Incidence and outcomes of emergency medical service treated pulmonary embolism in Victoria, Australia: A...

Pulmonary embolism (PE) is a major cause of cardiovascular morbidity and mortality. However, population-level data describing the prehospital presentation and outcomes of emergency medical service (EMS)-treated patients remain limited. We aimed to determine the incidence, clinical characteristics, and outcomes of patients with EMS-treated PE in Victoria, Australia.

This population-based cohort study included adults attended by a single statewide EMS provider between January 1, 2015, and November 28, 2020, with an in-hospital primary diagnosis of PE. Prehospital electronic patient care records were linked with statewide hospital and death registry datasets. The primary outcome was 30-day all-cause mortality. Multivariable analyses were performed to assess predictors of 30-day mortality.

Among 3,976,574 EMS-attended patients (29.6 million person-years), 6,769 had a confirmed PE, yielding an incidence of 22.9 per 100,000 person-years (95% CI, 22.3-23.4), which increased over the study period from 22.86 in 2015-22.84 per 100,000 person years in 2020 (P_trend = 0.04). The mean (SD) age was 64.7 (17.3) years. The 30-day mortality was 7.0%, ranging from 0.5% in very low-risk to 19.3% in very high-risk Pulmonary Embolism Severity Index (PESI) categories (P < 0.001). Independent predictors of 30-day mortality included older age, pre-hospital cardiac arrest, pre-existing malignancy, diabetes, and altered vital signs (low systolic blood pressure, hypoxia, and tachypnea). Only 4.2% of patients were discharged directly from the emergency department.

PE treated by EMS is increasingly common and carries a substantial short-term mortality risk. These findings suggest that established risk stratification tools may help optimize prehospital triage and improve systems of care, however, further dedicated studies are required.