[Induction of anesthesia with midazolam and thiamylal]

Midazolam has a slow onset of action, while thiamylal causes pain on injection and circulatory changes. To compensate for these drawbacks, the usefulness of a combination of midazolam and thiamylal in anesthesia induction was studied. The combination method was compared to the induction with single use of thiamylal in 40 patients (20 patients in each group). The combination of 0.2 mg.kg-1 of midazolam and 1.9 mg.kg-1 of thiamylal showed a shorter onset of action than the 4-5 mg.kg-1 of thiamylal. Pain on injection was observed in 5 cases of thiamylal group but in no cases of combination group. The changes in blood pressure, heart rate and rate pressure product were obviously smaller in combination group than in thiamylal group. Although the recovery time from anesthesia of combination group (13.2 minutes) was longer than that of thiamylal group (10.5 minutes), this was not clinically important. It is concluded that anesthesia induction with the combination of midazolam 0.2 mg.kg-1 and thiamylal 1.9 mg.kg-1 is more useful than that of thiamylal alone.