Cumulative brain desaturation: Time to consider brain derived parameters to measure daytime sleepiness in obstructive sleep apnea

Ramin Khatami; Ming Qi; Gordana Hügli; Zhongxing Zhang

doi:10.1016/j.sleep.2023.12.002

Cumulative brain desaturation: Time to consider brain derived parameters to measure daytime sleepiness in obstructive sleep apnea

Sleep Med. 2024 Jan:113:338-341. doi: 10.1016/j.sleep.2023.12.002. Epub 2023 Dec 6.

Authors

Ramin Khatami¹, Ming Qi², Gordana Hügli², Zhongxing Zhang³

Affiliations

¹ Center for Sleep Medicine, Sleep Research, and Epileptology, Clinic Barmelweid, Barmelweid, Switzerland; Barmelweid Academy, Clinic Barmelweid, Barmelweid, Switzerland; Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.
² Center for Sleep Medicine, Sleep Research, and Epileptology, Clinic Barmelweid, Barmelweid, Switzerland.
³ Center for Sleep Medicine, Sleep Research, and Epileptology, Clinic Barmelweid, Barmelweid, Switzerland; Barmelweid Academy, Clinic Barmelweid, Barmelweid, Switzerland. Electronic address: zhongxing.zhang@barmelweid.ch.

PMID: 38103465
DOI: 10.1016/j.sleep.2023.12.002

Abstract

Objective: /Background: The change in cerebral hemodynamics induced by sleep apneas and hypopneas may contribute to the daytime sleepiness in patients with obstructive sleep apnea (OSA). However, previous studies failed to discovery their relationship. We propose and test a new parameter, the cumulative brain oxygen desaturation, which may contribute to OSA patient's daytime sleepiness.

Patients/methods: 22 patients with severe OSA (apnea-hypopnea index (AHI) at diagnosis [mean ± standard deviation, std.]: 52.1 ± 21.6/h, median: 45.1/h, interquartile range: 34.4-60.2/h) were monitored by polysomnography during routine continuous positive airway pressure titration. The reductions of brain tissue oxygen saturation (StO2) in all respiratory events at baseline sleep were measured by frequency-domain near-infrared spectroscopy (NIRS). The cumulative brain desaturation was calculated as AHI times the mean StO2 desaturation (i.e., AHI×ΔStO2‾). Similarly, cumulative peripheral desaturation was also calculated, i.e., AHI×ΔSpO2‾ where ΔSpO2‾ was the mean reduction of peripheral arterial oxygen saturation (SpO2). The correlations between Epworth sleepiness scale (ESS) and AHI, ΔStO2‾, AHI×ΔStO2‾, and AHI×ΔSpO2‾ were tested, respectively. Linear regression was applied to predict ESS using AHI×ΔStO2‾ and AHI×ΔSpO2‾, with age and BMI as covariates.

Results: ESS significantly correlates to the cumulative brain desaturation (Pearson's correlation coefficient: 0.68, p = 0.00056), not the other parameters. Regression analysis only finds significant association between ESS and the cumulative cerebral desaturation (p = 0.00195) but not the cumulative peripheral desaturation (p = 0.71).

Conclusions: The cumulative brain oxygen desaturation, which comprehensively combines total sleep time, the frequency of apnea and hypopnea events, and the severity of cerebral oxygen desaturation, is a new indicator for daytime sleepiness in severe OSA.

Keywords: Brain; Cerebral oxygen desaturation; Cumulative oxygen desaturation; Near-infrared spectroscopy; Obstructive sleep apnea; Sleepiness.

MeSH terms

Brain
Disorders of Excessive Somnolence* / diagnosis
Disorders of Excessive Somnolence* / etiology
Humans
Oxygen
Sleep Apnea Syndromes*
Sleep Apnea, Obstructive* / diagnosis

Substances

Oxygen