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Short, valid and easy to use tools are needed to monitor non-invasive ventilation in clinical practice and for organization of home mechanical ventilation services. The aim of this study was to develop a professional translation and cultural adaptation of the Portuguese S3 non-invasive ventilation questionnaire. 234 stable patients (128 male patients, 53.8%) with a mean age of 69.3 years under long-term home non-invasive ventilation were recruited from a single-center outpatient clinic. The most frequent diagnostic groups were obesity hypoventilation syndrome, chronic obstructive pulmonary disease and restrictive chest wall disorders. The Portuguese version of the questionnaire was obtained using translation back-translation process with two professional translators. Internal consistency for the total score was good (Cronbach’s α coefficient of 0.76) as well as for the “respiratory symptoms” and the “sleep and side effects” domains (Cronbach’s α coefficient = 0.68 and Cronbach’s α coefficient = 0.72, respectively). An exploratory factor analysis was performed leading to an explained variance of 54.6%, and resulted in 3 components. The Portuguese version of the S3-NIV questionnaire is a simple and valid tool for the routine clinical assessment of patients receiving home NIV.

Viral community-acquired pneumonia (CAP) is a potentially serious illness, particularly in adult patients with underlying chronic conditions. In addition to the most recent SARS-CoV-2, influenza, and respiratory syncytial virus (RSV) are considered the most relevant causes of viral CAP.To describe the clinical features of hospitalised adults admitted for influenza-A/B and RSV pneumonia and analyse, according to aetiology, factors associated with non-invasive ventilation (NIV) failure and in-hospital death (IHD).This was a retrospective and multi-centre study of all adults who were admitted for laboratory-confirmed influenza-A/B or RSV pneumonia, during two consecutive winter seasons (October-April 2017-2018 and 2018-2019) in three tertiary hospitals in Portugal, Italy and Cyprus.A total of 356 adults were included in the study. Influenza-A, influenza-B and RSV were deemed to cause pneumonia in 197 (55.3%), 85 (23.9%) and 74 (20.8%) patients, respectively. Patients with both obstructive sleep apnoea or obesity hypoventilation syndrome and influenza-A virus pneumonia showed a higher risk for NIV failure (odds ratio (OR) 4.66; 95% confidence interval (CI) 1.42-15.30). Patients submitted to NIV showed a higher risk for IHD, regardless of comorbidities (influenza-A OR 3.00; 95% CI 1.35-6.65, influenza-B OR 4.52; 95% CI 1.13-18.01, RSV OR 5.61; 95% CI 1.26-24.93).The increased knowledge of influenza-A/B and RSV pneumonia burden may contribute to a better management of patients with viral CAP.

Background Home mechanical ventilation (HMV) is a viable and effective strategy for patients with chronic respiratory failure (CRF). The Chilean Ministry of Health started a program for adults in 2008. Methods This study examined the following data from a prospective cohort of patients with CRF admitted to the national HMV program: characteristics, mode of admission, quality of life, time in the program and survival. Results A total of 1105 patients were included. The median age was 59 years (44–58). Women accounted for 58.1% of the sample. The average body mass index (BMI) was 34.9 (26–46) kg/m2. A total of 76.2% of patients started HMV in the stable chronic mode, while 23.8% initiated HMV in the acute mode. A total of 99 patients were transferred from the children's program. There were 1047 patients on non-invasive ventilation and 58 patients on invasive ventilation. The median baseline PaCO2 level was 58.2 (52–65) mmHg. The device usage time was 7.3 h/d (5.8–8.8), and the time in HMV was 21.6 (12.2–49.5) months. The diagnoses were COPD (35%), obesity hypoventilation syndrome (OHS; 23.9%), neuromuscular disease (NMD; 16.3%), non-cystic fibrosis bronchiectasis or tuberculosis (non-CF BC or TBC; 8.3%), scoliosis (5.9%) and amyotrophic lateral sclerosis (ALS; 5.24%). The baseline score on the Severe Respiratory Insufficiency questionnaire (SRI) was 47 (± 17.9) points and significantly improved over time. The lowest 1- and 3-year survival rates were observed in the ALS group, and the lowest 9-year survival rate was observed in the non-CF BC or TB and COPD groups. The best survival rates at 9 years were OHS, scoliosis and NMD. In 2017, there were 701 patients in the children's program and 722 in the adult´s program, with a prevalence of 10.4 per 100,000 inhabitants. Conclusion The most common diagnoses were COPD and OHS. The best survival was observed in patients with OHS, scoliosis and NMD. The SRI score improved significantly in the follow-up of patients with HMV. The prevalence of HMV was 10.4 per 100,000 inhabitants. Trial registration This study was approved by and registered at the ethics committee of North Metropolitan Health Service of Santiago, Chile (N° 018/2021).

