Effect of low-dose propofol infusion on total-body oxygen consumption after coronary artery surgery

Objective: To investigate the effect of low-dose propofol infusion on total -body oxygen consumption ((V)over dotO(2)) after coronary artery bypass gra fting (CABG) surgery. Design: A prospective, randomized, placebo-controlled, double-blind study. Setting: Cardiovascular intensive care unit in a university hospital. Participants: Thirty patients after elective, uncomplicated CABG surgery. Intervention: Patients were administered a continuous infusion of propofol with a fixed rate of 1 mg/kg/h (n = 15) or placebo (n = 15) during the spon taneous rewarming period of approximately 5 hours after surgery. A light le vel of sedation (Ramsay sedation score greater than or equal to 2) was main tained by administering small doses of diazepam, 0.1 mg/kg, as required. Mo rphine, 0.05 mg/kg, was administered for analgesia as required. Measurements and Main Results: Total-body (V)over dotO(2) was measured by i ndirect calorimetry. In addition, shivering (on a five-grade scale), hemody namics, and plasma catecholamine and serum cortisol concentrations were mea sured. Diazepam, 5.6 +/- 7.4 mg (mean +/- standard deviation), was administ ered to the patients receiving propofol, and 16.1 +/- 12.2 mg was administe red to the patients receiving placebo (p < 0.05). There was no difference i n the dose of morphine between the groups (3.2 +/- 3.9 v 4.2 +/- 5.5 mg in the propofol and placebo groups, respectively). At any time during the stud y, (V)over dotO(2) was not different between the groups. (V)over dotO(2) in creased from 130 +/- 29 to 172 +/- 29 mL/min/m(2) in the propofol group and from 118 +/- 24 to 167 +/- 27 mL/min/m(2) in the placebo group. Mean arter ial pressure and heart rate were lower in the propofol group (p < 0.05). St ress hormone levels did not differ between the groups. Conclusion: Low-dose propofol infusion and additional diazepam as required does not decrease total-body (V)over dotO(2) compared with a pure diazepam bolus-dose technique when administered for light sedation during the immedi ate recovery period after CABG surgery. Copyright (C) 1999 by W.B. Saunders Company.