[Studies of midazolam, diazepam and thiopentone on respiratory and cardiovascular function during induction anesthesia].

In this study, the effects of midazolam (M), diazepam (D) and thiopentone (T) on respiratory and cardiovascular systems were compared. The patients were randomly divided into 6 groups, besides minute ventilatory volume (MV), onset of induction and cardiovascular changes were also observed. Induction was performed by a bolus injection of one of the following: midazolam (0.3 mg/kg), diazepam (0.3 mg/kg) or thiopentone (5 mg/kg). Five minutes later, 5 micrograms/kg fentanyl and 1.5-2.0 mg/kg succinylcholine were administered. The results showed that: (1) Inhibitory effect on MV was not prominent and similar after use of midazolam and diazepam but was remarkable after thiopental; (2) As for the onset, midazolam was faster than diazepam but slower than thiopentone; (3) Hemodynamic changes of midazolam, diazepam and thiopentone were similar, however during intubation, cardiovascular response was the least in midazolam, diazepam the intermediate and thiopentone the most significant. We conclude that midazolam is a water-soluble, safe and effective inductive anesthetic with its short eliminated half-life period, and much lesser venous irritation, and it is certainly superior to both diazepam and thiopentone.