Hypothermic cardiac arrest: prognostic factors for successful resuscitation before rewarming

To indicate factors predicting return of spontaneous circulation in patients with hypothermic cardiac arrest in the pre-rewarming period.

A multicenter retrospective study was conducted. We included patients who had suffered cardiac arrest caused by severe accidental hypothermia with a core body temperature of ≤ 28 °C. Patients who had achieved return of spontaneous circulation before commencement of active rewarming at the hospital were compared to those who remained in cardiac arrest.

A total of 156 patients suffering hypothermic cardiac arrest were included in the study. In 14 of them (9%) resuscitation was successful before rewarming. Factors associated with return of spontaneous circulation were as follows: witnessed onset of cardiac arrest (p = 0.04); a higher core body temperature (p = 0.005) with a prognostic threshold of 24.6 °C; and a higher arterial oxygen partial pressure (p = 0.04) with a prognostic threshold of 81 mmHg. One patient after successful resuscitation sustained recurrence of cardiac arrest during rewarming.

Patients with core body temperature < 25 °C, hypoxemia, and those who sustained unwitnessed hypothermic cardiac arrest have weak chances for successful resuscitation before rewarming. They can benefit from immediate transportation to an extracorporeal life support facility under continuous cardiopulmonary resuscitation. Effective rewarming and oxygenation during the prehospital period can increase the chances for return of spontaneous circulation. Recurrence of cardiac arrest during rewarming is uncommon.