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

CPAP titration failure is not equivalent to long-term CPAP treatment failure in patients with obesity hypoventilation syndrome: a case series

STUDY OBJECTIVES

Medium and long-term trials comparing continuous positive airway pressure (CPAP) with noninvasive ventilation in patients with obesity hypoventilation syndrome have shown no differences in outcomes. However, it remains unclear whether CPAP therapy should be prescribed if significant hypoxemia persists during CPAP titration, despite optimization of upper airway obstructive events or if maximum CPAP pressure is reached. We aimed to examine the effects of 6 weeks of home CPAP therapy on gas exchange in patients with obesity hypoventilation syndrome who failed CPAP titration due to persistent hypoxemia.

METHODS

This case series is a substudy of a randomized-controlled trial evaluating efficacy of 3 different PAP modalities in obesity hypoventilation syndrome. Patients randomized to CPAP who failed titration and were prescribed CPAP are included. CPAP failure was defined as spending more than 20% of total sleep time with oxygen saturation below 90% despite adequate resolution of apneas and hypopneas. Follow-up data included in-laboratory polysomnogram on prescribed CPAP after 6 weeks of home CPAP therapy.

RESULTS

Three of seven participants (43%) randomized to CPAP failed CPAP titration. All were morbidly obese, had severe OSA (apnea-hypopnea index > 90 events/h) and severe sleep hypoxemia (percentage of total sleep time with oxygen saturation < 90% [T90] = 60-89%). Hypoxemia (T90: 43-67%, T80: 0-31%, and T70: 0-11%) and hypercapnia (transcutaneous pressure of CO₂ levels > 50 mm Hg) persisted during CPAP titration polysomnogram. The final polysomnogram after 6 weeks of adherent home CPAP therapy showed effective control of obstructive sleep apnea. Hypoventilation and hypoxemia severity decreased significantly in all 3 participants.

CONCLUSIONS

Our data suggest that CPAP titration failure does not equal CPAP treatment failure.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: AVAPS-AE Efficacy Study; URL: https://clinicaltrials.gov/ct2/show/NCT01368614; Identifier: NCT01368614.

A network meta-analysis of different positive airway pressure interventions in obesity hypoventilation syndrome

Continuous positive airway pressure (CPAP) and different types of non-invasive ventilation (NIV) have been studied in obesity hypoventilation syndrome such as bi-level PAP with back-up rate (BPAP-BUR), BPAP without BUR, and the new hybrid devices that target a pre-set volume by adjustment of pressure support (VT-PS). Although several studies have compared one PAP intervention with the other, none has compared all four in a head-to-head design, which formed the basis of this network meta-analysis. PubMed and Web of Science were searched for potentially includable randomised active comparator trials. Changes in partial pressure of carbon dioxide (PaCO2 ) and Epworth Sleepiness Score (ESS) were the primary outcomes of interest. Network meta-analysis was done in R program using the 'frequentist' framework. A total of seven trials were included. Only VT-PS and BPAP-BUR showed statistically significant reductions in PaCO2 compared to control, with no significant inter-PAP differences except for the comparison between VT-PS and CPAP. Only VT-PS showed a statistically significant improvement in ESS as compared to control, with no other significant inter-PAP differences. P-score ranking (based on effect size and standard errors) and Hasse diagram ranked VT-PS and BPAP as superior to other PAPs for both primary outcomes. There were no significant differences between the different PAP interventions for hospital or emergency department admissions. The results of this network meta-analysis suggest superiority of VT-PS and BPAP over other PAP interventions at least for daytime hypercapnia and subjective daytime somnolence.

Real-world effectiveness of mepolizumab in patients with severe asthma and associated comorbidities

BACKGROUND

Patients with severe asthma frequently have associated comorbidities, which can compound existing symptoms, complicating asthma management.

OBJECTIVE

To describe the real-world effectiveness of mepolizumab in patients with severe asthma stratified by common overlapping comorbidities.

METHODS

This was a retrospective analysis of patients with asthma from the MarketScan Commercial and Medicare Supplemental Database initiating mepolizumab treatment (index date). Eligible patients had more than or equal to 1 claim (excluding claims for diagnostic tests) with a diagnosis code for more than or equal to 1 of 7 comorbidities (atopic disease, nasal polyps, chronic sinusitis, obesity, respiratory infections, chronic obstructive pulmonary disease, and depression/anxiety) during the 12-month preindex baseline period; these were used to stratify patients into 7 nonmutually exclusive subgroups. Outcomes included asthma exacerbations and exacerbation-related health care resource utilization during the 12-month baseline and follow-up periods. Each patient acted as their own control.

RESULTS

Of the 639 patients included, the most common comorbidities were atopic diseases (73.2%), respiratory infections (55.6%), and chronic sinusitis (45.1%). Across all 7 comorbidity subgroups, there were significant (P < .05) reductions of 38% to 55% and 57% to 83% in exacerbations and exacerbations requiring hospitalization, respectively, during the follow-up vs baseline period, except for exacerbations requiring hospitalization in the nasal polyp subgroup, owing to the small subgroup sample size. During the follow-up vs baseline periods, mean number of oral corticosteroids claims was significantly (P < .001) reduced by 29% to 38%; 39% to 47% of patients achieved greater than or equal to 50% oral corticosteroids dose reduction. Significant reductions in exacerbation-related health care resource utilization were also observed.

CONCLUSION

Mepolizumab treatment provided real-world clinical benefits in patients.

Contemporary Concise Review 2020: Sleep

Obstructive sleep apnoea (OSA) now affects one-seventh of the world's population. Treatment of even mild OSA can improve daytime sleepiness and quality of life. Recent modifications to uvulopalatopharyngoplasty may make it a more widely applicable treatment option in selected patients with OSA. Diet and exercise have effects on sleep apnoea severity independent of weight loss. Insomnia has become increasingly common during the coronavirus disease 2019 (COVID-19) pandemic.

