REGIONAL BLOOD-FLOW EFFECTS OF DOPEXAMINE VERSUS ENALAPRILAT DURING PROPOFOL ANESTHESIA IN RABBITS WITH EXPERIMENTAL CHRONIC HEART-FAILURE

Objective: Chronic congestive heart failure (CHF) was induced in rabbits with doxorubicin in order to evaluate: (1) haemodynamic and regional blood flow responses to propofol anaesthesia; (2) modification of these cardiovascular responses with background intravenous infusions of enalaprilat or dopexamine. Methods: Rabbits received either doxorubicin, 2 mg.kg(-1) weekly intravenously for seven weeks (CHF, n = 6), or saline (controls, n = 6). Doppler flow probes were implanted on the ascending aorta, left renal artery, and lower abdominal aorta. In three separate studies propofol was infused for 40 min periods at 0.6 and then 1.2 mg.kg(-1).min(-1) after background infusions of either saline, enalaprilat (0.2 mg.kg(-1) + 0.003 mg.kg(-1).min(-1)), or dopexamine (0.008 mg.kg(-1).min(-1)). Results: In normal rabbits propofol (1.2 mg.kg(-1).min(-1)) reduced mean arterial pressure from awake control by 33(SEM 3)%, cardiac output by 24(4)%, and hindlimb blood flow (HBF) by 10(2)%, but did not change renal blood flow. In rabbits with CHF although resting mean blood pressure was lower, propofol did not alter blood pressure or hindlimb blood flow, but renal blood flow was reduced by 37(6)%. Conclusions: Both enalaprilat and dopexamine increased renal blood flow in the control and CHF groups. Enalaprilat caused marked hypotension during anaesthesia in the CHF group. Dopexamine increased mean arterial pressure, heart rate, and hindlimb blood flow during anaesthesia in controls, but not in CHF.