CORS / Optimization Days 

HEC Montréal, May 29-31, 2023


HEC Montreal, 29 — 31 May 2023

Schedule Authors My Schedule

ECM Emergency Care Management

May 31, 2023 10:30 AM – 12:10 PM

Location: Serge-Saucier (blue)

Chaired by Valérie Bélanger

3 Presentations

  • 10:30 AM - 10:55 AM

    The Cost of Task Switching: Evidence from Emergency Departments

    • Yiwen Jin, presenter, UBC Sauder School of Business
    • Yige Duan, UBC Vancouver School of Economics
    • Yichuan Ding, McGill University
    • Mahesh Nagarajan, UBC Sauder School of Business
    • Garth Hunte, UBC Department of Emergency Medicine

    Emergency department (ED) physicians treat patients with different symptoms and constantly switch between tasks. Using three years' data on patient visits and lab tests from two EDs, we investigate the impact of task switching on physician productivity, quality of care, and patient routing. We then provide operational solutions after identification. To address estimation bias due to measurement errors and endogenous patient selection, we refine the sample period and construct an instrumental variable called switching likelihood that exploits the exogenous composition of waiting patients. Our estimates indicate that, at different EDs, a 10% increase in the switching frequency of physicians reduces the number of patients treated per hour by 8.7% - 11.5% on average. However, we find that it has no significant influence on treatment quality. By exploring the heterogeneous impact on physician productivity among different patient pairs from data, we leverage a max bisection algorithm to partition patients into two clusters to minimize the negative impact of task switching. We propose a data-driven queue management method to partition patients into two queues. Based on the simulation of implementing the proposed two-queue system in our collaborating EDs, we find that the average waiting time is reduced by about 40%.

  • 10:55 AM - 11:20 AM

    A Comparative Analysis of Prioritization Systems for Pre-Hospital Emergency Services in Quebec

    • Vittorio Nicoletta, presenter, Laval University
    • Valérie Bélanger, CIRRELT, HEC Montréal
    • Maxime Robitaille-Fortin, Coopérative des techniciens ambulanciers du Québec
    • Jessica Harrison, Université de Sherbrooke

    Emergency Medical Services (EMS) dispatchers use prioritization systems to determine the nature and urgency of an emergency call, and to dispatch pre-hospital emergency services accordingly. However, different prioritization systems can vary in their ability to accurately predict call priorities, potentially leading to under- or over-triage situations that negatively impact both patient outcomes and healthcare costs.
    To address this issue, we conducted a comparative analysis of two prioritization systems used in Quebec: the widely adopted Medical Priority Dispatch System (MPDS), and an ad-hoc provincial system. Using data from pre-hospital emergency services operating in the province, we evaluated the performance of these systems across various emergency scenarios.
    Our analysis revealed a tendency for both the MPDS and provincial systems to over-triage, i.e., to prioritize calls as urgent to avoid missing potentially critical situations. We also identified specific MPDS codes and provincial system levels that exhibited a high frequency of over-prioritization. Ultimately, the choice of prioritization system should be based on the specific objectives and desired performance of the healthcare system.
    Overall, our study provides valuable insights into the strengths and limitations of different prioritization systems for pre-hospital emergency services, and identifies potential directions for future research and improvement.

  • 11:20 AM - 11:45 AM

    A simulation study of the operational effects of expanding secondary triage of calls for medical emergencies

    • Luc de Montigny, Urgences-santé
    • Gabriel Lavoie, Urgences-santé
    • Aman Verma, McGill University
    • Valérie Bélanger, presenter, HEC Montréal
    • Nadia Lahrichi, Polytechnique Montréal

    EMS systems are challenged by chronic staffing shortages, steadily growing call volumes, especially for non-urgent care, and the concomitant role as a gateway to primary healthcare. In response, many systems are introducing or expanding secondary triage to manage demand without abandoning patients. The safety of secondary triage is moderately well documented. However, there has been little study of its effects on operational efficiency. In this project, we use a discrete-event simulator, based on 2019 procedures and data from a large urban EMS system in Canada, to analyze scenarios that consider secondary triage alone and in combination with enhancement to primary triage. Key performance indicators include response time (RT), lights-and-siren travel (LST), ambulance reassignments (AR) and system utilization rates (UR). Our results suggest that combining enhanced secondary and primary triage could improve RT for all priorities, while producing important reductions in LST and AR, and non-trivial improvements to UR.