Obesity and Obesity Hypoventilation, Sleep Hypoventilation, and Postoperative Respiratory Failure

Obesity hypoventilation syndrome (OHS) is considered as a diagnosis in obese patients (body mass index [BMI] ≥30 kg/m2) who also have sleep-disordered breathing and awake diurnal hypercapnia in the absence of other causes of hypoventilation. Patients with OHS have a higher burden of medical comorbidities as compared to those with obstructive sleep apnea (OSA). This places patients with OHS at higher risk for adverse postoperative events. Obese patients and those with OSA undergoing elective noncardiac surgery are not routinely screened for OHS. Screening for OHS would require additional preoperative evaluation of morbidly obese patients with severe OSA and suspicion of hypoventilation or resting hypoxemia. Cautious selection of the type of anesthesia, use of apneic oxygenation with high-flow nasal cannula during laryngoscopy, better monitoring in the postanesthesia care unit (PACU) can help minimize adverse perioperative events. Among other risk-reduction strategies are proper patient positioning, especially during intubation and extubation, multimodal analgesia, and cautious use of postoperative supplemental oxygen.

Pleural Pressure Targeted Positive Airway Pressure Improves Cardiopulmonary Function in Spontaneously Breathing Patients With Obesity

BACKGROUND

Increased pleural pressure affects the mechanics of breathing of people with class III obesity (BMI > 40 kg/m²).

RESEARCH QUESTION

What are the acute effects of CPAP titrated to match pleural pressure on cardiopulmonary function in spontaneously breathing patients with class III obesity?

STUDY DESIGN AND METHODS

We enrolled six participants with BMI within normal range (control participants, group I) and 12 patients with class III obesity (group II) divided into subgroups: IIa, BMI of 40 to 50 kg/m²; and IIb, BMI of ≥ 50 kg/m². The study was performed in two phases: in phase 1, participants were supine and breathing spontaneously at atmospheric pressure, and in phase 2, participants were supine and breathing with CPAP titrated to match their end-expiratory esophageal pressure in the absence of CPAP. Respiratory mechanics, esophageal pressure, and hemodynamic data were collected, and right heart function was evaluated by transthoracic echocardiography.

RESULTS

The levels of CPAP titrated to match pleural pressure in group I, subgroup IIa, and subgroup IIb were 6 ± 2 cmH₂O, 12 ± 3 cmH₂O, and 18 ± 4 cmH₂O, respectively. In both subgroups IIa and IIb, CPAP titrated to match pleural pressure decreased minute ventilation (IIa, P = .03; IIb, P = .03), improved peripheral oxygen saturation (IIa, P = .04; IIb, P = .02), improved homogeneity of tidal volume distribution between ventral and dorsal lung regions (IIa, P = .22; IIb, P = .03), and decreased work of breathing (IIa, P < .001; IIb, P = .003) with a reduction in both the work spent to initiate inspiratory flow as well as tidal ventilation. In five hypertensive participants with obesity, BP decreased to normal range, without impairment of right heart function.

INTERPRETATION

In ambulatory patients with class III obesity, CPAP titrated to match pleural pressure decreased work of breathing and improved respiratory mechanics while maintaining hemodynamic stability, without impairing right heart function.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02523352; URL: www.clinicaltrials.gov.

Oronasal versus Nasal Masks for Non-Invasive Ventilation in COPD: A Randomized Crossover Trial

Purpose

The impact of oronasal and nasal masks on the quality of nocturnal non-invasive ventilation (NIV) needs to be clarified. This trial was designed to compare the impact of oronasal and nasal masks on the objective quality and subjective acceptance of nocturnal NIV in COPD-patients.

Patients and Methods

In a randomized crossover trial, 30 COPD-patients with well-established high-intensity NIV (mean inspiratory/expiratory positive airway pressure 26±3/5±1 cmH₂O, mean respiratory back-up rate 17±1/min) were ventilated for two consecutive nights on oronasal and nasal masks, respectively.

Results

Full polysomnography, nocturnal blood gas measurements, and subjective assessments were performed. There was a tendency towards improved sleep efficiency (primary outcome) when an oronasal mask was worn (+9.9%; 95% CI:-0.2%-20.0%; P=0.054). Sleep stages 3/4 were favored by the oronasal mask (+12.7%; 95% CI: 6.0%-19.3%; P=<0.001). Subjective assessments were comparable with the exception of items related to leakage (P<0.05 in favor of nasal masks). The mean transcutaneous PCO₂ value for oronasal masks (47.7±7.4 mmHg) was comparable to that of nasal masks (48.9±6.6 mmHg) (P=0.11). There was considerable diversity amongst individual patients in terms of sleep quality and gas exchange following mask exchange. Subjective mask preference was not associated with sleep quality, but with nocturnal dyspnea. Over 40% of patients subsequently switched to the mask that they were not previously accustomed to.

Conclusion

In general, oronasal and nasal masks are each similarly capable of successfully delivering NIV in COPD-patients. However, the individual response to different interfaces is extremely heterogeneous, while subjective mask preference is independent from objective measures, but associated with dyspnea.

Trial Registration

German Clinical Trials Registry (DRKS00007741).

