Conversion to shockable rhythms during resuscitation and survival for out-of hospital cardiac arrest

• Published in: The American journal of emergency medicine 2017-02, Vol.35 (2), p.206-213
• Main Authors: Wah, Win, MBBS, MPH, EMPH, Wai, Khin Lay, MBBS, MSc, Pek, Pin Pin, PgDip (Psych), Ho, Andrew Fu Wah, MBBS, Alsakaf, Omer, MD, Chia, Michael Yih Chong, MBBS, MRCS (Edin), FAMS, Noor, Julina Md, MD, Kajino, Kentaro, MD, PhD, De Souza, Nurun Nisa Amatullah, MBBS, MPH, Ong, Marcus Eng Hock, MBBS, FRCS (Edin) (A&E), MPH
• Format: Article
• Language: English
• Subjects: Age; Aged; Aged, 80 and over; Asia - epidemiology; Cardiac arrest; Cardiopulmonary Resuscitation - statistics & numerical data; Cardiovascular disease; Chi-Square Distribution; Confidence intervals; Emergency; Emergency medical care; Emergency Medical Services - statistics & numerical data; Female; Humans; Logistic Models; Male; Middle Aged; Multivariate analysis; Out-of-Hospital Cardiac Arrest - mortality; Out-of-Hospital Cardiac Arrest - therapy; Outcome Assessment (Health Care) - statistics & numerical data; Prognosis; Registries; Response time; Retrospective Studies; Rhythm; Statistics, Nonparametric; Survival; Survival Analysis
• ISSN: 0735-6757; 1532-8171
• DOI: 10.1016/j.ajem.2016.10.042

Abstract Background In out of hospital cardiac arrest (OHCA), the prognostic influence of conversion to shockable rhythms during resuscitation for initially non-shockable rhythms remains unknown. This study aimed to assess the relationship between initial and subsequent shockable rhythm and post-arrest survival and neurological outcomes after OHCA. Methodology This was a retrospective analysis of all OHCA cases collected from the Pan-Asian Resuscitation Outcomes Study (PAROS) registry in 7 countries in Asia between 2009 and 2012. We included OHCA cases of presumed cardiac etiology, aged 18-years and above and resuscitation attempted by EMS. We performed multivariate logistic regression analyses to assess the relationship between initial and subsequent shockable rhythm and survival and neurological outcomes. 2-stage seemingly unrelated bivariate probit models were developed to jointly model the survival and neurological outcomes. We adjusted for the clustering effects of country variance in all models. Results 40,160 OHCA cases met the inclusion criteria. There were 5356 OHCA cases (13.3%) with initial shockable rhythm and 33,974 (84.7%) with initial non-shockable rhythm. After adjustment of baseline and prehospital characteristics, OHCA with initial shockable rhythm (odds ratio/OR = 6.10, 95% confidence interval/CI = 5.06–7.34) and subsequent conversion to shockable rhythm (OR = 2.00,95%CI = 1.10–3.65) independently predicted better survival-to-hospital-discharge outcomes. Subsequent shockable rhythm conversion significantly improved survival-to-admission, discharge and post-arrest overall and cerebral performance outcomes in the multivariate logistic regression and 2-stage analyses. Conclusion Initial shockable rhythm was the strongest predictor for survival. However, conversion to subsequent shockable rhythm significantly improved post-arrest survival and neurological outcomes. This study suggests the importance of early resuscitation efforts even for initially non-shockable rhythms which has prognostic implications and selection of subsequent post-resuscitation therapy.