Effects of graded infusion rates of propofol on cardiovascular haemodynamics, coronary circulation and myocardial metabolism in dogs.

We have studied the effects of a 30-min infusion of propofol 6, 9, 12, 15, 18 and 21 mg kg-1 h-1 on cardiovascular haemodynamics, coronary circulation and myocardial metabolism in 12 mongrel dogs. Mean plasma concentrations of propofol after infusion of 6 and 21 mg kg-1 h-1 increased from 2.9 (SEM 0.3) to 11.5 (0.1) micrograms ml-1. Propofol produced a progressive decrease in arterial pressure. Heart rate tended to decrease at 15, 18 and 21 mg kg-1 h-1 and cardiac index decreased significantly at infusion rates > or = 9 mg kg-1 h-1. Systemic vascular resistance tended to increase except at 21 mg kg-1 h-1 and left ventricular systolic and diastolic function were depressed. Both coronary sinus blood flow and myocardial oxygen consumption decreased in parallel with a decrease in left ventricular minute work index without producing lactate. Propofol produced progressive decreases in coronary blood flow and myocardial oxygen consumption but did not exert adverse effects on the coronary circulation.