The Clinical History of Patients Entering the Healthcare System through Medical 9-1-1 Calls

de Montigny, L; Verma, A; Hao, S; Williamson, T; Lang, ES; Doig, CJ; Blanchard, IE

Introduction: Due to the difficulty of linking patient-level data across prehospital and hospital care, we have a limited knowledge of the trajectory of patients seeking care through 9-1-1. This knowledge gap inhibits an understanding of the relationship between call-taking, paramedic interventions, and post-transport outcomes, which is critical for system planning.

Objective: To describe the trajectory of patients from 9-1-1 call-taking to outcomes.

Methods: Descriptive analyses of calls to 9-1-1 from two large urban EMS systems (Quebec [QC] and Alberta [AB]) that use the Medical Priority Dispatch System (MPDS) for call-taking triage. The study cohort included all 9-1-1 calls for adult patients from 2018 to 2021 with sufficient information to link to outcome. The dataset included patient acuity on scene (Critical Illness Prediction score [CIP]; time-dependent paramedic intervention), and post-transport outcomes (ICU admission; all-cause mortality at discharge).

Results: A total of 611 125 calls were included (QC=323 198; AB=287 927). QC reported 28.7% as high priority (Delta/Echo) and 71.2% as low priority (Alpha/Bravo/Charlie); AB reported 31.0% and 69.0% respectively. High risk of critical illness (CIP=4–8) was 2.0% (QC) and 1.0% (AB), 1.4% (QC) and 5.6% (AB) received at least one time-dependent paramedic intervention, ICU admission was 1.2% (QC) and 2.9% (AB), and all-cause mortality was 3.8% (QC) and 4.4% (AB). The most common patient trajectory was the low-priority call for a patient with low-risk of critical illness who received no time-dependent paramedic interventions, was not admitted to the hospital, and did not die (QC=48.3% and AB=30.0%). High-priority calls for a patient with high-risk of critical illness who received a time-dependent paramedic intervention and was admitted to the ICU were rare (high priority: QC=0.03% and AB=0.06%).

Conclusion: The most common trajectory was a clinically stable patient not requiring emergent prehospital or ICU care. These results support initiatives to preserve emergency resources for critically ill patients and orient others to alternative care.