Whole blood first resuscitation and association of blood product utilization based on mechanism of injury

INTRODUCTION: Studies evaluating the effect of whole blood (WB) vs. component-based resuscitation accounting for mechanism of injury are lacking. We sought to evaluate the effects of a WB first resuscitation strategy regarding mechanism of injury. METHODS: This is a retrospective cohort study of trauma patients who received any blood product during resuscitation from January 2016 to November 2021. The primary outcomes were total blood volume utilized within 24 h and 30-day mortality. Multivariable gamma regression with a log link was used for blood volume and logistic regression for mortality. A likelihood ratio test evaluated whether injury mechanism modified the treatment effect. RESULTS: Between January 2016 and November 2021, 1,013 injured patients received blood products (785 WB-first). We did not detect statistically significant effect modification by injury mechanism for either outcome (interaction p = 0.44 for blood volume, p = 0.25 for mortality). In multivariable gamma regression, WB-first resuscitation was associated with a ratio of mean total blood volume of 0.71 (95% CI 0.55 to 0.90, p = 0.005) relative to components, representing approximately 29% lower utilization. WB-first was not associated with 30-day mortality (OR 0.90, 95% CI 0.48 to 1.71, p = 0.73). CONCLUSIONS: A WB-first resuscitation strategy is associated with lower blood volume utilized within the first 24 h, without statistically significant effect modification by injury mechanism (though clinically meaningful mechanism-specific differences cannot be excluded). The mortality estimate was non-significant across all analytic approaches but varied in direction (OR 0.66 to 1.48) and was sensitive to handling of approximately 30% of patients with incomplete laboratory data. Further studies are needed to determine which populations most benefit from WB-based resuscitation.