The effect of preemptive morphine hcl on the consumption of desflurane and anesthesia recovery

Purpose: In this study, the effect of two different doses of morphine used at anaesthesia induction on desflurane consumption, extubation and recovery times, postoperative pain and analgesic consumption were investigated. Material and Method: In this placebo controlled, double blinded, randomized study, 90 patients undergoing total abdominal hysterectomy were recruited after approval of faculty ethical committee and patient consent. After anaesthesia induction (thiopental sodium, 5 mg/kg, iv), first group received 10 ml of salin 0,9%, second group received 0.1 mg/kg of morphine sulphate and third group received 0,2 mg/kg of morphine sulphate intravenously. Anaesthesia was maintained with desflurane (6%) in a mixture of oxygen (33%) and nitrous oxide (66%). The depth of anaesthesia was monitorized with bispectral index (BIS) technique. BIS levels were kept within 40-60 by changing the concentration of desflurane (1%). Desflurane concentrations and consumption, time to extubation, time to recovery, postoperative pain and supplement analgesic consumption were recorded during the operation and early postoperative period. Results: Compared with control group, at all study periods, BIS values were significantly lower in the both morphine groups. Desflurane consumption was significantly lower in patients receiving both two different doses of morphine at anaesthesia induction (consequently 72,75 ml, 48,22 ml and 15,53 ml), (p<0.001). In the morphine groups the extubation and recovery times were longer than control group. Postoperative analgesic requirements were higher in the control group than morphine groups, while more supplemental analgesic were required in the low dose morphine group than high dose morphine group. Conclusion: In this study, it was concluded that two different doses of intravenous morphine used at anaesthesia induction increased the time to recovery without changing time to extubation, but decreased the consumption of desflurane and postoperative analgesic consumption in the patients undergoing total abdominal hysterectomy.