Adherence to Positive Airway Therapy After Switching From CPAP to ASV: A Big Data Analysis

Early sleep apnea treatment in stroke (eSATIS) - a multicentre, randomised controlled, rater-blinded, clinical trial: The association of post-stroke cognition with sleep-disordered breathing and its treatment

Sleep-disordered breathing (SDB) is linked to cognitive dysfunction. Although SDB is common in stroke patients, the impact of SDB and its early treatment on cognitive functioning after stroke remains poorly investigated. Therefore, we explored the association between SDB and post-stroke cognitive functioning, including the impact of early SDB treatment with adaptive servo-ventilation (ASV) on cognitive recovery from acute event to 3 months post-stroke. We used data from two studies, which included ischaemic stroke patients (n = 131) and no-stroke controls (n = 37) without SDB (apnea-hypopnea index, AHI <5/h) and with SDB (AHI≥20/h). Cognitive functioning was assessed within 7 days and 3 months post-stroke in stroke patients, or at study inclusion in no-stroke control group, respectively. Stroke patients with SDB were randomized to ASV treatment (ASV+) or usual care (ASV-). Linear regression adjusted for main confounders assessed the impact of SDB and its treatment on cognitive recovery. The intention-to-treat analysis did not show significant associations of SDB ASV+ (n = 30) versus SDB ASV- (n = 29) with cognitive recovery. In an exploratory subanalysis, compliant SDB ASV+ (n = 14) versus SDB ASV- showed improvements with ASV in visual memory and cognitive flexibility. Combining the stroke and non-stroke datasets, SDB (n = 85) versus no-SDB (n = 83) was associated with deficits in visual memory and response inhibition independently of stroke. SDB ASV- versus no-SDB (n = 51) was associated with less improvement in visual memory. There was no substantial evidence for benefits of intention-to-treat ASV on cognitive recovery. Exploratory analysis indicated that compliant ASV treatment could benefit visual memory and cognitive flexibility, whereas untreated SDB could contribute to a poor recovery of visual memory.

The Repeatability of Pharyngeal Opening Pressure Under Drug-Induced Sleep Endoscopy

OBJECTIVE

Pharyngeal opening pressure (PhOP) is a measure of upper airway collapsibility that can be obtained during drug-induced sleep endoscopy (DISE) using a continuous positive airway pressure (CPAP) titration. However, the stability of PhOP over the course of sedation during DISE remains unclear. This study aims to compare repeat measures of PhOP over the course of DISE.

STUDY DESIGN

Single arm prospective study.

SETTING

Single tertiary care institution.

METHODS

Patients had 2 CPAP titrations while undergoing DISE. Collected data included patient demographics, PhOP, patient sedation index (PSI), and duration of and between CPAP titrations. t Tests, test-retest coefficient analysis, and repeated measures correlation were performed.

RESULTS

Twenty-five patients completed the study between 2022 and 2023 with 22 patients having sedation depth (PSI) recording. Most were male (76%), obese (average body mass index: 30.24 kg/m2), with severe obstructive sleep apnea (average apnea-hypopnea index: 39.8 events/hr). Test-retest analysis showed good-excellent correlation between PhOP values (intraclass correlation coefficient = 0.892, P < .0001, n = 25). Average time between CPAP titrations was 15 minutes to 6 seconds. Over that time, PhOP increased by an average of 0.72 cmH2O (P = .06, n = 25) and PSI decreased by 9.5 units (P = .01, n = 22). Repeated measures correlation showed a weak negative correlation between PhOP and PSI (r = -.45, P = .03, n = 22).

CONCLUSION

The results showed repeatability of PhOP values over the course of DISE. When adjusted for sedation depth (PSI), deeper sedation was weakly associated with greater PHOP. However, the magnitude of this change was small and we conclude that PhOP remains relatively stable over the course of DISE (Effects of Lung Volume on Upper Airway Patency During DISE [DISE-Pulm], NCT05350332, clinicaltrials.gov).

Effects of oropharyngeal exercises on CPAP compliance: A prospective intervention study

PURPOSE

To investigate the effects of oropharyngeal exercise on continuous positive airway pressure (CPAP) compliance in patients with moderate to severe obstructive sleep apnea over a period of 6 months.

MATERIALS AND METHODS

This study was conducted as a prospective, observational, and interventional investigation. A total of 70 patients with moderate to severe obstructive sleep apnea were randomly assigned to either the oropharyngeal exercise group (n = 44) or the sham-therapy group (n = 26). The compliance of the enrolled patients with CPAP therapy was assessed at baseline, 3-month follow-up and 6-month follow-up. Objective sleep data, questionnaire and CPAP use time were collected over a half-year period (i.e., baseline, 6 months, and 12 months).

RESULTS

The study found that the average use time of CPAP within one month was significantly longer in the oropharyngeal exercises group compared to the sham-therapy group at the 3-month assessment (5.5 ± 1.2 vs 4.8 ± 1.3 h per night; p=0.030), and much significantly longer at 6-months assessment (6.0 ± 1.4 vs 4.9 ± 1.3 h per night; p=0.001). Furthermore, the average use time of CPAP increased over time, with the oropharyngeal exercises group exhibiting a more pronounced growth from baseline to the six-month follow-up (4.8 ± 1.0 h per night to 6.0 ± 1.3 h per night, p < 0.001) compared to the sham-therapy group (4.8 ± 1.3 h per night to 4.9 ± 1.3 h per night, p=0.952). Additionally, the oropharyngeal exercise group demonstrated an improvement in the Epworth sleepiness scale compared to the sham-therapy group at the 3-month follow-up (6.0 ± 2.0 vs 8.8 ± 3.2; p < 0.001), as well as decreased significantly at 6-month follow-up (p = 0.032).

CONCLUSIONS

CPAP adherence can be improved with oropharyngeal exercises therapy among moderate to severe OSA patients. Notably, the average duration of CPAP usage and reduction in daytime sleepiness were maintained even after six months of oropharyngeal exercise therapy.

Central sleep apnea: emphasizing recognition and differentiation

INTRODUCTION

Central sleep apnea (CSA) is a sleep-related breathing disorder in which the effort to breathe is intermittently diminished or absent. CSA is a common disorder among patients with different cardiovascular disorders, including heart failure. In addition, a growing number of medications have been shown to induce CSA and CSA can emerge after initiation of treatment for obstructive sleep apnea. Accumulating evidence shows that CSA is a heterogeneous disorder with individual differences in clinical and biological characteristics and/or underlying pathophysiological mechanisms.

AREAS COVERED

This narrative review offers an overview of the diagnostic aspects and classification of CSA, with an emphasis on heart failure patients, patients with CSA due to a medication and treatment-emergent CSA. The importance of evaluation of prognostic biomarkers in patients with different types of CSA is discussed. This narrative review synthesizes literature on CSA sourced from the PubMed database up to February 2024.

EXPERT OPINION

CSA presents a remarkably diverse disorder, with treatment modalities exhibiting potentially varied efficacy across its various phenotypes. This highlights the imperative for tailored management strategies that are rooted in phenotype classification.

