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Background and Objectives: Mechanisms of the development of hypoxemia in cirrhosis are still not well understood. In this study, we aimed to investigate and determine the factors contributing to hypoxemia in patients with cirrhosis.
Patients and Measurements: A total of 52 biopsy proven cirrhotic patients without any cardiopulmonary disorder and encephalopathy were studied prospectively. Blood gases were measured in supine, sitting positions and also while inhaling 100% Of for 15 minutes. In the supine position, PaC^ values between 79-60 mmHg were evaluated as mild to moderate hypoxemia and any value below 60 mmHg as severe. Hemoglobin, albumin, AST and ALT levels, prothrombin time, presence of orthodeoxia, ascites, results of spirometric tests, duration of the disease and smoking habits were recorded in all patients. Contrast echocardiography (CE) was also performed in all patients. The results of these parameters were analysed to elucidate the determinants of hypoxemia in cirrhosis.
Results: Twenty-one of the patients (43.8%) were found to be hypoxemic. Hypoxemia was mild to moderate in 18 patients (mean 72.3 mmHg) and severe in 3 patients (mean 52.2 mmHg). All patients responded well to 100% O2 inhalation with expected elevations in PaC>2, thus excluding real anatomic and portopulmonary shunts as the causes of hypoxemia. Hypoxemic patients showed significant differences from normoxemic patients with cirrhosis in frequency of ascites (p<0.001) and AST levels (relatively lower levels) (p<0.05). Positive CE findings and orthodeoxia (a sign representatives of hepatopulmonary syndrome) showed an association with severe hypoxemia (p<0.001 and p<0.01 respectively).
Conclusion: Presence of ascites and relatively low levels of serum AST appear to be predictors of hypoxemia in cirrhotic patients without cardiopulmonary disorder or encephalopathy. We suggest that all cirrhotic patients meeting one or both of these criteria be routinely investigated for hypoxemia.