Night-to-Night Variability in Sleep Disordered Breathing and the Utility of Esophageal Pressure Monitoring in Suspected Obstructive Sleep Apnea

Study on OSA screening and influencing factors in community-based elderly hypertensive patients based on single-lead wearable ECG devices

PURPOSE

Assessing whether single-lead ECG can be effectively and relatively inexpensively used in large-scale OSA screening, and identifying factors influencing moderate-to-severe OSA among elderly hypertensive patients without atypical symptoms in primary care.

METHODS

The study gathered data from 15 medical institutions in Ningxia between January and December 2022 using cloud platforms. The dataset included basic information and 72-h ECG monitoring for 2573 hypertensive patients over 65. OSA screening was conducted using the single-lead wearable ECG devices based on the ACAT algorithm. A multivariable logistic regression identified the main factors affecting OSA severity in these patients, and the AUC was used to assess the model's predictive accuracy.

RESULTS

The study found an OSA detection rate of 87.10%, with 55.42% being moderate to severe cases. Key risk factors associated with developing moderate-to-severe OSA included cardiac irregularities like supraventricular extrasystole and atrioventricular block, male gender, lifestyle factors like alcohol consumption and smoking, and health indicators such as SDNN ≤ 100 ms, abnormal LF/HF ratio, BMI, and age. The model's accuracy for predicting OSA, indicated by a ROAUC of 0.625, was moderate. Factors like gender, tea consumption, stroke history, and ventricular tachycardia were also independently linked to OSA severity.

CONCLUSION

This study combines single-lead wearable ECG devices with the ACAT algorithm for OSA screening in Ningxia, China. Initial screening identified 87.10% of participants as having OSA, with 55.42% being moderate to severe cases. This suggests a convenient, low-cost, and repeatable ECG-based method for OSA screening, potentially improving early detection and management of OSA by identifying potential risk factors.

Guidelines for the assessment and management of residual sleepiness in obstructive apnea-hypopnea syndrome: Endorsed by the French Sleep Research and Medicine Society (SFRMS) and the French Speaking Society of Respiratory Diseases (SPLF)

Excessive daytime sleepiness (EDS) is frequent among patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and can persist despite the optimal correction of respiratory events (apnea, hypopnea and respiratory efforts), using continuous positive airway pressure (CPAP) or mandibular advancement device. Symptoms like apathy and fatigue may be mistaken for EDS. In addition, EDS has multi-factorial origin, which makes its evaluation complex. The marketing authorization [Autorisation de Mise sur le Marché (AMM)] for two wake-promoting agents (solriamfetol and pitolisant) raises several practical issues for clinicians. This consensus paper presents recommendations of good clinical practice to identify and evaluate EDS in this context, and to manage and follow-up the patients. It was conducted under the mandate of the French Societies for sleep medicine and for pneumology [Société Française de Recherche et de Médecine du Sommeil (SFRMS) and Société de Pneumologie de Langue Française (SPLF)]. A management algorithm is suggested, as well as a list of conditions during which the patient should be referred to a sleep center or a sleep specialist. The benefit/risk balance of a wake-promoting drug in residual EDS in OSAHS patients must be regularly reevaluated, especially in elderly patients with increased cardiovascular and psychiatric disorders risks. This consensus is based on the scientific knowledge at the time of the publication and may be revised according to their evolution.

The prevalence of obstructive sleep apnea in Japanese asthma patients

BACKGROUND

Obstructive sleep apnea (OSA) occurs more commonly in asthma patients than in the general population because these conditions share some comorbidities. In Japan, the prevalence of OSA in the general population is reported to be approximately 20%; however, few reports have described the prevalence of OSA in asthma patients. Furthermore, the characteristics of Japanese patients with OSA and asthma are not clear.

METHODS

Adult asthma patients were recruited from the outpatient departments of our institution between August 31, 2017, and March 31, 2019. In all included patients, the presence and severity of OSA were evaluated by the Epworth Sleepiness Scale (ESS) and a home sleep test (HST) using portable polysomnography (PSG). The rate of coexisting OSA in asthma patients and the characteristics of those patients according to the severity of OSA were investigated.

