Association of initial rhythm with neurologically favorable survival in non-shockable out-of-hospital cardiac arrest without a bystander witness or bystander cardiopulmonary resuscitation

Background: Out-of-hospital cardiac arrest (OHCA) has a predominantly non-shockable rhythm. Non-shockable rhythm, and the absence of a bystander witness or bystander cardiopulmonary resuscitation (CPR) are associated with poor outcomes. However, the association between the type of non-shockable rhythm and outcomes is not well known. Objective: To examine the association between the initial rhythm and neurologically favorable outcomes after non-shockable OHCA without a bystander witness or bystander CPR. Methods: In a nationwide, population-based, cohort study, we analyzed 213,984 adult OHCA patients with a non-shockable rhythm who had neither a bystander witness nor bystander CPR. They were identified through the Japanese national OHCA registry data from January 1, 2005 to December 31, 2010. The primary outcome was neurologically favorable survival. Results: Among 213,984 patients, the initial rhythm was Pulseless Electrical Activity (PEA) in 31,179 patients (14.6%) and Asystole in 182,805 patients (85.4%). The neurological outcome was more favorable in PEA than in Asystole (1.4% vs. 0.2%, p < 0.0001). After adjusting for age, sex, etiology of arrest, epinephrine administration, advanced airway management, time from call to contact with patient, and calendar year, PEA was associated with an increased neurologically favorable survival rate (odds ratio 7.86; 95% confidence interval 6.81-9.07). In subgroup analysis stratified by age group (18-64, 65-84, or >= 85 years), the neurologically favorable survival rate was >= 1% in PEA, even for patients aged >= 85 years, but <1% in Asystole among all age groups. Conclusion: PEA and Asystole should not be considered to be identical to non-shockable rhythm, but rather should be clearly distinguished from each other from the perspective of quantitative medical futility. (C) 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.