Performance of peripheral arterial tonometry-based testing for the diagnosis of obstructive sleep apnea in a large sleep clinic cohort

Long-Term Adherence to Continuous Positive Airway Pressure in Patients with Obstructive Sleep Apnoea Set Up in a Complete Remote Pathway: A Single-Centre Service Evaluation Project

Background: Continuous positive airway pressure (CPAP) is the first-line treatment for obstructive sleep apnoea (OSA). Maintaining adherence to CPAP in the long term is a clinical problem, and numerous factors have been identified that impact adherence. Although fully remote diagnostic and CPAP services were frequently utilised during the COVID-19 pandemic for patients with OSA, long-term adherence data have not been published. The aim of this service evaluation project was to describe the long-term adherence to CPAP. We also analysed factors that are associated with it. Methods: two-hundred and eighty patients diagnosed with OSA and set up on CPAP remotely during the first wave of the COVID-19 pandemic as part of routine clinical practice were analysed. Results: One-hundred and seven patients (38%) were fully adherent to CPAP at 24 months, determined by at least 4 h of usage on at least 70% of the days. Of the factors analysed, body mass index, disease severity, driving status and the presence of depression were related to long-term adherence (all p < 0.05). Conclusions: with the likelihood of future pandemics similar to COVID-19, our data provide evidence that fully remote pathways for management of patients with OSA can be designed and be sustainable with good long-term adherence.

Worldwide prevalence and associated risk factors of obstructive sleep apnea: a meta-analysis and meta-regression

PURPOSE

This study aimed to identify the prevalence of obstructive sleep apnea (OSA) and associated risk factors globally.

METHODS

Six databases and registrations and three grey databases were explored for observational field research. Independently and impartially paired reviewers selected research, gathered data, and evaluated the methodological quality. Heterogeneity was investigated using subgroup analysis and meta-regression following the moderating variable in a meta-analysis of proportions with a random-effects model. The critical appraisal instrument developed by the Joanna Briggs Institute was used to evaluate the listed studies' methodology. The certainty of the evidence was evaluated using the GRADE tool.

RESULTS

A total of 8236 articles were collected during the database search, resulting in 99 articles included for qualitative synthesis, and 98 articles were included for the meta-analysis. The estimated combined prevalence of OSA was 54% [CI 95% = 46-62%; I2 = 100%]. Mean age, percentage of moderate-severe cases, and the sample's body mass index (BMI) did not affect the heterogeneity that was already present when meta-regressed (p > 0.05). Ninety-one studies were deemed to have a low risk of bias, while eight were deemed to have a moderate risk. For OSA prevalence outcomes, the GRADE criteria were considered very low.

CONCLUSION

Approximately half of the people worldwide have OSA. High BMI, increasing age, and male gender are described as risk factors in the literature, but these covariates do not affect pre-existing heterogeneity.

Perioperative management of Obstructive Sleep Apnoea: Present themes and future directions

PURPOSE OF REVIEW

Obstructive sleep apnoea (OSA) is an increasingly common pathology that all those involved in perioperative care will come across. Patients with the condition present a challenge at many stages along the perioperative journey, not least because many patients living with OSA are unaware of their diagnosis.Key interventions can be made pre, intra-, and postoperatively to improve outcomes. Knowledge of screening tools, diagnostic tests, and the raft of treatment options are important for anyone caring for these patients.

RECENT FINDINGS

Recent literature has highlighted the increasing complexity of surgical patients and significant underdiagnosis of OSA in this patient population. Work has demonstrated how and why patients with OSA are at a higher perioperative risk and that effective positive airways pressure (PAP) therapy can reduce these risks, alongside evidencing how best to optimise adherence to therapy, a key issue in OSA.

SUMMARY

OSA, and particularly undiagnosed OSA, presents a huge problem in the perioperative period. Perioperative PAP reduces the risk of postoperative complications but adherence remains an issue. Bespoke perioperative pathways should be developed to identify and optimise high risk patients, although at present evidence on how best to achieve this is lacking.

Smart sleep: what to consider when adopting AI-enabled solutions in clinical practice of sleep medicine

Since the publication of its 2020 position statement on artificial intelligence (AI) in sleep medicine by the American Academy of Sleep Medicine, there has been a tremendous expansion of AI-related software and hardware options for sleep clinicians. To help clinicians understand the current state of AI and sleep medicine, and to further enable these solutions to be adopted into clinical practice, a discussion panel was conducted on June 7, 2022, at the Associated Professional Sleep Societies Sleep Conference in Charlotte, North Carolina. The article is a summary of key discussion points from this session, including aspects of considerations for the clinician in evaluating AI-enabled solutions including but not limited to what steps might be taken both by the Food and Drug Administration and clinicians to protect patients, logistical issues, technical challenges, billing and compliance considerations, education and training considerations, and other unique challenges specific to AI-enabled solutions. Our summary of this session is meant to support clinicians in efforts to assist in the clinical care of patients with sleep disorders utilizing AI-enabled solutions.

CITATION

Bandyopadhyay A, Bae C, Cheng H, et al. Smart sleep: what to consider when adopting AI-enabled solutions in clinical practice of sleep medicine. J Clin Sleep Med. 2023;19(10):1823-1833.

Prevalence and clinical impacts of obstructive sleep apnea in patients with idiopathic pulmonary fibrosis: A single-center, retrospective study

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease with chronic, progressive lung fibrosis with a poor prognosis. Recent studies have reported a high prevalence of obstructive sleep apnea (OSA) in IPF patients and an association with poor prognosis. This study aimed to evaluate the prevalence, risk factors, and clinical effects on mortality of OSA in patients with IPF.

