Abstract 18393: Survival after Post-Arrest Therapeutic Hypothermia: Secondary Analysis of The Strategies for Post-Arrest Care (SPARC) Stepped-Wedge Trial
Introduction: Current guidelines recommend early institution of therapeutic hypothermia (TH) in survivors of out of hospital cardiac arrest (OHCA) regardless of initial rhythm. This was based on trials employing concurrent or historical controls since the original randomized trials restricted the analysis to OHCA presenting with ventricular fibrillation (VF) or ventricular tachycardia (VT). We sought to measure the survival of patients after application of these recommended guidelines during a stepped-wedge randomized trial that compared KT strategies to improve TH in a network of 36 hospitals.
Methods: After a baseline period of 12 months, 4 wedges of 8 to 10 hospitals were randomized to receive 12 months of passive KT followed by 4 months of active KT. We measured the secondary outcome of survival to hospital discharge in patients that had received therapeutic hypothermia. We used multilevel modeling to calculate odds ratios (OR) for survival after adjusting for time and the Utstein factors.
Results: During the study, 4,742 OHCA patients were transported to hospital; 1,963 (39%) achieved ROSC and 1,104 (56%) of these were eligible for TH. 638 (58%) of the eligible patients had cooling initiated and 223 (35%) were cooled to 34 degrees within 6 hours. No survival advantage of cooling was observed for all eligible patients (cooling ever vs never, OR adjusted for time only 1.04, 95% CI 0.74-1.47; OR adjusted for prehospital variables (Utstein) 0.80, 95% CI 0.53-1.20). Similar findings were observed when the analyses were restricted to the 516 eligible patients that presented with VF/VT (OR adjusted for time only 0.74, 95% CI 0.44-1.24; OR adjusted for Utstein variables 0.84, 95% CI 0.52-1.37).
Conclusions: During a stepped wedge knowledge translation randomized trial, we were unable to confirm the survival advantage associated with cooling after OHCA.
- © 2011 by American Heart Association, Inc.