1. Pulmonary Embolism

2. Definition: Sudden lodgment of a blood clot in a pulmonary artery with subsequent obstruction of blood supply to the lung parenchyma. Thrombus Stationary clot. Embolus Detached thrombus that occludes a vessel at a distance from the original site. Pulmonary Embolism

3. Etiology & Risk Factors Thrombus from leg Deep Vein Thrombosis – DVT Fat emboli After long bone fractures Air emboli Increased risk with: Hematological disorders (hypercoagulability). Immobilized patients. Hip or knee replacement surgery. Atrial Fibrillation/Flutter

5. Pathology Pulmonary Hemodynamic Changes Disruption of pulmonary blood flow Pulmonary Hypertension (  PVR,  PAP) Pulmonary infarctionPulmonary infarction can occur Lung tissue necrosis deadspaceIncreased alveolar deadspace (high  / ratio) Gas Exchange Alterations Decreased blood flow to lung tissue interferes with pulmonary surfactant. Atelectasis Low / ratio Lung Mechanic changes Bronchial smooth muscle constriction Release of mediators from platelets

6. Saddle Embolism Occurs at a bifurcation of the pulmonary artery

7. Clinical Manifestations Non-specific symptoms with large degree of variability Tachypnea Dyspnea Hypoxemia (variable) Substernal chest discomfort (dull) Cough/hemoptysis Sense of impending doom

8. Diagnosis Extremely difficult to do. Most diagnostic criteria are over 40 years old and have not been critically evaluated. Chest X-ray ECG changes D-dimer (fibrin split products) Lung / scans Normal rules it out; abnormal are less predictable Definitive diagnosis done with pulmonary angiography. High resolution CT scans showing some promise

9. V/Q Scan Ventilation Scan Radioactive Xe 133 Scintillation camera is used during breathing. Perfusion Scan IV injection of radiolabeled particles (isotope) Iodine or technitium 20 – 50 micron particle size Blood flow decreases past the point of the PE.

11. Pulmonary Angiography Procedure Catheter is advanced into the vein Through the right heart and into PA Dye is injected while x-rays are taken PE confirmed by abnormal filling within the artery

13. Assessing for Thrombus Homan’s SignPositive Homan’s Sign Patient assumes a supine position Lifts the leg Dorsiflexes the foot Patient reports leg pain The occurrence of pain is a positive sign

14. Differential Diagnosis Take good history - ask the right questions Rule Out (R/O) Pneumonia Pneumothorax CHF TB MI

15. ABG Small PE Acute alveolar hyperventilation with mild hypoxemia Large PE Acute ventilatory failure with hypoxemia Metabolic Acidosis Anaerobic metabolism & lactic acid production

16. Treatment of PE Preventive measures Low dose of subcutaneous heparin Tight fitting elastic stockings Movement/exercise Oxygen Therapy

17. Treatment of PE Anticoagulation Therapy Heparin (IV) & LMWH (Subcutaneous) Inactivates thrombin and clotting factor X Inhibits platelet aggregation Monitor partial thromboplastin time (PTT or APTT) Warfarin (Coumadin) – oral administration Monitor prothrombin time (PT) Continue for 3-6 months Thrombolytic Agents Urokinase Streptokinase TPA Bleeding Problems

18. Treatment of PE Pulmonary Embolectomy Surgical removal of blood clots from the pulmonary circulation 60% mortality rate Greenfield Filter Placed in Inferior Vena Cava May be left in place; emboli will resolve spontaneously

20. Greenfield Filter