Metabolic effects of propofol and flunitrazepam given for sedation after aortic surgery

Sixteen patients who had undergone abdominal aortic surgery were allocated randomly to receive either propofol (total dose 3.2 (SEM 0.3) mg kg-1 h-1) or flunitrazepam (total dose 15 (2) micrograms kg-1 h-1) for 16 h after operation. Metabolic effects of sedation were assessed using a Deltatrac metabolic monitor. Initiation of sedation induced a 25% decrease in VO2 in both groups. The decrease was about 40% at 16 h. VO2 increased within 30 min after discontinuation of propofol and stabilized at values considerably less than the immediate postoperative value. A similar but slower increase was noted with flunitrazepam. While the propofol loading dose reduced the Buffington index and should therefore be avoided, no cardiovascular side effects were noted with the maintenance infusion. Weaning from ventilatory support was achieved within 15 (2) min and 264 (108) min after discontinuation of propofol and flunitrazepam, respectively.