Comparison of nitroglycerine, verapamil and nifedipine in the management of arterial pressure during coronary artery surgery.

The efficacy of nitroglycerine, verapamil and nifedipine in controlling post-sternotomy hypertension was compared in four groups of 20 patients anaesthetized with fentanyl 100 micrograms kg-1 undergoing elective coronary artery surgery. Vasodilators were started before surgery and adjusted to maintain systolic arterial pressure less than 120% of pre-infusion values, the mean (+/- SEM) requirements being: nitroglycerine (group II) 3.6 +/- 0.6 micrograms kg-1 min-1; verapamil (group III) 31.1 +/- 2.6 micrograms kg-1 min-1; nifedipine (group IV) 1.7 +/- 0.2 microgram kg-1 min-1. Systolic pressure decreased significantly by 5 min after starting infusions in groups II and III. In the control group (I: no vasodilator) arterial pressure increased significantly following skin incision and sternotomy. Pulmonary arterial and capillary wedge pressures increased significantly following sternotomy in groups I and III. Heart rate increased after sternotomy in all groups, but only reached significance in groups III and IV. There were no significant changes in cardiac index or vascular resistance, although the latter remained lower than pre-infusion values at all times in groups III and IV. The P-Q interval increased significantly in group III. It is concluded that nifedipine is a suitable alternative to nitroglycerine for the control of arterial pressure during coronary artery surgery, but verapamil is not recommended because of its negative inotropic effect and its depressant effect on A-V conduction.