Pulmonary Embolism Hidden Killer

1. Pulmonary EmbolismHidden Killer Dr. Hatem Said Assistant Professor Anesthesia/ICU Ain Shams University

2. Objectives • Definition • Epidemiology • Pathophysiology • Clinical Picture • Diagnostic Tools • Prophylaxis • Treatment • Conclusion

3. 1-Definition • Pulmonary embolism (PE): is an obstruction of the pulmonary artery or one of its branches by a thrombus (or thrombi) that originates somewhere in the venous system. • Infarction : The pathological changes which develop in the lung as a result of pulmonary embolism • The types of emboli :could be a blood clot (most common), air, fat, amniotic, fluid, and septic (from bacterial invasion of the thrombus).

4. 2-Epidemiology • PE : The cause of, or a major contributory factor to, death in 7-9% of necropsy cases • 650,000 cases in the US each year • 150,000 – 200,000 US deaths each year • Most common preventable cause of hospital death • 3rd most common acute cardiovascular emergency (MI and stroke)

5. 3-Pathophysiology • Source of Thrombosis (Thrombo-embolic) that originates in the venous system and embolizes to the pulmonary arterial circulation • DVT in veins of leg above the knee (>90%) • DVT elsewhere (pelvic, arm, calf veins, etc.) • Cardiac thrombi

8. 3-Pathophysiology • Risk factors for deep venous thromboembolism • Triad of Virchow • Endothelial injury:mainly caused by either direct trauma (severed vein) or local irritation (by chemotherapy, past DVT, phlebitis). • Stasis: mainly caused by heart failure, prolonged immobility. • Hypercoagulation status: inherited :(AT III def., protein C, S deficiency) or acquired:(malignancy, pregnancy, nephritic syndrome, DIC and liver failure.

9. 3-Pathophysiology • Risk Factors:

16. 4-Clinical Picture • Revised Geneva Score (Clinical Prediction)

17. 4-Clinical Picture • Wells Score (Clinical Prediction)

18. 4-Clinical Picture • Most PE are small embolism will reach the periphery of the lung, sometimes producing wedge shaped shadow (pulmonary infarction) on CxR . • A large embolism suddenly obstructing a major pulmonary vessel has marked effects on cardiac function , often associated with anterior chest pain and collapse. • Chronic recurrent pulmonary embolism may develop pulmonary hypertension and right ventricular failure

19. 4-Clinical Picture • SYMPTOMS : Massive PE: • Dyspnea (84%). -Shock. • Pleuritic pain (74%). -Dyspnea, Cyanosis. • Anterior chest pain (68%). -Apprehension, Sweating. • Cough (53%). -Chest pain, Tachycardia, AF • Hemoptysis (30%). • Asymptomatic (10%). • SIGNS: • Tachypnea (70%). • Rales (51%). • Tachycardia (30%). • S4 (24%). • Accentuated P2.

20. 4-Clinical Picture • Differential Diagnosis: • Myocardial Infarction. • Pluerisy/Pericarditis. • Tachyarrhythmia. • Musculoskeletal/rib fracture. • Lobar Collapse secondary to tumor. • Asthma. • Pneumonia. • Pneumothorax. • Perforating Peptic Ulcer. • Acute Pancreatitis. • Differential Diagnosis of Massive Pulmonary Embolism: • Acute pulmonary edema • Cardiac tamponade. • Dissecting Aortic Aneurysm. • Shock/sepsis.

21. 5-Diagnostic Tools Duplex US with compression of the lower extremities • Non-invasive test that accurately detects proximal DVT in LE (70-80% of pts with PE have concomitant proximal DVT) • Often used in workup of PE before going to more invasive procedures • Invasive test: Venography (definitive diagnosis)

24. 5-Diagnostic Tools • Laboratory Investigations (Non Specific):leukocytosis , ESR elevation, LDH, SGOT elevation with normal bilirubin. • CK, CK MB or Troponin I should be checked to rule out AMI • ABG • Normal does NOT rule out PE • Hypoxia, hypocapnia, respiratory alkalosis. • D-Dimer: High sensitivity but poor specificity • Negative prediction<500 ng /ml is a powerful excluding tool for PE

25. 5-Diagnostic Tools • Chest X-ray: Abnormal in 88% of acute PE • Atelectasis (60-70%): most common finding in PE without infarction. • Westermark sign (increased lucency in area of embolus) • Hampton Hump (wedge-shaped pleural-based infiltrate) • Abrupt cutoff of vessel • Pleural effusion

26. Westermark Sign: represents a focus of oligemia (vasoconstriction )seen distal to a pulmonary embolism

27. Hampton Hump: Radiologic sign which consists of a shallow wedge-shaped opacity in the periphery of the lung with its base against the pleural surface. Occurs 12 to 36 hours after symptoms begin; usually indicates pulmonary infarction

29. 5-Diagnostic Tools • ECG: • Most common: sinus tachycardia +/- nonspecific ST-segment and T-wave changes • “Classic S1-Q3-T3 pattern” • Other signs of right heart strain (ie, new RBBB and ST changes ,T wave inversion in V1,2 • Echocardiography: • It may be helpful after a large PE in a compromised patient, as it can show right heart dilatation , occasionally thrombus and increased pulmonary arterial pressure readings if tricuspid regurgitation developed. • Convenient and rapidly available

30. ECG findings

31. Echocardiography Findings

32. Echocardiography Findings Transesophagealechocardiographic findings showing the floating thrombus (arrow) into central pulmonary artery(PA, pulmonary artery; RA, right atrium; Ao, aorta) Transesophagealechocardiographic shows the reduction in size of the clot (arrow)(PA, pulmonary artery; RA, right atrium; Ao, aorta)

33. Helical(Spiral) CT • Sensitivity 85% (more sensitive for proximal embolibut is less good at detecting peripheral emboli, which may account for up to 30% of PE vessels) • Specificity 95% • It may be used as a first line investigation when V/Q Scan is delayed and when a large PE is suspected and early diagnosis is needed first-

38. V/Q Scan • Identifies mismatches between areas that are ventilated but not perfused • Best initial test in patients with clear CXR • Normal:rules out PE • High-probability scan:is diagnostic of PE if the clinical suspicion is also high • Low-probability scan:rules out PE only in a pt with low pretest clinical probability (because PE is found in roughly 15% of pts with low-probability scans) • Intermediate-probability scan:requires further evaluation (16-66% chance of PE depending on pretest probability)

43. Pulmonary Angiography • “Gold Standard” but is invasive, time consuming, needs experienced radiologists • 5% morbidity • < 0.5% mortality • Indicated if the diagnosis remains uncertain after noninvasive testing

47. 6- Prophylaxis • Encourage all patients to ambulate as soon as possible • determine patient at risk: • Low risk :(<40 years old, ambulating, minor surgery) don't need prophylaxis. • Moderate risk: (>40 years old, abdominal, pelvic or thoracic surgery) pneumatic compression, or low dose heparin prophylaxis. • High risk: (>60years old, prior DVT or PE malignancy, orthopedic surgery hypercoagulability state) combination of pneumatic compression and low dose heparin prophylaxis or Dextran. Coumadine or IVC filter are considered.

48. IVC Filter: if anticoagulation is contraindicated (e.g., active GI bleed, intracranial neoplasm, Ophthalmology patient , known bleeding diathesis), if thrombus formed despite adequate anticoagulation, or with a large burden of thrombosis in the LE that could be fatal if embolized.