Obstructive sleep apnea and oxygen therapy: a systematic review of the literature and meta-analysis

Chronic obstructive pulmonary disease and obstructive sleep apnea overlap: who to treat and how?

INTRODUCTION

The co-existence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA), or the overlap syndrome, is common and associated with a distinct pattern of nocturnal hypoxemia and worse clinical outcomes than either disease alone. Consequently, identifying who and how to treat these patients is essential.

AREAS COVERED

Treatment is recommended in all patients with OSA and symptoms or systemic hypertension, but determining symptoms attributable to OSA can be challenging in patients with COPD. Treatment should be considered in asymptomatic patients with moderate to severe OSA and COPD with pulmonary hypertension and comorbid cardiovascular and cerebrovascular disease, especially if marked hypoxic burden. CPAP is effective, but in patients with the overlap syndrome and daytime hypercapnia, high-intensity noninvasive ventilation aiming to lower PaCO2 may have additional benefits. Additionally, in those with severe resting daytime hypoxemia, supplemental oxygen improves survival and should be added to positive airway pressure. The role of alternative non-positive airway pressure therapies in the overlap syndrome needs further study.

EXPERT OPINION

Both COPD and OSA are heterogeneous disorders with a wide range of disease severity and further research is needed to better characterize and prognosticate patients with the overlap syndrome to personalize treatment.

Treatment of obstructive sleep apnea relieves stuttering priapism in patient with sickle cell disease: a case report

Background

Stuttering priapism is recurrent, self-limited episodes of sustained penile erection and is common in patients with sickle cell disease (SCD). Prevention of stuttering priapism is important to avoid progression to episodes of ischemic priapism which can cause erectile dysfunction. Priapism has been shown to be associated with increased nocturnal hypoxemia in patients with SCD.

Case Description

A 43-year-old male with nocturnal episodes of stuttering priapism that was refractory to treatment with multiple medications was found to have obstructive sleep apnea (OSA). Following treatment of this condition with a continuous positive airway pressure (CPAP), the patient had immediate symptom relief and has had three months without an episode of priapism.

Conclusions

OSA should be considered as an underlying cause of nocturnal stuttering priapism in patients with SCD, particularly in patients who present with stuttering priapism later in life or patients who present strictly with nocturnal episodes. Appropriate management of OSA can significantly decrease the incidence of stuttering priapism in patients with SCD.

Obstructive Sleep Apnea and Pulmonary Hypertension: A Chicken-and-Egg Relationship

Obstructive sleep apnea (OSA) is characterized by repeated episodes of upper airway obstruction during sleep, and it is closely linked to several cardiovascular issues due to intermittent hypoxia, nocturnal hypoxemia, and disrupted sleep patterns. Pulmonary hypertension (PH), identified by elevated pulmonary arterial pressure, shares a complex interplay with OSA, contributing to cardiovascular complications and morbidity. The prevalence of OSA is alarmingly high, with studies indicating rates of 20-30% in males and 10-15% in females, escalating significantly with age and obesity. OSA's impact on cardiovascular health is profound, particularly in exacerbating conditions like systemic hypertension and heart failure. The pivotal role of hypoxemia increases intrathoracic pressure, inflammation, and autonomic nervous system dysregulation in this interplay, which all contribute to PH's pathogenesis. The prevalence of PH among OSA patients varies widely, with studies reporting rates from 15% to 80%, highlighting the variability in diagnostic criteria and methodologies. Conversely, OSA prevalence among PH patients also remains high, often exceeding 25%, stressing the need for careful screening and diagnosis. Treatment strategies like continuous positive airway pressure (CPAP) therapy show promise in mitigating PH progression in OSA patients. However, this review underscores the need for further research into long-term outcomes and the efficacy of these treatments. This review provides comprehensive insights into the epidemiology, pathophysiology, and treatment of the intricate interplay between OSA and PH, calling for integrated, personalized approaches in diagnosis and management. The future landscape of OSA and PH management hinges on continued research, technological advancements, and a holistic approach to improving patient outcomes.

Treatment of Sleep Apnea and Reduction in Blood Pressure: The Role of Heart Rate Response and Hypoxic Burden

BACKGROUND

Obstructive sleep apnea is associated with increased blood pressure (BP). Obstructive sleep apnea treatment reduces BP with substantial variability, not explained by the apnea-hypopnea index, partly due to inadequate characterization of obstructive sleep apnea's physiological consequences, such as oxygen desaturation, cardiac autonomic response, and suboptimal treatment efficacy. We sought to examine whether a high baseline heart rate response (ΔHR), a marker of high cardiovascular risk in obstructive sleep apnea, predicts a larger reduction in post-treatment systolic BP (SBP). Furthermore, we aimed to assess the extent to which a reduction in SBP is explained by a treatment-related reduction in hypoxic burden (HB).

METHODS

ΔHR and HB were measured from pretreatment and posttreatment polygraphy, followed by a 24-hour BP assessment in 168 participants treated with continuous positive airway pressure or nocturnal supplemental oxygen from the HeartBEAT study (Heart Biomarker Evaluation in Apnea Treatment). Multiple linear regression models assessed whether high versus mid (reference) ΔHR predicted a larger reduction in SBP (primary outcome) and whether there was an association between treatment-related reductions in SBP and HB.

RESULTS

A high versus mid ΔHR predicted improvement in SBP (adjusted estimate, 5.8 [95% CI, 1.0-10.5] mm Hg). Independently, a greater treatment-related reduction in HB was significantly associated with larger reductions in SBP (4.2 [95% CI, 0.9-7.5] mm Hg per 2 SD treatment-related reduction in HB). Participants with substantial versus minimal treatment-related reductions in HB had a 6.5 (95% CI, 2.5-10.4) mm Hg drop in SBP.

CONCLUSIONS

A high ΔHR predicted a more favorable BP response to therapy. Furthermore, the magnitude of the reduction in BP was partly explained by a greater reduction in HB.

Increased Flow Limitation During Sleep Is Associated With Increased Psychomotor Vigilance Task Lapses in Individuals With Suspected OSA

BACKGROUND

Impaired daytime vigilance is an important consequence of OSA, but several studies have reported no association between objective measurements of vigilance and the apnea-hypopnea index (AHI). Notably, the AHI does not quantify the degree of flow limitation, that is, the extent to which ventilation fails to meet intended ventilation (ventilatory drive).

RESEARCH QUESTION

Is flow limitation during sleep associated with daytime vigilance in OSA?

STUDY DESIGN AND METHODS

Nine hundred ninety-eight participants with suspected OSA completed a 10-min psychomotor vigilance task (PVT) before same-night in-laboratory polysomnography. Flow limitation frequency (percent of flow-limited breaths) during sleep was quantified using airflow shapes (eg, fluttering and scooping) from nasal pressure airflow. Multivariable regression assessed the association between flow limitation frequency and the number of lapses (response times > 500 ms, primary outcome), adjusting for age, sex, BMI, total sleep time, depression, and smoking status.

RESULTS

Increased flow limitation frequency was associated with decreased vigilance: a 1-SD (35.3%) increase was associated with 2.1 additional PVT lapses (95% CI, 0.7-3.7; P = .003). This magnitude was similar to that for age, where a 1-SD increase (13.5 years) was associated with 1.9 additional lapses. Results were similar after adjusting for AHI, hypoxemia severity, and arousal severity. The AHI was not associated with PVT lapses (P = .20). In secondary exploratory analysis, flow limitation frequency was associated with mean response speed (P = .012), median response time (P = .029), fastest 10% response time (P = .041), slowest 10% response time (P = .018), and slowest 10% response speed (P = .005).

INTERPRETATION

Increased flow limitation during sleep was associated with decreased daytime vigilance in individuals with suspected OSA, independent of the AHI. Flow limitation may complement standard clinical metrics in identifying individuals whose vigilance impairment most likely is explained by OSA.

