BACKGROUND: Laryngeal microscopic surgery is stressful as a result of the intubation and suspension laryngoscopy during the short operation time. Therefore, the objectives of the anesthesiologist are to maintain sufficient anesthetic depth, promote rapid awakening, and return the protective airway reflexes. This study compared the hemodynamic responses and recovery patterns between propofol-N₂O and sevoflurane-N₂O anesthesia.

METHODS: Sixty outpatients undergoing laryngeal microscopic surgery were randomly divided into three groups: Endotracheal intubation with the effect-site concentration of propofol fixed at 3 ug/ml (Group P3), 4 ug/ml (Group P4) or endotracheal intubation with sevoflurane anesthesia (Group S). In all groups, the anesthesia was supplemented with up to 50% of N₂O. The hemodynamic responses during intubation and suspension laryngoscopy were compared. In addition, extubation time, emergence time and the state of recovery (Steward score) were compared.

RESULTS: After intubation and suspension laryngoscopy, the mean arterial pressure was significantly higher in Group S than in Groups P3 and P4 (P < 0.05). The heart rate was significantly higher in Group S than in the Group P4 (P < 0.05). The extubation times were not significantly different. However, the time for responding to a verbal command was significantly faster in Groups P3 (7.8 ± 2.3 min) and P4 (8.8 ± 1.9 min) than in Group S (10.6 ± 1.8 min). The Steward score 1 min after extubation was significantly higher in Group S (P < 0.05).

CONCLUSIONS: Propofol-N₂O anesthesia can be useful in laryngeal microscopic surgery.