Haemodynamic effects of propofol infusion for sedation after coronary artery surgery

We have compared the haemodynamic effects of a sedative dose of propofol with placebo (vehicle of propofol) in a randomized, double-blind study in 20 patients immediately after coronary artery bypass grafting (CABG). During a continuous infusion of a mixture of fentanyl and pancuronium, each patient was given in a crossover design, a loading dose of propofol 0.5 mg kg-1 and vehicle over 5 min followed by a continuous infusion of propofol 20 micrograms kg-1 min-1 and vehicle, respectively, for 55 min. Administration of propofol caused a significant decrease in mean arterial pressure (mean change from pre-drug values to those during drug infusion: -15.4% vs +1.3% with placebo; P < 0.001), mean pulmonary artery pressure (-6.5% vs +5.8%; P < 0.001), systemic vascular resistance (-13.8% vs -0.6%; P < 0.05), pulmonary vascular resistance (-2.0% vs +9.0%; P < 0.05), cardiac output (-2.4% vs +2.6%; P < 0.05) and pulmonary artery occlusion pressure (-8.0% vs +1.4%; P < 0.05). Propofol did not affect heart rate, but it tended to decrease stroke volume (P = 0.102). These data suggest that, during the recovery phase from CABG surgery, a short-term infusion of a sedative dose of propofol decreases systemic and pulmonary arterial pressure by decreasing systemic and pulmonary vascular resistance, respectively, and cardiac output. The decrease in cardiac output appeared to be caused mainly by a decrease in stroke volume.