Evaluation and Management of Obesity Hypoventilation Syndrome. An Official American Thoracic Society Clinical Practice Guideline

Intermittent Versus Sustained Hypoxemia from Sleep-disordered Breathing: Outcomes in Patients with Chronic Lung Disease and High Altitude

In a variety of physiologic and pathologic states, people may experience both chronic sustained hypoxemia and intermittent hypoxemia ("combined" or "overlap" hypoxemia). In general, hypoxemia in such instances predicts a variety of maladaptive outcomes, including excess cardiovascular disease or mortality. However, hypoxemia may be one of the myriad phenotypic effects in such states, making it difficult to ascertain whether adverse outcomes are primarily driven by hypoxemia, and if so, whether these effects are due to intermittent versus sustained hypoxemia.

The Role of Obstructive Sleep Apnea in Hypercapnic Respiratory Failure Identified in Critical Care, Inpatient, and Outpatient Settings

An emerging body of literature describes the prevalence and consequences of hypercapnic respiratory failure. While device qualifications, documentation practices, and previously performed clinical studies often encourage conceptualizing patients as having a single "cause" of hypercapnia, many patients encountered in practice have several contributing conditions. Physiologic and epidemiologic data suggest that sleep-disordered breathing-particularly obstructive sleep apnea (OSA)-often contributes to the development of hypercapnia. In this review, the authors summarize the frequency of contributing conditions to hypercapnic respiratory failure among patients identified in critical care, emergency, and inpatient settings with an aim toward understanding the contribution of OSA to the development of hypercapnia.

Obstructive Sleep Apnea, Obesity Hypoventilation Syndrome, and Pulmonary Hypertension: A State-of-the-Art Review

The pathophysiological interplay between sleep-disordered breathing (SDB) and pulmonary hypertension (PH) is complex and can involve a variety of mechanisms by which SDB can worsen PH. These mechanistic pathways include wide swings in intrathoracic pressure while breathing against an occluded upper airway, intermittent and/or sustained hypoxemia, acute and/or chronic hypercapnia, and obesity. In this review, we discuss how the downstream consequences of SDB can adversely impact PH, the challenges in accurately diagnosing and classifying PH in the severely obese, and review the limited literature assessing the effect of treating obesity, obstructive sleep apnea, and obesity hypoventilation syndrome on PH.

Obstructive Sleep Apnea and Sarcoidosis Interactions

Obstructive sleep apnea (OSA) is very prevalent in sarcoidosis patients. Sarcoidosis of the upper respiratory tract may affect upper airway patency and increase the risk of OSA. Weight gain due to steroid use, upper airway myopathy due to steroids and sarcoidosis itself, and interstitial lung disease with decreased upper airway patency are other reasons for the higher OSA prevalence seen in sarcoidosis. Several clinical manifestations such as fatigue, hypersomnolence, cognitive deficits, and pulmonary hypertension are common to both OSA and sarcoidosis. Therefore, early screening and treatment for OSA can improve symptoms and overall patient quality of life.

Analysis and applications of respiratory surface EMG: report of a round table meeting

Surface electromyography (sEMG) can be used to measure the electrical activity of the respiratory muscles. The possible applications of sEMG span from patients suffering from acute respiratory failure to patients receiving chronic home mechanical ventilation, to evaluate muscle function, titrate ventilatory support and guide treatment. However, sEMG is mainly used as a monitoring tool for research and its use in clinical practice is still limited-in part due to a lack of standardization and transparent reporting. During this round table meeting, recommendations on data acquisition, processing, interpretation, and potential clinical applications of respiratory sEMG were discussed. This paper informs the clinical researcher interested in respiratory muscle monitoring about the current state of the art on sEMG, knowledge gaps and potential future applications for patients with respiratory failure.

Sleep-disordered Breathing and Inpatient Outcomes in Nonsurgical Patients: Analysis of the Nationwide Inpatient Cohort

Rationale: Sleep-disordered breathing (SDB) is associated with increased complications and length of stay (LOS) after surgery. SDB-related adverse consequences for nonsurgical admissions are not well defined. Objectives: Evaluate associations between SDB and subtypes and LOS, cost, and mortality in nonsurgical patients. Methods: This retrospective cohort analysis used adult nonsurgical admissions from the 2017 National Inpatient Sample of the Healthcare Costs and Utilization Project. SDB associations with LOS (primary outcome), costs, and mortality were evaluated via logistic regression. Covariates included age, sex, Elixhauser Comorbidity Index, socioeconomic status, hospital type, and insurance type. Results: The cohort included 6,046,544 hospitalizations. Compared with those without SDB, patients with SDB were older (63.6 ± 13.5 vs. 57.4 ± 20.7 yr), higher proportion male (55.8% vs. 40.9%), and more likely to be White (75.7% vs. 66.5%). SDB was associated with increased odds of increased LOS and hospitalization costs (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.16-1.17 and OR, 1.67; 95% CI, 1.66-1.67 in adjusted analyses, respectively) but lower mortality (OR, 0.79; 95% CI, 0.77-0.81). The results for obstructive sleep apnea (OSA) echoed those for SDB. Obesity hypoventilation syndrome had substantially increased LOS (OR, 3.05; 95% CI, 2.98-3.13), mortality (1.76; 95% CI, 1.66-1.86), and costs (OR, 2.67; 95% CI, 2.60-2.73) even after adjustment. Conclusions: Obesity hypoventilation syndrome is associated with higher LOS, mortality, and costs during hospitalization, whereas OSA, despite higher LOS and costs, is associated with decreased mortality. Investigation is warranted on whether paradoxically higher costs but lower mortality in OSA may be indicative of less vigilance in hospitalized patients with undiagnosed SDB.

High-flow nasal cannula may prolong the length of hospital stay in patients with hypercapnic acute COPD exacerbation

BACKGROUND

High-flow nasal cannula (HFNC) is increasingly used in patients with acute exacerbation of COPD (AECOPD). We aimed to confirm whether the baseline bicarbonate is an independent predictor of outcomes in patients with hypercapnic AECOPD receiving HFNC.

METHODS

This was a secondary analysis of a multicentre randomised trial that enrolled 330 patients with non-acidotic hypercapnic AECOPD supported by HFNC or conventional oxygen treatment (COT). We compared the length of stay (LOS) in hospital and the rate of non-invasive positive pressure ventilation (NPPV) use according to baseline bicarbonate levels using the log-rank test or Cox proportional hazard model.

RESULTS

In the high bicarbonate subgroup (n = 165, bicarbonate 35.0[33.3-37.9] mmol/L, partial pressure of arterial carbon dioxide [PaCO2] 56.8[52.0-62.8] mmHg), patients supported by HFNC had a remarkably prolonged LOS in hospital when compared to COT (HR 1.59[1.16-2.17], p = 0.004), whereas patients in the low bicarbonate subgroup (n = 165, bicarbonate 28.8[27.0-30.4] mmol/L, PaCO2 48.0[46.0-50.0] mmHg) had a comparable LOS in hospital regardless of respiratory support modalities. The rate of NPPV use in patients with high baseline bicarbonate level was significantly higher than that in patients with low baseline bicarbonate level (19.4 % vs. 3.0 %, p < 0.0001). Patients with high bicarbonate level in HFNC group had a lower rate of NPPV use compared to COT group (15.4 % vs. 23.0 %, p = 0.217).

CONCLUSIONS

Among patients with non-acidotic hypercapnic AECOPD with high baseline bicarbonate level, HFNC is significantly associated with a prolonged LOS in hospital, which may be due to the reduced escalation of NPPV treatment.

TRIAL REGISTRATION

clinicaltrials.gov (NCT03003559).