METHODS

Clinical data were retrospectively analyzed in 167 patients with IPF at Haeundae-Paik Hospital, Republic of Korea. A type 4 portable device was used to monitor OSA, and an apnea-hypopnea index of 5 events per sleep hour and above was diagnosed as OSA.

RESULTS

The mean follow-up period and age were 26.9 months and 71.4 years, respectively, with male predominance. OSA was confirmed in 108 patients (64.7%). Mild OSA was the most common (62.1%). Independent risk factors for OSA in the multivariate logistic regression analysis were age (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.02-1.13, p = 0.007), body weight (OR 1.05, 95% CI 1.02-1.09, p = 0.002), and risk based on the Berlin questionnaire (OR 2.76, 95% CI 1.12-6.80, p = 0.028). Shorter six-minute walk distance (6MWD) (hazard ratio [HR] 1.00, 95% CI: 1.00-1.00, p < 0.001), acute exacerbation (AE) (HR 13.83, 95% CI: 5.71-33.47, p < 0.001), and higher percentage of cumulative time with oxygen saturation below 90% in total sleep time (HR 1.08, 95% CI: 1.02-1.14, p = 0.007) were risk factors for mortality in IPF patients in the Cox regression analysis.

CONCLUSION

Approximately two-thirds of the IPF patients had OSA. Older age, higher body weight, and high risk based on the Berlin questionnaire were independent risk factors for OSA in IPF patients. Shorter 6MWD, experience of AE, and night hypoxemia during sleep were associated with a higher risk of mortality in patients with IPF.

Belun Ring (Belun Sleep System BLS-100): Deep learning-facilitated wearable enables obstructive sleep apnea detection, apnea severity categorization, and sleep stage classification in patients suspected of obstructive sleep apnea

GOAL AND AIMS

Our objective was to evaluate the performance of Belun Ring with second-generation deep learning algorithms in obstructive sleep apnea (OSA) detection, OSA severity categorization, and sleep stage classification.

FOCUS TECHNOLOGY

Belun Ring with second-generation deep learning algorithms REFERENCE TECHNOLOGY: In-lab polysomnography (PSG) SAMPLE: Eighty-four subjects (M: F = 1:1) referred for an overnight sleep study were eligible. Of these, 26% had PSG-AHI<5; 24% had PSG-AHI 5-15; 23% had PSG-AHI 15-30; 27% had PSG-AHI ≥ 30.

DESIGN

Rigorous performance evaluation by comparing Belun Ring to concurrent in-lab PSG using the 4% rule.

CORE ANALYTICS

Pearson's correlation coefficient, Student's paired t-test, diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, Cohen's kappa coefficient (kappa), Bland-Altman plots with bias and limits of agreement, receiver operating characteristics curves with area under the curve, and confusion matrix.

CORE OUTCOMES

The accuracy, sensitivity, specificity, and kappa in categorizing AHI ≥ 5 were 0.85, 0.92, 0.64, and 0.58, respectively. The accuracy, sensitivity, specificity, and Kappa in categorizing AHI ≥ 15 were 0.89, 0.91, 0.88, and 0.79, respectively. The accuracy, sensitivity, specificity, and Kappa in categorizing AHI ≥ 30 were 0.91, 0.83, 0.93, and 0.76, respectively. BSP2 also achieved an accuracy of 0.88 in detecting wake, 0.82 in detecting NREM, and 0.90 in detecting REM sleep.

CORE CONCLUSION

Belun Ring with second-generation algorithms detected OSA with good accuracy and demonstrated a moderate-to-substantial agreement in categorizing OSA severity and classifying sleep stages.

Validation of a single-use and reusable home sleep apnea test based on peripheral arterial tonometry compared to laboratory polysomnography for the diagnosis of obstructive sleep apnea

STUDY OBJECTIVES

The objective of this study was to independently validate a disposable and a reusable home sleep apnea test (HSAT) recording on peripheral arterial tonometry, compared to laboratory polysomnography (PSG), for the diagnosis of obstructive sleep apnea (OSA).

METHODS

115 participants undergoing PSG for suspected OSA were recruited and fitted with the two study devices (NightOwl, Ectosense, Belgium). After exclusions were applied and device failures were removed, data from 100 participants were analyzed. HSAT-derived apnea-hypopnea index (AHI), OSA severity category, total sleep time, and oxygen desaturation index 3% were compared to PSG.

RESULTS

Both study devices demonstrated satisfactory levels of agreement with minimal mean bias for determination of AHI and oxygen desaturation index 3% (disposable: AHI mean bias 2.04 events/h [95% limits of agreement -20.9 to 25.0], oxygen desaturation index 3% mean bias -0.21/h [-18.1 to 17.7]; reusable: AHI mean bias 2.91 events/h [-16.9 to 22.7], oxygen desaturation index 3% mean bias 0.77/h [-15.7 to 17.3]). Level of agreement diminished at higher AHI levels although misclassification for severe OSA occurred infrequently. Total sleep time level of agreement for the reusable HSAT was also satisfactory with minimal mean bias (4.18 minutes, -125.1 to 112.4), but the disposable HSAT was impacted by studies with high signal rejection (23.7 minutes, -132.7 to 180.1). Categorization of OSA severity demonstrated moderate agreement with laboratory PSG, with a kappa of 0.52 and 0.57 for the disposable and reusable HSATs respectively.

CONCLUSIONS

The two HSAT devices were comparable and performed well compared to laboratory PSG for the diagnosis of OSA.

CLINICAL TRIAL REGISTRATION

Registry: Australian New Zealand Clinical Trials Registry; Identifier: ANZCTR12621000444886.

CITATION

Lyne CJ, Hamilton GS, Turton ARE, et al. Validation of a single-use and reusable home sleep apnea test based on peripheral arterial tonometry compared to laboratory polysomnography for the diagnosis of obstructive sleep apnea. J Clin Sleep Med. 2023;19(8):1429-1435.

