Letters to the Editor: Letter to the Editor
Incomplete Airway Assessment
We thank Dr. Nørskov et al1 for their thoughtful comments concerning our editorial.2 We also are grateful for their clarification of methods used for airway assessment in their Danish Anaesthesia Database study.1
Although it is clear that airway evaluation before intervention is a critical step to minimize adverse outcomes, we agree with Nørskov et al1 that there is ample room for improvement in the evaluation tools we have to date. In other words, because unanticipated difficulties in managing the airway will likely continue to occur in our clinical practice, airway practitioners must be equipped with a strategy to manage an unanticipated difficult or failed airway (ie, plan B, plan C).3–5
Recognizing that the survey mentioned in our editorial2 was an informal solicitation of information regarding the airway evaluation section of preanesthetic assessment forms (an image taken from a smartphone), there is potential for bias in our data collection. The countries involved in our survey included Australia, Canada, England, Germany, Italy, the Netherlands, New Zealand, Singapore, Rwanda, and the United States. As summarized in our editorial, the airway assessment section on these forms varied substantially, ranging from descriptive text only to a list of predictors of difficult direct laryngoscopy with Mallampati score, this latter, the most common predictor present on these preanesthetic assessment forms. On the basis of the information collected, we concluded that assessment for difficult direct laryngoscopy remains the main focus of airway assessment at many centers around the globe. The form from our center at Dalhousie University was the only one asking for predicted difficulty in bag-mask ventilation and surgical airway (cricothyrotomy). None of the forms surveyed queried assessment of predicted difficulty in using an extraglottic device, such as a laryngeal mask airway.
We agree with Nørskov et al1 that we must find solutions to improve and correct problems related to incomplete airway assessment. In addition to assessing the patient for predicted difficulty with direct or video laryngoscopy, we must stress the importance of assessing difficulties in other methods in oxygenation and ventilation. These include difficulties in bag-mask ventilation, the use of an extraglottic device (eg, a laryngeal mask airway), and front-of-neck access (cricothyrotomy) so that appropriate airway management strategies can be planned before intervention. Adverse patient physiology (eg, full stomach, anticipated intolerance of apnea) with the potential to impact the choice of approach to the airway also must be considered.
Orlando Hung, MD, FRCPCJ. Adam Law, MD, FRCPCIan Morris, MD, FRCPCDepartment of Anesthesia, Pain Management andPerioperativeMedicineDalhousie UniversityHalifax, Nova Scotia, Canadahung192@gmail.com
Michael Murphy, MD, FRCPCDepartment of Anesthesiology and Pain MedicineUniversity of AlbertaEdmonton, Alberta, Canada
1. Nørskov AK, Rosenstock CV, Wetterslev J, Astrup G, Afshari A, Lundstrøm LH. Diagnostic accuracy of anaesthesiologists’ prediction of difficult airway management in daily clinical practice: a cohort study of 188 064 patients registered in the Danish Anaesthesia Database. Anaesthesia. 2015;70:272281.
2. Hung O, Law JA, Morris I, Murphy M. Airway assessment before intervention: what we know and what we do. Anesth Analg. 2016;122:17521754.
3. Apfelbaum JL, Silverstein JH, Chung FF, et al. Practice guidelines for postanesthetic care: an updated report by the American Society of Anesthesiologists Task Force on Postanesthetic Care. Anesthesiology. 2013;118:291307.
4. Frerk C, Mitchell VS, McNarry AF, et al.; Difficult Airway Society intubation guidelines working group. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth. 2015;115:827848.
5. Law JA, Broemling N, Cooper RM, et al.; Canadian Airway Focus Group. The difficult airway with recommendations for management–part 1–difficult tracheal intubation encountered in an unconscious/induced patient. Can J Anaesth. 2013;60:10891118.