Using intra-breath oscillometry in obesity hypoventilation syndrome to detect tidal expiratory flow limitation: a potential marker to optimize CPAP therapy

BACKGROUND

Continuous positive airway pressure (CPAP) therapy has profound effects in obesity hypoventilation syndrome (OHS). Current therapy initiation focuses on upper airway patency rather than the assessment of altered respiratory mechanics due to increased extrapulmonary mechanical load.

METHODS

We aimed to examine the viability of intra-breath oscillometry in optimizing CPAP therapy for OHS. We performed intra-breath oscillometry at 10 Hz in the sitting and supine positions, followed by measurements at increasing CPAP levels (none-5-10-15-20 cmH2O) in awake OHS patients. We plotted intra-breath resistance and reactance (Xrs) values against flow (V') and volume (V) to identify tidal expiratory flow limitation (tEFL).

RESULTS

Thirty-five patients (65.7% male) completed the study. We found a characteristic looping of the Xrs vs V' plot in all patients in the supine position revealing tEFL: Xrs fell with decreasing flow at end-expiration. Intra-breath variables representing expiratory decrease of Xrs became more negative in the supine position [end-expiratory Xrs (mean ± SD): -1.9 ± 1.8 cmH2O·s·L- 1 sitting vs. -4.2 ± 2.2 cmH2O·s·L- 1 supine; difference between end-expiratory and end-inspiratory Xrs: -1.3 ± 1.7 cmH2O·s·L- 1 sitting vs. -3.6 ± 2.0 cmH2O·s·L- 1 supine, p < 0.001]. Increasing CPAP altered expiratory Xrs values and loop areas, suggesting diminished tEFL (p < 0.001). 'Optimal CPAP' value (able to cease tEFL) was 14.8 ± 4.1 cmH2O in our cohort, close to the long-term support average of 13.01(± 2.97) cmH2O but not correlated. We found no correlation between forced spirometry values, patient characteristics, apnea-hypopnea index and intra-breath oscillometry variables.

CONCLUSIONS

tEFL, worsened by the supine position, can be diminished by stepwise CPAP application in most patients. Intra-breath oscillometry is a viable method to detect tEFL during CPAP initiation in OHS patients and tEFL is a possible target for optimizing therapy in OHS patients.

Impact of treating obesity hypoventilation syndrome on body mass index

STUDY OBJECTIVES

To evaluate the impact of positive airway pressure (PAP) therapy on body mass index (BMI) in patients with obesity hypoventilation syndrome (OHS) associated with obstructive sleep apnea (OSA).

METHODS

A systematic review using the following terms: "obesity hypoventilation syndrome" AND "treatment" AND "randomized" using Cochrane Central Register of Controlled Trials, Medline and Web of Science was performed from the first data available until February 10, 2023. The inclusion criteria were: (1) original article; (2) adult OHS with concomitant OSA (apnea-hypopnea index or AHI ≥5 events/h); (3) randomized trial with PAP arm and standard care (control); (4) BMI evaluation at baseline and after the first months. We performed an individual participant data meta-analysis of randomized controlled trials.

RESULTS

Our initial search retrieved 32 articles and 3 randomized studies fulfilled study criteria and were included in the final analysis, leading to a total of 342 participants. Patients were predominantly females (62%) and had OHS associated with at least mild OSA. As compared to baseline, a decrease in BMI was observed at study endpoint but this difference was not different intergroups (-0.50 ± 1.49 and -0.50 ±1.83, in control and PAP groups respectively (p=0.939)). Weight change was not associate with PAP adherence, OSA severity or use of supplemental oxygen.

CONCLUSIONS

In contrast to treatment of eucapnic OSA with PAP that is associated with weight gain, treatment of OSA+OHS patients with or without PAP is associated with weight loss. Future studies are necessary to elucidate the mechanism by which weight loss occurs.

Home NIV treatment quality in patients with chronic respiratory failure having participated to the French nationwide telemonitoring experimental program (The TELVENT study)

BACKGROUND

The ETAPES program is a national telemedicine experiment conducted in France between 2018 and 2023 to investigate whether home non-invasive ventilation (NIV) telemonitoring improves healthcare pathways in patients with chronic respiratory failure (CRF) and impacts healthcare organization. The program provides a combination of therapeutic education and NIV telemonitoring with data processed by an algorithm generating alerts. The TELVENT study objective was to analyze the evolution of ventilation quality in patients included in the ETAPES program.

METHODS

Multicentric cohort study on patients undergoing long-term NIV included in the ETAPES program between September 2018 and December 2020 and who did not refuse the use of their data for this research. Data were obtained from homecare provider databases. The primary endpoint was to attain successful NIV treatment, which was determined by a combination of daily NIV usage for > 4 h per day, low leaks, and a low apnea-hypopnea index (AHI) identified by the NIV device. Respiratory disability was assessed using the DIRECT questionnaire.

RESULTS

329 patients were included in the study of which 145 had COPD and 83 had started NIV and ETAPES within one-month delay. Approximately 25% of patients did not achieve the criteria for successful NIV at ETAPES entry. The proportion of patients with successful NIV treatment increased to 86.8% at six months (p = 0.003, Cochran-Armitage trend test) regardless of NIV history and continued to increase at 12 months in newly equipped NIV patients (93.8%, at month 12, p = 0.0026 for trend test). Over time, a significant increase in NIV use and compliance was observed, while AHI significantly decreased in the overall population. No significant decrease was observed for non-intentional leaks. Approximately 4.9 alerts were generated per patient per 6 months. Their number and type (low NIV use, high AHI or leaks) differed among patients based on their NIV history. Respiratory disability score decreased over time compared with baseline.

CONCLUSION

The TELVENT study highlights the importance of remote NIV monitoring to rapidly identify patients with unsuccessful ventilation. The combination of remote monitoring and therapeutic education may improve the quality of home NIV, especially in the first months of treatment.

Contribution of Transcutaneous PCO2 in Obesity Hypoventilation Syndrome

BACKGROUND

More and more patients have obesity-hypoventilation syndrome (OHS) because of the increasing prevalence of obesity. The accuracy of transcutaneous PCO2 (PtcCO2 ) has recently been validated. However, no study evaluated the interest of measuring systematically nocturnal PtcCO2 in the follow-up of patients with OHS and home mechanical ventilation to detect residual nocturnal hypoventilation. We aimed to evaluate the contribution of nocturnal PtcCO2 to assess nocturnal hypoventilation compared with current routine examinations, that is, daytime arterial blood gases and nocturnal pulse oximetry.

METHODS

A prospective monocentric pilot study was conducted from August 2018 to November 2019. Patients with stable OHS and who were treated with home noninvasive ventilation for at least 6 months were eligible to participate. After oral consent, we performed both diurnal arterial blood gases and combined home oximetry and capnography. The primary end point was the presence of residual nocturnal hypoventilation, defined as PaCO2 > 45 mm Hg or bicarbonate ≥ 27 mmol/L, SpO2 < 90% for ≥ 10% of the night, or PtcCO2 > 49 mm Hg for ≥ 10% of the night.

RESULTS

A total of 32 subjects were included. Twenty-nine subjects with nocturnal PtcCO2 were analyzed. Eighteen of the 29 subjects showed residual nocturnal hypoventilation. The association of diurnal arterial blood gases and nocturnal pulse oximetry revealed nocturnal hypoventilation in only 9 subjects. Among the 19 subjects with both normal blood gases and normal nocturnal pulse oximetry, 11 had nocturnal hypoventilation with transcutaneous capnography. Only one subject presented with hypoventilation symptoms (asthenia).

CONCLUSIONS

The assessment of PtcCO2 in comparison with nocturnal pulse oximetry and arterial blood gases provides important information for the diagnosis of residual nocturnal hypoventilation in the subjects with OHS who were ventilated at home.

