Use of automated, on-line pyruvate analysis.

Normothermic blood perfusions of isolated canine liver were undertaken to determine the most sensitive and reliable indicators of viability. Perfusate flow rates and arterial and portal venous pressures were monitored. Arterial and venous concentrations of potassium, pyruvate, serum glutamic oxaloacetic transaminase, and oxygen were monitored and the values stored on magnetic tape for computerized calculation of outputs. Continuous evaluation of taurocholate concentration in the perfusate allowed adjustment of infusion rate to provide a constant flow of bile across the hapatocytes. Pyruvate output, portal venous resistance, serum glutamic oxaloacetic transaminase output and potassium output provided the earliest indices of deterioration. Bile flow and oxygen consumption remained constant until irreversible outflow block had occured. The earliest and most constant parameter signaling deteoration of the ex vivo liver was pyruvate output. The deteriorating liver released pyruvate into the perfusate, while the functioning organ consumed or maintained the available substrate. Since pyruvate output occurs before the onset of irreversible damage, measures can be enacted to reverse the deterioration. Restoration of the preparation can be evaluated through the cessation of pyruvate output.