Arousal threshold modifies the effect of CPAP on executive function among individuals with obstructive sleep apnea.

Unlabelled: Arousal Threshold Modifies the Effect of CPAP on Executive Function Among Individuals with Obstructive Sleep Apnea.

Background: Obstructive Sleep Apnea (OSA) is associated with neurocognitive dysfunction. However, randomized trials evaluating the effects of continuous positive airway pressure (CPAP) on neurocognition in those without dementia do not show a benefit.

Combination Drug Therapy with Acetazolamide, Eszopiclone +/- Venlafaxine for Obstructive Sleep Apnea (RESCUE-Combo): A Randomized, Double-blind, Placebo-controlled Trial.

Introduction: Acetazolamide, eszopiclone, and venlafaxine may target different underlying mechanisms of obstructive sleep apnea (OSA) and individually may partially improve OSA severity in select patients. We tested whether acetazolamide+eszopiclone (DualRx) improves OSA severity. We further explored whether addition of venlafaxine (TripleRx) improves OSA in patients who do not fully respond to DualRx.

Pathogenesis of sleep-disordered breathing in the setting of opioid use: a multiple mediation analysis using physiology.

Study Objectives: Opioid medications are commonly used and are known to impact both breathing and sleep and are linked with adverse health outcomes including death. Clinical data indicate that chronic opioid use causes central sleep apnea, and might also worsen obstructive sleep apnea. The mechanisms by which opioids influence sleep-disordered breathing (SDB) pathogenesis are not established.

Adverse pregnancy outcomes and pharyngeal flow limitation during sleep: Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-be (nuMoM2b).

Background: Pharyngeal flow limitation during pregnancy may be a risk factor for adverse pregnancy outcomes but was previously challenging to quantify. Our objective was to determine whether a novel objective measure of flow limitation identifies an increased risk of pre-eclampsia (primary outcome) and other adverse outcomes in a prospective cohort: Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-be (nuMoM2b).

Methods: Flow limitation severity scores (0%=fully obstructed, 100%=open airway), quantified from breath-by-breath airflow shape, were obtained from home sleep tests during early (6-15 weeks) and mid (22-31 weeks) pregnancy.

Loop Gain as a Predictor of Blood Pressure Response in Patients Treated for Obstructive Sleep Apnea: Secondary Analysis of a Clinical Trial.

Randomized trials have shown inconsistent cardiovascular benefits from obstructive sleep apnea (OSA) therapy. Intermittent hypoxemia can increase both sympathetic nerve activity and loop gain ("ventilatory instability"), which may thus herald cardiovascular treatment benefit. To test the hypothesis that loop gain predicts changes in 24-hour mean blood pressure (MBP) in response to OSA therapy and compare its predictive value against that of other novel biomarkers.

Respiratory Event-Induced Blood Pressure Oscillations Vary by Sleep Stage in Sleep Apnea Patients.

Obstructive sleep apnea (OSA) pathologically stresses the cardiovascular system. Apneic events cause significant oscillatory surges in nocturnal blood pressure (BP). Trajectories of these surges vary widely.

Pathophysiology Underlying Demographic and Obesity Determinants of Sleep Apnea Severity.

Sleep apnea is the manifestation of key endotypic traits, including greater pharyngeal collapsibility, reduced dilator muscle compensation, and elevated chemoreflex loop gain. We investigated how endotypic traits vary with obesity, age, sex, and race/ethnicity to influence sleep apnea disease severity (apnea-hypopnea index [AHI]). Endotypic traits were estimated from polysomnography in a diverse community-based cohort study (Multi-Ethnic Study of Atherosclerosis,  = 1,971; age range, 54-93 yr).

Within-night repeatability and long-term consistency of sleep apnea endotypes: the Multi-Ethnic Study of Atherosclerosis and Osteoporotic Fractures in Men Study.

Study Objectives: Obstructive sleep apnea (OSA) is characterized by multiple "endotypic traits," including pharyngeal collapsibility, muscle compensation, loop gain, and arousal threshold. Here, we examined (1) within-night repeatability, (2) long-term consistency, and (3) influences of body position and sleep state, of endotypic traits estimated from in-home polysomnography in mild-to-severe OSA (apnea-hypopnea index, AHI > 5 events/h).

Methods: Within-night repeatability was assessed using Multi-Ethnic Study of Atherosclerosis (MESA): Traits derived separately from "odd" and "even" 30-min periods were correlated and regression (error vs.

The Sleep Apnea-Specific Pulse-Rate Response Predicts Cardiovascular Morbidity and Mortality.

