Constant intravenous infusion of chlorpromazine for both sedation and after-load reduction in postcardiotomy patients under intraaortic balloon pumping.

Continuous intravenous infusion of chlorpromazine (CPZ) was used for both sedation and after-load reduction in 13 Japanese patients (Group 1) supported by an intraaortic balloon pump (IABP) after open-heart surgery. CPZ was initiated at a dose of 0.05 mg/kg/hr and was maintained in an approximate dose range of 0.1-0.3 mg/kg/hr depending on individual patient needs. The drug was administered until the IABP was removed and the blood gases were normalized. During this period, the patients slept well and the trigger lines for the IABP were sufficiently secured. In order to evaluate the hemodynamic changes in these patients, the 10 patients who were supported by the IABP and given continuous intravenous sodium thiamylal (ST) for sedation in an approximate dose range of 1-2 mg/kg/hr (Group 2) were employed as controls. After administration of CPZ, the systemic vascular resistance, central venous pressure, and left atrial pressure decreased, while the cardiac output increased. The predicted untoward effects of CPZ, such as tachycardia and hypotension, were minimal. In the ST group, by contrast, the cardiac output decreased somewhat in association with the increase in systemic vascular resistance. From these results, we conclude that constant intravenous CPZ is beneficial for postcardiotomy patients who have severe low cardiac output syndrome and are supported with IABP, by both successfully sedating the patients and reducing ventricular afterload.