The Role of Positive Airway Pressure Therapy in Adults with Obesity Hypoventilation Syndrome. A Systematic Review and Meta-Analysis

Rationale: Obesity hypoventilation syndrome (OHS) is an undesirable complication of severe obesity. Although weight loss is an accepted component of management, it is difficult to achieve and sustain the degree of weight loss necessary to reverse OHS. As such, positive airway pressure (PAP) during sleep has become the cornerstone therapy for most patients with OHS. However, the value of PAP therapy remains uncertain.Objective: To perform a systematic review to determine whether adults with OHS should be treated with PAP therapy or not.Methods: This systematic review informed an international, multidisciplinary panel of experts who had converged to develop a clinical practice guideline on OHS for the American Thoracic Society. MEDLINE, the Cochrane Library, and Embase were searched from January 1946 to March 2019 for studies that compared PAP therapy (i.e., continuous PAP or noninvasive ventilation) to no PAP therapy in patients with OHS. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach was used to appraise the quality of evidence.Results: The search identified 2,994 unique articles. The full text of 56 articles was reviewed, and 25 studies were selected, including 3 randomized trials, 12 nonrandomized comparative studies, and 10 randomized and nonrandomized studies without a comparator group. Sample size ranged from 21 to 1,527 patients. PAP was associated with increased resolution of OHS and improvements in mortality, gas exchange, daytime sleepiness, sleep quality, quality of life, and emergency department visits. Nearly half of patients experienced trivial adverse effects related to PAP therapy. Certainty in the estimated effects was low or very low for most outcomes.Conclusions: The panel made a conditional (i.e., weak) recommendation that PAP therapy during sleep be offered to patients with OHS to improve outcomes. This recommendation was based on very low-quality evidence.

Weight Loss Interventions as Treatment of Obesity Hypoventilation Syndrome. A Systematic Review

Rationale: Obesity hypoventilation syndrome (OHS) is an undesirable consequence of obesity. Weight loss is an important component of management based on clinical rationale, but the evidence supporting weight loss has not been summarized and the optimal approach has not been determined.Objectives: This systematic review informed an international, multidisciplinary panel of experts who had converged to develop a clinical practice guideline on OHS for the American Thoracic Society. The panel asked, "Should a weight loss intervention be performed in patients with OHS?"Methods: Medline, the Cochrane Library, and Embase were searched from January 1946 to March 2019 for studies that assessed weight loss interventions in obese adults with confirmed OHS, suspected OHS, or hypercapnia. The quality of the evidence was appraised using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.Results: The search identified 2,994 articles. Six studies were selected, including two randomized trials and four nonrandomized studies without a comparator. Sample size ranged from 16 to 63 subjects. The studies found that a comprehensive weight loss program (including motivational counseling, dieting, and exercise) can reduce weight by 6% to 7% but confers no clinically significant effects compared with standard care. Bariatric surgery, on the other hand, is associated with more robust weight loss (15-64.6%, depending on the type of intervention), reduction of obstructive sleep apnea severity (18-44% reduction of the apnea-hypopnea index), and improvement in gas exchange (17-20% reduction in partial pressure of carbon dioxide in the arterial blood), ultimately leading to the resolution of OHS. Moreover, daytime sleepiness and pulmonary artery pressure also improve with significant weight loss. Bariatric surgery is associated with adverse effects in roughly one-fifth of patients, but serious adverse effects are very rare. The level of certainty in the estimated effects was very low for most outcomes.Conclusions: The guideline panel for which the systematic review was performed made a conditional (i.e., weak) recommendation suggesting a weight loss intervention for patients with OHS, targeting a sustained weight loss of 25% to 30% of actual body weight. This recommendation was based on very low-quality evidence. Although the weight loss target is based on the observation that greater weight loss is associated with better outcomes, there is a need for better-quality studies to ascertain the degree of weight loss necessary to achieve improvement in clinically relevant outcomes in patients with OHS.

Evaluation and Management of Adults with Obstructive Sleep Apnea Syndrome

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

Impact of obesity on pulmonary function: current understanding and knowledge gaps

PURPOSE OF REVIEW

Obesity is an increasing world-wide public health concern. Obesity both causes respiratory symptoms and contributes to many cardiorespiratory diseases. The effects of obesity on commonly used lung function tests are reviewed.

RECENT FINDINGS

The effects of obesity on lung function are attributed both to mechanical factors and to complex metabolic effects that contribute to a pro-inflammatory state. The effects of obesity on lung function correlate with BMI and correlate even better when the distribution of excess adipose tissue is taken into account, with central obesity associated with more prominent abnormalities. Obesity is associated with marked decreases in expiratory reserve volume and functional residual capacity. Total lung capacity, residual volume, and spirometry are less affected by obesity and are generally within the normal range except with severe obesity. Obesity decreases total respiratory system compliance primarily because of decreased lung compliance, with only mild effects on chest wall compliance. Obesity is associated with impaired gas transfer with decreases in oxygenation and varied but usually mild effects on diffusing capacity for carbon monoxide, while the carbon monoxide transfer coefficient is often increased.

SUMMARY

Obesity has significant effects on lung function. The relative contribution of the mechanical effects of obesity and the production of inflammatory cytokines by adipose tissue on lung function needs further study.

Sleep-Related Breathing Disorders: When CPAP Is Not Enough

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

Long-Term Mechanical Ventilation: Recommendations of the Swiss Society of Pulmonology

Long-term mechanical ventilation is a well-established treatment for chronic hypercapnic respiratory failure (CHRF). It is aimed at improving CHRF-related symptoms, health-related quality of life, survival, and decreasing hospital admissions. In Switzerland, long-term mechanical ventilation has been increasingly used since the 1980s in hospital and home care settings. Over the years, its application has considerably expanded with accumulating evidence of beneficial effects in a broad range of conditions associated with CHRF. Most frequent indications for long-term mechanical ventilation are chronic obstructive pulmonary disease, obesity hypoventilation syndrome, neuromuscular and chest wall diseases. In the current consensus document, the Special Interest Group of the Swiss Society of Pulmonology reviews the most recent scientific literature on long-term mechanical ventilation and provides recommendations adapted to the particular setting of the Swiss healthcare system with a focus on the practice of non-invasive and invasive home ventilation in adults.

