Anesthesiology
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Cerebral metabolic and vascular effects of hypothermia (30 C) and deep pentobarbital anesthesia, separately and combined, were evaluated in 15 mongrel dogs. External cardiovascular support was not used, and mean arterial blood pressures remained greater than 60 torr. Normothermic deep pentobarbital anesthesia, characterized by an electroencephalographic (EEG) frequency of less than 1 Hz, was associated with 30% decreases in cerebral metabolic rates for oxygen (CMRO2) and glucose (CMRG) from lightly anesthetized control values. ⋯ No alteration in the oxygen-glucose or lactate-glucose index indicative of cerebral hypoxia occurred in any experimental group. This study indicates that barbiturates combined with hypothermia decrease cerebral metabolism to a greater extent than hypothermia or barbiturate alone. When cerebral hypometabolism is therapeutically necessary, barbiturates may be indicated as an adjunct to moderate hypothermia.
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Glutathione depletion following inhalation of halogenated anesthetics was investigated as a possible mechanism of toxic reactions associated with anesthesia. Concentrations of reduced glutathione were measured in the blood, liver, lung and kidney of the mouse after anesthesia with enflurane, fluroxene, halothane, isoflurane, methoxyflurane, or trichloroethylene. The anesthetic had no effect on glutathione concentrations in tissues except when fluroxene was used. ⋯ Glutathione was also depleted in livers and lungs of rats anesthetized with fluroxene (60 and 38 per cent, respectively). In blood of rhesus monkeys anesthetized with fluroxene, glutathione was depleted by only 13 per cent. Extents of glutathione depletion are related to fluroxene toxicities in the three species studied.