Is Prehospital Ketamine Associated With a Change in the Prognosis of PTSD?

Abstract

Ketamine is an alternative to opioids for prehospital analgesia following serious combat injury. Limited research has examined prehospital ketamine use, associated injuries including traumatic brain injury (TBI) and PTSD outcomes following serious combat injury. We randomly selected 398 U.S. service members from the Expeditionary Medical Encounter Database who sustained serious combat injuries in Iraq and Afghanistan, 2010-2013. Of these 398 patients, 213 individuals had charted prehospital medications. Clinicians reviewed casualty records to identify injuries and all medications administered. Outcomes were PTSD diagnoses during the first year and during the first 2 years postinjury extracted from military health databases. We compared PTSD outcomes for patients treated with either (a) prehospital ketamine (with or without opioids) or (b) prehospital opioids (without ketamine). Fewer patients received prehospital ketamine (26%, 56 of 213) than only prehospital opioids (69%, 146 of 213) (5%, 11 of 213 received neither ketamine nor opioids). The ketamine group averaged significantly more moderate-to-serious injuries, particularly lower limb amputations and open wounds, compared with the opioid group (Ps < .05). Multivariable regressions showed a significant interaction between prehospital ketamine (versus opioids) and TBI on first-year PTSD (P = .027). In subsequent comparisons, the prehospital ketamine group had significantly lower odds of first-year PTSD (OR = 0.08, 95% CI [0.01, 0.71], P = .023) versus prehospital opioids only among patients who did not sustain TBI. We also report results from separate analyses of PTSD outcomes among patients treated with different prehospital opioids only (without ketamine), either morphine or fentanyl. The present results showed that patients treated with prehospital ketamine had significantly lower odds of PTSD during the first year postinjury only among patients who did not sustain TBI. These findings can inform combat casualty care guidelines for use of prehospital ketamine and opioid analgesics following serious combat injury.