Anesthesiology
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Randomized Controlled Trial Clinical Trial
Tranexamic acid reduces blood loss, transfusion requirements, and coagulation factor use in primary orthotopic liver transplantation.
Patients with end-stage liver disease frequently incur large-volume blood loss during liver transplantation associated with mechanical factors, preexisting coagulopathy, and intraoperative fibrinolysis. ⋯ High-dose tranexamic acid significantly reduces intraoperative blood loss and perioperative donor exposure in patients with end-stage parenchymal liver disease who are undergoing orthotopic liver transplantation, with marked reductions in platelet and cryoprecipitate requirements.
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Most techniques used to monitor spinal cord tracts are sensitive to the effects of anesthesia, particularly to volatile anesthetic agents. The aim of this prospective study was to show that evoked potentials recorded from the peripheral nerves after spinal cord stimulation, so-called neurogenic motor evoked potentials, are resistant to clinical concentrations of isoflurane or desflurane, compared with somatosensory-evoked potentials. ⋯ Compared with cortical somatosensory-evoked potentials, neurogenic motor-evoked potential signals are well preserved in patients undergoing surgery to correct scoliosis under general anesthesia supplemented with isoflurane or desflurane in concentrations as great as 1 MAC.
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Cocaine use in the United States is prevalent among pregnant women from inner city neighborhoods. To determine the anesthetic implications of cocaine use in parturients undergoing cesarean section delivery, the authors conducted a cohort study. ⋯ Although cocaine-abusing parturients are at higher risk for interim peripartum events such as hypertension, hypotension, and wheezing episodes, there is no significant increase in rates of maternal morbidity or death.
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Nitric oxide (NO), a recognized cell messenger for activating soluble guanylate cyclase, is produced by the enzyme NO synthase in a wide variety of tissues, including vascular endothelium and the central nervous system. The authors previously reported the possible involvement of the NO pathway in the anesthetic state by showing that a specific NO synthase inhibitor, nitroG-L-arginine methyl ester (L-NAME), dose dependently and reversibly decreases the minimum alveolar concentration (MAC) for halothane anesthesia. The availability of a structurally distinct inhibitor selective for the neuronal isoform of NO synthase, 7-nitro indazole (7-NI), allowed for the possibility of dissociating the central nervous system effects of neuronal NO synthase inhibition from the cardiovascular effects of endothelial NO synthase inhibition. ⋯ Inhibition of the NO synthase pathway decreased the MAC for isoflurane, which suggests that inhibition of the NO pathway decreases the level of consciousness and augments sedation, analgesia, and anesthesia. The MAC reduction by two structurally distinct NO synthase inhibitors supports that this is a specific effect on NO synthase. Furthermore, the action of the neuronal NO synthase inhibitor 7-NI supports an effect selective for neuronal NO synthase and also avoids the hypertensive response of generalized NO synthase inhibitors.
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The site where volatile anesthetics inhibit endothelium-dependent, nitric oxide-mediated vasodilation is unclear. To determine whether anesthetics could limit endothelium-dependent nitric oxide production by inhibiting receptor-mediated increases in cytosolic Ca2+, experiments were performed to see if the inhalational anesthetics halothane, isoflurane, and enflurane affect intracellular Ca2+ ([Ca2+]i) transients induced by the agonists bradykinin and adenosine triphosphate in cultured bovine aortic endothelial cells. ⋯ Halothane and enflurane, but not isoflurane, inhibit bradykinin- and adenosine triphosphate-stimulated Ca2+ transients in endothelial cells. Limitations of Ca2+ availability to activate constitutive endothelial nitric oxide synthase could allow for part, but not all, of the inhibition of endothelium-dependent nitric oxide-mediated vasodilation by inhalational anesthetics.