Morphine and Ketamine Is Superior to Morphine Alone for Out-of-Hospital Trauma Analgesia: A Randomized Controlled Trial

Study objective We assess the efficacy of intravenous ketamine compared with intravenous morphine in reducing pain in adults with significant out-of-hospital traumatic pain. Methods This study was an out-of-hospital, prospective, randomized, controlled, open-label study. Patients with trauma and a verbal pain score of greater than 5 after 5 mg intravenous morphine were eligible for enrollment. Patients allocated to the ketamine group received a bolus of 10 or 20 mg, followed by 10 mg every 3 minutes thereafter. Patients allocated to the morphine alone group received 5 mg intravenously every 5 minutes until pain free. Pain scores were measured at baseline and at hospital arrival. Results A total of 135 patients were enrolled between December 2007 and July 2010. There were no differences between the groups at baseline. After the initial 5-mg dose of intravenous morphine, patients allocated to ketamine received a mean of 40.6 mg (SD 25 mg) of ketamine. Patients allocated to morphine alone received a mean of 14.4 mg (SD 9.4 mg) of morphine. The mean pain score change was −5.6 (95% confidence interval [CI] −6.2 to −5.0) in the ketamine group compared with −3.2 (95% CI −3.7 to −2.7) in the morphine group. The difference in mean pain score change was −2.4 (95% CI −3.2 to −1.6) points. The intravenous morphine group had 9 of 65 (14%; 95% CI 6% to 25%) adverse effects reported (most commonly nausea [6/65; 9%]) compared with 27 of 70 (39%; 95% CI 27% to 51%) in the ketamine group (most commonly disorientation [8/70; 11%]). Conclusion Intravenous morphine plus ketamine for out-of-hospital adult trauma patients provides analgesia superior to that of intravenous morphine alone but was associated with an increase in the rate of minor adverse effects.