title: Usefulness of noninvasive diagnostic tools for diagnosis of acute pulmonary embolism in patients with a normal chest radiograph.
abstract: The value of bedside examination and noninvasive tests in the diagnosis of acute pulmonary embolism (PE) among patients with a normal chest radiograph was investigated. Normal chest radiographs were present in 20 of 260 patients (8%) with acute PE and in 113 of 642 (18%) with suspected acute PE, in whom the diagnosis was excluded. A partial pressure of oxygen in arterial blood less than or equal to 70 mm Hg in a dyspneic patient with a normal chest radiograph was more often seen among patients with PE (9 of 17, 53%) than among patients in whom PE was excluded (18 of 93, 19%; p less than 0.01). However, no combinations of blood gases, signs and symptoms were strictly diagnostic. High probability ventilation/perfusion scans among patients with a normal chest radiograph were indicative of PE in only 6 of 9 patients (67%). Among patients with low-probability ventilation/perfusion scans, 8 of 47 (17%) had PE. This study showed that the combination of dyspnea and hypoxia in a patient with a normal chest radiograph is a useful clue to the diagnosis of PE. Although intuition suggested that ventilation/perfusion scans would yield better results in patients with a normal chest radiograph, the ability to diagnose PE by ventilation/perfusion scans in this subset of patients was not enhanced, except by a reduction of the percentage of patients with intermediate probability scans.
authors.affiliation: Henry Ford Hospital, Detroit, Michigan.
authors.forename: P D
authors.initials: PD
authors.lastname: Stein
authors.forename: A
authors.initials: A
authors.lastname: Alavi
authors.forename: A
authors.initials: A
authors.lastname: Gottschalk
authors.forename: C A
authors.initials: CA
authors.lastname: Hales
authors.forename: H A
authors.initials: HA
authors.lastname: Saltzman
authors.forename: C E
authors.initials: CE
authors.lastname: Vreim
authors.forename: J G
authors.initials: JG
authors.lastname: Weg
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D001785:Blood Gas Monitoring, Transcutaneous; D004562:Electrocardiography; D006801:Humans; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D013902:Radiography, Thoracic; D011877:Radionuclide Imaging; D014692:Ventilation-Perfusion Ratio