Association of Opioid Administration During General Anesthesia and Survival for Severely Injured Trauma Patients: A Preplanned Secondary Analysis of the PROPPR Study.

BACKGROUND: There is a lack of reported clinical outcomes after opioid use in acute trauma patients undergoing anesthesia. Data from the Pragmatic, Randomized, Optimal Platelet and Plasma Ratios (PROPPR) study were analyzed to examine opioid dose and mortality. We hypothesized that higher dose opioids during anesthesia were associated with lower mortality in severely injured patients. METHODS: PROPPR examined blood component ratios in 680 bleeding trauma patients at 12 level 1 trauma centers in North America. Subjects undergoing anesthesia for an emergency procedure were identified, and opioid dose was calculated (morphine milligram equivalents [MMEs])/h. After separation of those who received no opioid (group 1), remaining subjects were divided into 4 groups of equal size with low to high opioid dose ranges. A generalized linear mixed model was used to assess impact of opioid dose on mortality (primary outcome, at 6 hours, 24 hours, and 30 days) and secondary morbidity outcomes, controlling for injury type, severity, and shock index as fixed effect factors and site as a random effect factor. RESULTS: Of 680 subjects, 579 had an emergent procedure requiring anesthesia, and 526 had complete anesthesia data. Patients who received any opioid had lower mortality at 6 hours (odds ratios [ORs], 0.02-0.04; [confidence intervals {CIs}, 0.003-0.1]), 24 hours (ORs, 0.01-0.03; [CIs, 0.003-0.09]), and 30 days (ORs, 0.04-0.08; [CIs, 0.01-0.18]) compared to those who received none (all P < .001) after adjusting for fixed effect factors. The lower mortality at 30 days in any opioid dose group persisted after analysis of those patients who survived >24 hours (P < .001). Adjusted analyses demonstrated an association with higher ventilator-associated pneumonia (VAP) incidence in the lowest opioid dose group compared to no opioid (P = .02), and lung complications were lower in the third opioid dose group compared to no opioid in those surviving 24 hours (P = .03). There were no other consistent associations of opioid dose with other morbidity outcomes. CONCLUSIONS: These results suggest that opioid administration during general anesthesia for severely injured patients is associated with improved survival, although the no-opioid group was more severely injured and hemodynamically unstable. Since this was a preplanned post hoc analysis and opioid dose not randomized, prospective studies are required. These findings from a large, multi-institutional study may be relevant to clinical practice.