Effect of Therapeutic Hypothermia on Survival and Neurologic Outcome in the Elderly

Old age is considered a negative prognostic factor after out-of-hospital cardiac arrest (OHCA). The purpose of this study was to assess the benefit of therapeutic hypothermia (TH) on survival and neurologic outcome in the elderly. This is a retrospective study of patients treated for OHCA from April 2011 to August 2013 in a regional cardiac system. Patients with return of spontaneous circulation (ROSC) are directed to designated cardiac receiving centers with established TH protocols. The decision to initiate TH is determined by the treating physician. All patients 65 years or older were identified. Patients were excluded if awake and responsive in the emergency department, died before hospital admission, or had preexisting coma. The adjusted odds ratio for survival with good neurologic outcome (defined as cerebral performance category [CPC] 1 or 2) was calculated for patients who received TH compared to a reference group without TH. There were 1612 patients, of whom 552 (34%) received TH. Median age was 78 (inter-quartile range [IQR] 71-85); 56% was male. 493 (31%) patients survived to hospital discharge, 266 (17%) with CPC of 1 or 2. Of 1292 patients considered for TH, 192 (25%) of 552 patients who received TH survived to hospital discharge and 97 (18%) with good neurologic outcome compared to 150 (20%) and 57 (8%), respectively, without TH. The adjusted odds ratio for survival with good neurologic outcome for TH was 2.0 (95% CI 1.3-3.3). TH is associated with improved neurologic outcome in the elderly population.