Correspondence - Wiley Online Library

Anaesthesia, 2000, 55, pages 590±619 ................................................................................................................................................................................................................................................

Correspondence Anaesthesia for organ donation in the brainstem dead

I warmly applaud your editorial Ànaesthesia for organ donation in the brainstem dead ± Why bother?' (Anaesthesia 2000; 55: 105±6). Many practitioners have felt a deep unease since the Conference of Medical Royal Colleges and their Faculties (UK) in 1976 and 1979 defined brain stem death in the UK. This conference was intended to facilitate beating heart organ donation but only concluded that the state of brain stem death was a state of unsurvivable coma and, quite rightly, stopped short of equating it to death itself. Many anaesthetists clearly have been very uneasy about the transplant lobby's rather rash assumption that organ donors do not require anaesthesia. Many anaesthetists do administer an anaesthetic to these patients, with good reason, as set out in your editorial. The problem the transplant lobby have with giving donors an anaesthetic is the perceived additional difficulty in telling the donor's relatives that the donor is not dead but in an unsurvivable coma. It is time all anaesthetists realised that to not administer an anaesthetic to a donor (who is not by any definition dead) is to commit an act of possibly barbarous dishonesty. Whatever the effect on donor numbers, one cannot condone such action. Our personal belief is that more honesty, and not less, would help to overcome some of the reservations that some doctors share over organ transplantation. One can hope that this would increase rather than decrease organ supply.

J. Wace M. Kai Queen Alexandra Hospital, Portsmouth PO6 3LY, UK Young and Matta (Anaesthesia 2000; 55: 105±6) do well to remind us of the alarming haemodynamic responses to the pain of surgery during organ retrieval operations. It is convenient to dismiss these as spinal reflexes, yet spinal reflexes of this immediacy have never been demonstrated in experimental animals. Even if they were to be demonstrated, Occam's Razor would still dictate that these responses are mediated by the brain stem until proven otherwise. The only safe and reasonable conclusion to draw from this is that the current UK brainstem death criteria do not suffice to demonstrate that the entire brain stem is invariably dead. The ethical question we have to ask ourselves therefore is this: would we be content to cremate the body of a loved one in the knowledge that it would withdraw its limbs and that there would be a sharp rise in heart rate and blood pressure when it entered the furnace? If we would not, then we have no right to inflict a similar fate on an un-anaesthetised organ donor. Recent events have shown just how squeamish the public is when it hears about organs being removed many hours after circulation has ceased. What sort of reaction do you imagine we would get if we told them honestly about these responses in beating-heart organ donors? Many of us have been pressing for years for a complete reappraisal of the UK brainstem death

criteria. Until that happens, anaesthetising organ donors is probably the best pragmatic fudge available to us. P. J. Keep Norfolk and Norwich Hospital, Norwich NRI5 2YR, UK Chemoprophylaxis for meningococcal disease in healthcare workers

Since the successful implementation of Hib vaccine in 1994, Neisseri meningitidis has become the leading infectious cause of death in childhood in the UK. More than 2000 cases of meningococcal disease are reported each year, with a mortality rate of about 10%, rising to 50% in severe cases. In 1999, 104 cases of meningococcal disease were admitted to our paediatric intensive care unit (PICU), of which 100 (98%) were retrieved from various referral hospitals in the region. As part of the retrieval team for the PICU, we are frequently asked for guidance regarding self-prophylaxis by the referring healthcare workers, especially from anaesthetists who have had close involvement with the resuscitation of the patient. In our series, anaesthetists at the referring hospitals performed airway management manoeuvres in 85% of cases, some with frank pulmonary oedema, and therefore potentially exposed to nasopharyngeal secretion and sputum. There is controversy regarding this issue as there is little scientific data on which to assess risk. Nasopharyngeal carriage of meningococci is common (up to 10% of the population may carry a number of meningococcal strains). The disease is spread via droplet transmission

All correspondence should be addressed to Professor M. Harmer, Editor of Anaesthesia, Department of Anaesthetics, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, 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 usual style and format of the Correspondence section. Authors must follow the advice about references and other matters contained in the Notice to Contributors to Anaesthesia printed at the back of each issue. The degree and diplomas of each author must be given in a covering letter personally signed by 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 the letter comments on a published article in Anaesthesia, please send three copies; otherwise two copies of your letter will suffice.

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q 2000 Blackwell Science Ltd

Anaesthesia, 2000, 55, pages 590±619 Correspondence ................................................................................................................................................................................................................................................

through close contact and viable organisms may be found in the nasopharynx of presenting cases even after community administration of penicillin. Only a few cases arise from contact, and a quoted figure of 0.5% of all cases are associated with family contact. There has been one reported case of a French paediatrician contracting severe meningococcal infection one week after having intubated a comatose patient with meningococcal disease. Prophylaxis for healthcare workers has recently been reviewed by Pollard [1], who suggested that the offer of antibiotic prophylaxis should be extended to all healthcare workers who have had direct exposure to nasopharyngeal secretions from a patient with meningococcal infection. This is to reduce colonisation of recipients and their close contacts with virulent strains. This advice concurs with that given in the United States, but goes against UK guidelines, which stipulate that chemoprophylaxis (rifampicin, ciprofloxacin or ceftriaxone) should only be given to those who administered mouth-tomouth resuscitation to patients with meningococcal disease [2]. Pollard's advice raised concerns in the microbiological community that widespread chemoprophylaxis would have implications regarding the abolition of the recipient's own protective nasopharyngeal flora, leading to the acquisition of pathogenic flora. There were also concerns regarding the emergence of resistance to rifampicin as well as to ciprofloxacin, and its financial implications [3±6]. The issue of vaccination is also contentious. A protein±polysaccharide conjugate vaccine against group C meningococcal disease has recently been introduced in the immunisation schedule in the UK and is expected to decrease cases due to this serogroup. However, there is no effective vaccine for the meningococcus B serogroup, which causes approximately 40% of serious infections, and likely to increase following the introduction of the serogroup C vaccine. Thus, vaccination would not remove the perceived need for chemoprophylaxis. More elementary to the above


discussion is the role of preventative measures during the early management of meningococcal cases. Barrier protection in the form of masks and perhaps goggles should be worn when intubating children presenting with the features of meningococcal disease, who have not had 24 h of antibiotic therapy. These basic precautions significantly reduce the risk of disease transmission during resuscitation. In view of this controversy, what is the best practice? Chemoprophylaxis for health workers involved in airway manoeuvres in patients who have frank pulmonary oedema seems logical but is not evidence based. Consultants in communicable disease control have a difficult task of allaying the anxiety of the exposed personnel whilst assessing the risk of disease transmission in each individual case. Clearly there is a need for a review of current UK guidelines and for distribution of information regarding the risk to healthcare workers in these circumstances. Until then, ignorance of the estimated risk will result in controversy and cases such as that of the French paediatrician will continue to alarm those exposed to the disease. A. Cooney N. Mehta St Mary's Hospital, London W2 1NY, UK References 1 Pollard AJ, Begg N. Meningococcal disease and healthcare workers. British Medical Journal 1999; 319: 1147±8. 2 Anon. Control of meningococcal disease: guidance for Consultants in communicable disease control. PHLS Meningococcal Infections Working Group and Public health Medicine Environmental Group. Communicable Disease Report 1995; 5:R: 189±95. 3 Flood TJ. Use of antibiotics to prevent Meningococcal infection in Healthcare Workers. e-Letter. E-British Medical Journal 1999; 12 November. 4 Wilcox MH, Modi N. Management of meningococcal sepsis and risk of infection in healthcare workers. e-Letter.

E-British Medical Journal 1999; 10 November. 5 Gilmore A, et al. Meningococcal Disease in healthcare workers: developing appropriate guidelines. eLetter. E-British Medical Journal 1999; 18 November. 6 Cowling D. Meningococcal prophylaxis. e-Letter. E-British Medical Journal 1999; 20 November. Incidence of blood-borne infectious micro-organisms: would you still not wear gloves?

Several surveys have shown that anaesthetists often do not care for precautions for preventing transmission of bloodborne infectious agents [1±4]. For example, still a high proportion of anaesthetists do not wear gloves routinely during anaesthetic practice [1±4]. The proportion of anaesthetists wearing gloves increases when they know that the patient has a blood-borne virus [1, 2], but screening for viruses is not done in many hospitals, and thus its incidence in patients undergoing surgery is not known. At our hospital in Japan, routine screening is done and a record is kept for blood-borne infectious viruses in all patients who are scheduled for elective surgery under either general or regional anaesthesia. In 6437 patients who underwent surgery during the last 2 years, at least one infectious virus was detected in 534 patients (8.3%) (Table 1). In addition, infection of methicillin-resistant Staphylococcus aureus (MRSA) was reported in 166 patients (2.6%). Although these figures may differ from other regions, the results indicate that anaesthetists may frequently contact with infectious microorganisms. If one gives anaesthesia for 5±10 patients a day, one may encounter patients with infectious viruses almost every day. Isn't it time to change our attitude and start wearing gloves routinely and washing hands between each case? T. Asai S. Matsumoto K. Shingu

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Correspondence Anaesthesia, 2000, 55, pages 590±619 ................................................................................................................................................................................................................................................

Table 1 The number and incidence of blood-borne infectious viruses in patients

undergoing elective surgery under either general or regional anaesthesia (n 6437)

Hepatitis B virus (HBV) Hepatitis C virus (HCV) Human immunodeficiency virus (HIV) At least one of above positive

Kansai Medical University, Moriguchi City, Osaka, 570±8507, Japan References 1 O'Donnell NG, Asbury AJ. The occupational hazard of human immunodeficiency virus and hepatitis B virus infection. I. Perceived risks and preventative measures adopted by anaesthetists: a postal survey. Anaesthesia 1992; 47: 923±8. 2 McNamara JT, Stacey SG. Poor anaesthetist hygienic practice ± a problem across all grades of anaesthetist. Anaesthesia 1999; 54: 718±19. 3 El Mikatti N, Dillon P, Healy TEJ. Hygienic practices of consultant anaesthetists: a survey in the NorthWest region of the UK. Anaesthesia 1999; 54: 1±3. 4 Harrison CA, Rogers DW, Rosen M. Blood contamination of anaesthetic and related staff. Anaesthesia 1990; 45: 831± 3.

Alzheimer's disease and anaesthesia

There is an increasing awareness that head injury resulting in loss of consciousness is associated with an increased risk of Alzheimer's disease [1]. Recent studies indicate that deposition of amyloid beta occurs in approximately one third of individuals who die after severe head injury [2]. Apolipo protein E (ApoE) is a transport system prominent in response to injury prompting the need to better understand the relationship between acute brain injury and the development of neurodegeneration such as Alzheimer's disease [3]. All attention to date has focused on head injury, whilst other comparable hypoxic

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140 407 1 534

(2.2%) (6.3%) (0.0001%) (8.3%)

ischaemic brain insults have not been evaluated to see whether or not they may prove to be an epidemiological risk factor for the development, or possibly influence progression of this group of neurological diseases. Alzheimer's disease is the commonest cause of dementia overall, accounting for more than 50% of all cases, with an exponential increase in incidence with advancing age. Such patients, either before clinical signs or in early symptomatic disease, may well require to undergo general anaesthesia. There is to date no study addressing whether anaesthesia is associated with thereafter the presentation or worsening of Alzheimer's disease. We report a case in which deterioration after anaesthesia was evident and speculate on the need for observational studies, possibly combined with ApoE genotyping to ensure that our observation does not have wider more generalised implications. We recently reviewed a case in which a patient with Alzheimer's disease deteriorated after an anaesthetic. The literature is silent on any interaction. This patient, a man aged 67 years, was scheduled to have bilateral varicose veins. He was obese (108 kg; 1.5 m height). He had intermittent hypertension (200/95; 190/110) but was not being treated. His pre-operative blood pressure was 160/90. He had longstanding right bundle branch block. His ECG showed no evidence of left ventricular hypertrophy. His peak expiratory flow rate was normal. He had suffered bouts of weepiness, feeling depressed and difficulty in sleeping and was having a selective serotonin reuptake inhibitor (Lustralw ± sertraline hydrochloride). On admission, his wife reported that he was forgetful and confused, and might start weeping if he did not know where she was.

Twenty years before he had had varicose veins operated upon. He reported that he was awake during the surgery. That record was not available. In the 8 years before this operation he had three genito-urinary operations, a prostatectomy, cystoscopy and internal urethrotomy, without any complications. On this occasion recorded `routine monitoring' was recorded, but there were no records of oxygen saturations although there were of blood pressure. The blood pressure varied between 115/75 and 95/55. These were lower than the lowest figures of any of the other previous anaesthetics. The operation took 90 min. He had propofol 200 mg, nitrous oxide, halothane and alfentanil 1 mg. He breathed spontaneously through a laryngeal mask airway. He was in the prone position for some of the period. The operation was difficult. On return to the ward, he was restless and nauseous. He received cyclimorphw (morphine 10 mg, cyclizine 39.01 mg). He was confused postoperatively and retained in hospital for 3 days. On the third day he went home and at midnight got up, removed the bandages and accused his wife of `cutting him'. His general practitioner was called at 3.00 a.m. and administered sedation. He improved slowly and by 6 weeks was well enough to go on holiday. After 5 months he was referred to a psychogeriatrician who recorded that he had episodes of confusion, forgetfulness and got lost when he went out. He was sleeping a lot and was incontinent during the day. One year later he had an uneventful cystoscopy. That anaesthetic consisted of propofol, fentanyl, nitrous oxide and isoflurane. His blood pressure ranged from 140/80 to 130/70. Two years later he required residential care, having deteriorated substantially. It would seem that his postoperative confusion and the accentuation of his symptoms were related to a relatively hypotensive, prolonged anaesthetic. This might have been avoided by proper preoperative evaluation, including consideration of his previous anaesthetics without complications. Whether the incident contributed to the progress of



his Alzheimer's disease is problematic. It would be valuable to hear of any other accounts of anaesthesia in patients who subsequently were found to have developed Alzheimer's disease, as if confirmed, this could well lead to an important case-controlled study. I. Bone Southern General Hospital, Glasgow G51 4TF, UK M. Rosen 45 Hollybush Rd, Cardiff CF23 6TZ, UK References 1 O'Meara EA, Kikull WA, Sheppard L, et al. Head injury and the risk of Alzheimer's disease by Apolipo protein E genotype. American Journal of Epidemiology 1997; 146: 373±84. 2 Nicholl JA, Roberts GW, Graham DI. Amyloid beta protein, APOE genotype and head injury. Annals of the New York Academy of Sciences 1996; 777: 271±5. 3 Graham DI, Horburgh K, Nicholl JA, Teasdale GM. Apolipoprotein E and the response of the brain to injury. Acta Neurochirurgica ± Supplementum 1999; 73: 89±92.

Forgotten already?

Our good friend Tom Boulton, a past president of both the Association of Dental Anaesthetists and the Society for the Advancement of Anaesthesia in Dentistry as well as the Association of Anaesthetists of Great Britain and Ireland, omits one word in his excellent Editorial (Anaesthesia 1999; 54: 823±5) ± dentists. We refer in particular to the phrase `that the administration of anaesthesia in the British sphere of influence has had the advantage of remaining exclusively in the hands of medically qualified practitioners.' Perhaps in reflecting on the history of anaesthesia we might also consider the part played by dentists. The earliest use of general anaesthesia was for dental procedures. Horace Wells was a dentist as were Morton and Robinson, the last being credited with


the first use of general anaesthesia in the UK. In Britain more general anaesthetics were given for dentistry than for any other procedure: in the last 50 years more than 20 million, and most of these were administered by dentists. It has been fashionable in recent years to deride this contribution and service by our profession but the fact remains that millions of patients benefited from it. One must also remember that the safety record of chair-side anaesthesia was not related to the class of administrator be they general dental practitioner, general medical practitioner or specialist anaesthetist. At the close of the 20th century we dentists voluntarily passed this service to the speciality of anaesthesia [1]. Dentists should not only look back proudly on their contribution to general anaesthesia and the enormous service they have provided their patients over the last century and a half but they should also be remembered for it. I. Brett A. Wraith Society for the Advancement of Anaesthesia in Dentistry, London W1M 7DF, UK Reference 1 General Dental Council. Maintaining Standards. Guidance to Dentists on Professional and Personal Conduct. London: General Dental Council, 1998.

