Therapeutic Hypothermia After Resuscitation From a Non-Shockable Rhythm Improves Outcomes in a Regionalized System of Cardiac Arrest Care

Objective Therapeutic hypothermia (TH) improves neurologic outcome in patients resuscitated from ventricular fibrillation. The purpose of this study was to evaluate TH effects on neurologic outcome in patients resuscitated from a non-shockable out-of-hospital cardiac arrest rhythm. Design and Setting This is a retrospective cohort study of data reported to a registry in an emergency medical system in a large metropolitan region. Patients achieving field return of spontaneous circulation are transported to designated hospitals with TH protocols. Patients Patients with an initial non-shockable rhythm were identified.Patients were excluded if awake in the Emergency Department or if TH was withheld due to preexisting coma or death prior to initiation. The decision to initiate TH was determined by the treating physician. Measurements The primary outcome was survival with good neurologic outcome defined by a cerebral performance category of 1 or 2. Main Results Of the 2772 patients treated for cardiac arrest during the study period, there were 1713 patients resuscitated from cardiac arrest with an initial non-shockable rhythm and 1432 patients met inclusion criteria. The median age was 69 years [IQR 59-82]; 802 (56 %) male. TH was induced in 596 (42 %) patients. Survival with good neurologic outcome was 14 % in the group receiving TH, compared with 5 % in those not treated with TH (risk difference = 8 %, 95 % CI 5-12 %). The adjusted OR for a CPC 1 or 2 with TH was 2.9 (95 % CI 1.9-4.4). Conclusion Analyzing the data collected from the registry of the standard practice in a large metropolitan region, TH is associated with improved neurologic outcome in patients resuscitated from initial non-shockable rhythms in a regionalized system for post-resuscitation care.