RESULTS

Fifty-three patients were included. OSA was detected in 36 (67.9%) patients (mild, n = 15; moderate, n = 14; and severe, n = 7). Patients with OSA had significantly higher body mass index, Brinkman index, apnea-hypopnea index (AHI), and 3% oxygen desaturation index (ODI) values in comparison to those without OSA, while the percentage of the predicted value of forced vital capacity (%FVC) and lowest SpO2 levels were significantly lower. As the severity of OSA increased, age, brain natriuretic peptide level, AHI, and 3%ODI increased, and in contrast, FVC, %FVC, forced expiratory volume in one second (FEV1), percentage of the predicted value of FEV1 (%FEV1), Epworth Sleepiness Scale (ESS), 3%ODI, and lowest SpO2 levels decreased. In particular, the fact that the ESS value was inversely correlated with the severity of OSA in our patients was different from the general characteristics of OSA. Moreover, the AHI value was negatively correlated with FVC, %FVC, FEV1, and %FEV1. BMI was the only independent factor for the presence of OSA, and for asthma severity (FEV1, % of predicted), there was a weak correlation with smoking history.

CONCLUSIONS

This is the first report to investigate the prevalence of OSA in Japanese asthma patients, using an HST. This study suggests that an HST should be performed in addition to the sleep interview for asthma patients with refractory disease, a low pulmonary function, advanced age, and high BMI because the more severe the OSA, the lower the ESS value may be.

Multi-night measurement for diagnosis and simplified monitoring of obstructive sleep apnoea

Substantial night-to-night variability in obstructive sleep apnoea (OSA) severity has raised misdiagnosis and misdirected treatment concerns with the current prevailing single-night diagnostic approach. In-home, multi-night sleep monitoring technology may provide a feasible complimentary diagnostic pathway to improve both the speed and accuracy of OSA diagnosis and monitor treatment efficacy. This review describes the latest evidence on night-to-night variability in OSA severity, and its impact on OSA diagnostic misclassification. Emerging evidence for the potential impact of night-to-night variability in OSA severity to influence important health risk outcomes associated with OSA is considered. This review also characterises emerging diagnostic applications of wearable and non-wearable technologies that may provide an alternative, or complimentary, approach to traditional OSA diagnostic pathways. The required evidence to translate these devices into clinical care is also discussed. Appropriately sized randomised controlled trials are needed to determine the most appropriate and effective technologies for OSA diagnosis, as well as the optimal number of nights needed for accurate diagnosis and management. Potential risks versus benefits, patient perspectives, and cost-effectiveness of these novel approaches should be carefully considered in future trials.

Multi-night Prevalence, Variability, and Diagnostic Misclassification of Obstructive Sleep Apnea

Rationale Recent studies suggest that obstructive sleep apnea (OSA) severity can vary markedly from night to night which may have important implications for diagnosis and management. Objectives This study aimed to assess OSA prevalence from multi-night in-home recordings and the impact of night-to-night variability in OSA severity on diagnostic classification in a large, global, non-randomly selected community sample from a consumer database of people that purchased a novel, validated, under-mattress sleep analyzer. Methods 67,278 individuals aged between 18 and 90 years underwent in-home nightly monitoring over an average of ~170 nights per participant between July 2020 to March 2021. OSA was defined as a nightly mean apnea-hypopnea index (AHI) >15 events/h. Outcomes were multi-night global prevalence and likelihood of OSA misclassification from a single night AHI value. Measurements and Main Results Over 11.6 million nights of data were collected and analyzed. OSA global prevalence was 22.6% (95% CI: 20.9-24.3%). The likelihood of misdiagnosis in people with OSA based on a single night ranged between ~20% and 50%. Misdiagnosis error rates decreased with increased monitoring nights (e.g. 1-night F1-score=0.77 vs. 0.94 for 14-nights); and remained stable after 14-nights of monitoring. Conclusions Multi-night in-home monitoring using novel non-invasive under mattress sensor technology indicates a global prevalence of moderate to severe OSA of ~20%, and that ~20% of people diagnosed with a single night study may be misclassified. These findings highlight the need to consider night-to-night variation on OSA diagnosis and management. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

A Novel Model to Estimate Key Obstructive Sleep Apnea Endotypes from Standard Polysomnography and Clinical Data and Their Contribution to Obstructive Sleep Apnea Severity

