RESUMO
Other investigators have demonstrated halothane-induced hepatic injury in rats anesthetized in hypoxic environments. The authors examined this phenomenon in mice and investigated plasma fluoride levels in mice and rats anesthetized with halothane in 40, 21 and 7 per cent oxygen with or without pretreatment with phenobarbital or carbon tetrachloride. They found no hepatic necrosis in mice. Mice produced less fluoride than rats. This difference in halothane metabolism between Sprague-Dawley rats and Swiss-Webster mice may explain the failure to observe hepatic necrosis in mice.
Assuntos
Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Fluoretos/metabolismo , Halotano/efeitos adversos , Animais , Biotransformação , Tetracloreto de Carbono/farmacologia , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Halotano/metabolismo , Hipóxia/metabolismo , Masculino , Camundongos , Oxigênio/sangue , Fenobarbital/farmacologia , Ratos , Especificidade da Espécie , Tiopental/farmacologiaRESUMO
Closed system anesthesia is economical, minimally, polluting, and conserves a patient's airway heat and moisture. Yet this method of anesthesia is not widely used because it is considered dangerous by many clinicians. We review the origins of that belief and then test the application of 2 schemes for administering potent agents in a closed system with CO2 absorption. We 1st employed Lowe's square-root-of-time uptake model in 30 patients, using halothane or enflurane. We found that the model provided a good starting point for learning to use the closed system. However, anesthetic concentrations were not accurately predicted. Based on our experience with that model, we examined a simpler approach. We began each of 10 anesthetics using a semiclosed system, then closed the system. Only sufficient O2 for metabolic demand and halothane were added to the closed system. The rate of halothane administration was the same for each patient. This approach proved clinically satisfactory, and the measured halothane concentration remained relatively constant during 45 minutes using the closed system. Changing from a semiclosed to a closed system affords the advantages of the closed system 75 percent of the time, yet requires no extra tasks or equipment.
Assuntos
Anestesia por Inalação/métodos , Anestesia/história , Anestesia por Inalação/instrumentação , Dióxido de Carbono/metabolismo , Enflurano , Halotano , História do Século XX , Humanos , Masculino , Modelos Biológicos , Oxigênio , Estados UnidosRESUMO
A sex difference in postanaesthetic mortality after fluroxene anaesthesia was found in Swiss Webster mice. More males succumbed than females. This toxicity was biotransformation-dependent and could be reversed by pretreatment with "opposite" sex hormones. The toxicity of the fluroxene metabolite trifluoroethanol also was more marked in male mice, but was only partially influenced by microsomal enzyme inhibitors or stimulators, or by sex hormones.