[Comparison of the hemodynamic effects of midazolam-fentanyl and thiopental-fentanyl combinations in the induction of general anesthesia].

The hemodynamic changes during anesthetic induction for elective abdominal aortic surgery were studied in two groups of patients. Group M (9 patients) received midazolam 0.3 mg . kg-1 and fentanyl 6 micrograms . kg-1. Group T (10 patients) received thiopentone 6 mg . kg-1 and fentanyl 5 micrograms . kg-1. The radial and pulmonary arteries were catheterized under local anesthesia. An intravenous infusion was administered in order to normalize pulmonary wedge pressure. Systemic and pulmonary arterial pressures, pulmonary wedge pressure, cardiac output and heart rate were measured after the infusion and 5 min after intubation. Mean arterial pressure showed a statistically significant reduction in both groups. Cardiac index remained unchanged in group M, but was significantly diminished in group T. There was no significant reduction in the systemic vascular resistance index for group M, but group T showed a statistically significant increase. This study confirmed the good hemodynamic tolerance of the midazolam induction technique, even with a high dose of 0.3 mg . kg-1.