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

The current national coverage determinations (NCDs) for noninvasive ventilation for patients with thoracic restrictive disorders, COPD, and hypoventilation syndromes were formulated in 1998. New original research, updated formal practice guidelines, and current consensus expert opinion have accrued that are in conflict with the existing NCDs. Some inconsistencies in the NCDs have been noted, and the diagnostic and therapeutic technology has also advanced in the last quarter century. Thus, these and related NCDs relevant to bilevel positive airway pressure for the treatment of OSA and central sleep apnea need to be updated to ensure the optimal health of patients with these disorders. To that end, the American College of Chest Physicians organized a multisociety (American Thoracic Society, American Academy of Sleep Medicine, and American Association for Respiratory Care) effort to engage experts in the field to: (1) identify current barriers to optimal care; (2) highlight compelling scientific evidence that would justify changes from current policies incorporating best evidence and practice; and (3) propose suggestions that would form the basis for a revised NCD in each of these 5 areas (thoracic restrictive disorders, COPD, hypoventilation syndromes, OSA, and central sleep apnea). The expert panel met during a 2-day virtual summit in October 2020 and subsequently crafted written documents designed to achieve provision of "the right device to the right patient at the right time." These documents have been endorsed by the participating societies following peer review and publication in CHEST and will be used to inform efforts to revise the current NCDs.

Acute hypercapnic respiratory failure accounts for 50 000 hospital admissions each year in the UK. This article discusses the pathophysiology and common causes of acute hypercapnic respiratory failure, and provides practical considerations for patient management in acute medical settings. Non-invasive ventilation for persistent acute hypercapnic respiratory failure is widely recognised to improve patient outcomes and reduce mortality. National audits highlight a need to improve patients' overall care and outcomes through appropriate patient selection and treatment initiation. Multidisciplinary involvement is essential, as this underpins inpatient care and follow up after hospital discharge. New non-invasive ventilation modalities may offer better patient comfort and compensate better for sleep-related changes in respiratory mechanics. Emerging therapies, such as nasal high flow, may offer an alternative treatment approach in those who cannot tolerate non-invasive ventilation, but more research is required to completely understand its effectiveness in treating acute hypercapnic respiratory failure.

Diagnosing the cause of hypoxemia and dyspnea can be complicated in complex patients with multiple comorbidities. This “Case Study in Physiology” describes an man with obesity admitted to the hospital for relapse of acute lymphoblastic leukemia, who experienced progressive hypoxemia, shortness of breath, and dyspnea on exertion during his hospitalization. After initial empirical treatment with diuresis and antibiotics failed to improve his symptoms and because an arterial blood gas measurement was not readily available, we applied a novel, recently described physiological method to estimate the arterial partial pressure of oxygen from the peripheral saturation measurement and calculate the alveolar-arterial oxygen difference to discern the source of his hypoxemia and dyspnea. Using basic physiological principles, we describe how hypoventilation, anemia, and the use of a β blocker and furosemide, collaborated to create a “perfect storm” in this patient that impaired oxygen delivery and limited utilization. This case illustrates the application of innovative physiology methodology in medicine and provides a strong rationale for continuing to integrate physiology education in medical education. NEW & NOTEWORTHY Discerning the cause of dyspnea and hypoxemia in complex patients can be difficult. We describe the “real world” application of an innovative methodology to untangle the underlying physiology in a patient with multiple comorbidities. This case further demonstrates the importance of applying physiology to interrogate the underlying cause of a patient’s symptoms when treatment based on probability fails.

Obesity-hypoventilation syndrome (OHS) is the most severe complication of obesity, being burdened by numerous cardiovascular complications and an increase in the mortality rate. Late recognition of this syndrome is common. Approaching the patient with suspicion or confirmed with OHS requires a multidisciplinary team. Positive pressure treatment remains the first line therapy, with the highest efficiency. Weight loss should be recommended in all patients. Apparently, bariatric surgery is superior to lifestyle changes. Early detection and prompt treatment are of paramount importance to minimize adverse effects, which has necessitated consideration of this article.

