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Correspondence

Definition of difficult tracheal intubation

Souvatzis, X.*; Askitopoulou, H.*

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European Journal of Anaesthesiology: August 2008 - Volume 25 - Issue 8 - p 694-695
doi: 10.1017/S026502150800416X

EDITOR:

We read with interest the article by Yildiz and colleagues [1] 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' [1]. That definition belongs to the 1993 ASA guidelines [2]. 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) [4]. A recent study confirmed that the rate of complications was directly related to the number of laryngoscopic attempts during emergency airway management [5]. The risk of airway and even haemodynamic complications increased with the second laryngoscopic attempt and rapidly accelerated with three or more attempts [5]. In particular, the third intubation attempt during airway manipulation was found to be a risk factor contributing to cardiac arrest [6]. 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 [7]. 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.

References

1. Yildiz TS, Korkmaz F, Solak M et al. Prediction of difficult tracheal intubation in Turkish patients: a multi-center methodological study. Eur J Anaesth 2007; 24: 1034–1040.
2. Caplan RA, Benumof JL, Berry FA et al. Practice guidelines for management of the difficult airway. A report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology 1993; 78: 597–602.
3. American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Practice guidelines for management of the difficult airway. An updated report. Anesthesiology 2003; 95: 1269–1277.
4. Mort TC. Complications of emergency tracheal intubation: immediate airway-related consequences – Part II. J Intensive Care Med 2007; 22(3): 157–165.
5. Mort TC. Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesth Analg 2004; 99: 607–613.
6. Mort TC. Complications of emergency tracheal intubation: hemodynamic alterations – Part I. J Intensive Care Med 2007; 22(4): 208–215.
7. Peterson GN, Domino KB, Caplan RA, Posner KL, Lee LA, Cheney MD. Management of the Difficult Airway. A Closed Claims Analysis. Anesthesiology 2005; 103: 33–39.
© 2008 European Society of Anaesthesiology