As with any snapshot of evidence, this remains only a piece of the puzzle with respect to the utility of prehospital blood products in trauma. These authors do not parse out specific causes of death, and generally most patients were not yet in hemorrhagic shock on arrival at the hospital. This is presumably linked to the short transport times involved from the scene to definitive care, reducing the likelihood of exsanguination prior to hospital arrival.

The RePHILL trial fits in with other trials of prehospital plasma or prehospital blood products. It informs resource management for urban prehospital systems with short transport times. Replacing blood with blood has obvious face validity, but many other clinical scenarios have found conservative transfusion thresholds are not harmful. Early in the course of traumatic hemorrhage, with prehospital shock but substantial remaining reserve, aggressive early use of blood products may not be providing the hoped-for survival advantage. Future trials ought to illuminate at which point the resuscitation can switch from crystalloid to blood products.

Dr. Radecki is an emergency physician and informatician with Christchurch Hospital in Christchurch, New Zealand. He is the Annals of Emergency Medicine podcast co-host and Journal Club editor and can be found on Twitter @emlitofnote.

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