Background Paired-like homeobox 2B (PHOX2B) gene on chromosome 4p12 codes for a transcription factor having a role in the formation of noradrenergic neuronal circuits. Its mutations have been linked to congenital central hypoventilation syndrome (CCHS). The clinical presentation of both, obesity hypoventilation syndrome (OHS) and CCHS in adults (named late-onset central hypoventilation syndrome), is quite similar. Because of this symptomatic similarity, multifactorial causation of OHS, the mutation of PHOX2B gene was studied in patients with OHS in this study. Methods A hospital-based cross-sectional study was performed on patients diagnosed with OHS. The deoxyribonucleic acid was extracted from 2 mL of venous blood and was further amplified, specific to exon 3. The amplified products were cast and run in 2% agarose gel and then subjected to Sanger sequencing. Results Thirty patients of OHS (21 male; 9 female) were enrolled in the present study, average age being 51.7 years. The Sanger sequencing of the samples revealed no apparent areas of deletions and no apparent mutations. Conclusion Primers for exon 3 were used for amplification in thermocycler, as exon 3 is the most frequently mutated exon for PHOX2B gene, as per existing literature. The entire gene needs to be studied for mutations and the sample size needs to be increased.

The connection between obstructive sleep apnea and secondary erythrocytosis is controversial. We hypothesised that there may be a higher prevalence of erythrocytosis in patients with obesity hypoventilation syndrome (OHS) due to persistent hypoxemia. The study was a retrospective, cross-sectional review of patients with OHS derived from an established cohort of “non-invasive ventilation” patients at the Department of Sleep Medicine at the Royal Infirmary Medical Centre, Edinburgh (2004–2017). Relevant clinical data were obtained from patient records. The cohort comprised 74 patients with OHS, 44 men (60%), mean age at diagnosis 54 ± 10 years. The mean haematocrit level for the group overall was 0.44, in men 0.45, and in women 0.41. Of 11 patients with erythrocytosis (15%), 7 were men. Thirteen patients (18%) died during follow-up (2004–2017). There was a statistically significant increase in risk of death in patients with higher and lower haematocrit levels compared to that in patients with OHS who had normal haematocrits. This is the first study showing increased prevalence of erythrocytosis in OHS patients. There was a “U”-shaped correlation with mortality according to haematocrit levels.

BackgroundThe optimal interface for the delivery of home non-invasive ventilation (NIV) to treat chronic respiratory failure has not yet been determined. The aim of this individual participant data (IPD) meta-analysis was to compare the effect of nasal and oronasal masks on treatment efficacy and adherence in patients with COPD and obesity hypoventilation syndrome (OHS).MethodsWe searched Medline and Cochrane Central Register of Controlled Trials for prospective randomised controlled trials (RCTs) of at least 1 month’s duration, published between January 1994 and April 2019, that assessed NIV efficacy in patients with OHS and COPD. The main outcomes were diurnal PaCO2, PaO2 and NIV adherence (PROSPERO CRD42019132398).FindingsOf 1576 articles identified, 34 RCTs met the inclusion criteria and IPD were obtained for 18. Ten RCTs were excluded because only one type of mask was used, or mask data were missing. Data from 8 RCTs, including 290 IPD, underwent meta-analysis. Oronasal masks were used in 86% of cases. There were no differences between oronasal and nasal masks for PaCO2 (0.61 mm Hg (95% CI −2.15 to 3.38); p=0.68), PaO2 (−0.00 mm Hg (95% CI −4.59 to 4.58); p=1) or NIV adherence (0·29 hour/day (95% CI −0.74 to 1.32); p=0.58). There was no interaction between the underlying pathology and the effect of mask type on any outcome.InterpretationOronasal masks are the most used interface for the delivery of home NIV in patients with OHS and COPD; however, there is no difference in the efficacy or tolerance of oronasal or nasal masks.

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.

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.