A reply

I regret now that I did not add the words ànd of dental surgeons in their own practices' to the phrase which Ian Brett and Andrea Wraith quote from my Editorial in the September 1999 issue of Anaesthesia (1999; 54 : 823±5). I consider, however, that the context of the phrase in my Editorial implied that I was referring to the administration of anaesthesia for surgery in general. The employment of dental surgeons as anaesthetists for surgical procedures other than outpatient dentistry has been extremely rare in British practice, even under the exigencies of war.

Discussion about priorities in the history of anaesthesia is, of course, of great interest, and many authors have considered the matter exhaustively [1± 4]. My Editorial was not about the history of anaesthesia per se however; it was concerned with the development of the major medical anaesthetic organisations in the United Kingdom [5]. The medical practitioner John Snow was mentioned in the Editorial because ìt was certainly due to the appreciation by his contemporaries of Snow's superior skill, based on scientific investigation, that the administration of anaesthesia in the British sphere of influence has had the advantage of remaining exclusively in the hands of medically qualified practitioners' and [I accept] dental surgeons in there own practices [6, 7]. This fact formed the basis for the later development of the medicopolitical organisation of anaesthesia in the United Kingdom [5]. The dentists Wells and Morton gave up the administration of anaesthesia soon after their important initial demonstrations of nitrous oxide and ether anaesthesia and became involved in an unedifying struggle to establish priority [1±3]. Robinson, arguably the leading dentist in England in the 1840s, ceased to administer anaesthetics shortly after publishing the first textbook on ether anaesthesia in 1847. This was because he had other major projects in dentistry to pursue [7]. John Snow continued to study anaesthesia and anaesthetised patients for a variety of surgical procedures from the time of the introduction of ether anaesthesia in 1846 until his death in 1858 [6±8]. I expended a great deal of effort during my active career in an endeavour to reconcile the views of the medical and dental professions regarding who should administer anaesthesia for outpatients, as well as how, why and when they should do so. Extremists of both professions have sometimes made immoderate or prejudiced assertions. I have recently tried to present fairly and chronologically the various issues that have arisen during the last three-quarters of a century [5]. The standards of practice justifiably accepted in the middle of the 20th century are obviously not those that are acceptable in the 21st century however. Time has moved on.

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The admirable record of dental surgeons who devoted time and effort to improving both expertise and safety in the practice of outpatient anaesthesia in their own practices should certainly not be forgotten. Dental surgeons have also made major contributions to the development of sedation techniques in recent decades [5]. I predicted in 1980, in my Presidential Address to the Society for the Advancement of Anaesthesia in Dentistry (SAAD), that `full general anaesthesia `ìn the chair'' will give way to psychological and pharmacological techniques of analgesia and sedation short of full general anaesthesia' [9]. This suggestion was unpopular with some of my audience at the time, but I consider that it has proved to be justified. T. B. Boulton Honorary Consultant Anaesthetist, Oxford & Reading Hospitals, UK References 1 Duncum BM. The Development of Inhalation Anaesthesia. London: Oxford University Press, 1947. 2 Boulton TB, Wilkinson DJ. The origins of modern anaesthesia. In: Healy TJ, Cohen PJ, eds. Wylie and Churchill Davidson's a Practice of Anaesthesia. London: Edward Arnold, 1995: 3±35. 3 Rushman GB, Davies NJH, Atkinson RS. A Short History of Anaesthesia. Oxford: Butterworth-Heinemann, 1996. 4 Bergman NA. The Genesis of Surgical Anaesthesia. Park Ridge: Wood LibraryMuseum of Anesthesiology, 1998. 5 Boulton TB. The Association of Anaesthetists of Great Britain and Ireland and the Development of the Specialty of Anaesthesia, 1932±92. London: Association of Anaesthetists of Great Britain and Ireland, 1989. 6 Ellis RH, ed. The Case Books of John Snow. Medical History Supplement 14. London: Wellcome Institute for the History of Medicine, 1994. 7 Ellis RH, ed. James Robinson on the Inhalation of the Vapour of Ether. Eastbourne: Boiler Tindall, 1983.

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8 Snow J. Chloroform and Other Anaesthetics. London: Churchill, 1858. 9 Boulton TB. Presidential address: The rise and fall of general anaesthesia in the dental chair. SAAD Digest 1980; 4: 156±65.

The anaesthetic team

I read with great interest Dr Morgan's Editorial (Anaesthesia 2000; 55: 1±3) concerning his examination of anaesthesia development, and would like to take up two points. Firstly, what does Dr Morgan mean by the phrase ± `We have been fortunate in this country in that anaesthesia has been a physician-only speciality'? Fortunate for whom? The patient or the doctor? I presume that Dr Morgan is making a reference to the issue of the nonphysician anaesthetist that is common with our North American and European colleagues. This issue has been debated for a number of years in the UK, and there has been recent agreement by Medical and Nursing organisations that this would do little to solve the anaesthetic manpower crisis or help develop the provision of anaesthesia in the NHS [1±2]. One hopes that this issue is now finally laid to rest. However, there are valuable lessons that can be learnt from the US and European approach to anaesthesia, specifically in the development of the anaesthetic team. It is not uncommon in the US for a team of an Anaesthesiologist, Nurse Anaesthetist and Assistant to utilise a case management approach for the peri-anaesthetic period. A hybrid of this model transferred into the UK context could improve patient care, and develop and foster collaborative working practices with greater professional understanding. If in the UK an anaesthetist, anaesthetic nurse and recovery nurse were to jointly consider the plan of care for a patient undergoing surgery it would go a long way to providing a total peri-anaesthetic care package. The added benefits of this would reduce risks associated with communication errors, and provide seamless continuity from admission to discharge. My second point is one of addition to

Dr Morgan's historical review. One can only concur with the sentiments that the technological advancement in anaesthesia has indeed reduced morbidity and mortality considerably. This has led to the position today where it is thankfully rare for unexpected intra-operative complications to occur. However, despite these changes the postoperative period still frequently presents challenges to the medical and nursing staff. Indeed, the importance of effective and skilled recovery was highlighted within the first two decades of `modern anaesthesia' in 1846. From Flemings' original idea in 1923 at the Medical Institute of Birmingham, the concept of an integral recovery unit has been reinforced continually since [3]. It has been suggested that it is the development of recovery units that have proven most effective in reducing deaths from anaesthesia in the last 150 years [4]. I believe that the RCA use the availability of the post anaesthetic recovery units as a benchmark for accessing a hospital's suitability for training of junior anaesthetists. M. Radford Vice Chairman & Editor, British Anaesthetic & Recovery Nurses Association, Sutton Coldfield B76 1RQ, UK References 1 Reilly C, Challands A, Barrett A, Reid S. Professional Roles in Anaesthesia: a Scoping Study. Leeds: NHS Executive, 1996. 2 Radford M. Nurse anaesthetists: a job too far? British Journal of Nursing 1999; 8: 14. 3 Anon. Report: National Confidential Enquiry into Perioperative Deaths. London: 1990. 4 Carrie L, Simpson P, Popat M. Understanding Anaesthesia, 3rd edn. London: Butterworth Heinemann, 1996.

Postoperative nausea and vomiting following 8% sevoflurane anaesthesia

We read with interest recent correspondence concerning postoperative nausea



and vomiting (PONV) following 8% sevoflurane anaesthesia (Anaesthesia 2000; 55: 189±91). Various explanations were proposed for the observed increase in PONV including the administration of supplemental opioids, and/ or a dose-related sevoflurane effect. There is little evidence, if any, to support the latter. In their paper, Dashfield and colleagues use high concentrations of sevoflurane yet report an extremely low incidence of nausea (10%) [1]. It is important to note that Dashfield and colleagues used a nonrebreathing system in their study and thus did not expose the sevoflurane to soda lime. Conversely, Smith and Thwaites used low-flow anaesthesia with CO2 absorption and reported an incidence of 30% [2]. In a study similar to that of Dashfield and co-workers, Philip reports that following sevoflurane induction and maintenance, 78% of patients experienced some nausea. This study maintained anaesthesia using sevoflurane at low fresh gas flows (2 l.min21). No opioids were administered [3]. Fredman and coworkers also report an extremely high incidence of nausea (56%) following a lower dose of sevoflurane for induction of anaesthesia and maintenance of anaesthesia using low fresh gas flows [4]. We propose an additional cause of PONV following sevoflurane anaesthesia. It is known that sevoflurane can be degraded to formaldehyde when passed through partially exhausted soda lime [5]. Rather than the absolute dose of sevoflurane delivered, an additional factor in PONV may be the administration of sevoflurane through a rebreathing system that contains a strong alkali. Inhalation of formaldehyde, even in minute quantities, will provoke significant nausea and vomiting often for up to 48 h [6]. We believe that when examining the occurrence of nausea following sevoflurane anaesthesia, it is of fundamental importance to know whether or not sevoflurane has been delivered using a rebreathing system. Our own work (in progress) shows that formaldehyde concentrations of four times the MEL (maximum exposure limit) are readily achieved in vitro by


simply passing 6±8% sevoflurane over dry soda lime. As a result, we would suggest that degradation of sevoflurane to formaldehyde by CO2 absorbents that contain either KOH or NaOH be considered as an additional factor contributing to PONV after sevoflurane anaesthesia. A. Bedi A. Gallagher J. P. H. Fee J. M. Murray The Queen's University of Belfast, Belfast BT9 7BL, UK References 1 Dashfield AK, Birt DJ, Thurlow J, Kestin IG, Langton JA. Recovery characteristics using single-breath 8% sevoflurane or propofol for induction of anaesthesia in day-case arthroscopy patients. Anaesthesia 1998; 53: 1062±6. 2 Smith I, Thwaites AJ. Target-controlled propofol vs. sevoflurane: a doubleblind, randomised comparison in daycase anaesthesia. Anaesthesia 1999; 54: 745±52. 3 Philip BK, Lombard LL, Roaf ER, Drager LR, Calalang I, Philip JH. Comparison of vital capacity induction with sevoflurane to intravenous induction with propofol for adult ambulatory anesthesia. Anesthesia and Analgesia 1999; 89: 623. 4 Fredman B, Nathanson MH, Smith I, Wang J, Klein K, White PF. Sevoflurane for outpatient anesthesia: a comparison with propofol. Anesthesia and Analgesia 1995; 81: 823±8. 5 Funk W, Gruber M, Wild K, Hobbhahn J. Dry soda lime markedly degrades sevoflurane during simulated inhalational induction. British Journal of Anaesthesia 1999; 82: 193±8. 6 United States Environmental Protection Agency-Formaldehyde. http://www.epa.gov/iedweb00/ formalde.html.

Unexpected difficult intubation caused by subglottic ring

We wish to report a case of unexpected

difficult intubation after induction of anaesthesia caused by a tracheal ring. A 58-year-old woman, ASA III, was admitted for hysterectomy and bilateral salpingo-oophorectomy because of endometrial adenocarcinoma. Medical history revealed morbid obesity, noninsulin-dependent diabetes mellitus, hypertension and chronic asthmatic bronchitis treated with b2-adrenergic agonists, methylxanthines and oxygen therapy. Pulmonary function testing revealed an FEV1 of 38%, arterial blood gases confirmed hypoxaemia (Pao2 51 mmHg) and slight hypercapnia (Paco2 43 mmHg). Past surgical history included a laparotomy under general anaesthesia requiring some days in ICU because of her morbid obesity. Difficulty of tracheal intubation was suspected because of obesity and inadequate neck extension; after topical anaesthesia, vocal cords were clearly seen at laryngoscopy. General anaesthesia was induced and vecuronium 12 mg was given to facilitate tracheal intubation. A 7.5-mm i.d. tracheal tube could not be advanced beyond the vocal cords because of resistance. Intubation was reattempted with smaller tubes; finally, a 5.0-mm i.d. tube was passed through the vocal cords but adequate ventilation could not be maintained. The patient's trachea was extubated and normal emergence from anaesthesia occurred. Because of the unexpected difficulties in intubation an otolaryngologist was consulted in the operating theatre to examine the larynx and trachea. A tracheal ring was found which caused subglottic stenosis. Because of morbid obesity the patient was observed overnight in ICU. In the following days, following tracheostomy under local anaesthesia, general anaesthesia was induced and laser airway surgery was performed. Her tracheostomy was maintained to allow a hysterectomy and bilateral salpingo-oophorectomy to be carried out. Some weeks later the tracheostomy tube was removed, her flow volume loop improved and oxygen therapy was discontinued. Our case of difficult intubation was unexpected even though a difficult

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laryngoscopy was anticipated for morbid obesity and inadequate neck extension; after induction of general anaesthesia, a tracheal ring created an obstacle to tracheal intubation and only a very small tracheal tube could be passed (5.0-mm i.d. tube), which proved inadequate for ventilation. A tracheal ring consists of a congenital or acquired, fibrous membrane. An acquired ring may develop as a result of injury to the tracheal mucous membrane and submucosal tissues primarily due to iatrogenic intervention, especially longterm intubation [1±3]. Postoperative review of the patient's history revealed worsening of dyspnoea following her previous laparotomy. Her postoperative period of ventilation in ICU for morbid obesity probably caused scaring, which resulted in an acquired tracheal ring. However, her increasing tracheal stenosis was confused with worsening of chronic bronchitis. In this case a tracheal ring was an unsuspected and coincidental finding but caused an obstacle to tracheal intubation [1±3]. The absence of symptoms such as stridor or sign of upper airways obstruction, in spite of a marked decrease in tracheal cross-section, is consistent with the observation that symptoms rarely occur until at least 75% of the tracheal diameter has been obliterated [3]; in this case exertional dyspnoea was attributed to worsening of chronic bronchitis.

caused by a laryngeal web. British Journal of Anaesthesia 1997; 79: 396±7. 3 Baron SH, Kohlmoos HW. Laryngeal sequelae of endotracheal intubation. Anesthesia and Analgesia 1975; 54: 767± 72.

