Timing and location of blood product transfusion and outcomes in massively transfused combat casualties.

Abstract

Hemostatic resuscitation using blood components in a 1:1:1 ratio of platelets:fresh frozen plasma:red blood cells (RBCs) is based on analyses of massive transfusion (MT, ≥10 RBC units in 24 hours). These 24-hour analyses are weakened by survival bias and do not describe the timing and location of transfusions. Mortality outcomes associated with early (first 6 hours) resuscitation incorporating platelets, for combat casualties requiring MT, have not been reported. We analyzed records for 8,618 casualties treated at the United States military hospital in Baghdad, Iraq, between January 2004 and December 2006. Patients (n = 414) requiring MT, not receiving fresh whole blood, and surviving at least 1 hour (reducing survival bias) were divided into 6-hour apheresis platelet (aPLT) transfusion ratio groups: LOW (aPLT:RBC, ≤0.1, n = 344) and HIGH (aPLT:RBC, >0.1, n = 70). Baseline characteristics of groups were compared. Factors influencing survival on univariate analysis were included in Cox proportional hazards models of 24-hour and 30-day survival. Patients received aPLT in the emergency department (4%), operating room (45%), intensive care unit (51%). The HIGH group presented with higher (p < 0.05) admission International Normalized Ratio (1.6 vs. 1.4), base deficit (8 vs. 7), and temperature (36.7 vs. 36.4). Overall mortality was 27%. At 24 hours, the HIGH group showed lower mortality (10.0% vs. 22.1%, p = 0.02). Absolute differences in 30-day mortality were not significant (HIGH, 18.6%; LOW, 28.8%, p = 0.08). On adjusted analysis, the HIGH group was independently associated with increased survival: LOW group mortality hazard ratios were 4.1 at 24 hours and 2.3 at 30 days compared with HIGH group (p = 0.03 for both). Increasing 6-hour FFP:RBC ratio was also independently associated with increased survival. Early (first 6 hours) hemostatic resuscitation incorporating platelets and plasma is associated with improved 24-hour and 30-day survival in combat casualties requiring MT.