Study evaluates outcomes of hypothermia treatment among patients with in-hospital cardiac arrest

In a study appearing in the October 4 issue of JAMA, Paul S. Chan, M.D., of Saint Luke's Mid America Heart Institute, Kansas City, and colleagues evaluated the association of hypothermia treatment with survival to hospital discharge and with favorable neurological survival at hospital discharge among patients with in-hospital cardiac arrest.

Therapeutic hypothermia, or targeted temperature management, is recommended for comatose patients following both out-of-hospital and in-hospital cardiac arrest. Nevertheless, therapeutic hypothermia has only been shown to improve overall survival and rates of favorable neurological survival in patients with out-of-hospital cardiac arrest due to ventricular fibrillation. Whether this treatment improves survival for patients with in-hospital cardiac arrest is unknown. As in-hospital cardiac arrest affects approximately 200,000 individuals annually in the United States, there is a need to understand whether therapeutic hypothermia is associated with improved survival for these patients.

With the use of the national Get With the Guidelines-Resuscitation registry, the researchers identified 26,183 patients successfully resuscitated from an in-hospital cardiac arrest between March 2002 and December 2014, and either treated or not treated with hypothermia at 355 U.S. hospitals.

Overall, 1,568 of 26,183 patients with in-hospital cardiac arrest (6 percent) were treated with therapeutic hypothermia; 1,524 of these patients were matched to 3,714 non-hypothermia-treated patients. After adjustment, therapeutic hypothermia was associated with lower in-hospital survival (27.4 percent vs 29.2 percent), and this association was similar for nonshockable cardiac arrest rhythms (22.2 percent vs 24.5 percent) and shockable cardiac arrest rhythms (41.3 percent vs 44.1 percent). Therapeutic hypothermia was also associated with lower rates of favorable neurological survival for the overall study group (hypothermia-treated group, 17 percent; non-hypothermia-treated group, 20.5 percent) and for both rhythm types.

When follow-up was extended to 1 year, there remained no survival advantage with therapeutic hypothermia treatment.

"Collectively, these findings do not support current use of therapeutic hypothermia for patients with in-hospital cardiac arrest," the authors write.

"These observational findings warrant a randomized clinical trial to assess efficacy of therapeutic hypothermia for in-hospital cardiac arrest."