Airway Management Device (AMDTM) for airway control in percutaneous dilatational tracheostomy

Since the first description of the technique in 1985 [1], percutaneous dilatational tracheostomy has developed into a bedside procedure on the Intensive Care Unit. Experience has shown that airway control in the intubated patient during tracheostomy has been fraught with difficulties. These include accidental extubation, transfixion of the tracheal tube by the introducing needle and cannula, and deflation of the cuff from inadvertent puncture by the needle [2]. Needle damage to flexible bronchoscopes used for tracheal visualisation of

the procedure can also occur. We describe the use of a new airway adjunct, which may overcome these problems. The Airway Management Device (AMDe) (Biosil Ltd, Cumbernauld, UK) is a hollow, clear, silicone rubber tube with two inflatable cuffs along its length (Fig. 1). The tapered distal cuff sits at the end of the tube and, when inflated with 6±10 ml of air, occludes a small central lumen. When the AMD is inserted with the distal cuff inflated it lodges into the upper oesophagus. Deflation of the cuff after placement allows passage of a suction catheter into the oesophagus to clear secretions. The proximal cuff sits at the level of the pharynx and is inflated with a variable volume of air such as to occlude the pharynx and prevent gas leakage during ventilation. Between the two cuffs is a short length of exposed tube with an anterior-facing elliptical hole, and when the AMD is correctly sited this hole faces onto the laryngeal inlet. Ventilation is via the integral 15-mm rightangled swivel-mount on the top of the

A. Ceron V. Ambroselli C. Zannoni Circolo Hospital, Varese, Italy D. Bertollo via Matteotti 9, 21045 Gazzada (VA), Italy References 1 Capistrano-Baruh E, Wenig B, Steinberg L, Stegnjajjc A, Baruh S. Laryngeal web: a cause of difficult endotracheal intubation. Anesthesiology 1982; 57: 123±5. 2 Chong Z-K, Jawan B, Poon Y-Y, Lee JH. Unsuspected difficult intubation

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Figure 1



tube. Suction catheters can be inserted via the silicon stopper on top of the mount. The AMD was used during tracheostomy in an 83-year-old male ventilated on our Intensive Care Unit. He was recovering from emergency repair of ruptured abdominal aortic aneurysm, compounded by haemodynamic instability from poor myocardial function. The decision to perform tracheostomy was made on day 5 to facilitate anticipated longer-term ventilation and weaning. Following paralysis and increased sedation, the patient had his 9.0 oral tracheal tube removed and a size 3±3.5 AMD inserted with 8 ml air in the lower cuff. A volume of 50 ml air was used to inflate the upper cuff and ventilation continued with 100% O2. Gas leakage occurred around the upper cuff and a further 10 ml of air was introduced with some reduction in leak. Inflation of the lungs was satisfactory and the patient was positioned with extended neck prior to tracheostomy. No increase in leak occurred but it was noted that the tongue was becoming congested. We had previously noted this phenomenon during use of the AMD in general anaesthesia. It was not improved by adjusting the position of the AMD. Our Intensive Care Unit's normal practice is to perform percutaneous tracheostomy under bronchoscopic control, and so an Olympus 5.2-mm flexible bronchoscope was inserted through the swivel-mount, which maintained a gas-tight seal, and was passed in to the upper trachea with some difficulty. This was because the epiglottis had been pushed down on to the orifice of the AMD and the glottic opening was deviated to the right. Percutaneous dilatational tracheostomy using the Ciaglia kit (Cook Critical Care) was performed in the usual manner and an 8.0 Tracheosoft PERCe (Mallinckrodt Medical) tracheostomy tube with adjustable flange inserted. Correct placement and adjustment of the tube was made using the flexible bronchoscope, and mechanical ventilation recommenced. At the end of the procedure it was noted that the tongue was much more congested, enlarged and had a bluish colour. This


quickly resolved on deflation and removal of the AMD. No oropharyngeal trauma was noted and no regurgitation or aspiration of gastric contents was seen. The whole procedure took 30 min. Use of the AMD facilitated percutaneous tracheostomy in this patient, but was not without its problems. Repositioning could not reduce glottic congestion and, although it quickly resolved on AMD removal, we do voice concerns over possible lingual nerve damage with prolonged use, similar to that which has been described with use of the laryngeal mask airway [3]. Use of the larger size AMD, size 4± 5, may have overcome this problem. We feel that the AMD may have a useful role in airway management during percutaneous tracheostomy, particularly as it overcomes the problems with having a tracheal tube in situ, and we are undertaking a further study to assess its clinical potential in the critical care setting. R. Johnson R. Bailie Royal Halifax Infirmary, Halifax HX1 2YP, UK References 1 Ciagla P, Firsching R, Syniec C. Elective percutaneous dilatational tracheostomy: a new simple bedside procedure: preliminary report. Chest 1985; 87: 715±9. 2 Thomas EO, Manara AR. A review of percutaneous tracheostomy. British Journal of Intensive Care 1998; 8: 122±9. 3 Majumder S, Hopkins PM. Bilateral lingual nerve injury following the use of the laryngeal mask airway. Anaesthesia 1998; 53: 184±6.

Complications following the use of the Combitube, tracheal tube and laryngeal mask airway

We wish to comment on the article by Oczenski et al. (Anaesthesia 1999; 54: 1161±5) describing a higher rate of complications with the use of the Combitube 37 F SA (CT) than with the other two devices.

The authors describe that in the CT group of 25 patients the device was electively inserted with difficulty in 13 patients (52%), two patients required two attempts and one patient required three attempts. With this grade of difficulty, they reported an incidence of 48% sore throat, of 68% dysphagia, which were severe and long lasting (. 24 h) in eight patients (32%), and the presence of haematoma in 36%. These findings are opposite to our results in 25 patients using the same model of CT inserted under direct laryngoscopy [1], in which no severe complication could be observed. Oczenski's results are also opposite to the low rate of complications reported in the literature using the larger size 41 F, inserted by technicians and in emergency prehospital situations [2, 3]. We were surprised that the four experienced participant anaesthetists obtained such a high rate of complications in performing an elective procedure, including the occurrence of haematoma in 4% of both the LMA and the ET group and an 8% failure rate in the insertion of the LMA, which also contrasts with the published experience [4]. We think that this high rate of complications suggests that the procedures were traumatic, probably due to an inappropriate insertion technique or insufficient operator skill. Although the CT design allows blind insertion, the manufacturer [5] recommends using a laryngoscope in order to avoid complications derived from a blind procedure. On the other hand, 60% nitrous oxide could over-inflate the cuffs over time, which may induce mucosal injury [6, 7]. Thus, we think that the reason given by the authors to explain the higher incidence of postoperative complications could be overestimated by this factor. In addition, we consider that the conclusion that the CT cannot be recommended for routine airway management is not acceptable. Such a conclusion, with regard to safety, cannot be stated from data on only 25 patients. Finally, since the CT is a device often used in the emergency airway management, its use for routine airway management is advisable, especially in residency programmes [8]. With routine

597


use the operator will gain experience and will avoid seeing it for the first time during efforts to ventilate a `failed intubation'. R. M. Urtubia C. R. CaÂrcamo J. M. Montes Mutual de Seguridad Hospital C.CH.C, Santiago, Chile References 1 Urtubia RM, Aguila CM, Cumsille MA. Combitube. A study for proper use. Anesthesia and Analgesia 2000; 90: 958±62. 2 Tanigawa K, Shigematsu A. Choice of airway devices for 12,020 cases of non± traumatic cardiac arrest in Japan. Prehospital Emergency Care 1998; 2: 96± 100. 3 Rumball CJ, MacDonald D. The PTL, Combitube, laryngeal mask airway, and oral airway: a randomized prehospital comparative study of ventilatory device effectiveness and cost-effectiveness in 470 cases of cardiorespiratory arrest. Prehospital Emergency Care 1997; 1: 1± 10. 4 Verghese C, Brimacombe JR. Survey of the laryngeal mask airway usage in 11,910 patients: safety and efficacy for conventional and nonconventional usage. Anesthesia and Analgesia 1996; 82: 129±33. 5 Frass M. The Combitube: Esophageal/ Tracheal double-lumen airway. In: Benumof JL, ed. Airway Management ± Principles and Practice. Mosby-Year Book, Inc., 1996: 444±54. 6 Brimacombe J, Berry A. Laryngeal mask airway cuff pressure and position during anaesthesia lasting one to two hours. Canadian Journal of Anaesthesia 1994; 41: 589±93. 7 Tu HN, Saidi N, Lieutaud T, Bensaid S, Menival V, Duvaldestin P. Nitrous oxide increases endotracheal cuff pressure and the incidence of tracheal lesions in anesthetized patients. Anesthesia and Analgesia 1999; 89: 187± 90. 8 Koppel JN, Reed AP. Formal instruction in difficult airway management. A survey of

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Table 2

Combitube Failed insertion (%) Successful ventilation (%) LMA Failed insertion (%) Successful ventilation (%)

Tanigawa et al.

Rumball et al.

Oczenski et al.

6.9 78.9

86

0 100

10.5 71.5

73

8 92

anesthesiology residency programs. Anesthesiology 1995; 83: 1343±6.

A reply

Thank you for allowing us to respond to the letter from Dr Urtubia and coworkers. We feel it is necessary to clarify some points mentioned in their letter. 1 The authors of the letter report a much lower incidence of complications in 25 patients where a Combitube was inserted with the help of a laryngoscope. We congratulate the authors on these results. However, the comparability of their results with ours is limited as our conclusion precisely refers to `blind insertion of the Combitube'. 2 The authors state that others have described much lower rates of complications: the first publication by Tanigawa et al. [1] describes results from a survey in nontraumatic emergency patients and evaluated three devices for securing the airway including the Combitube and the laryngeal mask airway (LMA). The second publication by Rumball et al. [2] compares several devices, also including the Combitube and the LMA. We have to point out that the scoring system for difficult intubation/insertion used in our study was subjective and served the goal of allowing a correlation when trauma was detected in a patient or a patient reported discomfort on the follow-up. With this scoring system we classified insertion conditions into excellent, good, poor and impossible. According to this classification, 84% of insertions of the Combitube and 92% of LMA insertions were graded as excellent and good.

Data presented in the two studies refer to failed and successful insertion and ventilation of the tested devices. Only the percentage of successful and failed insertion is reported, without any grading. In both publications these numbers were substantially worse than in our investigation. The numbers of successful placements of the Combitube and the LMA in the two studies compared with ours are shown in the Table 2. We point out that the number of cases in our study is much smaller than in the two others, but certainly our data are not worse than those reported in the literature. Again, the goal of our study was to report on complications following the use of the Combitube, tracheal tube and LMA, and not insertion conditions. However, we do not accept that the results we reported are due to ìnappropriate insertion technique or insufficient operator skills'. Furthermore, we had the advantage that Dr Frass is working in Vienna, and he trained us in the correct use of the device. The authors of the letter furthermore state that the rate of complications in our study is much higher than in the studies named above. In contrast to the studies named by the authors of the letter, we prospectively investigated the traumatic effects of the devices by having the patients inspected by an otolaryngologist before and after the use of the devices. Furthermore, Tanigawa et al. recognised that their study probably underestimated the incidence of complications [1]. We believe that our protocol was not biased by such difficulties and our data are valid. 3 Blind insertion vs. manufacturer



recommendations: the authors of the letter refer to a review written by Dr Frass [3], who is not the manufacturer, but the inventor of this device. Although he is closely co-operating with the manufacturer, this textbook chapter is not part of the manufacturer's recommendation. The guidelines that are packed and sold with the device state that `the use of a laryngoscope is not necessary, although it might be helpful' (translated from German into English by the authors). Dr Frass was aware of our protocol, and did not advise us to change the method from blind insertion to laryngoscope-guided insertion. This is understandable as it is the main feature and advantage of this device to allow blind insertion and not to require the use of a laryngoscope. Even in the textbook chapter cited by the authors of the letter [3], Dr Frass recommends the use of the laryngoscope for situations where intubation with direct laryngoscopy fails and the laryngoscope is still in place. Thus, despite the fact that we recognise the use of the laryngoscope as an interesting alternative and possible improvement of the method (although a main advantage is lost), we believe that utilising blind insertion of the Combitube in our study is the valid choice and has to be chosen when evaluated against other devices and methods. 4 The authors suggest that the pressure effects of the cuffs reported in our study could be worsened by over inflation of the cuffs with nitrous oxide. This indeed is relevant, and we regret not reporting our handling of this problem in our manuscript. It is standard procedure during every anaesthetic in our Department to monitor cuff pressure on-line. However, whereas pressure values for tracheal tubes are well known, no such values exist for LMA and Combitube. Thus, our procedure consisted of inflating the cuffs of the Combitube with the recommended volume of air and taking the (very variable) pressure value as baseline for correction of the nitrous oxide effect. With the LMA the cuff was inflated to allow an optimal sealing of the larynx and again this value was taken as baseline for correcting overinflation. This method is very simple and does not exclude that overinflation of the cuffs


is responsible for some of the traumatising effects seen in our study. However, as long as no optimal values for cuff pressure for LMA and Combitube are available, we regretfully have to accept this possible bias. 5 Invalid conclusion: as described above, we believe that the participating anaesthetists were sufficiently trained to allow valid evaluation of the compared devices. Furthermore, this leads to the question of how much experience is sufficient for safe use. Can we regard a device as safe, when during a possibly long training period harm is done to patients? While we do not want to diminish the importance of the Combitube for emergency settings and recognise the need for training programmes to avoid `seeing the device for the first time during efforts to ventilate a failed intubation', we believe that our conclusion is valid. W. Oczenski R. D. Fitzgerald City of Vienna Hospital Lainz, Wolkersbergenstraûe 1, A-1130 Vienna, Austria References 1 Tanigawa K, Shigematsu A. Choice of airway devices for 12,020 cases of nontraumtic cardiac arrest in Japan. Prehospital Emergency Care 1998; 2: 96± 100. 2 Rumball CJ, MacDonald D. The PLT, Combitube, laryngeal mask airway, and oral airway: a randomised prehospital comparative study of ventilatory device effectiveness and cost-effectiveness in 470 cases of cardiorespiratory arrest. Prehospital Emergency Care 1997; 1: 1±10. 3 Frass M. The Combitube: Esophageal/ Tracheal double-lumen airway. In: Benumof JL. eds. Airway Management ± Principles and Practice. Mosby-Year Book Inc., 1996, Chapter 22:444±54.

Nasendoscopy: a useful addition to the anaesthetist's armamentarium

The recent cogently argued editorial by Mason and Fielder entitled `The

obstructed airway in head and neck surgery' (Anaesthesia 1999; 54: 625±8) prompts us to write to urge anaesthetists to include the fibreoptic nasendoscope in their airway assessment armamentarium. Hitherto, the anaesthetic fraternity has regarded the nasendoscope as a surgeon's tool. We discuss below the potential benefits of pre-operative nasendoscopic airway assessment by the anaesthetist. We have found the nasendoscope to be particularly useful for pre-operative airway assessment in patients in whom the larynx may be completely normal but inaccessible or difficult to expose and in those in whom the larynx is distorted or displaced by a tumour or other pathology that impedes visualisation. The surgical nasendoscopic assessment of these patients is often carried out with the patient sitting upright in an outpatient setting. The nasendoscopic view of the larynx recorded in the notes (not always by a consultant surgeon) is sometimes very different from the laryngeal landscape that confronts the anaesthetist. Even in those patients with no symptoms at rest, merely lying them supine and inducing anaesthesia may result in considerable difficulties with ventilation and/or tracheal intubation. This is a potential problem with both supraglottic and pedunculated glottic tumours. The view obtained with a 2.7-mm, short nasendoscope is infinitely superior to that obtained with a standard intubating fibrescope and nasendoscopy carried out pre-operatively in both the upright and supine positions by an experienced anaesthetist will yield valuable information that can be incorporated into the formulation of a management plan. It is a relatively easy procedure to perform and is well tolerated by patients with minimal topical local anaesthesia to the nose. It affords a good opportunity to teach trainees the motor skills and dexterity needed to wield the intubating fibrescope outside the more stressful operating theatre environment. Capital cost may be an issue in some departments. Our surgical colleagues have kindly allowed us to use their equipment on the wards for the best part of the last decade. In an ideal world

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both surgeon and anaesthetist would assess the patient with oro-pharyngolaryngeal pathology together and jointly decide the airway management plan. I. R. Appadurai J. S. Davies University Hospital of Wales, Cardiff CF14 4XW, UK Upper airway obstruction

Bonner and Taylor (Anaesthesia 2000; 55: 290) are mistaken in their statement that I advocated awake fibreoptic intubation in upper airway obstruction (Anaesthesia 1999; 54: 1114). I advocated awake intubation under direct vision using a conventional laryngoscope, a method that served me well in that part of my career when I was meeting these cases. The majority of patients were suffering from postradiation oedema of the larynx. Usually most of the anatomy was unrecognizable; however, the epiglottis remained visible and the airway appeared as a pinhole with a telltale bubble. I found that a normal size tracheal tube would push the oedema aside and enter the trachea, to my, and the patient's, relief. The tube opened the patient's airway, whereas a fibreoptic laryngoscope, if one had been available then, would have blocked what was left of it. I can only hope that if I ever have the misfortune to have upper airway obstruction, and I lose it, that those looking after me do not waste time performing a formal tracheostomy, but establish an airway quickly via the cricothyroid route. T. J. Hawkins Willoughby on the Wolds, LE12 6SY, UK The `correct' application of cricoid pressure

The recent papers in Anaesthesia questioning the use of 44 N force as a standard pressure over the cricoid region during rapid sequence induction raise some interesting points (Anaesthesia 2000; 55: 208±11 and 55: 263±8). Both groups of workers attempted to standardise head

600

position on one pillow. It has been demonstrated elsewhere that head and neck position can alter airway anatomy [1], so presumably the force required to exert `successful' cricoid pressure will vary depending on how the head is positioned at intubation. Many of our emergency intubations take place outside the operating theatre in less than ideal conditions and with a variety of head positions [2]. Most cricoid pressure is performed by anaesthetic assistants and as such can be variable in its efficacy. The regular testing of the pressure applied by these assistants beyond their training is not carried out routinely. The ability of the assistant to act effectively in emergency situations, such as failed intubation, can be crucial in contributing to a successful outcome [3]. Much work has been done recently with the training of unskilled personnel to insert the laryngeal mask airway (LMA) in emergency situations and even to intubate through these devices [4]. However, the problems with aspiration in emergency situations have also received attention and the use of the LMA questioned [5]. Given the knowledge that incorrectly applied cricoid pressure can cause airway occlusion and deformity and that estimates of the force required are dependent on the experience of the anaesthetist and assistant, should there not be some regular review of procedures in this very routine, yet crucial area of anaesthetic practice? P. J. Shirley Aberdeen Royal Infirmary, Aberdeen AB25 2ZN, UK References 1 Buckham M, Brooker M, Brimacombe J, Keller C. A comparison of the reinforced and standard laryngeal mask airway: ease of insertion and the influence of head and neck position on oropharyngeal leak pressure and intracuff pressure. Anaesthesia and Intensive Care 1999; 27: 628±31. 2 Birkinshaw R, McKinnon KA, Kitching G, Ryan B. Intubation in difficult positions. Pre-Hospital Immediate Care 1998; 2: 59±62. 3 Kluger MT, Bukofzer M, Bullock M. Anaesthetic assistants: their role in the

development and resolution of anaesthetic incidents. Anaesthesia and Intensive Care 1999; 27: 269±74. 4 Choyce A, Avidan MS, Patel C et al. Comparison of laryngeal mask and intubating laryngeal mask insertion by the naõÈve intubator. British Journal of Anaesthesia 2000; 84: 103±5. 5 Lockey DJ, Coats T, Parr MJA. Aspiration in severe trauma: a prospective study. Anaesthesia 1999; 54: 1097±109.

