In ambulatory surgery, which is of short duration, anesthesiologists often do not use a muscle relaxant, or any other induction technique which could facilitate muscle relaxation for endotracheal intubation. Incomplete muscle relaxation, however, results in vocal cord movement and the possibility of damage to the vocal cords and adjacent structure. The aim of this study was to evaluate the macroscopic sequelae of intubation on vocal cord and laryngeal structure and assess postoperative sore throat or hoarseness.

100 patients with class I or II ASA physical status were enrolled in this study. It was divided into two groups, Group C (conventional intubation dose of rocuronium; 0.6 mg/kg) and group L (low intubation dose 0.45 mg/kg). Anesthesia was induced with 10 µg/kg of alfentanil and 2.0 mg/kg of propofol i.v. Intubation was performed 90 second after rocuronium injection and the intubation condition was checked. Macroscopic sequelae ofthe laryngeal structure were evaluated using a flexible fiberoptic bronchoscope. After completion of surgery, the patient was asked to report sore throat or hoarseness.

Macroscopic sequelae, such as erythema or hemorrhage, were statistically different between the two groups. There were no cases of minimal hemorrhage of either vocal cords or of the arryepiglottic folds in group C whereas there were two cases in group L. There was no statistical difference in incidence and severityof sore throat or hoarseness between the two groups.

Although there were more macroscopic effects in the vocal cords and aryepiglottic folds, a low intubation dose of rocuronium can be used during surgery of short duration without fear of any significant sore throat or hoarseness after surgery.