Evaluating an under-mattress sleep monitor compared to a peripheral arterial tonometry home sleep apnea test device in the diagnosis of obstructive sleep apnea

STUDY OBJECTIVES

To evaluate whether or not the apnea-hypopnea index (AHI) from a peripheral arterial tonometry (PAT) home sleep apnea test (HSAT) is equivalent to the AHI provided by the mean of one, three, or seven nights from the Withings Sleep Analyzer (WSA) under-mattress device.

METHODS

We prospectively enrolled patients with suspected OSA in whom a PAT-HSAT was ordered. Eligible patients used the WSA for seven to nine nights. PAT data were scored using the device's intrinsic machine learning algorithms to arrive at the AHI using both 3% and 4% desaturation criteria for hypopnea estimations (PAT3%-AHI and PAT4%-AHI, respectively). These were then compared with the WSA-estimated AHI (WSA-AHI).

RESULTS

Of 61 patients enrolled, 35 completed the study with valid PAT and WSA data. Of the 35 completers 16 (46%) had at least moderately severe OSA (PAT3%-AHI ≥ 15). The seven-night mean WSA-AHI was 2.13 (95%CI =  - 0.88, 5.14) less than the PAT3%-AHI, but 5.64 (95%CI = 2.54, 8.73) greater than the PAT4%-AHI. The accuracy and area under the receiver operating curve (AUC) using the PAT3%-AHI ≥ 15 were 77% and 0.87 and for PAT4%-AHI ≥ 15 were 77% and 0.85, respectively. The one-, three-, or seven-night WSA-AHI were not equivalent to either the 3% or 4% PAT-AHI (equivalency threshold of ± 2.5 using the two one-sided t-test method).

CONCLUSIONS

The WSA derives estimates of the AHI unobtrusively over many nights, which may prove to be a valuable clinical tool. However, the WSA-AHI over- or underestimates the PAT-AHI in clinical use, and the appropriate use of the WSA in clinical practice will require further evaluation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04778748.

Peripheral arterial tonometry versus polysomnography in suspected obstructive sleep apnoea

BACKGROUND

Polysomnography (PSG) is the gold standard for the diagnosis of obstructive sleep apnoea (OSA). Home sleep apnoea testing with peripheral arterial tonometry (PAT) is a recommended diagnostic alternative for patients with an increased risk for OSA. In a large clinical cohort, we investigated concordance and predictors for discordance in diagnosing OSA using PAT and PSG, and three-year cardiovascular risk in patients with discordant OSA diagnosis.

METHODS

Retrospective monocentric cohort study. Patients with a PAT AHI ≥ 5/h followed by an in-hospital PSG within three months were included. All patients with a PAT AHI ≥ 5/h but a PSG AHI < 5/h were classified as discordant. Patients with PAT and PSG AHI ≥ 5/h were classified as concordant. To ascertain cardiovascular risk, major adverse cardiovascular events (MACE) were analyzed in discordant patients and sex, age, body mass index (BMI) and cardiovascular disease-matched concordant patients over a follow-up time of 3.1 ± 0.06 years.

RESULTS

A total of 940 patients, 66% male with an average age of 55 ± 0.4 years and BMI of 31 ± 0.2 kg/m² were included. Agreement in OSA diagnosis was observed in 80% of patients (55% in mild and 86% in moderate and severe OSA). Factors significantly associated with a discordant diagnosis were female sex, younger age and lower BMI, but not comorbidities. There was no significant difference in MACE (p = 0.920) between discordant patients (n = 155) and matched concordant patients (n = 274) with or without therapy.

CONCLUSIONS

Concordance between PAT and PSG diagnosis of sleep apnoea is good, particularly in moderate and severe OSA. Predictors for discordant results between PAT and PSG were age, sex and BMI. MACE risk is similar in those with OSA diagnosed by PAT or PSG.

Detection and Prediction of Sleep Disorders by Covert Bed-Integrated RF Sensors

OBJECTIVE

Respiratory disturbances during sleep are a prevalent health condition that affects a large adult population. The gold standard to evaluate sleep disorders including apnea is overnight polysomnography, which requires a trained technician for live monitoring and post-processing scoring. Currently, the disorder events can hardly be predicted using the respiratory waveforms preceding the events. The objective of this paper is to develop an autonomous system to detect and predict respiratory events reliably based on real-time covert sensing.

METHODS

A bed-integrated radio-frequency (RF) sensor by near-field coherent sensing (NCS) was employed to retrieve continuous respiratory waveforms without user's awareness. Overnight recordings were collected from 27 patients in the Weill Cornell Center for Sleep Medicine. We extracted respiratory features to feed into the random-forest machine learning model for disorder detection and prediction. The technician annotation, derived from observation by polysomnography, was used as the ground truth during the supervised learning.

RESULTS

Apneic event detection achieved a sensitivity and specificity up to 88.6% and 89.0% for k-fold validation, and 83.1% and 91.6% for subject-independent validation. Prediction of forthcoming apneic events could be made up to 90 s in advance. Apneic event prediction achieved a sensitivity and specificity up to 81.3% and 82.1% for k-fold validation, and 80.5% and 82.4% for subject-independent validation. The most important features for event detection and prediction can be assessed in the learning model.

CONCLUSION

A bed-integrated RF sensor can covertly and reliably detect and predict apneic events.

SIGNIFICANCE

Predictive warning of the sleep disorders in advance can intervene serious apnea, especially for infants, servicemen, and patients with chronic conditions.

