Subcutaneous ketamine for postoperative pain relief in Rwanda: a randomized clinical trial

Purpose Postoperative pain control is often inadequate in low-income countries such as Rwanda, prompting the search for an inexpensive improvement. A randomized controlled trial was conducted to study the use of subcutaneous ketamine for the management of postoperative pain in patients undergoing major surgery in Kigali, Rwanda. Methods Fifty-nine patients undergoing major abdominal, head and neck, plastic, or gynecological surgeries were studied. In addition to standard care, patients received five subcutaneous injections of ketamine 1 mg.kg(-1) (ketamine group, n = 30) or normal saline (placebo group, n = 29) during the postoperative period. The first injection was administered in the postanesthesia care unit and then every 12 hr thereafter starting at 20:00 on the day of surgery. Pain was assessed three times per day using an 11-point verbal response scale. Patients were also assessed for side effects, including nausea and vomiting, hallucinations, nightmares, sedation, hypertension, and seizures. Results The mean (SD) overall postoperative pain scale score was higher in the control group than in the ketamine group [4.8 (1.7) vs 3.7 (1.5), respectively; difference of means, 1.1; 95% confidence interval [CI], 0.3 to 1.9; P = 0.009]. Brief hallucinations (ketamine group, 11 patients; placebo group, 0 patients; risk difference, 0.37; 95% CI, 0.18 to 0.54; P < 0.001) were associated with ketamine administration. Conclusions Results of this study in Kigali, Rwanda showed that subcutaneous administration of ketamine 1 mg.kg(-1) twice daily, in addition to standard postoperative care, produced a small improvement in postoperative pain but resulted in more minor side effects