Nocturnal oxygen therapy in obstructive sleep apnoea: a systematic review and meta-analysis

Obstructive sleep apnoea is characterised by recurrent reduction of airflow during sleep leading to intermittent hypoxia. Continuous positive airway pressure is the first-line treatment but is limited by poor adherence. Nocturnal oxygen therapy may be an alternative treatment for obstructive sleep apnoea but its effects remain unclear. This meta-analysis evaluates the effects of nocturnal oxygen therapy on both obstructive sleep apnoea severity and blood pressure.A literature search was performed based on the Preferred Reporting Items for Systematic Review and Meta-analysis guidelines. Peer-reviewed, randomised studies that compared the effect of nocturnal oxygen therapy to sham in obstructive sleep apnoea patients were included. The main outcomes were the apnoea-hypopnoea index and systolic and diastolic blood pressure.The search strategy yielded 1295 citations. Nine studies with 502 participants were included. When nocturnal oxygen therapy was compared to sham/air, it significantly reduced the apnoea-hypopnoea index (mean difference (MD) -15.17 events·h-1, 95% CI -19.95- -10.38 events·h-1, p<0.00001). Nocturnal oxygen therapy had no significant effect on blood pressure at follow-up without adjustment for baseline values, but did, where available, significantly attenuate the change in blood pressure from baseline to follow-up for both systolic blood pressure (MD -2.79 mmHg, 95% CI -5.45- -0.14 mmHg, p=0.040) and diastolic blood pressure (MD -2.20 mmHg, 95% CI -3.83- -0.57 mmHg, p=0.008).Nocturnal oxygen therapy reduced the apnoea-hypopnoea index severity and the change in (but not absolute) systolic and diastolic blood pressure, compared to sham. This suggests that nocturnal oxygen therapy may be a treatment option for obstructive sleep apnoea. Further studies with longer-term follow-up and standardised measurements are needed.

Clinical, polysomnographic, and heart rate variability in highland obstructive sleep apnea patients responding to one-night nocturnal oxygen supplementation: A post-hoc analysis from a randomized, crossover trial

OBJECTIVE

/Background: This study aimed to explore the clinical, polysomnographic, and heart rate variability (HRV) characteristics of highland obstructive sleep apnea (OSA) patients receiving one-night nocturnal oxygen supplementation (NOS) and to identify factors predicting response.

PATIENTS/METHODS

Thirty-four highland OSA patients living in Shangri-La were randomly assigned to receive NOS and sham oxygen in a randomized, placebo-controlled, crossover trial. Clinical assessments, polysomnography, and HRV were measured. A responder was defined as a ≥50% reduction in apnea-hypopnea index (AHI) with NOS compared with sham oxygen.

RESULTS

Eighteen participants responded and 16 did not respond, with a median (interquartile range [IQR]) age of 46.5 (36.5-53.0) and 48.0 (44.3-53.3) years, respectively. The median treatment effect (95% CI) on total AHI was -23.2/h (-30.0 to -17.5) and -12.0/h (-16.6 to -7.6) in responders and non-responders (p = 0.004), with similar effects on oxygen desaturation index. The mean OAH duration was prolonged by 7 s in responders together with improved sleep quality and daytime blood pressure. The mean OAH duration at baseline predicted responses to NOS with a sensitivity and specificity of 88.9% and 68.7% (AUC 0.809) at a cut-off point of 24.9 s. Changes in HRV parameters were negatively correlated with changes in mean oxygen saturation and daytime systolic blood pressure only in responders.

CONCLUSIONS

NOS significantly improved OSA severity and clinical outcomes in responders, which was related to improvements in parasympathetic activity. Highlanders with shorter mean OAH may be suitable candidates for NOS. These findings provide new information about tailored treatment strategies for highland OSA patients.

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.

Sleep Disturbances and Disorders in Patients with Knee Osteoarthritis and Total Knee Arthroplasty

➤

There is increasing evidence that patient-reported outcomes following total knee arthroplasty (TKA) are associated with psychosocial factors and pain catastrophizing. Sleep disturbance, pain, and mental health have a complex interaction, which, if unrecognized, can be associated with impaired patient-reported outcomes and dissatisfaction following TKA.

➤

The gold standard of objective sleep assessment is polysomnography, which is not feasible to use routinely for TKA patients. Wearable devices are a validated and less costly alternative.

➤

Subjective sleep measures, such as the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, or Patient-Reported Outcomes Measurement Information System (PROMIS) computerized adaptive test sleep domains, are simple to administer and provide additional insight into sleep disturbance. Although objective and subjective measures do not correlate precisely, they can be informative together.

➤

Sleep disturbances in the elderly population are common and multifactorial in etiology, stemming from the interplay of sleep disorders, medication side effects, and pain. Commonly prescribed medications following TKA as well as postoperative pain can exacerbate underlying sleep disturbances.

➤

Obstructive sleep apnea (OSA) is prevalent in patients seeking TKA. In the setting of OSA, postoperative opioids can cause respiratory depression, resulting in consequences as severe as death. A standardized multimodal pain protocol including anti-inflammatories and gamma-aminobutyric acid (GABA) analogues may allow for decreased reliance on opioids for pain control.

➤

Surgeons should reassure patients that postoperative sleep disturbance is common and transient, collaborate with the patient's primary care doctor to address sleep disturbance, and avoid prescription of pharmaceutical sleep aids.

2022 Brazilian Thoracic Association recommendations for long-term home oxygen therapy

Some chronic respiratory diseases can cause hypoxemia and, in such cases, long-term home oxygen therapy (LTOT) is indicated as a treatment option primarily to improve patient quality of life and life expectancy. Home oxygen has been used for more than 70 years, and support for LTOT is based on two studies from the 1980s that demonstrated that oxygen use improves survival in patients with COPD. There is evidence that LTOT has other beneficial effects such as improved cognitive function, improved exercise capacity, and reduced hospitalizations. LTOT is indicated in other respiratory diseases that cause hypoxemia, on the basis of the same criteria as those used for COPD. There has been an increase in the use of LTOT, probably because of increased life expectancy and a higher prevalence of chronic respiratory diseases, as well as greater availability of LTOT in the health care system. The first Brazilian Thoracic Association consensus statement on LTOT was published in 2000. Twenty-two years la-ter, we present this updated version. This document is a nonsystematic review of the literature, conducted by pulmonologists who evaluated scientific evidence and international guidelines on LTOT in the various diseases that cause hypoxemia and in specific situations (i.e., exercise, sleep, and air travel). These recommendations, produced with a view to clinical practice, contain several charts with information on indications for LTOT, oxygen sources, accessories, strategies for improved efficiency and effectiveness, and recommendations for the safe use of LTOT, as well as a LTOT prescribing model.

Characteristics of Patients with Unrecognized Sleep Apnea Requiring Postoperative Oxygen Therapy

Surgical patients with obstructive sleep apnea (OSA) have increased risk of perioperative complications. The primary objective is to determine the characteristics of surgical patients with unrecognized OSA requiring oxygen therapy for postoperative hypoxemia. The secondary objective is to investigate the characteristics of patients who were responsive to oxygen therapy. This was a post-hoc multicenter study involving patients with cardiovascular risk factors undergoing major non-cardiac surgery. Patients ≥45 years old underwent Type 3 sleep apnea testing and nocturnal oximetry preoperatively. Responders to oxygen therapy were defined as individuals with ≥50% reduction in oxygen desaturation index (ODI) on postoperative night 1 versus preoperative ODI. In total, 624 out of 823 patients with unrecognized OSA required oxygen therapy. These were mostly males, had larger neck circumferences, higher Revised Cardiac Risk Indices, higher STOP-Bang scores, and higher ASA physical status, undergoing intraperitoneal or vascular surgery. Multivariable regression analysis showed that the preoperative longer cumulative time SpO2 < 90% or CT90% (adjusted p = 0.03), and lower average overnight SpO2 (adjusted p < 0.001), were independently associated with patients requiring oxygen therapy. Seventy percent of patients were responders to oxygen therapy with ≥50% ODI reduction. Preoperative ODI (19.0 ± 12.9 vs. 14.1 ± 11.4 events/h, p < 0.001), CT90% (42.3 ± 66.2 vs. 31.1 ± 57.0 min, p = 0.038), and CT80% (7.1 ± 22.6 vs. 3.6 ± 8.7 min, p = 0.007) were significantly higher in the responder than the non-responder. Patients with unrecognized OSA requiring postoperative oxygen therapy were males with larger neck circumferences and higher STOP-Bang scores. Those responding to oxygen therapy were likely to have severe OSA and worse preoperative nocturnal hypoxemia. Preoperative overnight oximetry parameters may help in stratifying patients.