Air pollution, weather and positive airway pressure treatment adherence in adults with sleep apnea: a retrospective community-based repeated-measures longitudinal study

We assessed the relation between air pollution, weather, and adherence to positive airway pressure (PAP) therapy in a retrospective community-based repeated-measures study of adults with obstructive sleep apnea who purchased PAP devices from a registered provider between 2013 and 2017 (Ottawa, Ontario, Canada) and had at least one day of data. Daily PAP-derived data, air pollution, and weather databases were linked using postal code. The exposures were mean nocturnal (8:00 p.m. to 8:00 a.m.) (i) residential concentrations of nitrogen dioxide (NO2 ), fine particulate matter <=2.5 μm (PM2.5 ), ozone (O3 ), and Air Quality Health Index (AQHI), and (ii) temperature, relative humidity, and barometric pressure. Covariates in the main model were demographics, season, exposure year, and PAP therapy mode. We analysed 8148 adults (median age of 54 years and 61% men) and 2,071,588 days of data. Based on daily data, the median (interquartile range) daily PAP usage was 416 (323-487) min. Using mixed-effect regression analyses to incorporate daily data and clustering by individuals, we found a statistically significant decrease in adherence for increased levels of NO2 , PM2.5 , and AQHI. The largest effect was for NO2 : a decrease in daily PAP use while comparing the highest versus lowest quartiles (Qs) was 3.4 (95% confidence interval [CI] 2.8-3.9) min. Decreased PAP adherence was also associated with increased temperature (Q4 versus Q1: 2.6 [95% CI: 1.5-3.7] min) and decreased barometric pressure (Q1 versus Q4: 2.0 [95% CI 1.5-2.5] min). We observed modest but statistically significant acute effects of air pollution and weather on daily PAP adherence.

CPAP resumption after a first termination and impact on all-cause mortality in France

BACKGROUND

Continuation of continuous positive airway pressure (CPAP) therapy after initial prescription has been shown to reduce all-cause mortality versus therapy termination. However, there is a lack of data on the rates and impact of resuming CPAP in patients with obstructive sleep apnoea (OSA). This analysis determined the prevalence of CPAP resumption in the year after termination, characterised determinants of CPAP resumption, and examined the impact of CPAP resumption on all-cause mortality.

METHODS

French national health insurance reimbursement system data for adults aged ≥18 years were used. CPAP prescription was identified by specific treatment codes. Patients who resumed CPAP after first therapy termination and continued to use CPAP for 1 year were matched with those who resumed CPAP then terminated therapy for a second time.

RESULTS

Out of 103 091 individuals with a first CPAP termination, 26% resumed CPAP over the next 12 months, and 65% of these were still using CPAP 1 year later. Significant predictors of CPAP continuation after resumption included male sex, hypertension and CPAP prescription by a pulmonologist. In the matched population, the risk of all-cause death was 38% lower in individuals who continued using CPAP after therapy resumption versus those who had a second therapy discontinuation (hazard ratio 0.62, 95% CI 0.48-0.79; p=0.0001).

CONCLUSION

These data suggest that individuals with OSA who fail initial therapy with CPAP should be offered a second trial with the device to ensure that effective therapy is not withheld from those who might benefit.

FACE study: 2-year follow-up of adaptive servo-ventilation for sleep-disordered breathing in a chronic heart failure cohort

BACKGROUND

Sleep-disordered breathing (SDB) is a common comorbidity in patients with heart failure (HF) and is associated with worse prognosis.

OBJECTIVES

This study evaluated the effects of adaptive servo-ventilation (ASV) on morbidity and mortality in a large heterogeneous population of HF patients with different etiologies/phenotypes.

METHODS

Consecutive HF patients with predominant central sleep apnea (± obstructive sleep apnea) indicated for ASV were included; the control group included patients who refused or stopped ASV before three months follow-up. Six homogenous clusters were determined using the latent class analysis (LCA) method. The primary endpoint was time to composite first event (all-cause death, lifesaving cardiovascular intervention, or unplanned hospitalization for worsening of chronic HF).

RESULTS

Of 503 patients at baseline, 324 underwent 2-year follow-up. Compared to control group, 2-year primary endpoint event-free survival was significantly greater in patients in ASV group only in univariable analysis (1.67, 95% [1.12-2.49]; p = 0.01). Secondary endpoints, event-free of cardiovascular death or heart failure-related hospitalization and all-cause death or all-cause hospitalization were positively impacted by ASV (univariate and multivariable analysis). LCA identified two groups, with preserved and mid-range left ventricular ejection fraction (LVEF) and severe hypoxia, in whom ASV increase prognosis benefit.

CONCLUSIONS

Patients with HF and SDB are a highly heterogeneous group identified using LCA. Systematic deep phenotyping is essential to ensure that ASV is prescribed to those benefit from therapy, as ASV use in patients with severe hypoxic burden and those with HFpEF was associated with a significant reduction in cardiovascular events and mortality.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT01831128.

Predictors of Initial CPAP Prescription and Subsequent Course with CPAP in Patients with Central Sleep Apneas at a Single Center

PURPOSE

Guidelines recommend considering an initial trial of continuous positive airway pressure (CPAP) to treat central sleep apnea (CSA). However, practice patterns vary widely. This study investigated predictors for an initial trial of CPAP in patients with central apneas and whether those factors predict adequate treatment response in patients receiving an initial CPAP trial.

METHODS

Charts of patients receiving a diagnostic code for CSA following a sleep study during 2016-2018 at a single center were reviewed. Patient factors, initial treatment prescriptions, and subsequent changes to therapy were extracted from electronic health records. Regression models were used to estimate factors associated with an initial CPAP prescription and the likelihood of an adequate CPAP response (no subsequent therapy change and no discontinuation of therapy) among patients prescribed CPAP.

RESULTS

429/588 (73%) patients with central apneas received an initial trial of CPAP. Younger age, diagnosis by home sleep testing, non-opiate etiology of central apneas, and a lower proportion of central apneas at diagnosis were independently associated with a higher likelihood of an initial CPAP trial. A lower proportion of central apneas was associated with a higher probability of adequate response, while current smoking and opiate-related central apneas predicted an unsuccessful CPAP trial. A new finding was that older age predicted a lower likelihood of an initial CPAP prescription but did not predict an unsatisfactory response to CPAP.

CONCLUSION

Clinicians may incorrectly weigh certain clinical and sleep study characteristics when deciding whether to trial CPAP for patients with central apneas.

Predictors of Initial CPAP Prescription and Subsequent Course with CPAP in Patients with Central Sleep Apneas

Purpose

Guidelines recommend considering an initial trial of continuous positive airway pressure (CPAP) to treat central sleep apnea (CSA). However, practice patterns vary widely. This study investigated predictors for an initial trial of CPAP in patients with central apneas and whether those factors predict adequate treatment response in patients receiving an initial CPAP trial.

Methods

Charts of patients receiving a diagnostic code for CSA following a sleep study during 2016-2018 at a single center were reviewed. Patient factors, initial treatment prescriptions, and subsequent changes to therapy were extracted from electronic health records. Regression models were used to estimate factors associated with an initial CPAP prescription and the likelihood of an adequate CPAP response (no subsequent therapy change or nonadherence) among patients prescribed CPAP.

Results

429/588 (73%) patients with central apneas received an initial trial of CPAP. Younger age, diagnosis by home sleep testing, non-opiate etiology of central apneas, and a lower proportion of central apneas at diagnosis were independently associated with a higher likelihood of an initial CPAP trial. A lower proportion of central apneas was associated with a higher probability of adequate response, while current smoking and opiate-related central apneas predicted an unsuccessful CPAP trial. A new finding was that older age predicted a lower likelihood of an initial CPAP prescription but did not predict a suboptimal response to CPAP.

Conclusion

Clinicians may incorrectly weigh certain clinical and sleep study characteristics when deciding whether to trial CPAP for patients with central apneas.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

The individual and societal price of non-adherence to continuous positive airway pressure, contributors and strategies for improvement

INTRODUCTION

Continuous positive airway pressure (CPAP) is the first line therapy for obstructive sleep apnea (OSA). CPAP is highly effective for improving symptoms and quality of life but the major issue is adherence, with up to 50% of OSA discontinuing CPAP in the first 3 years after CPAP initiation.

