In Reply Although a retrospective study cannot rule out unmeasured confounding, we respectfully disagree with Dr David and colleagues that the reported between-group mortality difference “may be related to the quality of prehospital resuscitation rather than prehospital transfusion.”
Short transport times (median, 17 minutes) may explain why most prehospital transfusion recipients received only 1 U of red blood cells or plasma. The time to initiate first transfusion was strongly associated with survival, and the study’s finding that all 55 recipients survived to continue transfusions in the hospital may be its most valuable.