Anesthesiology
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Nitrous oxide (N2O) and propofol exhibit directionally opposite effects on the cerebral circulation, vasodilation and vasoconstriction, respectively. The authors investigated an interaction between the two anesthetic agents on the dynamic cerebrovascular response to step changes in end-tidal pressure of carbon dioxide (PetCO2) in humans. ⋯ Propofol and N2O, when one is added to the other, produce similar dynamic FV(MCA) responses to sudden changes in PetCO2. Addition of each anesthetic slows the dynamic response and produces the response whose magnitude is proportional to the baseline FV(MCA).
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Adenosine triphosphate-regulated potassium channels mediate protection against myocardial infarction produced by volatile anesthetics and opioids. We tested the hypothesis that morphine enhances the protective effect of isoflurane by activating mitochondrial adenosine triphosphate-regulated potassium channels and opioid receptors. ⋯ Combined administration of isoflurane and morphine enhances the protection against myocardial infarction to a greater extent than either drug alone. This beneficial effect is mediated by mitochondrial adenosine triphosphate-regulated potassium channels and opioid receptors in vivo.
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Every approach to the sciatic nerve in the buttocks currently requires the identification of pelvic bone structures. The large size of the nerve and its constant trajectory suggest that a simplified approach is possible. ⋯ Because of the intimate relationship of the sciatic nerve to the bony pelvis, the position of this nerve in the buttocks is constant. Caudal to the piriformis muscle the nerve runs vertically between the ischium and the greater trochanter. The location of this narrow passage, not the buttocks' size, determines the position of the nerve. While the size of the buttocks is variable among different individuals and in the same individual at different stages of adult life, the relationship of the sciatic nerve to the pelvis is constant throughout life. Using this relationship to our advantage, a sciatic block in adults can be accomplished at 10 cm lateral to the intergluteal sulcus without a need for identification of buried structures or line tracings.
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Gabapentin has recently been used clinically as an antihyperalgesic agent to treat certain neuropathic pain states. The aim of this study is to test whether gabapentin is able to inhibit responses to peritoneal irritation-induced visceral pain and to examine the effect of gabapentin on spinal cord amino acid release. ⋯ These data demonstrate that gabapentin effectively inhibits acetic acid-induced nociception, and the antinociceptive effect of gabapentin correlates with the suppression of noxious-evoked release of excitatory amino acids in the spinal cord.
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With clinical data suggesting a role for excitatory amino acid neurotransmission in the pathogenesis of cardiopulmonary bypass (CPB)-associated brain injury, the current study was designed to determine whether xenon, an N-methyl-D-aspartate receptor antagonist, would attenuate CPB-induced neurologic and neurocognitive dysfunction in the rat. ⋯ These data indicate that CPB-induced neurologic and neurocognitive dysfunction can be attenuated by the administration of xenon, potentially related to its neuroprotective effect via N-methyl-D-aspartate receptor antagonism.