AREAS COVERED

We present the individual and societal cost of non-adherence to CPAP, factors associated with non-adherence to CPAP, as well as current strategies for improving adherence including telehealth, couples-based interventions and behavioral interventions. We also report on challenges and pitfalls for the visualization and analysis of CPAP remote monitoring platforms.

EXPERT OPINION

CPAP termination rates and adherence to therapy remain major issues despite technical improvements in CPAP devices. The individual and societal price of non-adherence to CPAP for OSA patients goes beyond excessive sleepiness and includes cardiovascular events, all-cause mortality, and increased health costs. Strategies for improving CPAP adherence should be individually tailored and aim to also improve lifestyle habits including physical activity and nutrition. Access to these strategies should be supported by refining visualization dashboards of CPAP remote monitoring platforms, and by disseminating telehealth and innovative analytics, including artificial intelligence.

Diagnostic and therapeutic approach of central sleep apnea in heart failure - the role of adaptive servo-ventilation. A statement of the Portuguese society of pulmonology and the Portuguese sleep association

It is known that patients with heart failure (HF) have an increased risk of developing central sleep apnoea (CSA), with Cheyne-Stokes respiration. The development of servo-ventilation aimed to treat CSA and improve the quality of life (QoL) of these patients. A large randomized clinical study, SERVE-HF, was conducted in order to test this theory in patients with HF and reduced ejection fraction (HFrEF). The results from this trial seemed to indicate that, in these patients, there was no beneficial effect of the assisted ventilation in CSA treatment. More surprisingly, an increased rate of all-cause or cardiovascular mortality was observed. This has led to dramatic changes in clinical practice, with decreased frequency of servo-ventilation prescription across Europe, including Portugal, due to changes in the guidelines. However, SERVE-HF was conducted only in severe systolic HF patients with CSA, and caution must be taken when extrapolating these results to HF patients with preserved ejection fraction or CSA patients without HF. The study also showed poor adherence, methodological and statistical gaps, including study design, patient selection, data collection and analysis, treatment adherence, and group crossovers, which have not been discussed in the trial as potential confounding factors and raise several concerns. Moreover, the adaptive servo-ventilation (ASV) device used in SERVE-HF was unable to lower the minimum support pressure below 3 mm H₂0, and this has been suggested as one of the probable contributing reasons to the excess mortality observed in this study. This limitation has since been solved, and this ASV device is no longer used. This paper describes the results of a Portuguese Task Force on the treatment of central sleep apnoea in patients with chronic HF.

Brazilian Thoracic Association Consensus on Sleep-disordered Breathing

Sleep is essential for the proper functioning of all individuals. Sleep-disordered breathing can occur at any age and is a common reason for medical visits. The objective of this consensus is to update knowledge about the main causes of sleep-disordered breathing in adult and pediatric populations, with an emphasis on obstructive sleep apnea. Obstructive sleep apnea is an extremely prevalent but often underdiagnosed disease. It is often accompanied by comorbidities, notably cardiovascular, metabolic, and neurocognitive disorders, which have a significant impact on quality of life and mortality rates. Therefore, to create this consensus, the Sleep-Disordered Breathing Department of the Brazilian Thoracic Association brought together 14 experts with recognized, proven experience in sleep-disordered breathing.

The Pathogenesis of Central and Complex Sleep Apnea

PURPOSE

The purpose of this article is to review the recent literature on central apnea. Sleep disordered breathing (SDB) is characterized by apneas (cessation in breathing), and hypopneas (reductions in breathing), that occur during sleep. Central sleep apnea (CSA) is sleep disordered breathing in which there is an absence or diminution of respiratory effort during breathing disturbances while asleep. In obstructive sleep apnea (OSA), on the other hand, there is an absence of flow despite ongoing ventilatory effort.

RECENT FINDINGS

Central sleep apnea is a heterogeneous disease with multiple clinical manifestations. OSA is by far the more common condition; however, CSA is highly prevalent among certain patient groups. Complex sleep apnea (CompSA) is defined as the occurrence/emergence of CSA upon treatment of OSA. Similarly, there is considerable overlap between CSA and OSA in pathogenesis as well as impacts. Thus, understanding sleep disordered breathing is important for many practicing clinicians.

Evaluation of the Ocular Surface and Meibomian Gland in Obstructive Sleep Apnea Hypopnea Syndrome

Purpose

To assess the ocular surface and meibomian gland (MG) of patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and to explore the effects of surgery for OSAHS on the ocular surface and MG.

Methods

Based on the apnea hypopnea index (AHI), 21 patients with mild OSAHS (Group A, 5/h ≤ AHI < 15/h), 20 patients with moderate OSAHS (Group B, 15/h ≤ AHI < 30/h), 62 patients with severe OSAHS (Group C, AHI ≥ 30/h) were examined. The ocular surface and MG were evaluated using Keratograph 5M. In addition, detailed Ophthalmic examination including visual acuity, refraction, slit-lamp examination of the anterior segment, corneal fluorescein staining (CFS), ocular surface disease index (OSDI) scoring, Schirmer I test (SIT) and serum lipid measurement was performed. For OSAHS patients with dry eye syndrome (DES) who underwent uvulopalatopharyngoplasty for improving AHI, the conditions of the ocular surface and MG were compared before surgery and 3 months after surgery. Only the data of the right eyes were analyzed.

Results

There were no significantly different in the OSDI score, tear meniscus height (TMH), or loss ratio of the lower eyelid (LRLE) among these groups. The first non-invasive tear film breakup time (fNIBUT), average non-invasive tear film breakup time (avNIBUT), bulbar redness index (BRI), lipid layer grading (LLG), CFS, plugged orifices and distortion in MG, the loss ratio of upper eyelid (LRUE), and the incidence of DES, floppy eyelid syndrome (FES) and meibomian gland dysfunction (MGD) showed significant differences between Groups A and C (p = 0.015, p = 0.018, p < 0.001, p = 0.022, p = 0.036, p = 0.007, p = 0.019, p = 0.017, p = 0.045, p = 0.013, and p = 0.029, respectively). The SIT in the Group A was significantly higher than in Group B (p = 0.025) and in Group C (p < 0.001). In the correlation analyses, the fNIBUT, avNIBUT, SIT and LLG had negative correlations with the AHI (p = 0.013, p = 0.010, p = 0.003, p < 0.001, and p = 0.006, respectively). The BRI, CFS and LRUE were positively correlated with the AHI (p = 0.006, p = 0.007, and p = 0.046, respectively). Three months after surgery, there were no significant differences in the ocular surface or MG.

Conclusion

Patients with severe OSAHS have poor stability of tear film and are prone to lipid-deficient dry eye as a result of the loss of meibomian gland. By improving the AHI, the ocular surface damage of OSAHS patients cannot be reversed in a short time.

APAP, BPAP, CPAP, and New Modes of Positive Airway Pressure Therapy

Positive airway pressure (PAP) is the primary treatment of sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. Just as clinicians use pharmacological mechanism of action and pharmacokinetic data to optimize medication therapy for an individual, understanding how PAP works and choosing the right mode and device are critical to optimizing therapy in an individual patient. The first section of this chapter will describe the technology inside PAP devices that is essential for understanding the algorithms used to control the airflow and pressure. The second section will review how different comfort settings including ramp and expiratory pressure relief and modes of PAP therapy including continuous positive airway pressure (CPAP), autotitrating CPAP, bilevel positive airway pressure, adaptive servoventilation, and volume-assured pressure support control the airflow and pressure. Proprietary algorithms from several different manufacturers are described. This chapter derives its descriptions of algorithms from multiple sources including literature review, manufacture publications and websites, patents, and peer-reviewed device comparisons and from personal communication with manufacturer representatives. Clinical considerations related to the technological aspects of the different algorithms and features will be reviewed.

