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

Abstract

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. 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 (GAM) were used to evaluate non-linear 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. There were 405 patients included. Segmented regression suggested the nadir of 24-hour mortality lay within 377-1419mL of prehospital crystalloid. GAM suggested the nadir of 24-hour mortality lay within 242-1333mL of prehospital crystalloid. A clinically operationalized range of 250-1250mL was selected based on these findings. Odds of 24-hour mortality were higher for patients receiving <250mL (aOR 2.46; 95%CI 1.31-4.83, p=0.007) and >1250mL (aOR 2.57; 95%CI 1.24-5.45, p=0.012) compared to 250-1250mL. Propensity weighted regression similarly demonstrated odds of 24-hour mortality were higher for patients receiving <250mL (aOR 2.62; 95%CI 1.34-5.12, p=0.005) and >1250mL (aOR 2.93; 95%CI 1.36-6.29, p=0.006) compared to 250-1250mL. Prehospital crystalloid volumes between 250-1250mL are associated with lower mortality compared to lower or higher volumes. Further work to validate these finding may provide practical volume targets for prehospital crystalloid resuscitation.