Association of sleep time in supine position with apnea-hypopnea index as evidenced by successive polysomnography
The purpose of this study is to evaluate the impact of body position during sleep on apnea-hypopnea index (AHI) and night-to-night variability in polysomnography (PSG) parameters.
Totally, 30 patients with obstructive sleep apnea syndrome (OSAS) were assessed prospectively with successive PSGs performed. The patients were categorized as increased (group A), decreased (group B), and unchanged (group C) AHI between the first and second PSG evaluations performed at least 1-week interval.
The mean AHI values were significantly higher in the second night (p = 0.02). A change in AHI was found in almost 85 % of the patients between two successive measurements. According to multivariate and correlation analyses and differences in total AHI in supine position (r = 0.897), it was found that the influence of the supine position was the primary factor contributing to the night-to-night variability. Supine AHI, non-supine AHI, and non-supine time findings did not add any significance on total AHI.
The variability observed in the AHI seems related to amount of sleeping time spent in supine position, suggesting that mean AHI alone is not that reliable in the accurate diagnosis of OSAS severity. A thorough evaluation of AHI in supine and non-supine positions is needed in order to understand better the severity of OSAS.
KeywordsSleep apnea Polysomnography Apnea-hypopnea index Sleep position Supin time
Compliance with ethical standards
No funding was received for this research.
Conflict of interest
All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria, educational grants, participation in speakers’ bureaus, membership, employment, consultancies, stock ownership, or other equity interest, and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.
All procedures performed in the studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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