Clinical impact of manual scoring of peripheral arterial tonometry in patients with sleep apnea

PURPOSE

The objective was to analyze the clinical implications of manual scoring of sleep studies using peripheral arterial tonometry (PAT) and to compare the manual and automated scoring algorithms.

METHODS

Patients with suspected sleep-disordered breathing underwent sleep studies using PAT. The recordings were analyzed using a validated automated computer-based scoring and a novel manual scoring algorithm. The two methods were compared regarding sleep stages and respiratory events.

RESULTS

Recordings of 130 patients were compared. The sleep stages and time were not significantly different between the scoring methods. PAT-derived apnea-hypopnea index (pAHI) was on average 8.4 events/h lower in the manually scored data (27.5±17.4/h vs.19.1±15.2/h, p<0.001). The OSA severity classification decreased in 66 (51%) of 130 recordings. A similar effect was found for the PAT-derived respiratory disturbance index with a reduction from 31.2±16.5/h to 21.7±14.4/h (p<0.001), for automated and manual scoring, respectively. A lower pAHI for manual scoring was found in all body positions and sleep stages and was independent of gender and body mass index. The absolute difference of pAHI increased with sleep apnea severity, while the relative difference decreased. Pearson's correlation coefficient between pAHI and oxygen desaturation index (ODI) significantly improved from 0.89 to 0.94 with manual scoring (p<0.001).

CONCLUSIONS

Manual scoring results in a lower pAHI while improving the correlation to ODI. With manual scoring, the OSA category decreases in a clinically relevant proportion of patients. Sleep stages and time do not change significantly with manual scoring. In the authors' opinion, manual oversight is recommended if clinical decisions are likely to change.

Obstructive sleep apnoea-hypopnoea syndrome: state of the art

Obstructive sleep apnoea-hypopnoea syndrome (OSAHS) is an extremely common sleep-related breathing disorder (SRBD) characterised by complete or partial collapse of the upper airways. These nocturnal phenomena cause high-frequency hypoxemic desaturations (or intermittent hypoxia, IH) during sleep and alterations in gas exchange. The result of IH is the development or worsening of cerebro-cardio-vascular, metabolic and other diseases, which cause a high risk of death. Hence, OSAHS is a multifactorial disease affecting several organs and systems and presenting with various clinical manifestations involving different medical branches. Although it has been estimated that about one billion individuals worldwide are affected by OSAHS, this SRBD remains underestimated also due to misinformation regarding both patients and physicians. Therefore, this review aims to provide information on the main symptoms and risk factors for the detection of individuals at risk of OSAHS, as well as to present the diagnostic investigations to be performed and the different therapeutic approaches. The scientific evidence reported suggest that OSAHS is an extremely common and complex disorder that has a large impact on the health and quality of life of individuals, as well as on healthcare expenditure. Moreover, given its multifactorial nature, the design and implementation of diagnostic and therapeutic programmes through a multidisciplinary approach are necessary for a tailor-made therapy for each patient.

Portable Sleep Study Device Versus Polysomnography: A Meta-analysis

OBJECTIVE

To provide an updated comparison of apnea-hypopnea index (AHI), oxygen desaturation index (ODI), respiratory disturbance index (RDI), oxygen saturation (O₂ sat), and lowest oxyhemoglobin saturation (LSAT) measured by portable sleep study devices (PSSDs) compared to polysomnography (PSG).

DATA SOURCES

Primary studies were identified through PubMed, Scopus, CINAHL, and Cochrane.

REVIEW METHODS

A systematic review was performed by searching databases from inception through August 2021. Only studies examining simultaneous monitoring of a PSSD and PSG were included.  Respiratory indices AHI, ODI, RDI, O₂ sat, and LSAT was collected Meta-correlations and meta-regressions were conducted to compare sleep variable measurements between PSSD and PSG.

RESULTS

A total of 24 studies (N = 1644 patients) were included. The mean age was 49.5 ± 12.0 (range = 13-92), mean body mass index (BMI) was 30.4 ± 5.7 (range = 17-87), and 69.4% were male. Meta-correlation showed significant associations between PSSD and PSG for AHI (n = 655, r = .888; p < .001), ODI (n = 241, r = .942; p < .001), RDI (n = 313, r = .832; p < .001), O₂ sat (n = 171, r = .858; p < .001), and LSAT (n = 197, r = .930; p < .001). Meta-regressions indicated significant predictive correlations for AHI (n = 655; r = .96; p < .001), ODI (n = 740; r = .75; p = .031), RDI (n = 197; r = .99; p = .005), and LSAT (n = 197; r = .85; p = .030), but not for O₂ sat (n = 171; r = .31; p = .692).

CONCLUSIONS

Respiratory indices correlate strongly between PSSD and PSG, which is further supported by meta-regressions results. PSSD might be a valuable cost and time-saving OSA screening tool.

Central Sleep Apnea Detection by Means of Finger Photoplethysmography

Obstructive Sleep Apnea (OSA) and Central Sleep Apnea (CSA) are two types of Sleep Apnea (SA) with different etiologies and treatment options. Home sleep apnea testing based on photoplethysmography-derived peripheral arterial tonometry (PAT HSAT) has become the most widely deployed outpatient SA diagnostic method. Being able to differentiate between CSA and OSA based solely on photoplethysmography-data would further increase PAT HSAT's clinical utility. The present work proposes a method to detect CSA using finger photoplethysmography (PPG) data and evaluates the proposed method against simultaneous in-lab polysomnography (PSG).

METHODS

For 266 patients with a suspicion of SA, concurrent in-lab PSG and PPG data were acquired. The respiratory information embedded in the PPG data was extracted and used to train an ensemble of trees classifiers that predicts the central or obstructive nature of each respiratory event. The classifier performance was evaluated using patient-wise leave-one-out cross-validation where an expert analysis of the PSG served as ground truth. A second, independent analysis of the PSG was also evaluated against the ground truth to allow benchmarking of the PPG-based method.

