Does topical anesthesia using aerosolized lidocaine inhibit the superior laryngeal nerve reflex?

OBJECTIVE

This study was designed to evaluate the effectiveness of topical lidocaine in attenuating the laryngeal reflex and blunting hemodynamic response by inhibition of the superior laryngeal nerve in laryngeal microsurgery, which would be helpful in preventing potential complications.

STUDY DESIGN

A prospective, randomized, double-blind study.

SETTING

Tertiary medical center.

SUBJECTS AND METHODS

Fifty-four patients requiring glottic and supraglottic laryngeal microsurgery were randomly assigned to 1 of 2 groups, with equal numbers. Before surgery, 10% lidocaine was topically applied to the laryngeal surface of the epiglottis and vocal folds under direct vision in the study group and saline aerosol was applied in the control group. Heart rates, arterial blood pressure, and SPO2 were recorded at baseline, after induction, immediately before and after intubation, during the surgery, and upon extubation. Laryngospasm, agitation, and coughing were recorded during the recovery period.

RESULTS

Heart rates, arterial pressure, and SPO2 did not differ significantly from baseline to postintubation period among the groups. SPO2 values measured similar in the remaining study. Heart rates and blood pressures were slightly decreased in the study group after lidocaine administration, but only blood pressure at pre- and post-extubation was significantly decreased in the study group (P < .05). Also laryngospasm and coughing were not statistically different between the 2 groups. There was an obvious gap between the 2 groups for agitation. Study group agitation was noted significantly lower (P < .05).

CONCLUSION

These findings indicate that preoperative topical lidocaine application may be helpful in attenuating airway-circulatory reflexes in laryngeal microscopic surgery.