Background Obstructive sleep apnea–hypopnea syndrome (OSAHS) is present in 80% of patients evaluated for bariatric surgery (BS). Extensive evaluation is not widely available, but treatment is mandatory for severe cases. The Snore, Tiredness, Observed apneas and Pressure - Body mass index, Age, Neck circumference and Gender (STOP-Bang) and Epworth questionnaires and neck-to-height ratio (NHtR) are accessible clinical tools to screen for sleep and metabolic disturbances, but their utility to detect severe OSAHS in patients with severe obesity has not been determined. Objectives To evaluate the cutoff point of those clinical tools that may predict severe OSAHS, confirmed by polysomnography in patients referred for BS. Setting Tertiary referral center in Mexico City. Methods We applied the STOP-Bang and Epworth questionnaires, evaluated anthropometric characteristics, and collected samples for arterial gasometry and metabolic parameters from 68 patients with severe obesity, who were then referred for polysomnography before their evaluation for BS. Results Of the 68 patients participating in the study, 67.7% were female, with a median age of 43 years (35–49 years) and a body mass index (BMI) of 45.5 kg/m2 (42.4–50.9 kg/m2; 28.3% had a BMI ≥ 50 kg/m2). A STOP-Bang cutoff >5 points had a sensitivity of 60% and specificity of 90% for detecting severe OSAHS (area under the curve [AUC] = .962); meanwhile, an NHtR >.25 had a sensitivity of 90% and specificity of 52.5% (AUC = .759). The Epworth scale score >11 points had a sensitivity of 57.1% and specificity of 83.3% (AUC = .802). Conclusion Clinical data may be useful to detect severe sleep apnea in high-risk populations, allowing for rapid referral and better use of resources.

Aljohara S Almeneessier,1,2 Salih Aleissi,1 Awad H Olaish,1 Ahmed S BaHammam1 1The University Sleep Disorders Center, Department of Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia; 2Department of Family and Community Medicine, College of Medicine, King Saud University, Riyadh, Saudi ArabiaCorrespondence: Ahmed S BaHammamMedicine, University Sleep Disorders Center, Department of Medicine, College of Medicine, King Saud University, Box 225503, Riyadh 11324, Saudi ArabiaTel +966-11-467-9495Fax +966-11-467-9179Email ashammam2@gmail.comPurpose: Long-term studies assessing positive airway pressure (PAP) therapy adherence in patients with obesity hypoventilation (OHS) are limited. The aim of this study was to assess PAP therapy adherence in Arab (Saudi) patients with OHS and an apnea-hypopnea index (AHI) > 30/h.Methods: A prospective cohort study of consecutive adult patients diagnosed with OHS between March 2010 and September 2019 was conducted. During the therapeutic sleep study, all OHS patients were started on continuous PAP (CPAP). Patients who failed to maintain oxygen saturation ≥ 88% despite the elimination of obstructive respiratory events were shifted to bi-level PAP (BPAP). Objective assessment of adherence was performed at 1, 6, and 12 months after initiating PAP therapy. We adopted the American-Thoracic-Society criteria for PAP adherence.Results: The study included 101 patients (women = 65 patients) with OHS, an AHI ≥ 30/h, and a mean age of 54.9 ± 12.7 years. Successful titration on CPAP was achieved in 64.4% of the patients and BPAP was required for 35.6% of the patients who failed CPAP titration. At the end of the study, 43.6% of the patients used PAP therapy in an acceptable manner. Adherence after 1 and 6 months was the only independent predictors of adherence at 12 months.Conclusion: PAP adherence among Saudi patients with OHS and severe obstructive sleep apnea was relatively low. Almost two-thirds of patients tolerated CPAP titration with the elimination of respiratory events and desaturation. Early adherence to PAP therapy was the only predictor of PAP therapy adherence at the end of the study.Keywords: CPAP, bi-level positive airway pressure, compliance, obstructive sleep apnea, desaturation, titration

STUDY OBJECTIVES: Blunted ventilatory responses to hypoxia and hypercapnia during resting conditions are common findings in patients with obesity hypoventilation syndrome (OHS). Exercise increases the work and oxygen cost of breathing and produces excessive carbon dioxide (CO(2)). The aim of this investigation was to study ventilatory responses to incremental exercise in patients with OHS. METHODS: Sixty-eight obese adults with OHS (n = 15), eucapnic obstructive sleep apnea (n = 26), or simple obesity (n = 27) participated in an incremental exercise test on a cycle ergometer and an in-laboratory sleep study. RESULTS: The peak oxygen uptake (peak VO(2)) and peak pulse oxygen was decreased in patients with OHS compared with patients with either obstructive sleep apnea or simple obesity. The ventilatory response to exertional metabolic demand (nadir VE/VCO(2), ∆VE/∆VCO(2) slope, and VE/VCO(2) at peak exercise) did not significantly differ among the 3 groups. Minute ventilation, tidal volume, respiratory frequency, tidal volume/respiratory frequency, and inspiratory time/total time ratio at a given work rate were comparable among the 3 groups. Among the whole cohort, apnea-hypopnea index was not independently associated with peak VO(2), and no association was found between the ∆VE/∆VCO(2) slope and resting arterial partial pressure of CO(2). CONCLUSIONS: The ventilatory response to incremental exercise is preserved in patients with OHS compared with patients with obstructive sleep apnea and simple obesity who were matched for age and body mass index. This result highlights the complexity of the respiratory control system during exercise for patients with OHS, which may be uncoupled with the ventilatory response during sleep and resting conditions. CITATION: Han T, Zhang L, Yu CY, Li YM, Wang Y, Zhang XL. Ventilatory response to exercise is preserved in patients with obesity hypoventilation syndrome. J Clin Sleep Med. 2020;16(12):2089–2098.

