British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Dose-response relationships for neostigmine antagonism of vecuronium-induced neuromuscular block in adults and the elderly.
We have studied the dose-response relationship for neostigmine in 36 adult (ages 18-50 yr) and 36 elderly (ages > 70 yr) subjects during antagonism of neuromuscular block induced by vecuronium. All patients received vecuronium 0.08 mg kg-1 and neuromuscular block was monitored mechanomyo-graphically using the train-of-four (TOF) mode of stimulation. Six patients of each age group were allocated randomly to receive neostigmine 5, 15, 25, 35 or 45 micrograms kg-1 or saline at 10% recovery of T1 (first response in the TOF). ⋯ There was a significant difference (P < 0.05) in the time to spontaneous recovery of T1 to 10% between the adults (24 (SD 5.5) min) and the elderly (33 (7.8) min). Dose-response curves for neostigmine were parallel in the two age groups, but those for the elderly were significantly to the right of the curves for the adults. This suggests an apparently lesser relative potency of neostigmine, or the requirement of a larger dose, in the elderly for attaining antagonism of a moderately intense vecuronium block at the same time as in adults.
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Randomized Controlled Trial Comparative Study Clinical Trial
Pain on injection of propofol: comparison of lignocaine with metoclopramide.
We have conducted a randomized, double-blind study in 255 ASA I and II patients to compare the efficacy of lignocaine and metoclopramide in minimizing the pain of injection of i.v. propofol. When administered immediately before propofol into a dorsal hand vein, compared with placebo both drugs significantly reduced the incidence of pain on subsequent injection of propofol (P < 0.001). Twenty patients who had received metoclopramide (n = 85) experienced pain, compared with 18 who had received lignocaine (n = 85) and 42 who had been pretreated with saline (n = 85).
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We have studied the relative pre- and postjunctional neuromuscular blocking effects of Org 9426 in the isolated rat hemidiaphragm muscle using twitch tension and electrophysiological recording techniques. Postjunctional effects were assessed from decreases in twitch height and from end-plate current amplitude and time constant of decay. ⋯ There were no significant differences between the relative pre- and postjunctional effects of Org 9426 and those of previously studied steroidal neuromuscular blocking compounds. It is concluded, therefore, that the rapid onset and short duration of Org 9426 seen in vivo is not a consequence of a strong prejunctional, relative to postjunctional, blocking effect of the compound.
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Comparative Study
Regurgitation of gastric contents during general anaesthesia using the laryngeal mask airway.
We have investigated the incidence of regurgitation of gastric contents during general anaesthesia administered via a laryngeal mask airway (LMA) or face mask and Guedel airway in 56 patients with no risk factors for regurgitation. Patients swallowed a gelatin capsule containing methylene blue 10 min before induction of anaesthesia. ⋯ No patients in the face mask-Guedel airway group regurgitated dye (P = 0.005). There was no evidence of aspiration of dye.
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The purpose of this study was to identify EEG changes associated with low-dose propofol infusion producing only sedative effects, and to describe the memory effects of low-dose propofol infusion. Ten healthy volunteers underwent EEG monitoring (at Fz, Cz, Pz and Oz electrode sites) before, during and after propofol 0.5 mg kg-1 i.v. bolus and 75 micrograms kg-1 min-1 as an infusion. Mean serum concentration of propofol during infusion was 0.86 (SD 0.14) micrograms ml-1. ⋯ Nine of 10 subjects had partial amnesia for complex visual scenes presented during infusion, recalling less than 50% of the material. Stronger cueing was required to retrieve information presented during propofol infusion, with an increase in mean retrieval time from 95.4 (41.2) s to 426.8 (83.1) s. EEG and memory effects resolved quickly after the end of infusion.(ABSTRACT TRUNCATED AT 250 WORDS)