British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Cisatracurium neuromuscular block at the adductor pollicis and the laryngeal adductor muscles in humans.
We have compared the dose-response relationship (n = 30) and time course of neuromuscular block (n = 20) of cisatracurium at the laryngeal adductor and the adductor pollicis muscles. ED95 values for cisatracurium were 66.8 (95% confidence interval 61.3-72.3) micrograms kg-1 at the larynx and 45.2 (42.1-48.3) micrograms kg-1 at the adductor pollicis muscle (P < 0.0001). ⋯ Time to 95% recovery of the first twitch of the TOF was 26.9 (20.1-33.7) min and 45.6 (39.7-51.5) min, respectively (P < 0.0001). We found that the laryngeal adductors were more resistant to the action of cisatracurium than the adductor pollicis muscle, but onset and recovery were faster at the larynx.
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Nefopam is a non-opioid analgesic agent with a central mode of action involving activation of descending pain-modulating pathways and inhibition of synaptosomal uptake of hydroxytryptamine, norepinephrine and dopamine. Adverse effects during therapeutic use and after overdose of nefopam are known to involve the central nervous system (confusion and convulsions), the cardiovascular system (tachycardia and palpitations) and the kidneys (oliguria and renal failure). We report a death after nefopam overdose in a young woman who exhibited many of these features. It is only the second case of death after nefopam overdose in the literature.
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Increased sensitivity to vecuronium has been noted in patients with Duchenne muscular dystrophy. We report the response to vecuronium in a patient with facioscapulohumeral muscular dystrophy (FSHD), an autosomal dominant disorder with an incidence of 10-20 cases per million. ⋯ Onset time and 25% recovery of T1/T0 after the intubating dose of vecuronium were 240 s and 22 min, respectively. Recovery index (spontaneous recovery of T1/T0 from 25% to 75%) was 9 min.
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We have studied relaxation of airway smooth muscle by sevoflurane, desflurane and halothane in the isolated guinea-pig trachea. Ring preparations were mounted in tissue baths filled with physiological salt solution (PSS), aerated continuously with 5% carbon dioxide in oxygen. Electrical field stimulation (EFS) elicited cholinergic contractions that were abolished by tetrodotoxin, indicating nerve-mediated responses. ⋯ We conclude that sevoflurane, desflurane and halothane inhibited postganglionic cholinergic neuroeffector transmission in the trachea. The effect was probably exerted via pre- and postjunctional mechanisms (i.e. inhibition of acetylcholine release and direct muscle actions). Sevoflurane and desflurane were more potent than halothane both pre- and postjunctionally.
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We tested the hypothesis that the pressure exerted by the laryngeal mask airway (LMA) against the pharyngeal mucosa varied with neuromuscular block, mode of ventilation and the respiratory cycle. We studied 20 anaesthetized adult patients. Microchip sensors were attached to a size 5 LMA at locations approximately corresponding to the base of the tongue, hypopharynx, lateral pharynx, oropharynx, posterior pharynx and piriform fossa. ⋯ There were no significant changes in mucosal pressure at any location between the four conditions. There was no variation between inspiration and expiration. With an intracuff pressure of 60 cm H2O in these circumstances, mucosal pressures were much less than considered safe for prolonged tracheal intubation.