Obstructive sleep apnea

Obstructive sleep apnea (OSA) is a disease that results from loss of upper airway muscle tone leading to upper airway collapse during sleep in anatomically susceptible persons, leading to recurrent periods of hypoventilation, hypoxia, and arousals from sleep. Significant clinical consequences of the disorder cover a wide spectrum and include daytime hypersomnolence, neurocognitive dysfunction, cardiovascular disease, metabolic dysfunction, respiratory failure, and pulmonary hypertension. With escalating rates of obesity a major risk factor for OSA, the public health burden from OSA and its sequalae are expected to increase, as well. In this chapter, we review the mechanisms responsible for the development of OSA and associated neurocognitive and cardiometabolic comorbidities. Emphasis is placed on the neural control of the striated muscles that control the pharyngeal passages, especially regulation of hypoglossal motoneuron activity throughout the sleep/wake cycle, the neurocognitive complications of OSA, and the therapeutic options available to treat OSA including recent pharmacotherapeutic developments.

Sleep apnoea and ischaemic stroke: current knowledge and future directions

Sleep apnoea, one of the most common chronic diseases, is a risk factor for ischaemic stroke, stroke recurrence, and poor functional recovery after stroke. More than half of stroke survivors present with sleep apnoea during the acute phase after stroke, with obstructive sleep apnoea being the most common subtype. Following a stroke, sleep apnoea frequency and severity might decrease over time, but moderate to severe sleep apnoea is nevertheless present in up to a third of patients in the chronic phase after an ischaemic stroke. Over the past few decades evidence suggests that treatment for sleep apnoea is feasible during the acute phase of stroke and might favourably affect recovery and long-term outcomes. Nevertheless, sleep apnoea still remains underdiagnosed and untreated in many cases, due to challenges in the detection and prediction of post-stroke sleep apnoea, uncertainty as to the optimal timing for its diagnosis, and a scarcity of clear treatment guidelines (ie, uncertainty on when to treat and the optimal treatment strategy). Moreover, the pathophysiology of sleep apnoea associated with stroke, the proportion of stroke survivors with obstructive and central sleep apnoea, and the temporal evolution of sleep apnoea subtypes following stroke remain to be clarified. To address these shortcomings, the management of sleep apnoea associated with stroke should be integrated into a multidisciplinary diagnostic, treatment, and follow-up strategy.

A longitudinal study of the accuracy of positive pressure therapy machine-detected apnea-hypopnea events

STUDY OBJECTIVES

During positive airway pressure (PAP) therapy for sleep apnea syndromes, the machine detected respiratory event index (REI_FLOW) is an important method for clinicians to evaluate the beneficial effects of PAP. There are concerns about the accuracy of this detection, which also confounds a related question-how common and severe are residual events on PAP.

METHODS

Subjects with OSA who underwent a split night polysomnography were recruited prospectively. Those treated with PAP and tracked by the EncoreAnywhere system were analyzed. The ones who stopped PAP within one month were excluded for this analysis. Compliance, therapy data and waveform data were analyzed. Machine detected versus manually scored events were compared at the 1st, 3rd, 6th and 12th month from PAP initiation. Logistic regression was used to determine factors associated with a high REI_FLOW difference.

RESULTS

One hundred and seventy-nine patients with a mean age 59.06 ± 13.97 years old, median body mass index 33.60 (29.75-38.75) kg/m², and median baseline AHI 46.30 (31.50-65.90) times/hour were included. The difference between the machine detected REI_FLOW and manually scored REI_FLOW was 10.72 ±8.43 in the first month and remained stable for up to 12 months. Male sex and large leak ≥ 1.5% were more frequent in patients who had an REI_FLOW difference of ≥ 5 / hour of use. A titration arousal index ≥ 15/ hour of sleep, and higher ratio of unstable to stable breathing were also associated with an REI_FLOW difference ≥ 5 times/hour of use.

CONCLUSIONS

There is a substantial and sustained difference between manual and automated event estimates during PAP therapy, and some associated factors were identified.

Characterizing respiratory parameters, settings, and adherence in real-world patients using adaptive servo ventilation therapy: big data analysis

STUDY OBJECTIVES

There is minimal guidance around how to optimize inspiratory positive airway pressure (IPAP) levels during use of adaptive servo ventilation (ASV) in clinical practice. This real-world data analysis investigated the effects of IPAP and minimum pressure support settings on respiratory parameters and adherence in ASV-treated patients.

METHODS

A United States-based telemonitoring database was queried for patients starting ASV between August 1, 2014 and November 30, 2019. Patients meeting the following criteria were included: United States-based patients aged ≥ 18 years; AirCurve 10 device (ResMed); and ≥ 1 session with usage of ≥ 1 hour in the first 90 days. Key outcomes were mask leak and residual apnea-hypopnea index at different IPAP settings, adherence and therapy termination rates, and respiratory parameters at different minimum pressure support settings.

RESULTS

There were 63,996 patients included. Higher IPAP was associated with increased residual apnea-hypopnea index and mask leak but did not impact device usage per session (average > 6 h/day at all IPAP settings; 6.7 h/day at 95th percentile IPAP 25 cm H2O). There were no clinically relevant differences in respiratory rate, minute ventilation, leak, and residual apnea-hypopnea index across all possible minimum pressure support settings. Patients with a higher 95th percentile IPAP or with minimum pressure support of 3 cm H2O were most likely to remain on ASV therapy at 1 year.

CONCLUSIONS

Our findings showed robust levels of longer-term adherence to ASV therapy in a large group of real-world patients. There were no clinically important differences in respiratory parameters across a range of pressure and pressure support settings. Future work should focus on the different phenotypes of patients using ASV therapy.

CITATION

Malhotra A, Benjafield AV, Cistulli PA, et al. Characterizing respiratory parameters, settings, and adherence in real-world patients using adaptive servo ventilation therapy: big data analysis. J Clin Sleep Med. 2021;17(12):2355-2362.

Hidden Markov model segmentation to demarcate trajectories of residual apnoea-hypopnoea index in CPAP-treated sleep apnoea patients to personalize follow-up and prevent treatment failure

BACKGROUND

Continuous positive airway pressure (CPAP), the reference treatment for obstructive sleep apnoea (OSA), is used by millions of individuals worldwide with remote telemonitoring providing daily information on CPAP usage and efficacy, a currently underused resource. Here, we aimed to implement data science methods to provide tools for personalizing follow-up and preventing treatment failure.

METHODS

We analysed telemonitoring data from adults prescribed CPAP treatment. Our primary objective was to use Hidden Markov models (HMMs) to identify the underlying state of treatment efficacy and enable early detection of deterioration. Secondary goals were to identify clusters of rAHI trajectories which need distinct therapeutic strategies.

RESULTS

From telemonitoring records of 2860 CPAP-treated patients (age: 66.31 ± 12.92 years, 69.9% male), HMM estimated three states differing in variability within a given state and probability of shifting from one state to another. The daily inferred state informs on the need for a personalized action, while the sequence of states is a predictive indicator of treatment failure. Six clusters of rAHI trajectories were identified ranging from well-controlled patients (cluster 0: 669 (23%); mean rAHI 0.58 ± 0.59 events/h) to the most unstable (cluster 5: 470 (16%); mean rAHI 9.62 ± 5.62 events/h). CPAP adherence was 30 min higher in cluster 0 compared to clusters 4 and 5 (P value < 0.01).

CONCLUSION

This new approach based on HMM might constitute the backbone for deployment of patient-centred CPAP management improving the personalized interpretation of telemonitoring data, identifying individuals for targeted therapy and preventing treatment failure or abandonment.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13167-021-00264-z.

