graft surgery. Anesthesiaand Analgesia 1995; 80: SCA32.

8 Fillinger M, Yeager M, Dodds T,Fillinger M, Whalen K, Glass D.Thoracic epidural analgesia doesnot alter outcome and recovery aftercoronary artery bypass surgery.Anesthesiology 1997; 87: A113.

9 Thorelius J, Ekroth R, Hallhagen S,et al. Thoracolumbar epiduralblockade as adjunct to high dosefentanyl/midazolam anesthesia incoronary surgery: effects ofsternotomy. European Journal ofCardiothoracic Surgery 1996; 10:754–62.

10 Stenseth R, Bjella L, Christensen O,Levang OW, Gisvold SE. Thoracicepidural analgesia in aortocoronarybypass surgery. 1: Haemodynamiceffects. Acta AnaesthesiologicaScandinavica 1994; 38: 826–33.

11 Stenseth R, Berg EM, Bjella L,Christensen O, Levang OW, GisvoldSE. Effects of thoracic epiduralanaesthesia on coronaryhaemodynamics and myocardialmetabolism in coronary bypasssurgery. Journal of Cardiothoracicand Vascular Anesthesia 1995; 9:503–9.

12 Moore CM, Cross MH, DesboroughJP, Burrin JM, Macdonald IA, HallGM. Hormonal effects of thoracicextradural analgesia for cardiacsurgery. British Journal of Anaesthesia1995; 75: 387–93.

In one of the earliest clinical reports ofcardiopulmonary bypass for cardiac sur-gery, a combined epidural and generalanaesthetic technique was employed forone of the patients [1]. Yet, in the fourdecades since this report, the use ofepidural anaesthesia for cardiac surgeryhas found little favour in clinical practice[2]. Recently, there has been an upsurgeof interest in this controversial tech-nique. Unfortunately, we fear the paperby Turfrey and colleagues (Anaesthesia1997; 52: 1090–113) may have donemore to muddy, than clarify, thecontroversy.

Our concerns are the result of thestudy’s methodology and statistical ana-

lysis. Retrospective dredging of data,which is a notorious source of error, wasemployed by Turfrey and co-workers.Using a 5% level of probability, one in 20variables will be significant by chanceand this factor could have contributedto their findings. Another drawback toanalysing retrospective data is that itlacks the control of binding. It is wellrecognised that ‘the investigators naturalenthusiasm for a new treatment may wellinfluence his judgment of the patientsprogress and may also be transmitted tothe patients and affect their well being,especially for conditions where symp-toms are subjective, such as the degree ofpain’ [3]. Turfrey and colleagues findingof an earlier extubation time in theepidural group may well be a reflectionof their enthusiasm for thoracic epiduralanaesthesia. An even more serious dan-ger of reviewing data retrospectively isthe absence of randomisation which isessential to prevent patient selection biason the part of the anaesthetists. If theanaesthetists had been less willing to useepidurals on sicker patients, e.g. thosewith unstable angina, then this may wellhave produced the difference in rates ofarrhythmias. Indeed, the fact that patientswith abnormal coagulation studies, pre-sumably due to anticoagulation, wereexcluded from the combined epiduraland general anaesthetic, but not thegeneral anaesthetic group, supports thisview. With regards to the statisticalanalysis, it is unclear from the resultswhether a correction for multiple test-ing, such as Bonferroni’s, has beenapplied. If not, then simple multipli-cation of the probability (0.02) for thedifference in the rates of arrhythmiasbetween groups by the number ofvariables (n� 11) gives a nonsignificantvalue of 0.22. Given these flaws, it isneither possible to draw any valid con-clusions from this study nor has it estab-lished the need for a large, prospective,randomised study.

Our major misgiving regarding theuse of epidurals for cardiac anaesthesia iswhether the benefits of the techniqueoutweigh the drawbacks. When assess-ing the benefits, cardiac anaesthetistsshould be mindful of high-dose opioidanaesthesia which had many putativebeneficial effects but failed to improve

Correspondence Anaesthesia, 1998, 53, pages 511–517................................................................................................................................................................................................................................................

