Effect of ethanol on transfer factor: the importance of posture.

Pulmonary diffusing capacity for carbon monoxide (transfer factor, TLCO) is known to be low in alcoholics,' and ethanol may cause a reduction in TLCO in normal subjects.2 The mechanism of this reduction is unclear, but there are two possible explanations. Firstly, a redistribution of blood may occur between the central and peripheral vasculature, causing a fall in pulmonary capillary blood volume (Vc). Secondly, there may be a change in the function of the alveolar capillary membrane (DM). Distinction between these two possibilities is important as it has been claimed on the basis of the alcohol induced reduction in TLCO that ethanol is directly toxic to the pulmonary alveolar capillary membrane.2 To elucidate the mechanism of the fall in TLCO after ethanol we measured TLCO, Vc, and DM in normal subjects in both the erect and supine positions, before and 90 minutes after taking ethanol.