The PAMPer trial was published in 2018 during an intense focus on prehospital blood product transfusions as a way to limit mortality in civilian trauma patients.1 This multicenter study revealed a 10% decrease in mortality when patients received thawed plasma en route to the trauma center. These results echoed those found in the military experience. At about the same time, the COMBAT trial specifically focused on patients in an urban setting and conversely did not see an improvement in survival with prehospital blood administration.2 The key difference in both of these well-done studies was transport time. Patients enrolled in the PAMPer trial had a median transport time of 41 minutes versus 18 minutes for patients in the COMBAT trial.
The current study offers more data to reinforce the nuanced nature of prehospital blood transfusions and the importance of transport time.3 The authors evaluated their own patients and travel times to postulate how many patients would even be able to benefit from prehospital blood. In this study, only 11% of patients had a travel time long enough to finish a transfusion of a single blood product, using 15 minutes as an estimated time to complete product delivery. While this is an important aspect to consider, time of completion of blood product is likely not as important as time to start of transfusion. Deeb et al evaluated time to early resuscitative intervention and found that for every minute delay, there was a 2% increase in odds of 30-day mortality.4 Perhaps a more useful variable would be time to initiation of transfusion by emergency medical services (EMS) versus the trauma center with estimated time of injury as time zero.
Transport time from the scene is not the only factor in how quickly blood can be initiated. Multiple other variables such as whether or not the EMS unit has blood readily available or if it has to be delivered to them in the field, presence of products within the emergency department of the trauma center, and in the case of plasma, the readiness of that product for transfusion all influence time of transfusion. The decision to transfuse blood products in the field is multifactorial and should be individualized to the patient and situation. If the EMS unit has blood on hand and the patient is in hemorrhagic shock, then early initiation of blood product resuscitation should be started without delay. However, if obtaining blood in the field will delay the transfer of a patient with an otherwise short transfer time, then it does not make sense to do so.
Urban centers typically have shorter travel times, as shown in this study, but that does not mean they do not have a place in prehospital blood programs. A robust prehospital blood program will improve processes and protocols for when the situation is right for prehospital blood. Regular ongoing training and participation create skilled EMS providers who are able to deliver this life-saving care when it is truly needed. From a practical standpoint, participation by urban centers also allows for rotation of blood from more rural EMS units to prevent wastage. When advancing care in the trauma patient population, the needle is moved incrementally. A mature and well-oiled prehospital blood resuscitation machine is just one part of that steady progression toward improved survival.
—Jennifer Mooney, MD
Department of Surgery, Baylor University Medical Center,
Dallas, Texas, USA
Jennifer.Mooney@BSWHealth.org
http://orcid.org/0000-0001-9808-414X
DISCLOSURE STATEMENT
The authors report no funding or conflict of interest.
References
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