MONITORING OF HEPATIC VENOUS OXYGEN-SATURATION FOR PREDICTING ACUTE LIVER DYSFUNCTION AFTER FONTAN OPERATIONS

Acute liver dysfunction after Fontan operations may result from inadeq uate hepatic perfusion along with low cardiac output and high central venous pressure. We monitored hepatic venous oxygen saturation in 15 p atients after Fontan operations to determine whether oxygen saturation predicts the occurrence and severity of acute liver dysfunction. We m easured oxygen saturation from hepatic venous blood samples every 4 to 5 hours for at least 24 hours after the operation and used the mean h epatic venous oxygen saturation value for the first 24 hours after the operation to analyze the relationship between oxygen saturation and h epatic function. As indices of hepatic function, we measured serum ala nine aminotransferase, total bilirubin, blood lactate (arterial, hepat ic venous, and the difference between them), and the arterial ketone b ody ratio (the ratio of aceto-acetate to P-hydroxybutyrate). For alani ne aminotransferase and bilirubin, we used the maximal values during t he first week in the analysis, and for blood lactate and ketone body r atio, we used the mean values for the first 24 hours after the operati on. Significant broken-line regression relationships existed between m ean hepatic venous oxygen saturation and hepatic function indices (ala nine aminotransferase, total bilirubin, and blood lactate). The interp retation of these relationships is that hepatic indices are constant a bove the critical mean hepatic venous oxygen saturation values but are correlated with mean hepatic venous oxygen saturation below critical points in the range of 21% to 26%. Thus a hepatic venous oxygen satura tion value below about 25% during the first 24 hours after a Fontan op eration predicts the occurrence and the severity of acute liver dysfun ction. We suggest that monitoring hepatic venous oxygen saturation is useful for management of critically ill patients after Fontan operatio ns.