title: Survival in out-of-hospital cardiac arrests with initial asystole or pulseless electrical activity and subsequent shockable rhythms.
abstract: BACKGROUND
  Non-shockable arrest rhythms (pulseless electrical activity and asystole) represent an increasing proportion of reported cases of out-of-hospital cardiac arrest (OHCA). The prognostic significance of conversion from non-shockable to shockable rhythms during the course of resuscitation remains unclear.
  
  
  OBJECTIVE
  To evaluate whether out-of-hospital cardiac arrest survival with initially non-shockable arrest rhythms is improved with subsequent conversion to shockable rhythms.
  
  
  METHODS
  Secondary analysis of data in Epistry - Cardiac Arrest, an epidemiologic registry maintained by the Resuscitation Outcomes Consortium (ROC). This analysis includes OHCA events from December 1, 2005 through May 31, 2007 contributed by six US and two Canadian sites. For all EMS-treated adult (18 and older) cardiac arrest patients who presented with non-shockable cardiac arrest, we compared survival to hospital discharge between patients who did develop a shockable rhythm and those who did not based on receipt of subsequent defibrillation. Missing data were handled using multiple imputation. Multivariable logistic regression was used to adjust for potentially confounding variables.
  
  
  RESULTS
  A total of 6556 EMS treated adult cardiac arrest cases presented in non-shockable rhythms. Survival to discharge in patients who converted to a shockable rhythm was 2.77% while survival in those who did not was 2.72% (p=0.92). After adjusting for confounders, conversion to a shockable rhythm was not associated with improved survival (OR 0.88, 95% CI: 0.60-1.30).
  
  
  CONCLUSIONS
  For OHCA patients presenting in PEA/asystole, survival to hospital discharge was not associated with conversion to a shockable rhythm during EMS resuscitation efforts.
authors: Department of Public Health & Preventive Medicine, Oregon Health & Science University, Portland, OR 97239, USA. thomandr@ohsu.edu
authors: Andrew J
authors: AJ
authors: Thomas
authors: Craig D
authors: CD
authors: Newgard
authors: Rongwei
authors: R
authors: Fu
authors: Dana M
authors: DM
authors: Zive
authors: Mohamud R
authors: MR
authors: Daya
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada; D016887:Cardiopulmonary Resuscitation / Q000379:methods* / Q000401:mortality; D015331:Cohort Studies; D004554:Electric Countershock / Q000379:methods / Q000401:mortality*; D004568:Electrodiagnosis / Q000379:methods; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D058687:Out-of-Hospital Cardiac Arrest / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*; D011379:Prognosis; D012042:Registries; D016019:Survival Analysis; D016896:Treatment Outcome; D014481:United States; D055815:Young Adult
keywords: Cardiac arrest; Non-shockable rhythms; Out-of-hospital; Survival