Background: Emergency Medical Services (EMS) systems often utilize a structured approach to 911 call-taking and emergency medical dispatch (EMD). One such system, Medical Priority Dispatch System (MPDS®), categorizes 911 calls into EMD determinant codes based on problem and severity, with response priorities and resources determined at the local level through a predetermined response matrix.In this study, we proposed a methodology for utilizing historical clinical data to increase the accuracy of 911 call prioritization of patients with time-sensitive critical illness.
Objectives: The primary objective was to increase the number of patients with time-sensitive critical illness who receive the highest-priority response (“Priority 1”). The secondary objective was to decrease the number of Priority 1 responses to patients who do not have time-sensitive critical illness.
Methods: The retrospective, descriptive study included all 911 calls-for-service handled in a large EMS system in North America, between December 1, 2015 and November 30, 2016. Electronic patient care reports (ePCRs) were analyzed for time-sensitive critical illness, including any patients in cardiac or respiratory arrest or who required airway management or electrical therapy (pacing, cardioversion, or defibrillation). The percentage of calls with time-sensitive critical illness was calculated for each of the 382 EMD determinant codes in the MPDS. In the proposed response matrix, any determinant codes which had at least 1% of patients with time-sensitive critical illness were assigned a theoretical Priority 1 response.
Results: Out of a total of 119,287 actual calls-for-service, 30,123 (25.2%) were assigned a Priority 1 response through the current response matrix; 1,205 (4%) of these patients had time-sensitive critical illness. Utilizing our proposed methodology, these same calls-for-service would have resulted in 25,441 (21.3%) Priority 1 responses, including 1,333 (5.2%) patients with time-sensitive critical illness. The net result would have been an overall 15.5% decrease in Priority 1 responses, including a 10.6% increase in patients with time-sensitive critical illness.
Conclusion: Historical clinical data may be used to increase the accuracy of call prioritization of patients with time-sensitive critical illness, while simultaneously increasing operational efficiency and 911 resource utilization.
Keywords: Emergency Medical Dispatch, Medical Priority Dispatch System, Emergency Medical Services Dispatch, Emergency Communications
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