| Abstract: | The vasodilatory properties of prostacyclin were studied in 12 intubated patients who underwent coronary artery bypass surgery. When infused in doses of 2.5, 5, 10, and 20 ng/kg/min, prostacyclin produced a dose-dependent decrease in systemic vascular resistance from 2,702 +/- 143 to 1,654 +/- 106 dynes/cm5/m2 (p less than 0.05). Heart rate, right atrial pressure, and pulmonary arterial and capillary wedge pressures did not change. Cardiac function was improved, since stroke volume index increased from 29.5 +/- 1.4 to 35.5 +/- 2.0 ml/min/m2 (p less than 0.05) and the rate pressure product decreased from 13.3 +/- 1.3 to 10.9 +/- 0.9 X 10(3) mm Hg/beats/min (p less than 0.05), while stroke work index remained unchanged. These hemodynamic changes were associated with a dose-dependent decrease in arterial oxygen tension which occurred from 278 +/- 25 to 133 +/- 22 mm Hg; however, oxygen transport increased as a result of the prostacyclin-induced increase in cardiac index. This study demonstrates that prostacyclin is a potent arterial vasodilator that may be of interest in the treatment of postoperative vasoconstriction occurring after coronary artery bypass surgery. |