Randomized controlled trials have been unable to detect a cardiovascular benefit of continuous positive airway pressure in unselected patients with obstructive sleep apnea (OSA). We hypothesize that deleterious cardiovascular outcomes are concentrated in a subgroup of patients with a heightened pulse-rate response to apneas and hypopneas (ΔHR). We measured the ΔHR in the MESA (Multi-Ethnic Study of Atherosclerosis) ( = 1,395) and the SHHS (Sleep Heart Health Study) ( = 4,575).

Prolonged Circulation Time Is Associated With Mortality Among Older Men With Sleep-Disordered Breathing.

Background: Conventional metrics to evaluate sleep-disordered breathing (SDB) have many limitations, including their inability to identify subclinical markers of cardiovascular (CV) dysfunction.

Research Question: Does sleep study-derived circulation time (Ct) predict mortality, independent of CV risks and SDB severity?

Study Design And Methods: We derived average lung to finger Ct (LFCt) from sleep studies in older men enrolled in the multicenter Osteoporotic Fractures in Men (MrOS) Sleep study. LFCt was defined as the average time between end of scored respiratory events and nadir oxygen desaturations associated with those events.

Quantification of Nocturnal Blood Pressure Oscillations Induced by Sleep Disordered Breathing.

We present an approach to quantifying nocturnal blood pressure (BP) variations that are elicited by sleep disordered breathing (SDB). A sample-by-sample aggregation of the dynamic BP variations during normal breathing and BP oscillations prompted by apnea episodes is performed. This approach facilitates visualization and analysis of BP oscillations.

Dynamic Estimation of Cerebral Blood Flow Using Photoplethysmography Signal during Simulated Apnea.

Monitoring apnea-induced cerebral blood flow oscillations is of importance for assessing apnea patient brain health. Using an autoregressive moving average model, peak and trough values of cerebral blood flow were estimated from a concurrently recorded forehead photoplethysmography signal. Preliminary testing of the method in 7 subjects (4 F, 32±4 yrs.

Dynamic Estimation of Cerebral Blood Flow Using Blood Pressure Signal in sleep Apnea Patients.

Monitoring apnea-induced cerebral blood flow (CBF) oscillations is of importance for assessing apnea patient brain health. Blood pressure (BP) oscillations during apnea can induce oscillations in CBF. Preliminary results of testing an Auto Regressive Moving Average model relating nocturnal CBP oscillations to nocturnal BP variations in 8 obstructive sleep apnea subjects (3 F, 55±8 yrs.

Estimation of cerebral blood flow velocity during breath-hold challenge using artificial neural networks.

Unlabelled: The effect of untreated Obstructive Sleep Apnoea (OSA) on cerebral haemodynamics and CA impairment is an active field of research interest. A breath-hold challenge is usually used in clinical and research settings to simulate cardiovascular and cerebrovascular changes that mimic OSA events. This work utilises temporal arterial oxygen saturation (SpO) and photoplethysmography (PPG) signals to estimate the temporal cerebral blood flow velocity (CBFv) waveform.

Increased Oxidative Stress, Loop Gain And The Arousal Threshold Are Clinical Predictors Of Increased Apnea Severity Following Exposure To Intermittent Hypoxia.

Purpose: We determined if oxidative stress prior to sleep onset is correlated to loop gain (LG) and the arousal threshold (AT) during non-rapid eye movement (NREM) sleep. We also explored if LG and AT are correlated with apnea severity and indices of upper airway collapsibility during NREM sleep.

Methods: Thirteen male participants with obstructive sleep apnea (apnea-hypopnea index > 5 events/hr) were administered an antioxidant or placebo cocktail while exposed to mild intermittent hypoxia in the awake state.

Exposure to mild intermittent hypoxia increases loop gain and the arousal threshold in participants with obstructive sleep apnoea.

Key Points: Repeated daily mild intermittent hypoxia has been endorsed as a therapy to promote the recovery of respiratory and limb motor dysfunction. One possible side-effect of this therapy is an increase in apnoeic event number and duration, which is particularly relevant to participants with motor disorders coupled with an increased incidence of sleep apnoea. In this study, we report that increases in apnoeic event number and duration, following exposure to daily intermittent hypoxia, are the result of an increase in respiratory loop gain and the arousal threshold, in participants with obstructive sleep apnoea.

Mathematical Modeling of Arterial Blood Pressure Using Photo- Plethysmography Signal in Breath-hold Maneuver.

recent research has shown that each apnea episode results in a significant rise of the beat-to-beat blood pressure followed by a drop to the pre-episode levels when patient resumes normal breathing. While the physiological implications of these repetitive and significant oscillations are still unknown, it is of interest to quantify them. Since current array of instruments deployed for polysomnography studies does not include beat-to-beat measurement of blood pressure, but includes oximetry which can supply pulsatile photoplethysmography (PPG) signal, in addition to percent oxygen saturation.