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Chronic intermittent hypoxia in obstructive sleep apnea: a narrative review from pathophysiological pathways to a precision clinical approach

Sleep and Breathing volume 24, pages 751–760 (2020)Cite this article

Abstract

Obstructive sleep apnea syndrome (OSAS) is a prevalent condition caused by dynamic upper airway collapse during sleep. The pathological impact and consequences are due to chronic intermittent hypoxia (CIH). Hypoxia increases the expression of several inflammatory stress markers and endothelial dysfunction. Recent studies suggest that patients with a similar AHI but with severe nocturnal hypoxia using oximetric parameters, such as the lowest saturation of oxygen during the night (min SaO2), percentage of total sleep time with oxygen saturation < 90% (T90) or the oxygen desaturation index (ODI-3%), commonly reported during the sleep study, are indicative of the increased expression of inflammatory markers due to severe nocturnal hypoxia and CIH during the night compared to subjects with moderate-severe OSAS without severe nocturnal hypoxia. The aim of this review is to describe physiological pathways involved in OSAS and their clinical consequences, focused in CIH and oximetric parameters showed in sleep study and their potential utility as inflammatory markers.

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Authors and Affiliations

  1. Facultad de Medicina, Universidad San Sebastian, Concepcion, Chile

    Gonzalo Labarca

  2. Department of Clinical Biochemistry and Immunology, Faculty of Pharmacy, University of Concepcion, Concepcion, Chile

    Gonzalo Labarca, Jorge Gower & Liliana Lamperti

  3. Centro de Enfermedades Respiratorias y grupo de estudio trastornos respiratorios del sueño (GETRS), Clínica Las Condes, Santiago, Chile

    Jorge Dreyse & Jorge Jorquera

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  1. Gonzalo Labarca
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  2. Jorge Gower
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  3. Liliana Lamperti
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  4. Jorge Dreyse
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Contributions

Dr. Labarca: principal investigator, data extraction, data analysis, manuscript editing, and final approval

Dr. Gower, Lamperti: data extraction, data synthesis, manuscript editing, and final approval

Dr. Dreyse, Jorquera: data conception, critical analysis, manuscript editing, and final approval

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Correspondence to Gonzalo Labarca.

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Comments

Obstructive sleep apnea (OSA) is associated with multiple comorbidities, specifically metabolic syndrome and thus remains a serious health issue. Significant clinical as well as basic research, and some review articles have described the pathways that lead to various pathophysiological manifestations

This article by Dr Labarca et al provides an interesting narrative review of these pathophysiological pathways, summarizes its clinical consequences in multiple organ systems, and its effects and association with inflammatory markers. It is unique as it narrows its focus on oximeteric parameters noted on the sleep study, and highlights the current literature that identifies this hypoxia or the hypoxic burden as an element of greater risk and worse prognosis, even in patients with same or similar AHI. It recognizes limitations of the current literature in being able to discern the perfect oximetric parameter that would identify the different "phenotypes" of OSA, that may be associated with worse clinical outcomes and thus calls for further research in this area.

Toshita Kumar Bristol, CT, USA

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Labarca, G., Gower, J., Lamperti, L. et al. Chronic intermittent hypoxia in obstructive sleep apnea: a narrative review from pathophysiological pathways to a precision clinical approach. Sleep Breath 24, 751–760 (2020). https://doi.org/10.1007/s11325-019-01967-4

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Keywords

  • Obstructive
  • Sleep Apnea
  • Hypoxia
  • Sleep apnea