Local anaesthesia for awake fibreoptic nasotracheal intubation

Awake fibreoptic nasotracheal intubation (FNI) is performed in potentially difficult airways under local anaesthesia. This observer-blinded study was designed to evaluate the efficacy of upper airway anaesthesia produced by nebulized lignocaine against combined regional block (CRB) for awake FNI.

Forty-eight ASA 1 adults were randomly allocated to receive 4 ml of 4%-nebulized lignocaine (nebulization group) or translaryngeal block, bilateral superior laryngeal nerve block and three 4% lignocaine-soaked cotton swabs in the nose (CRB group). Facial grimace and patient comfort were assessed by grimace and airway reactivity scores. Patients reported their discomfort on a 4-point score.

All patients underwent successful FNI without significant discomfort; 79% in the nebulization group and 83% of the patients in the CRB group reported the procedure to be comfortable. A higher grimace score was recorded on insertion of the endotracheal tube (ETT) through the nostril in the nebulization group when compared to the CRB group, P<0.005. Similarly, patients in the CRB group were more comfortable during passage of the ETT into the glottis, as compared to the nebulization group. A progressive increase in heart rate was observed in all patients from the beginning of the procedure, but the rise in the nebulization group was greater, (P<0.05) and also lasted longer than in the CRB group (P<0.05). Mean arterial pressure was higher in the nebulization group when compared to the CRB group (P<0.05), with patients belonging to the CRB group demonstrating considerable haemodynamic stability.

Both nebulization and CRB produced satisfactory anaesthesia of the upper airway, but CRB provided better patient comfort and haemodynamic stability.