Hemodynamic effects of mivacurium chloride administered to patients during oxygen-sufentanil anesthesia for coronary artery bypass grafting or valve replacement.

The hemodynamic effects of mivacurium chloride were studied in 54 adult cardiac patients anesthetized with midazolam and sufentanil. After baseline data were collected, a placebo (N = 9) or mivacurium was administered over 60 seconds, the latter in doses of 0.15 (N = 18), 0.20 (N = 18), or 0.25 (N = 9) mg/kg. Measurements were repeated 2, 5, and 10 minutes later. Baseline measurements were similar. A slight decrease in heart rate over time reached statistical significance in several groups including the control group. Mean arterial, mean pulmonary arterial, pulmonary arterial occlusion, and right atrial pressures and cardiac output did not change, nor did systemic and pulmonary vascular resistances and cardiac index. Besides the decrease in heart rate, the only hemodynamic change to reach statistical significance was an increase in stroke volume in patients given mivacurium 0.25 mg/kg. Significant hypotension occurred in two patients; in one, a sudden decrease in mean arterial pressure of 24% occurred 1 minute after mivacurium 0.20 mg/kg. Blood pressure was restored by ephedrine 10 mg. In the other patient, given mivacurium 0.25 mg/kg, mean arterial pressure decreased 50% from 73 to 37 mm Hg. Recovery was rapid without treatment. It is concluded that mivacurium administered in doses of 0.15 to 0.25 mg/kg over 60 seconds to cardiac patients is associated with few significant hemodynamic effects. However, a small number of patients may experience significant transient hypotension when given doses greater than of 0.15 mg/kg, two times the ED95.