Evaluating emergency medical service performance measures

Abstract

The ultimate goal of emergency medical service systems is to save lives. However, most emergency medical service systems have performance measures for responding to 911 calls within a fixed timeframe (i.e., a response time threshold), rather than measures related to patient outcomes. These response time thresholds are used because they are easy to obtain and to understand. This paper proposes a methodology for evaluating the performance of response time thresholds in terms of resulting patient survival rates. A model that locates ambulances to optimize patient survival rates is used for base comparison. Results are illustrated using real-world data collected from Hanover County, Virginia. The results indicate that locating ambulances to maximize seven and eight min response time thresholds simultaneously maximize patient survival. Nine and 10 min response time thresholds result in more equitable patient outcomes, with improved patient survival rates in rural regions.

A simulation model to enable the optimization of ambulance fleet allocation and base station location for increased patient survival

“…It was found that the existing covering models produced sub-optimal EMS facility distributions when evaluated using the more realistic performance measure. Indeed, in recognizing the importance of performance measures being more closely related to patient outcomes, McLay and Mayorga [38,39] investigated the inuence of maximizing coverage for dierent response time thresholds on patient survival rates. Acknowledging that the ndings were specic to the rural/urban geographic region considered, locating ambulances to maximize minumum response time thresholds was found to simultaneously maximized patient survival.…”

Hypercube Queuing Models in Emergency Service Systems: A State-of-the-Art Review

“…They also proposed a model to estimate travel time distribution between each pair of server and customer in a case study. McLay and Mayorga [31] proposed a location model to maximize two performance measures: 1) the expected number of customers who are survived and 2) the expected number of customers who are responded to within the specified time threshold. These two performance measures are functions of response time, which is affected by the distance between servers and customers.…”

A generic method to develop simulation models for ambulance systems

“…The response time is widely used because this performance measure is usually associated with patient survival [53,54,55,56,57,58].…”