Therapeutic Hypothermia May Improve Neurological Outcomes in Extracorporeal Life Support for Adult Cardiac Arrest

Background: Limited data exists on patients receiving therapeutic hypothermia during extracorporeal life support (ECLS). We investigated outcomes and prognostic factors in these patients.

Methods: A retrospective review was conducted for 225 consecutive adult patients treated with ECLS between July 2003 and January 2016. Extracorporeal life support was initiated for refractory cardiac arrest (>10 mins) in 79 patients (35.1%). Patient demographics, ECLS-related complications, in-hospital mortality and neurological outcomes were analysed.

Results: The mean age was 49.9±12.4 years. Sixty-two patients (78.5%) were male. The mean duration of CPR and ECLS were respectively, 32.0±23.3 mins and 5.4±4.0 days. Therapeutic hypothermia (34^oC) was maintained for 24hours in 14 patients (17.7%). Thirty-five patients (44.3%) were weaned off ECLS. Twenty-one patients (26.6%) survived to hospital discharge with 16 (20.3%) recovering good neurological function. Compared to ECLS at normothermia, neurologically favourable survival was higher in the hypothermia group (42.9% vs 15.4%, p=0.020). Multivariable analysis identified a non-shockable rhythm [odds ratio (OR) 5.1, confidence interval (CI) 1.5-16.8], ischaemic hepatitis (OR 6.2, CI 1.1-33.6) and hypoxic ischaemic encephalopathy (OR 5.1, CI 1.5-17.1) as predictors of in-hospital mortality. Therapeutic hypothermia (OR 4.9, CI 1.2-20.4) and acute renal failure (OR 0.19, CI 0.05-0.70) were predictors of neurologically favourable survival.

Conclusions: In this report of patients treated with ECLS, in-hospital survival and survival with good neurological performance were 26.6% and 20.3% respectively. A non-shockable rhythm, ischaemic hepatitis and hypoxic ischaemic encephalopathy were predictors of in-hospital mortality. Therapeutic hypothermia during ECLS was associated with improved neurological outcomes.