Abstract
Purpose
This prospective, randomized, double-blind study was performed to determine the effect of administration of physostigmine on the dose of propofol required to produce loss of consciousness.
Methods
Forty female unpremedicated patients were assigned in a random blind design to receive either 2 mg physostigmine or equal volume of normal salineiv, five minutes before induction of anaesthesia with propofol. All patients received general anaesthesia for breast surgery. Propofol was infused at a constant rate of 200 ml · hr−1 while patients were breathing oxygen 100% via a face mask. In each patient the dose of propofol required to produce loss of the ability to grasp a 20 ml synnge was recorded as the end-point of loss of consciousness. At this point the protocol was terminated and, after intubation of the trachea, anaesthesia was maintained with a nitrous oxide-isoflurane or sevoflurane mixture in oxygen, increments of an opioid and a muscle relaxant. Doses of anaesthetic drugs and duration of anaesthesia vaned and depended on the type of breast surgery, determined by frozen section.
Results
The mean ± SD dose of propofol required to produce loss of consciousness was 2.4 ± 0.6 mg · kg−1 and 2.0 ± 0.4 mg · kg−1 in the physostigmine and in the normal saline groups respectively (P = 0.014).
Conclusion
Physostigmine pretreatment increases the dose of propofol required to produce loss of consciousness.
Résumé
Objectif
Cette étude prospective, aléatoire et en double insu visait à déterminer l’influence de l’administration de la physostigmine sur la dose de propofol requise pour provoquer la perte de conscience.
Méthodes
Cette étude aléatoire et à l’insu regroupait quarante femmes non prémédiquées et programmées pour une chirurgie du sein sous anesthésie générale. Elles ont reçu soit 2 mg de physostigmine sort un volume égal de sol. phys. iv cinq minutes avant l’administration du propofol. Une perfusion de propofol de 200 ml · h−1 était mise en marche à débit constant alors que les patientes respiraient de l’oxygène à 100% par masque facial. On enregistrait chez chacune des patientes la dose de propofol requise pour produire la perte de la capacité de préhension d’une seringue de 20 ml. méthode adoptée comme cntère de la perte de conscience. À ce moment, le protocole prenait fin et, après l’intubation de la trachée, l’anesthésie était maintenue avec un mélange de protoxyde d’azote et d’isoflurane ou de sévoflurane en oxygène associé à des doses répétées de morphiniques et de relaxants musculaires. Les doses d’agents anesthésiques et la durée de l’anesthésie vanaient et dépendaient de la chirurgie mammaire déterminée par la coupe en congélation.
Résultats
La dose moyenne (± ÉT) de propofol requise pour faire perdre conscience était de 2,4 ± 0,6 mg · kg−1 pour le groupe physostigmine et de 2.0 ± 0.4 mg · kg−1 pour le groupe contrôle (P = 0.014).
Conclusion
Le prétraitement à la physostigmine augmente la dose de propofol requise pour provoquer la perte de conscience.
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Fassoulaki, A., Sarantopoulos, C. & Derveniotis, C. Physostigmine increases the dose of propofol required to induce anaesthesia. Can J Anesth 44, 1148–1151 (1997). https://doi.org/10.1007/BF03013335
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DOI: https://doi.org/10.1007/BF03013335