Effects of hyperventilation on conjunctival oxygen tension in humans

Critical Care Medicine
M NisamC J Fisher

Abstract

A polarographic conjunctival oxygen sensor was used to measure oxygen tension in a tissue bed supplied by the internal carotid artery. The shared vascular source of the conjunctiva and brain suggests that conjunctival PO2 monitoring may provide an index of cerebral perfusion. We studied the effects of hyperventilation, a known stimulus of cerebral vasoconstriction, on conjunctival oxygen tension (PcjO2) in six normal, healthy adults; arterial blood gases were simultaneously measured in four of these subjects. A 5-min period of hyperventilation to a PaCO2 near 20 torr resulted in a rapid and significant (p less than .01) increase in systemic oxygen tension as measured by arterial blood gases and a transcutaneous oxygen monitor. These values gradually returned to baseline upon cessation of hyperventilation. PcjO2, however, decreased significantly (p less than .01) during hyperventilation, suggesting vasoconstriction of the conjunctival vascular supply. Because these changes temporally correlate with the cerebral vasoconstriction during hyperventilation, the conjunctival index of tissue oxygen tension may correlate with cerebral perfusion.

Citations

May 1, 1994·International Journal of Clinical Monitoring and Computing·P SjöströmB Odlind
Jun 1, 1989·Archives of Emergency Medicine·J Heyworth
Aug 1, 1987·Annals of Emergency Medicine·W F RutherfordC J Fisher
Oct 1, 1989·Scandinavian Journal of Clinical and Laboratory Investigation·H H SteenfosP D Wimberley
May 18, 2019·Proceedings of the National Academy of Sciences of the United States of America·Shardulendra P Sherchand, Ashok Aiyar
Jul 15, 1988·Klinische Wochenschrift·U StaedtD L Heene

Related Concepts

Structure of Bulbar Conjunctiva
Hyperventilation
Dioxygen

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