Tranexamic acid applied topically to achieve haemostasis

Tranexamic acid is an antifibrinolytic agent that may be administered orally or by intravenous injection to reduce bleeding following procedures such as prostatectomy and dental extraction. Use of this agent is, however, contraindicated in patients with a history of thromboembolic disease. We report a case in which tranexamic acid was used topically to stop bleeding in a patient in whom such a contraindication prevented its intravenous use. A 75-year-old male patient presented for excision of a large left-sided parotid pleomorphic adenoma. His past medical history included hypertension, a gait and balance disorder (believed to be a variant of Parkinson's disease) and transient ischaemic attacks. As a result of the latter he was prescribed aspirin 75 mg and dipyridamole 25 mg daily. One hour after an uneventful excision of the tumour, bleeding and swelling around the neck and face were noted and re-exploration was required. Following an awake fibreoptic intubation, general anaesthesia was re-established and surgical exploration revealed brisk oozing that persisted despite diathermy. The use of intravenous tranexamic acid (Cyclokapron) was considered but because of the patient's history of thromboembolic disease we decided instead to soak gauze swabs with 1000 mg of this agent and apply it directly into the wound. Following this manoeuvre, bleeding ceased and there were no further complications. We have been unable to find any other reports describing the topical use of



tranexamic acid as a means of treating intra-operative haemorrhage. There are, however, reports confirming effective topical application when combined with another haemostatic agent (carbazochrome sodium sulphonate) to reduce bleeding following total knee arthroplasty [1] and also as an enema to stop rectal bleeding [2]. The prompt response to direct application of the drug in our patient suggests a beneficial local effect but we were unable to measure the plasma level to determine the degree of systemic absorption. There is, however, one study (in rabbits) that compares systemic levels of tranexamic acid following topical and intravenous administration [3]. This reported significantly lower serum concentrations following topical application (to the eye) than after intravenous administration. We would therefore suggest that topical administration of tranexamic acid may be of benefit in reducing bleeding from surgical wounds and be associated with less risk of thromboembolism than may occur with intravenous administration. N. Coker D. J. Higgins Southend Hospital, Essex SS0 0RY, UK References 1 Akizuki S, Yasukawa Y, Takizawa T. A new method of haemostasis for cementless total knee arthroplasty. Bulletin ± Hospital for Joint Diseases. 1997; 56: 222±4. 2 McElligott E, Quigley C, Hanks GW. Tranexamic acid and rectal bleeding. Lancet 1991; 337: 431. 3 Damji KF, Noel LP, Peterson RG, et al. Topical versus intravenous administration of tranexamic acid: a comparison of intraocular and serum concentrations in the rabbit. Canadian Journal of Opthalmology 1998; 33: 308± 13.

Postoperative delirium mimicking epilepsy

We read with interest the article by Reuber et al. (Anaesthesia 2000; 55: 74±


8) on postoperative pseudostatus. We think this paper deals with an important clinical scenario about which little has been reported so far. We wish to share our experience in managing a 47-yearold female with a history of long-standing epilepsy who had pseudoepileptic seizures due to postoperative delirium. She had suffered from epilepsy since the age of 14 years, for which she was treated with carbamezepine 300 mg qds and primidone 250 mg qds. Although her last epileptic fit was 14 years ago, she suffered status epilepticus following a decompression of carpal tunnel under general anaesthesia 9 years ago and an epileptic fit associated with collapse following lidocaine and epinephrine dental injection a year ago. Otherwise, she had several uncomplicated operations, mainly for congenital lumbar canal stenosis. During her current admission for elective laminectomy of the 5th lumbar vertebra for decompression of L5 and S1 nerve roots, she was extremely anxious on pre-operative assessment. She failed to relax despite 5 mg of midazolam and 1000 mg of thiopental for induction, and required isoflurane. Muscle relaxation was induced with succinylcholine and anaesthesia was maintained with isoflurane. Her operative course was uneventful. However, during recovery she had two episodes of generalised shaking movements lasting for 3 min each, but not associated with loss of consciousness, incontinence or tongue biting. Her oxygen saturations were maintained during recovery. She remained confused, drowsy but rousable. In view of the epileptiform movements she was intubated and ventilated on the intensive care unit overnight. However, these abnormal movements, which were thought to be àtypical' seizures, persisted in the ensuing week despite the addition of intravenous phenytoin to her anti-epileptic medication. Her CT head scan and blood tests were normal. She also started hallucinating during abnormal movements. Her EEG, when she was confused, agitated and exhibiting abnormal movements, showed no epileptic activity. She was treated for postoperative delirium with droperidol 5±10 mg qds and her epileptiform

shaking movements stopped. She also stopped hallucinating and remained well subsequently. Delirium during the recovery period has been mainly reported in elderly patients [1]. Typical diagnostic criteria for delirium include perceptual disturbance, incoherent speech, disorientation, memory lapses, and reduced awareness and attention. Our patient was at risk of developing postoperative delirium because of epilepsy, anticonvulsant drugs, previous numerous operations and anxiety. She suffered from hallucinations and agitated behaviour associated with abnormal movements, which mimicked epilepsy. She responded to neuroleptic medication, droperidol ± the preferred treatment for delirium. These features suggest that her agitation and shaking during the postoperative period were not due to epilepsy. R. Makker W. Yanny Hemel Hempstead General Hospital, Herts. HP2 4AD, UK Reference 1 O'Keefe ST, Ni Chonchubhair A. Postoperative delirium in the elderly. British Journal of Anaesthesia 1994; 73: 673±87.

An unusual case of postoperative facial swelling

I wish to report an unusual case of postoperative facial swelling. A 24-year-old Afro-Caribbean woman with pre-eclampsia underwent uneventful Caesarean section at 33 weeks gestation for fetal distress. Anaesthesia was provided by an epidural previously sited for labour analgesia. Postoperatively, the patient remained on the delivery unit for high-dependency care. The epidural remained in situ to provide postoperative analgesia, using a bupivacaine and fentanyl infusion. The following morning the epidural was removed and patient-controlled analgesia (PCA) with morphine was started. Approximately 50 min later

601


the patient complained of painful bilateral facial swelling in the region of the parotid glands. The only `new' drug introduced to the patient at that time was morphine, so the PCA was disconnected. The total dose of morphine given was 8 mg. Thereafter, the swelling rapidly subsided and according to the patient this was accompanied by an increased quantity of saliva in her mouth. At no time was there any sign of airway obstruction. Alternative analgesia was provided with codeine phosphate, paracetamol and diclofenac. The rest of her postoperative course was unremarkable. She denied any previous history of parotid swelling, and this was the first occasion on which she had ever received morphine. Morphine is known to reduce the secretion of amylase from isolated parotid acini [1]. However, the ability of morphine to both increase tone and decrease propulsive activity of smooth muscle throughout the gastrointestinal tract is also well recognised [2±3]. These latter effects may be mediated via m receptors. The ducts of the parotid salivary glands are surrounded by myoepithelial cells. These cells resemble smooth muscle cells, and by their contraction they facilitate the movement of glandular secretions [4]. I propose that this patient's facial swelling may have been caused by morphine-induced spasm of the parotid ducts, leading to an accumulation of saliva in the parotid glands. An extensive literature search has failed to find any previous reference to this phenomenon. J. Kenningham Withington Hospital, Manchester M20 2LR, UK

References 1 Miwa Y, Saeki M, Yamaji A, Maeda S, Saito K. Effect of morphine on secretion of amylase from isolated parotid acini. Life Sciences 1996; 59: 1809±19. 2 Vieira ZG, Duarte B, Renigers SA et al. Double-blind ultrasonographic demonstration of morphine induced

602

Figure 2 Apparatus used for ambient oxygenation during one-lung ventilation. The system consists of a 500-ml wide-bore reservoir tubing attached by a T-piece to the double-lumen tube connector. Oxygen is administered via the side-arm of the T-piece.

spasm of the common bile duct. Anesthesiology 1988; 69: A347. 3 Aitkenhead AR. Anaesthesia and bowel surgery. British Journal of Anaesthesia 1984; 56: 95±101. 4 Sicher H, Bhaskar SN. Orban`s Oral Histology and Embryology, 7th edn. Saint Louis: CV Mosby, Company 1972; 278.

Ambient pressure oxygenation via the nonventilated lung during video-assisted thoracoscopy

One-lung ventilation (OLV) during video-assisted thoracoscopy is mandatory in order to ensure collapse of the lung on the operative side. During OLV ventilation, opening of the nonventilated lung to the ambient air is usually established before the chest is opened, and hence before the nonventilated lung is collapsed. In the presence of pleural adhesions, lung collapse may be delayed even after the pleura is opened. Pfitzner et al. have experimentally shown that positive-pressure ventilation of one lung, while the chest is closed, will generate transient pressure changes in the contralateral hemithorax which, in

turn, will generate tidal movement of air, and therefore nitrogen, out of and back into the nonventilated lung [1]. Ambient pressure oxygenation to the nonventilated lung is recommended to exclude air entrainment, and consequently to enhance lung collapse and decrease the shunt fraction in the nonventilated lung [2]. The present report describes a simple apparatus for providing ambient pressure oxygenation in patients undergoing video-assisted thoracoscopy (Fig. 2). The technique was used in five adult patients undergoing thoracoscopy. Following induction of general anaesthesia and double-lumen intubation, two-lung ventilation (TLV) was initially used for 15 min. The apparatus was then attached to the double-lumen connector of the nonventilated lung on the thoracoscopy side, upon initiation of contralateral one-lung ventilation, and before opening the pleura. Oxygen flow of 10 l.min21 was delivered via the Tpiece. After 15 min of ambient pressure oxygenation of the nonventilated lung, the T-piece was disconnected and the nonventilated lung was left open to room air. Throughout this procedure, the patient was ventilated with isoflurane in 100% oxygen. The mean arterial



Po2 during contralateral one-lung ventilation was significantly higher when ambient oxygen was used (307 ^ 152 mmHg), as compared with that achieved when the nonventilated lung was open to room air (136 ^ 63 mmHg). The results show that adequate oxygenation can be achieved during thoracoscopy when ambient pressure oxygen is delivered by a T-piece system attached to the nonventilated lung before initiation of OLV and prior to the chest being opened. Ambient pressure oxygenation should be maintained throughout thoracoscopy. The technique, as a method of excluding nitrogen from the nonventilated lung, may not only improve oxygenation during OLV, but may also enhance collapse of the nonventilated lung on the thoracoscoped side. A. Baraka A. Lteif M. Nawfal S. Taha M. Maroun S. Khoury M. Jalbout American University of Beirut Medical Center, 6044 Beirut, Lebanon References 1 Pfitzner J, Peacock MJ, McAjeer PT. Gas movement in the non-ventilated lung at the onset of single-lung ventilation for video-assisted thoracoscopy. Anaesthesia 1999; 54: 431±43. 2 Pfitzner J, Peacock MJ, Daniels BW. Ambient pressure oxygen reservoir apparatus for use during one-lung anaesthesia. Anaesthesia 1999; 54: 454±8.

The effect of pre-emptive acupuncture treatment on analgesic requirements after day-case knee arthroscopy

I read the article by Gupta et al. (Anaesthesia 1999; 54; 1204±6) with great interest because there rarely appear


articles about acupuncture and its analgesic effects. The conclusion of the authors that àcupuncture analgesia has no additional effect when given under anaesthesia to patients undergoing knee arthroscopy' didn't surprise me at all. The conditions under which the work was done are contrary to the long established theory and practice of acupuncture. The article is a hybrid between Western medicine and the Traditional Chinese Medicine (TCM), which are two different sciences that should not be mixed up. TCM with its philosophy has never been Cartesian. If the study had been directed at, for example, the postoperative effects of acupuncture on reduction of oedema and relieving pain in the first 24 h, the article would have been much more useful. They could, for example, perform arthroscopy under acupuncture analgesia. These are situations where acupuncture retains its effectiveness even when much of Chinese philosophical background is discarded. The fact that acupuncture was administered after induction of general anaesthesia by itself excludes any effect of acupuncture because under the conditions of interruption of neurophysiological integrity the effect of needles is excluded. The use of needles of 1 inch was inadequate as the depth of corresponding points is mostly deeper: Spleen 9 (Yinlingquan, SP 9) is situated at 1±2 in. Spleen 10 (Xuehai, SP 10) is situated at 1±1.5 in. Stomach 34 (Liangqui, ST 34) is situated at 1 in. Stomach 36 (Zusanii, ST 36) is situated at 1±1.5 in. Important points like: B 20 (Pishu), B 40 (Weizhong), B 54 (Zhibian), B 60 (Kuniun) and Liv 8 (Ququan) were not used. Even if patients were awake, De Qi sensations would not have been achieved for certain with needles of 1 in. (De Qi is closely related to the therapeutic effect), let alone in the unconscious, anaesthetised patients. The needles were also inserted without confirmation that they were inserted at the correct points. In addition, a constant electrical stimulation was not used.

The distal point of large intestine 4 (Hegu, L1 4) is poorly effective in curing postoperative knee pain, though can be very useful in diseases of head, neck and upper limbs. In their discussion the authors realised that à properly functioning nervous system may be essential for acupuncture analgesia to be effective' which leaves me wondering why they insisted on finishing the work in an anaesthetised patient. The fact is that acupuncture is effective in post-traumatic situations and not as pre-emptive pain treatment after daycase knee arthroscopy A. Pelimon HoÃpital ReÂgional Porrentruy, 2900 Porrentruy, Switzerland A reply

Thank you for the opportunity to reply to Dr Pelimon's letter; he makes several points and we would like to reply to each in turn. The conditions under which we did the study were designed, to the best of our ability, to allow a double-blind randomised controlled trial. This has traditionally been very difficult in studies involving acupuncture because, of course, the conscious patient is well aware when he/she has a needle inserted. Although sham points have been used, there remains the problem of De Qi sensation, which would potentially unblind the subject. We felt that no knowledge at all of group allocation could arise (as indeed it did not) if acupuncture was performed under general anaesthesia. We would dispute the idea that two different sciences should not be `mixed up'; the history of science is littered with examples of the benefits of adopting ideas and techniques from disparate disciplines; we feel instead that such cross-fertilisations are potentially very fruitful The labour that we invested was used to look at the levels of pain in the first 24 h postoperatively. Oedema could also have served as an end point; however, this would have been complicated because of the variable amount of leakage of irrigation fluid into the soft tissues around the knee during the surgery.

