This document discusses pulmonary embolism (PE), which refers to obstruction of the pulmonary artery or its branches by a thrombus (blood clot). PE can be caused by factors that increase clotting like surgery, trauma, or heart failure. When a thrombus blocks a pulmonary vessel, it impairs gas exchange and increases pulmonary vascular resistance, raising pressure in the pulmonary artery and overworking the right ventricle. Diagnosis involves tests like ventilation-perfusion scans and treatment focuses on anticoagulation, thrombolytic drugs, or occasionally surgery to remove clots. Nursing care aims to prevent clots, monitor for complications, manage pain and oxygen therapy.