Brain lactate by magnetic resonance spectroscopy during fulminant hepatic failure in the dog

A noninvasive test is needed to assess the severity of encephalopathy during fulminant hepatic failure. This feasibility study was designed to compare a noninvasive test, brain lactate measurement by magnetic resonance spectroscopy, with intracranial pressure monitoring in a large animal model of fulminant hepatic failure. Five dogs received an intraventricular catheter for intracranial pressure measurement. Liver injury was induced by intravenous bolus of D-galactosamine. Brain lactate concentrations were determined by magnetic resonance spectroscopy for up to 48 hours after D-galactosamine administration (t = 0 hour). A dose of D-galactosamine exceeding 1.5 g/kg resulted in fulminant hepatic failure. Brain lactate levels increased to >10 mmol/L in the two dogs that developed severe intracranial hypertension of >50 mm Hg and sustained cerebral perfusion pressures of <40 mm Hg. Both dogs experienced brain death, 42 and 48 hours after the administration of D-galactosamine. Brain lactate concentrations determined by magnetic resonance spectroscopy were in agreement with brain tissue concentrations of lactate determined by high-performance liquid chromatography at necropsy. Plasma lactate concentrations were only mildly elevated (3.2 and 4.2 mmol/L) at the time of brain death. Elevated levels of brain lactate are associated with intracranial hypertension and poor neurological outcome during fulminant hepatic failure. Copyright (C) 1998 by the American Association for the Study of Liver Diseases.