British journal of anaesthesia
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The ventilatory response to carbon dioxide was studied in 12 unpremedicated children, aged 20-68 months, weighing between 10 and 20 kg, under nitrous oxide-halothane anaesthesia. Tidal volume (VT) and end-tidal carbon dioxide tension (PE'CO2) were continuously measured by pneumotachograph and capnograph. Minute ventilation (VE), respiratory rate (f), mean inspiratory flow (Vl) and effective inspiratory cycle (Tl/Ttot) were calculated during anaesthesia at three different inspired halothane concentrations (0.5, 1 and 1.5%). ⋯ When the inspired concentration of halothane was increased, the slope decreased significantly (39% of initial value at 1% inspired halothane, 26% at 1.5%). The addition of carbon dioxide produced significant increases in VE, VT and Vl but no change in respiratory rate. No statistical difference was observed in the slope of carbon dioxide response between the initial and "control" periods which were measured at the same inspired halothane concentration (0.5%).
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of atracurium and alcuronium during halothane anaesthesia by measurement of the train-of-four response of the adductor pollicis muscle and clinical observation.
Atracurium and alcuronium have been compared during halothane anaesthesia, by measurement of the mechanical response of the adductor pollicis muscles to train-of-four stimulation and by clinical observation. Atracurium appeared significantly shorter-acting than alcuronium. However, results suggested that the action of alcuronium may not be of "medium duration". A comparison of three indices of muscle twitch response to the train-of-four nerve stimulation, seemed to indicate that the D'/D ratio gave the best overall index of neuromuscular blockade in this study.
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Randomized Controlled Trial Comparative Study Clinical Trial
Neuromuscular blocking effects of atracurium, vecuronium and pancuronium during bolus and infusion administration.
The potencies of atracurium, vecuronium and pancuronium were compared using bolus injections and continuous infusions. The sizes of the bolus injections were based on previously determined cumulative dose-response relationships. Dose requirements for 90% and 50% sustained blockade were estimated by use of continuous infusion, and the corresponding plasma concentrations were measured for vecuronium and pancuronium. ⋯ This required about 60% of the doses needed for maintenance of 90% response. The relative potency of vecuronium and pancuronium in plasma was 1.1:1. The 25-75% recovery index was significantly shorter for vecuronium than for atracurium.
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An inhibition assay was used to determine quantitatively the allergenic cross-reactivity of some myoneural blocking drugs not yet released for use in Australia, in the sera of patients who had experienced anaphylactic reactions to neuromuscular blocking drugs. Two of the compounds, metocurine and atracurium were highly cross-reactive with the currently used myoneural blockers; fazadinium was weakly cross-reactive and vecuronium intermediate in potency between these two extremes. From these results, we predict that anaphylactic reactions to these compounds, and particularly to metocurine and atracurium, will occur in some patients allergic to the currently used neuromuscular blocking agents.