Format

Send to

Choose Destination
J Clin Sleep Med. 2015 Jan 15;11(2):149-56. doi: 10.5664/jcsm.4462.

Night-to-night variability in obstructive sleep apnea severity: relationship to overnight rostral fluid shift.

Author information

1
Sleep Research Laboratory of the University Health Network Toronto Rehabilitation Institute, Toronto, Ontario, Canada: Centre for Sleep Medicine and Circadian Biology of the University of Toronto, Toronto, Ontario, Canada.
2
Sleep Research Laboratory of the University Health Network Toronto Rehabilitation Institute, Toronto, Ontario, Canada: Institute of Biomaterial and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
3
Sleep Research Laboratory of the University Health Network Toronto Rehabilitation Institute, Toronto, Ontario, Canada: Centre for Sleep Medicine and Circadian Biology of the University of Toronto, Toronto, Ontario, Canada: Department of Medicine of the University Health Network Toronto General Hospital, Toronto, Ontario, Canada.

Abstract

STUDY OBJECTIVES:

Overnight rostral fluid shift from the legs to the neck may narrow the pharynx and contribute to obstructive sleep apnea (OSA) pathogenesis. We hypothesized that night-to-night changes in the apnea-hypopnea index (AHI) would be associated with changes in overnight rostral fluid shift.

METHODS:

Twenty-six patients with OSA (AHI ≥10) underwent two polysomnograms 14 days apart with measurement of neck and leg fluid volumes (LFV), neck circumference and upper-airway cross-sectional area before and after sleep.

RESULTS:

Although mean AHI did not differ between polysomnograms, 35% of patients had a difference in AHI >10, indicating significant intra-individual variability. There were direct correlations between change in non-rapid-eye movement (NREM), but not REM AHI and change in evening LFV between polysomnograms (r = 0.440, p = 0.036 and r = 0.005, p = 0.982, respectively) and between change in supine, but not non-supine AHI and change in evening LFV (r = 0.483, p = 0.020 and r = 0.269, p = 0.280, respectively). An increase in evening LFV between polysomnograms was associated with a greater overnight decrease in LFV (r = 0.560, p = 0.005) and a greater overnight increase in neck fluid volume (r = 0.498, p = 0.016). Additionally, a greater overnight increase in neck circumference was associated with a greater overnight increase in neck fluid volume between polysomnograms (r = 0.453, p = 0.020) and a greater overnight decrease in upper-airway cross-sectional area (r = -0.587, p = 0.005).

CONCLUSION:

Intra-individual variability in OSA severity may be partly explained by day-to-day changes in evening leg fluid volume and overnight rostral fluid shift, which may be most important in the pathogenesis of OSA during NREM and supine sleep.

KEYWORDS:

Obstructive sleep apnea; rostral fluid shift; upper airway

PMID:
25406274
PMCID:
PMC4298772
DOI:
10.5664/jcsm.4462
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for American Academy of Sleep Medicine Icon for PubMed Central
Loading ...
Support Center