Combination therapy of high-flow nasal cannula and upper body elevation for postoperative sleep disordered breathing; randomized cross-over trial

BACKGROUND

Low acceptance rate of continuous positive airway pressure therapy in postoperative patients with untreated obstructive sleep apnea (OSA) indicates the necessity for development of an alternative postoperative airway management strategy. We considered whether the combination of high-flow nasal cannula and upper body elevation could improve postoperative OSA.

METHODS

This non-blinded randomized crossover study performed at a single university hospital investigated the effect on a modified apnea hypopnea index, based exclusively on the airflow signal without arterial oxygen saturation criteria (flow-based apnea hypopnea index, primary outcome), of high-flow nasal cannula (20 liter.minute-1 with 40% oxygen concentration) with and without upper body elevation in patients with moderate to severe OSA. Preoperative sleep studies were performed at home (control, no head-of-bed elevation) and in hospital (30-degree head-of-bed elevation). On the first and second postoperative nights, high-flow nasal cannula was applied with or without 30-degree head-of-bed elevation, assigned in random order to 23 eligible participants.

RESULTS

Twenty-two out of the 23 (96%) accepted high-flow nasal cannula. Four participants resigned from the study. Control flow-based apnea hypopnea index (mean±SD: 59.6 ± 12.0 events.hour-1, n=19) was reduced by 14.7 (95% CI: 5.5 to 30.0) events.hour-1 with head-of-bed elevation alone (p=0.002), 10.9 (1.2 to 20.6) events.hour-1 with high-flow nasal cannula alone (p=0.028), and 22.5 (13.1 to 31.9) events.hour-1 with combined head-of-bed elevation and high-flow nasal cannula (p<0.001). Compared to sole high-flow nasal cannula, additional intervention with head-of-bed elevation significantly decreased flow-based apnea hypopnea index by 11.5 events.hour-1 (1.7 to 21.4) (p=0.022). High-flow nasal cannula, alone or in combination with head-of-bed elevation also improved overnight oxygenation. No harmful events were observed.

CONCLUSION

The combination of high-flow nasal cannula and upper body elevation reduced OSA severity and nocturnal hypoxemia, suggesting a role for it as an alternate postoperative airway management strategy.

Obstructive Sleep Apnea in Neonates

Neonates have distinctive anatomic and physiologic features that predispose them to obstructive sleep apnea (OSA). The overall prevalence of neonatal OSA is unknown, although an increase in prevalence has been reported in neonates with craniofacial malformations, neurological disorders, and airway malformations. If remained unrecognized and untreated, neonatal OSA can lead to impaired growth and development, cardiovascular morbidity, and can even be life threatening. Polysomnography and direct visualization of the airway are essential diagnostic modalities in neonatal OSA. Treatment of neonatal OSA is based on the severity of OSA and associated co-morbidities. This may include medical and surgical interventions individualized for the affected neonate. Based on this, it is expected that infants with OSA have more significant healthcare utilization.

Management of Obstructive Sleep Apnea in Patients With Heart Failure

Sleep apnea is traditionally classified as obstructive sleep apnea (OSA), which occurs when the upper airway collapses due to the relaxation of oropharyngeal musculature, and central sleep apnea occurs when the brainstem cannot stimulate breathing. Most sleep apnea in patients with heart failure (HF) results from coexisting OSA and central sleep apnea (CSA), or complex sleep apnea syndrome. OSA and CSA are common in HF and can be involved in its progression by exposure to the heart to intermittent hypoxia, increased preload and afterload, activating sympathetic, and decreased vascular endothelial function. A majority of treatments have been investigated in patients with CSA and HF; however, less or short-term randomized trials demonstrated whether treating OSA in patients with HF could improve morbidity and mortality. OSA could directly influence the patient's recovery. This review will focus on past and present studies on the various therapies for OSA in patients with HF and summarize CSA treatment options for reasons of reference and completeness. More specifically, the treatment covered include surgical and non-surgical treatments and reported the positive and negative consequences for these treatment options, highlighting possible implications for clinical practice and future research directions.

Sleep Apnea Syndrome (SAS) Clinical Practice Guidelines 2020

The prevalence of sleep disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern countries, including Japan. Since 1998, when health insurance coverage became available, the number of patients using continuous positive airway pressure (CPAP) therapy for sleep apnea has increased sharply, with the number of patients about to exceed 500,000 in Japan. Although the "Guidelines for Diagnosis and Treatment of Sleep Apnea Syndrome (SAS) in Adults" was published in 2005, a new guideline was prepared in order to indicate the standard medical care based on the latest trends, as supervised by and in cooperation with the Japanese Respiratory Society and the "Survey and Research on Refractory Respiratory Diseases and Pulmonary Hypertension" Group, of Ministry of Health, Labor and Welfare and other related academic societies, including the Japanese Society of Sleep Research, in addition to referring to the previous guidelines. Because sleep apnea is an interdisciplinary field covering many areas, this guideline was prepared including 36 clinical questions (CQs). In the English version, therapies and managements for SAS, which were written from CQ16 to 36, were shown. The Japanese version was published in July 2020 and permitted as well as published as one of the Medical Information Network Distribution Service (Minds) clinical practice guidelines in Japan in July 2021.

Guidelines for Perioperative Care in Bariatric Surgery: Enhanced Recovery After Surgery (ERAS) Society Recommendations: A 2021 Update

Background

This is the second updated Enhanced Recovery After Surgery (ERAS®) Society guideline, presenting a consensus for optimal perioperative care in bariatric surgery and providing recommendations for each ERAS item within the ERAS® protocol.

Methods

A principal literature search was performed utilizing the Pubmed, EMBASE, Cochrane databases and ClinicalTrials.gov through December 2020, with particular attention paid to meta-analyses, randomized controlled trials and large prospective cohort studies. Selected studies were examined, reviewed and graded according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. After critical appraisal of these studies, the group of authors reached consensus regarding recommendations.

Results

The quality of evidence for many ERAS interventions remains relatively low in a bariatric setting and evidence-based practices may need to be extrapolated from other surgeries.

Conclusion

A comprehensive, updated evidence-based consensus was reached and is presented in this review by the ERAS® Society.

Sleep Apnea Syndrome (SAS) Clinical Practice Guidelines 2020

The prevalence of sleep-disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern countries, including Japan. Since 1998, when health insurance coverage became available, the number of patients using continuous positive airway pressure (CPAP) therapy for sleep apnea has increased sharply, with the number of patients about to exceed 500,000 in Japan. Although the "Guidelines for Diagnosis and Treatment of Sleep Apnea Syndrome (SAS) in Adults" was published in 2005, a new guideline was prepared to indicate the standard medical care based on the latest trends, as supervised by and in cooperation with the Japanese Respiratory Society and the "Survey and Research on Refractory Respiratory Diseases and Pulmonary Hypertension" Group, of Ministry of Health, Labor and Welfare and other related academic societies, including the Japanese Society of Sleep Research, in addition to referring to the previous guidelines. Since sleep apnea is an interdisciplinary field covering many areas, this guideline was prepared including 36 clinical questions (CQs). In the English version, therapies and managements for SAS, which were written from CQ16 to 36, were shown. The Japanese version was published in July 2020 and permitted as well as published as one of the Medical Information Network Distribution Service (Minds) clinical practice guidelines in Japan in July 2021.

