The efficacy of nicardipine and nitroprusside in preventing poststernotomy hypertension

The efficacy of nicardipine and nitroprusside in preventing poststernotomy hypertension was compared in two groups of 45 patients undergoing coronary artery surgery. Patients were anesthetized with fentanyl, 100 micrograms/kg, and oxygen. Group N received nicardipine at an initial rate of 3 micrograms/kg/min. Group S received sodium nitroprusside at an initial rate of 1 microgram/kg/min. The vasodilators were started before surgery, and infusion rates were adjusted to maintain systolic blood pressure between 80% and 120% of postintubation (baseline) values. Additional measurements were obtained before incision and after sternotomy. In both groups, arterial blood pressure could be controlled effectively in all patients. In group S, pulmonary artery pressure (PAP) decreased before incision. At this time, systemic vascular resistance (SVR) decreased in both groups. After sternotomy, PAP returned to baseline values in group S. In both groups, heart rate, rate-pressure product, and cardiac index increased, while SVR remained decreased. In the period from induction of anesthesia to the start of cardiopulmonary bypass, the incidence of myocardial ischemia was greater (P less than 0.01) in group S (24%) than in group N (9%). Between the groups, the concentration of creatine phosphokinase MB was not significantly different in the first 24 hours postoperatively. In conclusion, it was shown that nicardipine may be a suitable alternative to nitroprusside for the prevention of poststernotomy hypertension and myocardial ischemia in patients undergoing coronary artery surgery.