Abstract
The ventilatory response to carbon dioxide is known tobe uninfluenced by changes in posture. To obtain similar data on the ventilatory response to hypoxia we studied seven subjects in each of two postures, lying and sitting, at a constant Pco2 midway between end-tidal and mixed venous. Minute ventilation was higher in the seated position than supine (p< 0.01) at this isocapnic level, attributable mainly to an increase in tidal volume (p< 0.05). However, there were no statistically significant differences in the ventilatory response, the tidal volume response, or the frequency response to hypoxia between the two postures.
Résumé
On sait déja que la réponse ventilatoire au gaz carbonique ne subit pas l’influence des changements de posture. Dans le but de comparer la relation entre les changements posturaux et la réponse à l’hypoxie, sept sujets ont été étudiés en position dorsale et assise à une Pco2 constante située à mi-chemin entre la Pco2 de fin d’expiration et celle du sang veineux mêlé. La ventilation-minute fut trouvée plus élevée en position assise qu’en position couchée (P < 0.01) à ce degré d’isocapnie et cette élévation est attribuable à une augmentation du volume courant (P< 0.05). Cependant, on n’a pas trouvé de différences significatives entre les deux postures lorsque furent étudiées la réponse ventilatoire, la réponse du volume courant et la réponse de la fréquence à l’hypoxie.
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Slutsky, A.S., Goldstein, R.G. & Rebuck, A.S. The effect of posture on the ventilatory response to hypoxia. Canad. Anaesth. Soc. J. 27, 445–448 (1980). https://doi.org/10.1007/BF03007041
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DOI: https://doi.org/10.1007/BF03007041