Cerebrocortical oxygenation and ventilatory response during sustained hypoxia.


Journal Article

Cerebrocortical oxygenation was monitored in 8 healthy adults during exposure to sustained isocapnic hypoxia. Subjects were maintained at an arterial oxygen saturation (SaO2) of 80% for 12 min with a rebreathing circuit while cerebrocortical oxygenation was assessed non-invasively using near-infrared (NIR) spectroscopy to measure changes in the oxidation state of cytochrome a,a3 (Cyt a,a3) and changes in cortical blood volume (tBV). During sustained hypoxia, subjects demonstrated a biphasic ventilatory response. The mean minute ventilation (VE) peak response was 255% of baseline at an average of 3.4 +/- 0.5 min (mean +/- SE) after the initiation of hypoxia. A subsequent significant attenuation of VE to 163% (P less than 0.05) of baseline occurred after an additional 8.6 min. NIR monitoring revealed a significant (P less than 0.05) decrease in oxidized Cyt a,a3 as well as a significant (P less than 0.05) increase in tissue blood volume (tBV) at the time of peak VE. Both Cyt a,a3 and tBV remained stable during the remainder of the hypoxic period, despite attenuation of VE during sustained hypoxia. The data suggest that cerebrocortical oxygenation and blood flow remain constant when the ventilatory attenuation is observed during sustained hypoxia.

Full Text

Duke Authors

Cited Authors

  • Bacon, DS; Afifi, MS; Griebel, JA; Camporesi, EM

Published Date

  • May 1990

Published In

Volume / Issue

  • 80 / 2-3

Start / End Page

  • 245 - 257

PubMed ID

  • 2171123

Pubmed Central ID

  • 2171123

International Standard Serial Number (ISSN)

  • 0034-5687

Digital Object Identifier (DOI)

  • 10.1016/0034-5687(90)90087-f


  • eng

Conference Location

  • Netherlands