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Clinical Signs and Symptoms in Pulmonary Embolism A Reassessment

The clinical diagnosis of pulmonary embolism (PE) remains difficult despite years of investigation. The clinical signs and symptoms of pulmonary embolism are numerous, but they are not diagnostically accurate. Radionuclide ventilation perfusion imaging (VQ) has become an important adjunct in screening patients for suspected PE. This study re-evaluates the predictive capabilities of various clinical signs and symptoms in a population of patients in whom angiography was thought to be necessary because of clinical concern for PE. One hundred one patients with suspected PE were retrospectively identified. Clinical information on them was complete, and laboratory studies, VQ imaging, and pulmonary angiography were performed. Thirty-seven clinical signs, symptoms, and other characteristics were individually compared for patients whose angiographic results were positive or negative for PE. Modifying or interactive effects on PE were then examined with logistic regression analysis. Several clinical conditions, including immobilization and recent surgery, were significantly associated with PE. Shortness of breath and history of smoking were significantly associated with negative results on pulmonary angiography. A “high probability” VQ scan was highly predictive (P < .0001) of positive results on angiography. When interactive factors for PE were examined, lack of shortness of breath and arterial pH ≤ 7.45, lack of shortness of breath and respiratory rate > 23, diaphoresis in a nonsmoker and immobilized female, were significantly associated with PE. This study again documents the difficulty in using clinical criteria—including signs, symptoms, and laboratory determinations—to predict PE accurately, even in a population in which PE was of clinical concern irrespective of the VQ scan results. The extremely high predictive ability of the VQ scan reinforces its importance in the evaluation of the patient with suspected PE.