Table 1.

Diagnostic criteria for hepatopulmonary syndrome

Physiologic abnormality	Diagnostic criteria
Impaired gas exchange	Arterial blood gas sampling while breathing ambient air with: PaO2 <80 mm Hg or Alveolar-arterial oxygen gradient ≥15 mm Hg if age <65 years, or ≥20 mm Hg if age ≥ 65 years*
Intrapulmonary shunting	Transthoracic echocardiogram with agitated saline demonstrating “late passage” (after >3 cardiac cycles) of bubbles into left atrium Radiolabeled macro-aggregated albumin scan with a brain shunt fraction of >6%
Liver disease	Cirrhosis and/or portal hypertension†
Liver disease	No specific defined testing required, but other causes of hypoxemia must be ruled out ‡

^*AaPO₂ = (FiO₂ [P_atm – PH₂O] – [PCO₂/0.8]) – PaO₂, where PaO₂ represents partial pressure of arterial oxygen, FiO₂ fraction of inspired oxygen, P_atm atmospheric pressure, PH₂O partial pressure of water vapor at body temperature, and PaCO₂ partial pressure of arterial carbon dioxide (0.8 corresponds to the standard gas-exchange respiratory ratio at rest)

^†Patients may have acute and/or chronic hepatitis in the absence of cirrhosis and/or portal hypertension, although nearly all patients with HPS have cirrhosis

^‡Testing may include high-resolution pulmonary CT scanning to assess for parenchymal abnormalities, or pulmonary function testing to evaluate for obstructive or restrictive defects.