Sleep-disordered breathing and ventilatory chemosensitivity in first ischaemic stroke patients: a prospective cohort study

RATIONALE

Sleep-disordered breathing (SDB) is highly prevalent after stroke. The clinical and ventilatory chemosensitivity characteristics of SDB, namely obstructive, central and coexisting obstructive and central sleep apnoea (coexisting sleep apnoea) following stroke are poorly described.

OBJECTIVE

To determine the respective clinical and ventilatory chemosensitivity characteristics of SDB at least 3 months after a first ischaemic stroke.

METHODS

Cross-sectional analysis of a prospective, monocentric cohort conducted in a university hospital. 380 consecutive stroke or transient ischaemic attack patients were screened between December 2016 and December 2019.

MEASUREMENTS AND MAIN RESULTS

Full-night polysomnography, and hypercapnic ventilatory response were performed at a median (Q1; Q3) time from stroke onset of 134.5 (97.0; 227.3) days. 185 first-time stroke patients were included in the analysis. 94 (50.8%) patients presented no or mild SDB (Apnoea-Hypopnoea Index <15 events/hour of sleep) and 91 (49.2%) moderate to severe SDB, of which 52 (57.1%) presented obstructive sleep apnoea and 39 (42.9%) coexisting or central sleep apnoea. Obstructive sleep apnoea patients significantly differed regarding their clinical presentation from patients with no or mild SDB, whereas there was no difference with coexisting and central sleep apnoea patients. The latter presented a higher frequency of cerebellar lesions along with a heightened hypercapnic ventilatory response compared with no or mild SDB patients.

CONCLUSION

SDB in first-time stroke patients differ in their presentation by their respective clinical traits and ventilatory chemosensitivity characteristics. The heightened hypercapnic ventilatory response in coexisting and central sleep apnoea stroke patients may orientate them to specific ventilatory support.

Modeling patient-specific desaturation patterns in sleep apnea

OBJECTIVE

The physiological mechanisms involved in cardio-respiratory responses to sleep apnea events are not yet fully elucidated. A model-based approach is proposed to analyse the acute desaturation response to obstructive apneas.

METHODS

An integrated model of cardio-respiratory interactions was proposed and parameters were identified, using an evolutionary algorithm, on a database composed of 107 obstructive apneas acquired from 10 patients (HYPNOS clinical study). Unsupervised clustering was applied to the identified parameters in order to characterize the phenotype of each response to obstructive apneas.

RESULTS

A close match was observed between simulated oxygen saturation (SaO2) and experimental SaO2 in all identifications (median RMSE = 1.3892%). Two clusters of parameters, associated with different dynamics related to sleep apnea and periodic breathing were obtained.

CONCLUSION AND SIGNIFICANCE

The proposed patient and event-specific model-based analysis provides understanding on specific desaturation patterns, consequent to apnea events, with potential applications for personalized diagnosis and treatment.

The Importance of Mask Selection on Continuous Positive Airway Pressure Outcomes for Obstructive Sleep Apnea. An Official American Thoracic Society Workshop Report

Continuous positive airway pressure (CPAP) remains the major treatment option for obstructive sleep apnea (OSA). The American Thoracic Society organized a workshop to discuss the importance of mask selection for OSA treatment with CPAP. In this workshop report, we summarize available evidence about the breathing route during nasal and oronasal CPAP and the importance of nasal symptoms for CPAP outcomes. We explore the mechanisms of air leaks during CPAP treatment and possible alternatives for leak control. The impact of nasal and oronasal CPAP on adherence, residual apnea-hypopnea index, unintentional leaks, and pressure requirements are also compared. Finally, recommendations for patient and partner involvement in mask selection are presented, and future directions to promote personalized mask selection are discussed.

Optimal Noninvasive Medicare Access Promotion: Patients with Central Sleep Apnea A Technical Expert Panel Report from the American College of Chest Physicians, the American Association for Respiratory Care, the American Academy of Sleep Medicine, and the American Thoracic Society

This document summarizes suggestions of the central sleep apnea (CSA) technical expert panel (TEP) working group. This paper shares our vision for bringing the right device to the right patient at the right time. For patients with CSA, current coverage criteria do not align with guideline treatment recommendations. For example, continuous positive airway pressure (CPAP) and oxygen therapy are recommended but not covered for CSA. On the other hand, BPAP without a backup rate may be a covered therapy for OSA, but it may worsen CSA. Narrow coverage criteria that require near elimination of obstructive breathing events on CPAP or bilevel positive airway pressure in the spontaneous mode , even if at poorly tolerated pressure levels, may preclude therapy with BPAP with backup rate or adaptive servoventilation (ASV), even when those devices provide demonstrably better therapy. CSA is a dynamic disorder that may require different treatments over time, sometimes switching from one device to another, for example from BPAP with backup rate to an ASV with automatic end expiratory pressure adjustments, which may not be covered. To address these challenges we suggest several changes to the coverage determinations, including 1) a single simplified initial and continuing coverage definition of CSA that aligns with obstructive sleep apnea, 2) removal of hypoventilation terminology from coverage criteria for CSA, 3) all effective therapies for CSA should be covered, including oxygen and all PAP devices with or without backup rates or servo-mechanisms, and 4) patients shown to have a suboptimal response to one PAP device should be allowed to add oxygen or change to another PAP device with different capabilities if shown to be effective with testing.

Residual excessive daytime sleepiness in patients treated for obstructive sleep apnea: guidance for assessment, diagnosis, and management

Excessive daytime sleepiness (EDS) affects approximately half of patients with obstructive sleep apnea (OSA) and can persist in some despite normalization of breathing, oxygenation, and sleep quality with primary OSA therapy, such as continuous positive airway pressure (CPAP). EDS is often overlooked and under discussed in the primary care setting and in the follow-up of CPAP-treated patients due to difficult assessment of such a multi-dimensional symptom. This review aims to provide suggestions for procedures that can be implemented into routine clinical practice to identify, evaluate, and manage EDS in patients treated for OSA, including how to appropriately use various self-report and objective assessments along the clinical pathway and options for pharmacotherapy. In addition, examples of when it is appropriate to refer a patient to a sleep specialist for evaluation are discussed.

Treatment-emergent central sleep apnea associated with non-positive airway pressure therapies in obstructive sleep apnea patients: A systematic review

This systematic review summarizes the prevalence of treatment-emergent central sleep apnea (TECSA) occurring with therapies other than positive airway pressure (PAP) for the management of obstructive sleep apnea (OSA). We describe its natural course as well as the proposed underlying pathophysiological mechanisms and the clinical management of affected patients. A systematic search of PubMed, Embase, Web of science, and the Cochrane Library was performed until June 2020. Eighteen studies (n = 284 patients) were included. TECSA was observed in 31 patients with the use of four different medical devices (mandibular advancement device, hypoglossal nerve stimulation, tongue stabilizing device and nasal expiratory PAP) and after three different types of surgical treatments (tracheostomy, maxillofacial surgery and oro-nasal surgery). Due to the paucity of data available, it was not possible to establish a clear prevalence rate of TECSA for each alternative treatment. After the initiation of non-PAP treatments, a systematic reassessment of the treatment efficacy with follow-up sleep studies will be helpful to identify TECSA. A spontaneous resolution over time was described as well as a persistence of TECSA. In this case, treatment should focus on patients' specific underlying pathophysiology. Overall, the limited current literature suggests that this phenomenon is rare (<4%).