512 Q 1998 Blackwell Science Ltd

outcome of surgery [2]. On the otherend of the balance is a catastrophicdrawback and that is paraplegia resultingfrom an epidural haematoma. Undoubt-edly, Ruff and Dougherty have found anassociation between diagnostic lumbarpuncture and epidural haematoma whichis compounded by traumatic puncture,early anticoagulation and aspirin therapy[4]. Although large series have beenreported in other areas of anaesthesiawithout epidural haematoma, reportsfrom cardiac anaesthesia have been insmall populations [5]. The incidencesthat Turfrey and co-workers quote forhaematomas resulting from the use ofepidurals in other areas of anaesthesia,such as obstetrics, are not extrapolatableto cardiac anaesthesia. Far more pro-found levels of anticoagulation are usedfor cardiopulmonary bypass than else-where and this is often compounded bythe development of serious coagulo-pathies. In reality, the incidence ofepidural haematoma is unknown in thesetting of cardiac anaesthesia. What thenwould be an acceptable incidence ofepidural haematoma. Turfey and col-leagues suggest that the risk of epiduralhaematoma is less than 1 in 10 000which would fall into Calman’s verbaldescription of risk as ‘very low’ [6].However, the risk may be in realitylow (1 in 1000 to 1 in 10 000) or, worse,moderate (1 in 100 to 1 in 1000), asthese levels of risk cannot be excludedby their study. Given the devastatingnature of paraplegia, low and moderaterisk of epidural haematoma is unaccept-able unless there is some great benefitto be gained from the technique suchas a reduction in mortality or seriousmorbidity.

Perhaps, it is time for cardiac anaes-thetists to overcome more than fourdecades of reservation regarding theuse of epidural anaesthesia. But if theirlong-held concern is to be overcomethen it will require, as Turfrey and col-leagues suggest, a robustly designed trial.The aim of any such trial must be todetermine whether combining epiduralwith general anesthesia reduces mortal-ity, serious morbidity, i.e. myocardialinfarction or both and, if so, is the riskof epidural haematoma at an acceptablylow level.

R. P. AlstonC. J. SinclairD. H. T. ScottRoyal Infirmary of Edinburgh,Edinburgh EH3 9YW, UK

References1 Clowes GHA, Neville WE, Hopkins

A, Ansola J, Simeone FA. Factorscontributing to success or failure in theuse of a pump-oxygenator forcomplete bypass of the heart and lungs;experimental and clinical. Surgery1954; 36: 557–79.

2 Alston RP. Anaesthesia andcardiopulmonary bypass: an historicalreview. Perfusion 1992; 7: 77–88.

3 Altman DG. Practical Statistics forMedical Research, pp. 440–76. London:Chapman and Hall, 1991.

4 Ruff RL, Dougherty JH.Complications of lumbar puncturefollowed by anti-coagulation. Stroke1981; 12: 879–81.

5 Vandermeulen EP, Van Aken H,Vermylen J. Anticoagulants andspinal-epidural anesthesia. Anesthesiaand Analgesia 1994; 79: 1165–77.

6 Calman KC, Royston GHD. Risklanguage and dialects. British MedicalJournal 1997; 315: 939–42.

A replyThank you for giving us the opportunityto reply to the comments made byDoctors Mallik and Bhaskaran and Doc-tors Alston, Sinclair and Scott.

Doctors Mallik and Bhaskaran askabout our informed consent. We gaininformed consent from all patients in thishospital who undergo any procedure.This involves a description of the typeof anaesthetic and surgery they will bereceiving. It is the hospital’s standardpractice that all studies are presented tothe Ethics Committee to gain approvalbefore data from patients’ medical notesare examined and analysed statisticallyand this was done for our retrospectivestudy.

Drs Alston, Sinclair and Scott worryabout bias in the study in favour of theepidural technique, yet our demo-graphic data clearly showed no differ-ences between the two groups and ourextubation criteria were well defined.We have only presented objective data.

Our ‘natural enthusiasm’ was temperedby the deliberate omission of such sub-jective data as the degree of pain and itsrelief. This did not therefore appear inthe paper and we are unsure as to why itis mentioned.

