Anesthesiology
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Recent studies have questioned the classical gravitational model of pulmonary perfusion. Because the lateral position is commonly used during surgery, the authors studied the redistribution of pulmonary blood flow in the left lateral decubitus position using a high spatial resolution technique. ⋯ Perfusion to each lung did not change with movement from the supine to the left lateral position. These findings contradict the prediction of increased dependent lung and decreased nondependent lung blood flow based on the gravitational model. It was concluded that the distribution of blood flow in the lateral position in dogs is dominated by pulmonary vascular structure.
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Changes in pulmonary edema infiltration and surfactant after intermittent positive pressure ventilation with high peak inspiratory lung volumes have been well described. To further elucidate the role of surfactant changes, the authors tested the effect of different doses of exogenous surfactant preceding high peak inspiratory lung volumes on lung function and lung permeability. ⋯ Exogenous surfactant preceding high peak inspiratory lung volumes prevents impairment of oxygenation, lung mechanics, and minimal surface tension of bronchoalveolar lavage fluid and reduces alveolar influx of Evans blue dye. These data indicate that surfactant has a beneficial effect on ventilation-induced lung injury.
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Pain resulting from a usually nonpainful stimulus (allodynia) is a common characteristic of neuropathic pain. Among animal models of allodynia, tight ligature of lumbar spinal nerves has been of special interest because it has been reported to be relieved by sympathectomy. The purpose of this study was to determine whether spinal analgesic agents, which have opposite effects on sympathetic nervous system activity (clonidine decreases it and neostigmine increases it), have differing efficacy in this model. ⋯ These results disagree with previous observations that mechanical allodynia in this animal model depends on sympathetic nervous system activity. Therefore, intrathecally administered analgesic agents, one that reduces sympathetic outflow from the spinal cord (clonidine) and one that increases it (neostigmine), were similarly effective in this model.
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Case Reports Clinical Trial
Intravenous regional clonidine in the management of sympathetically maintained pain.