Abstract 181: Relation between Electrocardiographic Changes and Neurologic Outcomes in Patients Treated with Hypothermia after Out-of-hospital Ventricular Fibrillation Cardiac Arrest: J-PULSE-Hypo Registry

Abstract

Background: The 2010 American Heart Association Guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) recommend that comatose adult patients with return of spontaneous circulation (ROSC) after out-of-hospital ventricular fibrillation (VF) cardiac arrest should receive therapeutic hypothermia (Class I). However, it remains unclear whether therapeutic hypothermia is effective for cardiac arrest patients whose have VF initially, but not at hospital arrival. Methods: We conducted a multicenter retrospective study at 14 institutions to evaluate the effect of therapeutic hypothermia on out-of-hospital cardiac arrest between January 2005 and March 2011. The study committee entrusted each hospital with the timing of cooling, cooling methods, target temperature, duration, and rewarming rate. Patients were divided into the VF-VF group, VF-PEA (pulseless electrical activity) group, and VF-Asystole group according to the pre-hospital initial rhythm and the hospital arrival rhythm, and neurologic outcomes at 90 days after cardiac arrest were compared. A favorable outcome was defined as a Cerebral Performance Category (CPC) of 1-2. Results: A total of 135 patients were studied. There were no significant differences among the VF-VF group (n=83), the VF-PEA group (n=35), and the VF-Asystole group (n=17) in age, sex, frequency of witnessed cardiac arrest, the presence of bystander CPR, time to achieving target temperature, or duration of therapeutic hypothermia. The rate of favorable outcomes was higher in the VF-VF group (46%) than in the VF-PEA group (23%; p<0.01) and the VF-Asystole group (6%; p<0.01). Multivariate analysis showed that VF rhythm at hospital arrival was an independent predictor of favorable outcomes at 90 days after cardiac arrest. Conclusions: Our results suggest that therapeutic hypothermia after ROSC most effectively improves neurologic outcomes in patients who have VF initially as well as at hospital arrival, with no ROSC by the time of hospital arrival. Additional therapeutic strategies are needed to improve neurologic outcomes in patients who have VF initially with no ROSC and a rhythm other than VF at hospital arrival.