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It seems unlikely that knee arthroscopy could be performed under acupuncture alone, if as Dr Pelimon states `the fact is that acupuncture is effective in posttraumatic situations, and not as preemptive treatment'. It might indeed be the case that knee arthroscopy can be performed under acupuncture analgesia, but we doubt whether our ethics committee would have allowed a trial to demonstrate it, and we would also anticipate difficulties in enrolling patients. We agree that an explanation of our findings is that `general anaesthesia by itself excludes any effect of acupuncture, because under the conditions of interruption of the neurophysiological integrity the effect of the needles is excluded' because as we stated ìt may be that a properly functioning nervous system is necessary for acupuncture analgesia to be effective'. Turning to the acupuncture points used: Dr Pelimon suggests that the use of needles of one inch (2.5 cm) was not adequate as the depth of the acupoints used in our study are mostly deeper, between 1 and 2 inches. The depths of the acupoints we used in our study are 2±3 cm, LI-4 being just 1±2 cm [1]. In a study by Christensen et al. [2] on acupuncture treatment for severe knee osteoarthritis, they were able to elicit `Di Qi' sensation at ST-34, ST-36, SP10 and LI-4 at a depth of 1±1.5 cm in awake patients and had a positive outcome in terms of pain relief. The important points mentioned by Dr Pelimon such as B220 (B±bladder), B240, B254/60, lie on the posterior aspect of the lower limb. Thus we would have had to turn the anaesthetised patient prone to stimulate these points. This would have necessitated a different anaesthetic technique involving intubation, and was thought unsuitable. We agree that a constant electrical stimulation was missing, but this was replaced by manual stimulation for 5 s every 5 min and just before needle removal. LI-4, though a very important point to treat diseases of head, neck and upper limbs, is indicated in all forms of pain treatment and is one of the most frequently used acupoints for pain. Most of the studies in the western literature so far have looked at the antiemetic effect of acupoints P-6 in

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anaesthetised (general anaesthesia or local anaesthesia) patients and have concluded that acupuncture is not anti-emetic when given under anaesthesia [3]. A study by Chang et al. [4] concluded that acupuncture analgesia is abolished when the local anaesthetic procaine was infiltrated in the deep tissues around the acupuncture points. There are no double-blind studies to prove or disprove the analgesic effect (rather than anti-emetic effect) of acupuncture treatment when given under general anaesthesia. A further study would be needed to assess the possible analgesic effect of acupuncture at these (or other) points without prior general anaesthesia, but it is not clear how such a study would be blinded adequately to the patients. J. M. Sizer Bedford South Wing Hospital, Bedford MK42 9DJ, UK References 1 Stux G. Channels. Organs, and Points. In: Stux G, Pomeranz B, eds. Basics' of Acupuncture. London: Springer-Verlag, 1995: 72±187. 2 Christensen BV, Iuhl IU, Vilbek H, Bulow HH, Dreijer NC, Rasmussen HF. Acupuncture treatment of severe knee osteoarthrosis. A long-term study. Acta Anaesthesiologica Scandinavica 1992; 36: 519±25. 3 Vickers AJ. Can acupuncture have specific effects on health? A systematic review of acupuncture antiemesis trials. Journal of the Royal Society of Medicine 1996; 89: 303±11. 4 Chiang CY, Chang CT, Chu HL, Yang LE. Peripheral afferent pathways for acupuncture analgesia. Scientia Sinka 1973; 16: 210±17.

Electroencephalographic arousal response during tracheal intubation and laryngeal mask airway insertion after induction of anaesthesia with propofol

Having studied the effect of tracheal

intubation and other noxious stimuli on evoked potentials of the EEG [1, 2] I have no doubt that the arousal in response to airway manipulation detected by Inada and colleagues (Anaesthesia 1999; 54: 1150±4) does indeed occur. In order to detect a difference in the degree of arousal between two different stimuli however, steady-state plasma concentrations of anaesthetic must be present before the stimulus is applied. By ensuring this, one can exclude variations in anaesthetic plasma concentrations as a cause for arousal. This is particularly true when using intravenous anaesthetics such as propofol, when it is extremely difficult to predict plasma concentrations. It is a pity that although the patients in this study had arterial lines, plasma propofol concentrations were not measured to allow an accurate comparison between patients to be made. In addition, although it seems from the EEG data that significant arousal occurred following intubation, the lack of a control group, i.e. a group of unintubated patients, does not exclude the fact that arousal may have occurred simply because propofol levels were too low to keep the patients asleep. In fact, relative delta power began to fall and alpha and beta power began to rise 1± 2 min before airway manipulation. This implies that the patients were getting lighter before they were intubated. The investigators cannot conclude from this study that the degree of EEG arousal caused by intubation and laryngeal mask insertion is the same. In order to do this, it is important to include a proper control group in whom the stimulus is not applied and ensure that steady-state conditions exist prior to applying the stimulus. M. Brunner Northwick Park, Harrow HA1 3UJ, UK References 1 Brunner MD, Crabb IJ, Millett SV, Thornton C, Newton DEF. Alfentanil obtunds the increase in Pa amplitude associated with intubation in a dose



dependent fashion. Anesthesiology 1995; 83: 3A:A301. 2 Brunner MD, Nathwani D, Rich P, Thornton C, Dore C, Newton DEF. The effect of suxamethonium on the auditory evoked response in man. British Journal of Anaesthesia 1996; 76: 34±7.

A reply

As Dr Brunner points out, any possible differences in the depth of anaesthesia between patients at insertion of the airway can be a confounding factor, and a decrease in propofol concentration might have caused the EEG arousal pattern detected in our study. However, since we randomised patients into two groups to receive either a tracheal tube or a laryngeal mask airway (LMA), theoretically there should be no difference between the groups in the depth of anaesthesia at insertion of the airway. To study the degree of arousal during insertion of an airway, it is necessary to ensure the standardised steady-state plasma concentrations of anaesthetic at insertion of the airway; but this was not our aim. The main aim of our study was to study `whether noxious stimulations of different intensity cause different degrees of EEG arousal response'. We used different noxious stimuli as tracheal intubation and insertion of an LMA, since it is known that, compared with LMA insertion, laryngoscopy and tracheal intubation produce a significantly stronger noxious stimulus to haemodynamic changes. We found that there was no significant difference in the EEG changes between groups in the presence of a significant difference between groups in the intensity of haemodynamic stimulation. T. Inada K. Shingu Kansai Medical University Hospital, Osaka 570±8507, Japan A leaking Biovalve intravenous catheter

We wish to report an unusual incident regarding the failure of a Vygon


Biovalve 14-gauge intravenous cannula. During a routine elective operating theatre case, a Vygon Biovalve 14gauge cannula was inserted in the dorsum of the left hand of the patient prior to induction of anaesthesia and secured with tape in the usual manner. The anaesthetist then turned his attention to the drawing up of induction agent, briefly returned his attention back to the patient to notice a steady flow of blood exiting from the injection port of the cannula. Approximately 15 ml of blood was lost via the faulty valve mechanism. We feel that this represents a potentially life-threatening fault in this type of cannula, especially when venous access sites are obscured by surgical drapes, and would like to draw your attention to its possible occurrence. J. C. J. Wright J. J. Tarpey Warwick Hospital, Warwick CV34 5BW, UK A reply

After receiving the leaking Biovalve cannula from Warwick Hospital and completing our examination of the device, we are pleased to be able to offer a reply to Drs Wright and Tarpey. We have found that the silicone tube that sits inside the hub of the cannula acting as a one-way valve had been distorted and was not fully covering the port. Whilst we have not been provided with a Lot number with which we can definitively identify this device, we believe that it is in fact a model that was produced prior to being upgraded to be manufactured using a state of the art fully automated assembly machine. This machine performs a number of inprocess tests including a measured flow test and would identify and automatically remove any device that does not meet the flow parameters; in this case a high measurement would have been recorded. Over the years in which the Biovalve has been manufactured, we only have one other report on our database where a blood leak through the injection port was discovered in use. This occurred in

1997 and unfortunately the device was discarded before we were able to examine it and confirm the cause of the problem. From this we believe that this is an isolated incident. We sell some 4 million Biovalves a year in the UK alone and always hope that there will be no problems. In reality, we accept that occasionally we will have a product with a problem, such as occurred with this Biovalve, and for this we offer our unreserved apologies and our assurances that we will continue to work towards the ultimate goal of zero product problems. This incident has highlighted an area where, as a manufacturer, we would ask for the help of the readers of Anaesthesia in reducing the potential numbers of problems encountered through faulty devices. We found out about this incident a month, or possibly more, after it occurred when we were offered the opportunity to reply to the letter sent to Anaesthesia. We immediately checked with the Medical Devices Agency and found it had not been reported to them, so that our first contact with the hospital was that same day, when we were able to recover the cannula for examination. If anyone has a problem with a device, reporting an incident to either the manufacturer (we think we can speak on behalf of the majority of reputable manufacturers), or the MDA should be done as quickly as possible. This gives the best possible opportunity to examine for batch-related problems and, when this is found to be the case, a speedy product recall. Any delays may result in further incidents and, as Drs Wright and Tarpey point out, with a potentially life-threatening fault, such an incident may have a very different ending as happened this time. The MDA, as well as many other excellent services, have an Adverse Incident Centre where either the user or the manufacturer, who has a legal obligation to do so, may report an Adverse Incident. The MDA will then follow through the report with both the user and manufacturer in order to try to stop any recurrence of that incident or any similar incidents. The MDA Adverse Incident Centre can be

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contacted on 0171 9728080 or by fax on 0171 9728109. G. Milward Technical Support Services, Vygon (UK), Cirencester GL7 1PT, UK

Editorial comment We remind readers that they have a professional responsibility to report any incident involving faulty equipment to the manufacturer or the Medical Device Agency at the earliest opportunity. Leaking vaporiser

With reference to the editorial by Cartwright and Freeman (Anaesthesia 1999; 54: 519±20), leakage of anaesthetic agent seems to be one of the commonest problems associated with vaporisers. Typically, an average hospital has a large number of anaesthetic machines and even larger variety of vaporisers in use. Financial constraints prevent achievement of uniformity of the anaesthetic equipment at various locations of the hospital. The process of mounting and demounting of the vaporisers on the backbar of the anaesthetic machine during an anaesthetic procedure is potentially risky. Transporting the vaporiser from the anaesthetic room to the operating theatre during the course of the transfer of the anaesthetised patient is a further source of complications. I wish to report a problem that occurred as a result of transfer of the vaporiser during one of the anaesthetic procedures. Routine check of the anaesthetic machines in the anaesthetic room and the operating theatre was performed at the start of the list. Both these machines had enflurane vaporisers Ènfluratec' (Tec 3) in place. The first half of the list went uneventfully. A patient listed halfway through the list had a history of epilepsy; therefore, isoflurane was selected as the agent of choice for the anaesthetic. However, there was only one isoflurane vaporiser available for the anaesthetic room and the operating theatre. The vaporiser (Ohmeda, Isotec 5) had been tested and found to be compatible with the backbar of the machine in the

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Figure 3 The close up of the Isotec 5 vaporiser showing downwards displacement of the locking lever of the key filler port (a) and the partially open draining valve tap (b).

anaesthetic room as well as that in the operating theatre. The anaesthetic was commenced in the anaesthetic room using an intravenous induction and a laryngeal mask was inserted. Anaesthesia was maintained with a mixture of oxygen, nitrous oxide and isoflurane. The patient was transferred to the operating room and simultaneously the isoflurane vaporiser was dismounted from the machine in the anaesthetic room and remounted on the backbar of the anaesthetic machine (Datex Flexima) in the operating theatre by the theatre assistant. On reconnection of the breathing circuit to the patient, inability to achieve a satisfactory pressure in the circuit was noticed despite high flow of the gases. The patient's lungs were being ventilated manually at this stage. A systematic inspection of the assembly revealed a steady drip of the contents (isoflurane) from the Isotec 5 vaporiser.

On closer inspection, the locking lever of the key filler port on the left side of the vaporiser (a) was noted to be displaced downwards; additionally, the valve tap at the base of the vaporiser (b) was found to be partially open, resulting in the drip (Fig. 3). The situation was rapidly rectified by repositioning the levers in the correct place and the gastight seal was restored. The vaporiser was topped up and there was no problem in maintaining the depth of anaesthesia. It appeared that the valve tap had probably been accidentally knocked open as the vaporiser was being remounted on the backbar of the anaesthetic machine in the operating theatre. As seen in Fig. 4, there was a very snug fit between the frame of the anaesthetic machine and the base of the Isotec 5 vaporiser. Additionally, the space between the left-hand side of the Isotec 5 vaporiser bearing the lever for the key



Figure 4 The double vaporiser assembly showing the tight fit between the two

vaporisers and the frame of the anaesthetic machine in relation to the base of the Tec 5.

filler and the filling port of the adjacent Enfluratec vaporiser was very tight. This left no room for fingers to support the bulky Tec 5 vaporiser at its base or on the left side. The only available space was towards the lower outer right-hand corner of the Tec 5. It is easy to see how the draining valve tap near the base could have been accidentally flicked open during a rushed procedure.

Fortunately, due to timely intervention, the drop in the end-tidal concentration of the vapour was prevented. Figure 5 shows a much larger space available between the two adjacent vaporisers when the relative positions of the two were reversed; however, the tight vertical fit with the Tec 5 remained unchanged. This case illustrates the fact that the problems can occur despite adequate

checking of the equipment. The draining valve tap of the Tec 5 vaporiser is rather easily opened unlike others, where emptying of the vaporiser would involve a series of deliberate manoeuvres. The valve tap is not secured by any locking device. Additionally, it might be difficult to spot a partially open valve when viewed from the front. The accidental opening of the valve is thus a potential problem. These vaporisers have been around for nearly 10 years. Personal communication with the quality control manager at the DatexOhmeda UK revealed a couple of other reports of accidental draining of the Tec 5 vaporiser. In the first one the valve was entangled with the monitoring leads and another occurred during a cleaning process of the equipment. As it would be a monumental task to alter the design of the vaporiser, it is suggested that the valve tap be secured with some tape during use as well as for transfers. The spillage of the anaesthetic agent not only results in environmental pollution, it is also likely to damage the surface of the machine underneath. In an ideal world, every anaesthetic machine would have a dedicated vaporiser for the relevant anaesthetic agent, thus obviating the need for transportation of vaporiser from one location to another mid-anaesthetic. Despite the best of efforts, it might not be possible to equip all the machines in such a way. One solution would be to anaesthetise the patient in the operating theatre. This would abolish the need for duplication of the equipment in the anaesthetic room and the operating theatre. Furthermore, the hazards associated with the transfer of the equipment and the anaesthetised patient from the anaesthetic room to the operating theatre would be eliminated. S. B. Vohra City Hospital, Birmingham B18 7QH, UK

A reply Figure 5 The double vaporiser assembly with the positions reversed.


Thank you for giving me the opportunity to reply to Dr Vohra's letter

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regarding the difficulty experienced when mounting Datex-Ohmeda Tec 3 and Tec 5 vaporisers on a Flexima 1 anaesthesia workstation. We assembled an identical Flexima 1 workstation in our service centre using the vaporiser configurations shown in Dr Vohra's figures. The results obtained were the same as those reported by Dr Vohra. There was little room to place lifting fingers under either vaporiser, making the mounting operation very difficult. The Tec5 was an interference fit with the floor of the Seletatec mounting block tray. Clearly, the temptation under these circumstances is to grasp the vaporiser by the side faces at the point where the Tec 5 filler is located. This may result in an accidental opening of the drain control lever when the fingers are removed from the narrow gap between the two vaporisers. Picking up the vaporiser by the percentage control knob situated on the top of the vaporiser is similarly not recommended, particularly in the case of the Tec 3 where there is a direct link between the control knob and the rotary valve controlling the flow of anaesthetic agent. We asked Dameca, the manufactures of the Flexima 1 anaesthetic workstation, which vaporisers had been recommended by them for this machine when it was originally placed on the market? Dameca said that the original machines were manufactured to take the Datex-Ohmeda Tec 4 vaporisers, which are similar to the Tec 5 but much shorter. We fitted Tec 4 vaporisers to the Flexima 1 and found no difficulty in supporting the weight of the vaporiser from below without trapping fingers between the vaporiser bottom and the mounting block tray. Tec 3 vaporisers are not recommended for this machine and in fact cannot be fitted unless the lockout pins are removed from the backbar, an operation that we do not recommend. Dameca also advised that later versions of the Flexima 1 were manufactured with the backbar set higher above the mounting tray, permitting the satisfactory fitting of Tec 5 vaporisers. It may be possible to modify these earlier machines to the later standard.

