This patient is hemodynamically unstable as a result of severe accidental hypothermia and should undergo extracorporeal rewarming to maximize the rate of temperature correction. Passive external rewarming (blankets, insulation) and active external rewarming (heating pads, radiant heat) are used for mild or moderate hypothermia. However, this patient has severe hypothermia with hemodynamic instability, and more aggressive warming techniques are indicated. In this case, extracorporeal support, including cardiopulmonary bypass, is recommended because it maximizes the rewarming rate and can also provide hemodynamic support. Cardiopulmonary bypass, most frequently used in cardiac surgical procedures, can provide hemodynamic stabilization and can increase the body temperature by approximately 9.0 °C (16.2 °F) per hour.

Other forms of active internal warming, such as administering warmed intravenous fluids or intraperitoneal and pleural irrigation, are indicated for severe hypothermia, as in this patient. However, these methods do not provide hemodynamic support and do not raise body temperature as rapidly as cardiopulmonary bypass. For example, 1 L of fluid at 42.0 °C (107.6 °F) would raise this patient's core temperature by approximately 0.25 °C (0.45 °F).

This patient is at risk of developing hypothermia-related sustained ventricular tachycardia and fibrillation, but limited data indicate that core temperatures greater than 34.0 °C (93.2 °F) are needed for pharmacologic therapies such as lidocaine to be effective. Additionally, electrical cardioversion is often ineffective in patients with core temperatures less than 30.0 °C (86.0 °F). Rewarming is the surest method of stabilizing this patient, and attempts at treating or preventing arrhythmias should not detract from this.

Although this patient's clinical presentation is concerning for potential severe anoxic encephalopathy, there are numerous reports of survival with good neurologic outcomes in patients with hypothermia requiring prolonged periods of cardiopulmonary resuscitation. The neurologic examination is not reliable in assessing neurologic injury in severe hypothermia. Given the potential for recovery, recommending no CPR in the event of recurrent nonperfusing cardiac rhythm is not the best option for this patient.