Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1982
Hepatic centrilobular necrosis in rats after exposure to halothane, enflurane, or isoflurane.
Exposure of phenobarbital-pretreated rats to low concentrations of halothane (0.5%) and reduced oxygen tension (FIO2 0.08) resulted in the development of liver necrosis in 51% of the animals. Fasting of rats for 24 hours before the same type of exposure increased the incidence of liver necrosis to 80%. Exposure of fed rats to enflurane (1.5%) and isoflurane (1.4%) in conjunction with low oxygen tensions resulted in no liver necrosis; however, in fasting animals, these same concentrations, when accompanied by low oxygen concentrations, produced an incidence of liver necrosis of 35% and 80%, respectively. ⋯ In this study, in addition to increasing the incidence of toxicity, fasting reduced the glutathione levels and also increased cytochrome P-450 concentrations. Exposure to halothane and to isoflurane, but not to enflurane, further decreased the glutathione level. Perhaps the mechanism of liver toxicity associated with anesthesia, at least in this animal model, is related more directly to severe hypoxia than to a direct toxic intermediate produced as a result of metabolism.
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Anesthesia and analgesia · Sep 1982
Comparative StudyComparison of venous admixture during high-frequency ventilation and conventional ventilation in oleic acid-induced pulmonary edema in dogs.
High-frequency jet ventilation (HFJV) was compared with conventional ventilation ventilation during oleic acid-induced pulmonary edema in dogs. HFJV, when combined with positive end-expiratory pressure (PEEP), returned arterial PO2 (PAO2) and venous admixture to preoleic acid levels, even with tidal volumes as low as 4.8 ml/kg and rates of 300 min-1. When HFJV was compared with conventional (low-frequency, high tidal volume) ventilation at the same Flo2 and level of PEEP, Pao2 was lower and venous admixture higher with HFJV. ⋯ At each level of PEEP, cardiac and stroke indices were not different between the two methods of ventilation. The ability to eliminate CO2 with lower peak airway pressures or to increase PEEP without further increases in peak airway pressure are the primary advantages of HFJV during severe lung injury. Oxygenation is as efficient during HFJV as during conventional ventilation in this model of pulmonary edema when comparisons are made at the same peak airway pressure, but less efficient at the same PEEP.
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Anesthesia and analgesia · Sep 1982
Comparative StudyComparative cardiovascular effects of midazolam and thiopental in healthy patients.
Midazolam, a water-soluble benzodiazepine that is shorter-acting, more potent, and less irritating to veins than diazepam, has been suggested for use for induction of anesthesia. The cardiovascular effects of an induction-sized dose (0.25 mg/kg) of midazolam in A. S. ⋯ Midazolam is, then, as acceptable for induction of anesthesia as thiopental from a hemodynamic point of view in A. S. A. class I and II patients.