Pulmonary embolism.

It is estimated that 600,000 or more symptomatic episodes of pulmonary embolism occur each year in the United States, and this diagnosis is one that may often be missed. This article provides an appraisal of currently used diagnostic procedures, including laboratory tests, arterial oxygen tension, chest radiography, electrocardiography, lung scanning, and selective pulmonary angiography, and examines the available therapeutic options and their indications.