TOPIC41: pulmonary embolism Flashcards
what is PE?
-Occlusion of one or more arteries by a thrombi that originated elsewhere, typically in the deep veins on the lower extremities/pelvis
Etiology of PE
- DVT (95%)
- Prolonged bed rest, surgery, severe trauma(burns, fractures), congestive HF, oral contraceptives( high estrogen) or hypercoaguable state - upper extremity veins (Central venous catheters)
- Right sided heart chamber dilation.
Risk for PE
- Venous stasis: immobility, surgery, planes, obstruction, CHF
- Vein damage: local trauma, previous thrombosis/phlebitis
- hypercoaguable state
heart and lung signs of PE
after the thrombus blockage: A.lungs: 1. increased pulmonary artery pressure (and resistance) 2.atelectasis 3.decreased surfactant 4.reflex tachypnea 5.hypoxemia
B. heart:
- diminished CO because the blood cannot flow to the left ventricle
- blood will back behind causing cor pulmonale
Signs and symptoms of PE
SMALL EMBOLI: automatically lysed–> no symp.
LARGER: Dyspnea, chest pain, cough, hemoptysis, altered mental status
MASSIVE: hypotension,reflex tachycardia, cyanosis, syncope, cardiac arrest
if VRF: Distended IJV with or without tricuspid regurgitation
DVT: leg edema, tenderness, erythema, pain on flexing ankle
Clinical picture in PE (types according to severity)
- acute massive
- subacute: recurrent emboli
- acute minor: dyspnea, pleuritic pain, hemoptysis, fever
- chronis: PHTN, chronic cor pulmonale
Diagnosis of PE (2 EXCLUSION, 6 SPECIFIC)
A.general for exclusion:
- MI:
- ECG–>tachycardia, S1Q3, right heart strain (repolarisation abnormalities due to hypertrophy or dilation) - aortic dissection:
- CXR:normal or effusion, atelectasis, opacity if infarction
- ABG: decreased pO2, pCO2–> hypoxemia and hypoventillation
B.Specific:
- CT pulm angio
- ventillation/ perfusion lung scan–> detect areas that are ventillated but not perfused
- D-dimer: increased (indicates fibrinolysis)
- lower extremity US
- Troponin is increased if there is right ventricular strain
- BNP: decreased indicates better prognosis than increased (measure level of HF)
Therapy for PE
- Initially:
- supply oxygen
- IV saline (hypotension)
- vasopressors (stop tacchy)
- anticoagulation (stop further coag)
- morphine (stop pain)
2.Consider clot elimination:
a. Embolectomy
b. thrombolytic therapy (with tPA, streptokinase, urokinase eg streptokinase infusion for 24hr + hydrocortisone for side effects)
Heparin should always be added
- Anticoagulation:
- heparin IV 5000units bolus + 1000-2000 units/hr continuous infusion or LMWH subcutaneously (high dose)
- Warfarin for long term 3 weeks to 6 months
Prophylaxis for PE
- compression stockings
- LMWH
- avoid contraceptive pills if at risk
- vena cava filters of limited use