title: Hospital variability of out-of-hospital cardiac arrest survival.
abstract: BACKGROUND
  Previous literature has identified patient and emergency medical services (EMS) system factors that are associated with survival of out-of-hospital cardiac arrest patients.
  
  
  OBJECTIVE
  To determine variability in rates of survival to discharge of resuscitated adult out-of-hospital cardiac arrest patients and to identify hospital-related factors associated with survival.
  
  
  METHODS
  This was a retrospective, observational study of all adult (21 years or older) out-of-hospital Utstein criteria cardiac-etiology arrests treated by Milwaukee County EMS during the period 1995-2005 and surviving to hospital intensive care unit admission. The primary outcome measure was survival to hospital discharge. Logistic regression analysis was used to compare the odds of survival between hospitals, patient factors, and hospital factors.
  
  
  RESULTS
  1,702 patients at eight receiving hospitals were included in the study analyses. Hospital survival rates ranged from 29% to 42%. Patient and case factors associated with increased survival included younger age, male gender, nonwhite race, witnessed arrest in a public location, bystander cardiopulmonary resuscitation (CPR), a modest number of defibrillations, and initial cardiac rhythm of ventricular tachycardia. The only hospital characteristic correlated with survival was the number of beds per nurse. Patients admitted to a hospital with a ratio of beds to nurse less than 1.0 were over 1.5 times more likely to survive.
  
  
  CONCLUSIONS
  Survival to discharge of resuscitated adult out-of-hospital cardiac arrest patients may vary by receiving hospital. A hospital's ratio of beds to nurse and several patient/case f actors are correlated with survival. Further research is warranted to investigate how this may affect resuscitation care, EMS transport policy, and research design.
authors.affiliation: Department of Emergency Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA. jmliu@mcw.edu
authors.forename: J Marc
authors.initials: JM
authors.lastname: Liu
authors.forename: Qing
authors.initials: Q
authors.lastname: Yang
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Pirrallo
authors.forename: John P
authors.initials: JP
authors.lastname: Klein
authors.forename: Tom P
authors.initials: TP
authors.lastname: Aufderheide
mesh_terms: D000328:Adult; D016887:Cardiopulmonary Resuscitation; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006323:Heart Arrest / Q000401:mortality* / Q000628:therapy; D006742:Hospital Bed Capacity; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care; D010561:Personnel Staffing and Scheduling; D012189:Retrospective Studies; D015996:Survival Rate; D014187:Transportation of Patients / Q000458:organization & administration; D014922:Wisconsin / Q000453:epidemiology