Etiology and frequency of gas exchange abnormalities in cirrhosis

OBJECTIVE: gas exchange abnormalities are frequent in cirrhosis. These abno rmalities can be considered an indication or contraindication for liver tra nsplantation. The aim of this study was to investigate the etiology and fre quency of these alterations. METHOD: seventy-eight patients with cirrhosis and 20 healthy subjects were selected randomly. Arterial basal blood gases, diffusing capacity of carbon monoxide (DLco), pulmonary function test (PFT) and contrast transthoracic echocardiography (CTTE) with 0.9% saline were done. RESULTS: patients showed lower DLco (79 +/- 23.2 vs 96 +/- 20; p < 0.01), l ower PaCO2 levels (32.2 +/- 4.5 vs 37.5 +/- 4; p < 0.001) and higher alveol ar-arterial oxygen difference (AaPaO(2)) (22.5 +/- 11.4 vs 12 +/- 7.4; p < 0.001) than controls, but the difference between groups in mean PaO2 levels was not significant. Twenty-three patients (29.5%) had pulmonary vasodilat ation (PV) and 28 (36%) altered PFT. Hypocapnia was the most frequently obs erved alteration in gas exchange (73.4%). Hypoxemia and decreased DLco were more frequent in the presence of altered PFT than in the presence of PV. B oth PFT abnormalities and PV were associated with increased AaPaO(2). Child stage was higher in patients with PV (7.9 +/- 2.3 vs 9.2 +/- 2; p = 0.01) than in those without PV. CONCLUSIONS: gas exchange abnormalities are frequent in cirrhosis. The most frequent alteration is hypocapnia, which is associated with PV. The main c ause of severe hypoxemia in these patients is PFT abnormality. Pulmonary va sodilatation is more frequent and more severe in patients with advanced hep atocellular dysfunction.