Page 125 - Critical Care Notes

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from hypoxemia or acidosis, and congenital heart disease. Idiopathic causes → pri-
mary PAH.
Hypoxemia → hypertrophy of smooth muscle in pulmonary arteries →↑
lumen vessel size → vasoconstriction → narrow of artery vessels → resistance
to blood flow → RV pumps harder to move blood across the resistance →↑ pul-
monary vascular resistance →↑ RV workload → smooth muscle proliferated →
vascular obliteration → luminal obstruction →↑ pulmonary artery pressure and
PVR → RV hypertrophy, right heart dilation → RV cardiac function → RV failure.
Acute PAH → cor pulmonale and may be the result of a massive pulmonary
embolism.
Clinical Presentation
■ Increased mean right atrial and RV pressure, decreased cardiac index,
increased PAP m
■ ECG: Increased P-wave amplitude (lead II), incomplete right bundle branch
block (RBBB), tall right precordial R waves, right axis deviation, and RV strain
■ Hypoxemia, central cyanosis
■ Labored and painful breathing, crackles, wheezing; possible pleural effusion
■ JVD, liver engorgement and hepatomegaly, ascites
■ Atrial gallop, splitting of S 2 or increased S 2 intensity, S 3 or S 4 , ejection click
■ Tachycardia, weak pulse, heart palpitations, angina-like chest pain
■ LVF: SOB, DOE, hypoventilation, tachypnea, coughing, fatigue, syncope,
hypotension, decreased urinary output, decreased cardiac output, shock
■ RVF: Peripheral and dependent edema, weight gain, tricuspid regurgitation,
JVD, prominent heave over RV palpated
■ Hoarseness if pressure on left recurrent laryngeal nerve
■ Anorexia; right upper quadrant pain, epigastric distress
■ Fatigue, weakness, drowsiness, restlessness, agitation, confusion
Diagnostic Tests
■ Electrocardiogram showing RV hypertrophy, right axis deviation
■ Two-dimensional echocardiogram with Doppler flow
■ CXR or CT
■ Polysomnography for PAH sleep-disordered breathing
· ·
■ V/Q scan—Contraindicated in patients with primary pulmonary hypertension
■ Pulmonary angiography with right-sided heart catheterization
■ Pulmonary function tests
■ ABGs, CBC
■ Autoantibody tests, HIV, liver function tests
Management
■ Therapy depends on the stage of the disease and precipitating cause of PAH.
■ There are no clear guidelines for the management of patients with PAH and
progressive right HF.
■ Patients with PAH need to be in a center with specific pulmonologist expert-
ise in managing the disease.
RESP