For patients with severe hypothermia and cardiac arrest, which rewarming approach is indicated?

• A. External warming only
• B. Core rewarming with cardiopulmonary bypass
• C. Immediate defibrillation only
• D. Passive warming

Answer: (B)

When a patient is in severe hypothermia with cardiac arrest, the priority is to raise the core temperature quickly while restoring circulation. Core rewarming with cardiopulmonary bypass does exactly that: it rapidly warms the blood as it circulates through the bypass circuit, delivering warm oxygenated blood to the brain and other organs and supporting perfusion. This approach addresses both the temperature deficit and the need for circulation, which is crucial because at very low temperatures the heart and other tissues respond poorly to conventional resuscitation efforts. External warming or passive warming cannot achieve rapid, adequate core warming during arrest, and defibrillation alone is unlikely to succeed until the core temperature is sufficiently elevated. After warming and stable circulation are established, defibrillation can be considered if a shockable rhythm persists.