Impact of Previous Continuous Positive Airway Pressure Use on Noninvasive Ventilation Adherence and Quality in Obesity Hypoventilation Syndrome: A Pragmatic Single-Center Cross-Sectional Study in Martinique

There is a strong relationship between obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS). When OHS is combined with severe OSA, treatment consists of continuous positive airway pressure (CPAP), followed by noninvasive ventilation (NIV) in the case of CPAP failure. Currently, the impact of a previous use of CPAP on the quality of NIV is unknown. We conducted a cross-sectional study with OHS patients, to assess the quality of NIV according to previous CPAP use. We included 75 patients with OHS on NIV (65 women, 87%). Among these, 40 patients (53.3%) who had had prior CPAP (CPAP+ group) were compared to the remaining 35 patients (46.7%) (CPAP- group). Key characteristics were comparable between the CPAP+ and the CPAP- groups: age at diagnosis of OHS was 67 ± 3 vs. 66 ± 4 years (p = 0.8), age at inclusion was 73 ± 15 vs. 69 ± 15 years (p = 0.29), number of comorbidities was 3.7 ± 1.2 vs. 3.3 ± 1.5, the Charlson index was 5.1 ± 2 vs. 4.6 ± 1.8, and BMI was 41.6 ± 7.6 kg/m2 vs. 41.2 ± 8.2, respectively, all p > 0.05. Follow-up length was greater in CPAP+ vs. CPAP- patients (5.6 ± 4.2 vs. 2.9 ± 2.9 years, p = 0.001). The quality of NIV based on daily adherence, pressure support, apnea-hypopnea index (AHI) and leaks was similar in both groups. Reduced adherence (less than 4 h daily) was found in 10 CPAP+ patients (25%) versus 7 CPAP- patients (20%), p = 0.80. NIV efficacy was also similar. This study found no difference in the quality of NIV or in adherence between patients who had had prior CPAP and those who had not. Previous CPAP does not appear to improve the quality of NIV.

Nocturnal Hypoventilation in the Patients Submitted to Thoracic Surgery

Introduction

Nocturnal hypoventilation may occur due to obesity, concomitant chronic obstructive pulmonary disease (COPD), obstructive sleep apnea, and/or the use of narcotic analgesics. The aim of the study was to evaluate the risk and severity of nocturnal hypoventilation as assessed by transcutaneous continuous capnography in the patients submitted to thoracic surgery.

Materials and Methods

The material of the study consisted of 45 obese (BMI 34.8 ± 3.7 kg/m2) and 23 nonobese (25.5 ± 3.6 kg/m2) patients, who underwent thoracic surgery because of malignant (57 patients) and nonmalignant tumors. All the patients received routine analgesic treatment after surgery including intravenous morphine sulfate. Overnight transcutaneous measurements of CO2 partial pressure (tcpCO2) were performed before and after surgery in search of nocturnal hypoventilation, i.e., the periods lasting at least 10 minutes with tcpCO2 above 55 mmHg.

Results

Nocturnal hypoventilation during the first night after thoracic surgery was detected in 10 patients (15%), all obese, three of them with COPD, four with high suspicion of moderate-to-severe OSA syndrome, and one with chronic daytime hypercapnia. In the patients with nocturnal hypoventilation, the mean tcpCO2 was 53.4 ± 6.1 mmHg, maximal tcpCO2 was 59.9 ± 8.4 mmHg, and minimal tcpCO2 was 46.4 ± 6.7 mmHg during the first night after surgery. In these patients, there were higher values of minimal, mean, and maximal tcpCO2 in the preoperative period. Nocturnal hypoventilation in the postoperative period did not influence the duration of hospitalization. Among 12 patients with primary lung cancer who died during the first two years of observation, there were 11 patients without nocturnal hypoventilation in the early postoperative period.

Conclusion

Nocturnal hypoventilation may occur in the patients after thoracic surgery, especially in obese patients with bronchial obstruction, obstructive sleep apnea, or chronic daytime hypercapnia, and does not influence the duration of hospitalization.

Clinical Evaluation of the Sleepy and Sleepless Patient

OBJECTIVE

This article addresses the approach to the evaluation of patients who present to a neurologist with excessive daytime sleepiness or difficulty sleeping.

LATEST DEVELOPMENTS

Greater emphasis on the importance of sleep reflects the growing scientific understanding that sleep is critical to overall health and well-being. Consumer sleep technologies, which measure parameters related to sleep, may provide insight into an individual's sleep-related symptoms and tendencies and have a role in patient-centered sleep evaluation when used within an appropriate clinical context.

ESSENTIAL POINTS

A thorough review of a patient's history and physical examination findings are important components of the assessment and management of their sleep-related symptoms. An understanding of how the clinical context relates to the categorization of sleep disorders can impact a patient's symptoms, comorbid neurologic disorders, and overall well-being. Many neurologic conditions are strongly associated with sleep disturbance, risk factors for the development of a sleep disorder, or both. Therefore, it is critical for neurologists to be familiar and comfortable with taking a focused sleep history. Modalities such as in-laboratory polysomnography, home sleep apnea testing, multiple sleep latency testing, and actigraphy, as well as contextualized and prudent use of data obtained from consumer sleep technologies, can be helpful in appropriately selected patients. Mindful integration of these objective data facilitates the diagnosis and management of sleep disorders.

Ketogenic diet acutely improves gas exchange and sleep apnoea in obesity hypoventilation syndrome: A non-randomized crossover study

BACKGROUND AND OBJECTIVE

Obesity hypoventilation syndrome (OHS) causes hypercapnia which is often refractory to current therapies. We examine whether hypercapnia in OHS can be improved by a ketogenic dietary intervention.

METHODS

We conducted a single-arm crossover clinical trial to examine the impact of a ketogenic diet on CO2 levels in patients with OHS. Patients were instructed to adhere to 1 week of regular diet, 2 weeks of ketogenic diet, followed by 1 week of regular diet in an ambulatory setting. Adherence was assessed with capillary ketone levels and continuous glucose monitors. At weekly visits, we measured blood gases, calorimetry, body composition, metabolic profiles, and sleep studies. Outcomes were assessed with linear mixed models.

RESULTS

A total of 20 subjects completed the study. Blood ketones increased from 0.14 ± 0.08 during regular diet to 1.99 ± 1.11 mmol/L (p < 0.001) after 2 weeks of ketogenic diet. Ketogenic diet decreased venous CO2 by 3.0 mm Hg (p = 0.008), bicarbonate by 1.8 mmol/L (p = 0.001), and weight by 3.4 kg (p < 0.001). Sleep apnoea severity and nocturnal oxygen levels significantly improved. Ketogenic diet lowered respiratory quotient, fat mass, body water, glucose, insulin, triglycerides, leptin, and insulin-like growth factor 1. Rebound hypercapnia was observed after resuming regular diet. CO2 lowering was dependent on baseline hypercapnia, and associated with circulating ketone levels and respiratory quotient. The ketogenic diet was well tolerated.

CONCLUSION

This study demonstrates for the first time that a ketogenic diet may be useful for control of hypercapnia and sleep apnoea in patients with obesity hypoventilation syndrome.

Screening and treatment of pre-bariatric surgical patients with obesity related sleep disordered breathing

BACKGROUND

There is a significant burden of sleep disordered breathing (SDB) in patients living with severe and complex obesity undergoing pre-bariatric surgery assessment. This longitudinal observational study evaluated the burden of obesity hypoventilation syndrome (OHS) in this cohort of patients and the therapeutic compliance of patients commenced on positive airway pressure treatment.

METHODS

All pre-bariatric surgery patients referred to the sleep clinic for review after an abnormal screening study between 2018 and 2022 were included. We collected data on their sleep study results, anthropometrics, co-morbid medical conditions, clinical observations, spirometry and arterial blood gas (ABG). Patients commenced on therapy were followed-up longitudinally and compliance data collected via remote monitoring.