Adherence to Positive Airway Pressure Therapy in Obesity Hypoventilation Syndrome

Because of the prevalence of extreme obesity in the United States, there has been an increase in prevalence of obesity hypoventilation syndrome (OHS). There is limited information on the characteristics and pattern of positive airway pressure (PAP) adherence in patients with OHS compared with eucapnic patients with obstructive sleep apnea (OSA). This article discusses in detail the impact of PAP therapy on outcomes in patients with OHS, compares adherence between continuous PAP and noninvasive ventilation in OHS, and compares PAP adherence in patients with OHS to patients with moderate to severe OSA enrolled in clinical trials designed to improve CPAP adherence.

Surgical management of obstructive sleep apnoea: A position statement of the Australasian Sleep Association. Respirology 2020;25:1292-1308. [PMID: 33190389 PMCID: PMC7839593 DOI: 10.1111/resp.13967]

Surgery for adult obstructive sleep apnoea (OSA) plays a key role in contemporary management paradigms, most frequently as either a second‐line treatment or in a facilitatory capacity. This committee, comprising two sleep surgeons and three sleep physicians, was established to give clarity to that role and expand upon its appropriate use in Australasia. This position statement has been reviewed and approved by the Australasian Sleep Association (ASA) Clinical Committee.

Survival and end-of-life aspects among subjects on long-term noninvasive ventilation

Background

The need for noninvasive ventilation (NIV) is commonly considered a predictor of poor survival, but life expectancy may vary depending on the underlying disease. We studied the factors associated with decreased survival and end-of-life characteristics in an unselected population of subjects starting NIV.

Methods

We conducted a retrospective study including 205 subjects initiating NIV from 1/1/2012-31/12/2015 who were followed up until 31/12/2017.

Results

The median survival time was shorter in subjects needing help with activities of daily living than in independent subjects (hazard ratio (HR) for death 1.7, 95% CI 1.2–2.6, P = 0.008) and was also shorter in subjects on long-term oxygen therapy (LTOT) than in those not on LTOT (HR for death 2.8, 95% CI 1.9–4.3, P < 0.001). There was marked difference in survival according to the disease necessitating NIV, and subjects with amyotrophic lateral sclerosis or interstitial lung disease seemed to have the shortest survival. The two most common diseases resulting in the need for NIV were chronic obstructive pulmonary disease (COPD) and obesity hypoventilation syndrome (OHS). The median survival time was 4.4 years in COPD subjects, but the median survival time was not reached in subjects with OHS (HR for death COPD vs. OHS: 3.2, 95% CI 1.9–5.5, P < 0.001). Most of the deceased subjects (55.6%) died in the hospital, while only 20.0% died at home. The last hospitalization admission leading to death occurred through the emergency room in 44.4% of the subjects.

Conclusions

Survival among subjects starting NIV in this real-life study varied greatly depending on the disease and degree of functional impairment. Subjects frequently died in the hospital after admission through the emergency department. A comprehensive treatment approach with timely advance care planning is therefore needed, especially for those needing help with activities of daily living and those with both NIV and LTOT.

Obesity Hypoventilation: Traditional Versus Nontraditional Populations

Obesity hypoventilation syndrome is the most frequent cause of chronic hypoventilation and is increasingly more common with rising obesity rates. It leads to considerable morbidity and mortality, particularly when not recognized and treated adequately. Long-term nocturnal noninvasive ventilation is the mainstay of treatment but evidence suggests that CPAP may be effective in stable patients. Specific perioperative management is required to reduce complications. Some unique syndromes associated with obesity and hypoventilation include rapid-onset obesity with hypoventilation, hypothalamic, autonomic dysregulation (ROHHAD), and Prader-Willi syndrome. Congenital central hypoventilation syndrome (early or late-onset) is a genetic disorder resulting in hypoventilation. Several acquired causes of chronic central hypoventilation also exist. A high level of clinical suspicion is required to appropriately diagnose and manage affected patients.

Perioperative Care and Medication-related Hypoventilation

Cumulative evidence supports the association of adverse postoperative outcomes with obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS). Although current guidelines recommend preoperative screening for OSA and OHS, the best perioperative management pathways remain unknown. Interventions attempting to prevent complications in the postoperative period largely are consensus based and focused on enhanced monitoring, conservative measures, and specific OSA therapies, such as positive airway pressure. Until further research is available to improve the quality and strength of these recommendations, patients with known or suspected OSA and OHS should be considered at higher risk for perioperative cardiopulmonary complications.

How to ventilate obese patients in the ICU

Obesity is an important risk factor for major complications, morbidity and mortality related to intubation procedures and ventilation in the intensive care unit (ICU). The fall in functional residual capacity promotes airway closure and atelectasis formation. This narrative review presents the impact of obesity on the respiratory system and the key points to optimize airway management, noninvasive and invasive mechanical ventilation in ICU patients with obesity. Non-invasive strategies should first optimize body position with reverse Trendelenburg position or sitting position. Noninvasive ventilation (NIV) is considered as the first-line therapy in patients with obesity having a postoperative acute respiratory failure. Positive pressure pre-oxygenation before the intubation procedure is the method of reference. The use of videolaryngoscopy has to be considered by adequately trained intensivists, especially in patients with several risk factors. Regarding mechanical ventilation in patients with and without acute respiratory distress syndrome (ARDS), low tidal volume (6 ml/kg of predicted body weight) and moderate to high positive end-expiratory pressure (PEEP), with careful recruitment maneuver in selected patients, are advised. Prone positioning is a therapeutic choice in severe ARDS patients with obesity. Prophylactic NIV should be considered after extubation to prevent re-intubation. If obesity increases mortality and risk of ICU admission in the overall population, the impact of obesity on ICU mortality is less clear and several confounding factors have to be taken into account regarding the “obesity ICU paradox”.