As Drs Alston, Sinclair and Scottstate, the risk of epidural haematoma inpatients who receive epidural analgesiafor coronary artery bypass graft surgery isunknown, but collective data have nowbeen published on nearly 2000 patientswithout a documented haematoma. Inaddition, spinal and epidural haematomacan occur spontaneously even in patientswho have never received neuraxialblockade or heparinisation [1–5]. Thewell-documented risk of death (4%) andmajor complications such as postopera-tive myocardial infarction and cerebro-vascular accident (4%) following thistype of surgery is high enough that itrequires to be fully explained to patientsbefore they sign a consent form. Webelieve that the risk of epidural haema-toma is much lower than 1% and doesnot require specific informed consent.Thus, put into context, if, for the sake ofargument, the risk of haematoma is 1 in1500 then for each haematoma thatoccurred, 60 patients would die and 60would have a stroke as a direct conse-quence of the surgery. If it is possible todecrease the risk of common postopera-tive complications, with only a minimaladded risk of epidural haematoma, thenwe feel the technique should beinvestigated further.

Doctors Mallik and Bhaskaran statethat they feel the catheter should be sited12–24 h before the onset of surgery.Whilst we accept that some institutionsdo site their catheters earlier than we do,similarly there are other centres that sitetheir catheters immediately prior to sur-gery [6–8]. We do not accept that therisk of bloody tap in the hands ofexperienced operators is in the order of1–11%. Certainly in our experience ofover 300 thoracic epidurals for cardiacsurgery to date the incidence of bloodytap through the needle is 1 in 300. Ourprotocol states that in this situation theoperation, and therefore heparinisation,is deferred as agreed in other studies[9–11]. In the presence of normalclinical history and coagulation studies,

Anaesthesia, 1998, 53, pages 511–517 Correspondence................................................................................................................................................................................................................................................


we believe that any bleeding that mayhave occurred on insertion of the cathe-ter, whether recognised or not, will haveceased prior to heparinisation [10, 12].

There has not yet been a large pros-pective study performed to look speci-fically at the differences between the twotechniques. When examining relativelyrare complications the power of any studyinvolving small numbers is unlikely to bestatistically useful. In addition, the abstractby Fillinger et al. quoted by Drs Mallickand Bhaskaran as evidence against anepidural technique is very misleadingsince it did not measure outcome datadespite the title! Whilst we are familiarwith the papers by Thorelius, Stensethand Moore, we were not able to collectthese data in our epidural patients, as itwas a retrospective study. All other studiessuggest that there may be benefits to begained for patients by using this tech-nique and currently we are performing alarge prospective study to address this lackof information. We are also assessing someof these missing parameters.

The concern over epidural haema-toma has arisen in the literature becauseepidural techniques were developed initi-ally in the obstetric population. In thissituation where pain relief is the majoradvantage of the technique and motherand child have a combined life expec-tancy in the region of 120 years, aconservative approach to avoid evenone case of epidural haematoma is onlyright and is completely endorsed andreinforced by ourselves. Major surgery,however, particularly in the elderly orhigh-risk population, carries significantmorbidity and mortality much of whichmay in fact be diminished by regionalsympathetic blockade [13] and cortisolinhibition, in contrast to the thoughts ofDoctors Mallik and Bhaskaran. A reviewof the literature has, therefore, led us tobelieve that postoperative morbidity maybe reduced by careful use of regionalanaesthetic techniques.

We do not wish to be seen to becomplacent and every possible effort ismade to minimise the progression of anepidural haematoma in our patients,should one develop. This can only beachieved by both the full support ofone’s surgical and nursing colleaguesand careful and meticulous monitoring.

We have strict protocols for neurologicalassessment and until further data arecollected we would not support thepractice without all of these criteriabeing fulfilled.

That having been said, those of ouranaesthetic colleagues who express suchconcern about so rare an event fail toappreciate that conventional analgesiawith opioids carries a significant riskalso, especially in the high-risk andelderly populations. Not one outcomestudy in over 100 in the publishedliterature has demonstrated that narcoticanalgesia is safer than, or associated withless morbidity than, regional anaesthesia[13]. Rather than being condemned as‘regional enthusiasts’, we are keen toproduce objective evidence for or againstthe use of either technique for this formof surgery. We believe we have tackledthis controversy appropriately, namelyan initial thorough literature search fol-lowed by a pilot group of patients and asubsequent large prospective study.

