TL;DR: This paper forms a model for determining how to optimally dispatch distinguishable servers to prioritized customers given a set of equity constraints and draws upon the decision analytic and social science literature to compare the effects of different notions of equity on the resulting dispatching policies.
Abstract: The decision about which servers to dispatch to which customers is an important aspect of service systems. This decision is complicated when servers must be equitably---as well as efficiently---dispatched to customers. In this paper, we formulate a model for determining how to optimally dispatch distinguishable servers to prioritized customers given a set of equity constraints. These issues are examined through the lens of emergency medical service EMS dispatch, for which a Markov decision process model is developed that captures how to dispatch ambulances servers to prioritized patients customers. It is assumed that customers arrive sequentially, with the priority and location of each customer becoming known upon arrival. Four types of equity constraints are considered---two of which reflect customer equity and two of which reflect server equity---all of which draw upon the decision analytic and social science literature to compare the effects of different notions of equity on the resulting dispatching policies. The Markov decision processes are formulated as equity-constrained linear programming models. A computational example is applied to an EMS system to compare the different equity models.
TL;DR: In this article, the authors examined the interrelated effects of the unprecedented global increase of EMS call, the effect of the COVID-19 crisis on responding to non-COVID19 emergencies, and the concurrent effects of having overwhelmed dispatch centers.
Abstract: Background Over the course of the COVID-19 progress, reports from many locations around the world indicated major increases in EMS call volume, which imposed great pressure on EMS dispatch centers (EMSDC) globally. No studies yet have been done to examine this phenomenon. Objective This paper examines the interrelated effects of the unprecedented global increase of EMS call, the effect of the COVID-19 crisis on responding to non-COVID-19 emergencies, and the concurrent effects of having overwhelmed dispatch centers. It tries to explain the current evidence of the bottleneck of EMS calls during the early phase of the worldwide pandemic. Eligibility criteria We examine the numbers of EMS calls internationally between March and June 2020, derived from published literature and news media. Only articles in English were selected, with certain keywords related to EMS calls, ambulance delay, stroke and cardiac arrest. Source of evidence Google Scholar was the main searching source. Results After applying the selection criteria, a total of 29 citations were chosen, and a pattern of knowledge resulted in the emergence of five themes: EMS calls during COVID-19, Reduced EMS operator response time, Ambulance response delays, Collateral mortality and morbidity among non-COVID-19 cases, and Total ambulance call time. Conclusion Over the course of COVID-19 progress, there was a global phenomenon of exponential increases in EMS calls, which is expected to impose a great pressure on EMS dispatch centers. Several factors contributing to the bottleneck of EMS calls are identified and explained.
TL;DR: The proportion of crashes that required a response by emergency medical services (EMSs), the timeliness of the response, the proportion of patients treated in local hospitals, and the factors that predicted referral to trauma centers were determined.
Abstract: OBJECTIVE: To determine the current role of rural hospitals and prehospital agencies in the care of motor vehicle crash victims in a remote, rural county prior to the statewide regionalization of trauma care. Specifically, we determined the proportion of crashes that required a response by emergency medical services (EMSs), the timeliness of the response, the proportion of patients treated in local hospitals, and the factors that predicted referral to trauma centers. DESIGN: Population-based retrospective cohort study linking emergency medical services, emergency department, and hospital discharge data to police motor vehicle crash reports and coroner data. SETTING: Okanogan County, Washington. SUBJECTS: All motor vehicle occupants, pedestrians or pedalcyclists who were involved in a motor vehicle collision with a response by emergency medical system personnel or the county coroner. INTERVENTION: None. MAIN OUTCOME MEASURES: EMS response times, emergency department and hospital discharge disposition, Injury Severity Scores, hospital length of stay, procedures, deaths. RESULTS: Twelve percent of 669 crashes reported to the police led to the dispatch of EMS. Crashes with EMS involvement were more likely to include occupants without restraints, who were ejected from the vehicle or who had alcohol as a contributing circumstance. The median interval between crash and EMS dispatch was 5 minutes (95th percentile: 40 minutes), the median scene time was 15 minutes (95th percentile: 35 minutes), and the median interval between dispatch and emergency department arrival was 48 minutes (95th percentile: 95 minutes). Among the 210 patients treated by EMSs, 67 (32%) were admitted to local hospitals, and 19 (9%) were referred to a distant trauma center. Of these, 17 were referred directly from the emergency department, one from the scene, and one after local admission. Compared with patients who were admitted locally, referred patients had a significantly higher mean Injury Severity Score (14.4 vs. 5.1), hospital length of stay (9.1 vs. 1.8 days), and rate of operative procedures (37% vs. 9%). Of the 13 crash-related deaths during the year, nine were declared dead at the scene before EMS arrival, three were asystolic at the time of EMS arrival at the scene, and one died at a referral hospital. CONCLUSIONS: The linkage of data from police, prehospital agencies, and hospitals can reveal important information about the sequence of health care for trauma patients. The rural hospitals in this county currently play a major role in the stabilization and treatment of motor vehicle crash victims. Language: en
TL;DR: This study compared dispatch priority decisions with apparent patient need, based on emergency department (ED) presentation, by matching 320 ED charts with corresponding EMS dispatch and run information.
Abstract: Inappropriate use of emergency medical services (EMS) for nonemergencies strains EMS resources and limits efficiency. Protocol-driven dispatch systems attempt to correct the imbalance that exists between demand and available resources by prioritizing 911 calls. This study compared dispatch priority decisions with apparent patient need, based on emergency department (ED) presentation, by matching 320 ED charts with corresponding EMS dispatch and run information. The priorities assigned by the system based on dispatch information were compared with those assigned by a three-member panel of physicians based on ED presentation. The physicians and dispatchers agreed on the need for advanced life support (ALS) versus basic life support (BLS) transport 74% of the time. There was only 43% agreement on the more detailed 4-level classification system. The system assigned the highest level of dispatch utilizing combined ALS and first responders to a significantly greater degree than did the physicians. It was concluded that protocol systems for setting dispatch priorities utilize EMS resources to a higher degree than actually required based on ED presentation.
TL;DR: Dual dispatch of fire-fighters and EMS in OHCA significantly reduced response times in all studied regions, and the 30-day survival increased significantly in the downtown and suburban populations, while a limited impact was seen in the rural areas.