Extubating to Noninvasive Ventilation: Noninvasive Ventilation from Intensive Care Unit to Home

Weaning to noninvasive ventilation in intensive care unit and bridging the patients to home with respiratory support is evolving as the technology of noninvasive ventilation is improving. In patients with chronic obstructive pulmonary disease exacerbation, timing of initiation of noninvasive ventilation is the key, as persistently hypercapnic patients show benefits. High-intensity pressure support seems to do better in comparison to low-intensity pressure support. In patients with obesity and hypercapnia, obesity hypoventilation cannot be ruled out especially in an inpatient setting, and it is crucial that these patients are discharged with noninvasive ventilation.

Noninvasive Ventilation versus CPAP as Initial Treatment of Obesity Hypoventilation Syndrome

Rationale: Obesity hypoventilation syndrome (OHS) is an undesirable consequence of obesity. Treatment consists of weight loss and positive airway pressure (PAP) therapy. However, the preferred mode of PAP is uncertain.Objectives: To perform a systematic review to determine whether PAP therapy should be initiated as noninvasive ventilation (NIV) or continuous PAP (CPAP) in ambulatory patients with OHS.Methods: This systematic review informed an international, multidisciplinary panel of experts who had converged to develop a clinical practice guideline on OHS for the American Thoracic Society. MEDLINE, the Cochrane Library, and Embase were searched from January 1946 to March 2019 for studies that compared initial treatment with NIV to CPAP in OHS. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to appraise the quality of evidence.Results: The search identified 2,994 potentially relevant articles, the full text of 21 articles was reviewed, and five articles were selected. The five articles included three randomized trials (one reported as two articles) and an observational study. The sample size ranged from 36 to 225 subjects. The evidence showed no differences in mortality, cardiovascular events, and healthcare resource use between patients with OHS treated with NIV or CPAP. Both PAP modalities were similarly effective in improving gas exchange, the need for supplemental oxygen, daytime sleepiness, sleep quality, quality of life, dyspnea, and sleep-disordered breathing. There was also no significant difference in adherence to NIV or CPAP therapy. Certainty in the estimated effects was low or very low for some outcomes. Therefore, the conditional recommendation was based on very low-quality evidence.Conclusions: The panel made a conditional (i.e., weak) recommendation that CPAP rather than NIV be offered as the first-line treatment to stable ambulatory patients with OHS and coexistent severe obstructive sleep apnea (OSA). The effectiveness of CPAP is similar to that of NIV, but NIV is more costly and requires more resources than CPAP. Given that approximately 70% of patients with OHS have coexistent severe OSA, this recommendation applies to the great majority of patients with stable OHS, but it should not be extrapolated to patients with OHS without severe OSA. Patients of advanced age, with poor lung function, or with greater or recent acute ventilatory failure may not respond adequately to CPAP.

Noninvasive Ventilator Devices and Modes

Noninvasive ventilation has become an increasingly common treatment strategy for patients with diverse conditions involving chronic respiratory failure. An intimate understanding of various advanced respiratory devices and modes is essential in the management of these patients. Pressure-limited modes of ventilation are more commonly used than volume modes for noninvasive ventilation owing to enhanced patient comfort and synchrony with the ventilator, as well as improved leak compensation. Common pressure modes include spontaneous/timed and pressure control, with volume-assured pressure support being an additive feature available on certain devices. Evidence guiding the optimal mode of ventilation for specific diseases is limited.

Predicting CPAP failure in patients with suspected sleep hypoventilation identified on ambulatory testing

STUDY OBJECTIVES

Home sleep apnea testing (HSAT) is commonly used to diagnose obstructive sleep apnea, but its role in identifying patients with suspected hypoventilation or predicting their response to continuous positive airway pressure (CPAP) therapy has not been assessed. The primary objective was to determine if HSAT, combined with clinical variables, could predict the failure of CPAP to correct nocturnal hypoxemia during polysomnography in a population with suspected hypoventilation. Secondary objectives were to determine if HSAT and clinical parameters could predict awake or sleep hypoventilation.

METHODS

A retrospective review was performed of 142 consecutive patients who underwent split-night polysomnography for suspected hypoventilation after clinical assessment by a sleep physician and review of HSAT. We collected quantitative indices of nocturnal hypoxemia, patient demographics, medications, pulmonary function tests, as well as arterial blood gas data from the night of the polysomnography . CPAP failure was defined as persistent obstructive sleep apnea, hypoxemia (oxygen saturation measured by pulse oximetry < 85%), or hypercapnia despite maximal CPAP.

RESULTS

Failure of CPAP was predicted by awake oxygen saturation and arterial blood gas results but not by HSAT indices of nocturnal hypoxemia. Awake oxygen saturation ≥ 94% ruled out CPAP failure, and partial pressure of oxygen measured by arterial blood gas ≥ 68 mmHg decreased the likelihood of CPAP failure significantly.

CONCLUSIONS

In patients with suspected hypoventilation based on clinical review and HSAT interpretation by a sleep physician, awake oxygen saturation measured by pulse oximetry and partial pressure of oxygen measured by arterial blood gas can reliably identify patients in whom CPAP is likely to fail. Additional research is required to determine the role of HSAT in the identification and treatment of patients with hypoventilation.

Long-term survival following initiation of home non-invasive ventilation: a European study

INTRODUCTION

Although home non-invasive ventilation (NIV) is increasingly used to manage patients with chronic ventilatory failure, there are limited data on the long-term outcome of these patients. Our aim was to report on home NIV populations and the long-term outcome from two European centres.

METHODS

Cohort analysis including all patients established on home NIV from two European centres between 2008 and 2014.

