Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + • Deep venous thrombosis (DVT) most common source of pulmonary embolism (PE)• Uncommon causes of embolism include: -Air (complications from central lines)-Fat (long bone fractures, respiratory insufficiency, coagulopathy, encephalopathy, petechiae)-Amniotic (during active labor)-Tumor emboli from RA or inferior vena cava (IVC)• < 10% of PE cause pulmonary infarction• Size and frequency of PE determines disease and outcome• PE obstructing large pulmonary artery: RV failure• PE causes release of vasoactive amines causing severe pulmonary vasoconstriction, increased dead space and hypoxia from right-to-left shunt• Reflex bronchial vasoconstriction common +++ Epidemiology + • 50,000 deaths yearly in United States• Third leading cause of death in hospital patients• Only 30-40% have suspected DVT• PE develops in 60% of untreated proximal lower extremity DVT +++ Symptoms and Signs + • Dyspnea and chest pain (present in 75%)• Tachycardia, tachypnea, altered mental status• Classic triad: Dyspnea, chest pain, hemoptysis (15%)• Pleural rub and S1Q3T3 rarely found +++ Laboratory Findings + • ABG measurement: Hypoxia with respiratory alkalosis• ECG: New onset atrial fibrillation, ST/T wave changes, sinus tachycardia• Elevated D-dimer levels +++ Imaging Findings + • Chest film: Often normal, may show pulmonary cap• ECG: May show atrial fibrillation, ischemic changes, or RV strain (S1Q3T3), but usually only sinus tachycardia.• V̇/Q̇ scan: Sensitivity & specificity of 90%, however, 67% of studies are inconclusive• Spiral CT: More accurate than V̇/Q̇ scan• Magnetic resonance angiography: Excellent sensitivity and specificity• Pulmonary angiogram: Invasive but gold standard + • Evaluate for other causes of chest pain and hypoxia, such as pneumonia• Evaluation may be clouded by other possibilities including postoperative pneumonia, which can make V̇/Q̇ scan nondiagnostic• Spiral CT of chest most sensitive and efficient in postoperative patient + • ABG measurement• Chest film• Duplex Doppler of lower extremity• V̇/Q̇ scan (often inconclusive), cannot be interpreted in face of abnormal chest film• Spiral CT of chest accuracy better than V̇/Q̇ and does not need clinical correlation• Magnetic resonance pulmonary angiogram + • Initial stabilization with pressors and ventilatory support• Start heparin/low-molecular-weight heparin expediently• Consider thrombolytics if large clot burden, sever respiratory compromise, hemodynamic instability +++ Surgery + • IVC filter• Open surgical thrombectomy: High mortality (Trendelenburg procedure)• Catheter-based suction embolectomy: only in experienced operators• Extracorporeal membrane oxygenation (ECMO) can be a last resort in a critical situation +++ Indications + • IVC filter-Contraindication to anticoagulation-Venous thrombosis extension on anticoagulation• Open pulmonary embolectomy-Intractable hemodynamic instability-Thrombolytics inadequate or not available-Rarely indicated or useful +++ Prognosis + • Preventable cause of hospital death +++ Prevention + • DVT prophylaxis ... Your MyAccess profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth