Review Article - Diagnosing pulmonary embolism

Pulmonary embolism (PE) is a common, treatable, highly lethal emergency, which despite advances in diagnostic testing, remains an under diagnosed killer. The mortality rate of diagnosed and treated pulmonary embolism ranges from 3-8%, but increases to about 30% in untreated pulmonary embolism. PE is a part of the spectrum of venousthromboembolic disease and most pulmonary emboli have their origin from clots in the iliac, deep femoral, or popliteal veins. Nonspecific clinical signs and symptoms with low sensitivity and specificity of routine tests such as arterial blood gas, chest roentgenogram and electrocardiogram make the diagnosis of PE very challenging for the clinician. Pulmonary angiography is the gold standard diagnostic test, but this technique is invasive, expensive, not readily available and labor intensive. Diagnostic strategies have revolved around establishing clinical probabilities based on predictive models, then ruling in or ruling out the diagnosis of PE with various tests. The aim of this article was to review the literature and present an evidence- based medicine approach to diagnosis of pulmonary embolism.

Keywords
Duplex ultrasound, computed tomography, pulmonary angiogram, pulmonary embolism, ventilation perfusion scan