Identification of prearrest clinical factors associated with outpatient fatal pulmonary embolism

Massive pulmonary embolism (MPE) is an important cause of outpatient sudden death, and description of these patients is critical for identification and treatment. Objective: To test whether MPE patients can be distinguished from patients suffering sudden death from other causes based on clinical, demographic, and historical data. The hypothesis was that MPE cases would be more likely to manifest components of a clinical triad of 1) overt dyspnea, 2) alteration of mental status or syncope, and 3) shock index (pulse divided by systolic blood pressure) >0.8. Methods: Retrospective case-control study of medical examiner data from 1992 to 1999 including all patients with nontraumatic death, aged 18-65 years, transported to an emergency department, with autopsy-determined cause of death. Analysis was done by 95% confidence interval (95% CI) for difference in proportions and multivariate logistic regression for odds ratios. Results: The MPE patients (n = 37) were younger than the control subjects (n = 347) (40.2 vs 46.5 years, unpaired t-test p < 0.001). At least two of the three components of the triad were present in 56.8% of MPE cases vs 3.5% of controls (95% CI for difference in proportions = 37.3% to 68.0%). Significant variables (and odds ratios) for MPE after multivariate analysis included: dyspnea (13.8), shock index >0.8 (23.6), immobilization or fracture (14.6), seen by a physician within two weeks (5.1), and African American female status (6.4). Conclusions: Patients in this community with fatal MPE were young with risk factors for pulmonary embolism, and commonly manifested components of a triad including: dyspnea, alteration of mental status/syncope, and shock prior to death.