Effect of hypobaria on ventilatory and CO2 responses to short-term hypoxic exposure in cats.

Journal Article (Journal Article)

The effect of hypobaria on the ventilatory response to short-term hypoxia was studied by comparing the respiratory mechanical and inspired CO2 ventilatory responses to hypobaric hypoxia (438 mmHg) with normobaric hypoxia (11.8% FIO2). Fifteen spontaneously breathing, anesthetized cats were divided into three groups of five: time control, normobaric hypoxia and hypobaric hypoxia. Measurements of ventilation, gas exchange, and responses to intermittent CO2 rebreathing were collected over a 4 h period. PaO2 fell to 44.5 +/- 2.7 mmHg, PaCO2 fell to 24.8 +/- 0.9, and pH rose to 7.49 +/- 0.01 in both hypoxic groups. Tidal volume did not change with respect to time or condition, but frequency and ventilation were significantly increased in the hypobaric hypoxic group. The slope of the CO2 response was unchanged over time or by condition. These results suggest that hypobaric hypoxia may alter the pattern of breathing responses to hypoxia but not the CO2-response. If metabolic rate remained constant, these results could be explained by a difference in dead space between hypoxic conditions.

Full Text

Duke Authors

Cited Authors

  • Borel, CO; Guy, J; Barcik, U; Natoli, MJ; Vann, RD

Published Date

  • January 1998

Published In

Volume / Issue

  • 111 / 1

Start / End Page

  • 45 - 53

PubMed ID

  • 9496471

International Standard Serial Number (ISSN)

  • 0034-5687

Digital Object Identifier (DOI)

  • 10.1016/s0034-5687(97)00098-4


  • eng

Conference Location

  • Netherlands