title: Immediate defibrillation or defibrillation after cardiopulmonary resuscitation.
abstract: OBJECTIVE
  This study aimed to determine whether short cardiopulmonary resuscitation (CPR) by emergency medical services before defibrillation (CPR first) has a better outcome than immediate defibrillation followed by CPR (shock first) in patients with ventricular fibrillation/pulseless ventricular tachycardia (VF/pulseless VT) out-of-hospital cardiac arrest.
  
  
  METHODS
  We analyzed a national database between 2006 and 2008, and included patients aged 18 years or more who had witnessed cardiac arrests and whose first recorded rhythm was VF/pulseless VT. Those study subjects were divided into five groups in accordance with the CPR/defibrillation intervention sequence. Each group was subdivided into call-to-response intervals of <5 minutes and ≥ 5 minutes. We identified 267 patients in the shock-first group and 6,407 patients in the CPR-first group. One-month survival and neurologically favorable one-month survival rates were used for outcome measures. The association of intervention type on outcomes (one-month survival or neurologically favorable one-month survival) was analyzed using multivariate logistic regression analyses by adjusting potential confounding factors such as survey year, gender, age (years), bystander CPR, intubation, and call-to-response interval (min).
  
  
  RESULTS
  The overall one-month survival rate was 26.2% (3,125/11,941) and the neurologically favorable one-month survival rate was 16.6% (1,983/11,934). The CPR-first group had a one-month survival rate of 27.8% (1,780/6,407) and a neurologically favorable one-month survival rate of 17.8% (1,140/6,404), and the shock-first group had survival rates of 24.7% (66/267) and 18.4% (49/267), respectively. There were no significant differences in one-month survival and neurologically favorable one-month survival in these two primary comparison groups (odds ratio [95% confidence interval], 0.85 [0.64-1.13] and 1.04 [0.76-1.42], respectively). Logistic regression analysis showed that neither CPR first nor shock first was associated with the rate of one-month survival or neurologically favorable one-month survival, after adjusting for potential confounders.
  
  
  CONCLUSIONS
  In our study, CPR prior to attempted defibrillation did not present a better outcome compared with shock first as measured by either one-month survival or neurologically favorable one-month survival, after adjusting for potential confounders. Further studies are required to determine whether CPR first has an advantage over shock first.
authors.affiliation: Department of Planning, Information and Management, the University of Tokyo Hospital, Bunkyo, Japan. koikes@adm.h.u-tokyo.ac.jp
authors.forename: Soichi
authors.initials: S
authors.lastname: Koike
authors.forename: Seizan
authors.initials: S
authors.lastname: Tanabe
authors.forename: Toshio
authors.initials: T
authors.lastname: Ogawa
authors.forename: Manabu
authors.initials: M
authors.lastname: Akahane
authors.forename: Hideo
authors.initials: H
authors.lastname: Yasunaga
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Horiguchi
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Imamura
mesh_terms: D022561:Advanced Cardiac Life Support / Q000295:instrumentation / Q000379:methods*; D000367:Age Factors; D002315:Cardiopulmonary Bypass / Q000379:methods; D016208:Databases, Factual; D004554:Electric Countershock / Q000295:instrumentation / Q000379:methods*; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D058687:Out-of-Hospital Cardiac Arrest / Q000628:therapy*; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States; D014693:Ventricular Fibrillation / Q000401:mortality / Q000628:therapy*