RESULTS

The method achieved a sensitivity of 81%, a specificity of 99%, a positive predictive value of 90%, and a negative predictive value of 98% at the central apnea-hypopnea index cutoff of 10 events per hour of sleep.

CONCLUSION AND SIGNIFICANCE

The present study aimed to evaluate a method to detect CSA in SA patients using only PPG data which could be used to flag CSA which in turn may aid in more optimal therapy decision making.

Home Sleep Apnea Testing for the Diagnosis of Obstructive Sleep Apnea

A 50-year-old patient with epilepsy, hypertension, loud snoring, recent 50-lb weight gain, and abrupt awakenings with a feeling of breathlessness but no headaches or excessive daytime sleepiness presented with concerns. What would you do next?

Portable evaluation of obstructive sleep apnea in adults: A systematic review

Obstructive sleep apnea (OSA) is a significant healthcare burden affecting approximately one billion people worldwide. The prevalence of OSA is rising with the ongoing obesity epidemic, a key risk factor for its development. While in-laboratory polysomnography (PSG) is the gold standard for diagnosing OSA, it has significant drawbacks that prevent widespread use. Portable devices with different levels of monitoring are available to allow remote assessment for OSA. To better inform clinical practice and research, this comprehensive systematic review evaluated diagnostic performances, study cost and patients' experience of different levels of portable sleep studies (type 2, 3, and 4), as well as wearable devices and non-contact systems, in adults. Despite varying study designs and devices used, portable diagnostic tests are found to be sufficient for initial screening of patients at risk of OSA. Future studies are needed to evaluate cost effectiveness with the incorporation of portable diagnostic tests into the diagnostic pathway for OSA, as well as their application in patients with chronic respiratory diseases and other comorbidities that may affect test performance.

ERS technical standards for using type III devices (limited channel studies) in the diagnosis of sleep disordered breathing in adults and children

For more than three decades, type III devices have been used in the diagnosis of sleep disordered breathing in supervised as well as unsupervised settings. They have satisfactory positive and negative predictive values for detecting obstructive and central sleep apnoea in populations with moderately high pre-test probability of symptoms associated with these events. However, standardisation of commercially available type III devices has never been undertaken and the technical specifications can vary widely. None have been subjected to the same rigorous processes as most other diagnostic modalities in the medical field. Although type III devices do not include acquisition of electroencephalographic signals overnight, the minimum number of physical sensors required to allow for respiratory event scoring using standards outlined by the American Academy of Sleep Medicine remains debatable. This technical standard summarises data on type III studies published since 2007 from multiple perspectives in both adult and paediatric sleep practice. Most importantly, it aims to provide a framework for considering current type III device limitations in the diagnosis of sleep disordered breathing while raising research- and practice-related questions aimed at improving our use of these devices in the present and future.

Home sleep apnea testing with peripheral arterial tonometry to assess outcome in upper airway stimulation

STUDY OBJECTIVES

To determine whether home sleep apnea testing with peripheral arterial tonometry (HSAT-PAT) can be used in upper airway stimulation to evaluate therapy success.

METHODS

Data analysis from 50 consecutive patients receiving upper airway stimulation was performed. Baseline values were measured by polysomnography and HSAT-PAT. Follow-up was performed during and after titration (3-6 months) by polysomnography and HSAT-PAT and after 1 year by HSAT-PAT only. Primary outcome measures were reduction in the apnea-hypopnea index and oxygen desaturation index. In addition, an analysis of night-to-night variability for HSAT-PAT was performed.

RESULTS

All 50 patients completed their posttitration visit (3-6 months) and 41 patients completed the 1-year follow-up. In HSAT-PAT after 1 year, the mean apnea-hypopnea index (desaturation 3%) was reduced from 29.5 ± 17.1 events/h to 19.9 ± 13.1 events/h (P < .01) and the oxygen desaturation index (desaturation 4%) was reduced from 17.8 ± 12.6 events/h to 10.2 ± 8.3 events/h (P < .01). Therapy adherence after 1 year was high (6.6 ± 1.9 hours per night) and led to improvement in daytime sleepiness, meaning a reduction in the Epworth Sleepiness Scale score from 12.8 ± 5.4 to 5.9 ± 4.0 (P < .01). Analysis of night-to-night variability showed similar apnea-hypopnea index values between the 2 nights.

CONCLUSIONS

Upper airway stimulation was able to reduce the apnea-hypopnea index and oxygen desaturation index after 1 year, as assessed by full-night efficacy studies with HSAT-PAT. In addition, improvements in self-reported outcome parameters were observed. The importance of publishing the scoring criteria is highlighted and whether data are based on full-night efficacy studies or a selected period of time from a sleep study. This is a prerequisite for comparing data with other trials in the emerging field of upper airway stimulation.

CITATION

Hinder D, Schams SC, Knaus C, Tschopp K. Home sleep apnea testing with peripheral arterial tonometry to assess outcome in upper airway stimulation. J Clin Sleep Med. 2022;18(9):2197-2205.

