The role of pre-induction ketamine in the management of postoperative pain in patients undergoing elective gynaecological surgery at the University Hospital of the West Indies

Abstract

Objectives: To determine if a single preoperative dose of ketamine hydrochloride reduces the narcotic analgesic requirements and/or pain scores reported by patients in the first 24 hours postoperatively.

Methods: A single-centred, prospective, case-control study was conducted on 84 patients aged 18-65 years, American Society of Anaesthesiologists (ASA) I and II, undergoing elective gynaecological procedures at the University Hospital of the West Indies (UHWI). Patients were randomly assigned to one of two treatment groups: (a) ketamine group, where patients received intravenous ketamine 0.15 mg/kg pre-induction of anaesthesia; and (b) placebo group, patients received normal saline. The anaesthetic technique was standardized. Postoperatively, patients were interviewed at 15-minute intervals for the first hour then at 2, 4, 6, and 24 hours to determine their pain scores and any side effects. Timing and dose of opioid analgesics were also recorded.

Results: The mean cumulative morphine dose over the first 24 hours postoperatively was 29.6 +/- 10.8 mg for the ketamine group and 31.9 +/- 11.2 mg for the placebo group (p = 0.324). There was also no significant difference in pain intensity measured by the visual analogue scale (VAS) between the groups. Patient age and the type of surgery performed were not found to influence pain intensity. The most common adverse effects were nausea and vomiting (32.5%), dizziness (42.2%), drowsiness and sedation (45.8%) with no significant difference between groups. Both groups had an average in-hospital stay of three days postoperatively, however, the patients in the ketamine group reported higher satisfaction scores than those in the placebo group (p = 0.039).

Conclusion: Despite no significant reduction in postoperative narcotic requirements or pain intensity, more patients who received ketamine reported higher levels of satisfaction with their pain management.