RESULTS

A total of 116 patients were included [age: mean ± standard deviation (SD) 48.8±10.8 years; body mass index (BMI) 49.2±8.5 kg/m2; Epworth Sleepiness Scale (ESS) 8.7±5.1 points]. Fifteen patients (12.9% of cohort) were diagnosed with hypercapnic respiratory failure (pH 7.40±0.02; pO2 11.00±1.04 kPa; pCO2 6.15±0.08 kPa). Compared to eucapnic obstructive sleep apnoea (OSA) patients, they were older (51.1 vs. 48.5 years; P=0.311), had a higher BMI (51.5 vs. 48.9 kg/m2; P=0.266), more likely to be female (66.7% vs. 53.5%; P=0.275) and had a higher ESS score (10.4 vs. 8.5 points; P=0.177). On binomial regression analysis insulin dependent diabetes was the only patient characteristic of significance with prevalence increased in patients with OHS (26.7% vs. 8.9%; P=0.042). Forced vital capacity (FVC) and oxygen saturation (SpO2) cut-offs demonstrated high specificity (96.8%) but low sensitivity (13.3%) to diagnosed hypercapnia. Fifty percent of the patients with hypercapnia required bi-level ventilation. On follow-up 44.9% of patients were compliant with therapy (>4 hours usage/night).

CONCLUSIONS

In minimally symptomatic patients living with severe and complex obesity who have an abnormal overnight oximetry, over 1 in 10 demonstrated chronic respiratory failure. Clinic spirometry and daytime SpO2 excluded those with hypercapnia. Overall adherence to prescribed therapy is low. Screening, appropriate pre-operative optimisation and peri-operative planning are important in preventing complications in this patient cohort.

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.

Profiles of Elderly Patients with Obesity Hypoventilation Syndrome in Martinique: A Single-Center Study

Obesity hypoventilation syndrome (OHS) is a form of chronic respiratory insufficiency related to obesity that affects young and old people. Age appears to be associated with poorer response to treatment by nighttime ventilation. This study aimed to describe the characteristics of elderly subjects (>65 years) with OHS compared to younger patients, with a view to adapting therapy in older individuals. We conducted a retrospective study comparing socio-demographic, clinical, functional characteristics as well as treatment and outcomes between young (<65 years) and older (65 years and older) individuals with OHS at the University Hospital of Martinique. We included 143 patients (114 women), of whom 82 were 65 years or older (57%). Charlson index was higher in the older group. Patients in ≥65 years group were less frequently obese, but more frequently had diabetes mellitus, cardiac arrythmia and arterial hypertension compared to younger patients. There was no difference in the circumstances of diagnosis or arterial blood gas at diagnosis. At follow up, partial pressure of carbon dioxide (pCO₂) was higher in ≥65 years group. Despite comparable NIV settings, apart from lower expiratory positive airway pressure (EPAP) with higher apnea-hypopnea index (AHI), patients in the ≥65-year-old group remained more frequently hypercapnic. In conclusion, over half (57%) of patients with OHS in our cohort were aged over 65 years. Older patients developed OHS at lower BMI levels than their younger counterparts, and more frequently, had comorbidities such as diabetes, hypertension and cardiac arrhythmia. Increased Charlson index, lower BMI and female sex were independent factors associated with OHS in the elderly.

Quality of life in patients with chronic respiratory failure on home mechanical ventilation

Home mechanical ventilation (HMV) is a treatment for chronic respiratory failure that has shown clinical and cost effectiveness in patients with underlying COPD, obesity-related respiratory failure and neuromuscular disease (NMD). By treating chronic respiratory failure with adequate adherence to HMV, improvement in patient-reported outcomes including health-related quality of life (HRQoL) have been evaluated using general and disease-specific quantitative, semi-qualitative and qualitative methods. However, the treatment response in terms of trajectory of change in HRQoL is not uniform across the restrictive and obstructive disease groups. In this review, the effect of HMV on HRQoL across the domains of symptom perception, physical wellbeing, mental wellbeing, anxiety, depression, self-efficacy and sleep quality in stable and post-acute COPD, rapidly progressive NMD (such as amyotrophic lateral sclerosis), inherited NMD (including Duchenne muscular dystrophy) and obesity-related respiratory failure will be discussed.

Respiratory Center Function and Its Impact in Obesity Hypoventilation Syndrome Treatment

INTRODUCTION

Patients with obesity hypoventilation syndrome (OHS) need treatment with positive pressure either with continuous (CPAP) or double pressure (NIV). The apnea-hypopnea index (AHI) is considered a key data for making therapeutic decisions. We hypothesized that HR may be an useful tool to establish different phenotypes and individualize treatment in patients with OHS. Our objective was to analyze the role of the respiratory center response to hypercapnia (HR) in the adequacy of positive airway pressure therapy.

METHOD

We included subjects with OHS treated with CPAP or NIV according to AHI and baseline pCO₂. We analyzed therapeutic effectiveness and treatment changes prioritizing CPAP if AHI>30/h. Therapy was considered adequate if it was effective after two years. HR was measured with the p0.1/pEtCO₂ ratio and its capability to select therapy was analyzed. The statistical study was performed by means comparison (Student's t) and multivariate analysis (logistic regression).

RESULTS

67 subjects were included of 68(11) years old, 37 (55%) males, initially 45 (67%) treated with NIV and 22 (33%) with CPAP, one case was excluded and in 25 (38%) the treatment was changed. Finally, CPAP was adequate for 29 subjects (44%) and NIV for 37 (56%). The CPAP group showed AHI 57/h (24) and p0.1/pEtCO₂ 0.37cmH₂O/mmHg (0.23), NIV group AHI 43/h (35) and p0.1/pEtCO₂ 0.24 (0.15) with p=0.049 and 0.006. In multivariate analysis, p0.1/pEtCO₂ (p=0.033) and AHI>30 (p=0.001) were predictors of adequate therapy.

CONCLUSION

Measuring the RH of the respiratory center helps to select the most appropriate treatment for patients with OHS.

Does one size fit all? An update on chronic ventilatory support in different respiratory illnesses

Home noninvasive ventilation (HNIV) improves outcomes in different disease categories. In this article, we discuss indications for when and how to initiate HNIV in COPD, obesity hypoventilation syndrome (OHS) and neuromuscular disorders (NMD). While in COPD, significant diurnal hypercapnia and high-intensity HNIV are essential ingredients for success, in NMD and OHS, early respiratory changes are best detected during sleep through oxy-capnography associated (or not) with respiratory polygraphy. In COPD and OHS, it is crucial to consider the coexistence of obstructive sleep apnoea because treatment with continuous positive airway pressure may be the simplest and most effective treatment that should be proposed even in hypercapnic patients as first-line therapy. In NMD, the need for continuous HNIV and eventual switching to tracheostomy ventilation makes this group's management more challenging. Achieving successful HNIV by improving quality of sleep, quality of life and keeping a good adherence to the therapy is a challenge, above all in COPD patients. In OHS patients, on top of HNIV, initiation of other interventions such as weight loss management is crucial. More resources should be invested in improving all these aspects. Telemonitoring represents a promising method to improve titration and follow-up of HNIV.

A retrospective study of the role of hypercapnia in patients with acromegaly

BACKGROUND

Acromegaly is a multisystemic disease characterized by an excessive release of growth hormone (GH) and insulin-like growth factor-1. Obstructive sleep apnea (OSA) is a common consequence of acromegaly, and hypercapnia is frequently observed in patients with acromegaly, OSA, and obesity. However, the effects of hypercapnia on acromegaly remain unknown. This study was designed to investigate whether there are differences in clinical symptoms, sleep variables, and biochemical remission after surgery for acromegaly in patients with OSA with or without hypercapnia.

