Inspiratory-to-expiratory time ratio and alveolar ventilation during high-frequency ventilation in dogs

Y. Yamada, C. A. Hales, J. G. Venegas

研究成果: Article査読

8 被引用数 (Scopus)

抄録

It has been suggested that the increase in inspiratory flow rate caused by a decrease in the inspiratory-to-expiratory time ratio (I:E) at a constant tidal volume (VT) could increase the efficiency of ventilation in high-frequency ventilation (HFV). To test this hypothesis, we studied the effect of changing I:E from 1:1 to 1:4 on steady-state alveolar ventilation (VA) at a given VT and frequency (f) and at a constant mean lung volume (VL). In nine anesthetized, paralyzed, supine dogs, HFV was performed at 3, 6, and 9 Hz with a ventilator that delivered constant inspiratory and expiratory flow rates. Mean airway pressure was adjusted so that VL was maintained at a level equivalent to that of resting FRC. At each f and one of the I:E chosen at random, VT was adjusted to obtain a eucapnic steady state [arterial pressure of CO2 (Pa(CO2)) = 37 ± 3 Torr]. After 10 min of each HFV, Pa(CO2), arterial pressure of O2 (Pa(O2)), and CO2 production (V̇CO2) were measured, and I:E was changed before repeating the run with the same f and VT. V̇A was calculated from the ratio of V̇CO2 and Pa(CO2). We found that the change of I:E from 1:1 to 1:4 had no significant effects on Pa(CO2), Pa(O2), and V̇A at any of the frequencies studied. We conclude, therefore, that the mechanism or mechanisms responsible for gas transport during HFV must be insensitive to the changes in inspiratory and expiratory flow rates over the VT - f range covered in our experiments.

本文言語English
ページ(範囲)1903-1907
ページ数5
ジャーナルJournal of Applied Physiology
61
5
DOI
出版ステータスPublished - 1986
外部発表はい

ASJC Scopus subject areas

  • 生理学
  • 生理学(医学)

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