title: A model of survival following pre-hospital cardiac arrest based on the Victorian Ambulance Cardiac Arrest Register.
abstract: OBJECTIVE
  This study describes the epidemiology of sudden cardiac arrest patients in Victoria, Australia, as captured via the Victorian Ambulance Cardiac Arrest Register (VACAR). We used the VACAR data to construct a new model of out-of-hospital cardiac arrest (OHCA), which was specified in accordance with observed trends.
  
  
  METHODS
  All cases of cardiac arrest in Victoria that were attended by Victorian ambulance services during the period of 2002-2005.
  
  
  RESULTS
  Overall survival to hospital discharge was 3.8% among 18,827 cases of OHCA. Survival was 15.7% among 1726 bystander witnessed, adult cardiac arrests of presumed cardiac aetiology, presenting in ventricular fibrillation or ventricular tachycardia (VF/VT), where resuscitation was attempted. In multivariate logistic regression analysis, bystander CPR, cardiac arrest (CA) location, response time, age and sex were predictors of VF/VT, which, in turn, was a strong predictor of survival. The same factors that affected VF/VT made an additional contribution to survival. However, for bystander CPR, CA location and response time this additional contribution was limited to VF/VT patients only. There was no detectable association between survival and age younger than 60 years or response time over 15min.
  
  
  CONCLUSIONS
  The new model accounts for relationships among predictors of survival. These relationships indicate that interventions such as reduced response times and bystander CPR act in multiple ways to improve survival.
authors.affiliation: Strategic Planning Department, Metropolitan Ambulance Service, 375 Manningham Road, Doncaster 3108, Victoria, Australia. Masha.Fridman@mas.vic.gov.au
authors.forename: Masha
authors.initials: M
authors.lastname: Fridman
authors.forename: Vanessa
authors.initials: V
authors.lastname: Barnes
authors.forename: Andrew
authors.initials: A
authors.lastname: Whyman
authors.forename: Alex
authors.initials: A
authors.lastname: Currell
authors.forename: Stephen
authors.initials: S
authors.lastname: Bernard
authors.forename: Tony
authors.initials: T
authors.lastname: Walker
authors.forename: Karen L
authors.initials: KL
authors.lastname: Smith
mesh_terms: D000552:Ambulances / Q000706:statistics & numerical data*; D016887:Cardiopulmonary Resuscitation / Q000379:methods* / Q000706:statistics & numerical data; D004632:Emergency Medical Services / Q000706:statistics & numerical data*; D005260:Female; D006323:Heart Arrest / Q000401:mortality* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D017063:Outcome Assessment, Health Care / Q000379:methods*; D012042:Registries / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D016019:Survival Analysis; D015996:Survival Rate / Q000639:trends; D014739:Victoria / Q000453:epidemiology