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From our response you see that the compatibility of vaporiser to workstation is not a simple matter. We recommend that vaporisers of a type whose compatibility has been validated by the original manufacturer are used to avoid similar problems. Should the user wish to use alternative items they should ask their equipment supplier to confirm compatibility. M. Kersley Quality, Safety and Environment Manager for Datex-Ohmeda, Hatfield AL9 5EN, UK A `groovy' fibrescope modification

Delay in passage of a tracheal tube during fibreoptic intubation risks patient hypoxia. Insufflation of oxygen

via the suction or instrumentation port of the fibrescope will help prevent this and will also prevent misting of the objective [1]. Since the lever activating the suction valve has to be continuously held down on most fibrescopes to provide a continuous supply of gas, this makes for an extremely awkward grip on the instrument. We have developed a simple modification of the Olympusw LF-TP (Olympus Optical Co. Ltd, Tokyo, Japan) portable fibrescope suction valve, which allows a continuous oxygen stream to be started and stopped at will. The suction valve of this type of instrument (MD493) is surrounded by a plastic cowl with two vertical slots in the wall. These slots allow the flat metal bar of the suction lever to be depressed, thus actuating the valve. The cowl also provides the

Figure 6 The modified plastic cowl.



mounting point for the single-use biopsy valve (MAJ-210). By filing a small (3 mm) horizontal groove or slot at right angles to the existing vertical slot close to the base of the cowl, the actuating bar can be slid into this whilst depressed, thus freeing the grip for holding the fibrescope (Fig. 6). When oxygen is not required the lever can be `clicked' out of the groove and returns automatically to the òff ' position. The best size of file for this purpose is a flat needle file approximately 5 mm wide and 1.5 mm thick. We have forwarded the prototype cowl via Keymed UK to development staff at Olympus for their consideration of this as a permanent modification for future instruments. J. H. MacG. Palmer D. R. Ball Dumfries and Galloway Royal Infirmary, Dumfries DG1 4AP, UK Reference 1 Benhumof JL. Management of the difficult adult airway with special emphasis on awake tracheal intubation. Anesthesiology 1991; 75: 1087±110.

Reinforced laryngeal mask airway severed by biting

I would like to respond to the report by Quinlan of a severed reinforced laryngeal mask airway (Anaesthesia 2000; 55: 186). The manufacturers, IntaventOrthofix, have distanced themselves from the name `reinforced laryngeal mask'. The correct name of the device is the Flexible Laryngeal Mask Airway (FLMA). In the instructions for use it is clearly stated that the flexometallic tube is kink proof, but not bite proof and cannot withstand strong compressive forces [1]. Further, it is recommended that a bite block be used in cases where an FLMA is used. Although surprising that a patient emerging from anaesthesia could bite through the wire, reported evidence serves as a reminder that the instructions for use should be adhered to, and use of the correct device name


may avoid confusion as to its properties. It is also currently recommended practice to use a size 5 in adult males. C. Stonell Royal Berkshire Hospital, Reading RGI 5AN, UK Reference 1 Brimacombe JR, Brain AIJ, Berry AM. Laryngeal Mask Airway Instruction Manual, 4th edn. 1999; 23.

Ambiguous drug labelling on ampoules containing local anaesthetic solution

We would like to bring to your readers' attention a case of confusing drug labelling. At our request to the anaesthetic nurse to provide us with a 10-ml ampoule of bupivacaine 0.5% with epinephrine (adrenaline) 1 : 200 000 for surgical wound infiltration, we were provided with an ampoule with the following label: bupivacaine with epinephrine 0.5%. As it was not clear to us whether this constituted a 0.5% bupivacaine or 0.5% epinephrine solution we proceeded to further checks of the packaging of the ampoule which revealed the same ambiguous drug label. Only the box containing the batch of ampoules from which our ampoule was drawn stated unequivocally an epinephrine concentration of 10 mg.ml21 and a bupivacaine concentration of 5 mg.ml21. Previous ampoules as well as their packaging provided clear unequivocal labelling of concentrations of epinephrine and bupivacaine (Fig. 7). We would like to advocate a return to the previous method of drug labelling to avoid confusion. S. Gupta J. W. Zwaal Kingston Hospital, Kingston Upon Thames KT2 7QB, UK

A reply

AstraZeneca would like to make the

Figure 7

following comments in response to the letter by Drs Gupta and Zwaal concerning the change in labelling of Marcainw and epinephrine. We would firstly like to take the opportunity to reassure our customers that the formulation of the product has not changed in any way. Every product must have the full registered trade name of the product (i.e. that listed on the product licence), clearly marked on the outer packaging and individual components. The registered names of the two presentations are: Marcain with epinephrine 0.5%; and Marcain with epinephrine 0.25%. This appears on the outer packaging and also the individual ampoules. In addition, the amount of epinephrine is quoted on the outer packaging and is expressed as epinephrine tartrate 10 mg.ml21, which is equivalent to 5.5 mg.ml21 base. In response to recent customer feedback concerning the change in labelling of the product, we are currently planning to amend the labelling on both outer cartons and individual ampoules, to clearly indicate the strength of both

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the bupivacaine and the epinephrine. We hope that these amendments will make the labelling more convenient to our customers. We would like to reiterate that no change in the formulation of the product has occurred, and that the product can continue to be used in accordance with current medical practice. R. Rowsell Medical and Regulatory Affairs Director, AstraZeneca, Kings Langley WD4 8DH, UK Paediatric intensive care transfers

We write to express our concern about the current trends in paediatric intensive care. We work in a district general hospital and recently managed an 18month-old with acute epiglottitis, a rare event nowadays following HIB vaccination. We followed the standard teaching using oxygen and halothane (we were not brave enough to use sevoflurane), to `breath the child down' in the operating department. Following successful intubation, vascular access and full monitoring were established. We kept the child ventilated, paralysed with atracurium and anaesthetised in the theatre department, and waited for the paediatric intensive care team from a local teaching centre to pick the child up. They duly arrived and we handed over to the team. They wanted more vascular access and commenced various infusions for transfer. After the handover we continued with other duties and thought that everything would be fine in the hands of the experts from the teaching centre. While R.G. was changing he was quickly summoned to assist with the child again who had coughed the tube out. Neither the consultant paediatric intensivist nor the registrar could reintubate the child. R.G. breathed the child down again and re-intubated it, this time showing the laryngoscopic findings to the paediatricians who had never seen the condition before. A 40mile ambulance journey followed and

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the child made a full recovery. However, this case has some worrying features, which we would like to raise. Firstly, is it safe to transfer a critically ill child 40 miles with a team that cannot re-intubate the patient if a problem occurs? Would we send a ventilated head injured patient in the back of an ambulance with a surgical house officer? Second, the rush to transfer to a specialist unit may be satisfactory in large urban areas but in East Anglia there are large distances between district general hospitals and the specialist centres. Many patients who are now routinely transferred were well managed in our own units until a couple of years ago. We need a return to common sense. District general hospitals, if they have the expertise, should be encouraged to perform the initial resuscitation of the severely ill child and the following 24± 48 h of intensive care. This used to be the case in our hospital and most children so treated did very well. It was the agreement to transfer to a PICU if, after this initial period, more specialist help was needed. This meant that the patient was transferred electively with the patient in as stable a condition as possible. The current situation of the knee jerk referral and transfer to a specialist centre has two very bad outcomes. One is to deskill the very hospitals that are responsible for saving the child's life, and will continue to have to do so. Two is that transfer occurs at the very worst time for the patient, when physiology is most compromised. Talking to our paediatric colleagues has led us to believe they share very similar views. The immediate transfer of all paediatric patients needing intensive care may not be the best solution and a rethink is needed. R. Griffiths H. Smith Peterborough District Hospital, Peterborough PE3 6DA, UK Pre-operative fasting in the older child

In the past 2 years, three surveys have been published looking at pre-operative

fasting practices in children [1±3]. In each of these surveys, the majority of paediatric anaesthetists in three countries stated that they would restrict solid food intake in a child older than 3 years for at least 6 h pre-operatively. Two recent cases at our hospital, which came to light through our critical incident reporting scheme, suggest a longer period of fasting for solid foods may be necessary. Case 1. A 6-year-old boy presented for circumcision under general anaesthesia on an outpatient basis. He had been fasted for solid food for 8 h. Anaesthesia was induced with propofol and fentanyl, and maintained using a laryngeal mask airway (LMA) with isoflurane and nitrous oxide in oxygen. A penile block was performed for postoperative analgesia. On removing the LMA at the end of the operation, the patient regurgitated a large amount of semidigested solid food. No morbidity ensued. On further questioning of the child and parent postoperatively (in a nonconfrontational manner), it became apparent that the child had had a large meal approximately 9 h preoperatively, but no solids after that. Case 2. A 10-year-old girl presented for unilateral inguinal herniotomy under general anaesthesia on an outpatient basis. She had been fasted for solid foods for 8 h. Anaesthesia was induced with propofol and fentanyl, and maintained using an LMA with isoflurane and nitrous oxide in oxygen. An ilio-inguinal nerve block was performed for postoperative analgesia. On skin closure by the surgeon, the patient suddenly regurgitated with vomit coming out through the proximal end of the LMA; the vomit contained semidigested food. The patient was intubated, surgery completed and no morbidity ensued. On further nonconfrontational questioning of the child and parent postoperatively, ingestion of solid food within 8 h of surgery was denied. Most solid food exits the stomach within 4 h. Gastric emptying can be greatly prolonged in children by anxiety, stress or pain. It is reasonable to assume that most children will feel anxious the night before surgery and gastric emptying may be prolonged; the two cases we



report provide some evidence of this. The normal practice in our hospital is to fast children older than 12 months for 6 h for solid foods and 2 h for clear fluids pre-operatively. We are revising this guideline on a trial basis to no solid food intake for 12 h and no clear fluids for 2 h pre-operatively. Two published series on aspiration of gastric contents in children suggest that aspiration pneumonitis is an uncommon problem, and that it causes much less morbidity and mortality than commonly supposed [4, 5]. Nevertheless, it would seem prudent to avoid aspiration if possible. If after audit, our new fasting guidelines are shown to decrease the incidence of peri-operative vomiting, we shall implement them on a permanent basis. G. M. Sanders Medway Hospital, Gillingham ME7 5NY, UK References 1 Ferrari LR, Rooney FM, Rockoff MA. Preoperative fasting practices in pediatrics. Anesthesiology 1999; 90: 978±80. 2 Emerson BM, Wrigley SR, Newton M. Pre-operative fasting for paediatric anaesthesia. A survey of current practice. Anaesthesia 1998; 53: 326±30. 3 Haas U, Motsch J, Schreckenberger R, Bardenheuer HJ, Martin E. Premedication and preoperative fasting in pediatric anaesthesia. Results of a survey. Anaesthesist 1998; 47: 838±43. 4 Borland LM, Sereika SM, Woelfel SK et al. Pulmonary aspiration in pediatric patients during general anesthesia: incidence and outcome. Journal of Clinical Anesthesia 1998; 10: 95±102. 5 Warner MA, Warner ME, Warner DO, Warner LO, Warner EJ. Perioperative pulmonary aspiration in infants and children. Anesthesiology 1999; 90: 66± 71.

The stress response in children during laparoscopic abdominal surgery

I was saddened to note that the first


scientific paper in Anaesthesia in the new millennium made little reference to anaesthesia itself. Bozkurt et al. (Anaesthesia 2000; 55: 5±9) studied the endocrine and metabolic responses of 29 children undergoing operations for abdominal pain. The paper discusses various factors affecting the responses to surgery including the size of the skin incision, the amount of tissue damage and the effects of the pneumo-peritoneum. However, the effects of anaesthesia are ignored. It has been known for some time that in the early peri-operative period regional anaesthesia attenuates (or may even abolish) the neuroendocrine response to surgery [1±2] compared with patients undergoing the same operation but with a general anaesthetic. The metabolic profiles tend to become similar by 24 h, perhaps because of the effects of fasting and/or tissue damage. Barker et al. [3] showed that even in operations where there was virtually no tissue damage, there might be a doubling of the plasma cortisol concentration from a baseline before anaesthesia started until 60 min after the end of surgery. The same group [4] subsequently showed that the emergence from anaesthesia itself has a significant effect on the plasma cortisol level that had previously been masked by the stress response to surgery. They compared three groups undergoing cataract surgery. Two of the groups had general anaesthesia alone (GA) and retrobulbar block alone (RB). The third group (GA 1 RB) had a general anaesthetic followed by a retrobulbar block before surgery. There was no significant difference in cortisol levels between group GA 1 RB and group RB until the end of surgery. However, the serum cortisol level in group GA 1 RB then doubled in the first 30 min post surgery until there was no significant difference compared with group GA. Bozkurt et al. measured the cortisol levels from 5 min after induction until extubation. All the metabolic indicators that they measured were within the normal ranges and there were no significant differences between the final

values in the two groups of patients. Induction and emergence are possibly the most important parts of anaesthesia and the neuroendocrine markers of the response to òperations' seem to underline this point. Perhaps if the anaesthetists hadn't been outnumbered as authors then this point would have been addressed. It is clear that certain types of laparoscopic surgery offer significant advantages to patients in terms of recovery and complication rate when compared with the òpen' alternatives. However, what still remains far from clear is the meaning of the changes in various metabolic markers as a consequence of surgery and anaesthesia. D. Dalgleish St Helier, Jersey JE2 3XG, UK References 1 Kehlet H, Brandt MR, Hansen AP, Alberti KG. Effects of epidural analgesia on metabolic profiles during and after surgery. British Journal of Surgery 1979; 66: 543±6. 2 Namba Y, Smith JB, Fox GS, Chalis JR. Plasma cortisol concentrations during Caesarean section. British Journal of Anaesthesia 1980; 52: 1027±32. 3 Barker JP, Robinson PN, Vafidis GC, Hart GR, Sapsed-Byrne S, Hall GM. Local anaesthesia prevents the cortisol and glycaemic response to cataract surgery. British Journal of Anaesthesia 1990; 64: 442±5. 4 Barker JP, Robinson PN, Burrin JM, Hall GM. Retrobulbar block fails to prevent an increase in serum cortisol concentration on emergence from anaesthesia after cataract surgery. British Journal of Anaesthesia 1994; 72: 119±21.