N. B. ScottD. J. TurfreyD. A. A. RayN. P. SutcliffeHCI Medical Centre,Clydebank,Glasgow G81 4HX, UK

References1 Schmidt A, Nolte H. Subdural and

epidural haematomas followingepidural anaesthesia: A literaturereview. Anaesthetist 1992; 41:276–84.

2 Groen RJ, Ponssen H. Thespontaneous spinal epiduralhematoma. A study of the etiology(review). Journal of Neurological Sciences1990; 98: 121–38.

3 Russell NA, Benoit BG. Spinalsubdural hematoma – a review.Surgical Neurology 1983; 20:133–7.

4 Markham JW, Lynge HN, StahlmanGEB. The syndrome of spontaneousspinal epidural haematoma: a reportof three cases. Journal of Neurosurgery1967; 26: 334–42.

5 Nakaya M, Katazoe K, Oharma K,Kosakai Y, Kawashima Y. A casereport of spinal epidural haematoma

complicated after open heart surgery.Journal of the Japanese Association ofThoracic Surgeons 1992; 40: 1764–6.

6 El Baz N, Goldin M. Continuousepidural infusion of morphine forpain relief after cardiac operations.Journal of Thoracic and CardiovascularSurgery 1987; 93: 878–83.

7 Mathews ET, Abrams LD. Intrathecalmorphine in open heart surgery.Lancet 1980; 2(8193): 543.

8 Moore CM, Cross MH, DesboroughJP, Burrin JM, MacDonald IA, HallGM. Hormonal effects of thoracicextradural analgesia for cardiacsurgery. British Journal of Anaesthesia1995; 75: 387–93.

9 Baron HC, Laraja RD, Rossi G,Atkinson D. Continuous epiduralanalgesia in the heparinised vascularsurgical patient: a retrospective reviewof 912 patients. Journal of VascularSurgery 1987; 6: 144–6.

10 Rao TLK, El-Etr AA.Anticoagulation following plannedepidural and subarachnoid catheters:an evaluation of neurologic sequaelae.Anaesthesiology 1981; 55: 618–20.

11 Chaney MA. Intrathecal and epiduralanesthesia and analgesia for cardiacsurgery. Anesthesia & Analgesia 1997;84: 1211–21.

12 Ruff RL, Dougherty JH.Complications of lumbar puncturefollowed by antocoagulation. Stroke1981; 12: 879–81.

13 Scott NB. The effects of pain and itsrelief. In: McClure JH, WildsmithJAW, eds. Conduction Blockade forPostoperative Analgesia. London:Edward Arnold, 1991; 78–110.

A simple approach to dosing inchildren

Anaesthetists who care for children mustfrequently calculate dosages of drugs ona mg.kgÿ1 basis. Such calculations areopen to error resulting in under or overdosage. A way to avoid this type ofcalculation altogether is to employ suit-able dilutions of drugs and administerthem on a ml.kgÿ1 basis.

Rocuronium is a recent example ofa drug whose dose (0.6 mg.kgÿ1) doesnot lend itself to easy calculation [1]. My



approach to this is to dilute 30 mg ofrocuronium (3 ml) to 5 ml with sterilewater and to administer 0.1 ml.kgÿ1

(1 ml per 10 kg). Another example isthe dose of glycopyrrolate (10 mg.kgÿ1)and neostigmine (50 mg.kgÿ1) [2]. HereI dilute the contents of the standardampoule (500 mg glycopyrrolate and2500 mg neostigmine) to 5 ml withwater; again the dose is 0.1 ml.kgÿ1.Morphine is a special case since wemust be concerned with both loadingand maintenance doses: 100 mg.kgÿ1

and 25 mg.kgÿ1.hÿ1 respectively forchildren aged over 6 months [3]. Theloading dose can be achieved by diluting10 mg of morphine to 10 ml with sterilewater and giving 0.1 ml.kgÿ1. Hourlymaintenance doses for children weigh-ing less than 40 kg are prepared bydiscarding all but the initial dose of mor-phine from the syringe and rediluting thisdose to 4 ml. The syringe now containsfour maintenance doses of 1 ml each.

