Prehospital Use of Ketamine, Morphine, or Fentanyl for the Management of Acute Pain Following Traumatic Injury

Introduction—Ketamine has shown equivalent analgesia when compared to morphine and fentanyl in hospitalized patients.

Objective—To compare the analgesic effects of low-dose ketamine, fentanyl, and morphine in the treatment of acute, traumatic pain in the prehospital setting.

Methods—Using data from the ESO Solutions national database, we performed a retrospective chart review on all 9-1-1 calls answered by 883 EMS agencies between Jan. 5, 2017, and Dec. 31, 2017, in which patients were treated with ketamine, fentanyl, or morphine following traumatic injury. Patients included were greater than 12 years old, had pain of traumatic etiology, an initial pain score of more than 5, at least one subsequent pain score, and administration of either low-dose ketamine, fentanyl, or morphine. Due to poor weight documentation, low-dose ketamine was defined as less than 70 mg parenterally. The primary outcome measure was differences in the proportion of patients in each group with a clinically significant reduction in pain, defined as a decrease of more than 1.3 points on the numeric rating scale. A chi-square test on the binomial proportion of pain reduction was performed and changes in Glasgow Coma Scale, pulse oximetry, end-tidal CO2, systolic blood pressure, heart rate, and respiratory rate following therapy are discussed.

Results—Of 35,906 patients who met inclusion criteria, 28,738 (80.0%) received fentanyl, 6,534 (18.2%) morphine, and 634 (1.8%) ketamine. The following showed a clinically significant reduction in pain: 84.8% in the ketamine group, 85.8% in the fentanyl group, and 83.6% in the morphine group. There was no significant difference in pain when the ketamine group was compared to either the fentanyl group or the morphine group, but fentanyl was associated with clinically significant reduction in pain compared to morphine (p<0.0001). The median single dose of ketamine was 15 mg, fentanyl 50 mcg, and morphine 4 mg.

Conclusion—In the prehospital setting ketamine, compared to fentanyl and morphine, was associated with an equivalent proportion of patients with significant pain reduction. Fentanyl, compared to morphine, was associated with a larger proportion of patients with significant pain reduction. Limitations include an inability to calculate weight-based doses and the possibility of underdosing of morphine.