All massive transfusion criteria are not created equal: defining the predictive value of individual transfusion triggers to better determine who benefits from blood.

BACKGROUND: As familiarity with military massive transfusion (MT) triggers has increased, there is a growing interest in applying these in the civilian population to initiate MT protocols (MTP) earlier. We hypothesize that these triggers do not have equal predictability for MT and understanding the contribution of each would improve our ability to initiate the MTP earlier.
METHODS: All patients presenting to a Level I trauma center from October 2007 to September 2008 requiring immediate operation were included in this study. Emergency department records, operative logs, and blood transfusion data from arrival to procedure end were analyzed using multivariate regression techniques. Triggers included systolic blood pressure (SBP) <90 mm Hg, hemoglobin <11 g/dL, temperature <35.5°C, International normalized ratio (INR) >1.5, and base deficit ≥6.
RESULTS: One hundred seventy patients required immediate operation with an overall survival of 91%. Transfusion of packed red blood cells was noted in 45% (77 of 170) with the mean number of transfused units highest in those meeting SBP (12.9 Units) or INR (12.3 Units) triggers. The triggers do not contribute equal predictive value for the need for transfusion with INR being the most predictive (odds ratio, 16.7; 95% confidence interval, 2-137) for any transfusion and highly predictive for the need for MT (odds ratio, 11.3; 95% confidence interval, 3-47). In fact, if patients met either INR or SBP triggers alone, they were likely to receive MT (p = 0.018 and 0.003, respectively).
CONCLUSION: Triggers have differential predictive values for need for transfusion. Defining the individual utility of each criterion will help to identify those most likely to benefit from an early initiation of the MTP.