Clarifying the indications for difficult airway alert forms

We read with interest the letter by Cassells and Ball concerning the importance of communicating information about difficult airways, particularly in avoiding future risk for patients and legal liability 1, 2. Several publications have previously contained examples of airway alert notifications 3, 4, but non-standardised notification practices are still common 5 and no formalised approach to notification has been published so far. Currently, the definition of a difficult airway event varies widely among different anaesthesia providers. It may include factors such as difficult or impossible mask ventilation, difficulty or inability to see the larynx directly and secure the airway, or even just a non-rational, personal feeling of a potential airway difficulty. Triggers for when to communicate and document a difficult airway event, therefore, depend on both whether any defined criteria are encountered and any subsequent action by the particular anaesthetist involved. When a patient with a difficult airway presents for future surgery, however, airway assessment is the poorer for not having access to contemporaneous reports of previous difficulties. Indiscriminate or ‘blanket’ use of airway alert forms can also be problematic, decreasing the ability of future anaesthetists to detect potential problems with previously difficult airways. To improve the quality of notification at our hospital, we have developed empirical criteria about when to release an airway alert form (Table 1). Alert forms are issued for patients with unexpectedly difficult airways who had undergone a structured, thorough and unremarkable pre-operative airway examination, as we strongly believe that these patients are the ones who benefit most from an alert form. We do not issue alert forms for patients with obvious predictors for airway difficulties, as these should be identified in advance 6 and managed according to existing difficult airway algorithms. Unexpected difficult mask ventilation (despite supportive measures) in combination with unexpected difficult intubation (despite supportive measures) Any airway difficulty requiring awakening the patient and subsequent awake intubation (e.g. awake fiberoptic intubation, awake tracheotomy) Any ‘cannot intubate, cannot oxygenate’ events with or without emergency surgical airway Any permanent space-occupying lesions or barriers with the potential risk of airway obstruction, undetectable by a thoroughly conducted physical examination The airway difficulties encountered The airway management techniques used (both successful and unsuccessful) Prospective outcome studies about alert form criteria and which patients benefit the most from them are currently lacking, and it is not known how many alert forms are needed to prevent one adverse airway event. Further, our criteria are not yet confirmed by scientific evaluation. Until such time as properly conducted research is undertaken, however, we commend our criteria as a pragmatic solution to this problem, and urge national airway working parties to consider publishing consensus statements on the same.