A reply

We are grateful for the opportunity to respond to Dr Dalgleish's letter. We are also aware of the effects of anaesthesia on the stress response. The purpose of the study was to evaluate the effects of surgical technique on stress hormones intra-operatively. In order to achieve

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our goal we used a standardised anaesthesia technique in both study groups while several conflicting reports about the effects of general anaesthetics on neuroendocrine response exists [1, 2]. In our anaesthetic technique the dose of morphine used during induction is not enough to suppress the stress response and no regional anaesthetic technique was applied [3]. Induction, intubation and emergence affect the stress response during general anaesthesia. In this study blood samples were withdrawn 5 min after induction and intubation (the word intubation was not stressed in the manuscript and might have caused misunderstanding) when atracurium, morphine and isoflurane were on board for at least 5 min in both groups. The effects of intubation and induction were included on TO measurements. The samples were withdrawn at the end of the surgery prior to extubation Tend, excluding the effects of extubation. When one parameter is kept constant the outcome depends mostly on other factors, in this case the surgical technique. Cortisol was the main parameter in the referred literature in Dr Dalgleish's letter [4] that may increase intra-operatively regardless of anaesthetic technique [5]. In this study cortisol was not the only parameter followed; epinephrine, insulin, glucose, prolactin and interleukin 6 (where there is a sole parameter for tissue trauma) levels were also measured. The overall evaluation of these parameters proves the similarity between groups. Nevertheless, we would like to thank Dr Dalgleish for pointing out the effects of general anaesthesia on the stress response. The effects of laparoscopy on the stress response are published both in anaesthesia and surgery journals and include contributions by anaesthetists and surgeons [6±9]. We are currently running the same study, both intra-operatively and postoperatively, on patients after parental approval. Acetaminophen 20 mg.kg21 PR every 6 h is used for postoperative pain relief. Blood samples are being taken after 12 h and 24 h postoperatively. The results from eight patients (n 4 open appendicectomy, n 4 laparoscopic appendicectomy) reveal a

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similar trend intra- and postoperatively in both groups. The glucose, prolactin and cortisol levels are depressed after 12 h and return to control values at 24 h. As anaesthetists, we have to keep in mind that laparoscopic interventions in children have similar neuroendocrine response and have to consider the use of techniques that can also abolish the stress response during laparoscopic surgery. P. Bozkurt Istanbul University Cerrahpasa Medical Faculty, 34303 Istanbul, Turkey

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References Carli F, Ronzoni G, Webster J, Khan K, Elia M. The independent metabolic effects of halothane and isoflurane anesthesia. Acta Anaesthesiologica Scandinavica 1993; 37: 672±8. Furuya K, Shimizu R, Hirabayashi Y, Ishii R, Fukuda H. Stress hormone responses to major intra-abdominal surgery during and immediately after sevoflurane- nitrous oxide anaesthesia in elderly patients. Canadian Journal of Anaesthesia 1993; 140: 435±9. Hall GM, Ali W. The stress response and its modification by regional anaesthesia. Regional Anaesthesia 1998; 53 (S2): 10±2. Barker JP, Robinson PN, Burrin JM, Hall GM. Retrobulbar block fails to prevent an increase in serum cortisol concentration on emergence from anaesthesia after cataract surgery. British Journal of Anaesthesia 1994; 72: 119±21. Aono H, Takeda A, Tarver SD, Goto H-. Stress responses in three different anesthetic techniques for carbon dioxide laparoscopic cholecystectomy. Journal of Clinical Anesthesia 1998; 10: 546±50. Myre K, Rostrup M, Buanes T, Stockland O. Plasma catecholamine and hemodynamic changes during pneumoperitoneum. Acta Anaesthesiologica Scandinavica 1998; 42: 343±7. Kristiansson M, Saraste L, Soop M, Sundqvist KG, ThoÈrne A. Diminished interleukin-6 and C-reactive protein responses to laparoscopic versus open

cholecystectomy. Acta Anaesthesiologica Scandinavica 1999; 43: 146±52. 8 Engin A, Bozkurt B, Ersoy E, Oguz M, GoÈkcËora N. Stress hyperglycemia in minimally invasive surgery. Surgical Laparoscopy and Endoscopy 1998; 18: 435±7. 9 Goodale R, Beebe D, McNevin MP, Boyle M, Letourneau JG, Abrams J, Cerra B. Hemodynamic, respiratory, and metabolic effects of laparoscopic cholecystectomy. American Journal of Surgery 1993; 166: 533±7.

A simple method of sub-Tenon anaesthesia delivery

In ocular regional anaesthesia today, the sub-Tenon/parabulbar technique is gaining popularity [1]. The fear of sharp needle complications during retrobulbar or peribulbar injections including perforation of the globe, subarachnoid injection, retrobulbar haemorrhage [2] and respiratory complications [3] are leading many anaesthetists towards this blunt cannulae local anaesthetic delivery technique. Although most published studies refer to Stevens' method [4], other methods are in use, which include Greenbaum [5] and Fukasaku [6]. These techniques involve gaining access to sub-Tenon's space by incising the conjunctiva and tenon's capsule 3±5 mm away from the limbus and subsequent lifting of the capsule which allows the introduction of a blunt cannula and subsequent injection of local anaesthetic agent; but where they differ is in the quadrant of access and the nature of the cannula. We use a commercially available subTenon curved metal cannula but during a brief period the metal cannula was not available in our unit. The design of this cannula led us to think if local anaesthetic can be delivered by an alternative method by introducing a readily available intravenous plastic cannula sheath without the introducer. The technique is essentially similar to Stevens' technique [4]. The incision is made 3±5 mm away from the limbus in the inferonasal compartment. A 20G uncut intravenous cannula (Fig. 8) is mounted on a 5-ml



Figure 8 Intravenous cannula with syringe in sub-Tenon's space.

syringe filled with the local anaesthetic of choice and is introduced through the incised area and the desired amount of local anaesthetic is injected. We have successfully used this method of local anaesthetic delivery through subTenon's space with good results and without problems. The intravenous plastic cannulae are readily available in all hospitals. These are cheaper, £0.40± 0.60 in comparison with commercially available metal cannulae, £2±4. Smaller gauges, e.g. 20±22, are suitable in length but are prone to kinking in the space. On the other hand, higher gauges, e.g. 16±18, are tougher but are longer in length. We suggest that this method of subTenon anaesthesia delivery is a simple, readily available, cheap, safe and effective alternative to commercial cannulae if not available. C. M. Kumar S. Williamson R. Chabria South Cleveland Hospital, Middlesborough TS4 3BW, UK References 1 McLure HA, Rubin AP. Local anaesthesia for ophthalmic surgery. Current Anaesthesia and Intensive Care 1999; 10: 40±7. 2 Rubin AP. Complications of local anaesthesia for ophthalmic surgery. British Journal of Anaesthesia 1995; 75: 93±6. 3 Kumar CM, Lawler PG. Pulmonary oedema following peribulbar block.


British Journal of Anaesthesia 1999; 82: 777±9. 4 Stevens JD. A new local anaesthesia technique for cataract extraction by one quadrant sub-Tenon's infiltration. British Journal of Ophthalmology 1992; 76: 66±8. 5 Greenbaum S. Parabulbar anesthesia. American Journal of Ophthalmology 1992; 114: 776. 6 Fukasaku H, Marron J. Pinpoint anaesthesia: a new approach to local ocular anaesthesia. Journal of Cataract Refract Surgery 1994; 20: 468±71.

Epidural insertion under general anaesthesia

Pursuing the discussion about àsleep' vs. àwake' for the insertion of epidural catheters (Anaesthesia 2000; 55: 288±90) there are a few further arguments to support the àwake' proponents. 1 Anaesthetists, like surgeons, act more gently and circumspectly in using any technique when the patient is awake. This is always to the patient's benefit. 2 Keeping a patient awake requires that the patient has a detailed explanation of the epidural procedure beforehand, and this helps to commit the anaesthetist to a very clear decision about the risk/ benefit ratio. 3 The sitting position is available where the anatomy may be difficult, e.g. the obese patient. 4 There will be less back strain for the anaesthetist and anaesthetist's assistants

when the patient is able to turn him/ herself at the end of the procedure. No procedure is without risk of complication. The incidence of complications is so low that we will wait a long time for definitive evidence to support the much awaited guideline proposals from the European Society of Regional Anaesthesia. Meanwhile careful, wary technique remains the most important factor. Many young and restless patients will require general anaesthesia prior to epidural injection, but the majority can be well managed awake, especially if one includes in this definition the use of sedation by a small dose of intravenous benzodiazepine! M. J. Lindop Addenbrooke's Hospital, Cambridge, CB2 2QQ, UK Effectiveness of blood transfusion in Malawi

Having been very impressed by Dr Fenton's study on the effectiveness of blood transfusions for Caesarean section in Malawi (Anaesthesia 1999; 54: 1055± 8), I contacted him to discuss the results and enquire on specific concerns not answered in the original article. Dr Fenton was kind enough to share with me additional data and we would like to report further information on the effectiveness of blood transfusions in this context. The results reported originally are especially significant since they help resolve a crucial issue on which very little data are available, i.e. the effectiveness of allogeneic red cells to reduce mortality in haemorrhagic shock. However, from the original report in Anaesthesia, it was not possible to determine the proportion of mothers who survived/died while transfused or not in the Central vs. District areas. This may be important since transfusion practice appears to be quite different from one area of the country to another. Six thousand nine hundred and nine (6909) patients are now included in the database. Of these, 840 were deemed to require a transfusion and 558 were effectively transfused while 282 were

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not, owing to blood availability. Of the transfused mothers, 33 died (5.9%) and, of those who could not be transfused, 22 died (7.8%; p 0.369 by Chisquared). Thus, overall, transfusion of red cells does not appear to decrease mortality, as suggested in the original publication. However, the situation is very different in diverse parts of the country. Blood is more readily available in the District but much less readily available in the Central Hospital. In the District, 591 of the 4422 mothers (13.4%) were deemed to require blood and 432 (73%) were transfused. Of the transfused mothers, 25 died (5.8%) and, of those who could not be transfused, 18 died (11.3%), a statistically significant difference (p 0.034 by Chi-squared). Hence, in the District, blood transfusion appeared to save lives, as we have been taught to expect. In the Central Hospital, 249 of the 2487 mothers (10%) were deemed to require blood and 126 (51%) were transfused. Of the transfused mothers, eight died (6.3%) and, of those who could not be transfused, only four died (3.2%; p 0.399 by Chi-squared). Mortality in mothers deemed to require red blood cells, but not transfused, was lower in the Central Hospital compared with the District (3.2% vs. 11.3%, respectively; p 0.022). Thus, in the Central Hospital, not only does blood transfusion not save lives, but it appears to worsen outcome. How can we explain this apparent paradox? As stated originally, fluid therapy is also very different in diverse parts of the country. Volume replacement with nonblood fluids is aggressive in the Central Hospital while the slow transfusion of blood is often the only volume administered in the District. The additional data presented here suggest that, globally, volume replacement is more important than red cell transfusion in mothers with anaemia or shock after Caesarean section. In mothers appropriately volume resuscitated, transfusions appear to be deleterious, a situation similar to that observed in industrialised countries where the benefits of transfusions are not as apparent as once thought [1]. These results are not those of a

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randomised clinical trial, but we must attempt to learn the most from the difficult African medical situation. Dr Fenton's observations are important for all of us, but particularly in Africa where blood may not always be readily available for fluid resuscitation and where, in parts of the continent, the safety of blood products is problematic (the incidence of endemic HIV may be as high as 20% [2±5]). In this context, we encourage aggressive nonblood fluid therapy for initial volume resuscitation. Erythrocyte transfusions should be considered later and only when specific indications for their administration exist. J-F. Hardy University of Montreal, QueÂbec, Canada P. M. Fenton College of Medicine, Malawi References 1 Hebert PC, Wells G, Blajchman MA, et al. A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group. New England Journal of Medicine 1999; 340: 409± 17. 2 Lackritz EM, Campbell CC, Ruebush T, et al. Effect of blood transfusion on survival among children in a Kenyan hospital. Lancet 1992; 340: 524±8. 3 Lackritz EM, Ruebush T Kd, Zucker JR, Adungosi JE, Were JB, Campbell CC. Blood transfusion practices and blood-banking services in a Kenyan hospital. Aids 1993; 7: 995±9. 4 Zucker JR, Lackritz EM, Ruebush TK, et al. Anaemia, blood transfusion practices, HIV and mortality among women of reproductive age in western Kenya. Transaction of the Royal Society of Tropical Medicine and Hygiene 1994; 88: 173±6. 5 Obonyo CO, Steyerberg EW, Oloo AJ, Habbema JD. Blood transfusions for severe malaria-related anemia in Africa: a decision analysis. American Journal of Tropical Medicine and Hygiene 1998; 59: 808±12.

Blood transfusion for Caesarean section

We read with interest the article by Fenton (Anaesthesia 1999; 54: 1055±8) looking at blood transfusion for Caesarean section in Malawi. We recently conducted a retrospective audit (a little nearer home) looking at blood transfusion in women who had undergone Caesarean section in our hospital during a 12-month period (September 1998 to August 1999). Of the 557 Caesarean sections performed in this period, only 36 patients had received a blood transfusion (6.5%). Only 9% of the 1123 cross-matched units were used. Nine patients were transfused intra-operatively whilst 12 patients received blood between 4 h and 4 days postoperatively. The mean (SD) haemoglobin level of those patients transfused more than 8 h after surgery was 7.2 (1.6) g.dl21. As a result of the audit, we are currently negotiating changing a long tradition of practice in our hospital. Until now, it has been customary to provide two units of cross-matched blood in theatre at the time of surgery. The evidence suggests that this is both unnecessary and extremely wasteful of time and money. The current opinion is that an excessive number of units are being cross-matched if the cross-match to transfusion ratio is more than 2 : 1. The ratio for Caesarean sections in our hospital was 11 : 1! In addition, for operations in which less than 10% of patients require blood, a `group and screen' policy is appropriate [1]. As Fenton rightly states, mothers (and patients in general) die more commonly from uncorrected hypovolaemia than from actual anaemia. Young patients can tolerate chronic and even acute anaemia well, providing the circulating volume is maintained, and should not be exposed to blood transfusion without careful thought. Peri-operative blood transfusion has also been associated with increased postoperative bacterial infection. There is a lack of evidence to support the use of `top-up' transfusions, particularly in healthy, well-nourished individuals. Although the risks from blood transfusion are small, the majority of



well-informed individuals must surely prefer a short course of oral iron supplements. This is a perfectly adequate and safe alternative. Although probably behind the times in that most hospitals have already stopped routinely cross-matching blood for all Caesarean sections, this audit has highlighted the considerable waste that is occurring in the blood transfusion industry. The hospital transfusion committee has now decided to audit all departments in the Trust, starting with orthopaedic surgery, to review the current use and abuse of the blood transfusion service. This is long overdue but may lead to the establishment of local policies for the crossmatch and transfusion of blood. J. M. Cupitt L. P. Raghavendra Blackpool Victoria Hospital, Blackpool FY3 8NR, UK Reference 1 Contreras M, ed. ABC of Transfusion, 3rd edn. BMJ Books, 1998.

Identification of epidural space using air with normal saline

Identification of the epidural space has been achieved by a number of techniques, of which loss of resistance to air or saline is the most commonly used. Some anaesthetists prefer air while others advocate using normal saline [1]. Whereas no serious adverse effects have been associated with the use of saline, there are a number of case reports describing complications associated with the use of air for identification of the epidural space [2]. The list of complications includes venous air embolism, pneumocephalus and patchy distribution of epidural block [2]. Despite this, a large number of anaesthetists including ourselves have been continuing to use air for identifying the epidural space. A recent survey showed that more than 30% of obstetric anaesthetists in Britain preferred air to normal saline [3]. The superior quality of the `feel' that one gets throughout the


insertion of the Tuohy needle is the reason why we prefer using air. Recently, we devised a new approach using both air and normal saline together. We use a combination of three-way taps connected together between the Tuohy needle and the loss of resistance syringe (Fig. 9). The side ports of these three-way taps are connected using a short length of extension tubing forming a vertical loop. The three-way taps are then turned so that they communicate with each other through the extension tubing connected to their side ports. Normal saline is drawn up through the Tuohy needle connected to this assembly. Thus, the dead space of the needle and the descending limb of the loop formed by the extension tubing contain normal saline. The syringe and the ascending limb, on the other hand, contain only air. The three-way taps are locked, the tip of the Tuohy needle inserted into the lumbar intervertebral space selected and at a depth of 2 cm the three-way taps are unlocked. The needle is advanced feeling the resistance to the column of air in the syringe and the ascending limb of the loop. On entering the epidural space, however, it is the normal saline from the descending

limb of the loop that is injected first and not the air. Using this technique, we experience the same quality of resistance that is usually felt using air. An extension tubing with two male ends can be used to connect the threeway taps. We constructed our own as shown in the figure. The dead space of the descending limb should be 2±4 ml as this is the volume that tends to get injected at loss of resistance. The whole assembly must be tested for leaks before beginning the procedure. S. S. Kale S. A. Oosthuysen James Paget Hospital, Great Yarmouth N31 6LA, UK. References 1 Scott DB. Identification of epidural space: loss of resistance to air or saline? Regional Anaesthesia 1997; 22: 1±2. 2 Saberski LR, Kondamuri S, Osinubi OY. Identification of the epidural space: is loss of resistance a safe technique? A review of the complications related to the use of air. Regional Anaesthesia 1997; 22: 3±15. 3 Howell TK, Prosser DP, Harmer M. A change in resistance? A survey of

Figure 9 Arrangement of three-way taps and tubing attached to Tuohy needle and loss of

resistance syringe. Note that for the purpose of illustration an opaque liquid has been used in place of saline.

