[Haemodynamic effects of vasodilators in dogs--a comparison of prostaglandin E1, nicardipine and nitroglycerin].

Effects of vasodilation by prostaglandin E1 (PGE1), nicardipine (NIC) and nitroglycerin (TNG) were investigated separately in adult mongrel dogs. Mean arterial pressure was lowered and maintained at 90% and 70% of the control value. Cardiac output (CO), pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP) were measured by a thermodilution pulmonary artery catheter and blood flow of hepatic artery (HABF), portal vein (PVBF) and mesenteric artery was measured by electromagnetic flowmetry. 1) PGE1: Heart rate (HR) and CO were unchanged and left ventricular stroke work (LVSW) decreased. HABF was unchanged, but PVBF increased significantly. 2) NIC: HR increased and systemic vascular resistance decreased significantly. Therefore, CO increased remarkably, compared with the other two drugs. Though LVSW was unchanged, right ventricular stroke work (RVSW) increased with elevation of PAP. In the hepatic circulation, HABF and PVBF decreased slightly. 3) TNG: LVSW and RVSW decreased significantly. HABF increased slightly and PVBF increased significantly.