Abstract 290: Association Between Hourly Call Volume in Emergency Medical Dispatch Center and Dispatcher -Assisted Cardiopulmonary Resuscitation Instruction Time in Out-Of-Hospital Cardiac Arrest

Abstract

Objectives: cardiac arrest recognition, ambulance dispatch and dispatcher assisted CPR by emergency medical dispatch (EMD) is crucial for good outcome of out-of-hospital cardiac arrest (OHCA).In EMD, crowding is caused by mismatch between numerous emergency calls and dispatchers per duty available Crowding in emergency department has been shown to decrease the performance and outcome, however little is known about effect of crowding in EMD. We aimed to evaluate incidence of crowding in emergency medical dispatch center and effect of emergency call crowding on dispatcher assisted CPR instruction performance in OHCA calls. Methods: We used nationwide OHCA database from 2013 to 2016, consisted of patients with presumed cardiac origin and dispatched by Seoul EMD. Main exposure was hourly number of total incoming emergency calls to EMD. Number of hourly calls were categorized into quartile (~4o calls, 41~51 calls, 52 ~61 calls and ~62 calls). Primary outcome was successful DA-CPR instruction provision within 120 seconds. Adjusted ratios (AORs) and 95% confidence intervals (CIs) were estimated to evaluate association between EMD crowding and outcome in multivariable logistic regression model. Results: Of a total of 12,722 patients, proportion of successful DA instruction were highest in least crowded quartile and lowest in the most crowded quartile (22.7% vs. 15.o% , p<0.01). The adjusted odds ratios is 0.85 (95% CI 0.74 - 0.98) in most crowded EMD quartile with lesser proportion of DA instruction within 120 seconds. Crowding quartile 4 and quartile 3 was associated lesser favorable neurological outcome in multivariable logistic regression model.(adjusted OR(95% CI) 0.78 (0.60-0.99) and 0.70 (0.54- 0.91) respectively) . Conclusion: Crowding in emergency medicine dispatch caused by increased hourly call volume was associated with delayed dispatcher assisted CPR instruction provision. Medical directors might consider strategy approach to solve crowding in EMD according to crowding distribution.