Anesthesiology
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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.
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Comparative Study
Physical characteristics of and rates of nitrous oxide diffusion into tracheal tube cuffs.
Physical characteristics and time-related volume changes in air-inflated tracheal tube cuffs exposed to nitrous oxide were measured in an environmental chamber. Cuff wall diameter, thickness, residual volume, and length were also measured. Gas volumes in most air-inflated tracheal tube cuffs increased 1.7 to 7 ml within 30 min of exposure to pure nitrous oxide. ⋯ Cuff diameters ranged from 13.8 to 32 mm; thicknesses from .033 to .55 mm; residual volumes from .22 to 19.4 ml; lengths from 23.1 to 49.1 mm. Intracuff volume and pressure increase related to gas diffusion into air-inflated cuffs should be periodically adjusted or pressure automatically controlled during nitrous oxide anesthesia. Large-diameter, thin-walled cuffs are recommended.
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Elective cesarean section was performed in a consecutive series of 30 patients with full-term pregnancies who were not in labor. Epidural (lidocaine, 1.5 per cent, with epinephrine, 1:200,000) and general anesthesia (thiopental, nitrous oxide-oxygen, succinylcholine infusion) was used alternately. Neonatal acid-base values and Apgar scores showed no significant difference between the two anesthetic groups, and most infants were vigorous at birth. ⋯ In the group receiving epidural anesthesia, there was a significant correlation between maternal hypotension and weak rooting and sucking reflexes of the infants during the first two days. All infants of high-risk obstetric patients in the series, independent of anesthetic technique used, had abnormal neurologic activity, as evidenced by either depression of muscle tone and the reflexes or all the tested variables. Neurologic assessment as followed in this series is a sensitive indicator of the effects of fetal stress factors acting during cesarean section.