METHODS

A retrospective analysis was conducted involving patients with acromegaly and OSA. The pharmacotherapy history for acromegaly before surgery, anthropometric measures, blood gas, sleep monitoring data, and biochemical assays of hypercapnic and eucapnic individuals were collected 1-2 weeks before surgery. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for failed postoperative biochemical remission.

RESULTS

In this study, 94 patients with OSA and acromegaly were included. Among them, 25 (26.6%) had hypercapnia. The hypercapnic group had higher body mass index (92% vs. 62.3%; p = 0.005) and poorer nocturnal hypoxemia index. No serological differences were found between the two groups. According to the post-surgery GH level, 52 patients (55.3%) reached biochemical remission. Univariate logistic regression analysis revealed that diabetes mellitus (odds ratio [OR], 2.59; 95% confidence interval [CI], 1.02-6.55), instead of hypercapnia (OR, 0.61; 95% CI, 0.24-1.58), was associated with lower remission rates. Patients who received pharmacotherapy for acromegaly before surgery (OR, 0.21; 95% CI, 0.06-0.79) and had higher thyroid-stimulating hormone levels (OR, 0.53; 95% CI, 0.32-0.88) were more likely to have biochemical remission after surgery. Multivariate analysis further showed that only diabetes mellitus (OR, 3.29; 95% CI, 1.15-9.46) and preoperative pharmacotherapy (OR, 0.21; 95% CI, 0.06-0.83) remained significant. Hypercapnia, hormone levels, and sleep indicators had no effect on biochemical remission after surgery.

CONCLUSIONS

Single-center evidence shows that hypercapnia alone may not be a risk factor for lower biochemical remission rates. Correcting hypercapnia does not appear to be required before surgery. More evidence is needed to further support this conclusion.

Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is a common breathing disorder in sleep in which the airways narrow or collapse during sleep, causing obstructive sleep apnea. The prevalence of OSAS continues to rise worldwide, particularly in middle-aged and elderly individuals. The mechanism of upper airway collapse is incompletely understood but is associated with several factors, including obesity, craniofacial changes, altered muscle function in the upper airway, pharyngeal neuropathy, and fluid shifts to the neck. The main characteristics of OSAS are recurrent pauses in respiration, which lead to intermittent hypoxia (IH) and hypercapnia, accompanied by blood oxygen desaturation and arousal during sleep, which sharply increases the risk of several diseases. This paper first briefly describes the epidemiology, incidence, and pathophysiological mechanisms of OSAS. Next, the alterations in relevant signaling pathways induced by IH are systematically reviewed and discussed. For example, IH can induce gut microbiota (GM) dysbiosis, impair the intestinal barrier, and alter intestinal metabolites. These mechanisms ultimately lead to secondary oxidative stress, systemic inflammation, and sympathetic activation. We then summarize the effects of IH on disease pathogenesis, including cardiocerebrovascular disorders, neurological disorders, metabolic diseases, cancer, reproductive disorders, and COVID-19. Finally, different therapeutic strategies for OSAS caused by different causes are proposed. Multidisciplinary approaches and shared decision-making are necessary for the successful treatment of OSAS in the future, but more randomized controlled trials are needed for further evaluation to define what treatments are best for specific OSAS patients.

Acute hypercapnic respiratory failure in patients with obesity hypoventilation syndrome during the COVID-19 pandemic: Four case reports

Obesity hypoventilation syndrome (OHS) can cause acute hypercapnic respiratory failure (AHRF). The onset of AHRF in four patients with OHS during the coronavirus disease 2019 (COVID-19) pandemic is reported in this study. Two men (23 and 45 years old) and two women (both 77 years old) presented to our hospital with AHRF. In the two elderly women, a prolonged supine position due to falls seemed to be the cause of AHRF. Treatment was started with bilevel positive airway pressure for all patients. While one patient died, the condition of the other three improved; they were discharged with continuous positive airway pressure. AHRF due to OHS was rarely reported in the rural region of Japan. It is suggested that increased rates of obesity due to lifestyle changes during the COVID-19 pandemic may be responsible for an increase in the prevalence of OHS-associated AHRF.

What Circuits, Masks and Filters Should Be Used in Home Non-Invasive Mechanical Ventilation

Most of the published reviews about non-invasive home ventilation mainly reflect the technical aspects of ventilators. There is much less information about the consumables most used at home. However, the choice of a good interface or tubing system can lead to physiological changes in the patient–ventilator interaction that the clinician should be aware of. These physiological changes may affect the performance of the ventilator itself, the reliability of monitoring and, of course, the comfort of the patient. The use of different circuits, masks or filters is therefore related to the concepts of rebreathing, compressible volume, instrumental dead space or leak estimation and tidal volume. Through certain bench experiments, it is possible to determine the implications that each of these elements may have in clinical practice.

Obesity in Adults: Position Statement of Polish Association for the Study on Obesity, Polish Association of Endocrinology, Polish Association of Cardiodiabetology, Polish Psychiatric Association, Section of Metabolic and Bariatric Surgery of the Association of Polish Surgeons, and the College of Family Physicians in Poland

Obesity in adults and its complications are among the most important problems of public health. The search was conducted by using PubMed/MEDLINE, Cochrane Library, Science Direct, MEDLINE, and EBSCO databases from January 2010 to December 2022 for English language meta-analyses, systematic reviews, randomized clinical trials, and observational studies from all over the world. Six main topics were defined in the joint consensus statement of the Polish Association for the Study on Obesity, the Polish Association of Endocrinology, the Polish Association of Cardio-diabetology, the Polish Psychiatric Association, the Section of Metabolic and Bariatric Surgery of the Society of Polish Surgeons, and the College of Family Physicians in Poland: (1) the definition, causes and diagnosis of obesity; (2) treatment of obesity; (3) treatment of main complications of obesity; (4) bariatric surgery and its limitations; (5) the role of primary care in diagnostics and treatment of obesity and barriers; and (6) recommendations for general practitioners, regional authorities and the Ministry of Health. This statement outlines the role of an individual and the adequate approach to the treatment of obesity: overcoming obstacles in the treatment of obesity by primary health care. The approach to the treatment of obesity in patients with its most common complications is also discussed. Attention was drawn to the importance of interdisciplinary cooperation and considering the needs of patients in increasing the long-term effectiveness of obesity management.

Comparing the influence of foot reflexology and fasting mimicking diet on quality of life and sleep quality in obesity hypoventilation syndrome

OBJECTIVES

Obesity hypoventilation syndrome is one of the most serious outcomes of obesity-related respiratory difficulties, resulting in higher healthcare costs as well as increased cardio-respiratory morbidity and mortality.

METHODS

Sixty-two males who had a high risk of obstructive sleep apnea according to the STOP-BANG Sleep Apnea Questionnaire were enrolled in the study. Their age is 50-60 years old, and they have a BMI of 35-40 kg/m², daytime hypercapnia, and sleep breathing problems. The patients were divided into two equal groups at random reflexology fasting-mimicking diet groups. Weight, height, waist, and neck circumference were assessed at the beginning of the study and after two months of the intervention. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI), which is used to evaluate sleep quality. The Maugeri Obstructive Sleep Apnea Syndrome (MOSAS) questionnaire was used to assess a patient's quality of life.

RESULTS

There was a significant change in the MOSAS and PSQI questionnaires for both groups post-intervention, as the p-value was less than 0.05. The percentage change in the MOSAS questionnaire score and PSQI questionnaire was higher in the mimic diet group than in the reflexology group. Also, the mimic diet group's weight and neck circumference were considerably reduced after the intervention, with no change in the reflexology group.

CONCLUSIONS

Reflexology and a fasting-mimicking diet were found to have a substantial impact on enhancing the quality of life and sleep in people with obesity hypoventilation syndrome.

