Optimal Prehospital Crystalloid Resuscitation Volume in Trauma Patients at Risk for Hemorrhagic Shock.

ABSTRACT

BACKGROUND: Prehospital resuscitation guidelines vary widely, and blood products, although likely superior, are not available for most patients in the prehospital setting. Our objective was to determine the prehospital crystalloid volume associated with the lowest mortality among patients in hemorrhagic shock. STUDY DESIGN: This is a secondary analysis of the Prehospital Air Medical Plasma trial. Injured patients from the scene with hypotension and tachycardia or severe hypotension were included. Segmented regression and generalized additive models were used to evaluate nonlinear effects of prehospital crystalloid volume on 24-hour mortality. Logistic regression evaluated the association between risk-adjusted mortality and prehospital crystalloid volume ranges to identify optimal target volumes. Inverse propensity weighting was performed to account for patient heterogeneity. RESULTS: There were 405 patients included. Segmented regression suggested the nadir of 24-hour mortality lay within 377 to 1,419 mL prehospital crystalloid. Generalized additive models suggested the nadir of 24-hour mortality lay within 242 to 1,333 mL prehospital crystalloid. A clinically operationalized range of 250 to 1,250 mL was selected based on these findings. Odds of 24-hour mortality were higher for patients receiving less than 250 mL (adjusted odds ratio [aOR] 2.46; 95% CI 1.31 to 4.83; p = 0.007) and greater than 1,250 mL (aOR 2.57; 95% CI 1.24 to 5.45; p = 0.012) compared with 250 to 1,250 mL. Propensity-weighted regression similarly demonstrated odds of 24-hour mortality were higher for patients receiving less than 250 mL (aOR 2.62; 95% CI 1.34 to 5.12; p = 0.005) and greater than 1,250 mL (aOR 2.93; 95% CI 1.36 to 6.29; p = 0.006) compared with 250 to 1,250 mL. CONCLUSIONS: Prehospital crystalloid volumes between 250 and 1,250 mL are associated with lower mortality compared with lower or higher volumes. Further work to validate these finding may provide practical volume targets for prehospital crystalloid resuscitation.