RESULTS

Home NIV was initiated in 1746 patients to treat chronic ventilatory failure caused by (1) obesity hypoventilation syndrome±obstructive sleep apnoea (OHS±OSA) (29.5%); (2) neuromuscular disease (NMD) (22.7%); and (3) obstructive airway diseases (OAD) (19.1%). Overall cohort median survival following NIV initiation was 6.6 years. Median survival varied by underlying aetiology of respiratory failure: rapidly progressive NMD 1.1 years, OAD 2.7 years, OHS±OSA >7 years and slowly progressive NMD >7 years. Multivariate analysis demonstrated higher mortality in patients with rapidly progressive NMD (HR 4.78, 95% CI 3.38 to 6.75), COPD (HR 2.25, 95% CI 1.64 to 3.10), age >60 years at initiation of home NIV (HR 2.41, 95% CI 1.92 to 3.02) and NIV initiation following an acute admission (HR 1.38, 95% CI 1.13 to 1.68). Factors associated with lower mortality were NIV adherence >4 hours per day (HR 0.64, 95% CI 0.51 to 0.79), OSA (HR 0.51, 95% CI 0.31 to 0.84) and female gender (HR 0.79, 95% CI 0.65 to 0.96).

CONCLUSION

The mortality rate following initiation of home NIV is high but varies significantly according to underlying aetiology of respiratory failure. In patients with chronic respiratory failure, initiation of home NIV following an acute admission and low levels of NIV adherence are poor prognostic features and may be amenable to intervention.

Long-term effectiveness of CPAP in patients with severe obesity-hypoventilation syndrome

PURPOSE

The optimal mode of long-term positive airway pressure (PAP) treatment for obesity-hypoventilation syndrome (OHS) is not clear. The objectives of this study were to analyze whether or not patients with severe OHS treated with continuous positive airway pressure (CPAP) remained controlled with this therapy over the long term and to investigate which variables were associated with CPAP failure and the need to switch to non-invasive ventilation (NIV).

METHODS

In a retrospective single-center study, patients admitted to the hospital because of severe OHS between 1996 and 2015 were analyzed. A multiple regression analysis was performed in order to determine which variables were associated with either CPAP success or failure to maintain long-term control.

RESULTS

Of 126 consecutive patients, 115 accepted long-term PAP treatment. CPAP or NIV treatment was prescribed according to a protocol that included overnight polysomnographic PAP titration. Follow-up time was 8.0 ± 4.8 years. At the end of this period, 29% of CPAP-treated patients had been re-assigned to NIV because of recurrence of global respiratory failure. High levels of obesity, weight gain, lower FEV1/FVC values and the need for nocturnal supplementary oxygen independently predicted CPAP failure.

CONCLUSION

CPAP therapy for severe OHS in patients who have these risk factors should be closely monitored in the long-term for possible treatment failure.

Qualifying Patients for Noninvasive Positive Pressure Ventilation Devices on Hospital Discharge

When and how do I qualify inpatients with acute on chronic hypercapnic respiratory failure for home noninvasive positive-pressure ventilation at the time of discharge? A 44-year-old woman with morbid obesity (BMI, 48) was brought to the hospital by her boyfriend for 1 day of confusion and reduced alertness. She had a history of chronic dyspnea on exertion and 10-pack-years of smoking. She also had history of well-treated diabetes and hypertension. In the ER, she was found to be somnolent but arousable and following commands appropriately. Her oxygen saturation was 86% on room air, and arterial blood gases indicated a pH of 7.16 with a Paco₂ of 87 mm Hg, a Pao₂ of 60 mm Hg, and a bicarbonate of 42 mEq/L. Chest radiograph showed mild pulmonary vascular congestion. She was started on continuous bilevel positive airway pressure and medical therapy, with clinical improvement.

Comorbidities and Readmissions in Survivors of Acute Hypercapnic Respiratory Failure

Chronic obstructive pulmonary disease (COPD) is defined by chronic airflow obstruction, but is presently considered as a complex, heterogeneous, and multicomponent disease in which comorbidities and extrapulmonary manifestations make important contributions to disease expression. COPD-related hospital readmission. In particular frequent intensive care unit (ICU) readmissions for exacerbations represent a major challenge and place a high burden on patient outcomes and health-related quality of life, as well as on the healthcare system.In this narrative review, we first address major and often undiagnosed comorbidities associated with COPD that could have an impact on hospital readmission after an index ICU admission for acute hypercapnic respiratory failure. Some guidance for treatment is discussed. Second, we present predictors of hospital and ICU readmission and discuss various strategies to reduce such events.There is a strong rationale to detect and treat major comorbidities early after index ICU admission for acute hypercapnic respiratory failure. It still remains unclear, however, if a comprehensive and holistic approach to comorbidities in frail patients surviving hypercapnic respiratory failure can efficiently reduce the readmission rate.

Telehealth, Telemedicine, and Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) telehealth management may improve initial and chronic care access, time to diagnosis and treatment, between-visit care, e-communications and e-education, workflows, costs, and therapy outcomes. OSA telehealth options may be used to replace or supplement none, some, or all steps in the evaluation, testing, treatments, and management of OSA. All telehealth steps must adhere to OSA guidelines. OSA telehealth may be adapted for continuous positive airway pressure (CPAP) and non-CPAP treatments. E-data collection enhances uses for individual and group analytics, phenotyping, testing and treatment selections, high-risk identification and targeted support, and comparative and multispecialty therapy studies.

Effectiveness of different treatments in obesity hypoventilation syndrome

Obesity hypoventilation syndrome (OHS) is an undesirable consequence of obesity, defined as daytime hypoventilation, sleep disorder breathing and obesity; during the past few years the prevalence of extreme obesity has markedly increased worldwide consequently increasing the prevalence of OHS. Patients with OHS have a lower quality of life and a higher risk of unfavourable cardiometabolic consequences. Early diagnosis and effective treatment can lead to significant improvement in patient outcomes; therefore, such data has noticeably raised interest in the management and treatment of this sleep disorder. This paper will discuss the findings on the main current treatment modalities OHS will be discussed.

