Anesthesiology
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Randomized Controlled Trial Clinical Trial
Effects of bolus administration of ORG-9426 in children during nitrous oxide-halothane anesthesia.
ORG-9426 is a new steroidal nondepolarizing neuromuscular blocking drug. We determined the dose-response relationship of ORG-9426 in 62 children (aged 1-5 yr) during nitrous oxide-halothane anesthesia by means of log-probit transformation and least-squares linear regression of the initial dose and response. Twelve additional patients received a bolus of 600 micrograms/kg (2 X the dose estimated to produce 95% depression of neuromuscular function [ED95]) of ORG-9426. ⋯ Time from administration of 600 micrograms/kg to onset of 90% and 100% neuromuscular block was 0.8 +/- 0.1 (0.5-1.3) and 1.3 +/- 0.2 (0.7-2.8) min. The time to recovery of neuromuscular transmission to 25% (T25) was 26.7 +/- 1.9 (17.2-39.0) min. The recovery index (T25-75) was 11.0 +/- 1.6 (6.0-22.8) min, and the time to complete recovery of the magnitude of the fourth response to a train-of-four stimuli divided by the magnitude of the first response (T4/T1) greater than or equal to 0.75 was 41.9 +/- 3.2 (26.5-57.7) min.(ABSTRACT TRUNCATED AT 250 WORDS)
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Clinical Trial Controlled Clinical Trial
Ventilatory effects of clonidine alone and in the presence of alfentanil, in human volunteers.
Clonidine, an alpha 2-adrenergic agonist, can potentiate opioid-induced analgesia. In a double-blind placebo-controlled study in human volunteers, we sought to determine whether clonidine also potentiates opioid-induced respiratory depression. Hypercapnic ventilatory responses (minute ventilation, mean inspiratory flow rate, and mouth occlusion pressure) were measured in five healthy male volunteers on two separate occasions (with or without clonidine, approximately 3.5 micrograms.kg-1 orally) under the following conditions: baseline, 2 h after clonidine/placebo (alfentanil concentration of 0), and during computer-controlled alfentanil infusions to approximate plasma concentrations of 5, 10, 20, 40, and 80 ng.ml-1. ⋯ The mouth occlusion pressure was not affected by clonidine treatment. Clonidine treatment did not potentiate alfentanil-induced respiratory depression. Although the combination of an opioid and an alpha 2-adrenergic agonist may act synergistically for the analgesic response, there is no synergistic effect by this drug combination on respiratory depression.
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We investigated the feasibility of performing thoracic epidural anesthesia via the caudal approach in 20 children (age 62 +/- 38 months and weight 18.5 +/- 7.3 kg; mean +/- standard deviation). Based on external landmarks, a predetermined length of 24-G epidural catheter (Concord Portex 20/24 microcatheter system) with stylet was passed into the epidural space through a 20-G intravenous catheter inserted through the sacrococcygeal ligament, and a radiograph of the abdomen and chest was obtained. The radiographically determined catheter tip position was within two vertebrae of the target position in 17 of 20 subjects. ⋯ Intraoperative caudal anesthesia and postoperative pain relief were satisfactory in all 20 subjects. We have found it possible to use the caudal approach to thoracic epidural anesthesia in children as old as 10 yr. Ease of removal of the stylet, ease of injection, and negative aspiration and test doses predict successful placement and obviate the need for routine radiographic confirmation of catheter position.