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epidural practice amongst obstetric anaesthetists. Anaesthesia 1998; 53: 238±43.

A method of administering topical anaesthesia for flexible airway endoscopy

We have found that a modified epidural catheter inserted through the suction port of the fibreoptic endoscope is an effective method of accurately introducing local anaesthetic drugs to provide topical anaesthesia for flexible airway endoscopy. The distal end of a 16-gauge epidural catheter is cut to remove the side holes and is then threaded through the suction port of an endoscope (in our practice we use an Olympus LF-2). It is advanced until the cut end of the epidural catheter is flush with the distal end of the endoscope. The proximal end of the catheter is then attached to its connector in the usual manner and this is in turn attached to two threeway taps arranged in series. A 1-ml syringe containing local anaesthetic is fitted to the side port of the distal three-way tap via a nonreturn valve. The side port of the proximal threeway tap is left open to air and a 2-ml syringe is attached to the other port via a nonreturn valve. The plunger of the 2-ml syringe is removed and replaced with a length of oxygen tubing connected to an oxygen supply at a flow of 1 l.min21 (Fig. 10). Local anaesthetic solution is delivered to the airway via the endoscope with the help of an assistant who occludes the open port of the proximal three-way tap whilst simultaneously injecting 0.1±0.2ml aliquots of local anaesthetic via the port of the other three-way tap (Fig. 11). A 1-ml syringe is needed to overcome the high pressure generated by the gas flow. Injection produces a fine jet of local anaesthetic, which can be precisely targeted at areas of mucosa at up to 5 cm distance from the tip of the endoscope. The direction of spray of local anaesthetic is controlled by movement of the tip of the fibreoptic endoscope. This allows the airway ahead of the

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Figure 10

advancing endoscope to be accurately anaesthetised under direct vision. This technique is more time consuming than the usual spray-as-you-go method but the fine spray produces less coughing and gagging. We find this device most useful for producing airway anaesthesia if coughing has to be minimised or if sedation is contraindicated, thus placing strenuous

demands on the local anaesthetic technique. D. O'Hare R. Harwood N. Woodall G. Barker Norfolk and Norwich Hospital, Norwich NR1 3SR, UK

Figure 11



Even simpler remifentanil infusions

A simple way to calculate remifentanil dosage (by dividing 3333 by body weight (BW) in kg to give the volume of dilutant for 2 mg) has been described by Cort and Parsloe (Anaesthesia 2000; 55: 90). An even simpler method using a standard dilution is given here. 2 mg remifentanil is dissolved in 40 ml dilutant, giving a concentration of 50 mg.ml21. 0.5 BW in kg infusion rate in ml.h21 25 mg.kg21.h2l 25/60 mg. kg21.min2l 0.416 mg.kg21.min21. Thus half the patient's BW given as ml.h21 means the patient is receiving 0.4 mg.kg21.min2l, e.g. 60 kg patient 30 ml.h21 0.4 mg.kg21.min21. This works for any weight. From this it is easy to calculate smaller or larger doses by further halving, quartering or doubling the infusion rate. Arithmetical errors are less likely as dilution volumes do not have to worked out with a calculator. (My mental arithmetic is not always up to dividing 3333 by BW, and it is easy to get the decimal point wrong.) Mistakes are also less likely with a standard dilution. The concentration is the same as fentanyl (50 mg.ml21), so is already familiar to the anaesthetist, and the bolus dose is readily worked out. This may be more appropriate for surgery with faster turnover than cardiac surgery. The patient's weight may not always be known before arrival in theatre, and using a standard dilution the drug can be prepared in advance. Accuracy to fractions of ml is less essential for a drug with a very short half-life such as remifentanil. It is easy to titrate to clinical need and physiological parameters, and the dose range of remifentanil is very wide in any case (0.05±2 mg.kg21.min2l). This method goes some way to making remifentanil more user friendly. J. Millar John Radcliffe Hospital, Oxford OX3 9DU, UK


Lessons from history

The early use of volatile anaesthetic agents in the treatment of acute asthma is effective but its use is not without potential pitfalls [1]. A 40-year-old man presented to the Accident & Emergency Department with severe asthma. He had not attended hospital or his general practitioner for 8 years and his case notes were not immediately available. His asthma was so severe that he was unable to speak and his wife provided the history to the casualty staff. This included the fact that treatment of a previous attack with aminophylline had caused cardiac arrhythmias. He was treated therefore with nebulised salbutamol and sodium cromoglycate, intravenous salbutamol and corticosteroids and was admitted to the Intensive Care Unit. The administration of a subanaesthetic dose of sevoflurane was considered. However, he began to respond to the initial treatment and it became possible to take a history and further examine him. When questioned about operations, he reported that he had biopsy-proven malignant hyperpyrexia. It was fortunate for both the patient and his attendants that a volatile anaesthetic agent or succinylcholine had not been administered. His wife had not thought to mention it, as his admission seemed unrelated to the potential administration of an anaesthetic. This case teaches two important lessons. The first is that a complete history is essential, whether seeing a patient pre-operatively or in the intensive care setting. The chance of an adult presenting for an anaesthetic procedure with malignant hyperpyrexia is approximately 1 : 40 000 [2] and with the incidence of asthma in the adult population being 8.5% [3], the combined risk of a patient suffering from both is in excess of 1 : 470 000. While clearly rare, the potential consequences should make an enquiry about malignant hyperpyrexia susceptibility an essential component of a medical history if exposure to trigger agents is likely. The Royal College of Anaesthetists [4] and the Association of Anaesthetists of

Great Britain and Ireland [5] publish guidelines for pre-operative assessment. Neither recommends direct enquiry regarding malignant hyperpyrexia susceptibility. The second lesson involves the value of the `Medic-Alert' bracelet. They are inexpensive and available from most pharmacies. This patient was not wearing one and it could potentially have cost him his life. S. J. Wimbush G. A. Morgan Royal Cornwall Hospital, Truro TR1 3LJ, UK References 1 Padkin AJ, Baigel G, Morgan GA. Halothane treatment of severe asthma to avoid mechanical ventilation. Anaesthesia 1997; 52: 994±7. 2 Dunn D. Malignant hyperthermia. AORN Journal 1997; 65: 728±31. 3 Anon. Oxford Textbook of Medicine, Vol. 2, Section 15, 75±6. Year? 4 Website. www.rcoa.ac.uk. 5 Website. www.aagbi.org.

Facial hair, sex and facemasks

Dr McLure and colleagues have elegantly demonstrated that facemask `wiggling' increases downward dispersal of bacteria, but being a clean-shaven male had a protective effect in this respect (Anaesthesia 2000; 55: 173±6). I sincerely hope that this will not lead to the exclusion of female or bearded anaesthetists from delivery suites. In our unit we require that both the anaesthetist and their assistant wear freshly donned facemasks during regional anaesthetic procedures (in addition to caps and, in the case of the anaesthetist, gown and gloves). If the parturient adopts the sitting position for the procedure, she is also requested to cover her hair. Since these precautions have been followed we have had no infective complications despite the fact that our anaesthetists are encouraged to maintain continuous verbal communication with their patients (entailing mask `wiggling'). The advice of these authors in a previous paper, that the

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head should be turned away during speech (Anaesthesia 1998; 53: 624±6), would thus considerably slow down procedures ± a potential hazard particularly in the labouring patient. I agree with the authors that a good aseptic technique is of prime importance and would like to see more detailed descriptions of this in reports of infective complications. F. S. Plaat Queen Charlottes & Chelsea Hospital, London W6 0XG, UK British syringe label `standards' are an accident waiting to happen

We agree with Dr Radhakrishna that a consistent colour standard is required for user-applied syringe labels (Anaesthesia 1999; 54: 963±8). Colour is a powerful psychological cue [1±3], which can facilitate the identification of drugs. Some have argued that the use of colour reduces the likelihood that the label will be read. It should be emphasised that colour used correctly is a supplement to, rather than a substitute for, this important task. If colour coding is applied by class of drug, the label must still be read in order to identify the specific drug within the class. The use of more than one type of cognitive cue (colour and text) provides multiple opportunities to trap potential errors before they occur. Such an approach is consistent with the safety principles of complex-systems theory developed in the nuclear and aviation industries ± an approach which anaesthesia is increasingly adopting in an effort to avoid anaesthetic error and iatrogenic harm [4±7]. However, if colour is to be used, a consistent colour standard for drugs is very important. The situation described by Radhakrishna in Britain, with contradictory label systems used in different hospitals and even within the same hospital, is clearly an accident waiting to happen. Faults like these in organisations are called latent errors and we know from an extensive literature in other fields that their existence guarantees

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that it will only be a matter of time until errors are made because of them [2±8]. In fact, it is very likely that such errors have already happened. As Radhakrishna states, consistent colour-code standards already exist in Australia, New Zealand and the USA [9, 10], and all of these use the same set of colours for drug classes. An identical colour standard also exists in Canada [11]. However, it seems that the colours used in Britain differ from the colour standards used in these countries. This creates a further problem for overseas anaesthetists coming to work in Britain and for British anaesthetists working overseas. Radhakrishna suggests that it may take sometime before a consistent colour standard can be adopted in Britain and that in the interim British anaesthetists should stop using colour as a cue in syringe identification. This seems counter-productive, however, as the use of colour is currently widespread in Britain and can be a valuable aid to safety. The simplest solution would be for Britain to adopt the colour standard used in the above mentioned countries. The transition involved in the adoption of any internationally consistent standard may carry logistical difficulties and some risk. With respect to user-applied syringe labels, however, the safety benefits would be considerable while the risk is likely to be no more than continuing with the status quo. We suggest that the best approach would be for anaesthetists to move to a consistent British standard as soon as possible. C. S. Webster A. F. Merry Green Lane Hospital, Auckland, New Zealand References 1 Merry AF, Webster CS. Labelling and drug administration error. Anaesthesia 1996; 51: 987±8. 2 Reason J. Human Error. New York: Cambridge University Press, 1990. 3 Perrow C. Normal Accidents: Living with High-Risk Technologies. New York: Basic Books, 1984.

4 Galletly DC, Mushet NN. Anaesthesia system errors. Anaesthesia and Intensive Care 1991; 19: 66±73. 5 Runciman WB, Webb RK, Lee R, Holland R. System failure: an analysis of 2000 incident reports. Anaesthesia and Intensive Care 1993; 21: 684±95. 6 Gaba DM, Maxwell M, DeAnda A. Anesthetic mishaps: breaking the chain of accident evolution. Anesthesiology 1987; 66: 670±6. 7 Webster CS, Merry AF, Larsson L, McGrath M. A complex-systems approach to safer drug administration in anaesthesia. Journal of Clinical Monitoring and Computing (abstract; currently available from http:// www.scata.org.uk/articles/abstract/ autumn99.html). 8 Reason J. The contribution of latent human failures to the breakdown of complex systems. Philosophical Transactions of the Royal Society of London, Series B 1990; 327: 475±84. 9 Anon. User-applied labels for use on syringes containing drugs used during anaesthesia (AS/NZS 4375. 1996). Wellington: Standards New Zealand, 1996. 10 Anon. Standard specification for user applied drug labels in anesthesiology (D4774±94). Philadelphia: American Society for Testing and Materials, 1995. 11 Anon. Standard for user-applied drug labels in anaesthesia and critical care (Z264.3±98). Etobicoke. Ontario: Canadian Standards Association, 1998.

Paradoxical emboli in patent foramen ovale

A 77-year-old man who was scheduled for a total hip replacement was referred to me for a pre-operative anaesthetic assessment because he had had a pacemaker inserted for complete heart block two years previously. The cardiologist who implanted the pacemaker had echocardiographically diagnosed a 1-cm ostium secundum atrial septal defect with left to right shunting. I was concerned that during the reaming and cementation of the femoral shaft, emboli of air, fat or other debris released



into the venous system could, if the shunt was reversed, produce paradoxical emboli in the heart, brain and kidneys and other organs. Pell et al. have graphically demonstrated such a possibility occurring when using transoesophageal echocardiography during a total hip replacement [1]. Echogenic material was seen entering the right side of the heart, and as right heart and pulmonary artery pressures increased, as well as the pulmonary vascular resistance in response to multiple episodes of pulmonary embolisation, the shunt reversed and the echogenic material passed through the foramen ovale into the left side of the heart with disastrous consequences for the patient. As the operation was elective, my patient was referred for cardiological opinion. Operative device closure of the ASD before hip replacement was advised. The foramen ovale is patent in 20± 34% of people [2]. Obviously many patients with unrecognised ASD have undergone joint replacement uneventfully. If, however, an ASD is demonstrated before surgery, should such measures as button closure of the defect be routinely undertaken preoperatively? W. O. Roberts Ysbyty Gwynedd, Bangor LL57 2PW, UK References 1 Pell ACH, Hughes D, Keating J, Christie J, Busitil A, Sutherland GR. Fulminating fat embolism caused by paradoxical embolism through a patent


foramen ovale. New England Journal of Medicine 1993; 329: 926±9. 2 Hagen PT, Scholz DG, Edwards WD. Incidence and size of patent foramen ovale during the first 10 decades of life: an autopsy study of 965 normal hearts. Mayo Clinic Proceedings 1984; 59: 17±20.

How to skin a bearded cat

We note with interest the response to our original letter (Anaesthesia 1998; 53: 1034±5), in which we described the use of cling film to rescue the bearded airway. There were concerns expressed over the safety of our suggestion [1, 2] and we agree with many of these issues. Mummification of the patient with cling film is not, however, what we described or suggested. The cling film should be applied so that it covers the patient's face and not the neck. It is then still possible to apply cricoid pressure and avoid venous occlusion. At the time of laryngoscopy the cellophane can be split free and therefore mandibular subluxation is not compromised. There were also concerns that the time spent applying the cling film would lead to hypoxia [2]. The situation was that of a difficult airway when adequate oxygenation could not be achieved. Time spent trimming the patients beard might not be any shorter. Obviously, in-line cervical spine immobilisation should always be applied in the trauma situation and we would not recommend the use of cling film when the stability of the cervical spine is in doubt. The unconscious trauma victim described in our original letter was a

burns patient and cervical spine injury, from the history, was not an issue. In the responses several alternative suggestions were made on how to manage the bearded airway. These included a defibrillator pad with a hole cut in the centre [2, 3]; a laryngeal mask [2, 4]; the eversion of the lower lip on which to place the face mask rim [5]; a rapid sequence induction [2]; and finally the impromptu beard trimming [1] (assuming an NHS razor is both sharp and available and that there is time enough for a shave). Finally, we reported this following a single episode and accept that it doesn't bear medical scrutiny. It may be useful in a situation involving a bearded patient who would prefer his or her whiskers left intact. Nevertheless, we accept that cling film should appear at the bottom of the list of intervention measures but there is more than one way to skin a cat. To this end we have recruited a willing feline and a brand new role of cling film. W. Ames University of Michigan Medical Center, MI 48109±0048, USA References 1 Moore EW, Cowan CM. A close shave. Anaesthesia 1999; 54: 305. 2 Hancock AC. The bearded airway. Anaesthesia 1999; 54: 408. 3 Thomas DI. Overcoming the beard. Anaesthesia 1999; 54: 100. 4 Alexander R. Overcoming the beard. Anaesthesia 1999; 54: 100. 5 Crooke J. The bearded airway. Anaesthesia 1999; 54: 500.

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