Worsening of central sleep apnea at high altitude - A role for cerebrovascular function

Keith R. Burgess*, Samuel J E Lucas, Kelly Shepherd, Andrew Dawson, Marianne Swart, Kate N. Thomas, Rebekah A I Lucas, Joseph Donnelly, Karen C. Peebles, Rishi Basnyat, Philip N. Ainslie

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

Although periodic breathing during sleep at high altitude occurs almost universally, the likely mechanisms and independent effects of altitude and acclimatization have not been clearly reported. Data from 2005 demonstrated a significant relationship between decline in cerebral blood flow (CBF) at sleep onset and subsequent severity of central sleep apnea that night. We suspected that CBF would decline during partial acclimatization. We hypothesized therefore that reductions in CBF and its reactivity would worsen periodic breathing during sleep following partial acclimatization. Repeated measures of awake ventilatory and CBF responsiveness, arterial blood gases during wakefulness. and overnight polysomnography at sea level, upon arrival (days 2-4), and following partial acclimatization (days 12-15) to 5,050 m were made on 12 subjects. The apnea-hypopnea index (AHI) increased from to 77 ± 49 on days 2-4 to 116 ± 21 on days 12-15 (P = 0.01). The AHI upon initial arrival was associated with marked elevations in CBF (+28%, 68 ± 11 to 87 ± 17 cm/s; P < 0.05) and its reactivity to changes in PaCO2 [>90%, 2.0 ± 0.6 to 3.8 ± 1.5 cm·s -1·mmHg-1 hypercapnia and 1.9 ± 0.4 to 4.1 ± 0.9 cm·s-1·mmHg-1 for hypocapnia (P < 0.05)]. Over 10 days, the increases resolved and AHI worsened. During sleep at high altitude large oscillations in mean CBF velocity (CBFv) occurred, which were 35% higher initially (peak CBFv = 96 cm/s vs. peak CBFv = 71 cm/s) than at days 12-15. Our novel findings suggest that elevations in CBF and its reactivity to CO2 upon initial ascent to high altitude may provide a protective effect on the development of periodic breathing during sleep (likely via moderating changes in central PCO2).

Original languageEnglish
Pages (from-to)1021-1028
Number of pages8
JournalJournal of Applied Physiology
Volume114
Issue number8
DOIs
Publication statusPublished - 15 Apr 2013
Externally publishedYes

Fingerprint Dive into the research topics of 'Worsening of central sleep apnea at high altitude - A role for cerebrovascular function'. Together they form a unique fingerprint.

Cite this