Objectives

To observe if patients with severe traumatic injuries evacuated to level 1 trauma centers on air ambulances who received prehospital red blood cells and/or plasma had decreased in-hospital mortality compared to patients who received only crystalloids.

Background

Injury is the leading cause of death in adults and children between the ages of 1 and 44 years. However, approximately 40% of in-hospital deaths among injured patients involve massive truncal hemorrhage that is considered potentially salvageable. Multiple retrospective military and civilian studies have reported that transfusion involving blood component ratios approaching whole blood are associated with significant decreases in 24-hour and 30-day mortality among injured patients. Furthermore, prehospital transfusion (PHT) studies from military and civilian hospitals have shown that prehospital transfusion of plasma and red blood cells (RBCs) is not only feasible, but associated with improved coagulation status on arrival. Prehospital resuscitation practices in the US differ significantly in approach, with most systems using crystalloids while a few offer RBCs or a combination of plasma and RBCs. No large multicenter civilian studies have evaluated the use of prehospital plasma and RBCs in severely injured patients compared to crystalloids.

Participants

Patients estimated to be greater than 15 years old (or greater than 50kg if age unknown) with traumatic injuries, who were transported by helicopter directly from the scene of injury to one of the nine participating Level I trauma centers were eligible for the study. A subset of patients were considered the highest risk population based on at least one of the following criteria measured during prehospital helicopter transport: 1) heart rate greater than 120 beats per minute, 2) systolic blood pressure less than or equal to 90mmHg, 3) penetrating truncal injury, 4) tourniquet applied, 5) pelvic binder applied, 6) intubated prehospital, or 7) received blood products during transport. A total of 25,118 trauma patients were admitted during the 10 month enrollment period to the nine participating centers, of which 2341 arrived by helicopter, and 1058 met the highest risk criteria. Of the high risk sub-set, 585 arrived on helicopters with blood products available and 473 patients arrived via helicopters without blood available. One hundred forty two patients (24%) of those transported on helicopters with blood products available actually received PHT and 916 patients did not.

Design

PROHS was a multicenter, prospective pragmatic, observational study of prehospital resuscitation approaches. There were no study guidelines dictating resuscitation practice (i.e., use of blood products or end of resuscitation). Of the 9 participating Level I trauma centers, 5 had helicopter systems with plasma and/or RBCs while the other 4 had helicopter systems that used only crystalloid resuscitation. All patients arriving to the participating center's trauma emergency department via helicopter directly from the scene were screened and had initial data collected. Of that group, all patients who met the highest risk category or received blood during transport were followed by direct observation during the initial resuscitation period and then indirectly through medical chart review until hospital discharge or 30 days after admission (whichever occurred first).

The primary outcome was in-hospital mortality at 3 hours, 24 hours, and 30 days. Other outcome measures included length of hospital stay, number of ICU days, number of ventilator days, blood product usage, GOSE score at discharge, number of patients with complications, and number of patients who required hemostatic devices.

Conclusions

Because of the unexpected imbalance in injury severity between systems with and without blood products on helicopters, all analyses were inconclusive. With few units transfused to each patient and small outcome differences between groups, large randomized studies will be required to detect significant survival differences in this important population.

Holcomb JB, Swartz MD, DeSantis SM, et al. Multicenter observational prehospital resuscitation on helicopter study. J Trauma Acute Care Surg. 2017;83(1 Suppl 1):S83–S91. doi:10.1097/TA.0000000000001484

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