Diagnosing sleep disordered breathing in patients with chronic pulmonary disease: which test for which patient?

Overnight polysomnography should be the first-line diagnostic test in patients with severe respiratory disease. However, if access to polysomnography is limited, overnight polygraphy can be used as an alternative first-line diagnostic. https://bit.ly/3KlmFED.

Level of Evidence of Guidelines for Perioperative Management of Patients With Obstructive Sleep Apnea: An Evaluation Using the Appraisal of Guidelines for Research and Evaluation II Tool

Currently, the quality of guidelines for the perioperative management of patients with obstructive sleep apnea (OSA) is unknown, leaving anesthesiologists to make perioperative management decisions with some degree of uncertainty. This study evaluated the quality of clinical practice guidelines regarding the perioperative management of patients with OSA. This study was reported in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search of the MedlineALL (Ovid) database was conducted from inception to February 26, 2021, for clinical practice guidelines in the English language. Quality appraisal of guidelines was evaluated using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) framework. Descriptive statistical analysis of each of the 6 domains was expressed as a percentage using the formula: (obtained score - minimum possible score)/(maximum possible score - minimum possible score). Of 192 articles identified in the search, 41 full texts were assessed for eligibility, and 10 articles were included in this review. Intraclass correlation coefficients of the AGREE II scores across the 7 evaluators for each guideline were each >0.9, suggesting that the consistency of the scores among evaluators was high. Sixty percent of recommendations were based on evidence using validated methods to grade medical literature, while the remainder were consensus based. The median and range scores of each domain were: (1) scope and purpose, 88% (60%-95%); (2) stakeholder involvement, 52% (30%-82%); (3) rigor of development, 67% (40%-90%); (4) clarity of presentation, 74% (57%-88%); (5) applicability, 46% (20%-73%); and (6) editorial independence, 67% (19%-83%). Only 4 guidelines achieved an overall score of >70%. This critical appraisal showed that many clinical practice guidelines for perioperative management of patients with OSA used validated methods to grade medical literature, such as Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) and Oxford classification, with lower scores for stakeholder involvement due to lack of engagement of patient partners and applicability domain due to lack of focus on the complete perioperative period such as postdischarge counseling. Future efforts should be directed toward establishing higher focus on the quality of evidence, stakeholder involvement, and applicability to the wider perioperative patient experience.

Arterial bicarbonate is associated with hypoxic burden and uncontrolled hypertension in obstructive sleep apnea - The ESADA cohort

OBJECTIVE

Blood bicarbonate concentration plays an important role for obstructive sleep apnea (OSA) patients to maintain acid-base balance. We investigated the association between arterial standard bicarbonate ([HCO3^-]) and nocturnal hypoxia as well as comorbid hypertension in OSA.

METHODS

A cross-sectional analysis of 3329 patients in the European Sleep Apnea Database (ESADA) was performed. Arterial blood gas analysis and lung function test were performed in conjunction with polysomnographic sleep studies. The 4% oxygen desaturation index (ODI), mean and minimum oxygen saturation (SpO₂), and percentage of time with SpO₂ below 90% (T90%) were used to reflect nocturnal hypoxic burden. Arterial hypertension was defined as a physician diagnosis of hypertension with ongoing antihypertensive medication. Hypertensive patients with SBP/DBP below or above 140/90 mmHg were classified as controlled-, uncontrolled hypertension, respectively.

RESULTS

The [HCO3^-] level was normal in most patients (average 24.0 ± 2.5 mmol/L). ODI, T90% increased whereas mean and minimum SpO₂ decreased across [HCO3^-] tertiles (ANOVA, p = 0.030, <0.001, <0.001, and <0.001, respectively). [HCO3^-] was independently associated with ODI, mean SpO₂, minimum SpO₂, and T90% after adjusting for confounders (β value [95%CI]: 1.21 [0.88-1.54], -0.16 [-0.20 to -0.11], -0.51 [-0.64 to -0.37], 1.76 [1.48-2.04], respectively, all p < 0.001). 1 mmol/L elevation of [HCO3^-] was associated with a 4% increased odds of uncontrolled hypertension (OR: 1.04 [1.01-1.08], p = 0.013).

CONCLUSION

We first demonstrated an independent association between [HCO3^-] and nocturnal hypoxic burden as well as uncontrolled hypertension in OSA patients. Bicarbonate levels as an adjunctive measure provide insight into the pathophysiology of hypertension in OSA.

Noninvasive Ventilation Automated Technologies: A Bench Evaluation of Device Responses to Sleep-Related Respiratory Events

BACKGROUND

Noninvasive ventilation (NIV) is the reference standard treatment for most situations of chronic respiratory failure. NIV settings must be titrated to both preserve upper-airway patency and control hypoventilation. Automatic adjustment of pressure support (PS) and expiratory positive airway pressure (EPAP) may facilitate the initiation and follow-up of domiciliary NIV. However, whether the automatic-adjustment algorithms embedded into current devices accurately detect, respond to, and score common sleep-related respiratory events remains unclear.

METHODS

A bench was set up to simulate central hypopnea (CH), central apnea (CA), obstructive hypopnea (OH), and obstructive apnea (OA). Four home ventilators were evaluated, with their dedicated modes for automatic PS and EPAP adjustment.

RESULTS

All 4 devices increased PS during CH, CA, and OH. However, PS adjustment varied widely in magnitude, with tidal volumes within 100 ± 20% of the target being provided by only 3 devices for CH, one for CA, and one for OH. Two devices increased EPAP for OH and 3 for OA, including one that also increased EPAP for CA. Only 2 devices scored residual hypopnea after simulated CA, and only one scored a residual event after OH. One device scored no event.

CONCLUSIONS

Current NIV devices differed markedly in their responses to, and reporting of, standardized sleep-related respiratory events. Further improvements in embedded NIV algorithms are needed to allow more widespread out-of-laboratory initiation and follow-up of NIV.

A Novel Nomogram and Online Calculator for Predicting the Risk of Obesity Hypoventilation Syndrome in Bariatric Surgery Candidates

BACKGROUND

Obesity hypoventilation syndrome (OHS) is frequently misdiagnosed and undertreated, increasing the risk of perioperative complications. We aimed to determine the predictors of OHS and to develop and validate a novel nomogram and online calculator for identifying patients at risk of OHS in bariatric surgery candidates.

METHODS

We retrospectively analyzed the data of patients undergoing bariatric surgery between March 2017 and June 2020. Predictors were identified using univariate and multivariate analyses to establish the nomogram. The discriminative ability, calibration, and clinical value of the nomograms were tested using C-statistics, calibration plots, and decision curve analysis. The nomogram was internally validated using bootstrap resampling.

RESULTS

A total of 577 patients were enrolled, and OHS was presented in 17.9% (103/577). Body mass index (BMI) (odds ratio [OR], 1.11; 95% confidence interval (CI), 1.04-1.18; p = 0.001), neck circumference (OR, 1.09; 95% CI, 1.01-1.18; p = 0.035), type 2 diabetes (T2D) (OR, 2.02; 95% CI, 1.17-3.45; p = 0.011), serum bicarbonate (OR, 1.47; 95% CI, 1.30-1.67; p < 0.001), and C-reactive protein (CRP) (OR, 1.03; 95% CI, 1.01-1.06; p = 0.017) were independent risk factors for OHS and incorporated to develop the nomogram. The nomogram revealed good discrimination, with a C-index of 0.830 (95% CI: 0.784-0.876) (0.8227 through internal validation), and good calibration. Decision curve analysis further confirmed the nomogram's clinical usefulness.

CONCLUSIONS

The novel nomogram and online calculator provided an excellent preoperative individualized prediction of OHS in patients undergoing bariatric surgery, hereby potentially assisting clinicians and surgeons in the early detection and intensive monitoring of OHS.