Providing syringes are properlylabelled, the use of these techniquesshould reduce the potential for grosserror in paediatric dosing.

G. MeakinRoyal Manchester Children’sHospital,Pendlebury, Manchester M27 4HA,UK

References1 Hopkinson JM, McCluskey A, Meakin

G. Dose response and effective time tosatisfactory intubation conditions afterrocuronium in children. Anaesthesia1997; 52: 428–32.

2 Meakin G, Sweet PT, Bevan JC,Bevan DR. Neostigmine andedrophonium as antagonists ofpancuronium in children.Anesthesiology 1983; 59: 316–21.

3 Meakin G. Anaesthesia for infants andchildren. In: Healy TEJ, Cohen P, eds.A Practice of Anaesthesia, 6th edn.London: Edward Arnold, 1995;673–89.

Asthma: a plea forcommonsense

The report by Padkin et al. [1] describinghalothane to treat asthma raises impor-

tant points as it is a ‘fringe’ treatment. Atrend has developed in hospitals toundertreat status asthmaticus, reflectingconcern with perceived dangers of thedrugs used, but ignoring the high risksof unrelieved asthma caused by mincingabout with feeble measures.

Take aminophylline: here it has fallensomewhat from favour due to a narrowtherapeutic index, adverse reports andmedicolegal cases. The dangers areoverstated. It is recommended by theBritish Thoracic Society guidelines andin higher dosage by the Oxford Handbookof Critical Care, The Merk’ manual andyet higher dosage by The (Australian)Intensive Care Manual Ed. 3 (with usualcautions). I have used it for 26 yearswith safety and efficacy, in asthma andchronic obstructive airways disease, as6–7 mg.kgÿ1 slow bolus followed, ifnecessary, by infusing 0.5–1.25 mg.kgÿ1.minÿ1. Serum levels are unneces-sary if usage is under 24 h, unless thepatient already takes theopylline; cautionthen dictates using lower doses andmeasuring levels.

Persistence with nebulised broncho-dilators in patients who have probablyalready languished for hours shows apoor understanding of the pathophysiol-ogy. If no improvement occurs in areasonable time, say 15 min, then bron-chospasm and bronchiolar oedema are sobad that no nebulised drugs will enterthese airways to do any good. Intra-venous drugs should be given instead –salbutamol, aminophylline or adrenaline.The authors gave a half-dose of amino-phylline. Unsurprisingly the lack ofbenefit seen corresponded with the lowserum level (36 mmol.lÿ1). If a biggerdose of aminophylline had not helped, Iwould then have given adrenaline 1/10 000 very slowly intravenously at0.5–1 ml.minÿ1, titrating rate againsttachycardia, hypertension, arrhthymias,bronchospasm and SaO2. Naturally 100%humidified oxygen, steroids and rapidintravenous rehydration are prerequisites.

The ‘fringe’ treatments re-reportedrecently, magnesium, ketamine and nowhalothane, do work, but are superfluousunless conventional drugs in maximaldoses fail. Also halothane is incompatiblewith adrenaline; cardiac arrest mayoccur. It is not something every registrar

should try! Intravenous aminophyllineand adrenaline remain established in treat-ing severe asthma. Adrenaline in particu-lar is life-saving and, when nothing elsehas helped, can rescue an exhaustedpatient from the risks and expense ofintubation and ventilation.

R. GoodisonWollongong Hospital,NSW 2500, Australia

Ilioinguinal nerve block fororchidopexy

Findlow et al. (Anaesthesia 1997; 52:1110–3) state that ‘Ilioinguinal nerveblock is free of the side-effects of lowerlimb motor block’. This is not the case.Femoral nerve block has been describedafter ilioinguinal nerve block in childrenin two patients [1, 2] and in a series of 81children having ilioinguinal block, threehad femoral nerve block afterwards [3].In adults this complication is alsodescribed [4]. Undetected femoral nerveblock after ilioinguinal block for herniarepair has led to serious injury [5] whenpatients start mobilising postoperatively.It does not seem to be routine practice totest for femoral nerve block after ilio-inguinal nerve block even though it is arecognised complication with poten-tially serious consequences if undetected.

