Prehospital Transfusion of Red Blood Cells and Plasma by an Urban Ground-Based Critical Care Team

Pre-Hospital Blood Products for the Care of Bleeding Trauma Patients

BACKGROUND

Controversy surrounds the administration of blood products to severely traumatized patients before they arrive in the hospital in order to compensate for early blood loss and/or to correct coagulation disturbances that arise shortly after the traumatic event. A number of terrestrial and air rescue services have begun to provide this kind of treatment.

METHODS

This review is based on articles using the PICO framework, published from January 2001 to January 2021, that were retrieved by a selective search, with structured searching strategies and searching bundles in Medline (OVIDSP), the Cochrane Central Register of Controlled Trials (CENTRAL), and Epistemonikos. A demand analysis was carried out on the basis of data from the trauma registry of the German Society of Trauma Surgery (TR-DGU) and practical experience from program development and implementation was provided by the Bundeswehr Hospital Ulm.

RESULTS

The currently available evidence on the pre-hospital administration of blood products in the early treatment of severely injured patients is based largely on retrospective, single-center case series. Two randomized controlled trials (RCTs) concerning the early use of fresh frozen plasma concentrates have yielded partly conflicting results. Three further RCTs on the use of lyophilized plasma (lyplas), lyplas plus erythrocyte concentrate, or whole blood likewise revealed non-uniform effects on short-term and intermediate-term mortality. Our demand analysis based on data from the TR-DGU showed that 300 to 1800 patients per year in Germany could benefit from the pre-hospital administration of blood products. This might be indicated in patients who have systolic hypotension (<100 mmHg) in combination with a suspected or confirmed hemorrhage, as well as pathological shock parameters in the point-of-care diagnostic testing performed on the scene (serum base excess ≤ -2.5 mmol/L and/or serum lactate concentration >4 mmol/L).

CONCLUSION

The studies that have been published to date yield no clear evidence either for or against the early pre-hospital administration of blood products. Any treatment of this kind should be accompanied by scientific evaluation.

Development of a national out-of-hospital transfusion protocol: a modified RAND Delphi study

BACKGROUND

Early resuscitation with blood components or products is emerging as best practice in selected patients with trauma and medical patients; as a result, out-of-hospital transfusion (OHT) programs are being developed based on limited and often conflicting evidence. This study aimed to provide guidance to Canadian critical care transport organizations on the development of OHT protocols.

METHODS

The study period was July 2021 to June 2022. We used a modified RAND Delphi process to achieve consensus on statements created by the study team guiding various aspects of OHT in the context of critical care transport. Purposive sampling ensured representative distribution of participants in regard to geography and relevant clinical specialties. We conducted 2 written survey Delphi rounds, followed by a virtual panel discussion (round 3). Consensus was defined as a median score of at least 6 on a Likert scale ranging from 1 ("Definitely should not include") to 7 ("Definitely should include"). Statements that did not achieve consensus in the first 2 rounds were discussed and voted on during the panel discussion.

RESULTS

Seventeen subject experts participated in the study, all of whom completed the 3 Delphi rounds. After the study process was completed, a total of 39 statements were agreed on, covering the following domains: general oversight and clinical governance, storage and transport of blood components and products, initiation of OHT, types of blood components and products, delivery and monitoring of OHT, indications for and use of hemostatic adjuncts, and resuscitation targets of OHT.

INTERPRETATION

This expert consensus document provides guidance on OHT best practices. The consensus statements should support efficient and safe OHT in national and international critical care transport programs.

The Role of Plasma Transfusion in Pre-Hospital Haemostatic Resuscitation

Traumatic haemorrhage remains a major cause of preventable death and early haemostatic resuscitation is now a mainstay of treatment internationally. Recently, 2 randomized control trials (RCTs) - PAMPer (Prehospital Air Medical Plasma) and COMBAT (Control of Major Bleeding After Trauma), evaluating the effect of pre-hospital use of plasma on mortality provided conflicting results, raising important questions on the role of plasma resuscitation in pre-hospital environment. Both PAMPer (n = 501 patients) and COMBAT (n = 144 patients) trials were pragmatic RCTs that evaluated the effect of pre-hospital plasma transfusion (two units) versus standard of care on 28/30 days mortality in trauma patients who presented with clinical signs of haemorrhagic shock (defined as hypotension or tachycardia). The PAMPer trial showed that plasma transfusion reduced 30-day mortality compared with standard of care (23% vs 33%, 95% confidence interval -18.6; -1.0%; P = 0.03), while COMBAT trial showed no difference in 28-day survival. The post-hoc analyses of the 2 trials have suggested that the benefit of pre-hospital plasma transfusion may be greater for patients who are coagulopathic, have blunt injury and have a transport time from the scene of injury to the hospital of >20 minutes. In this review we evaluate strengths and limitations of the two trials and their differences and similarities, which may explain the conflicting results, as well as provide directions for future trials to better define the target population that would most benefit from pre-hospital plasma resuscitation. Further, considering the logistical challenges of carrying any blood components on an aircraft, cost/safety of plasma, and the scarcity of universal blood group donors, there is a need for a health economic evaluation of pre-hospital plasma transfusion in trauma patients, prior to this intervention becoming universal.