The aim of this study was to determine whether atracurium-induced neuromuscular block at the laryngeal adductor muscles could be predicted by visual inspection of either adductor pollicis or orbicularis oculi responses. Twenty-one ASA Class I or II patients were anesthetized with propofol (2-2.5 mg/kg) and fentanyl (2-5 micrograms/kg). Tracheal intubation was performed without neuromuscular blocking drugs. Patients were assigned randomly to receive atracurium 0.3 or 0.5 mg/kg intravenously. Train-of-four stimulation was applied to the ulnar, facial, and recurrent laryngeal nerves. Laryngeal response was measured as the pressure change in the tracheal tube cuff positioned between the vocal cords. The response at the adductor pollicis and orbicularis oculi was evaluated visually by two observers who detected if and when block was complete. Twelve patients, including all those receiving 0.5 mg/kg, had complete orbicularis oculi block. The same patients, except one, also had 100% laryngeal block. Adductor pollicis response was abolished in the same 12 patients plus an additional 4 patients. In patients receiving atracurium 0.5 mg/kg, laryngeal and orbicularis oculi responses were abolished faster (mean +/- SD: 132 +/- 80 and 146 +/- 58 s, respectively) than the adductor pollicis muscle (243 +/- 55 s; P < 0.05). There was a significant correlation (r = 0.94; P < 0.001) between neuromuscular block onset time at the laryngeal adductor and orbicularis oculi muscles but not between laryngeal and thumb muscles. The authors conclude that, after injection of atracurium, laryngeal adductor and orbicularis oculi blocks have similar intensities and time courses.(ABSTRACT TRUNCATED AT 250 WORDS)
The potency of vecuronium was reported to be greater in Montreal than (28,5 5:6,8 In 1969, Katz et al. ~ reported that the maximum blockade attained after a single dose of d-tubocurarine or sueeinylcholine was greater and the duration of action was longer in New York than in London. The study was performed before dose-response techniques became common practice in the evaluation of muscle relaxants, and before a standard mode of stimulation, the train-of-four, 2 was introduced into clinical use and research.
L'intervalle entre l~njection et le bloc maximum dtait de (moyenne • ET) 3,9 5:1,3 min~ Paris et 4,5 + 1,3 min~ Montrdal (NS). La dur~e d'action, c'est-~-dire le temps entre l'injection de vEcuronium et la rdcupdration de 25%, dtait plus courte h ParisRecently, Fiset et al. 3 performed another transatlantic study, and compared the dose-response curves for vecuronium between Montl~al and Paris. In spite of similar demographic data in both centres and an identical anaesthetic and neuromuscular technique, the Paris doseresponse curve was shifted to the fight by 30%, that is, vecuronium was more potent in Montreal. The difference could not be explained by differences in age, sex, weight or body habitus, because these variables were similar in both cities. Disposition of the drug probably had little effect on these differences, because dose-response data are CAN J ANAESTH 1994 / 41: 10 / pp908-12
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