A. LippNorfolk and Norwich Hospital,Norfolk NR14 8AB, UK

References1 Roy-Shapira A, Armoury R, Ashcraft

K, Holder T, Sharp R. Transientquadriceps paresis following localinguinal block for postoperative paincontrol. Journal of Paediatric Surgery1985; 20: 554–5.

2 Derrick J, Aun C. Transient femoralnerve palsy after ilioinguinal block.Anaesthesia and Intensive Care 1996; 24:115.

3 Shandling B, Steward D. Regionalanalgesia for postoperative pain inpediatric outpatient surgery. Journal ofPediatric Surgery 1980; 15: 477–80.



Footnote: This letter was shown to Dr Padkin andcolleagues who declined the opportunity toreply.

4 Rosario D, Skinner P, Raftery A.Transient femoral nerve palsycomplicating preoperative ilioinguinalnerve blockade for inguinalherniorrhaphy. British Journal of Surgery1994; 81: 897.

Self-administration ofpre-operative analgesicsuppositories

In a recent letter to Anaesthesia (1988;53: 91), Jolliffe suggests that othersmight consider adopting the recentchange in practice of patient self-admin-istration of pre-operative suppositories. Ihave been using this method for just over4 years in all cases where analgesic sup-positories are indicated, with the excep-tion of children, in both the day-caseunit and in-patient wards. From over1000 patients self-administering I havehad two refusals that I can remember,both of whom were women who didnot want a suppository under any cir-cumstances. The usual response whenbroaching the subject is a smile and allare relieved when they understand itsreason and they can give it to them-selves. I do not believe there is muchadditional work for nursing staff and it isquicker for them to supply the supposi-tory, glove and gel and let the patient geton with it. In fact, everybody is happyand the patients are still smiling, pain-free, in recovery.

T. R. CoeTorbay Hospital,Torquay TQ2 7AA, UK

Sevoflurane and adult acuteepiglottitis

The role of sevoflurane in difficult air-way management is already established[1, 2] including its use in a child withacute epiglottitis [3]. We have recentlyused sevoflurane for induction of anaes-thesia to secure the airway in a 35-year-old man with acute epiglottitis. Hepresented with a typical history in thesitting position with mild stridor anddrooling saliva. The gradual deterio-ration of the airway in the 3 h afterpresentation necessitated tracheal intu-bation. He was transferred to the

operating theatre and anaesthesia wasinduced with 3–8% sevoflurane in100% oxygen. As he rapidly becameapnoeic, the inhaled concentration wasreduced (4%) and after gentle manualventilation via the facemask, his tracheawas successfully intubated with an 8-mmtube without any difficulty. Later, he wastransferred to the intensive care unit forfurther management. At direct laryngo-scopy the epiglottis and arytenoids werenoted to be grossly swollen.

Sevoflurane is a more potent respira-tory depressant than halothane [4] andits suitability for use in difficult airwaymanagement has been questioned [5]. Acomparison of induction, however,using a vital capacity breath techniqueversus a tidal breathing technique foundno breath holding in either groupdespite high concentrations of sevoflu-rane [6]. Today’s trainees probably havegreater experience with sevoflurane thanhalothane for inhalational induction ofanaesthesia and they are more likely touse it in potentially difficult situations.Our experience illustrates the need forcaution in the use of sevoflurane whenthe airway is endangered.

T. DonnellyY. M. A. WongB. V. S. MurthyDepartment of Anaesthetics,Royal Liverpool University Hospital,Liverpool L7 8XP, UK

References1 Mostafa SM, Atherton AMJ.

Sevoflurane for difficult trachealintubation. British Journal of Anaesthesia1997; 79: 392–3.

2 Barker I. Is sevoflurane replacinghalothane? British Journal of Anaesthesia1998; 80: 123.

3 Milligan K. Sevoflurane induction andacute epiglottitis. Anaesthesia 1997; 52:810.

4 Davies MW. Sevoflurane: a note ofcaution. Anaesthesia 1996; 51: 1082.

5 Fenlon S, Pearce A. Sevofluraneinduction and difficult airwaymanagement. Anaesthesia 1997; 52:285.

6 Yurino M, Kimura H. A comparisonof vital capacity breath and tidalbreathing techniques for induction ofanaesthesia with high sevofluraneconcentrations in nitrous oxide andoxygen. Anaesthesia 1995; 50: 308–11.