Cost-effectiveness of outpatient versus inpatient non-invasive ventilation setup in obesity hypoventilation syndrome: the OPIP trial

BACKGROUND

Current guidelines recommend that patients with obesity hypoventilation syndrome (OHS) are electively admitted for inpatient initiation of home non-invasive ventilation (NIV). We hypothesised that outpatient NIV setup would be more cost-effective.

METHODS

Patients with stable OHS referred to six participating European centres for home NIV setup were recruited to an open-labelled clinical trial. Patients were randomised via web-based system using stratification to inpatient setup, with standard fixed level NIV and titrated during an attended overnight respiratory study or outpatient setup using an autotitrating NIV device and a set protocol, including home oximetry. The primary outcome was cost-effectiveness at 3 months with daytime carbon dioxide (PaCO₂) as a non-inferiority safety outcome; non-inferiority margin 0.5 kPa. Data were analysed on an intention-to-treat basis. Health-related quality of life (HRQL) was measured using EQ-5D-5L (5 level EQ-5D tool) and costs were converted using purchasing power parities to £(GBP).

RESULTS

Between May 2015 and March 2018, 82 patients were randomised. Age 59±14 years, body mass index 47±10 kg/m² and PaCO₂ 6.8±0.6 kPa. Safety analysis demonstrated no difference in ∆PaCO₂ (difference -0.27 kPa, 95% CI -0.70 to 0.17 kPa). Efficacy analysis showed similar total per-patient costs (inpatient £2962±£580, outpatient £3169±£525; difference £188.20, 95% CI -£61.61 to £438.01) and similar improvement in HRQL (EQ-5D-5L difference -0.006, 95% CI -0.05 to 0.04). There were no differences in secondary outcomes.

DISCUSSION

There was no difference in medium-term cost-effectiveness, with similar clinical effectiveness, between outpatient and inpatient NIV setup. The home NIV setup strategy can be led by local resource demand and patient and clinician preference.

TRIAL REGISTRATION NUMBERS

NCT02342899 and ISRCTN51420481.

Clinical Evaluation and Management of Overlap Syndrome (OS) and Obesity Hypoventilation Syndrome (OHS)

Background and Aim: Sleep-disordered breathing (SDB) is an extremely common disorder with a high impact on morbidity and mortality. The purpose of this study was to compare overlap syndrome (OS) and obesity hypoventilation syndrome (OHS) and to highlight and understand the differences between them. Material and Methods: The study was conducted retrospectively on 132 subjects selected by consecutive sampling from those attending our unit for suspected SDB. After clinical evaluation as well as functional and sleep investigations, the population was divided according to diagnosis in OS and OHS; then, the clinical parameters of two groups were compared with different statistical analysis. Results: The subjects with OHS were younger and reported higher rated daytime sleepiness (p = 0.005). In addition, they presented more nocturnal respiratory events (apnea-hypopnea index (AHI) 63.61 ± 22.79 events·h−1 vs. AHIOS 42.21 ± 22.91 events·h−1, p < 0.0001) at the sleep investigation as worse gas exchange during sleep leading to a higher percentage of nocturnal hypoxemia (p < 0.0001). In contrast, subjects with OS had more an impaired respiratory function. With regard to night-time ventilatory therapy, more subjects with OS were effectively treated with continuous positive airway pressure (CPAP) (p = 0.011), while more OHS were treated with auto-adjusting PAP (APAP) (14% vs. 1%, p = 0.008). Conclusions: The present study tried to establish a framework for OS and OHS because proper management of the two disorders would reduce their burden on healthcare.

Obesity-associated sleep hypoventilation and increased adverse postoperative bariatric surgery outcomes in a large clinical retrospective cohort

STUDY OBJECTIVES

Although obesity hypoventilation syndrome (OHS) is associated with increased morbidity and mortality, post-bariatric surgery OHS risk remains unclear due to often nonsystematic OHS assessments.

METHODS

We leverage a clinical cohort with nocturnal CO2 monitoring during polysomnography to address the hypothesis that patients with obesity-associated sleep hypoventilation (OaSH; ie, stage II OHS) have increased adverse postoperative bariatric surgery outcomes. We retrospectively analyzed data from patients undergoing pre-bariatric surgery polysomnography at the Cleveland Clinic from 2011-2018. OaSH was defined by body mass index ≥ 30 kg/m2 and either polysomnography-based end-tidal CO2 ≥ 45 mmHg or serum bicarbonate ≥ 27 mEq/L. Outcomes considered were as follows: intensive care unit stay, intubation, tracheostomy, discharge disposition other than home or 30-day readmission individually and as a composite, and all-cause mortality. Two-sample t test or Wilcoxon rank-sum test for continuous variables and chi-square or Fisher's exact test for categorical variables were used for OaSH vs non-OaSH comparisons. All-cause mortality was compared using Kaplan-Meier estimation and Cox proportional hazards models.

RESULTS

The analytic sample (n = 1,665) was aged 45.2 ± 12 years, 20.4% were male, had a body mass index of 48.7 ± 9 kg/m2, and 63.6% were White. OaSH prevalence was 68.5%. OaSH patients were older and more likely to be male with a higher BMI, apnea-hypopnea index, and glycated hemoglobin. The composite outcome was higher in OaSH vs non-OaSH patients (18.9% vs 14.3%, P = .021). Although some individual outcomes were respectively higher in OaSH vs non-OaSH patients, differences were not statistically significant: intubation (1.5% vs 1.3%, P = .81) and 30-day readmission (13.8% vs 11.3%, P = .16). Long-term mortality (median follow-up: 22.9 months) was not significantly different between groups, likely due to overall low event rate (hazard ratio = 1.39, 95% confidence interval: 0.56, 3.42).

CONCLUSIONS

In this largest sample to date of systematically phenotyped OaSH in a bariatric surgery cohort, we identify increased postoperative morbidity in those with sleep-related hypoventilation in stage II OHS when a composite outcome was considered, but individual contributors of intubation, intensive care unit admission, and hospital length of stay were not increased. Further study is needed to identify whether perioperative treatment of OaSH improves post-bariatric surgery outcomes.

CITATION

Chindamporn P, Wang L, Bena J, et al. Obesity-associated sleep hypoventilation and increased adverse postoperative bariatric surgery outcomes in a large clinical retrospective cohort. J Clin Sleep Med. 2022;18(12):2793-2801.

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.

Stomatognathic System Changes in Obese Patients Undergoing Bariatric Surgery: A Systematic Review

Background: Obesity is a multifactorial chronic disease involving multiple organs, devices, and systems involving important changes in the stomatognathic system, such as in the orofacial muscles, temporomandibular joint, cheeks, nose, jaw, maxilla, oral cavity, lips, teeth, tongue, hard/soft palate, larynx, and pharynx. Patients with obesity indicated for bariatric surgery reportedly presented with abnormalities in the structures and function of the stomatognathic apparatus. This occurs through the accumulation of adipose tissue in the oral cavity and pharyngeal and laryngeal regions. Therefore, this systematic review aimed to elucidate the changes occurring in the stomatognathic system of patients with obesity after undergoing bariatric surgery. Method: Information was searched based on the equations developed with the descriptors obtained in DECS and MESH using the PRISMA methodology. Studies published between 2010 and October 2021 in databases including PubMed, ProQuest, Scielo, Dialnet, EBSCO, and Springer Link were considered. Results: Eighty articles met the inclusion criteria after evaluating the articles, thereby allowing for the determination of the morphophysiological correlation of the stomatognathic system with the population studied. At the morphological or structural level, changes were observed in the face, nose, cheeks, maxilla, jaw, lips, oral cavity, teeth, tongue, palate, temporomandibular joint, neck, muscles, head, shoulders, larynx, and pharynx. At the morphological level, the main changes occurred in, and the most information was obtained from, the labial structures, teeth, muscles, pharynx, and larynx. Physiological changes were in breathing, phonation, chewing, and swallowing, thereby revealing the imbalance in basic and vital functions. Conclusions: Analyzing the changes and structures of obese patients and candidates for bariatric surgery revealed that, in the preoperative period, the evidence is clear owing to the presence of a wide range of information. However, the information is more limited regarding the postoperative period; thus, further research focusing on characterization of the system postoperatively is warranted.

