• Pathophysiology: The embolic occlusions will decrease total blood flow into the pulmonary circulation, worsening V/Q ratios and increasing pulmonary shunt and hypoxemia. Pulmonary infarction can occur if bronchial circulation is insufficient. Pulmonary hypertension will then develop, which increases right ventricular afterload and potentially cardiovascular collapse if the right heart fails.
• Diagnosis: Clinical manifestations may include tachypnea, tachycardia, dyspnea, chest pain, wheezing or hemoptysis. ABG analysis typically shows mild hypoxemia with respiratory alkalosis. Chest radiography may show a wedge-shaped area of radiolucency, indicating an infarct. Pulmonary angiography is the most accurate means of diagnosing a pulmonary embolism (PE), but pulmonary V/Q or helical computed tomography scans are widely used. An abnormal V/Q scan result will demonstrate normal ventilation with perfusion defects.
• Treatment: Systemic anticoagulation prevents the formation of new blood clots or the extension of existing clots. Pulmonary embolectomy may be indicated for patients with massive embolism and impending cardiovascular collapse.