THE SITE OF AIRWAY IRRITATION DURING INDUCTION OF ANESTHESIA

The aim of this investigation was to study the role of the nasal airwa y in mediating upper airway reflexes during induction of anaesthesia w hen the commonly used irritant inhalational anaesthetic agent enfluran e is used. In a prospective randomised study 40 ASA 1 & 2 day-case pat ients undergoing body surface surgery were recruited. Following intrav enous induction using propofol, 20 patients received enflurane adminis tered via a laryngeal mask airway (LMA), the anaesthetic vapour theref ore bypassing the nasal airway. In the other group, 20 patients receiv ed enflurane anaesthesia administered using a face mask, the nasal air way therefore being exposed to inhalation anaesthetic. We were unable to demonstrate any significant (p < 0.05) differences between the two groups in relation to upper airway complications (cough, breath holdin g, laryngeal spasm, bronchospasm and excitement). Previous work has id entified the nose as a possible important reflexogenic site for upper airway reflexes in humans during anaesthesia. We have been unable to d emonstrate any difference in upper airway complications when the nasal airway was included or excluded from exposure to irritant anaesthetic vapours, when administered in a clinical setting.