Rationale: There are at least four key pathophysiological endotypes that contribute to obstructive sleep apnea (OSA) pathophysiology. These include 1) upper-airway collapsibility (Pcrit); 2) arousal threshold; 3) loop gain; and 4) pharyngeal muscle responsiveness. However, an easily interpretable model to examine the different ways and the extent to which these OSA endotypes contribute to conventional polysomnography-defined OSA severity (i.e., the apnea-hypopnea index) has not been investigated. In addition, clinically deployable approaches to estimate OSA endotypes to advance knowledge on OSA pathogenesis and targeted therapy at scale are not currently available.Objectives: Develop an interpretable data-driven model to 1) determine the different ways and the extent to which the four key OSA endotypes contribute to polysomnography-defined OSA severity and 2) gain insight into how standard polysomnographic and clinical variables contribute to OSA endotypes and whether they can be used to predict OSA endotypes.Methods: Age, body mass index, and eight polysomnography parameters from a standard diagnostic study were collected. OSA endotypes were also quantified in 52 participants (43 participants with OSA and nine control subjects) using gold-standard physiologic methodology on a separate night. Unsupervised multivariate principal component analyses and data-driven supervised machine learning (decision tree learner) were used to develop a predictive algorithm to address the study objectives.Results: Maximum predictive performance accuracy of the trained model to identify standard polysomnography-defined OSA severity levels (no OSA, mild to moderate, or severe) using the using the four OSA endotypes was approximately twice that of chance. Similarly, performance accuracy to predict OSA endotype categories ("good," "moderate," or "bad") from standard polysomnographic and clinical variables was approximately twice that of chance for Pcrit and slightly lower for arousal threshold.Conclusions: This novel approach provides new insights into the different ways in which OSA endotypes can contribute to polysomnography-defined OSA severity. Although further validation work is required, these findings also highlight the potential for routine sleep study and clinical data to estimate at least two of the key OSA endotypes using data-driven predictive analysis methodology as part of a clinical decision support system to inform scalable research studies to advance OSA pathophysiology and targeted therapy for OSA.

An efficient design for real-time obstructive sleep apnea OSA detection through esophageal pressure Pes signal

Obstructive Sleep Apnea (OSA) is a potentially common sleep disorder in which the upper airways are collapsed either partially or completely. The golden standard method for treating OSA, is the full night Continuous Positive Airway Pressure (CPAP). Yet, due to the ensuing discomfort, it incurs on patients, researchers have been motivated to investigate other alternatives, whereby, OSA can be effectively treated. Recently, an increasingly popular OSA treatment has been developed that consists in activating the protrusion muscles of the tongue by stimulating the Hypoglossal Nerve (HGN). In this context, the present work is conducted to propose the design of apnea detector module as part of an implantable HGN stimulator based on the esophageal Pressure Pes signal as a new approach for controlling OSA occurrence. Specifically, an effective real-time apnea event detecting algorithm is put forward. Following the achievement of satisfactory simulation results, attained through the Modelsim simulation tool, we proceeded with assessing the possibility of its hardware implementation on a Field-Programmable Gate Array (FPGA) device. To this end, the apnea detector module was synthesized and designed. The low power consumption and the small size, characterizing this module, which have made it possible to integrate it as part of a wirelessly-powered implantable HGN stimulator.

Diagnosing narcolepsy in the active duty military population

PURPOSE

Narcolepsy type I and type II are central hypersomnias characterized by excessive daytime sleepiness and nocturnal sleep disruptions. These rare disorders make the diagnosis complex, as multiple sleep disorders are known to cause false-positive results on testing. There is a high incidence of sleep disorders in the military, and the diagnosis of narcolepsy can have serious career implications. This study looked to assess for the presence of confounding disorders in patients previously diagnosed with narcolepsy.

METHODS

We conducted a retrospective analysis of patients aged 18-65 previously diagnosed with narcolepsy at an outside facility, referred for repeat evaluation at the Wilford Hall Sleep Disorders Center. Previous test results from the time of original diagnosis were reviewed if available and compared with repeat evaluation which included actigraphy, in-laboratory polysomnography, and multiple sleep latency testing.

RESULTS

Of the 23 patients, 2 (9%) retained a diagnosis of narcolepsy after repeat testing. Ten patients (43%) had insufficient sleep syndrome, five (22%) had significant circadian rhythm sleep-wake disorders, and nine (39%) patients were diagnosed with mild obstructive sleep apnea (OSA). Four of the nine patients with OSA (44%) had supine predominant OSA.