Echocardiographic Changes with Positive Airway Pressure Therapy in Obesity Hypoventilation Syndrome. Long-Term Pickwick Randomized Controlled Clinical Trial

Rationale: Obesity hypoventilation syndrome (OHS) has been associated with cardiac dysfunction. However, randomized trials assessing the impact of long-term noninvasive ventilation (NIV) or continuous positive airway pressure (CPAP) on cardiac structure and function assessed by echocardiography are lacking.Objectives: In a prespecified secondary analysis of the largest multicenter randomized controlled trial of OHS (Pickwick Project; N = 221 patients with OHS and coexistent severe obstructive sleep apnea), we compared the effectiveness of three years of NIV and CPAP on structural and functional echocardiographic changes.Methods: At baseline and annually during three sequential years, patients underwent transthoracic two-dimensional and Doppler echocardiography. Echocardiographers at each site were blinded to the treatment allocation. Statistical analysis was performed using a linear mixed-effects model with a treatment group and repeated measures interaction to determine the differential effect between CPAP and NIV.Measurements and Main Results: A total of 196 patients were analyzed: 102 were treated with CPAP and 94 were treated with NIV. Systolic pulmonary artery pressure decreased from 40.5 ± 1.47 mm Hg at baseline to 35.3 ± 1.33 mm Hg at three years with CPAP, and from 41.5 ± 1.56 mm Hg to 35.5 ± 1.42 with NIV (P < 0.0001 for longitudinal intragroup changes for both treatment arms). However, there were no significant differences between groups. NIV and CPAP therapies similarly improved left ventricular diastolic dysfunction and reduced left atrial diameter. Both NIV and CPAP improved respiratory function and dyspnea.Conclusions: In patients with OHS who have concomitant severe obstructive sleep apnea, long-term treatment with NIV and CPAP led to similar degrees of improvement in pulmonary hypertension and left ventricular diastolic dysfunction.Clinical trial registered with www.clinicaltrials.gov (NCT01405976).

The Effect of Hospital Discharge with Empiric Noninvasive Ventilation on Mortality in Hospitalized Patients with Obesity Hypoventilation Syndrome. An Individual Patient Data Meta-Analysis

Rationale: Hospitalized patients with acute-on-chronic hypercapnic respiratory failure due to obesity hypoventilation syndrome (OHS) have increased short-term mortality. It is unknown whether prescribing empiric positive airway pressure (PAP) at the time of hospital discharge reduces mortality compared with waiting for an outpatient evaluation (i.e., outpatient sleep study and outpatient PAP titration).Objectives: An international, multidisciplinary panel of experts developed clinical practice guidelines on OHS for the American Thoracic Society. The guideline panel asked whether hospitalized adult patients with acute-on-chronic hypercapnic respiratory failure suspected of having OHS, in whom the diagnosis has not yet been made, should be discharged from the hospital with or without empiric PAP treatment until the diagnosis of OHS is either confirmed or ruled out.Methods: A systematic review with individual patient data meta-analyses was performed to inform the guideline panel's recommendation. Grading of Recommendations, Assessment, Development, and Evaluation was used to summarize evidence and appraise quality.Results: The literature search identified 2,994 articles. There were no randomized trials. Ten studies met a priori study selection criteria, including two nonrandomized comparative studies and eight nonrandomized noncomparative studies. Individual patient data on hospitalized patients who survived to hospital discharge were obtained from nine of the studies and included a total of 1,162 patients (1,043 discharged with PAP and 119 discharged without PAP). Empiric noninvasive ventilation was prescribed in 91.5% of patients discharged on PAP, and the remainder received empiric continuous PAP. Discharge with PAP reduced mortality at 3 months (relative risk 0.12, 95% confidence interval 0.05-0.30, risk difference -14.5%). Certainty in the estimated effects was very low.Conclusions: Hospital discharge with PAP reduces mortality following acute-on-chronic hypercapnic respiratory failure in patients with OHS or suspected of having OHS. Well-designed clinical trials are needed to confirm this finding.

Long-term Noninvasive Ventilation in Obesity Hypoventilation Syndrome Without Severe OSA: The Pickwick Randomized Controlled Trial

BACKGROUND

Noninvasive ventilation (NIV) is an effective form of treatment in obesity hypoventilation syndrome (OHS) with severe OSA. However, there is paucity of evidence in patients with OHS without severe OSA phenotype.

RESEARCH QUESTION

Is NIV effective in OHS without severe OSA phenotype?

STUDY DESIGN AND METHODS

In this multicenter, open-label parallel group clinical trial performed at 16 sites in Spain, we randomly assigned 98 stable ambulatory patients with untreated OHS and apnea-hypopnea index < 30 events/h (ie, no severe OSA) to NIV or lifestyle modification (control group) using simple randomization through an electronic database. The primary end point was hospitalization days per year. Secondary end points included other hospital resource utilization, incident cardiovascular events, mortality, respiratory functional tests, BP, quality of life, sleepiness, and other clinical symptoms. Both investigators and patients were aware of the treatment allocation; however, treating physicians from the routine care team were not aware of patients' enrollment in the clinical trial. The study was stopped early in its eighth year because of difficulty identifying patients with OHS without severe OSA. The analysis was performed according to intention-to-treat and per-protocol principles and by adherence subgroups.

