Effect of Prehospital Induction of Mild Hypothermia on 3‐Month Neurological Status and 1‐Year Survival Among Adults With Cardiac Arrest: Long‐Term Follow‐up of a Randomized, Clinical Trial

BACKGROUND Randomized trials of prehospital cooling after cardiac arrest have shown that neither prehospital cooling nor targeted temperature management differentially affected short-term survival or neurological function. In this follow-up study, we assess the association of prehospital hypothermia with neurological function at least 3 months after cardiac arrest and survival 1 year after cardiac arrest. METHODS AND RESULTS There were 508 individuals who were discharged alive from hospitals in King County, Washington; 373 (73%) were interviewed by telephone 123±43 days after the initial event. Overall, 59% of the treatment group and 58% of the control group had Cerebral Performance Category (CPC) 1 or 2 (P=0.70), and 50% of the treatment group and 49% of the control group had slight disability or better by the Modified Rankin Scale (MRS; (P=0.35). One-year survival was 87% in the treatment group and 84% in the control group (P=0.42). Of those with CPC 1 at hospital discharge, 68% had CPC 1 or 2 at follow-up, and 59% had MRS of slight disability or better. Of 41 patients with CPC 3 or 4 at discharge, only 12% had CPC 2 at follow-up, and just 5% had MRS of slight disability or better. One-year survival was 92% for CPC 1 at discharge, but only 40% for CPC 4. CONCLUSION In addition to excellent survival, patients who had good neurological function at discharge continued to have good function at least 3 months after the event. CLINICAL TRIAL REGISTRATION URL: Clinicaltrials.gov. Unique identifier: NCT00391469.