Prehospital care is critical to improving outcomes after major trauma

The infrastructure provided by mature trauma systems has facilitated timely delivery of specialized care to the critically injured. What were once universally fatal injuries are now identified and treated rapidly in trauma centres, resulting in increased survival rates. However, opportunities exist to prevent more deaths through the optimization of prehospital care1. The trimodal distribution of death following major trauma, consisting of immediate (within 1 h of injury), early (within hours of injury) and late (within several weeks of injury) deaths, has been replaced in mature trauma systems by a unimodal distribution. The majority of deaths occur in the first several hours after injury, predominantly from haemorrhage and brain injury2. These observations highlight the need to focus on immediate postinjury care. The elimination of immediate and early trauma deaths requires rapid identification of imminently life-threatening injuries, early initiation of blood product resuscitation, and swift deployment of therapeutic interventions. The prehospital component of individual trauma systems is variable, and based on needs and available resources. The overarching objectives of rapidly responding, triaging and transporting the critically injured remain the same. Compliance with existing protocols is critical to delivering the most severely injured to designated trauma centres immediately after injury3. Future trauma systems will employ emerging technologies to expedite the identification of life-threatening injuries. Mobile telephones have already decreased first-responder notification times after injury. Vehicular accident alert and event data recorders have the potential automatically to alert first responders to a collision and provide detailed mechanistic data. Advances in ultrasound technology have made it possible to bring sonography to the prehospital setting, facilitating early identification of life-threatening injuries that are likely to require surgical intervention, and providing an opportunity to alert trauma centres. In this issue of BJS, Sewalt and colleagues4 used the Trauma Audit and Research Network (TARN) to investigate the ability of trauma models to predict mortality and major trauma in the prehospital setting. They found that most perform reasonably well in predicting in-hospital mortality, but are inadequate in identifying patients with major trauma. However, the early recognition of life-threatening haemorrhage in individual patients allows for early initiation of blood product resuscitation. When haemorrhage control cannot be obtained in the prehospital setting, replacing ongoing blood loss during transport to the nearest trauma centre is invaluable. Prehospital massive transfusion prediction scores allow for early mobilization of blood products before arrival in the trauma centre and may determine the appropriateness of blood administration on route. These are important, as every 1-min delay in the arrival of initial blood products after protocol activation increases the mortality rate by 5 per cent5. Two frequently employed and easy-to-use scores are the Shock Index and the Assessment of Blood Consumption (ABC) score. Use of these scores facilitates earlier access to blood component resuscitation and improved mortality6,7. Damage control resuscitation should begin immediately in the field. This concept involves permissive hypotension until surgical control can be achieved, administering a balanced resuscitation of red blood cells, plasma and platelets (in a ratio approximating that of whole blood), while avoiding crystalloids. Prehospital transfusion of plasma in a multicentre RCT8 improved the survival of patients with blood loss compared with that in those receiving crystalloids or red blood cells alone. More recently, low-titre group O whole blood programmes have made their way into the prehospital setting, with improved survival and lower overall blood product requirements9,10. Although life-saving, maintaining access to blood products in the prehospital setting is resource-intensive. Freeze-dried plasma, which can be stored at room temperature with a long shelf-life, eases this burden and is likely to facilitate more widespread availability and administration of prehospital blood products. Controversy exists about the decision to attempt stabilization before or during transport to a trauma centre. However, every trauma system is unique11. In some, particularly where there is rapid access to a major trauma centre, rapid stabilization is inappropriate and may delay definitive care. In others, typically those with longer distances and often requiring air transport, there may be benefit from prehospital intervention, where treatments are administered on route to the trauma centre without delaying definitive care. The application of tourniquets can be performed in seconds in extremity haemorrhage without delay in definitive management. Delaying their application until arrival in trauma centres is associated with increased transfusion requirements and mortality from haemorrhagic shock12. Use of tourniquets may be of benefit regardless of proximity to a trauma centre and the anticipated length of time before definitive care. An international campaign by the American College of Surgeons – ‘Stop the Bleed’ – has been developed to train the general public to recognize life-threatening bleeding and intervene effectively13. Tourniquets can be life-saving in extremity haemorrhage, and pelvic binders may have a place in bleeding from pelvic fractures, but non-compressible haemorrhage remains a significant cause of early mortality. In an attempt to control non-compressible haemorrhage, an increasing number of investigators are evaluating the use of resuscitative endovascular balloon occlusion of the aorta (REBOA) as a tool in the prehospital setting. Analysis of autopsy data of patients with prehospital traumatic cardiac arrest estimated that 10 per cent of patients had non-compressible abdominal or pelvic haemorrhage and may potentially have benefited from prehospital REBOA14. However, successful deployment of REBOA requires training, and is especially challenging in the prehospital environment. The indications for REBOA, and identification of patients who may actually benefit from the procedure, remain to be defined in any setting15. The use of self-expanding polymers is currently being investigated as a potential means of prehospital intracavitary haemostasis in non-compressible haemorrhage. The concept is based on the development of a percutaneously administered, self-expanding polyurethane foam. After introduction into the peritoneal cavity of a patient with haemorrhage via access similar to that of a laparoscopic trocar, the foam would rapidly expand to the fill the volume of the cavity, providing tamponade to any ongoing bleeding. While fatal animal models have shown improved survival with this technique, studies in humans are still under way16. Significant challenges with this concept exist, notably removing the foam at the time of laparotomy to enable swift access to bleeding structures (prolonging surgical haemostasis). To avoid preventable deaths after injury, modern trauma systems should place an increasing emphasis on the prehospital setting. Early identification of life-threatening haemorrhage, initiation of blood product resuscitation, and minimization of blood loss in the prehospital setting are key and have the potential to reduce the considerable burden of downstream physiological derangements that result in multiple organ dysfunction17. The authors declare no conflict of interest.