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.

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.

Pulmonary hypertension (PH) is prevalent in obesity hypoventilation syndrome (OHS). However, there is a paucity of data assessing pathogenic factors associated with PH. Our objective is to assess risk factors that may be involved in the pathogenesis of PH in untreated OHS.

To describe the diagnosis and management pathway of sleep-disordered breathing (SDB) in a sample of patients with severe mental illness (SMI), and to assess the feasibility and patient acceptability of overnight oximetry as a first-step screening method for detecting severe SDB in this population. The study was a retrospective audit of patients with SMI seen at a Collaborative Centre for Cardiometabolic Health in Psychosis service who were invited for overnight oximetry between November 2015 and May 2018. The adjusted oxygen desaturation index (ODI) was calculated using 4% desaturation criteria. Results were discussed with a sleep specialist and categorized into a 4-level risk probability tool for SDB. Of 91 adults consenting for overnight oximetry, 90 collected some oximetry data, though 11 of these 90 patients collected technically unsatisfactory oximetry. Thus 79/90 patients (88%) collected adequate oximetry data for at least one night. The oximetry traces suggested likely minimal obstructive sleep apnea (OSA) in 41 cases, moderate to severe OSA in 25 patients, severe OSA in 9 patients and possible obesity hypoventilation syndrome (OHS) in 4 cases. Full polysomnography was recommended for 39 patients but only one-third underwent testing. Nineteen patients were reviewed by a sleep specialist. Of the 10 patients who initiated CPAP, four were considered adherent to treatment. Home oximetry may be a pragmatic option for SDB screening in patients with SMI but reliable full diagnostic and management pathways need to be developed.

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 CO(2) 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. CITATION: Lastra AC, Masa JF, Mokhlesi B. CPAP titration failure is not equivalent to long-term CPAP treatment failure in patients with obesity hypoventilation syndrome: a case series. J Clin Sleep Med. 2020;16(11):1975–1981.

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. CITATION: Braganza MV, Hanly PJ, Fraser KL, Tsai WH, Pendharkar SR. Predicting CPAP failure in patients with suspected sleep hypoventilation identified on ambulatory testing. J Clin Sleep Med. 2020;16(9):1555–1565.

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 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

Purpose Data on hypothyroidism in patients with obesity hypoventilation syndrome (OHS) are scarce. This study assessed the prevalence of hypothyroidism among a large group of patients with OHS. Patients and Methods This was a prospective observational study of 308 consecutive patients with OHS seen between January 2002 and December 2018. Serum thyroid-stimulating hormone (TSH) and free-thyroxine (FT4) levels were measured in all patients. The OHS patients were compared with 445 patients with obstructive sleep apnoea (OSA) matched for age, sex, and body mass index (BMI). Results The OHS patients had a mean age of 55.1 ± 13.8 years and a BMI of 43.9 ± 14.8 kg/m2; apnoea hypopnea index was ≥30 events/hr in 222 (72%). Clinical hypothyroidism was diagnosed in 58 (18.8%) of the OHS patients; only two cases (0.6%) were diagnosed in the sleep disorders clinic (newly diagnosed cases). Subclinical hypothyroidism was diagnosed in 19 (6.2%) of the OHS patients based on elevated TSH and normal FT4 levels; all cases were newly diagnosed. A logistic regression model identified female sex as the only predictor of clinical hypothyroidism in OHS patients (odds ratio: 2.801 [1.386-5.662], p = 0.004). There was no significant difference in clinical hypothyroidism prevalence between the OHS and OSA patients; however, subclinical hypothyroidism was more common in OHS than in OSA patients (6.2% vs 2.9%, respectively, p = 0.03). Conclusion Clinical hypothyroidism was prevalent among patients with OHS; however, newly diagnosed cases of clinical hypothyroidism were relatively low. Female sex was the only predictor of clinical hypothyroidism.

