Safety and jet ventilation
Villejuif, France
* E-mail: bourgain{at}igr.fr
Editor—Cook and Alexander1 confirm that the practice of jet ventilation may be dangerous when applied without control of the driving pressure and tracheal pressure. However, we would like first to point out that we are not the authors of the following sentence ‘caution against use of TTJV when ventilation from supraglottic or subglottic catheters can be used, as risk of iatrogenic injury is too high’.2 In fact, our opinion is the exact opposite: laryngeal surgery, and especially laryngeal endoscopy, is optimally performed under transtracheal high-frequency jet ventilation. The reason is, as stated by Cook and Alexander, ‘the main advantage of transtracheal techniques is that it provides the surgeon with operating conditions unhindered by anaesthetic equipment or the need for the surgeon to maintain ventilation’.1 In a nationwide survey on anaesthetic management of laryngeal laser surgery, Cozine and colleagues3 did not show any difference between jet ventilation and tracheal intubation, but demonstrated that rate of complications was directly related to the number of surgeries performed under jet ventilation each year. In other words, we do well what we do often! Most laryngeal invasive endoscopic procedures are planned and simply cannot be performed without adequate equipment, particularly a jet ventilator which automatically cuts off ventilation when end-expiratory pressure exceeds a preset level.
Finally, we want to stress that every anaesthetist should be comfortable with transtracheal ventilation/oxygenation since they may, one day, face a cannot ventilate, cannot intubate situation. Laryngeal surgery is thus the ideal field for training in inserting a transtracheal cannula, even more so as this technique offers perfect operative conditions in invasive ENT endoscopic surgery. Furthermore, we strongly agree that guidelines and regular training in this particular field would be most welcome.
Bath, UK
* E-mail: timcook007{at}googlemail.com
Editor—Many thanks to Dr Bourgain and colleagues for their interest in our article. First, we would like to apologize for mis-attributing the statement to the authors. The correct reference in our article1 was to 11 not 1 and it is not a direct quotation.4
We believe our survey provides sufficient evidence to raise concerns over the use of transtracheal ventilation using a high pressure source without control of airway pressure, but a survey lacking denominators cannot confirm or refute its lack of safety. In the absence of large randomized controlled trials comparing techniques, properly designed prospective cohort data collection may be sufficient. It is possible that the 4th National Audit Project of the Royal College of Anaesthetists5 which will, from September 2008, prospectively identify major airway complications throughout the UK, will provide such information.
What our survey does illustrate is that the reality in the UK is that in the majority of hospitals, transtracheal procedures can only be performed using manual techniques. Assuming these techniques are only used for laryngeal surgery, we conclude that only 15% of respondents performed transtracheal techniques electively and only 7% have access to high-frequency jet ventilation. We agree the manual technique is ‘suboptimal’. However, if our experience is typical, it is likely that financial pressures prevent purchase of the more expensive equipment and suboptimal techniques are likely to be the norm in the UK for some time to come.
As inferred in our paper, we agree that all anaesthetists should be familiar with transtracheal ventilation techniques. Our survey suggests, at least in the UK, that experience is unlikely to be achieved during elective ENT lists. Other solutions are necessary.
References
1 Cook TM, Alexander R. Major complications during anaesthesia for elective laryngeal surgery in the UK: a national survey of the use of high-pressure source ventilation. Br J Anaesth (2008) 101:266–72.
2 Bourgain JL, Desruennes E, Fischler M, Ravussin P. Transtracheal high frequency jet ventilation for endoscopic airway surgery: a multicentre study. Br J Anaesth (2001) 87:870–5.
3 Cozine K, Stone JG, Shulman S, Flaster ER. Ventilatory complications of carbon dioxide laser laryngeal surgery. J Clin Anesth (1991) 3:20–5.[CrossRef][Medline]
4 Patel A, Randhawa N, Semenov RA. Transtracheal high frequency jet ventilation and iatrogenic injury. Br J Anaesth (2002) 89:184.[CrossRef][Medline]
5 Available from http://www.rcoa.ac.uk/index.asp?PageID=1089 (accessed June 27, 2008).
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