title: Advanced rescuer- versus citizen-witnessed cardiac arrest: Is there a difference in outcome?
abstract: BACKGROUND
  Substantial financial and human resources are invested in training and maintaining advanced life support (ALS) skills of paramedics who are deployed to the field in response to out-of-hospital cardiac arrest. It would be expected that patients who experience cardiac arrest in the presence of a trained health care practitioner, such as a paramedic, have better outcomes.
  
  
  OBJECTIVE
  To compare the rates of return of spontaneous circulation (ROSC), survival to hospital admission (SHA), and survival to hospital discharge (SHD) between paramedic-witnessed out-of-hospital cardiac arrest vs. citizen-witnessed out-of-hospital cardiac arrest.
  
  
  METHODS
  In this retrospective cohort study, the records of all out-of-hospital nontraumatic cardiac arrest patients presenting to a municipal teaching hospital from November 1, 1994, through June 30, 2008, were reviewed. The age, gender, race, rhythm on paramedic arrival, presence of bystander cardiopulmonary resuscitation (CPR), whether it was a witnessed arrest and, if witnessed, whether it was a paramedic-witnessed arrest, site of the arrest, and the rate of SHD were noted. A univariate odds ratio was computed to describe the association between paramedic-witnessed out-of-hospital cardiac arrest vs.citizen-witnessed out-of-hospital cardiac arrest and SHD. A multivariable logistic regression analysis was also performed, controlling for age, gender, arrest rhythm, bystander CPR, and site of arrest.
  
  
  RESULTS
  Of the total cohort of 1,294 out-of-hospital cardiac arrests, 750 (52.6%) were either paramedic-witnessed (154/750 = 20.5%) or citizen-witnessed (596/750 = 79.5%). Among the witnessed cardiac arrests, overall the SHD was 53 of 750 (7.1%). On univariate analysis, the ROSC, SHA, or SHD rates were not statistically significantly different between paramedic- and citizen-witnessed arrests. Even after multivariable adjustment, the ROSC, SHA, and SHD rates were not significantly different between paramedic- and citizen-witnessed arrests.
  
  
  CONCLUSIONS
  Among our study population of out-of-hospital cardiac arrest victims, paramedic-witnessed arrests did not appear to have improved survival rates when compared with citizen-witnessed arrests.
authors.affiliation: Department of Emergency Medicine, Harbor-UCLA Medical Center, Torrance, California, USA.
authors.forename: Amy H
authors.initials: AH
authors.lastname: Kaji
authors.forename: Arslan M
authors.initials: AM
authors.lastname: Hanif
authors.forename: James T
authors.initials: JT
authors.lastname: Niemann
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016887:Cardiopulmonary Resuscitation / Q000706:statistics & numerical data*; D016001:Confidence Intervals; D004632:Emergency Medical Services; D004634:Emergency Medical Technicians / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D058687:Out-of-Hospital Cardiac Arrest / Q000401:mortality / Q000628:therapy*; D012189:Retrospective Studies; D013223:Statistics as Topic; D016896:Treatment Outcome