Introduction

• Establishing the cause of cardiac arrest may not be straightforward. A primary medical arrest can occur before a patient suffers a secondary traumatic insult. Primary medical cardiac arrests resulting in falls from height or while driving are examples that can typically result in rescuers suspecting cardiac arrest of traumatic origin.

• Pay close attention to a witness's history and perform an accurate scene assessment to establish the course of events and mechanism of injury. If there is a possibility that the patient has had a primary medical cardiac arrest, follow standard BLS and ALS guidelines. Where trauma is considered to be the primary cause of the arrest, consider early enhanced care support and follow the traumatic cardiac arrest algorithm

• Patients who are in cardiac arrest following drowning, hanging or asphyxiation should not automatically be conveyed to a major trauma centre (MTC) (unless there is a significant mechanism to trigger TU bypass). However, all patients for whom ROSC has been achieved following traumatic cardiac arrest should be conveyed to an MTC unless airway and/or catastrophic haemorrhage cannot be safely managed when a pit stop at the nearest Emergency Department is indicated.

• Consider termination of the resuscitative effort if the patient presents in asystole and has not responded to 15 minutes of ALS with likely reversible causes treated successfully. The exceptions to termination at 15 minutes are for pregnancy, children and where hypothermia may be a contributory factor.

Blunt Trauma

• In the pre-hospital setting, advanced life support and exclusion of reversible causes using the 4Hs and 4Ts or the HOT approach should take priority. The commonest causes of traumatic cardiac arrest are hypovolaemia, oxygenation (hypoxia) and tension pneumothorax, which form the mnemonic ‘HOT’ – a helpful short checklist of reversible causes for the management of these patients.

• Rapid treatment of reversible causes should take priority over chest compressions and ALS drug administration. However, high-quality chest compressions are important and may generate some forward flow, even in cases of severe hypovolaemia or cardiac tamponade; it is, therefore, important to continue chest compressions as soon as sufficient personnel are available to allocate someone to this task.

• Undertake only essential lifesaving interventions on scene. If the patient has signs of life (pulse, chest rise, breathing efforts, movements, eye opening or shockable rhythm), rapidly transfer to the hospital or arrange rendezvous with enhanced/critical care support. Do not delay for spinal immobilisation.

• Effective airway management using a stepwise approach is essential to maintain oxygenation of the severely compromised trauma patient. In low cardiac output conditions, positive pressure ventilation may cause further circulatory depression or even cardiac arrest by impeding venous return to the heart. Monitor ventilation with continuous waveform capnography and adjust the rate to achieve normocarbia.

• Consider performing all further interventions en route and administering tranexamic acid early. 

• Hypovolaemia due to blood loss that is sufficient in volume to cause cardiac arrest is difficult to treat. Gain large bore IV access. Although IV normal saline may restore blood volume (often requiring 2–3 litres). Request enhanced care, particularly if it enables blood and blood products to be brought to scene without delay. Once ROSC is achieved, only give IV fluids to achieve a systolic BP no higher than 80 mmHg.

• In blunt trauma cases, where ALS (including attempts to address reversible causes) is being delivered, clinical judgment may be applied as to whether enhanced care assets may be accessed, or the patient can be conveyed to an MTC (or TU if necessary) in a timely manner. If likely reversible causes of traumatic cardiac arrest have been treated and there has been no ROSC after 15 minutes of ALS, resuscitation may stop.

Penetrating Trauma

• In penetrating traumatic cardiac arrest, patients should be transferred rapidly to a hospital because surgical intervention is often needed to treat the cause of the arrest. A rapid transport approach is appropriate to the nearest MTU (or TU if necessary), but crew safety should be a consideration where there are prolonged journey times in a moving vehicle.

• Enhanced care assets should be requested early for attendance at the scene (but do not delay departure from scene while waiting for these assets) and/or during conveyance.

• Rapidly address immediate issues:

  • catastrophic haemorrhage (splinting, trauma dressings, tourniquet etc.)

  • airway and breathing (consider tension pneumothorax, sucking chest wound etc.)

  • defibrillation, if indicated.

  • Consider performing all further interventions en-route and administer tranexamic acid early.

• The principles for volume resuscitation for penetrating trauma are similar to those for blunt trauma. However, the priority for rapid conveyance to the hospital often precludes any significant pre-hospital volume being administered. Do not delay on scene to obtain IV access. If IV fluids are administered, a systolic BP no greater than 80 mmHg is adequate. Surgical intervention is often the only intervention that will save the patient’s life, and rapid conveyance to a hospital is vital to achieve this.