Journal of anesthesia
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Journal of anesthesia · Sep 1995
N-methyl-D-aspartate receptor agonists and antagonists partially affect the duration of ketamine anesthesia in the rat.
The effects of intracerebroventricular injection of excitatory amino acids which act on the N-Methyl-D-aspartate (NMDA) receptor complex on the duration of loss of righting reflex (DLRR) induced by intravenous injection to ketamine (20 mg/kg) were investigated in rats. Ketamine-induced DLRR was 10.3 min, but NMDA receptor agonistsD-alanine (200 μg) or NMDA (0.15 μg) did not change DLRR. ⋯ The NMDA receptor antagonist 7-chlorokynurenic acid (10 μg) alone prolonged DLRR significantly (16.2 min), but not when combined withD-alanine. These data suggest that NMDA receptor blockade contributes at least partially to the mechanism of ketamine anesthesia.
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Journal of anesthesia · Sep 1995
Comparison of the placental transfer of halothane, enflurane, sevoflurane, and isoflurane during cesarean section.
The concentrations of placental transfer of halothane (H), enflurane (E), sevoflurane (S), and isoflurane (I) were measured in 46 patients during cesarean section. The mean inhalation times of H (0.5%), E (1%), S (0.8%), and I (0.6%) were 13 min 27 s, 13 min 49s, 13 min 20s, and 8 min 8s, respectively. The mean concentrations in the maternal artery (MA) were 5.2mg·dl-1 in H, 12.3 mg·dl-1 in E, 5.2mg·dl-1 in S, and 2.4mg·dl-1 in I. ⋯ The Apgar scores in these four groups were not different from that in the group given only 66% nitrous oxide in oxygen as anesthetic (N2O group). The cardiovascular changes induced by skin incision were bigger in the N2O group than in the other groups. The use of a low concentration of H, E, S, or I is, therefore, suggested to be a useful and acceptable anesthetic method for cesarean section.
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Journal of anesthesia · Sep 1995
Effects of morphine on visceral nociception evoked by colorectal distension in rats: comparative examinations of electrophysiological and behavioral responses.
The purpose of this study was to compare the effects of intravenously administered morphine on electrophysiological and behavioral responses to colorectal distension (CRD) and to examine the influence of noxious stimuli applied to another part of the body (a laminectomy) on the visceromotor response to CRD. The effects of morphine (0.1-6.4 mg·kg-1) were examined in rate anesthetized with pentobarbital. Electrophysiological (n=16) and behavioral experiments (n=47) were done. ⋯ When morphine was administered, the visceromotor thresholds in both groups increased to a similar level. Behavioral and neurophysiological responses to CRD were suppressed in a similar fashion by morphine. Although laminectomy affected the threshold values of CRD for visceromotor responses, the laminectomy per se plays an insignificant role when adequate morphine is administered.
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Journal of anesthesia · Sep 1995
Effect of glucose concentration on the subarachnoid spread of tetracaine in the parturient.
We have studied the effect of glucose concentration on the spread of tetracaine spinal anesthesia in 40 parturient patients. Forty women undergoing cesarean section received a subarachnoid injection of tetracaine 8 mg dissolved in either 5% or 10% glucose solution. ⋯ The cumulative dose of ephedrine was higher with 10% glucose (19 ± 10 mg) than with the 5% glucose (13± 8 mg). In tetracaine spinal anesthesia, the rate of onset of analgesia was faster and the maximum level of analgesia was higher in the 10% glucose solution than in the 5% glucose solution.
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Journal of anesthesia · Sep 1995
Endocrine responses to total intravenous anesthesia with droperidol, fentanyl, and ketamine in cardiac patients.
Ketamine-induced sympathetic stimulation can be inhibited by administration of sedatives such as benzodiazepines, droperidol, or opioids. We have developed total intravenous anesthesia with ketamine in combination with droperidol and fentanyl (DFK) and have used this anesthetic method in more than 4000 surgical cases. In this study, we compared DFK in cardiac surgery with isoflurane-fentanyl anesthesia (AOI-F). ⋯ All hormones were significantly elevated after the end of cardiopulmonary bypass. There were no significant differences in any of the hormones, blood pressure, and heart rate measured at different points in both groups. These results showed that DFK anesthesia as a total intravenous anesthesia deserves to be studied in more depth.