Masui. The Japanese journal of anesthesiology
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Randomized Controlled Trial Clinical Trial
[The effects of preanesthetic oral clonidine upon heart rate response to intravenous atropine in patients during general anesthesia].
In awake subjects the positive chronotropic effect of intravenously administered atropine 10 micrograms.kg-1 has been demonstrated to be blunted by preanesthetic medication of oral clonidine 5 micrograms.kg-1. The aim of the present study is to investigate whether general anesthesia could alter the clonidine-induced attenuation of positive chronotropic effect by atropine. Thirty-two patients were randomly assigned to one of the two groups; patients of the clonidine group received oral clonidine 5 micrograms.kg-1 (n = 12), whereas those of the control group received no clonidine. ⋯ Following the stable circulatory period of 10 min, hemodynamic measurements were made at 1 min intervals for 10 min after atropine 10 micrograms.kg-1 was administered intravenously as a bolus in both groups. A significant attenuation in heart rate response to intravenous atropine 10 micrograms.kg-1 was observed in patients receiving clonidine 5 micrograms.kg-1, as compared with that in the control group (P less than 0.01); maximal increases in heart rate were 15 +/- 8 and 22 +/- 6 beats.min-1 (mean +/- SD) in the clonidine and control groups, respectively. It is concluded that clonidine 5 micrograms.kg-1 blunts the heart rate response to intravenous atropine 10 micrograms.kg-1 in patients anesthetized with enflurane and nitrous oxide in oxygen.
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We evaluated the neuromuscular blocking effect of ORG9426, a new non-depolarizing muscle relaxant, and its recovery by means of washout or by antagonists in vitro, using phrenic nerve-hemidiaphragm preparations of rats. IC50 and IC90 of ORG9426 in single twitch were 10.62 +/- 0.58 microM and 15.75 +/- 0.95 microM; and those in train of four ratio were 9.04 +/- 0.38 microM and 11.87 +/- 0.42 microM, respectively. ⋯ There was no difference between ORG9426 and vecuronium in the recovery from block with washout, neostigmine, 4-aminopyridine, 3, 4-diaminopyridine, and edrophonium. In conclusion, the potency of ORG9426 is relatively low, and it can be easily antagonized by anti-cholinesterases and aminopyridines.
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We studied the effect of a low-dose intrathecal morphine (0.1 or 0.2 mg) in postoperative pain relief and the incidence of side effects. Two hundred and fifteen patients scheduled for transvaginal hysterectomy were divided into 3 groups according to intrathecal morphine doses: M1 (morphine 0.1 mg N = 75), M2 (morphine 0.2 mg N = 69) and C (control N = 71). A standard mid-line lumbar puncture was performed using a 25-gauze needle in the L3/4 interspace. ⋯ Respiratory depression was not seen in any groups. The incidence of vomiting was about 40% in all groups. We conclude that intrathecal morphine 0.1-0.2 mg is useful for pain relief after transvaginal hysterectomy and accompanies no major side effects.
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Comparative Study
[The anesthetic effects of steroids and their actions on the properties of model membrane].
The action of anesthetic steroid on the GABAA receptor in the postsynaptic membrane has been suggested as a mechanism of steroid anesthesia. Alphaxalone, the main component of althesin, is a strong anesthetic, whereas its analogue, delta 16-alphaxalone is not. The only structural difference between the two is a presence of the double bond in the D ring of delta 16-alphaxalone. ⋯ It also showed a weak effect on the phase-transition temperature and the hydrogen bond breaking activity. These changes in the membrane properties correlated to the anesthetic potency. These results suggest that anesthetic potency of steroids is related to their action in destabilizing the structures of the water molecules in the macromolecule-water interface and the macromolecules.
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Comparative Study
[Interaction of nicardipine and inhalational anesthetics--comparison between enflurane and isoflurane].
The effects of nicardipine 1 mg bolus injection under enflurane anesthesia were compared with those under isoflurane anesthesia. Twelve neurosurgical patients were divided into 2 groups, enflurane group (n = 6) and isoflurane group (n = 6). In all patients anesthesia was induced with midazolam, thiamylal, fentanyl and vecuronium. ⋯ In isoflurane group, BP decreased more and longer, and increases of HR and serum concentration of catecholamine continued longer compared with enflurane group. Elimination half life of nicardipine was shorter, area under the curve (AUC) was smaller and clearance of nicardipine was larger in isoflurane group than in enflurane group. It was concluded that isoflurane increased the effects of nicardipine, which were BP depression and reflex sympathetic stimulation, than enflurane and that metabolism and elimination of nicardipine were accelerated more by isoflurane than by enflurane.