Anesthesiology
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Clinical Trial
The cardiovascular effects of mivacurium chloride (BW B1090U) in patients receiving nitrous oxide-opiate-barbiturate anesthesia.
The dose-effect relationship of mivacurium chloride on arterial blood pressure, heart rate, and plasma histamine was determined in 97 consenting ASA physical status I-II patients receiving nitrous oxide-oxygen-opiate-barbiturate anesthesia. In the absence of surgical stimulation during steady state anesthetic conditions with controlled ventilation, average maximum change in tachograph-counted heart rate was 7% or less after 10-15-s injection of mivacurium at all doses from 0.03 to 0.30 mg/kg. Average peak change in mean arterial pressure measured via radial arterial catheter was 7% or less after all doses from 0.03 to 0.15 mg/kg. ⋯ For example, mean blood pressure decreased an average of 13% after injection of mivacurium 0.25 mg/kg over 10-15 s. In contrast, during administration over 30 and 60 s of this dose, arterial pressure decreased 7.6 and 1.5%, respectively (P less than 0.001, 10-15 s vs. 60-s injection). Average peak histamine level, which increased to 132% of control after administration of 0.25 mg/kg over 10-15 s, did not change after injection over 60 s.(ABSTRACT TRUNCATED AT 250 WORDS)
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The authors determined the pharmacokinetics of sufentanil, 12.5 micrograms.kg-1 iv in patients undergoing elective abdominal aortic surgery. The mean age (+/- SD) of the ten patients was 68.4 +/- 7.9 yr; their mean weight was 74.4 +/- 19.1 kg. Six patients underwent aortobifemoral grafting and four had abdominal aortic aneurysm repair. ⋯ There were no significant correlations between the pharmacokinetic variables and the duration of aortic cross-clamping, the duration of surgery, or the rate or total volume of iv fluids given intraoperatively. In general surgical patients, the mean elimination half-time of sufentanil has been reported to be 2.7 h. When sufentanil is used in large doses as the primary anesthetic agent for patients undergoing abdominal aortic surgery, the long elimination half-time observed implies that recovery will take much longer than would have been anticipated from previously published pharmacokinetic data.
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The actions of two new steroidal nondepolarizing neuromuscular blocking agents, structurally related to vecuronium, have been compared with those of succinylcholine in anesthetized cats and pigs. Both new compounds (Org 7617 and Org 9616) exhibited properties typical of nondepolarizing relaxants in each species. Org 9616 was one-fifth (ED50 cat tibialis 154 micrograms.kg-1) and Org 7617 was one-tenth (ED50 cat tibialis 287 micrograms.kg-1) as potent as vecuronium as a neuromuscular blocking drug. ⋯ Both compounds produced a decrease in arterial blood pressure. This was more pronounced with Org 7617. In addition, Org 9616 produced a slight increase in heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
Absence of agonistic or antagonistic effect of flumazenil (Ro 15-1788) in dogs anesthetized with enflurane, isoflurane, or fentanyl-enflurane.
This study determined the effects of flumazenil on the anesthetic requirements (MAC) of the dog for isoflurane (group 1; n = 6), enflurane (group 2; n = 7), and a combination of fentanyl-enflurane (group 3; n = 6). Control MAC in each group was determined by the tail-clamp method. Each animal in groups 1 and 2 received four iv incremental doses of flumazenil: 0.5, 1.0, 1.5, and 4.5 mg/kg, and isoflurane MAC or enflurane MAC was determined after each dose. ⋯ In group 3, plasma fentanyl concentrations remained stable at 12.5 +/- 3.0 ng/ml (mean +/- SD) throughout the experiment and reduced enflurane MAC by 60 +/- 8%. The addition of flumazenil changed neither the fentanyl concentration in plasma (12.2 +/- 3.8 ng/ml) nor its reduction of enflurane MAC (61 +/- 7%). In conclusion, the absence of effect of flumazenil on the MAC of enflurane, isoflurane, or a fentanyl-enflurane combination suggests that they do not interact with the benzodiazepine receptor.