CONCLUSION

Diagnostic testing for narcolepsy may be influenced by the presence of comorbid sleep disorders including sleep-disordered breathing, insufficient sleep duration, and circadian misalignment which are common in active military personnel. This study emphasizes the importance of excluding these comorbid diagnoses in this population.

Sleep Studies Interpretation and Application

Obstructive sleep apnea is a common, but under-recognized, condition. Polysomnography remains the gold standard for diagnosing obstructive sleep apnea and determining whether treatment is appropriate. The development of home sleep apnea testing has allowed for a faster and more convenient method of diagnosis. Continuous positive airway pressure is the therapy of choice for most patients with obstructive sleep apnea, but otorhinolaryngologists can expect to see more and more patients looking for alternative treatments. This review highlights salient points relevant to sleep study application and interpretation for otorhinolaryngologists.

Long-term variability of the apnea-hypopnea index in a patient with mild to moderate obstructive sleep apnea

None

Night-to-night variability (NNV) of the degree of obstructive sleep apnea (OSA) over the long term is not well investigated. In our case, we investigated the NNV of the apnea-hypopnea index (AHI) with regard to sleep structure. Unattended polysomnography (PSG) at home was used to determine the AHI in the course of 4 weeks in a single patient with a mild-to-moderate OSA, by using the Somnocheck R&K system. The mean sleep period was 6.7 ± 1.1 hours and the mean AHI was 14.1 ± 5.7 events/h (range: 5.1-28.3 events/h; coefficient variability [CV] 40.4%). Independent of non-rapid eye movement and rapid eye movement (REM) sleep, the AHI in supine position (43.6 ± 16.9 events/h; CV 38.8%) was greater than during lateral-recumbent sleep (4.8 ± 4.1 events/h; CV 85.4%, P < .0001). A negative correlation was found for both: the AHI in supine position with the duration of supine position sleep (r = .59, P < .001), as well as the AHI in REM with the duration of REM sleep (r = -.37, P < .025). The AHI shows no rhythmicity neither from day to day nor from week to week. We found a high long-term NNV of the AHI, which was typically not influenced by the particular day of the week. Supine AHI is evidently dependent on the duration spent in that position throughout the night. We found it advisable to consider the existence of NNV in association with the degree of OSA, especially for patients with questionable therapeutic indication.

Quantitative assessment of nocturnal neural respiratory drive in children with and without obstructive sleep apnoea using surface EMG

NEW FINDINGS

What is the central question of this study? Recent studies have suggested potential utility of non-normalized respiratory muscle EMG as an index of neural respiratory drive (NRD). Whether NRD measured using non-normalized surface EMG of the lateral chest wall overlying the diaphragm (sEMGcw) recorded during nocturnal clinical polysomnography can differentiate children with and without obstructive sleep apnoea (OSA) is not known. What is the main finding and its importance? Non-normalized sEMGcw was increased in children with OSA and an additional group of snoring children without OSA but subjectively increased respiratory effort compared with primary snorers. The sEMGcw has potential clinical utility in evaluation of children with sleep-disordered breathing as an objective, non-invasive, non-volitional marker of NRD.

ABSTRACT

Our aim was to investigate whether neural respiratory drive measured by non-normalized surface EMG recorded from the chest wall overlying the diaphragm (sEMGcw) differentiates children with and without obstructive sleep apnoea (OSA). Polysomnography data of children aged 0-18 years were divided into the following three groups: (i) primary snorers (PS); (ii) snoring children without OSA but with increased work of breathing (incWOB; subjective physician report of increased respiratory effort during sleep); and (iii) children with OSA [obstructive apnoea-hypopnoea index (OAHI) >1 h^-1 ]. Excerpts of sEMGcw obtained during tidal unobstructed breathing from light, deep and rapid eye movement sleep were exported for quantitative analysis. Overnight polysomnography data from 45 PS [median age 4.4 years (interquartile range 3.0-7.7 years), OAHI 0 h^-1 (0.0-0.2 h^-1 )], 19 children with incWOB [age 2.8 years (2.4-5.7 years), OAHI 0.1 h^-1 (0.0-0.4 h^-1 )] and 27 children with OSA [age 3.6 years (2.6-6.2 years), OAHI 3.7 h^-1 (2.3-6.9 h^-1 )] were analysed. The sEMGcw was higher in those with OSA [8.47 μV (5.98-13.07 μV); P < 0.0001] and incWOB [8.97 μV (5.94-13.43 μV); P < 0.001] compared with PS [4.633 μV (2.98-6.76 μV)]. There was no significant difference in the sEMGcw between children with incWOB and OSA (P = 0.78). Log sEMGcw remained greater in children with OSA and incWOB compared with PS after age, body mass index centiles, sleep stages and sleep positions were included in the mixed linear models (P < 0.0001). The correlation between sEMGcw and OAHI in children without OSA was small (r_s  = 0.254, P = 0.04). The sEMGcw is increased in children with OSA and incWOB compared with PS.

