title: Resistance to conventional cardiopulmonary resuscitation in witnessed out-of-hospital cardiac arrest patients with shockable initial cardiac rhythm.
abstract: Shockable initial cardiac rhythm is a key predictor of survival after out-of-hospital cardiac arrest (OHCA). However, not all patients with shockable OHCA achieve return of spontaneous circulation (ROSC) via conventional cardiopulmonary resuscitation (CPR). Therefore, we retrospectively analyzed patients with witnessed OHCA and shockable initial cardiac rhythm to identify the resistance factors for conventional CPR.
  
  
  
  We retrospectively analyzed consecutive patients with witnessed OHCA and shockable initial cardiac rhythm who were admitted to our hospital between October 2009 and October 2014. We then compared the baseline characteristics, pre-hospital clinical course, and causes of the cardiopulmonary arrest among patients who achieved ROSC via conventional CPR and patients who did not achieve ROSC via conventional CPR and underwent extracorporeal CPR (ECPR).
  
  
  
  A total of 85 patients achieved ROSC via conventional CPR (non-ECPR group) and 40 patients did not achieve ROSC via conventional CPR and underwent ECPR (ECPR group). Among these 125 patients, 113 had known causes for their cardiopulmonary arrest, including 66 cases (53%) of acute myocardial infarction (AMI). There were no significant differences in the causes of arrest between the non-ECPR and ECPR cases. However, among the 66 cases of AMI (43 non-ECPR and 23 ECPR), the rate of non-recanalization during the initial coronary angiography was significantly higher among the ECPR cases (non-ECPR: 58% vs. ECPR: 87%; p=0.03).
  
  
  
  The major cause of witnessed OHCA with shockable initial cardiac rhythm was AMI, and resistance to conventional CPR was related to continuous myocardial ischemia.
authors.affiliation: Senri Critical Care Medical Center, Osaka Saiseikai Senri Hospital, Osaka, Japan. Electronic address: sonnyboy@tempo.ocn.ne.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Otani
authors.affiliation: Senri Critical Care Medical Center, Osaka Saiseikai Senri Hospital, Osaka, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Sawano
authors.affiliation: Senri Critical Care Medical Center, Osaka Saiseikai Senri Hospital, Osaka, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Oyama
authors.affiliation: Senri Critical Care Medical Center, Osaka Saiseikai Senri Hospital, Osaka, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Morita
authors.affiliation: Senri Critical Care Medical Center, Osaka Saiseikai Senri Hospital, Osaka, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Natsukawa
authors.affiliation: Senri Critical Care Medical Center, Osaka Saiseikai Senri Hospital, Osaka, Japan.
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Kai
mesh_terms: D000368:Aged; D016887:Cardiopulmonary Resuscitation / Q000009:adverse effects* / Q000379:methods; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000150:complications / Q000628:therapy; D004554:Electric Countershock / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000628:therapy; D017202:Myocardial Ischemia / Q000150:complications* / Q000628:therapy; D058687:Out-of-Hospital Cardiac Arrest / Q000209:etiology / Q000628:therapy*; D012189:Retrospective Studies; D017211:Treatment Failure
keywords: Acute myocardial infarction; Extracorporeal cardiopulmonary resuscitation; Out-of-hospital cardiac arrest