RESULTS

Forty-nine patients in the NIV group and 49 in the control group were randomized, and 48 patients in each group were analyzed. During a median follow-up of 4.98 years (interquartile range, 2.98-6.62), the mean hospitalization days per year ± SD was 2.60 ± 5.31 in the control group and 2.71 ± 4.52 in the NIV group (adjusted rate ratio, 1.07; 95% CI, 0.44-2.59; P = .882). NIV therapy, in contrast with the control group, produced significant longitudinal improvement in Paco₂, pH, bicarbonate, quality of life (Medical Outcome Survey Short Form 36 physical component), and daytime sleepiness. Moreover, per-protocol analysis showed a statistically significant difference for the time until the first ED visit favoring NIV. In the subgroup with high NIV adherence, the time until the first event of hospital admission, ED visit, and mortality was longer than in the low adherence subgroup. Adverse events were similar between arms.

INTERPRETATION

In stable ambulatory patients with OHS without severe OSA, NIV and lifestyle modification had similar long-term hospitalization days per year. A more intensive program aimed at improving NIV adherence may lead to better outcomes. Larger studies are necessary to better determine the long-term benefit of NIV in this subgroup of OHS.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01405976; URL: www.clinicaltrials.gov.

Long-Term Noninvasive Ventilation in the Geneva Lake Area: Indications, Prevalence, and Modalities

BACKGROUND

Noninvasive ventilation (NIV) is standard of care for chronic hypercapnic respiratory failure, but indications, devices, and ventilatory modes are in constant evolution.

RESEARCH QUESTION

To describe changes in prevalence and indications for NIV over a 15-year period; to provide a comprehensive report of characteristics of the population treated (age, comorbidities, and anthropometric data), mode of implementation and follow-up, devices, modes and settings used, physiological data, compliance, and data from ventilator software.

STUDY DESIGN AND METHODS

Cross-sectional observational study designed to include all subjects under NIV followed by all structures involved in NIV in the Cantons of Geneva and Vaud (1,288,378 inhabitants).

RESULTS

A total of 489 patients under NIV were included. Prevalence increased 2.5-fold since 2000 reaching 38 per 100,000 inhabitants. Median age was 71 years, with 31% being > 75 years of age. Patients had been under NIV for a median of 39 months and had an average of 3 ± 1.8 comorbidities; 55% were obese. COPD (including overlap syndrome) was the most important patient group, followed by obesity hypoventilation syndrome (OHS) (26%). Daytime Paco₂ was most often normalized. Adherence to treatment was satisfactory, with 8% only using their device < 3.5 h/d. Bilevel positive pressure ventilators in spontaneous/timed mode was the default mode (86%), with a low use of autotitrating modes. NIV was initiated electively in 50% of the population, in a hospital setting in 82%, and as outpatients in 15%.

INTERPRETATION

Use of NIV is increasing rapidly in this area, and the population treated is aging, comorbid, and frequently obese. COPD is presently the leading indication followed by OHS.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT04054570; URL: www.clinicaltrials.gov.

Multimorbidity in COPD, does sleep matter?

A good night's sleep is a prerequisite for sustainable mental and physical health. Sleep disorders, including sleep disordered breathing, insomnia and sleep related motor dysfunction (e.g., restless legs syndrome), are common in patients with chronic obstructive pulmonary disease (COPD), especially in more severe disease. COPD is commonly associated with multimorbidity, and sleep disorders as a component of this multimorbidity spectrum have a further negative impact on COPD-related comorbidities. Indeed, concomitant diseases in COPD and in obstructive sleep apnea (OSA) are similar, suggesting that the combination of COPD and OSA, the so called OSA-COPD overlap syndrome (OVS), affects patient outcomes. Potential clinically important interactions of OVS exist in cardiovascular and metabolic disease, arthritis, anxiety, depression, neurocognitive disorder and the fatigue syndrome. Correct diagnosis for recognition and treatment of sleep-related disorders in COPD is recommended. However, surprisingly limited information is available and further research and improved diagnostic tools are needed. In the absence of clear evidence, we agree with the recommendation of the Global Initiative on Chronic Obstructive Lung Disease that sleep disorders should be actively searched for and treated in patients with COPD. We believe that both aspects are important components of the holistic approach required in patients with chronic multimorbid conditions.

AVAPS-AE versus ST mode: A randomized controlled trial in patients with obesity hypoventilation syndrome

BACKGROUND AND OBJECTIVE

Average volume-assured pressure support-automated expiratory positive airway pressure (AVAPS-AE) combines an automated positive expiratory pressure to maintain upper airway patency to an automated pressure support with a targeted tidal volume. The aim of this study was to compare the effects of 2-month AVAPS-AE ventilation versus pressure support (ST) ventilation on objective sleep quality in stable patients with OHS. Secondary outcomes included arterial blood gases, health-related quality of life, daytime sleepiness, subjective sleep quality and compliance to NIV.

METHODS

This is a prospective multicentric randomized controlled trial. Consecutive OHS patients included had daytime P_a CO₂  > 6 kPa, BMI ≥ 30 kg/m² , clinical stability for more than 2 weeks and were naive from home NIV. PSG were analysed centrally by two independent experts. Primary endpoint was sleep quality improvement at 2 months.

RESULTS

Among 69 trial patients, 60 patients had successful NIV setup. Baseline and follow-up PSG were available for 26 patients randomized in the ST group and 30 in the AVAPS-AE group. At baseline, P_a CO₂ was 6.94 ± 0.71 kPa in the ST group and 6.61 ± 0.71 in the AVAPS-AE group (P = 0.032). No significant between-group difference was observed for objective sleep quality indices. Improvement in P_a CO₂ was similar between groups with a mean reduction of -0.87 kPa (95% CI: -1.12 to -0.46) in the ST group versus -0.87 kPa (95% CI: -1.14 to -0.50) in the AVAPS-AE group (P = 0.984). Mean NIV use was 6.2 h per night in both groups (P = 0.93). NIV setup duration was shorter in the AVAPS-AE group (P = 0.012).

CONCLUSION

AVAPS-AE and ST ventilation for 2 months had similar impact on sleep quality and gas exchange.