Selective Continuous Positive Airway Pressure Withdrawal With Supplemental Oxygen During Slow-Wave Sleep as a Method of Dissociating Sleep Fragmentation and Intermittent Hypoxemia-Related Sleep Disruption in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is considered to impair memory processing and increase the expression of amyloid-β (Aβ) and risk for Alzheimer’s disease (AD). Given the evidence that slow-wave sleep (SWS) is important in both memory and Aβ metabolism, a better understanding of the mechanisms by which OSA impacts memory and risk for AD can stem from evaluating the role of disruption of SWS specifically and, when such disruption occurs through OSA, from evaluating the individual contributions of sleep fragmentation (SF) and intermittent hypoxemia (IH). In this study, we used continuous positive airway pressure (CPAP) withdrawal to recapitulate SWS-specific OSA during polysomnography (PSG), creating conditions of both SF and IH in SWS only. During separate PSGs, we created the conditions of SWS fragmentation but used oxygen to attenuate IH. We studied 24 patients (average age of 55 years, 29% female) with moderate-to-severe OSA [Apnea-Hypopnea Index (AHI); AHI4% > 20/h], who were treated and adherent to CPAP. Participants spent three separate nights in the laboratory under three conditions as follows: (1) consolidated sleep with CPAP held at therapeutic pressure (CPAP); (2) CPAP withdrawn exclusively in SWS (OSA_SWS) breathing room air; and (3) CPAP withdrawn exclusively in SWS with the addition of oxygen during pressure withdrawal (OSA_SWS + O₂). Multiple measures of SF (e.g., arousal index) and IH (e.g., hypoxic burden), during SWS, were compared according to condition. Arousal index in SWS during CPAP withdrawal was significantly greater compared to CPAP but not significantly different with and without oxygen (CPAP = 1.1/h, OSA_SWS + O2 = 10.7/h, OSA_SWS = 10.6/h). However, hypoxic burden during SWS was significantly reduced with oxygen compared to without oxygen [OSA_SWS + O₂ = 23 (%min)/h, OSA_SWS = 37 (%min)/h]. No significant OSA was observed in non-rapid eye movement (REM) stage 1 (NREM 1), non-REM stage 2 (NREM 2), or REM sleep (e.g., non-SWS) in any condition. The SWS-specific CPAP withdrawal induces OSA with SF and IH. The addition of oxygen during CPAP withdrawal results in SF with significantly less severe hypoxemia during the induced respiratory events in SWS. This model of SWS-specific CPAP withdrawal disrupts SWS with a physiologically relevant stimulus and facilitates the differentiation of SF and IH in OSA.

Parametric Analysis of an Integrated Model of Cardio-respiratory Interactions in Adults in the Context of Obstructive Sleep Apnea

An original integrated model of cardio-respiratory interactions is presented in this paper with the objective of studying the acute physiological responses evoked by obstructive sleep apnea events in adults. A comprehensive sensitivity analysis of the model is proposed during the simulation of a 20 s obstructive apnea episode using the Morris' screening method and local sensitivity analysis. The more relevant parameters are related to the following mechanisms of the physiology: (i) the fraction of oxygen in inspired air, (ii) metabolic rates (oxygen consumption rate, CO₂ production rate); (iii) chemoreflex (gains and time constants) (iv) respiratory mechanics (lung compliance and unstressed volume of air in the alveoli). These results highlight significant physiological variables that may be particularly useful for the development of novel diagnostic and therapeutic strategies, integrating a virtual patient approach.

Impact of nocturnal oxygen and CPAP on the ventilatory response to hypoxia in OSA patients free of overt cardiovascular disease

A primary characteristic of obstructive sleep apnea (OSA) is chronic exposure to intermittent hypoxia (IH) due to repeated upper airway obstruction. Chronic IH exposure is believed to increase OSA severity over time by enhancing the acute ventilatory response to hypoxia (AHVR), thus promoting ventilatory overshoot when apnea ends and perpetuation of apnea during sleep. Continuous positive airway pressure (CPAP), the gold-standard treatment of OSA, reduces the AHVR, believed to result from correction of IH. However, CPAP also corrects ancillary features of OSA such as intermittent hypercapnia, negative intrathoracic pressure and surges in sympathetic activity, which may also contribute to the reduction in AHVR. Therefore, the objective of this study was to investigate the impact of nocturnal oxygen therapy (to remove IH only) and CPAP (to correct IH and ancillary features of OSA) on AHVR in newly diagnosed OSA patients. Fifty-two OSA patients and twenty-two controls were recruited. The AHVR was assessed using a 5 min iscopanic-hypoxic challenge before, and after, treatment of OSA by nocturnal oxygen therapy and CPAP. Following baseline measurements, OSA patients were randomly assigned to nocturnal oxygen therapy (Oxygen, n = 26) or no treatment (Air; n = 26). The AHVR was re-assessed following two weeks of oxygen therapy or no treatment, after which all patients were treated with CPAP. The AHVR was quantified following ~4 weeks of adherent CPAP therapy (n = 40). Both nocturnal oxygen and CPAP treatments improved hypoxemia (p < 0.05), and, as expected, nocturnal oxygen therapy did not completely abolish respiratory events (i.e., apneas/hypopneas). Averaged across all OSA patients, nocturnal oxygen therapy did not change AHVR from baseline to post-oxygen therapy. Similarly, the AHVR was not altered pre- and post-CPAP (p > 0.05). However, there was a significant decrease in AHVR with both nocturnal oxygen therapy and CPAP in patients in the highest OSA severity quartile (p < 0.05). Nocturnal oxygen therapy and CPAP both reduce the AHVR in patients with the most severe OSA. Therefore, IH appears to be the primary mechanism producing ventilatory instability in patients with severe OSA via enhancement of the AHVR.

Sleep Disordered Breathing and Cardiovascular Disease: JACC State-of-the-Art Review

Sleep disordered breathing causes repetitive episodes of nocturnal hypoxemia, sympathetic nervous activation, and cortical arousal, often associated with excessive daytime sleepiness. Sleep disordered breathing is common in people with, or at risk of, cardiovascular (CV) disease including those who are obese or have hypertension, coronary disease, heart failure, or atrial fibrillation. Current therapy of obstructive sleep apnea includes weight loss (if obese), exercise, and positive airway pressure (PAP) therapy. This improves daytime sleepiness. Obstructive sleep apnea is associated with increased CV risk, but treatment with PAP in randomized trials has not been shown to improve CV outcome. Central sleep apnea (CSA) is not usually associated with daytime sleepiness in heart failure or atrial fibrillation and is a marker of increased CV risk, but PAP has been shown to be harmful in 1 randomized trial. The benefits of better phenotyping, targeting of higher-risk patients, and a more personalized approach to therapy are being explored in ongoing trials.

Pharmacologically Induced Ventilatory Depression in the Postoperative Patient: A Sleep-Wake State-Dependent Perspective

Pharmacologically induced ventilatory depression (PIVD) is a common postoperative complication with a spectrum of severity ranging from mild hypoventilation to severe ventilatory depression, potentially leading to anoxic brain injury and death. Recent studies, using continuous monitoring technologies, have revealed alarming rates of previously undetected severe episodes of postoperative ventilatory depression, rendering the recognition of such episodes by the standard intermittent assessment practice, quite problematic. This imprecise description of the epidemiologic landscape of PIVD has thus stymied efforts to understand better its pathophysiology and quantify relevant risk factors for this postoperative complication. The residual effects of various perianesthetic agents on ventilatory control, as well as the multiple interactions of these drugs with patient-related factors and phenotypes, make postoperative recovery of ventilation after surgery and anesthesia a highly complex physiological event. The sleep-wake, state-dependent variation in the control of ventilation seems to play a central role in the mechanisms potentially enhancing the risk for PIVD. Herein, we discuss emerging evidence regarding the epidemiology, risk factors, and potential mechanisms of PIVD.

Period-to-Period Variability of Moderate/Severe Obstructive Sleep Apnoea

INTRODUCTION

The severity of obstructive sleep apnoea (OSA) is highly variable on a night-to-night basis. Patients are commonly categorised based on the severity of their OSA, and this is then used to influence management and reimbursement, including continuous positive airway pressure (CPAP). We aimed to establish to what extent the OSA severity category changes during two periods of OSA, based on mean and maximum oxygen desaturation index (ODI).