Diagnostic accuracy of home sleep apnea testing using peripheral arterial tonometry for sleep apnea: A systematic review and meta-analysis

This study aimed to evaluate the diagnostic accuracy of home sleep apnea testing using peripheral arterial tonometry for sleep apnea as an alternative to polysomnography. We conducted a systematic review and meta-analysis of observational studies, randomized controlled trials, and diagnostic case-control studies examining the diagnostic accuracy of peripheral arterial tonometry by searching the CENTRAL, MEDLINE, EMBASE, ICTRP and ClinicalTrials.gov databases on 5 October 2021. We assessed the risk of bias of the included studies using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. A bivariate random-effects model was generated to derive the summary point estimates of sensitivity and specificity with 95% confidence intervals at different apnea-hypopnea index cutoffs. This meta-analysis included 13 studies (1227 participants, median prevalence of sleep apnea with apnea-hypopnea index ≥ 5 events per hr: 85%). The risk of bias in the included studies was low to moderate. The pooled sensitivity and specificity estimates were 96% (95% confidence interval: 93%-97%) and 44% (95% confidence interval: 32%-56%) at apnea-hypopnea index ≥ 5 events per hr, 88% (85%-91%) and 74% (63%-83%) at apnea-hypopnea index ≧ 15 events per hr, and 80% (66%-89%) and 90% (83%-95%) at apnea-hypopnea index ≧ 30 events per hr, respectively. Peripheral arterial tonometry resulted in a significant number of false negatives and false positives at any apnea-hypopnea index cutoff when applied to the median prevalence setting of the included studies. The inadequate sensitivity and specificity of peripheral arterial tonometry render it an unsuitable alternative to polysomnography for detecting sleep apnea for apnea-hypopnea index ≧ 5, 15 and 30 events per hr.

Transoral awake state neuromuscular electrical stimulation therapy for mild obstructive sleep apnea

Introduction

Obstructive sleep apnea (OSA) is a common disorder with major neurocognitive and cardiovascular sequelae. The treatment of symptomatic patients with mild OSA remains controversial given that adherence to positive airway pressure (PAP) has historically been suboptimal. With this notion in mind, we assessed a daily transoral neuromuscular electrical stimulation (NMES) device for individuals with mild OSA.

Methods

The sample represents a subset of participants with a baseline AHI 5–14.9 events/hour, drawn from a parent study which also included participants with primary snoring. Outcome measures for the current study included changes in apnea-hypopnea index (AHI), Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI) and snoring levels before and after use of the NMES. 

Results

Among 65 participants (68% men) with median age of 49 years (range 24 to 79) and median BMI of 27.7 kg/m2 (range 20 to 34), the NMES device was used daily for 6 weeks. We observed a significant improvement in the AHI from 10.2 to 6.8 events/hour among all participants and from 10.4 to 5.0 events/h among responders. Statistically significant improvements in the ESS, PSQI, objectively measured snoring, and bed partner-reported snoring were observed. Adherence among all participants was 85%.

Discussion

This NMES device has the benefit of being a treatment modality of daytime therapy which confers a high level of tolerability and patient acceptance. It alleviates the need for an in situ device during sleep and leads to improvements in OSA severity, snoring, and subjective sleep metrics, potentially crucial in mild OSA. Further studies are needed to define which individuals may benefit most from the device across the wider spectrum of OSA severity and assess long-term therapeutic outcomes.

Trial registration

ClinicalTrials.gov Identifier: NCT03829956.

A multicentric validation study of a novel home sleep apnea test based on peripheral arterial tonometry

STUDY OBJECTIVES

This paper reports on the multicentric validation of a novel FDA-cleared home sleep apnea test based on peripheral arterial tonometry (PAT HSAT).

METHODS

One hundred sixty-seven participants suspected of having obstructive sleep apnea (OSA) were included in a multicentric cohort. All patients underwent simultaneous polysomnography (PSG) and PAT HSAT, and all PSG data were independently double scored using both the recommended 1A rule for hypopnea, requiring a 3% desaturation or arousal (3% Rule), and the acceptable 1B rule for hypopnea, requiring a 4% desaturation (4% Rule). The double-scoring of PSG enabled a comparison of the agreement between PAT HSAT and PSG to the inter-rater agreement of PSG. Clinical endpoint parameters were selected to evaluate the device's ability to determine the OSA severity category. Finally, a correction for near-boundary apnea-hypopnea index values was proposed to adequately handle the inter-rater variability of the PSG benchmark.

RESULTS

For both the 3% and the 4% Rules, most endpoint parameters showed a close agreement with PSG. The 4-way OSA severity categorization accuracy of PAT HSAT was strong, but nevertheless lower than the inter-rater agreement of PSG (70% vs 77% for the 3% Rule and 78% vs 81% for the 4% Rule).

CONCLUSIONS

This paper reported on a multitude of robust endpoint parameters, in particular OSA severity categorization accuracies, while also benchmarking clinical performances against double-scored PSG. This study demonstrated strong agreement of PAT HSAT with PSG. The results of this study also suggest that different brands of PAT HSAT may have distinct clinical performance characteristics.

Correlations between home sleep apnea tests and polysomnography outcomes do not fully reflect the diagnostic accuracy of these tests

STUDY OBJECTIVES

The clinical performance of home sleep apnea tests (HSATs) can be described by their (diagnostic) accuracy, defined as the percentage agreement with the obstructive sleep apnea severity category (normal, mild, moderate, and severe) based on polysomnography. Rather than reporting on accuracy, there has been a strong reliance in the literature to report correlation coefficients between the apnea-hypopnea index of HSATs and polysomnography to support claims of diagnostic performance. This is surprising, as it has been well described that correlation coefficients are inadequate to evaluate equivalence between 2 parameters. The aim of this study was to systematically investigate the magnitude of the discrepancies between correlation coefficients and diagnostic accuracy reported in or retrievable from HSAT validation studies.

METHODS

We compared the discrepancy between accuracy and apnea-hypopnea index correlation coefficients of all validation papers that met the inclusion criteria. A total of 20 papers were retained, representing a participant pool of 1,652.

RESULTS

The weighted average apnea-hypopnea index correlation across all 20 papers was 0.82 and the weighted average accuracy was 0.61, highlighting a discrepancy of 0.21 and an overall misdiagnosis rate of 39%.