Treatment-emergent central sleep apnea: a unique sleep-disordered breathing

Treatment-emergent central sleep apnea (TECSA) is a specific form of sleep-disordered breathing, characterized by the emergence or persistence of central apneas during treatment for obstructive sleep apnea. The purpose of this review was to summarize the definition, epidemiology, potential mechanisms, clinical characteristics, and treatment of TECSA. We searched for relevant articles up to January 31, 2020, in the PubMed database. The prevalence of TECSA varied widely in different studies. The potential mechanisms leading to TECSA included ventilatory control instability, low arousal threshold, activation of lung stretch receptors, and prolonged circulation time. TECSA may be a self-limited disorder in some patients and could be resolved spontaneously over time with ongoing treatment of continuous positive airway pressure (CPAP). However, central apneas persist even with the regular CPAP therapy in some patients, and new treatment approaches such as adaptive servo-ventilation may be necessary. We concluded that several questions regarding TECSA remain, despite the findings of many studies, and it is necessary to carry out large surveys with basic scientific design and clinical trials for TECSA to clarify these irregularities. Further, it will be vital to evaluate the baseline demographic and polysomnographic data of TECSA patients more carefully and comprehensively.

Research Priorities for Patients with Heart Failure and Central Sleep Apnea. An Official American Thoracic Society Research Statement

Background: Central sleep apnea (CSA) is common among patients with heart failure and has been strongly linked to adverse outcomes. However, progress toward improving outcomes for such patients has been limited. The purpose of this official statement from the American Thoracic Society is to identify key areas to prioritize for future research regarding CSA in heart failure.

Methods: An international multidisciplinary group with expertise in sleep medicine, pulmonary medicine, heart failure, clinical research, and health outcomes was convened. The group met at the American Thoracic Society 2019 International Conference to determine research priority areas. A statement summarizing the findings of the group was subsequently authored using input from all members.

Results: The workgroup identified 11 specific research priorities in several key areas: 1) control of breathing and pathophysiology leading to CSA, 2) variability across individuals and over time, 3) techniques to examine CSA pathogenesis and outcomes, 4) impact of device and pharmacological treatment, and 5) implementing CSA treatment for all individuals

Conclusions: Advancing care for patients with CSA in the context of heart failure will require progress in the arenas of translational (basic through clinical), epidemiological, and patient-centered outcome research. Given the increasing prevalence of heart failure and its associated substantial burden to individuals, society, and the healthcare system, targeted research to improve knowledge of CSA pathogenesis and treatment is a priority.

Effect of healthcare benefits on short-term adherence of positive airway pressure therapy

PURPOSE

The objective of this study was to assess the impact of healthcare benefits on adherence to positive airway pressure (PAP) therapy in obstructive sleep apnea (OSA) patients.

METHODS

Medical records of OSA patients at the Veterans Health Service Medical Center were retrospectively reviewed. OSA patients were assigned to two groups as the date of prescribing PAP: after (=Group A) and before (=Group B) July 1, 2018 when PAP therapy starts to be included in healthcare insurance coverage for OSA patients in South Korea. PAP adherence was compared over a 3-month period between the two groups; subjective improvement after therapy was evaluated using the Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index scores. In addition, we evaluated a number of OSA patients who chose to start PAP therapy without healthcare benefit (from July 2018 to December 2018).

RESULTS

Each of the 50 patients in the Group A and B exhibited PAP adherence rates of 82% and 26%, respectively (P < .001). Age did not affect PAP adherence in the Group A. The mean apnea-hypopnea index (from 36.7 to 1.34, P < .001) and ESS (from 7.6 to 5.6, P = .004) scores of patients in the Group A had significantly improved within the first three months. Twenty-three (23 out of 334, 6.9%) OSA patients did not have any healthcare insurance, but they medically needed PAP therapy. However, only one of the 23 patients began PAP treatment.

CONCLUSION

Short-term PAP adherence significantly improved after PAP therapy was included in healthcare insurance coverage.

Apnea-hypopnea index supplied by CPAP devices: time for standardization?

BACKGROUND/OBJECTIVE

For obstructive sleep apnea (OSA) patients on continuous positive airway pressure (CPAP) treatment, the apnea-hypopnea index (AHI) is a key measure of treatment efficacy. However, the residual AHI is CPAP brand specific. Here, we studied changes in residual AHI in patients who used two different brands over their treatment history.

PATIENTS/METHODS

Using our CPAP telemonitoring database of 3102 patients, we compared the residual AHI of 69 patients before and after change in their CPAP device.

RESULTS

A paired Wilcoxon signed-rank test revealed a significant difference between brands in the reported AHI, which might be clinically misleading.

CONCLUSIONS

These findings suggest that physicians should be alerted to the differences between brands and learned societies should push for standardization of AHI reporting.

Sleep-Related Breathing Disorders: When CPAP Is Not Enough

Three decades ago, continuous positive airway pressure (CPAP) was introduced to treat obstructive sleep apnea (OSA). Shortly after, bilevel positive airway pressure devices (BPAP) that independently adjusted inspiratory and expiratory positive airway pressure were developed to treat complex sleep-related breathing disorders unresponsive to CPAP. Based on the bilevel positive airway pressure platform (hardware) governed by propriety algorithms (software), advanced modes of noninvasive ventilation (NIV) were developed to address complex cardiorespiratory pathophysiology beyond OSA. This review summarizes key aspects of different bilevel PAP therapies (BPAP with/without backup rate, adaptive servoventilation, and volume-assured pressure support) to treat common sleep-related hypoventilation disorders, treatment-emergent central sleep apnea, and central sleep apnea syndromes.

Patterns of adaptive servo-ventilation settings in a real-life multicenter study: pay attention to volume! : Adaptive servo-ventilation settings in real-life conditions

Backgrounds

To explain the excess cardiovascular mortality observed in the SERVE-HF study, it was hypothesized that the high-pressure ASV default settings used lead to inappropriate ventilation, cascading negative consequences (i.e. not only pro-arrythmogenic effects through metabolic/electrolyte abnormalities, but also lower cardiac output). The aims of this study are: i) to describe ASV-settings for long-term ASV-populations in real-life conditions; ii) to describe the associated minute-ventilations (MV) and therapeutic pressures for servo-controlled-flow versus servo-controlled-volume devices (ASV-F Philips®-devices versus ASV-V ResMed®-devices).

Methods

The OTRLASV-study is a cross-sectional, 5-centre study including patients who underwent ASV-treatment for at least 1 year. The eight participating clinicians were free to adjust ASV settings, which were compared among i) initial diagnosed sleep-disordered-breathing (SBD) groups (Obstructive-Sleep-Apnea (OSA), Central-Sleep-Apnea (CSA), Treatment-Emergent-Central-Sleep-Apnea (TECSA)), and ii) unsupervised groups (k-means clusters). To generate these clusters, baseline and follow-up variables were used (age, sex, body mass index (BMI), initial diagnosed Obstructive-Apnea-Index, initial diagnosed Central-Apnea-Index, Continuous-Positive-Airway-Pressure used before ASV treatment, presence of cardiopathy, and presence of a reduced left-ventricular-ejection-fraction (LVEF)). ASV-data were collected using the manufacturer’s software for 6 months.

Results

One hundred seventy-seven patients (87.57% male) were analysed with a median (IQ_25–75) initial Apnea-Hypopnea-Index of 50 (38–62)/h, an ASV-treatment duration of 2.88 (1.76–4.96) years, 61.58% treated with an ASV-V. SDB groups did not differ in ASV settings, MV or therapeutic pressures. In contrast, the five generated k-means clusters did (generally described as follows: (C1) male-TECSA-cardiopathy, (C2) male-mostly-CSA-cardiopathy, (C3) male-mostly-TECSA-no cardiopathy, (C4) female-mostly-elevated BMI-TECSA-cardiopathy, (C5) male-mostly-OSA-low-LVEF). Of note, the male-mostly-OSA-low-LVEF-cluster-5 had significantly lower fixed end-expiratory-airway-pressure (EPAP) settings versus C1 (p = 0.029) and C4 (p = 0.007). Auto-EPAP usage was higher in the male-mostly-TECSA-no cardiopathy-cluster-3 versus C1 (p = 0.006) and C2 (p < 0.001). MV differences between ASV-F (p = 0.002) and ASV-V (p < 0.001) were not homogenously distributed across clusters, suggesting specific cluster and ASV-algorithm interactions. Individual ASV-data suggest that the hyperventilation risk is not related to the cluster nor the ASV-monitoring type.