METHODS

Patients with a diagnosis of moderate to severe OSA who had been on CPAP for greater than 1 year were included in this study. Subjects underwent two periods of CPAP withdrawal for four nights each.

RESULTS

Twenty-five patients completed the study. Based on the mean ODI of the four nights, 14 (56%) patients changed OSA severity categorisation, with three (12%) changing category to mild. Based on the maximum ODI of the four nights, nine (36%) patients changed OSA severity categorisation, with one (4%) changing category to mild. One third to a half of patients' OSA severity category changed between the two periods of four night's CPAP withdrawal.

CONCLUSIONS

OSA is highly variable on a period-to-period basis as well as on a night-to-night basis. We believe the concept of patients having a definable and 'real' level of OSA severity is therefore flawed. OSA severity should be based mainly on symptoms, as these are the dominant reasons for treatment, and the sleep study should be used qualitatively to ascertain whether respiratory events are the likely cause of the symptoms.

TRIAL REGISTRATION

ISRCTN17987510.

Paediatrics: how to manage obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is defined as the intermittent reduction or cessation of airflow due to partial or complete obstruction of the upper airway during sleep. Paediatric OSAS has specific contributing factors, presenting symptoms and management strategies in various age groups. Untreated OSAS can lead to detrimental effects on neurocognitive development and cardiovascular and metabolic functions of a growing child. In the past decade, practice guidelines have been developed to guide the evaluation and management of OSAS. This article provides a narrative review on the current diagnostic and treatment options for paediatric OSAS. Alternative diagnostic tools other than the standard polysomnography are discussed. Adenotonsillectomy is considered the first-line therapy yet it is not suitable for treatment of all OSAS cases. Nocturnal non-invasive positive airway pressure ventilation is effective and could be the priority treatment for patients with complex comorbidities, residual OSAS post-adenotonsillectomy or obesity. However, intolerance and non-adherence are major challenges of positive airway pressure therapy especially in young children. There is increasing evidence for watchful waiting and other gentler alternative treatment options in mild OSAS. The role of anti-inflammatory drugs as the primary or adjunctive treatment is discussed. Other treatment options, including weight reduction, orthodontic procedures and myofunctional therapy, are indicated for selected patients. Nevertheless, the successful management of paediatric OSAS often requires a multidisciplinary team approach.

Effect of One Night of Nocturnal Oxygen Supplementation on Highland Patients With OSA: A Randomized, Crossover Trial

BACKGROUND

The treatment of OSA in highland residents is not established.

RESEARCH QUESTIONS

Does nocturnal oxygen supplementation (NOS) improve sleep-related breathing disturbances, nocturnal oxygenation, and cognitive performance in patients with OSA living at 3,200 m?

STUDY DESIGN AND METHODS

Forty patients with OSA permanently living in Shangri-La, China at 3,200 m (median age [interquartile range], 47.0 [44.0-53.0] years; oxygen desaturation index, 38.4/h [34.2/h-52.3/h]), were randomly assigned to receive nasal NOS and sham oxygen (ambient air), for one night each, at 2 L/min, in a crossover design, separated by a washout period of 2 weeks. During treatment nights polysomnography was performed, and further outcomes were evaluated the next morning. The primary outcome was the difference in apnea-hypopnea index (AHI) between nights with NOS and nights with sham oxygen.

RESULTS

During nights with sham oxygen, the median (interquartile range) total AHI was 43.4/h (31.1/h-67.5/h), the obstructive AHI was 41.9/h (28.5/h-66.8/h), and the central AHI was 0.6/h (0.1/h-1.3/h); blood oxygenation as determined by pulse oximetry (Spo₂) was 87.0% (84.5%-89.0%). In intention-to-treat analysis, NOS decreased the total AHI by a median of 17.9/h (95% CI, 8.0/h-27.1/h; P < .001), through a reduction in obstructive AHI by 16.0/h (95% CI, 6.8/h-26.0/h; P < .001) and central AHI by 0.4/h (95% CI, 0.1/h-0.9/h; P < .001). NOS also increased Spo₂ by 7.0% (95% CI, 6.0%-8.0%; P < .001). Heart rate during sleep and pulse rate in the morning after NOS were significantly reduced, but subjective sleep quality and cognitive performance showed no changes.

INTERPRETATION

In highland residents with OSA, NOS significantly improved sleep-related breathing disturbances and nocturnal oxygenation. NOS also reduced heart rate during sleep and morning pulse rate. If these beneficial effects are confirmed in longer term studies, NOS may be a treatment option for highland patients with OSA who cannot be treated by CPAP.

TRIAL REGISTRY

Chinese Clinical Trial Registry; No.: ChiCTR1800017715; URL: http://www.chictr.org.cn/showproj.aspx?proj=29768.

Oxygen Therapy in Sleep-Disordered Breathing

Sleep-disordered breathing (SDB) is highly prevalent in adults and leads to significant cardiovascular and neurologic sequelae. Intermittent hypoxia during sleep is a direct consequence of SDB. Administration of nocturnal supplemental oxygen (NSO) has been used as a therapeutic alternative to positive airway pressure (PAP) in SDB. NSO significantly improves oxygen saturation in OSA but is inferior to PAP in terms of reducing apnea severity and may prolong the duration of obstructive apneas. The effect of NSO on daytime sleepiness remains unclear, but NSO may improve physical function-related quality of life in OSA. Its effects on BP reduction remain inconclusive. The effects of NSO vs PAP in OSA with comorbid COPD (overlap syndrome) are unknown. NSO is effective in reducing central sleep apnea related to congestive heart failure; however, its impact on mortality and cardiovascular clinical outcomes are being investigated in an ongoing clinical trial. In conclusion, studies are inconclusive or limited regarding clinical outcomes with oxygen therapy compared with sham or PAP therapy in patients with OSA and overlap syndrome. Oxygen does mitigate central sleep apnea. This review examines the crucial knowledge gaps and suggests future research priorities to clarify the effects of optimal dose and duration of NSO, alone or in combination with PAP, on cardiovascular, sleep, and cognitive outcomes.

Interstitial lung disease and obstructive sleep apnea

Obstructive sleep apnea (OSA) is one of the most common comorbidities in patients with interstitial lung disease (ILD). Growing evidence highlights the significance of sleep disturbance on health outcomes in this population. The relationships between ILD and OSA are complex and possibly bidirectional, with multiple mechanisms postulated for the pathogenic and physiologic links. This review synthesizes current evidence and hypotheses regarding different aspects of the relationships between ILD and OSA, emphasizing the interactions between epidemiology, pathogenesis, and pathophysiology.

Neural crest-specific deletion of Bmp7 leads to midfacial hypoplasia, nasal airway obstruction, and disordered breathing modelling Obstructive Sleep Apnea

Pediatric obstructive sleep apnea (OSA), a relatively common sleep-related breathing disorder (SRBD) affecting approximately 1-5% of children, is often caused by anatomical obstruction and/or collapse of the nasal and/or pharyngeal airways. The resulting sleep disruption and intermittent hypoxia lead to various systemic morbidities. Predicting the development of OSA from craniofacial features alone is currently not possible and a controversy remains if upper airway obstruction facilitates reduced midfacial growth or vice-versa. Currently, there is no rodent model that recapitulates both the development of craniofacial abnormalities and upper airway obstruction to address these questions. Here, we describe that mice with a neural crest-specific deletion of Bmp7 (Bmp7ncko) present with shorter, more acute angled cranial base, midfacial hypoplasia, nasal septum deviation, turbinate swelling and branching defects, and nasal airway obstruction. Interestingly, several of these craniofacial features develop after birth during periods of rapid midfacial growth and precede the development of an upper airway obstruction. We identified that in this rodent model, no single feature appeared to predict upper airway obstruction, but the sum of those features resulted in a reduced breathing frequency, apneas and overall reduced oxygen consumption. Metabolomics analysis of serum from peripheral blood identified increased levels of hydroxyproline, a metabolite upregulated under hypoxic conditions. As this model recapitulates many features observed in OSA, it offers unique opportunities for studying how upper airway obstruction affects breathing physiology and leads to systemic morbidities.

