The chain of survival in hypothermic circulatory arrest: encouraging preliminary results when using early identification, risk stratification and extracorporeal rewarming

BACKGROUND: The prognosis in hypothermic cardiac arrest is frequently good despite prolonged period of hypoperfusion and cardiopulmonary resuscitation. Apart from protective effect of hypothermia itself established protocols of treatment and novel rewarming techniques may influence on outcome. The purpose of the study was to assess the outcome of patients with hypothermic circulatory arrest treated by means of arterio-venous extracorporeal membrane oxygenation (ECMO) according to locally elaborated protocol in Severe Accidental Hypothermia Center in Cracow, Poland. METHODS: Prospective observational case-series study – all patients with confirmed hypothermic cardiac arrest consulted with hypothermia coordinator were accepted for extracorporeal rewarming, unless contraindications for ECMO were observed (active bleeding). RESULTS: The study population consisted of 10 patients (7 male, median age 48.5 years). The core temperature measured esophageally was 16.9–28.4 °C, median 22 °C. On admission 5 patients presented with asystole and 5 with ventricular fibrillation. Duration of circulatory arrest before ECMO implantation was 107 to 345 min (median 156 min). The duration of ECMO support was 1.5 to 91 h (median 22 h). Cardiorespiratory stability and full neurologic recovery was achieved in 7 patients. The duration of mechanical ventilation was 88–437 h (median 177 h) and the length of stay in the ICU was 8–26 days (median 15 days). All survivors had mildly impaired (1 patient, LVEF 40 %) or preserved (6 patients, LVEF 55–65 %) left ventricular systolic function at the time of discharge from ICU. The cause of death of non-survivors (three patients) was acute myocarditis, massive retroperitoneal bleeding, and massive gastrointestinal bleeding. DISCUSSION AND CONCLUSIONS: Our data confirm the high survival rate (70 %) and excellent neurologic outcome in hypothermic cardiac arrest. The following key elements seem to impact the final prognosis: the appropriate coordination of the rescue operation, immediate high-quality CPR (preferably using mechanical chest compression system) and application of ECMO for rewarming and cardiorespiratory support.