A prospective open-label randomised controlled trial in prehospital patients receiving morphine for traumatic pain compared intravenous ketamine with additional morphine.
Analgesia was superior in the ketamine group, with some minor (expected) adverse effects.
This small study adds to the prehospital ketamine literature and provides some support to ambulance services considering introducing ketamine analgesia.

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.

Morphine and Ketamine Is Superior to Morphine Alone for Out-of-Hospital Trauma Analgesia: A Randomized Controlled Trial
Ann Emerg Med. 2012 Jun;59(6):497-503