Head and neck surgery in a tertiary centre: Predictors of difficult airway and anaesthetic management

Abstract

Introduction: The management of head and neck surgical patients is associated with increased morbidity and mortality, and so anticipating the difficult airway is important. Methods: We undertook a prospective survey on consecutive adult patients scheduled on the elective operating lists of four head and neck consultant surgeons. Data were collected over a 36 month period. Data included: patient characteristics; routine predictors of difficulty in airway management (bedside tests of the airway, a history of previous surgery or radiotherapy and the presence of airway symptoms); laryngoscopy grade; method of anaesthesia and airway management; and any airway complications arising during induction of anaesthesia and extubation. Results: The ‘study’ group consisted of 818 patients. The ‘direct laryngoscopy’ group contained 674 patients, that is, patients who had direct laryngoscopy and could therefore be classified as easy or difficult intubation. The prevalence of difficult intubation was 12.6%. Factors or tests that were statistically significantly associated with difficult intubation were: history of difficult airway; previous head or neck radiotherapy treatment; presence of airway symptoms; presence of moderate or severe limited neck movement; and short interdental distance. The sensitivity, specificity and positive predictive values were: history of difficult airway 16.5%, 98.6% and 63.6%; previous radiotherapy 12.9%, 96.6% and 35.5%; airway symptoms 42.9%, 69.6% and 15.9%; moderate/severe neck limitation 16.7%, 97.2% and 46.7%; Mallampati score 3 or 4, 38.8%, 83.8% and 25.8%; and interdental distance 9.4%, 98.8% and 53.3%, respectively. The Bonfils intubation fibrescope was the most commonly used indirect laryngoscopy device (63.9% of all such cases). Twenty-six patients (3.2%) had complications during their initial airway management after induction of anaesthesia. There was one case of ‘cannot intubate, cannot oxygenate’, which required an emergency tracheostomy. Conclusion: The prevalence of difficult intubation in head and neck surgical patients was higher than in the general population, but predictive tests for difficult intubation have poor to moderate value. In our study, rates of difficult face mask ventilation, failed intubation and complications during induction and extubation were low. However, serious morbidity, although rare, can still be encountered. Head and neck surgical patients can be managed safely in a tertiary centre where there is appropriate surgical and anaesthetic expertise in managing difficult airways.