Abnormalities in maximum flow volume curve and closing volume in patients with hepatic cirrhosis.

Pulmonary functions were measured in 53 patients with hepatic cirrhosis in whom there was no clinical or radiographic evidence of pulmonary involvement. Spirometric tests such as total lung capacity, vital capacity, functional residual capacity, residual volume and forced expiratory volume during one second were within normal ranges, in all subjects. Flow volume curve and closing volume tests, however, were abnormal in the majority. The maximal expiratory flow at 50 per cent of vital capacity was not altered but the maximal expiratory flow at 25 percent of vital capacity was decreased significantly in patients with hepatic cirrhosis. The closing volume in patients with hepatic cirrhosis was also significantly increased. The abnormalities in flow volume curve and closing volume curve were also demonstrated in non-smokers, and at any age, in cases of hepatic cirrhosis. These results suggested that the narrowing or closure in small airways may occur in patients with hepatic cirrhosis. These changes may be due to mechanical compression of small airways but interstitial edema which was induced by presence in the circulating blood of vasoactive substances and endotoxins.