To the Editor:—
Schaumann et al. are to be congratulated on their large and detailed study on cricothyroidotomy techniques.1However, the suggestion that their results favor the Seldinger technique as a method of inserting a surgical airway is misleading. The control technique used was inappropriate; the airways used were not comparable, and uncuffed narrow bore tubes may not be suitable as emergency airways. The clinical applicability of the study is therefore limited. The authors did not discuss these deficiencies in their article.
The results do not necessarily support the use of a Seldinger technique but rather demonstrate that their standard technique of cricothyroidotomy is more time consuming. Their standard technique is more complex than that originally described for elective situations:2It involves, in addition, both vertical and horizontal incisions and also use of both dilation and a tracheal hook. Other techniques have been developed for emergency situations. These include that of the Advanced Trauma Life Support course3and the rapid four-step technique.4Expert reviewers have recommended such techniques.5It may be possible to secure an airway in 32 s,4as opposed to 109 s with the Arndt aiway1or 137 s1or 114 s4for a standard technique. Although these techniques may have their own problems,4,6they have been shown to work in clinical practice.7–10Comparison of a Seldinger airway for emergency use with one of these techniques would have been more valid. Elective techniques have previously been used as a control in studies of a new emergency technique,5,11and this has been criticized.12,13
The study assessed only the Arndt airway. The Seldinger technique is used with other airway devices. The Arndt airway is an uncuffed device of 3 mm ID. Subjective ease and objective speed of insertion of the Arndt airway may be a consequence of its narrower diameter when compared with the control airway: 5 mm ID plus a cuff. This may also account for the differences in injuries to the larynx. It has been shown that larger airways require an increased force for insetion.14It would have been more appropriate to have used a Seldinger cricothyroidotomy airway with a diameter comparable to that of the tracheostomy tube used. When the Cook Melker airway was compared with a standard elective technique, there was no difference in time of insertion.15
Reoxygenation and ventilation of the patient must also be considered in the assessment of a novel airway device. Clearly, this is a limitation of cadaver studies. It is likely that the performance of uncuffed narrow bore tubes depends on the degree of upper airway obstruction.16Their use as emergency airways has been criticized.17–19
It would be have been more appropriate for the study to have compared the cuffed Cook Melker airway to a cuffed tracheostomy tube inserted with the rapid four-step technique.
Gartnavel Hospital, Glasgow, United Kingdom. email@example.com