Warning notices above beds

Notices above the beds of patients arewidely employed on general wards asreminders to nursing and other health-care staff of particular considerationswhich apply to that patient (nil bymouth, sips, clear fluids only, namednurse, etc.). While clearly importantfor correct patient care, none of thesigns in common use in our hospitalrelates to events which are potentiallylife threatening.

In the Intensive Care Unit, patients areoften admitted with acute neurologicalconditions, such as Guillain–Barre syn-drome, in whom the administrationof suxamethonium could have fatalresults. As suxamethonium is the musclerelaxant of choice for emergencytracheal intubation, it is easy for medicalstaff to overlook this most serious,



potential complication at the time ofintubation. We therefore employ thewarning notice shown at the bedside ofat-risk patients, as a simple but effectivereminder for all staff. Such warningnotices are not currently available ongeneral wards in this hospital, but as itis occasionally necessary to intubate thetracheas of similar patients prior totransfer to the Intensive Care Unit, it ispossible that it could also usefully beemployed there when patients with acuteneurological conditions are admitted.

Intensive Care Units have variablecasemix and each unit may be able toidentify similar, potentially hazardousinterventions for which warning noticesmay be helpful. In our Intensive CareUnit, we admit many immunosuppressedpatients in whom the administration ofcytomegalovirus (CMV) positive bloodproducts is undesirable. We have con-sidered producing warning notices tocover this and other similar situations.

S. HughesG. SmithQueen Alexandra Hospital,Portsmouth PO6 3LY, UK

Old habits, the circle systemand short procedures

The suitability of the circle system withlow flows is not dependent on the bloodgas solubility coefficient as claimed byNel et al. [1]. What they had demon-strated is that their technique of low-flow anaesthesia is only suitable for

agents with low blood gas solubilitycoefficient. Their end point for drop-ping from high to low flow was an FI/FE

ratio greater than 0.8 and they alsoconsidered the ability to maintain thisratio afterwards on a low flow. Essen-tially they were interested in a techniquewhere the expired concentration – andby implication the brain concentration –is close to that set on the vaporiser dial.By contrast, adopting a low-flow tech-nique which approaches that used inclosed circuit anaesthesia, where theaim is to deposit and maintain a givenmass of agent in the brain, the blood gassolubility of the agent has a minor role toplay; there is no clinically significantdifference between the handling ofenflurane, halothane, isoflurane, sevo-flurane or desflurane. Additionally thereis no need for prolonged high flows withany of the agents; after partial denitro-genation of 30–60 s, low flow or closedcircuit can be commenced immediatelyfor procedures as short as 5 min. For theuse of vaporisers outside the circuit, dialsettings for the commonly used agentsare published, or can be calculated [2].

Low-flow anaesthesia is a foggydomain; it has no underlying physio-logical principal: the choice of fresh gasflow is completely arbitrary. In contrast,the choice of flow for both high flowand closed circuit is determined byphysiological and physical factors; inthe former the requirement to eliminateCO2 and in the latter to match patientgas uptake strictly. I would like to sug-gest that flows are not viewed as a merenumerical continuum from high flow to

closed circuit, but rather as a suspensionbridge, with two towers on solid foun-dations between which is slung the deckof low flow; it is unfortunate that wepersist in trying to construct this bridgeusing only one tower. Closed circuitanaesthesia is a surprisingly simple tech-nique to learn: it holds the promise ofexploding many anaesthetic myths; withthe current levels of gas and vapourmonitoring there never has been a safertime to do so.

C. G. PollockCastle Hill Hospital,Cottingham, East YorkshireHU16 5JQ, UK

References1 Nel MT, Ooi R, Lee DJH, Soni N.

New agents, the circle system andshort procedures. Anaesthesia 1997; 52:364–7.

2 Ernst E, Pearson JD. Principles andpractice of closed circuit anaesthesia.Advances in Anaesthesiology 1987; 4:89–122.

New Year, New Anaesthesia

Congratulations on the new formatwhich places the Contents on the frontcover of the Journal. I look forward toenjoying the improved accessibility.

M. HeathLewisham Hospital,London SE13 6LH, UK



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