The use of whole blood in traumatic bleeding: a systematic review

Hemostatic resuscitation is currently considered a standard of care for the management of life-threatening hemorrhage, but in some critical settings the access to high quantities of blood components is problematic. Whole blood (WB) transfusion has been proposed as an alternative modality for hemostatic resuscitation of traumatic major bleeding. To assess the efficacy and safety of WB in trauma-associated massive bleeding, we performed a systematic review of the literature. We selected studies comparing WB transfusions to transfusion of blood components (COMP) in massive trauma bleeding; both randomized clinical trial (RCT) and observational studies were considered. The outcomes were mortality (30-day/in-hospital and 24-h mortality) and adverse events/transfusion reactions. The effect sizes were crude odds ratio (OR), adjusted OR and hazard ratio (HR). The methodological quality of studies was assessed using the Cochrane Risk of Bias tool for RCTs, and the ROBIN-1 tool for observational studies. The overall quality of the available evidence was assessed with the GRADE system. One RCT (2 reports) and 6 cohort studies were included (3642 adult patients; 675 receiving WB, 2967 receiving COMP). Three studies were conducted in military setting, and 4 in civilian setting. In the overall analysis, 30-day/in-hospital and 24-h mortality did not differ significantly between groups (very low quality of the evidence due to high risk of bias, imprecision and inconsistency). After adjustment for baseline covariates in three cohort studies, the OR for mortality was significantly lower in WB recipients compared to COMP (OR 0.22; 95% CIs 0.10/0.45) (moderate grade of evidence). Adverse events and transfusion reactions were overlooked and not consistently reported. The available evidence does not allow to draw definite conclusions on the short-term and long-term efficacy and safety of WB transfusion compared to COMP transfusion. Further well designed research is needed.