Anesthesiology
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Halothane anesthesia administered to enzyme-induced animals in a hypoxic atmosphere consistently produced hepatic necrosis. Rats pretreated with phenobarbital were exposed to hypoxia at varying intervals after administration of halothane, enflurane, or isoflurane anesthesia. Anesthetics were administered at 1 MAC for 2 h. ⋯ The injury score of the enflurane and isoflurane groups were comparable to that of controls. We conclude that the potential for hypoxia-induced liver injury during recovery exists after halothane anesthesia. Neither enflurane nor isoflurane anesthesia produced significant hepatic injury in this model.
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The authors constructed a D-shaped tracheal model with an elastic posterior wall, thus simulating normal tracheal anatomy more closely than previous models. The performance of 9-10 tracheal tube cuffs, of 2-3 different tube sizes (7.0-10.0 mm, ID), from six different manufacturers were tested in the model. Cuff residual volumes ranged from 1.78 to 27.35 ml. ⋯ There was no relationship between cuff brands in the wall pressure required to effect a seal in the model. The authors conclude that intratracheal tubes should have cuffs with large residual volumes. This would permit some latitude in tube size selection while ensuring that a seal could be achieved before the cuff is inflated to its residual volume.