CONCLUSIONS

The results of our study confirm the need for increased scientific rigor in selecting primary performance endpoints to support clinical performance claims of HSATs.

CITATION

Massie F, Van Pee B, Bergmann J. Correlations between home sleep apnea tests and polysomnography outcomes do not fully reflect the diagnostic accuracy of these tests. J Clin Sleep Med. 2022;18(3):871-876.

A meta-analysis of diagnostic test performance of peripheral arterial tonometry studies

STUDY OBJECTIVES

The objective of this meta-analysis was to analyze agreement in apnea-hypopnea index (AHI) determination between peripheral arterial tonometry (PAT) and polysomnography (PSG) studies.

METHODS

Mean AHI bias and standard deviation (SD) extracted from Bland-Altman plots reported in studies was pooled in a meta-analysis, which was then used to calculate percentage errors of limit agreement (PE) in AHI determination by PAT using PSG AHI as the reference. Individual participant data (where reported in studies) was used to compute Cohen's kappa to assess agreement between PSG and PAT on sleep apnea severity and also for computing sensitivity and specificity of PAT at different AHI thresholds using PSG AHI as the reference.

RESULTS

From 17 studies and 1318 participants (all underwent simultaneous PSG and WatchPAT), a pooled mean AHI bias of 0.30 (standard error (SE) 0.74) and a WatchPAT AHI PE of 230% was calculated. Meta-analysis of Cohen's kappa for agreement between PSG and WatchPAT studies for classifying patients with no sleep apnea, mild, moderate or severe sleep apnea severity was 0.45 (SE 0.06), 0.29 (SE 0.05), 0.25 (SE 0.07) and 0.64 (SE 0.05), respectively. At AHI thresholds 5, 15 and 30, WatchPAT studies showed pooled sensitivities and specificities of 94.11% and 43.47%, 92.21% and 72.39% and 74.11% and 87.10%, respectively. Likelihood ratios were not significant at any AHI threshold.

CONCLUSIONS

The results of this meta-analysis suggest clinically significant discordance between WatchPAT and PSG measurements of AHI, significant sleep apnea severity misclassification by PAT studies and also poor diagnostic test performance.

Detection of obstructive sleep apnea using Belun Sleep Platform wearable with neural network-based algorithm and its combined use with STOP-Bang questionnaire

Many wearables allow physiological data acquisition in sleep and enable clinicians to assess sleep outside of sleep labs. Belun Sleep Platform (BSP) is a novel neural network-based home sleep apnea testing system utilizing a wearable ring device to detect obstructive sleep apnea (OSA). The objective of the study is to assess the performance of BSP for the evaluation of OSA. Subjects who take heart rate-affecting medications and those with non-arrhythmic comorbidities were included in this cohort. Polysomnography (PSG) studies were performed simultaneously with the Belun Ring in individuals who were referred to the sleep lab for an overnight sleep study. The sleep studies were manually scored using the American Academy of Sleep Medicine Scoring Manual (version 2.4) with 4% desaturation hypopnea criteria. A total of 78 subjects were recruited. Of these, 45% had AHI < 5; 18% had AHI 5-15; 19% had AHI 15-30; 18% had AHI ≥ 30. The Belun apnea-hypopnea index (bAHI) correlated well with the PSG-AHI (r = 0.888, P < 0.001). The Belun total sleep time (bTST) and PSG-TST had a high correlation coefficient (r = 0.967, P < 0.001). The accuracy, sensitivity, specificity in categorizing AHI ≥ 15 were 0.808 [95% CI, 0.703-0.888], 0.931 [95% CI, 0.772-0.992], and 0.735 [95% CI, 0.589-0.850], respectively. The use of beta-blocker/calcium-receptor antagonist and the presence of comorbidities did not negatively affect the sensitivity and specificity of BSP in predicting OSA. A diagnostic algorithm combining STOP-Bang cutoff of 5 and bAHI cutoff of 15 events/h demonstrated an accuracy, sensitivity, specificity of 0.938 [95% CI, 0.828-0.987], 0.944 [95% CI, 0.727-0.999], and 0.933 [95% CI, 0.779-0.992], respectively, for the diagnosis of moderate to severe OSA. BSP is a promising testing tool for OSA assessment and can potentially be incorporated into clinical practices for the identification of OSA. Trial registration: ClinicalTrial.org NCT03997916 https://clinicaltrials.gov/ct2/show/NCT03997916?term=belun+ring&draw=2&rank=1.

Phenotyping REM OSA by means of peripheral arterial tone-based home sleep apnea testing and polysomnography: A critical assessment of the sensitivity and specificity of both methods

The clinical relevance of rapid eye movement sleep-related obstructive sleep apnea (REM OSA) is supported by its associated adverse health outcomes and impact on optimal treatment strategies. To date, no assessment of REM OSA phenotyping performance has been conducted for any type of sleep testing technology. The objective of this study was to assess this for polysomnography and peripheral arterial tone-based home sleep apnea testing (PAT HSAT). In a dataset comprising 261 participants, the sensitivity and specificity of the agreement on REM OSA phenotyping was assessed for two independent scorings of polysomnography and a synchronously administered PAT HSAT. The sensitivity and specificity of REM OSA phenotyping were 0.87 and 0.89, respectively, for the polysomnography inter-scorer comparison, and 0.68 and 0.97 for the PAT HSAT on a single-night basis, using the conventional minimum required rapid eye movement sleep time of 30 min. Polysomnography-based REM OSA phenotyping was found to be sensitive and specific even for a single-night testing protocol. Peripheral arterial tone-based REM OSA phenotyping showed a lower sensitivity but a slightly higher specificity compared to polysomnography. In order to increase performance and conclusiveness of peripheral arterial tone-based REM OSA phenotyping, a multi-night protocol of 2-5 nights could be considered. Finally, the minimum required rapid eye movement sleep time could be lowered from the conventional 30 min to 15 min without significantly lowering REM OSA phenotyping sensitivity and specificity, while increasing the level of phenotyping conclusiveness.

