Hepatic release of fluoride from halothane under hypoxic and non-hypoxic conditions in the dog

Six dogs were subjected to halothane anaesthesia under hypoxic and non-hypoxic conditions. Plasma fluoride levels in hepatic venous and arterial blood, as well as blood flow to the liver, were measured during anaesthesia. The amount of fluoride released by the liver could thus be calculated. Release of fluoride took place in all animals during non-hypoxic halothane anaesthesia. The amount released varied between the individual animals and in three of them it rose further during hypoxic anaesthesia. The occurrence of defluorination of halothane, even under nonhypoxic conditions, may indicate a reductive metabolism in at least some parts of the liver. The significance of this hypothesis is discussed.