[Hemodynamics and changes in compliance of the extra-thoracic capacity system following administration of...

Hemodynamic effects of prostacyclin (PGI2) given as an intravenous infusion at a rate of 8 ng/kg/min were assessed in 50 patients with coronary artery disease at the time of aortocoronary bypass surgery. 1. During steady-state neuroleptic anesthesia, after sternotomy and pericardiotomy, before cannulation of the aorta and vena cava PGI2 led to the following changes: decreases in mean arterial pressure (-24%), total peripheral resistance (-46%), left ventricular pressure (-12%) and left ventricular end-diastolic pressure (-48%), increases in heart rate (+9%), cardiac output (+41%), stroke volume (+30%) and dp/dtmax (+26%) as well as nonsignificant decreases in right ventricular filling pressure (-13%) and mean pulmonary arterial pressure (-9%) together with an unaltered rate-pressure product. 2. In a randomized double-blind study PGI2 was infused throughout the period from two minutes prior to, until termination of extracorporeal circulation. The effects on compliance of the extrathoracic venous system were analyzed on the basis of changes in venous pressure and oxygenator volume. As compared with controls, patients receiving PGI2 were found to have a significant increase in compliance (.157 ml/mm Hg X kg). Thus, in this setting, PGI2 can affect marked vasodilatation with reductions in peripheral resistance and mean arterial pressure together with increases in cardiac output and heart rate.