Unit 2: Pulmonary Embolism Flashcards
Pulmonary embolism (PE)
obstruction of one or more of the branches of the pulmonary artery by particulate matter that has a origin elsewhere in the body
Pulmonary Embolisms (PE) are caused by?
- thrombus or piece of tumor
- amniotic fluid
- air
- fat
Greatest Risk Factor for Pulmonary Embolism (PE)
presence of a deep vein thrombosis (DVT)
What is the major predisposing factor for the development of a DVT?
Virchow’s Triad
- venous stasis
- vessel wall damage
- hypercoagulability
Virchow’s Triad
predisposing factors for development of a DVT
- venous stasis
- vessel wall damage
- hypercoagulability
Most common cause of DVT
immobility
Other Risk Factors for Development of a DVT
- obesity
- smoking
- chronic heart disease
- fracture (hip or leg)
- hip or knee replacement
- major surgery
- major trauma
- spinal cord injury
- hx of previous thromboembolism
- malignancy
Pathophysiology of a Pulmonary Embolism (PE)
- when a blood clot or other particulate matter travels to the lungs, it lodges into the pulmonary artery and blocks blood flow
- obstruction results in an impaired ventilation-to-perfusion ratio (V/Q); described as decreased or blocked flow or perfusion to functioning alveoli
Ventilation-Perfusion mismatch (V/Q mismatch)
a decreased blood flow to functioning alveoli or areas of the lung where gas exchange can take place if perfusion is adequate
Clinical Manifestations of PE
- sudden onset of intense dyspnea, pleuritic chest pain, and tachypnea
- PE suspected in any post-op patient
- Hypotensive and Tachycardic b/c of decreased cardiac output (CO)
- Cerebral perfusion my become compromise; anxious, restless, and/or confused
Common Signs and Symptoms of PE
- dyspnea
- accessory muscle use
- pleuritic chest pain
- tachycardia
- tachypnea
- crackles upon auscultation
- cough
- hemoptysis
- unilateral lower extremity edema d/t presence of a DVT; pain in extremity, w/ redness and warmth
Imaging Studies for PE
- Electrocardiogram (ECG)
- Chest x-ray
- CT of the chest (w/ contrast)
- Ventilation-perfusion scan (V/Q Scan)
- Pulmonary Angiography
- Once patient w/ acute PE is stable, lower extremity venous ultrasound is conducted to determine presence and extent of any DVT
What is the initial study for any patient present w/ chest pain?
Electrocardiogram (ECG/EKG)
- to r/o MI
- ischemic changes may be seen (ST changes [depression])
Imaging: Chest X-ray
to r/o other causes of respiratory distress
Ventilation-perfusion scan (V/Q scan)
- utilized if CT scan not available
- can identify areas of the lungs that are ventilated but not perfusing effectively; indication of obstruction of the pulmonary vasculature
- “high probability” = perfusion mismatch
Most Definitive Test for PE
Pulmonary Angiography
Pulmonary Angiography
most definitive test for PE
- allows for visualization of the pulmonary vasculature; detects any obstruction
- only done if other studies not conclusive and patient is stable
Laboratory Studies for PE
- Plasma D-dimer
- ABGs
- Cardiac studies (BNP)
Plasma D-Dimer
level increases as the body removes clots through lysis as part of the normal clot-removal process
- D-dimer is the fibrin left behind from that lysis
- negative D-dimer r/o possibility of a clot
- positive D-dimer = presence of clot but requires further testing
ABGs
- hypoxemia (PaO2 < 80 mmHg)
- respiratory alkalosis (PaCO2 < 35)
- may later show metabolic acidosis d/t hypoxemia b/c body switches to anaerobic metabolism in face of hypoxemia
Laboratory Tests: Cardiac (BNP)
- BNP may be elevated d/t strain on the ventricles brought on by PE
- BNP is released by overstretched ventricles under physiological stress
- BNP > 100 = Heart Failure (HF)
Normal BNP (Brain Natriuretic Peptide)
less than 100
-BNP is released by overstretched ventricles under physiological stress
Treatments for a Pulmonary Embolism (PE)
-primarily anticoagulation
>Nonsymptomatic:
-Oral factor Xa inhibitor; require no lab monitoring for med; no hospitalization
>Symptomatic:
-w/ any type of PE: blood clot, air, fat, b/c blood clots will adhere to any of those substances making them larger and able to obstruct more blood flow
-IV Heparin w/ a bolus followed by a continuous drip
Anticoagulation
- does not reduce clots, but keeps clot from getting larger
- helps to reduce the formation of other clots
Heparin Therapy
-monitored through aPTT
-prior to therapy; a aPTT is drawn and repeated q 4 to 6 hours to monitor therapy
-therapeutic goal: 1.5 to 2.5 times the normal value or 40 to 90 seconds
-if aPTT is above therapeutic level, rate of infusion is reduced
>Very high aPTT = infusion may be held before restarting to a lower rate
-If aPTT below level, an additional heparin bolus, along w/ increased rate of infusion
-once aPTT in therapeutic range for 2 consecutive iterations, it is evaluated q 12 or 24 hours
-Protamine Sulfate reversal for heparin; be readily available if active bleeding occurs