Outcomes of Children with Mild Obstructive Sleep Apnea Treated Nonsurgically: A Retrospective Review

Objective

Obstructive sleep apnea (OSA) is characterized by partial or complete obstruction of the upper airway and is commonly caused by adenotonsillar hypertrophy in children. Accordingly, adenotonsillectomy is considered first-line treatment. However, in cases of mild OSA, nonsurgical management has been proposed as an alternative. The purpose of this study was to determine the outcomes of pediatric patients with mild obstructive sleep apnea (OSA) treated without surgical intervention.

Study Design

Case series with chart review.

Setting

Tertiary care university medical center.

Subjects and Methods

The medical records of children ages 2 to 18 years with OSA at Boston Medical Center from January 2000 to April 2017 were reviewed. Children with mild OSA (apnea- hypopnea index [AHI] between 1 and 5), who were managed nonsurgically and had serial polysomnograms, were included. Serial sleep studies were compared to assess for patterns of change.

Results

Of the 201 patients with mild OSA who were identified, 104 (52%) opted for initial nonsurgical management. Of those, 91 had a follow-up sleep study to reassess their OSA. Forty-two (46 %) had a greater than 20% decrease in AHI and 38 (41%) had a greater than 20% increase on the second sleep study. The remaining 11 had changes less than 20% in either direction. There was not a significant difference in the proportion of patients with an increase vs decrease in AHI on follow-up sleep study ( P > .05).

Conclusions

Mild pediatric OSA has approximately equal chances of worsening or improvement over time without surgical intervention, which is useful for counseling parents on treatment options.

High Adherence to CPAP Treatment Does Not Prevent the Continuation of Weight Gain among Severely Obese OSAS Patients

STUDY OBJECTIVES

Obstructive sleep apnea syndrome (OSAS) patients benefit from continuous positive airway pressure (CPAP) treatment in a dose-response manner. We determined adherence and weight control, as well as their predictors, among long-term CPAP users.

METHODS

Cohort of 1,023 OSAS patients had used CPAP on average of 6.6 ± 1.2 years. BMI was determined at baseline and at follow-up visits. There were 7.4 ± 1.7 BMI and 6.5 ± 1.8 CPAP usage measurements per patient on average. Using the Bayesian hierarchical model, we determined the patients' individual trends of BMI and adherence development. Patients with significantly increasing or decreasing trends were identified at the posterior probability level of > 90%.

RESULTS

The mean age in the cohort was 55.6 ± 9.8 years, BMI 33.5 ± 6.4 kg/m(2), apnea-hypopnea index 33.7 ± 23.1, and CPAP usage 6.0 ± 1.8 h/day. The majority of patients had no significant change in BMI (mean annual weight gain 0.04 ± 0.29 kg/m(2)) or CPAP adherence (mean annual increase 11.4 ± 7.0 min/day). However, at the individual level, 10% of the patients showed significant annual weight gain (0.63 ± 0.35 kg/m(2)) during the 5-year follow-up period. At baseline these patients were already more severely obese (mean BMI 40.0 ± 5.9 kg/m(2)) despite being younger (mean 50.9 ± 9.5 years) than the rest of the cohort.

CONCLUSIONS

In the majority of CPAP-treated OSAS patients, weight did not significantly change but gained slightly slower than in age-matched population in general. However, in 10% of patients, high adherence to CPAP treatment did not prevent the continuation of weight gain. These patients present a high-risk group for OSAS-related multimorbidity later in life.