title: Collapse-to-emergency medical service cardiopulmonary resuscitation interval and outcomes of out-of-hospital cardiopulmonary arrest: a nationwide observational study.
abstract: BACKGROUND
  The relationship between collapse to emergency medical service (EMS) cardiopulmonary resuscitation (CPR) interval and outcome has been well documented. However, most studies have only analyzed cases of cardiac origin and Vf (ventricular fibrillation)/pulseless VT (ventricular tachycardia). We sought to examine all causes of cardiac arrest and analyze the relationship between collapse-to-EMS CPR interval and outcome in a nationwide sample using an out-of-hospital cardiac arrest (OHCA) registry.
  
  
  METHODS
  This was a retrospective observational study based on a nationwide OHCA patient registry in Japan between 2005 and 2008 (n = 431,968). We included cases where collapse was witnessed by a bystander and where collapse and intervention time were recorded (n = 109,350). Data were collected based on the Utstein template. One-month survival and neurologically favorable one-month survival were used as outcome measures. Logarithmic regression and logistic regression were used to examine the relation between outcomes and collapse-to-EMS CPR interval.
  
  
  RESULTS
  Among collapse-to-EMS CPR intervals between 3 and 30 minutes, the logarithmic regression equation for the relationship with one-month survival was y = -0.059 ln(x) + 0.21, while that for the relationship with neurologically favorable one-month survival was y = -0.041 ln(x) + 0.13. After adjusting for potential confounders in the logistic regression analysis for all intervals, longer collapse-to-EMS CPR intervals were associated with lower rates of one-month survival (odds ratio (OR) 0.93, 95% confidence interval (CI): 0.93 to 0.93) and neurologically favorable one-month survival (OR 0.89, 95% CI 0.89 to 0.90).
  
  
  CONCLUSIONS
  Improving the emergency medical system and CPR in cases of OHCA is important for improving the outcomes of OHCA.
authors.affiliation: Department of Planning, Information and Management, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan. koikes@adm.h.u-tokyo.ac.jp
authors.forename: Soichi
authors.initials: S
authors.lastname: Koike
authors.forename: Toshio
authors.initials: T
authors.lastname: Ogawa
authors.forename: Senzan
authors.initials: S
authors.lastname: Tanabe
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsumoto
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: Tomoaki
authors.initials: T
authors.lastname: Imamura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016887:Cardiopulmonary Resuscitation; D004632:Emergency Medical Services; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000628:therapy*; D012042:Registries; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome