Midazolam causes no adverse hemodynamic effects in cardiac patients

The effects of midazolam on hemodynamic measures were evaluated in 30 patients scheduled for cardiac surgery. The patients were spontaneously breathing 40% oxygen in air and no postural changes or surgical manipulations were allowed before or during the study. Before and 10 minutes after completion of the intravenous infusion of 0.2 mg/kg of midazolam, the following hemodynamic variables were determined: direct radial artery pressure, pulmonary artery pressure, central venous pressure, cardiac output by thermodilution in triplicate via a Swan-Ganz pulmonary artery catheter, and electrocardiograms. Significant (P less than 0.05) reductions in systolic systemic blood pressure, systemic vascular resistance, systemic diastolic blood pressure, and left ventricular stroke work index were observed after midazolam administration. No other hemodynamic changes were statistically significant. Thus midazolam per se caused no adverse, but rather favorable, cardiocirculatory effects since it reduced cardiac work without altering cardiac contractility.