Is it the time to expect long-term outcome data in addition to follow-up data for sleep apnea interventions?

CITATION

Hunasikatti M. Is it the time to expect long-term outcome data in addition to follow-up data for sleep apnea interventions? J Clin Sleep Med. 2021;17(8):1519-1520.

Sleep Study Measures on Postoperative Night 1 Following Implantation of the Hypoglossal Nerve Stimulator

OBJECTIVE

To examine the changes in measures of sleep apnea severity and hypoxemia on the first postoperative night following implantation of the hypoglossal nerve stimulator.

STUDY DESIGN

This was a single-arm prospective cohort study.

SETTING

A single academic sleep surgical practice.

METHODS

Subjects with moderate to severe obstructive sleep apnea underwent implantation of the hypoglossal nerve stimulator (HGNS) and were discharged to home the same day as surgery. A single-night WatchPAT study was performed on the night immediately following surgery (PON 1) and was compared to baseline sleep testing.

RESULTS

Twenty subjects who were an average of 58.6 ± 2.5 years old, were 25% female, and had a mean body mass index of 28.1 ± 0.9 kg/m² completed the study. Mean O₂ nadir at baseline was 79.6% ± 1.1% compared to 82.7% ± 0.9% (P = .013) on PON 1. One patient demonstrated a >10% worsening in O₂ nadir. Only 2 additional patients demonstrated a worsening in O₂ nadir on PON 1, each by only 1 percentage point. Neither mean time spent below SpO₂ 88% nor oxygen desaturation index (ODI) worsened postoperatively (mean time spent below oxygen saturation of 88%, 27.8 ± 7.85 vs 11.2 ± 5.2, P = .03; mean ODI, 29.6 ± 5.2/h vs 21.0 ± 5.4/h, P = .10). Mean obstructive apnea hypopnea index (AHI) was no worse (40.6 ± 4.7/h to 28.7 ± 4.2/h, P = .02), with only 2 patients experiencing an obstructive AHI >20% more severe than baseline. Only 1 patient demonstrated a clinically meaningful increase in central AHI on PON 1.

CONCLUSIONS

Overall, AHI and measures of nocturnal hypoxemia are stable, if not improved, on PON 1 following HGNS implantation. These findings support the safety of same-day discharge following implantation of the hypoglossal nerve stimulator.

Evaluation and Management of Adults with Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea syndrome (OSAS) is a common and underdiagnosed medical condition characterized by recurrent sleep-dependent pauses and reductions in airflow. While a narrow, collapsible oropharynx plays a central role in the pathophysiology of OSAS, there are other equally important nonanatomic factors including sleep-stage dependent muscle tone, arousal threshold, and loop gain that drive obstructive apneas and hypopneas. Through mechanisms of intermittent hypoxemia, arousal-related sleep fragmentation, and intrathoracic pressure changes, OSAS impacts multiple organ systems. Risk factors for OSAS include obesity, male sex, age, specific craniofacial features, and ethnicity. The prevalence of OSAS is rising due to increasing obesity rates and improved sensitivity in the tools used for diagnosis. Validated questionnaires have an important but limited role in the identification of patients that would benefit from formal testing for OSA. While an in-laboratory polysomnography remains the gold standard for diagnosis, the widespread availability and accuracy of home sleep apnea testing modalities increase access and ease of OSAS diagnosis for many patients. In adults, the most common treatment involves the application of positive airway pressure (PAP), but compliance continues to be a challenge. Alternative treatments including mandibular advancement device, hypoglossal nerve stimulator, positional therapies, and surgical options coupled with weight loss and exercise offer possibilities of an individualized personal approach to OSAS. Treatment of symptomatic patients with OSAS has been found to be beneficial with regard to sleep-related quality of life, sleepiness, and motor vehicle accidents. The benefit of treating asymptomatic OSA patients, particularly with regard to cardiovascular outcomes, is controversial and more data are needed.

Improving the performance of peripheral arterial tonometry-based testing for the diagnosis of obstructive sleep apnea

Outside sleep laboratory settings, peripheral arterial tonometry (PAT, eg, WatchPat) represents a validated modality for diagnosing obstructive sleep apnea (OSA). We have shown before that the accuracy of home sleep apnea testing by WatchPat 200 devices in diagnosing OSA is suboptimal (50%-70%). In order to improve its diagnostic performance, we built several models that predict the main functional parameter of polysomnography (PSG), Apnea Hypopnea Index (AHI). Participants were recruited in our Sleep Center and underwent concurrent in-laboratory PSG and PAT recordings. Statistical models were then developed to predict AHI by using robust functional parameters from PAT-based testing, in concert with available demographic and anthropometric data, and their performance was confirmed in a random validation subgroup of the cohort. Five hundred synchronous PSG and WatchPat sets were analyzed. Mean diagnostic accuracy of PAT was improved to 67%, 81% and 85% in mild, moderate-severe or no OSA, respectively, by several models that included participants' age, gender, neck circumference, body mass index and the number of 4% desaturations/hour. WatchPat had an overall accuracy of 85.7% and a positive predictive value of 87.3% in diagnosing OSA (by predicted AHI above 5). In this large cohort of patients with high pretest probability of OSA, we built several models based on 4% oxygen desaturations, neck circumference, body mass index and several other variables. These simple models can be used at the point-of-care, in order to improve the diagnostic accuracy of the PAT-based testing, thus ameliorating the high rates of misclassification for OSA presence or disease severity.