Abstract

Introduction: A fast response to an emergency call is one of the main objectives of an emergency medical communication center (EMCC). For decades, Italy had no formal emergency medical dispatch system to triage and respond to emergency calls. Instead, it used healthcare providers such as nurses to triage and respond to such calls. In 2011, a scripted logic-based dispatch protocol system, the Medical Priority Dispatch System™ (MPDS®), was implemented in the Liguria Region EMCCs in Italy to manage emergency medical calls. However, response delay time (RD) (i.e., time from when the call rings and when emergency medical dispatcher [EMD] picks it up) and duration of emergency call (DEC) (i.e., time from call pick up and to when the case is closed) have not been previously studied in this region. The criticality associated with each distress call is classified into four priority codes: Red (very critical, life-threatening, maximum priority, immediate treatment situations), Yellow (fairly critical, evolving, possible life threatening situations), Green (low critical, not evolving, deferrable situations), and White (non-critical situations, non-urgent patients).

Objective: The primary objective of the study was to evaluate whether or not the use of the MPDS has reduced the RD. The secondary objective was to evaluate the change in the DEC after the implementation of the MPDS.

Methods: The retrospective study analyzed the emergency medical calls that were received by the five Liguria EMCCs, from 2010 to 2015. The data were extracted from a common database maintained by the regional EMCCs. STATA/MP® (version 13) and IBM® SPSS® (Statistics for Windows: version 22.0 ©2013, IBM Corp., Armonk, NY, USA) statistical softwares was used for statistical data analysis, while SigmaPlot software (SigmaPlot: version 12 ©2011, Systat Software, Inc., San Jose California, USA) was used for graphics. The analysis on the response delay (RD) was performed taking into account all the calls received from the EMCCs in the period of interest, i.e. 712,798 calls. The analysis of the calls duration were performed on distress calls (i.e. the calls linked to a potentially critical situation and so excluding all the others calls as requests of information, request for patients' transportation and so on), with a result of 348,187 observations. The outliers, identified through the median absolute deviation method, were excluded from both the study samples. The nonparametric Mann-Whitney U-test was used to assess differences between two independent study groups: WO-MPDS (without MPDS) versus W-MPDS (with MPDS). The significance of the differences were evaluated at 0.05 level of significance. The outcome measures were the response delay to the calls and the duration of the distress calls received from the EMCCs.

Results: Of the 712,520 calls handled by the regional EMCCS, pre-and post-MPDS implementation, 420,530 (59%) were excluded as outliers. After analyzing the remaining 292,468 cases (WO-MPDS: 55,962 calls vs. W-MPDS: 364,568 calls) from all the EMCCs, it was discovered that the median response delay is faster after introducing the MPDS (7,3 sec WO-MPDS vs 6,24 sec W-MPDS). A statistically significant difference was observed between the mean response delay for WO-MPDS and W-MPDS (mean (99%CI): 7.32 (7.30-7.34) and 6.24 (6.23-6.25) seconds, respectively).

Of the 332,673 distress calls handled by the regional EMCCs, 165,404 (49.7%) were excluded as outliers. From the analysis of the remaining 167,269 cases (WO-MPDS: 25,293 calls vs. W-MPDS: 141,976 calls) a sharp increase in the duration of the emergency calls was detected between the WO-MPDS period and W-MPDS period (mean (99%CI): 69.6 (69.4-69.8) and 99.6 (99.5-99.8), respectively). Additionally, the study showed that "red code" calls have a longer mean DEC compared to the "green code" calls (104.6 vs 98.4). That is because with a "red code" call, often the EMD has to provide pre-arrival instructions or needs to stay on line until help arrives.

Conclusion: Implementation of the MPDS significantly reduced the response delay time in Liguria's EMCCs. The duration of the distress calls increased heterogeneously with respect to the priority of dispatch. However, further research should establish other potential benefits of MPDS implementation such as standardization, quality, and quantity of data gathered. Also, the duration measured included provision of PAIs and reflected the total time taken on the call, not the time it took to dispatch a response to the call.