ABSTRACT

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

REFERENCES

1. Medical Priority Dispatch System - IAED. Accessed February 10, 2021. emergencydispatch.org/what-we-do/emergency-priority-dispatch-system/medical-protocol
2. Slovis CM, Carruth TB, Seitz WJ, Thomas CM, Elsea WR. A priority dispatch system for emergency medical services. Annals of Emergency Medicine. 1985;14(11):1055-1060. doi:10.1016/S0196-0644(85)80919-7
3. Hinchey P, Myers B, Zalkin J, Lewis R, Garner D. Low acuity EMS dispatch criteriacan reliably identify patients without high-acuity illness or injury. Prehospital Emergency Care. 2007;11(1):42-48. doi:10.1080/10903120601021366
4. Sporer KA, Johnson NJ. Detailed analysis of prehospital interventions in medical priority dispatch system determinants. The western journal of emergency medicine. 2011;12(1):19-29. Accessed February 10, 2021. ncbi.nlm.nih.gov/pubmed/21691468
5. Dami F, Golay C, Pasquier M, Fuchs V, Carron PN, Hugli O. Prehospital triage accuracy in a criteria based dispatch centre. BMC Emergency Medicine. 2015;15(1):1-9. doi:10.1186/s12873-015-0058-x
6. Heward A, Damiani M, Hartley-Sharpe C. Does the use of the advanced medical priority dispatch system affect cardiac arrest detection? Emergency Medicine Journal. 2004;21(1):115-118. doi:10.1136/emj.2003.006940
7. Flynn J, Archer F, Morgans A. Sensitivity and specificity of the medical priority dispatch system in detecting cardiac arrest emergency calls in melbourne. Prehospital and Disaster Medicine. 2006;21(2):72-76. doi:10.1017/S1049023X00003381
8. Reilly MJ. Accuracy of a Priority Medical Dispatch System in Dispatching Cardiac Emergencies in a Suburban Community Abbreviations: ALS = Advanced Life Support BLS = Basic Life Support CMR = Computerized Medical Records CVA = Cerebrovascular Accident ED = Emergency Department EMD = Emergency Medical Dispatch EMS = Emergency Medical Services MPD = Medical Priority Dispatch. Vol 21.; 2006. doi:10.7916/D8S4730F
9. Bohm K, Kurland L. The accuracy of medical dispatch - a systematic review. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine. 2018;26(1):1-10. doi:10.1186/s13049-018-0528-8
10. Clawson J, Olola CHO, Heward A, Scott G, Patterson B. Accuracy of emergency medical dispatchers’ subjective ability to identify when higher dispatch levels are warranted over a Medical Priority Dispatch System automated protocol’s recommended coding based on paramedic outcome data. Emergency Medicine Journal. 2007;24(8):560-563. doi:10.1136/emj.2007.047928