Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jan 1999
Comparative StudyInhibition of nitric oxide metabolism enhances the hypnotic-anesthetic action of the alpha2-adrenoceptor agonist dexmedetomidine in vivo.
Nitric oxide (NO) synthase inhibitors have been demonstrated to increase the anesthetic action of volatile and intravenous anesthetics. This study was designed to test the hypothesis that, comparable to other general anesthetics, the hypnotic-anesthetic action of dexmedetomidine is increased after administration of the NO synthase inhibitor nitro-L-arginine methyl ester (L-NAME). With approval of the local animal care committee, the anesthetic potency of dexmedetomidine or a combination of dexmedetomidine plus 1 mM L-NAME was determined in Xenopus laevis larvae. ⋯ Administration of D-NAME did not affect the EC50 of dexmedetomidine. In a manner comparable to that of other general anesthetics, the anesthetic effect of dexmedetomidine was increased by about 51% by an acute inhibition of the NO metabolism. Together with recent findings that alpha2-adrenoceptor agonists decrease the NO mediated synthesis of cGMP similar to volatile and intravenous anesthetics, the results suggest that the NO/cGMP pathway is an important mediator of the anesthetic action of these compounds.
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J Neurosurg Anesthesiol · Jan 1999
Case ReportsSpinal anesthesia for nonpulmonary surgery in a lung transplant recipient.
The anesthetic implications for patients requiring anesthesia for surgery after lung transplantation have not been thoroughly studied. The use of spinal anesthesia in patients undergoing lumbar laminectomy has been well described. This case demonstrates the use of spinal anesthesia for lumbar laminectomy in a patient who had previously undergone a bilateral lung transplantation. Spinal anesthesia was used to minimize the risk of respiratory complications such as aspiration, atelectasis, and pneumonia that may be associated with administration of a general anesthetic.
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J Neurosurg Anesthesiol · Jan 1999
Is there paradoxical arousal reaction in the EEG subdelta range in patients during anesthesia?
Different anesthetic drugs can produce different electroencephalographic (EEG) patterns. Nondrug induced influences, such as surgical stimulation, may also alter the EEG in anesthetized patients. Increases of delta activity are interpreted as signs of deepening of anesthesia. ⋯ On the other hand, in the subdelta range (the 0.05-1 Hz and 1-2 Hz frequency bands), there was an opposite reaction. This significant (p<0.001, according to ANOVA and Dunn's method) reduction of EEG power as a result of the surgical stimuli was found in 25 patients (mean age, 49.1+/-16.3 years) scheduled for elective neurosurgical intervention in the lumbosacral region. This report shows some of the problems arising from the common practice of arbitrarily subdividing a power spectrum in frequency bands.
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J Neurosurg Anesthesiol · Jan 1999
Effect of inhalational anesthesia on cerebral circulation in Moyamoya disease.
To clarify the effects of inhalational anesthesia on cerebral circulation in patients with Moyamoya disease, the authors measured regional cortical blood flow (CoBF), jugular bulb oxygen saturation (SjO2), and frontal regional oxygen saturation (rSO2) by near infra-red spectroscopy under total intravenous and inhalational anesthesia in 13 patients undergoing revascularization procedures. Cortical blood flow decreased in some regions under inhaled anesthesia in all cases, and the mean value decreased significantly (p<0.01). ⋯ Regional CoBF levels may be decreased by inhaled anesthesia in patients with Moyamoya disease, and such anesthesia may provoke intracerebral steal. Total intravenous anesthesia, however, lacked these effects.
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J Neurosurg Anesthesiol · Jan 1999
Comparative StudyEffects of postischemic halothane administration on outcome from transient focal cerebral ischemia in the rat.
This study examined the effect of prolonged postischemic halothane administration on outcome from transient focal cerebral ischemia in rats. Conscious normothermic rats were subjected to 75 minutes of filament middle cerebral artery occlusion (MCAO). Animals were then divided into two groups. ⋯ Cortical (Awake = 76+/-57 mm3; Halothane = 90+/-57 mm3; p = 0.494, mean +/- standard deviation), subcortical (Awake = 71+/-33 mm3; Halothane = 80+/-35 mm3; p = 0.472), and total (Awake = 147+/-88 mm3; Halothane = 171+/-91 mm3; p = 0.477) infarct volumes were not significantly different between groups. The data indicate that postischemic halothane administration offers no benefit in ameliorating damage from focal cerebral ischemia. This suggests that the neuroprotective effect of halothane observed in other studies is consistent with influences on intra-ischemic pathophysiology only.