The initial treatment of the trauma patient in extremis presents a clinical, logistical, and sometimes ethical challenge. The patient’s physiology and clinical presentation should guide the immediate work-up and treatment. While emergency cardiothoracic surgery is ideally conducted in the operating room, traumatic cardiac arrest may mandate an immediate emergency department thoracotomy (EDT). The decision to perform EDT must balance the chance of meaningful survival, the risk of poor neurologic outcome, the hazard due to occupational exposure, and the consideration for human dignity at the end of life. EDT enables rapid thoracic hemorrhage control, release of pericardial tamponade, aortic cross clamping, and the ability to perform open cardiac massage to increase perfusion. To maximize survival, EDT must be performed in conjunction with balanced blood product transfusion and rapid transport to the operating room for definitive surgery.