Pulmonary function tests may be helpful in the diagnosis of hepatopulmonary syndrome. Findings suggestive of hepatopulmonary syndrome include A decrease in the single-breath diffusing capacity for carbon monoxide (DLCO) suggesting a diffusion impairment as a frequent finding in hepatopulmonary syndrome (occurring in up to 80% of patients). Six minute walk test with and without an oxygen titration can also use as an objective assessment of exercise capacity.

Pulmonary Function Tests

• Usually PFT in HPS patients usually reveal normal flows and lung volumes,

• Pulmonary function testing (PFT) may be helpful in the diagnosis of hepatopulmonary syndrome.
• Findings suggestive of hepatopulmonary syndrome include:

• Diffusion impairment is a frequent finding in HPS, occurring in up to 80% of patients.
• Nevertheless this finding is frequent in people with cirrhosis who do not have HPS as well, (50-70% of cirrhotic patients)
• A decrease in the single-breath diffusing capacity for carbon monoxide (DLCO) (not specific) is the most prevalent finding.
• A mean DLCO of 55% predicted in HPS patients compared to a mean of 72% predicted in people with cirrhosis who do not have HPS .
• Reduced lung volumes might barely be observed in tense ascites or in the presence of pleural effusions due to oncotic pressure disturbance or other reasons. (neither specific nor sensitive)

Six Minute Walk Test With and Without an Oxygen Titration

• Objective assessment of exercise capacity

• A decrease below 88% O2 saturation with exertion calls for an oxygen titration study to identify and match oxygen requirements.

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