Prehospital plasma administration is associated with increased survival in patients with severe traumatic hemorrhage when in-hospital transfusion is delayed for more than 20 minutes, a retrospective study suggests.

For such patients, the findings suggest that early plasma transfusion is essential and should begin en route to the hospital, Dr. Anthony Pusateri of the U.S. Army Institute of Surgical Research in San Antonio told Reuters Health by email. “The real issue is time from injury,” he noted, “but we were not able to study that directly.”

But, he noted, plasma must be refrigerated, and “this can be a significant logistical challenge, especially for ground ambulance services.”

“A dried plasma product that can be carried on ambulances with minimal storage requirements and easy reconstitution is needed,” he said. “Ideally, this would also be a universal product, not type-specific.”

“Unfortunately, there is not a dried plasma approved for sale in the U.S.,” he added, “even though dried plasmas have been available for many years in other countries.”

Dr. Pusateri and colleagues did a post hoc combined analysis of two randomized trials with apparently contradictory results, both published in 2018. The Prehospital Air Medical Plasma (PAMPer) trial showed a nearly 30 percent reduction in mortality with prehospital plasma transfusion, while the Control of Major Bleeding After Trauma (COMBAT) trial  showed no survival improvement.

The analysis included a total of 626 patients (median age, 42; 75 percent men) from both trials. Patients in hemorrhagic shock were randomly assigned to either standard care (crystalloid-based resuscitation) or two units of thawed plasma followed by standard care in a prehospital setting.

As reported in JAMA Surgery, after adjustment for injury severity, age, and clinical trial cohort (COMBAT or PAMPer), a Cox regression analysis showed a significant overall reduction in 28-day mortality with plasma (hazard ratio, 0.65).

A similar pattern was observed for 24-hour mortality (HR, 0.62). Most deaths in both groups occurred within six hours after injury

A significant association was also seen with prehospital transport time (from arrival on scene to arrival at the trauma center). Specifically, when prehospital transport was longer than 20 minutes, increased mortality was observed in the standard care group, but not in the prehospital plasma group, (HR, 2.12 and 0.78, respectively).

Among patients with short transport times (20 minutes or less), survival did not differ between the groups (HR, 1.71).

No serious adverse events were associated with prehospital plasma.

Dr. Todd Rasmussen of The Uniformed Services University in Bethesda, Maryland, coauthor of a related editorial, commented in an email to Reuters Health, “The study . . . confirms and extends observations of the benefits of blood component transfusions made by the military during the wars in Afghanistan and Iraq.”