Airway management for tonsillectomy
1 Manchester, UK
2 Preston, UK
* E-mail: alexandra.roper{at}btinternet.com
Editor—We read with interest the article1 on airway management for tonsillectomy, which concluded that there is widespread non-compliance in the use of disposable anaesthetic instruments. The authors quite correctly make the point that currently non-disposable surgical instruments are used. Surely, prion transmission is less likely to occur via anaesthetic than surgical instruments which are intrinsically contaminated with tissue. The current RCoA guidelines recommend the use of single-use instruments for anaesthesia in tonsillectomy, although reusable instruments are used for the actual operation. We feel that, before enforcing guidelines that have not been complied with nationally, a full assessment of whether the risk of prion transmission is clinically significant is necessary.
In 2001, the Department of Health recommended that although there was no evidence of any patient being infected with variant Creutzfeldt–Jakob disease (CJD), precautions should be taken to reduce the ‘theoretical risk’. The use of single-use surgical instruments was abandoned after an increased risk of haemorrhage was identified by the National Prospective Tonsillectomy Audit (NPTA).2 Frosh3 recommended improved decontamination and the use of disposable surgical instruments, before the results of the NPTA. Improved decontamination should reduce the risk of CJD transmission and can be applied to both surgical and anaesthetic instruments. This also resolves the problem of substandard single-use instruments, as identified by the authors. It cannot be consistent to have one rule for surgeons and another rule for anaesthetists.
Bath, UK
* E-mail: timcook007{at}googlemail.com
Editor—I am grateful for Miss Roper and Dr Laha's interest in our article.1 They ask for a ‘full assessment of whether the risk of prion transmission is clinically significant’. I understand that the Royal College of Anaesthetists and Association of Anaesthetists of Great Britain and Ireland (AAGBI) are both in the process of performing such an assessment, before updating the College advice and the AAGBI document ‘Infection and the Anaesthetist’.
They refer to the possibility of improved decontamination. This is pertinent to anaesthetic practice: several studies have shown that treatment with potassium permanganate 0.4–0.8% improves decontamination of both reusable silicone laryngeal masks and metal and rubber airway equipment.4 5 The stronger concentration appears to eliminate residual protein. This is a non-standard treatment but probably merits further exploration for its role in ‘risk reduction’.
The authors close their letter with the statement ‘It cannot be consistent to have one rule for surgeons and another rule for anaesthetists’. If, by that they imply that surgeons and anaesthetists should automatically either both use single-use equipment or both use reusable equipment, I do not agree. In November 2006, the National Institute for Health and Clinical Excellence (NICE) published their report ‘Patient safety and reduction of risk of transmission of CJD via interventional procedures’.6 This document makes much of risk–benefit analysis but also cost–benefit analysis. The conclusion that tonsillectomy does not require single-use surgical equipment (and that some neurosurgery does) appears to be based both on the intermediate risk of tonsillectomy and the high cost of single-use surgical equipment: in essence, it is mostly a cost–benefit decision. The document makes almost no mention of anaesthesia. Laryngoscopes are mentioned only ‘in passing’ and laryngeal masks are not mentioned at all. The document therefore makes no specific recommendations relevant to anaesthesia. For anaesthesia, the risks of both use of, and avoidance of, reusable equipment are different from surgery. However, the benefits and costs also differ. For instance, the costs of substituting in single-use equipment for anaesthesia are small compared with surgery. Therefore, the result of a cost–benefit analysis for anaesthesia cannot be inferred from the result of the surgical assessment and indeed the solution may be different. Unfortunately, this analysis was not performed for anaesthesia.
What is needed, I quite agree, is a clearer statement of what the risk of transmission of vCJD is as a result of anaesthetic practices. If this is available, it will allow the College and Association to arrive at clearer advice that is more likely to be accepted and followed.
The author was paid by Intavent Orthofix and the LMA-company for lecturing. They also paid for the postage costs of this survey. They were otherwise uninvolved.
References
1 Clarke MB, Forster P, Cook TM. Airway management of tonsillectomy: a national survey of UK practice. Br J Anaesth (2007) 99:425–8.
2 National Prospective Tonsillectomy Audit. (2005) 5. British Association of Otolaryngologists, Head and Neck Surgeons Comparative Audit Group, Clinical Effectiveness Unit, Royal College of Surgeons of England.
3 Frosh A. Iatrogenic vCJD from surgical instruments. Br Med J (2001) 322:1558–9.
4 Laupu W, Brimacombe J. Potassium permanganate reduces protein contamination of reusable laryngeal mask airways. Anesth Analg (2004) 99:614–6.
5 Laupu W, Brimacombe J. The effect of high concentration potassium permanganate on protein contamination from metallic and synthetic rubber airway equipment. Anaesthesia (2007) 62:824–6.[CrossRef][Web of Science][Medline]
6 Patient safety and reduction of risk of transmission of Creutzfeldt–Jakob disease (CJD) via interventional procedures. Interventional procedure guidance 196. (2006) London: National Institute for Health and Clinical Excellence.
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