Comparison of two techniques of airway anaesthesia for awake fibreoptic nasotracheal intubation in patients with anticipated difficult airway

Abstract

Introduction: The success of awake fibreoptic assisted intubation often depends on the adequacy of anaesthesia of the airway and patient comfort for the procedure. Aim: To compare the standard technique (nerve block) of airway anaesthesia with simple aspiration of lignocaine. Methods: Thirty patients in whom difficult airway was anticipated were randomly allocated into either Group A (Aspiration) and Group B (Nerve block). In Group A, 0.2 mL/kg of 1.5% lignocaine was trickled on to the dorsum of the tongue while the patient was encouraged to breathe through the mouth. In Group B, superior laryngeal nerve block and intratracheal injection of lignocaine was used. Fibreoptic bronchoscopy was then carried out by a consultant anaesthesiologist, who was blinded to the local anaesthetic technique used. The patient responses to instrumentation of pharynx, glottis and trachea, and tolerance of the endotracheal tube were noted. Results: Two cases were excluded from the study because of bleeding resulting in subsequent loss of visualisation of glottis through bronchoscope. There was no statistical or clinical difference in the patient responses between the two groups (P > 0.05) due to fibreoptic bronchoscope in the pharynx, larynx and endotracheal tube in the trachea or with regard to the use of rescue medications. Conclusions: Aspiration of 1.5% lignocaine (0.2 mL/kg) provides clinically comparable conditions for intubation as the nerve block technique for awake fibreoptic nasotracheal intubation in patients with anticipated difficult airway.