Comparing the effects of supplemental oxygen therapy and continuous positive airway pressure on patients with obstructive sleep apnea: a meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

Obstructive sleep apnea (OSA) is associated with hypertension, psychological impairment, neurocognitive dysfunction, and poor quality of sleep. Continuous positive airway pressure (CPAP) has been confirmed to effectively improve OSA, while the effects of supplemental oxygen therapy on OSA have still remained controversial. This meta-analysis aimed to compare the effects of supplemental oxygen therapy and CPAP on patients with OSA.

METHODS

PubMed, Cochrane library, EMBASE, and Web of Science databases were systematically searched from inception until April 2020. Randomized controlled trials (RCTs) that compared the effects of supplemental oxygen therapy and CPAP on patients with OSA were selected without language restriction.

RESULTS

In this meta-analysis, 8 RCTs that involved 887 patients were found eligible for further analyses. Pooled data showed that there was no significant difference in improving nocturnal oxygen saturation (SpO₂) level (95% confidence interval (CI) = - 1.17 to 1.53) or symptoms of depression (95%CI = - 0.69 to 1.19) between supplemental oxygen therapy and CPAP. Supplemental oxygen therapy was found less effective in reducing apnea-hypopnea index (AHI), time of SpO₂ < 90%, blood pressure, and improving quality of sleep compared with CPAP. A subgroup analysis based on flow rate of oxygen indicated that the effects of supplemental oxygen therapy on blood pressure significantly differed. Furthermore, an improvement in overall time of SpO₂ < 90% was correlated to duration of supplemental oxygen therapy.

CONCLUSIONS

CPAP is clinically effective for the treatment of patients with OSA. However, supplemental oxygen therapy can be cautiously used for improving nocturnal hypoxia and symptoms of depression when CPAP is not acceptable or not tolerated. Supplemental oxygen therapy is a promising option to alleviate partial disorders of OSA. Further studies need to focus on flow rate of oxygen and duration of supplemental oxygen therapy.

Recurrent Pneumothorax with CPAP Therapy for Obstructive Sleep Apnea

Pulmonary barotrauma such as pneumothorax (PTX) is a known complication of invasive mechanical ventilation. However, it is uncommonly reported with the use of noninvasive positive pressure ventilation (NPPV) and CPAP (continuous positive airway pressure) therapy. We present a case of a 66-year-old female who presented with chronic dyspnea on exertion secondary to right-sided diaphragmatic hernia. The patient also underwent a home sleep study which suggested obstructive sleep apnea (OSA) for which she was initiated on CPAP. She then underwent surgical repair of her right diaphragmatic hernia. The patient developed pneumothorax three times over the course of the following several months, once on the right side and twice on the left side. The patient's incidences of PTX had a temporal association with the CPAP initiation. Her CPAP therapy was discontinued permanently after the third occurrence of PTX. With this case report, we highlight the risk of barotrauma with the use of CPAP for OSA. There are very few reported cases of PTX in association with NPPV therapy for OSA. The lung-protective ventilation strategies and limiting the positive airway pressures can help reduce the risk of pulmonary barotrauma with CPAP.

Supplemental Oxygen for Treatment of Infants With Obstructive Sleep Apnea

STUDY OBJECTIVES

Supplemental oxygen has been shown to decrease the frequency of obstructive respiratory events during sleep, but may result in alveolar hypoventilation. Limited information exists on the effect of supplemental oxygen on sleep and respiratory events in infants with obstructive sleep apnea (OSA).

METHODS

We conducted a retrospective study of infants with OSA who had sleep studies performed from 2007-2012. All infants underwent a room air diagnostic sleep study (RA-PSG), followed by a sleep study while breathing supplemental oxygen via nasal cannula (O₂-PSG) on a separate night. Infants with split-night studies or with inadequate sleep time were excluded.

RESULTS

Fifty-nine infants met criteria for entry into analysis. The mean age of infants at the time of RA-PSG was 13.0 ± 11.7 weeks and at O₂-PSG was 15.4 ± 13.0 weeks. The obstructive AHI decreased from 19.7 ± 13.0 during RA-PSG to 10.6 ± 11.7 during O₂-PSG (P < .001). The duration of longest obstructive apnea increased from 11.0 ± 4.2 seconds to 13.4 ± 7.4 seconds (P = .01). The lowest saturation associated with obstructive apneas increased from 80.7 ± 6.8% to 90.0 ± 6.7% (P < .001). Carbon dioxide data showed no difference in ventilation after supplemental oxygen administration. There was no significant change in the spontaneous arousal index, however, the percentage of respiratory events associated with arousal increased from 20.7 ± 11.1% to 35.7 ± 19.7% (P < .001).

CONCLUSIONS

Infants with OSA who received supplemental oxygen had a significant decrease in the frequency of obstructive respiratory events and improved oxygenation without adverse effect on alveolar ventilation. These data suggest that supplemental oxygen may be an effective treatment for infants with OSA who are not good candidates for continuous positive airway pressure or surgery.

CITATION

Brockbank J, Astudillo CL, Che D, Tanphaichitr A, Huang G, Tomko J, Simakajornboon N. Supplemental oxygen for treatment of infants with obstructive sleep apnea. J Clin Sleep Med. 2019;15(8):1115-1123.

Diagnosis and Management of Obstructive Sleep Apnea: A Review

IMPORTANCE

Obstructive sleep apnea (OSA) affects 17% of women and 34% of men in the US and has a similar prevalence in other countries. This review provides an update on the diagnosis and treatment of OSA.

OBSERVATIONS

The most common presenting symptom of OSA is excessive sleepiness, although this symptom is reported by as few as 15% to 50% of people with OSA in the general population. OSA is associated with a 2- to 3-fold increased risk of cardiovascular and metabolic disease. In many patients, OSA can be diagnosed with home sleep apnea testing, which has a sensitivity of approximately 80%. Effective treatments include weight loss and exercise, positive airway pressure, oral appliances that hold the jaw forward during sleep, and surgical modification of the pharyngeal soft tissues or facial skeleton to enlarge the upper airway. Hypoglossal nerve stimulation is effective in select patients with a body mass index less than 32. There are currently no effective pharmacological therapies. Treatment with positive airway pressure lowers blood pressure, especially in patients with resistant hypertension; however, randomized clinical trials of OSA treatment have not demonstrated significant benefit on rates of cardiovascular or cerebrovascular events.

CONCLUSIONS AND RELEVANCE

OSA is common and the prevalence is increasing with the increased prevalence of obesity. Daytime sleepiness is among the most common symptoms, but many patients with OSA are asymptomatic. Patients with OSA who are asymptomatic, or whose symptoms are minimally bothersome and pose no apparent risk to driving safety, can be treated with behavioral measures, such as weight loss and exercise. Interventions such as positive airway pressure are recommended for those with excessive sleepiness and resistant hypertension. Managing asymptomatic OSA to reduce cardiovascular and cerebrovascular events is not currently supported by high-quality evidence.

Prognostic value of sleep apnea and nocturnal hypoxemia in patients with decompensated heart failure

Background

Nocturnal hypoxemia is an important factor underlying the impact of sleep apnea on heart failure. It remains unclear whether nocturnal hypoxemia has a greater prognostic value in acute decompensated heart failure (ADHF) compared with the frequency of sleep apnea.

Hypothesis

Nocturnal hypoxemia might be better than the frequency of sleep apnea in predicting the outcomes in ADHF.

Methods

Sleep studies were prospectively performed during an ADHF hospitalization from January 2015 to December 2017. Sleep apnea was defined as the apnea‐hypopnea index (AHI) ≥15/h. The severity of nocturnal hypoxemia was determined by the percentage of time with saturation below 90% (T90%). The endpoint was the first event of all‐cause death, heart transplantation, implantation of left ventricular assist device, unplanned hospitalization for worsening heart failure, acute coronary syndrome, significant arrhythmias, or stroke.