Conclusions

Real-life ASV settings are associated with combinations of baseline and follow-up variables wherein cardiological variables remain clinically meaningful. At the patient level, a hyperventilation risk exists regardless of cluster or ASV-monitoring type, spotlighting a future role of MV-telemonitoring in the interest of patient-safety.

Trial registration

The OTRLASV study was registered on ClinicalTrials.gov (Identifier: NCT02429986). 1 April 2015.

Adaptive Servo-Ventilation: A Comprehensive Descriptive Study in the Geneva Lake Area

Background: Use of adaptive servo-ventilation (ASV) has been questioned in patients with central sleep apnea (CSA) and chronic heart failure (CHF). This study aims to detail the present use of ASV in clinical practice.

Methods: Descriptive, cross-sectional, multicentric study of patients undergoing long term (≥3 months) ASV in the Cantons of Geneva or Vaud (1,288,378 inhabitants) followed by public or private hospitals, private practitioners and/or home care providers.

Results: Patients included (458) were mostly male (392; 85.6%), overweight [BMI (median, IQR): 29 kg/m² (26; 33)], comorbid, with a median age of 71 years (59–77); 84% had been treated by CPAP before starting ASV. Indications for ASV were: emergent sleep apnea (ESA; 337; 73.6%), central sleep apnea (CSA; 108; 23.6%), obstructive sleep apnea (7; 1.5%), and overlap syndrome (6; 1.3%). Origin of CSA was cardiac (n = 30), neurological (n = 26), idiopathic (n = 28), or drug-related (n = 22). Among CSA cases, 60 (56%) patients had an echocardiography within the preceding 12 months; median left ventricular ejection fraction (LVEF) was 62.5% (54–65); 11 (18%) had a LVEF ≤45%. Average daily use of ASV was [mean (SD)] 368 (140) min; 13% used their device <3:30 h. Based on ventilator software, apnea-hypopnea index was normalized in 94% of subjects with data available (94% of 428).

Conclusions: Use of ASV has evolved from its original indication (CSA in CHF) to a heterogeneous predominantly male, aged, comorbid, and overweight population with mainly ESA or CSA. CSA in CHF represented only 6.5% of this population. Compliance and correction of respiratory events were satisfactory.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT04054570.

Update on Persistent Excessive Daytime Sleepiness in OSA

OSA is a highly prevalent sleep disorder, and subjective excessive daytime sleepiness (EDS) is the cardinal symptom for which many individuals seek medical advice. Positive airway pressure (PAP) devices, first-line treatment for OSA, eliminates EDS in most patients. However, a subset of patients suffers from persistent EDS despite adherence to therapy. Multiple conditions, some reversible, could account for the residual sleepiness and need to be explored, requiring detailed history, review of PAP data from the smart card, and sometimes additional testing. When all known causes of EDS are excluded, in adequately treated subjects, the purported mechanisms could relate to long-term exposure to the OSA-related sleep fragmentation, sleep deprivation, and hypoxic injury to the arousal system, shifts in melatonin secretion, or altered microbiome. Independent of the mechanism, in well-treated OSA, pharmacological therapy with approved drugs can be considered. Modafinil is commonly prescribed to combat residual EDS, but more recently two drugs, solriamfetol, a dual dopamine-norepinephrine reuptake inhibitor, and pitolisant, a histamine H3 receptor inverse agonist, were approved for EDS. Solriamfetol has undergone randomized controlled trials for treatment of EDS associated with both OSA and narcolepsy, exhibiting robust efficacy. Solriamfetol is renally excreted, with no known drug interactions. Pitolisant, which is nonscheduled, has undergone multiple RCTs in narcolepsy, showing improvement in subjective and objective EDS and one OSA trial showing improvement in subjective EDS.

The use and effectiveness of adaptive servo ventilation in central sleep apnea: a study of consecutive sleep clinic patients

The use of adaptive servo ventilation to treat central sleep apnea in the clinical setting is incompletely understood and could be under-utilized. We reviewed our experience of adaptive servo ventilation use in patients with central sleep apnea. This study shows the effectiveness of adaptive servo ventilation in treating patients with central sleep apnea, irrespective of a predisposing factor, as assessed during a 4-week treatment trial. Results show that adaptive servo ventilation was effective and superior to continuous positive airway pressure in controlling central sleep apnea and improving symptoms. Only a small proportion of these patients had comorbid heart failure. Early treatment with adaptive servo ventilation may improve long-term adherence to therapy. These findings highlight the utility of adaptive servo ventilation in the management of central sleep apnea.

Phenotypic Subtypes of OSA: A Challenge and Opportunity for Precision Medicine

Current strategies for the management of OSA reflect a one-size-fits-all approach. Diagnosis and severity of OSA are based on the apnea-hypopnea index and treatment initiated with CPAP, followed by trials of alternatives (eg, oral appliances) if CPAP "fails." This approach does not consider the heterogeneity of individuals with OSA, reflected by varying risk factors, pathophysiological causes, clinical manifestations, and consequences. Recently, studies using analytic approaches such as cluster analysis have taken advantage of this heterogeneity to identify OSA phenotypes, or subtypes of patients with unique characteristics, that may enable more personalized approaches to prognostication and treatment. Examples include symptom-based subtypes such as "excessively sleepy" and "disturbed sleep" with differing impact of CPAP on symptoms and health-related quality of life. Polysomnographic subtypes, distinguished by respiratory event association with hypoxemia, arousals, or both, exhibit varying risks of cardiovascular disease and response to therapy. This review summarizes the findings from recent cluster analysis studies in sleep apnea and synthesizes common themes to describe the potential role (and limitations) of phenotypic subtypes in precision medicine for OSA. It also highlights future directions, including linking of phenotypes to clinically relevant outcomes, rigorous and transparent assessment of phenotype reproducibility, and need for tools that categorize patients into subtypes, to prospectively validate phenotype-based prognostication and treatment approaches. Finally, we highlight the critical need to include women and more racially/ethnically diverse populations in this area of research if we are to leverage the heterogeneity of OSA to improve patient lives.

[What prospects for the sleep apnea syndrome and connected health?]

Connected health is a growing field and can be viewed from different perspectives, particularly in sleep apnea syndrome. The purpose of this review is to show how all these aspects of connected health are already used in the management of sleep apnea syndrome (SAS) and its comorbidities. First, it can give patients a better understanding and a better assessment of their health. It also facilitates their healthcare by allowing them a greater role in their care pathway. For healthcare providers, connected health tools make it possible to set up new procedures for diagnosing and monitoring ambulatory patients, and for the making of joint decisions by health professionals and patients. Finally, for researchers, e-health generates massive amounts of data, thus facilitating the acquisition of knowledge in real life situations and the development of new methodologies for clinical studies that are faster, less expensive and just as reliable. All these considerations are already applicable in the field of sleep apnea, both for proposed treatments and for comorbidities management and for the patient's involvement in his/her care pathway.

What is the remaining status of adaptive servo-ventilation? The results of a real-life multicenter study (OTRLASV-study) : Adaptive servo-ventilation in real-life conditions

BACKGROUNDS

As a consequence of the increased mortality observed in the SERVE-HF study, many questions concerning the safety and rational use of ASV in other indications emerged. The aim of this study was to describe the clinical characteristics of ASV-treated patients in real-life conditions.

METHODS

The OTRLASV-study is a prospective, 5-centre study including patients who underwent ASV-treatment for at least 1 year. Patients were consecutively included in the study during the annual visit imposed for ASV-reimbursement renewal.