Leptin-mediated neural targets in obesity hypoventilation syndrome

Obesity hypoventilation syndrome (OHS) is defined as daytime hypercapnia in obese individuals in the absence of other underlying causes. In the United States, OHS is present in 10%-20% of obese patients with obstructive sleep apnea and is linked to hypoventilation during sleep. OHS leads to high cardiorespiratory morbidity and mortality, and there is no effective pharmacotherapy. The depressed hypercapnic ventilatory response plays a key role in OHS. The pathogenesis of OHS has been linked to resistance to an adipocyte-produced hormone, leptin, a major regulator of metabolism and control of breathing. Mechanisms by which leptin modulates the control of breathing are potential targets for novel therapeutic strategies in OHS. Recent advances shed light on the molecular pathways related to the central chemoreceptor function in health and disease. Leptin signaling in the nucleus of the solitary tract, retrotrapezoid nucleus, hypoglossal nucleus, and dorsomedial hypothalamus, and anatomical projections from these nuclei to the respiratory control centers, may contribute to OHS. In this review, we describe current views on leptin-mediated mechanisms that regulate breathing and CO2 homeostasis with a focus on potential therapeutics for the treatment of OHS.

Pre-operative screening for sleep disordered breathing: obstructive sleep apnoea and beyond

Sleep disordered breathing describes an important group of conditions that causes abnormal nocturnal gas exchange, with important implications in the peri-operative management plan. An understanding of the pathophysiology behind obstructive sleep apnoea and other disorders that may lead to hypoventilation can help to prevent complications. Patients with these disorders may be minimally symptomatic and it requires careful screening in the pre-operative assessment process for a diagnosis to be made. Decisions regarding initiation of therapy, such as positive airway pressure, and delay of the operation need to be carefully weighed up against the urgency of the surgical intervention. Planning of the peri-operative care, including the use of positive airway pressure therapy and appropriate post-operative monitoring, can help to avoid respiratory and cardiovascular morbidities and improve clinical outcomes.

Educational aims

To review different types of sleep disordered breathing and available screening methods in pre-operative assessment.To understand the pathophysiology behind sleep disordered breathing and how it can lead to complications in the peri-operative setting.To review the planning and treatment strategies that should be considered as part of peri-operative management.

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 prevalence of non-invasive ventilation and long-term oxygen treatment in Helsinki University Hospital area, Finland

BACKGROUND

Chronic respiratory failure (CRF) can be treated at home with non-invasive ventilation (NIV) and/or long-term oxygen (LTOT). The prevalence of these treatments is largely unknown. We aimed to clarify the prevalence and indications of the treatments, and the three-year mortality of the treated patients in the Helsinki University Hospital (HUH) area in Finland.

METHODS

In this retrospective study we analyzed the prevalence of adult CRF patients treated with NIV and/or LTOT on 1.1.2018 and followed these patients until 1.1.2021. Data collected included the underlying diagnosis, patient characteristics, information on treatment initiation and from the last follow-up visit, and mortality during the three-year follow-up. Patients with home invasive mechanical ventilation or sleep apnea were excluded.

RESULTS

On 1.1.2018, we had a total of 815 patients treated with NIV and/or LTOT in the Helsinki University Hospital (HUH) area, with a population of 1.4 million. The prevalence of NIV was 35.4 per 100,000, of LTOT 24.6 per 100,000 and of the treatments combined 60.0 per 100,000. Almost half, 44.5%, were treated with NIV, 41.0% with LTOT, and 14.4% underwent both. The most common diagnostic groups were chronic obstructive pulmonary disease (COPD) (33.3%) and obesity-hypoventilation syndrome (OHS) (26.6%). The three-year mortality in all patients was 45.2%. In the COPD and OHS groups the mortality was 61.3% and 21.2%. In NIV treated patients, the treatment durations varied from COPD patients 5.3 years to restrictive chest wall disease patients 11.4 years. The age-adjusted Charlson co-morbidity index (ACCI) median for all patients was 3.0.

CONCLUSIONS

NIV and LTOT are common treatments in CRF. The prevalence in HUH area was comparable to other western countries. As the ACCI index shows, the treated patients were fragile, with multiple co-morbidities, and their mortality was high. Treatment duration and survival vary greatly depending on the underlying diagnosis.

Hipercapnia refractaria en paciente con síndrome de obesidad-hipoventilación maligno y COVID-19. Reporte de caso y propuesta de manejo

El síndrome de obesidad-hipoventilación asociado a la COVID-19 conduce rápidamente a la insuficiencia respiratoria aguda severa con la necesidad de ventilación mecánica invasiva, convirtiéndose en un reto terapéutico hacia el personal del cuidado intensivo debido a la ausencia de estrategias ventilatorias. A continuación se expone el caso de un paciente masculino de 51 años con antecedentes de síndrome de Pickwick que presentó neumonía grave por SARS-CoV-2, el cual progresa tempranamente a un síndrome de dificultad respiratoria aguda grave requiriendo soporte mecánico ventilatorio invasivo con presión positiva y la necesidad de soporte vasoactivo, cursando además con un síndrome de obesidad-hipoventilación de fenotipo maligno. En base a lo anterior se realiza una propuesta de manejo clínico institucional basado en la literatura científica actual del síndrome de obesidad-hipoventilación y neumonía grave secundario a SARS-CoV-2. A pesar de la alta mortalidad relacionada con la COVID-19 y la dificultad presentada durante la ventilación mecánica invasiva, el desenlace final del paciente fue favorable.

Usefulness of P0.1 in the Follow-Up of Individuals With Air Trapping and Home Noninvasive Ventilation and CPAP

BACKGROUND

The ventilatory mechanics of patients with COPD and obesity-hypoventilation syndrome (OHS) are changed when there is air trapping and auto-PEEP, which increase respiratory effort. P0.1 measures the ventilatory drive and, indirectly, respiratory effort. The aim of the study was to measure P0.1 in subjects with COPD or OHS on treatment with positive pressure and to analyze their changes in P0.1 after treatment.

METHODS

With a prospective design, subjects with COPD and OHS were studied in whom positive airway pressure was applied in their treatment. P0.1 was determined at study inclusion and after 6 months of treatment.

RESULTS

A total of 88 subjects were analyzed: 56% were males, and the mean age of 65 ± 9 y old. Fifty-four (61%) had OHS, and 34 (39%) had COPD. Fifty (56%) had air trapping, with an initial P0.1 value of 3.0 ± 1.3 cm H2O compared with 2.1 ± 0.7 cm H2O for subjects who did not have air trapping (P = .001). After 6 months of treatment, subjects who had air trapping had similar P0.1 as those who did not: 2.3 ± 1.1 and 2.1 ± 1 cm H2O, respectively (P = .53). In subjects with COPD, initial P0.1 was 2.9 ± 1.4 cm H2O and at 6 months 2.2 ± 1.1 cm H2O (P = .02). In subjects with OHS, initial P0.1 was 2.4 ± 1.1 cm H2O and at 6 months 2.2 ± 1.0 cm H2O (P = .28).

CONCLUSIONS

COPD and air trapping were associated with greater P0.1 as a marker of respiratory effort. A decrease in P0.1 indicates less respiratory effort after treatment.