Results

Of 382 patients, 189 (49.5%) had sleep apnea. The endpoint incidence did not differ between AHI categories (≥15/h vs <15/h: 52.4% vs 44.6%, log rank P = .353), but did between T90% categories (≥3.6% vs <3.6%: 54.5% vs 42.4%, log rank P = .023). Multivariate Cox regression analysis showed that T90% was independently associated with the endpoint (hazard ratio [HR] 1.008, 95% confidence interval [CI] 1.001‐1.016, P = .033), whereas AHI was not; the risk of the endpoint increased by 40.8% in patients with T90% ≥3.6% (HR 1.408, 95%CI 1.030‐1.925, P = .032).

Conclusion

Nocturnal hypoxemia had a greater prognostic value in ADHF than the frequency of sleep apnea.

Less pain and earlier discharge after implementation of a multidisciplinary enhanced recovery after surgery (ERAS) protocol for laparoscopic sleeve gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) may be complicated by postoperative pain, nausea, and vomiting, with consequent increases in length of stay (LOS), decreased patient satisfaction, and higher costs. While enhanced recovery after surgery (ERAS) protocols have been in circulation for many years, there is no standard ERAS protocol for bariatric surgery.

METHODS

Data were collected prospectively and compared to a historical control. All patients undergoing LSG, ages 18 to 75, were included in the pathway; those with preoperative chronic opioid use were excluded from our results. Statistical analysis was performed using t-statistics and chi-squared test. Ninety patients undergoing LSG, performed by a single surgeon, were included in our ERAS group from November 26, 2018, to April 30, 2019, and were compared to a historical control of 570 patients who underwent LSG over the previous 5 years (pre-ERAS). Measured outcomes included discharge opioid prescriptions issued, hospital length of stay, 30-day readmissions, reoperations, morbidity, and mortality.

RESULTS

Ten (11%) ERAS patients vs 100% of pre-ERAS patients received opioid prescriptions upon, or after, discharge (p < 0.001). The ERAS group LOS decreased to 1.36 days vs 2.40 days in the pre-ERAS group (p < 0.001). 30-day readmission rates were 0% for ERAS patients vs 3.09% for pre-ERAS patients (p = 0.149). 30-day reoperation rates were 0% for ERAS patients vs 0.54% for pre-ERAS patients (p = 1). Thirty-day morbidity rates were 3.33% (3) for ERAS patients vs 3.27% for pre-ERAS patients (p = 1); there was no 30-day mortality in either group.

CONCLUSION

ERAS for LSG results in a clinical and statistically significant reduction in postoperative opioid use and LOS, without increasing 30-day readmissions, reoperations, morbidity, or mortality.

Oxygen for the treatment of obstructive sleep apnoea hypopnoea syndrome

Oxygen, in the form of diatomic oxygen (O₂), comprises 20.8% of the Earth's atmosphere and is essential to most life forms on the planet. In 1777, Lavoisier was the first to name oxygen and recognise that it was a chemical element involved in combustion.

Nocturnal oxygen therapy cannot currently be recommended as a sole treatment for obstructive sleep apnoeahttp://bit.ly/2kuAsPU

Obesity and Obstructive Sleep Apnea in the Ambulatory Patient

Obesity and obstructive sleep apnea (OSA) are often associated with increased perioperative risks and challenges for the anesthesiologist. This article addresses the current controversies surrounding perioperative care of morbidly obese patients with or without OSA scheduled for ambulatory surgery, particularly in a free-standing ambulatory center. Topics discussed include preoperative selection of obese and OSA patients for ambulatory surgeries, intraoperative methods to reduce perioperative risk, and appropriate postoperative care.

Effect of Supplemental Oxygen on Blood Pressure in Obstructive Sleep Apnea (SOX). A Randomized Continuous Positive Airway Pressure Withdrawal Trial

RATIONALE

Obstructive sleep apnea (OSA) is associated with systemic hypertension. Either overnight intermittent hypoxia, or the recurrent arousals that occur in OSA, could cause the daytime increases in blood pressure (BP).

OBJECTIVES

To establish the role of intermittent hypoxia in the increased morning BP in patients with OSA.

METHODS

Randomized, double-blinded, crossover trial assessing the effects of overnight supplemental oxygen versus air (sham) on morning BP, after continuous positive airway pressure (CPAP) withdrawal in patients with moderate to severe OSA. The primary outcome was the change in home morning BP after CPAP withdrawal for 14 nights, oxygen versus air. Secondary outcomes included oxygen desaturation index (ODI), apnea-hypopnea index (AHI), subjective sleepiness (Epworth Sleepiness Scale score), and objective sleepiness (Oxford Sleep Resistance Test).

MEASUREMENTS AND MAIN RESULTS

Supplemental oxygen virtually abolished the BP rise after CPAP withdrawal and, compared with air, significantly reduced the rise in mean systolic BP (-6.6 mm Hg; 95% confidence interval [CI], -11.3 to -1.9; P = 0.008), mean diastolic BP (-4.6 mm Hg; 95% CI, -7.8 to -1.5; P = 0.006), and median ODI (-23.8/h; interquartile range, -31.0 to -16.3; P < 0.001) after CPAP withdrawal. There was no significant difference, oxygen versus air, in AHI, subjective sleepiness, or objective sleepiness.

CONCLUSIONS

Supplemental oxygen virtually abolished the rise in morning BP during CPAP withdrawal. Supplemental oxygen substantially reduced intermittent hypoxia, but had a minimal effect on markers of arousal (including AHI), subjective sleepiness, or objective sleepiness. Therefore intermittent hypoxia, and not recurrent arousals, appears to be the dominant cause of daytime increases in BP in OSA.

Sleep physiology and disorders in aging and dementia

Sleep problems occur commonly in normal and pathologic aging. Older adults typically have more difficulty falling asleep and remaining asleep, report more daytime napping, and have an increased prevalence of primary sleep disorders such as insomnia, parasomnias, sleep apnea, and sleep-related movement disorders. Medical and psychiatric disorders as well as medications used to treat them also contribute to sleep disturbances in aging. Patients with mild cognitive impairment and dementia have more severe sleep problems, and disturbed sleep and sleep disorders contribute to earlier onset and more rapid progression of neurodegenerative disorders. Approaches to diagnosing and treating sleep disorders in the elderly are discussed.

From CPAP to tailored therapy for obstructive sleep Apnoea

Obstructive Sleep Apnoea (OSA) is a common sleep disorder that is associated with daytime symptoms and a range of comorbidity and mortality. Continuous Positive Airway Pressure (CPAP) therapy is highly efficacious at preventing OSA when in use and has long been the standard treatment for newly diagnosed patients. However, CPAP therapy has well recognised limitations in real world effectiveness due to issues with patient acceptance and suboptimal usage. There is a clear need to enhance OSA treatment strategies and options. Although there are a range of alternative treatments (e.g. weight loss, oral appliances, positional devices, surgery, and emerging therapies such as sedatives and oxygen), generally there are individual differences in efficacy and often OSA will not be completely eliminated. There is increasing recognition that OSA is a heterogeneous disorder in terms of risk factors, clinical presentation, pathophysiology and comorbidity. Better characterisation of OSA heterogeneity will enable tailored approaches to therapy to ensure treatment effectiveness. Tools to elucidate individual anatomical and pathophysiological phenotypes in clinical practice are receiving attention. Additionally, recognising patient preferences, treatment enhancement strategies and broader assessment of treatment effectiveness are part of tailoring therapy at the individual level. This review provides a narrative of current treatment approaches and limitations and the future potential for individual tailoring to enhance treatment effectiveness.

