Prehospital Detection of Acute Pulmonary Embolism and Its Association with Clinical Outcomes: A Retrospective Cohort Study

Background: Pulmonary embolism (PE) is a potentially life-threatening condition requiring timely diagnosis and treatment. However, data on prehospital correct PE detection by emergency medical services (EMS) are scarce. Methods: We conducted a retrospective single-center cohort study at the BG University Hospital Bergmannsheil Bochum, Germany, including all patients with in-hospital confirmed PE (ICD-10: I26.0/I26.9) and admitted by EMS between January 2019 and December 2024. Prehospital PE detection was defined as documentation of PE as the working diagnosis in the EMS protocol. Time to definitive diagnosis was calculated from EMS alarm to computed tomography pulmonary angiography (CTPA) acquisition. Multivariable Cox regression and logistic and linear regression models were used to identify predictors of time to diagnosis and clinical outcomes. Main Results: Of 171 patients included, prehospital PE was correctly suspected in only nine cases (5.3%, 95% CI 2.8–9.7%). Time to definitive diagnosis was significantly shorter in patients with correct prehospital PE recognition than in those without (median 2.1 vs. 4.0 h, log-rank p < 0.001). In an exploratory analysis, detection occurred only in physician-staffed EMS encounters (10.8% vs. 0%, p = 0.003). Prehospital intravenous heparin, administered predominantly for suspected myocardial infarction, was also associated with a higher rate of CTPA acquisition, 2.42 (95% CI 1.40–4.19), likely reflecting confounding by indication. Overall, 56 patients (33.1%) were not diagnosed within 6 h of emergency department presentation; 38 (22.5%) were diagnosed only after more than 24 h. Conclusions: Correct detection of PE by EMS is critically low, yet correct detection is associated with earlier imaging. These findings highlight the urgent need for EMS-specific diagnostic strategies and prospective trials to improve prehospital PE detection.