RESULTS

177/214 patients were analysed (87.57% male) with a median (IQ25-75) age of 71 (65-77) years, an ASV-treatment duration of 2.88 (1.76-4.96) years, an ASV-usage of 6.52 (5.13-7.65) hours/day, and 54.8% were previously treated via continuous positive airway pressure (CPAP). The median Epworth Scale Score decreased from 10 (6-13.5) to 6 (3-9) (p < 0.001) with ASV-therapy, the apnea-hypopnea-index decreased from 50 (38-62)/h to a residual device index of 1.9 (0.7-3.8)/h (p < 0.001). The majority of patients were classified in a Central-Sleep-Apnea group (CSA; 59.3%), whereas the remaining are divided into an Obstructive-Sleep-Apnea group (OSA; 20.3%) and a Treatment-Emergent-Central-Sleep-Apnea group (TECSA; 20.3%). The Left Ventricular Ejection Fraction (LVEF) was > 45% in 92.7% of patients. Associated comorbidities/etiologies were cardiac in nature for 75.7% of patients (neurological for 12.4%, renal for 4.5%, opioid-treatment for 3.4%). 9.6% had idiopathic central-sleep-apnea. 6.2% of the patients were hospitalized the year preceding the study for cardiological reasons. In the 6 months preceding inclusion, night monitoring (i.e. polygraphy or oximetry during ASV usage) was performed in 34.4% of patients, 25.9% of whom required a subsequent setting change. According to multivariable, logistic regression, the variables that were independently associated with poor adherence (ASV-usage ≤4 h in duration) were TECSA group versus CSA group (p = 0.010), a higher Epworth score (p = 0.019) and lack of a night monitoring in the last 6 months (p < 0.05).

CONCLUSIONS

In real-life conditions, ASV-treatment is often associated with high cardiac comorbidities and high compliance. Future research should assess how regular night monitoring may optimize devices settings and patient management.

TRIAL REGISTRATION

The OTRLASV study is registered on ClinicalTrials.gov (Identifier: NCT02429986 ) on 1 April 2015.

Redesigning Care for OSA

Constrained by a limited supply of specialized personnel, health systems face a challenge in caring for the large number of patients with OSA. The complexity of this challenge is heightened by the varied clinical presentations of OSA and the diversity of treatment approaches. Innovations such as simplified home-based care models and the incorporation of nonspecialist providers have shown promise in the management of uncomplicated patients, producing comparable outcomes to the resource-intensive traditional approach. However, it is unclear if these innovations can meet the needs of all patients with OSA, including those with mild disease, atypical presentations, and certain comorbid medical and mental health conditions. This review discusses the diversity of needs in OSA care, the evidence base behind recent care innovations, and the potential limitations of each innovation in meeting the diversity of care needs. We propose how these innovations can fit within the stepped care and hub and spoke models in a way that addresses the full spectrum of OSA, and we discuss future research directions to assess the deployment of these innovations.

More Than the Sum of the Respiratory Events: Personalized Medicine Approaches for Obstructive Sleep Apnea

Traditionally, the presence and severity of obstructive sleep apnea (OSA) have been defined by the apnea-hypopnea index (AHI). Continuous positive airway pressure is generally first-line therapy despite low adherence, because it reliably reduces the AHI when used, and the response to other therapies is variable. However, there is growing appreciation that the underlying etiology (i.e., endotype) and clinical manifestation (i.e., phenotype) of OSA in an individual are not well described by the AHI. We define and review the important progress made in understanding and measuring physiological mechanisms (or endotypes) that help define subtypes of OSA and identify the potential use of genetics to further refine disease classification. This more detailed understanding of OSA pathogenesis should influence clinical treatment decisions as well as help inform research priorities and clinical study design. In short, treatments could be individualized on the basis of the underlying cause of OSA; patients could better understand which symptoms and outcomes will respond to OSA treatment and by how much; and researchers could select populations most likely to benefit from specific treatment approaches for OSA.

Prospective Randomized Controlled Trial on the Efficacy of Continuous Positive Airway Pressure and Adaptive Servo-Ventilation in the Treatment of Chronic Complex Insomnia

BACKGROUND

Complex insomnia, the comorbidity of chronic insomnia and obstructive sleep apnea (OSA), is a common sleep disorder, but the OSA component, whether presenting overtly or covertly, often goes unsuspected and undiagnosed due to a low index of suspicion. Among complex insomniacs, preliminary evidence demonstrates standard CPAP decreases insomnia severity. However, CPAP causes expiratory pressure intolerance or iatrogenic central apneas that may diminish its use. An advanced PAP mode-adaptive servo-ventilation (ASV)-may alleviate CPAP side-effects and yield superior outcomes.

METHODS

In a single-site protocol investigating covert complex insomnia (ClinicalTrials.gov identifier: NCT02365064), a low index of suspicion for this comorbidity was confirmed by exclusion of 455 of 660 eligible patients who presented during the study period with overt OSA signs and symptoms. Ultimately, stringent inclusion/exclusion criteria to test efficacy yielded 40 adult, covert complex insomnia patients [average Insomnia Severity Index (ISI) moderate-severe 19.30 (95% CI 18.42-20.17)] who reported no definitive OSA symptoms or risks and who failed behavioral or drug therapy for an average of one decade. All 40 were diagnosed with OSA and randomized (using block randomization) to a single-blind, prospective protocol, comparing CPAP (n = 21) and ASV (n = 19). Three successive PAP titrations fine-tuned pressure settings, facilitated greater PAP use, and collected objective sleep and breathing data. Patients received 14 weeks of treatment including intensive biweekly coaching and follow-up to foster regular PAP use in order to accurately measure efficaciousness. Primary outcomes measured insomnia severity and sleep quality. Secondary outcomes measured daytime impact: OSA-induced impairment, fatigue severity, insomnia impairment, and quality of life. Performance on these seven variables was assessed using repeated measures ANCOVA to account for the multiple biweekly time points.

FINDINGS

At intake, OSA diagnosis and OSA as a cause for insomnia were denied by all 40 patients, yet PAP significantly decreased insomnia severity scores (p = 0.021 in the primary ANCOVA analysis). To quantify effect sizes, mean intake vs endpoint analysis was conducted with ASV yielding nearly twice the effects of CPAP [- 13.2 (10.7-15.7), Hedges' g = 2.50 vs - 9.3 (6.3-12.3), g = 1.39], and between mode effect size was in the medium-large range 0.65. Clinically, ASV led to remission (ISI < 8) in 68% of cases compared to 24% on CPAP [Fisher's exact p = 0.010]. Two sleep quality measures in the ANCOVA analysis again demonstrated superior significant effects for ASV compared to CPAP (both p < 0.03), and pre- and post-analysis demonstrated substantial effects for both scales [ASV (g = 1.42; g = 1.81) over CPAP (g = 1.04; g = 0.75)] with medium size effects between modes (0.54, 0.51). Measures of impairment, residual objective sleep breathing events, and normalized breathing periods consistently demonstrated larger beneficial effects for ASV over CPAP.

INTERPRETATION

PAP therapy was highly efficacious in decreasing insomnia severity in chronic insomnia patients with previously undiagnosed co-morbid OSA. ASV proved superior to CPAP in this first efficacy trial to compare advanced to traditional PAP modes in complex insomnia. Future research must determine the following: pathophysiological mechanisms to explain how OSA causes chronic insomnia; general population prevalence of this comorbidity; and, cost-effectiveness of ASV therapy in complex insomnia. Last, efforts to raise awareness of complex insomnia are urgently needed as patients and providers appear to disregard both overt and covert signs and symptoms of OSA in the assessment of chronic insomnia.