Anesthesiology
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The distribution and elimination of 0.9% saline given by intravenous infusion has not been compared between the conscious state and during inhalational anesthesia. ⋯ In both conscious and anesthetized, mechanically ventilated sheep, infusion of 0.9% saline resulted in minimal expansion of plasma volume over a 3-h interval. In conscious sheep, infused 0.9% saline was rapidly eliminated from the plasma volume by urinary excretion; in contrast, the combination of isoflurane anesthesia and mechanical ventilation reduced urinary excretion and promoted peripheral accumulation of fluid.
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Mannitol and furosemide are used to reduce increased intracranial pressure (ICP) and to reduce brain bulk during neurosurgery. One mechanism by which these changes might occur is via a reduction in brain water content. Although mannitol and furosemide are commonly used in combination, there has been no formal evaluation of the interactive effects of these two drugs on brain water. The effect of mannitol and furosemide alone and in combination on water content of normal rat brain was examined. ⋯ The doses of mannitol and furosemide utilized were much larger than clinically applicable doses and were selected to maximize the ability to detect effect on brain water. The combination of mannitol and furosemide resulted in greater reduction of brain water content than did mannitol alone. Furosemide enhanced the effect of mannitol on plasma osmolality, resulting in a greater reduction of brain water content. Potential interaction (if any) of smaller, clinically used doses of mannitol and furosemide cannot be surmised from the current study.
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Randomized Controlled Trial Clinical Trial
Effects of inspired hypoxic and hypercapnic gas mixtures on cerebral oxygen saturation in neonates with univentricular heart defects.
Neonates with functional single ventricle often require hypoxic or hypercapnic inspired gas mixtures to reduce pulmonary overcirculation and improve systemic perfusion. Although the impact of these treatments on arterial oxygen saturation has been described, the effects on cerebral oxygenation remain uncertain. This study examined the effect of these treatments on cerebral oxygen saturation and systemic hemodynamics. ⋯ Inspired 3% carbon dioxide improved cerebral oxygenation and mean arterial pressure. Treatment with 17% inspired oxygen had no effect on either.
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Randomized Controlled Trial Clinical Trial
Absence of beneficial effect of acute normovolemic hemodilution combined with aprotinin on allogeneic blood transfusion requirements in cardiac surgery.
The efficacy of acute normovolemic hemodilution (ANH) in decreasing allogeneic blood requirements remains controversial during cardiac surgery. ⋯ Hemodilution is not an effective means to lower the risk of allogeneic blood transfusion in elective cardiac surgical patients with normal cardiac function and in the absence of high risk for coronary ischemia, provided standard intraoperative cell saving and high-dose aprotinin are used.