EDITOR:
We read with interest the article by Yildiz and colleagues [Reference Yildiz, Korkmaz and Solak1] about the prediction of difficult tracheal intubation. In the paper, there is a point that needs clarification. The authors state that the ASA Task Force on Management of the Difficult Airway defines difficult tracheal intubation as follows: ‘when proper insertion of the tracheal tube with conventional laryngoscopy requires more than three attempts or more than 10 min’ [Reference Yildiz, Korkmaz and Solak1]. That definition belongs to the 1993 ASA guidelines [Reference Caplan, Benumof and Berry2]. In the 2003 updated report, the ASA Task Force has revised the old numerical definition and now defines difficult tracheal intubation simply as ‘requiring multiple attempts’ [3].
Repeated airway interventions may potentiate tissue trauma, bleeding and mucosal oedema and may transform an airway that can be ventilated to one that cannot (cannot ventilate, cannot intubate situation) [Reference Mort4]. A recent study confirmed that the rate of complications was directly related to the number of laryngoscopic attempts during emergency airway management [Reference Mort5]. The risk of airway and even haemodynamic complications increased with the second laryngoscopic attempt and rapidly accelerated with three or more attempts [Reference Mort5]. In particular, the third intubation attempt during airway manipulation was found to be a risk factor contributing to cardiac arrest [Reference Mort6]. The latest analysis of the ASA closed claims database for management of the difficult airway showed that persistent intubation attempts during airway emergencies were significantly associated with death or brain damage [Reference Peterson, Domino, Caplan, Posner, Lee and Cheney7]. In light of the complications associated with multiple laryngoscopy attempts, it seems advisable not always to proceed with three intubation attempts, but to limit the attempts to one or two under optimal conditions, before using a secondary airway plan. The evidence presented justifies the change by the ASA Task Force of their definition for a difficult tracheal intubation and the abolition of the three attempts as a cut-off.
