Kinetics of [14C]cholic acid in fulminant hepatic failure: a prognostic test.

The kinetics of intravenously injected [14C]cholic acid have been investigated in 14 patients with fulminant hepatic failure, 24 to 36 hr after the development of grade IV encephalopathy. Radioactivity was measured in plasma samples and in the individual plasma bile acid fractions after separation by thin layer chromatography. Plasma disappearance curves of the free [14C]cholic acid were calculated by an iterative nonlinear least squares fitting procedure using a computer. The disappearance of total plasma radioactivity was similar in all patients and greatly prolonged compared with healthy subjects. However, the plasma disappearance of free [14C]cholic acid was significantly faster in the 8 patients who recovered consciousness than in the 6 who did not. Plasma disappearance of free [14C]cholic acid correlated highly significantly with the proportion of conjugated [14C]cholate in plasma. All patients in whom more than 70% of plasma radioactivity was in the conjugated fraction 3 hr after injection survived and left hospital, whereas all of those in whom less than 55% was conjugated died. Measuring the percentage conjugation of [14C]cholate 3 hr after injection may therefore be a useful test of residual liver function in hepatic failure, as a guide to prognosis and in evaluating new forms of treatment.