Purpose: The purpose of this investigation is to determine the characteristics of the history, physical examination, chest radiograph, and ECG, and the ventilation/perfusion (V/Q) lung scan probability in patients with pulmonary embolism (PE) stratified according to their presenting syndrome.
Background: In considering a possible diagnosis of acute PE, it is helpful to consider the patient in terms of the presenting syndrome (pulmonary infarction, isolated dyspnea, or circulatory collapse). In assessing the possibility of acute PE, it would be more useful to know the detailed characteristics of the particular syndrome rather than the clinical characteristics of all patients with PE.
Methods: Patients described in this investigation participated in the national collaborative trial of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED). All had PE diagnosed by pulmonary angiography. None had prior cardiopulmonary disease. All examinations and laboratory tests were obtained within 24 h of the pulmonary angiogram and most were within 12 h of the pulmonary angiogram.
Results: Among patients with the pulmonary infarction syndrome, 14 of 119 (12%) had neither dyspnea nor tachypnea. Some patients with circulatory collapse did not have dyspnea, tachypnea, or pleuritic pain. A normal ECG was more prevalent among patients with pulmonary infarction syndrome, 45 of 97 (46%), than among patients with isolated dyspnea syndrome, 2 of 21 (10%) (p<0.01). A PaO2 >80 mm Hg was also more prevalent in patients with the pulmonary infarction syndrome, 27 of 99 (27%), than in patients with the isolated dyspnea syndrome, 2 of 19 (11%). A high-probability V/Q lung scan was less prevalent among the pulmonary infarction group, 38 of 119 (32%), than the isolated dyspnea group, 20 of 31 (65%) (p<0.001).
Conclusion: Many of the findings in the various syndromes of PE can be understood in terms of the severity of PE as it increases from mild with the pulmonary infarction syndrome to moderate with the isolated dyspnea syndrome to severe with circulatory collapse. The prevalence of various clinical and laboratory characteristics of patients with the syndrome of pulmonary infarction, isolated dyspnea, or circulatory collapse may give clues to the diagnosis or suggest characteristics that may reduce the likelihood of inadvertently discarding the diagnosis of PE.