title: Delay prior to calling 9-1-1 is associated with increased mortality after out-of-hospital cardiac arrest.
abstract: OBJECTIVE
  We sought to characterize the collapse-to-9-1-1 call interval, to evaluate the frequency of pre-9-1-1 delay, and to assess whether delay is associated with decreased survival after out-of-hospital cardiac arrest (OHCA).
  
  
  METHODS
  This was a five-year prospective survey of bystanders to adult OHCA cases in which the victims were transported to seven local teaching hospitals in Michigan. Bystander data were obtained by telephone interview beginning two weeks after the event, and through review of emergency medical services (EMS) documents. Criteria for pre-9-1-1 delay were prospectively developed. Two paramedic reviewers were trained on these criteria and reviewed bystander and EMS data for each cardiac arrest case. Multivariate regression analysis was used to assess the independent impact of delay on survival. We collected common bystander and EMS OHCA demographics, as well as bystander description of events prior to the 9-1-1 call. Outcome was survival to hospital discharge.
  
  
  RESULTS
  During the study period we identified 1,004 OHCAs, for which 779 bystanders completed interviews. Of these interviews, 688 had adequate data for analysis. Raters showed moderate to strong agreement for a 15% subsample of cases. Of all cases, 330 (48%) were identified as having had pre-9-1-1 delay. Delay was less commonly associated with witnessed arrest (odds ratio [OR] 2.7; 95% confidence interval [CI] 2.0-3.7%) and public location (OR 1.57; 95% CI 1.1-2.2%). In a multivariate model, only initial-rhythm ventricular tachycardia/ventricular fibrillation was associated with improved survival (OR 2.28; 95% CI 1.3-4.1), and pre-9-1-1 delay was associated with decreased survival (OR 0.46; 95% CI 0.3-0.9%).
  
  
  CONCLUSIONS
  This method demonstrated that prehospital delay is common in OHCA and is associated with increased mortality. Measurement of pre-9-1-1 delay may improve precision of predictive models for OHCA survival.
authors.affiliation: Department of Emergency Medicine, William Beaumont Hospital, Royal Oak, Michigan 48073, USA. raswor@beaumont.edu
authors.forename: Robert A
authors.initials: RA
authors.lastname: Swor
authors.forename: Scott
authors.initials: S
authors.lastname: Compton
authors.forename: Robert
authors.initials: R
authors.lastname: Domeier
authors.forename: Nika
authors.initials: N
authors.lastname: Harmon
authors.forename: Kevin
authors.initials: K
authors.lastname: Chu
mesh_terms: D000328:Adult; D000368:Aged; D004631:Emergency Medical Service Communication Systems / Q000706:statistics & numerical data; D005260:Female; D006323:Heart Arrest / Q000401:mortality* / Q000628:therapy*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008824:Michigan / Q000453:epidemiology; D015999:Multivariate Analysis; D011446:Prospective Studies; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome