Abstract
To assess the effects of isoflurane on chemical regulation of ventilation, we studied the ventilatory responses to (1) hyperoxic hypercarbia, (2) isocapnic hypoxaemia, and (3) a single half vital capacity breath of carbon dioxide. 20 per cent in oxygen in 12 human subjects, awake and sedated or anaesthetized with isoflurane, 0.1 or 1.1 MAC. Sedation did not alter ventilation nor the ventilatory response to hypercarbia but reduced the responses to hypoxaemia and to the half vital capacity breath of CO2. Anaesthesia reduced ventilation and the response to hypercarbia and nearly abolished the responses to hypoxaemia and to the breath of CO2. The results indicate that isoflurane reduces ventilatory responses to several chemical drives and that it selectively impairs those responses mediated by peripheral chemoreceptors. In these respects, isoflurane is similar to halothane and enflurane.
Résumé
Afin d’étudier tes effets de l’isoflurane sur la régulation chimique de la ventilation nous avons étudié ta réponse venlilatoire à: I) l’hypercarbie hyperoxique; 2) l’hypoxémie isocapnique; 3) l’inspiration d’un mélange gazeux contenant 20 pour cent de CO2 dans l’oxygène. La quantité de ce mélange inhalé était équivalente à la moitié de la capacité vitale inspirée en une seule fois. Ce travail a été effectué chez 12 volontaires d’abord éveillés, ensuite sous sédation et enfin anesthésiés à l’isoflurane O.1 et 1.1 MAC.
La sedation à l’isofiurane n’a pas modifié la ventilation, non plus que la réponse ventilatoire à l’hypercarbie mais a réduit la réponse à l’hypoxémie et à l’inspiration de haute concentration de CO2 Pour sa part, l’anesthésie a réduit la ventilation et la réponse à Vhypercarbie et, à toutes fins utiles, a aboli la réponse à l’hypoxémie et à l’inspiration de CO2 Ce résultat indique que l’isofiurane diminue la réponse ventilatoire à plusieurs des stimulants chimiques el qu ’il prévient de façon sélective les réponses qui s’effectuent par les chémorécepteurs périphériques. En ceci, l’isoflurane est semblable à l’halothane et à l’enflurance.
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Supported by Medical Research Council (MRC) Grant #6443 and a grant from Ohio Medical Anesthetics.
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Knill, R.L., Kieraszewicz, H.T., Dodgson, B.G. et al. Chemical regulation of ventilation during isoflurane sedation and anaesthesia in humans. Can Anaesth Soc J 30, 607–614 (1983). https://doi.org/10.1007/BF03015231
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DOI: https://doi.org/10.1007/BF03015231