Nocturnal episodic hypoxia and chemoreflex responsiveness.
Published: 2006
Language: eng
Number of pages: 74
ISBN-13: 9780494213667
Description: Chemoreflex responsiveness in obstructive sleep apnoea (OSA) is enhanced when evening vs. morning responses are compared. Such changes result in a decrease in ventilatory stability during sleep. I hypothesised that changes in chemoreflex responsiveness are due to the repetitive bouts of hypoxia experienced by OSA patients. To test this, I gave repetitive bouts of hypoxia to normal healthy subjects during overnight sleep experiments. Subjects slept in the lab for two nights, randomly assigned as a control or experimental night, on consecutive weeks. To assess if evening to morning changes occurred in chemoreflex responsiveness subjects performed two modified rebreathing tests, before sleep and immediately after waking. My results showed that a decrease in threshold of the central chemoreflex response on a night without hypoxia indicates an overnight stabilization of ventilation in a healthy subject. However, when healthy subjects are exposed to nocturnal episodic hypoxia this stabilizing decrease in the central chemoreflex response threshold was no longer evident and a destabilizing increase in peripheral chemoreflex sensitivity appeared. Therefore, I suggest that mimicking the repetitive bouts of hypoxia in OSA to normal healthy subjects, causes a destabilization of ventilation much like that reported in OSA.
Notes: Source: Masters Abstracts International, Volume: 45-03, page: 1400.

Thesis (M.Sc.)--University of Toronto, 2006.

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