Night-to-Night Variability of Polysomnography-Derived Physiologic Endotypic Traits in Patients With Moderate to Severe OSA.

Background: Emerging data suggest that determination of physiologic endotypic traits (eg, loop gain) may enable precision medicine in OSA.

Research Question: Does a single-night assessment of polysomnography-derived endotypic traits provide reliable estimates in moderate to severe OSA?

Study Design And Methods: Two consecutive in-lab polysomnography tests from a clinical trial (n = 67; male, 69%; mean ± SD age, 61 ± 10 years; apnea-hypopnea index [AHI] 53 ± 22 events/h) were used for the reliability analysis. Endotypic traits, reflecting upper airway collapsibility (ventilation at eupneic drive [V]), upper airway dilator muscle tone (ventilation at the arousal threshold [V]), loop gain (stability of ventilatory control, LG1), and arousal threshold (ArTh) were determined.

Overnight pulse wave analysis to assess autonomic changes during sleep in insomnia patients and healthy sleepers.

Insomnia has been associated with increased cardiovascular (CV) risk, which may be linked to sympathetic activation. Non-invasive overnight pulse wave analysis may be a useful tool to detect early signs of autonomic changes during sleep in insomniacs. Fifty-two participants (26 men, 37±13 years, BMI: 24±5 kg/m2, 26 insomniacs/ 26 controls) underwent overnight polysomnography with pulse oximetry and pulse wave analysis including pulse rate, vascular stiffness (pulse propagation time, PPT), and a composite cardiac risk index based on autonomic function and overnight hypoxia.