Hepatopulmonary Syndrome - Diagnosis and Management Summary A defect in arterial oxygenation due to a gas exchange disorder occurring in the setting of liver disease and in the absence of intrinsic lung disease Caused by intrapulmonary vascular dilation (IVPD) either due to a diffusion-perfusion defect (Type 1) or anatomic shunt (Type 2) Clinical Presentation: • Dyspnea - Common but not specific to HPS alone • Platypnea - Dyspnea worse when sitting upright compared to lying supine • Orthopnea - PaO2 ↓ by ≥ 5% or ≥ 4mmHg from supine to upright position • Hypoxemia - V/Q mismatch and restricted diffusion from IPVDs Diagnostic Testing: • Pulse oximetry - Non-invasive initial screening tool using cutoff SpO2 < 96% detects severe HPS with 100% sens, 88% spec • Contrast-enhanced echocardiography - Assess for IPVD using peripherally injected agitated saline during echocardiography - Microbubbles appear in left heart 3-6 cardiac cycles after right atrial passage • Arterial blood gas (ABC) analysis - Quantifies degree of hypoxemia. Should be performed on room air in seated position after 10 minutes of rest HPS Diagnostic Criteria: • Underlying liver disease - Portal hypertension with or without cirrhosis • Intra-pulmonary vascular dilation - Positive findings on contrast-enhanced TTE. Can also be seen on radioactive lung perfusion scanning or pulmonary angiography (in select patients) • Oxygenation defect - PaO2 < 80mmHg or A-a gradient ≥ 15mmHg (≥ 20mmHg in patients aged 65 and older) on room air Treatment: • There is no established medical therapy for HPS. Supportive care with supplemental oxygen if PaO2 < 60mmHg, goal SpO2 > 88% • Management of underlying portal hypertension • Liver transplantation: results in almost uniform resolution of HPS features - Complete resolution of symptoms may take months after transplant - Lizzie Aby, MD @LizzieAbyMD #hepatopulmonary #syndrome #diagnosis #management #treatment #hepatology
