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PULMONARY EMBOLISM
- Pathophysiology: V/Q mismatch, but also, platelet-derived inflammatory mediators open up fenestrations in capillary endothelium leading to global hypoxia
- Definitions:
- Submassive PE = signs of RV strain without hypotension or cardiogenic shock
- Massive PE = RV dysfunction with arterial hypotension or cardiogenic shock
- Diagnosis:
- Most common symptoms: dyspnea, pleuritic chest pain, tachypnea, tachycardia
- Normal O2 sat does NOT mean no PE
- Degree of hypoxemia does NOT correlate with size of PE
- Most common ABG finding: acute respiratory alkalosis
- D-dimer has a low specificity in the ICU setting
- If hemodynamically unstableàBedside echo, LE venous Dopplers, consider treating empirically
- If hemodynamically stable and kidney function allowsàCT-PE
- If hemodynamically stable and CXR normal and/or Cr precludes contrast CTà V/Q scan
- Prognosis: evaluate for right heart dysfunction or injury
- EKG, troponin, NT-pro-BNP (Tulane)/BNP (UMC), Echo, CT (can show dilated RV)
- Risk scores to help with disposition and treatment decisions:
- PESI (Pulmonary Embolism Severity Index) predicts 30-day outcome of patients with PE
- Note: patients with renal failure/severe comorbidities were excluded from the validation study
- POMPE-C Score predicts 30-day mortality for patients with active cancer and PE
- Better for cancer patients than PESI
- RIETE Score stratifies risk of major bleeding with anticoagulation for DVT/PE
- Not yet externally validated
- Treatment:
- Hemodynamically unstableà
- LYSE! 100mg tPA over 2 hours
- Resuscitate: respiratory support as needed, cautious fluids bc of right-sided heart failure, vasopressors
- Anti-coagulate after tPA: heparin (prevents further propagation of clot, and also has anti-inflammatory properties. does not dissolve clot.)
- Hemodynamically stableà Anti-coagulate
- Start anticoagulation within 24 hours
- Heparin may be preferred for several reasons: if considering procedure, concerned for bleeding (quick off-set), decreased bioavailability of enoxaparin d/t subcutaneous fat, kidney dysfunction
- Otherwise can use enoxaparin 1 mg/kg BID
- Consider lysis if there are signs of right-heart strain by BNP, troponin, and Echo (you do not need all 3)
- Enoxaparin preferred over warfarin for cancer-related PE
- Reasons to consider IVC filter:
- Contraindication to anticoagulation
- Recurrent PE despite adequate anticoagulation
- ACCP Consensus conference on antithrombotic therapy: 3 months for provoked PE (surgery, immobilization, estrogen, trauma); 3-6 months for unprovoked; indefinite for non-modifiable risk factor (such as active cancer)
- Hemodynamically unstableà
- PESI (Pulmonary Embolism Severity Index) predicts 30-day outcome of patients with PE
- Most common symptoms: dyspnea, pleuritic chest pain, tachypnea, tachycardia