Definition
P.E. is an occlusion of a pulmonary artery(ies) by a blood clot.

Pathogenesis
A fragment of a thrombus usually located in the deep leg veins breaks off and travels to the lung.

Pathology

• Large or small blood clots may occlude major or minor branches of the pulmonary arterial circulation.
• Large emboli may cause acute cor pulmonale.
• Ten percent of emboli cause wedge-shaped hemorrhagic infarctions which extend to the peripheral lung. Refer to Figures 15-5 and 15-6 in your textbook.
• If the cardiovascular function is adequate, the bronchial circulation will maintain tissue viability resulting in hemorrhage but no infarct.

Pathophysiology

• Varies from no consequence to instantaneous death.
• Respiratory compromise: dyspnea, hemoptysis, chest pain.
• Hemodynamic compromise: acute cor pulmonale.