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A3360 - Accidental Hypothermia: Nobody Is Dead Until Warm and Dead
Author Block: R. Masroujeh, A. Pandit, A. Syed; Internal Medicine, University Hospitals Cleveland Medical CEnter, Cleveland, OH, United States.
Introduction: Accidental hypothermia is defined by the sudden drop of body core temperature to less than 35°C secondary to cold exposure. While it has significant morbidity and mortality, survivors tend to have excellent neurologic outcomes, justifying prolonged aggressive resuscitation and rewarming. Case Description: A 53 year old woman with unknown medical history at the time was found by EMS “flailing” on the sidewalk on a cold day. She was unresponsive and moaning on her way to the Emergency Department. On arrival, the patient was cold to touch and a crack pipe was identified in her belongings. Pulses were felt in all extremities, and before vital signs could be obtained, the patient developed a witnessed cardiac arrest with the initial rhythm identified as ventricular fibrillation. ACLS protocol was immediately started along with active rewarming via warm IV fluids, forced-air warming, and heat packs. During that period, the patient required 24 cardioversion shocks, epinephrine, amiodarone, lidocaine, and Magnesium sulfate. After 41 minutes, the patient converted to PEA. There was an attempt to stop resuscitation and declare the patient dead, but it was noted that she had upper extremity movements, so ACLS protocol was restarted. After 33 more minutes of resuscitation (total resuscitation time: 74 minutes), ROSC was documented with bradycardia and hypotension. A bladder temperature probe was inserted and showed a core temperature of 25.1°C. The patient was transferred to MICU for continued rewarming and supportive care. She continued to improve and was extubated after 48 hours with full neurologic recovery. After two weeks of hospital stay, she was discharged to a skilled nursing facility for rehabilitation.
Discussion: This case demonstrates the excellent neurologic outcome for patients with accidental hypothermia. Cellular oxygen consumption decreases by 6% for every 1°C drop in temperature. Thus, only 50% of oxygen is needed for a core temperature of 28°C, which can be provided by high-quality CPR. It also demonstrates the resistance to standard treatments of ventricular arrhythmias (DC shocks, epinephrine, and amiodarone) secondary to elevated myocardial excitability and altered drug metabolism. European Resuscitation Council (ERC) suggests limiting subsequent defibrillation and epinephrine doses if initial attempts fail, until core temperature is above 30°C. The final point is to avoid terminating resuscitation efforts prematurely, until adequate rewarming has been achieved to a temperature of 35°C.