[Ketamine racemate and fast track anaesthesia. Influence on recovery times and postoperative opioid needs]

Abstract

Introduction: In this study the impact of 25 mg of ketamine racemate given just before surgery on recovery times and postoperative analgesic needs in patients undergoing vaginal hysterectomy and receiving propofol-remifentanil anaesthesia was investigated.

Methods: With ethics committee approval 70 female patients aged 25-65 years were enrolled. All patients received a total intravenous anaesthesia with remifentanil and propofol with the propofol infusion being controlled to a Narcotrend index of 40. Patients in the ketamine group (n=35) received additionally a bolus dose of 25 mg ketamine racemate intravenously 3 min before skin incision. In addition to monitoring haemodynamics and circulation parameters, recovery times, postoperative pain and opioid needs were also recorded. Patients were also questioned on their satisfaction with the pain therapy.

Results: All 70 patients completed the study and the groups were similar with respect to demographic data. The haemodynamics of the patients were stable in both groups and the postoperative pain measured over a 24-h period as well as the opioid needs were also comparable. However, recovery times were significantly prolonged in the ketamine group, e.g. the times to extubation were 8.3+/-4.0 min with ketamine compared to 6.1+/-2.1 min in the control group (p<0.01). Undesired side effects were overall rare but occurred to the same extent in both groups.

Conclusions: This study demonstrated that 25 mg ketamine racemate given just before surgery significantly prolongs recovery times without reducing post-operative analgesic needs when applied to patients undergoing vaginal hysterectomy and receiving propofol-remifentanil anaesthesia. A bolus dose of 25 mg ketamine racemate cannot therefore be recommended for preemptive analgesia under these conditions.