Anesthesiology
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Comparative Study
Protection with antibody to tumor necrosis factor differs with similarly lethal Escherichia coli versus Staphylococcus aureus pneumonia in rats.
Differing factors may alter the effects of antibody to tumor necrosis factor (TNF) in infection and sepsis. The authors tested whether bacteria type or treatment route alters antibody to TNF in a rat model of bacterial pneumonia. ⋯ Antibody to TNF improved host defense and survival rates with both lethal E. coli and S. aureus pneumonia, but protection was greater with E. coli, where TNF concentrations were higher than with S. aureus. The efficacy of antiinflammatory agents in sepsis may be altered by bacteria type.
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Acceptance of a lower transfusion trigger in the perioperative period requires study of the effects of anesthetic depth on the tolerance to acute isovolemic anemia. Anesthetic agents with negative effects on the cardiovascular system may exert proportionately greater depressant effects on cardiac output response than on tissue oxygen demand, reducing tolerance to acute isovolemic anemia. ⋯ Increased anesthetic depth with halothane or ketamine resulted in a decreased tolerance to acute anemia, as reflected by a significant increase in critical hemoglobin concentration.
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In the face of widespread use of lung-protective, low-volume ventilation in patients with acute lung injury, interest in the recruitment maneuver (RM) is growing. Little is known about lung-morphometric effects of the RM as compared with positive end-expiratory pressure (PEEP) titration (PT) without the RM. ⋯ Compared with PT, the RM resulted in a greater lung volume, better aeration of the most dependent lung, and less regional heterogeneity of aeration. However, the RM tended to induce a greater increase in hyperaerated lung volume than did the PT.
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Despite the extensive use of intrathecal morphine infusion for pain, no systematic safety studies exist on its effects in high concentrations. The authors assessed the effects of morphine and clonidine given 28 days intrathecally in dogs. ⋯ The authors found that high intrathecal morphine concentrations lead to aseptic intrathecal inflammatory masses. The lack of effect of clonidine and the possible suppressive effects of clonidine on the local reaction suggest the utility of such coadministration.
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Intrathecal clonidine reduces tactile allodynia in animal models of neuropathic pain, and this effect is blocked by atropine. However, the role of tonic spinal cholinergic activity and its interaction with alpha2-adrenergic systems in normal and neuropathic conditions and to different sensory methods has not been systematically examined. The authors examined cholinergic receptor involvement in thermal and mechanical sensitivity in normal and neuropathic animals and its interaction with intrathecal clonidine. ⋯ These data suggest that after nerve injury, mechanical but not thermal antinociception from intrathecal clonidine relies on a muscarinic interaction, because only mechanical antinociception was antagonized by atropine. These results do not favor a regulation of nociceptive transmission by a tonic release of acetylcholine in nerve-injured rats.