Therapeutic hypothermia after cardiac arrest: A retrospective comparison of surface and endovascular cooling techniques

Objectives: Therapeutic hypothermia (32-34 degrees C) is recommended for comatose survivors of cardiac arrest; however, the optimal technique for cooling is unknown. We aimed to compare therapeutic hypothermia using either surface or endovascular techniques in terms of efficacy, complications and outcome. Design: Retrospective cohort study. Setting: Thirty-bed teaching hospital intensive care unit (ICU). Patients: All patients (n = 83) undergoing therapeutic hypothermia following cardiac arrest over a 2.5-year period. The mean age was 61 +/- 16 years; 88% of arrests occurred out of hospital, and 64% were ventricular fibrillation/tachycardia. Interventions: Therapeutic hypothermia was initiated in the ICU using iced Hartmann's solution, followed by either surface (n = 41) or endovascular (n = 42) cooling; choice of technique was based upon endovascular device availability. The target temperature was 32-34 degrees C for 12-24h, followed by rewarming at a rate of 0.25 degrees C h(-1). Measurements and main results: Endovascular cooling provided a longer time within the target temperature range (p = 0.02), less temperature fluctuation (p = 0.003), better control during rewarming (0.04), and a lower 48-h temperature load (p = 0.008). Endovascular cooling also produced less cooling-associated complications in terms of both overcooling (p = 0.05) and failure to reach the target temperature (p = 0.04). After adjustment for known confounders, there were no differences in outcome between the groups in terms of ICU or hospital mortality, ventilator free days and neurological outcome. Conclusion: Endovascular cooling provides better temperature management than surface cooling, as well as a more favorable complication profile. The equivalence in outcome suggested by this small study requires confirmation in a randomized trial. (C) 2010 Elsevier Ireland Ltd. All rights reserved.