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%). CONCLUSION: 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.
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%). CONCLUSION: 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.