Many studies have shown that tracheal intubation can be facilitated by propofol-remifentanil without muscle relaxant. But low dose of rocuronium can improve intubating condition and reduce the requirement of remifentanil. This study evaluated the optimal dose of rocuronium for tracheal intubation according to different doses of rocuronium during propofol-remifentanil target controlled infusion (TCI).

Sixty, ASA I-II patients were randomly divided into three groups (n = 20). Anesthesia was induced with remifentanil 3.0 ng/ml and propofol 3.5 µg/ml target controlled infusion. After patients lost consciousness, rocuronium was administrated 0.6 mg/kg (R0.6), 0.45 mg/kg (R0.45), 0.3 mg/kg (R0.3) for each group. Three minutes later, a laryngoscope and tracheal intubation were tried, intubating condition were measured. Also blood pressure and heart rate were measured before induction, preintubation, postintubation.

Clinically acceptable intubation condition (excellent or good) were observed 100%, 100%, 85% of patients in the R0.6, R0.45, and R0.3 groups. Eighty five percents of patients in groups R0.6, R0.45 had excellent intubation condition. But only 35% in group R0.3 showed excellent intubating condition (P < 0.05) and 15% in group R0.3 showed poor intubating condition. There were no significant elevation mean blood pressure (MBP), heart rate (HR) after tracheal intubation in all groups. And there were no significant differences among groups.

The optimal dose of rocuronium for clinical acceptable intubating condition could be reduced to 1.5 × ED₉₅ under total intravenous anesthesia with remifentanil 3.0 ng/ml and propofol 3.5 µg/ml target controlled infusion.