Effects of obstructive sleep apnea and its treatment over the erectile function: a systematic review

Erectile dysfunction (ED) is considered a condition with a broad range of etiologies. Obstructive sleep apnea (OSA) syndrome is one of the lesser studied risk factors for ED. We intend to summarize the current evidence on the relationship between OSA and sexual impairment, focusing on the results in terms of erectile function of the different therapies offered to OSA patients. A systematic review was conducted, selecting articles related to the physiology of OSA and ED, and to the treatments of OSA syndrome and their reported outcomes in erectile and sexual function. Higher prevalences of ED in the OSA groups have been published. However, whether this effect on the erectile function occurs in the entire range of OSA severities remains unclear. Several hypotheses were proposed to explain the physiology of this association. Continuous Positive Airway Pressure as a treatment for OSA patients with ED has achieved a significative improvement in the sexual parameters in most of the studies. Phosphodiesterase type 5 inhibitors (iPDE5) on demand are useful as a treatment for ED in this subgroup of patients, with high satisfaction rates. The surgical treatment for the OSA evidenced benefits over the erectile function, and the effect on the sexual satisfaction of the therapy using Mandibular Advancement Devices is still undefined.

Short-term efficacy of minimally invasive treatments for adult obstructive sleep apnea: A systematic review and network meta-analysis of randomized controlled trials

Many treatments have been proposed for adult obstructive sleep apnea (OSA), but no comprehensive comparison of all interventions has been performed. We aimed to compare and rank the effectiveness of all minimally invasive treatments for adult OSA in a systematic review and network meta-analysis. Literature was searched within Ovid MedLine, EMBASE Classic+Embase, Cochrane library, and Cochrane Database of Systematic Reviews from inception to Aug 9th, 2016 for randomized controlled trials comparing minimally invasive treatments for adult OSA. The outcomes were the changes in apnea-hypopnea index (AHI) and Epworth sleepiness scale (ESS). Frequentist approach to network meta-analysis was used and treatment hierarchy was summarized according to the surfaces under the cumulative ranking curves. Eighty-nine randomized controlled trials comprising 6346 adult OSA participants and comparing 18 different interventions were included. In comparison with no treatment, positive airway pressure (PAP) was most effective in reducing AHI (23.28 [weighted mean difference]; 95% confidence interval: 19.20-27.35). PAP was ranked first followed by mandibular advancement device (MAD) in reducing AHI. Exercise was ranked first followed by cervico-mandibular support collar in reducing ESS. Considering the effectiveness in reducing both AHI and ESS, PAP was ranked the best, followed by MAD and positional therapy, while lifestyle modification alone was the least effective intervention. Interventions that are highly effective in reducing objective laboratory-derived AHI do not demonstrate equivalent effectiveness in improving patients' subjective sleepiness. Future improvement of the interventions is necessary to simultaneously improve both objective and subjective outcomes.

Post-Stroke Sleep-Disordered Breathing-Pathophysiology and Therapy Options

Sleep-disordered breathing (SDB), encompassing both obstructive and central sleep apnea, is prevalent in at least 50% of stroke patients. Small studies have shown vast improvements in post-stroke functional recovery outcomes after the treatment of SDB by continuous positive airway pressure. However, compliance to this therapy is very poor in this complex patient group. There are alternative therapy options for SDB that may be more amenable for use in at least some post-stroke patients, including mandibular advancement, supine avoidance, and oxygen therapy. There are few studies, however, that demonstrate efficacy and compliance with these alternative therapies currently. Furthermore, novel SDB-phenotyping approaches may help to provide important clinical information to direct therapy selection in individual patients. Prior to realizing individualized therapy, we need a better understanding of the pathophysiology of SDB in post-stroke patients, including the role of inherent phenotypic traits, as well as the contribution of stroke size and location. This review summarizes the available literature on SDB pathophysiology and treatment in post-stroke patients, identifies gaps in the literature, and sets out areas for further research.

Sleep-Disordered Breathing in People with Multiple Sclerosis: Prevalence, Pathophysiological Mechanisms, and Disease Consequences

Sleep problems are common in people with multiple sclerosis (MS). Reported prevalence rates of sleep-disordered breathing (SDB) vary between 0 and 87%. Differences in recruitment procedures and study designs likely contribute to the wide variance in reported prevalence rates of SBD in MS. This can make attempts to compare SDB rates in people with MS to the general population challenging. Little is known about the pathophysiological mechanisms that contribute to SDB in people with MS or whether MS contributes to SDB disease progression. However, compared to the general obstructive sleep apnea (OSA) population, there are clear differences in the clinical phenotypes of SDB in the MS population. For instance they are typically not obese and rates of SDB are often comparable or higher to the general population, despite the high female predominance of MS. Thus, the risk factors and pathophysiological causes of SDB in people with MS are likely to be different compared to people with OSA who do not have MS. There may be important bidirectional relationships between SDB and MS. Demyelinating lesions of MS in the brain stem and spinal cord could influence breathing control and upper airway muscle activity to cause SDB. Intermittent hypoxia caused by apneas during the night can increase oxidative stress and may worsen neurodegeneration in people with MS. In addition, inflammation and changes in cytokine levels may play a key role in the relationship between SDB and MS and their shared consequences. Indeed, fatigue, neurocognitive dysfunction, and depression may worsen considerably if both disorders coexist. Recent studies indicate that treatment of SDB in people with MS with conventional first-line therapy, continuous positive airway pressure therapy, can reduce fatigue and cognitive impairment. However, if the causes of SDB differ in people with MS, so too may the optimal therapy. Thus, many questions remain concerning the relationship between these two disorders and the underlying mechanisms and shared consequences. Improved understanding of these factors has the potential to unlock new therapeutic targets.

Predicting response to oxygen therapy in obstructive sleep apnoea patients using a 10-minute daytime test

There is no satisfactory treatment for obstructive sleep apnoea (OSA). Supplemental low-flow oxygen therapy (LFO2) has been shown to reduce hypoxaemia and is well tolerated by patients with OSA. However, oxygen therapy may be beneficial only to certain subsets of patients with OSA. In this study, we evaluated a 10-min awake ventilatory chemoreflex test in predicting individual OSA response to 2 months of LFO2therapy.

At baseline, patients with OSA underwent ventilatory chemoreflex testing in the afternoon, prior to the overnight polysomnography. Subjects were reassessed with polysomnography after 2 months of nocturnal oxygen treatment.

20 patients with OSA completed the study. After 2 months of O2treatment, changes in the apnoea–hypopnoea index (AHI) were significantly correlated with baseline CO2ventilatory response threshold (VRT) and chemosensitivity (p<0.05). In predicting a fall in AHI, the area under the receiver operating characteristic curve (AUC) was 0.79 for VRT and 0.89 for chemosensitivity. When these two variables were combined in a logistic regression model, the prediction effect became stronger with an AUC of 0.97, sensitivity of 0.92 and specificity of 0.83.

Our awake ventilatory chemoreflex test could be considered a simple potential clinical tool to predict individual OSA response to oxygen therapy. It could provide a novel personalised medicine approach to OSA treatment.

Home oxygen therapy: re-thinking the role of devices

INTRODUCTION

A range of devices are available for delivering and monitoring home oxygen therapy (HOT). Guidelines do not give indications for the choice of the delivery device but recommend the use of an ambulatory system in subjects on HOT whilst walking. Areas covered: We provide a clinical overview of HOT and review traditional and newer delivery and monitoring devices for HOT. Despite relevant technology advancements, clinicians, faced with many challenges when they prescribe oxygen therapy, often remain familiar to traditional devices and continuous flow delivery of oxygen. Some self-filling delivery-less devices could increase the users' level of independence with ecological advantage and, perhaps, reduced cost. Some newer portable oxygen concentrators are being available, but more work is needed to understand their performances in different diseases and clinical settings. Pulse oximetry has gained large diffusion worldwide and some models permit long-term monitoring. Some closed-loop portable monitoring devices are also able to adjust oxygen flow automatically in accordance with the different needs of everyday life. This might help to improve adherence and the practice of proper oxygen titration that has often been omitted because difficult to perform and time-consuming. Expert commentary: The prescribing physicians should know the characteristics of newer devices and use technological advancements to improve the practice of HOT.