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A Model to Simulate Clinically Relevant Hypoxia in Humans
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Impact of Hypoxemia Severity on Cardiac Autonomic Regulation in Children With Sleep-Disordered Breathing: A McGill

Gintare Oboleviciene1, Ausra Snipaitiene1, Valdone Miseviciene1

  • 1Paediatric Department, Lithuanian University of Health Sciences, Medical Academy, Kaunas, Lithuania.

Journal of Sleep Research
|July 28, 2026
PubMed

Insights

Nocturnal hypoxia in children with sleep-related breathing disorders (SRBD) significantly impacts cardiac autonomic function. Higher hypoxemia severity, measured by the McGill Oximetry Score (MOS), correlates with reduced parasympathetic activity and autonomic imbalance.

Area of Science:

  • Pediatric Sleep Medicine
  • Cardiovascular Physiology
  • Autonomic Nervous System Regulation

Background:

  • Sleep-related breathing disorders (SRBD) are a major pediatric health issue.
  • Traditional polysomnography indices may not fully reflect the cardiac impact of pediatric SRBD.
  • Nocturnal hypoxemia's effect on cardiac autonomic regulation requires further characterization.

Purpose of the Study:

  • To evaluate the impact of intermittent nocturnal hypoxia on cardiac autonomic function in children with suspected SRBD.
  • To examine the association between hypoxemia severity (McGill Oximetry Score - MOS) and heart rate variability (HRV) indices.

Main Methods:

  • Included 127 children (aged 2-17 years) undergoing polysomnography.
  • Categorized participants into four groups based on MOS (1-4).
  • Analyzed whole-night and sleep-stage-specific HRV indices in relation to MOS.

Main Results:

  • Significantly lower parasympathetic HRV indices observed in MOS 3 and MOS 4 groups.
  • High-frequency power decreased, and LF/HF ratio increased progressively with higher MOS.
  • Trends indicated reduced parasympathetic modulation and altered autonomic balance with increasing hypoxemia severity.

Conclusions:

  • Intermittent nocturnal hypoxia, quantified by MOS, is closely linked to cardiac autonomic imbalance in pediatric SRBD.
  • Higher MOS values are associated with diminished parasympathetic modulation and disrupted autonomic balance.
  • Hypoxemia-based metrics like MOS are clinically relevant for assessing autonomic dysfunction risk in children with SRBD.

Keywords:
McGill oximetry scorecardiac autonomic regulationheart rate variabilityintermittent nocturnal hypoxiasleep‐related breathing disorders

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