Introduction: Around 90% of patients with OHS have coexistent obstructive sleep apnea (OSA) defined by an apnea–hypopnea index (AHI) >5 events/h, with nearly 70% having severe OSA (AHI > 30 events/h). Prevalence of OHS is between 8% and 20% in obese patients referred to sleep centers for evaluation of SDB. As prevalence of OHS in OSA patients data from Nepal is not available we planned to carry out the study and to address gaps in diagnosis and management. Methodology: This is a cross sectional observational study done in OM hospital and research centre from 2018 January to 2019 June. Awake daytime Arterial blood gas ( ABG) was obtained and patients having PaCO2 more than 45 mmHg were diagnosed as obesity hypoventilation syndrome in a recently diagnosed patients with OSA. Results: 32 patients diagnosed to have OSA and whose BMI is more than 30 were included in the study. Among 32 patients 26 (81.25%) were male and 6 (18.75) were female. Among all patients who underwent level A polysomnography 3 (12.5%) had mild OSA,4(16.66%) had moderate and 17 (53.12%) had severe OSA. 8 (25%) patients had normal diagnostic polysomnography. Among these patients 3(12.5%) who had mild OSA has BMI between 30-35,16 (66.66%) patients who had BMI between 30-35, 2 had mild 3 had moderate and 11 had severe OSA. Patients with BMI more than 40,5 (28.3%) had OSA among which 21 had moderate and 4 had severe OSA. Conclusions: As OHS is often misdiagnosed even in patients with severe obesity, we strongly recommended screening in obese patients with OSA for OHS as early recognition and effective treatment are important in improving morbidity and mortality in this group of patients.

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 Pa co 2 was most often normalized. Adherence to treatment was satisfactory, with 8% only using their device 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

Introduction Obesity-hypoventilation syndrome (OHS) is a risk factor for heart failure (HF). Some studies associate the use of non-invasive ventilation (NIV) with changes in hemodynamic parameters. Our objective was to describe the hemodynamic status of a group of patients with OHS and to study the effect of NIV. Patients and methods Patients with stable OHS treated with NIV were included in this cross-sectional repeated measurements study. Hemodynamics were measured by bioimpedance: 30 min at baseline and another 30 min on NIV. Cardiac output (CO), cardiac index, and systolic volume were measured. The CO calculated for each patient expressed as a percentage of the lower limit of normal (LLN) was taken as reference, and 2 groups were formed: patients without HF and normal CO (≥100% of LLN) and patients with HF and low CO ( Results The final sample comprised 36 patients, aged 66 (±8) years, 19 (52%) men. In 17 (46%) patients, HF was detected with a CO of 3.7 l/min (66%) compared to the group without HF, whose CO was 7 l/min (107%). After NIV, patients with HF showed improvement in CO 4.5 l/min (77%), P=.009, while the non-HF group remained unchanged, with CO 6.8 l/min (104%), P=.2. Conclusion A total of 46% of patients with stable OHS present HF; NIV improves hemodynamics and does not affect patients with normal CO.

We report an unusual case of a patient with hypertrophic obstructive cardiomyopathy, anomalous aortic origin of a coronary artery, obesity hypoventilation syndrome, and acquired long QT syndrome who was able to defy the odds of sudden cardiac death in the rarest of circumstances. (Level of Difficulty: Advanced.), Graphical abstract, We report an unusual case of a patient with hypertrophic obstructive cardiomyopathy, anomalous aortic origin of a coronary artery, obesity…

Introduction Hypercapnia is an indicator of ventilatory exhaustion. There is some disagreement regarding whether hypercapnia is also a predictor of mortality. In this prospective study, we aimed to investigate whether hypercapnia can predict in-hospital and 1-year mortality rates in patients with dyspnea or pulmonary diseases. Patients and methods All patients with dyspnea or pulmonary diseases underwent routine blood gas analysis at hospital admission. During the 12-month enrollment period, 2710 patients were enrolled, and 588 patients with hypercapnia at admission were identified. Of the 1626 normocapnic patients, 62 were randomly selected as controls. In-hospital and 1-year mortality rates were determined. Results There were significant increases in mortality rate between acute hypercapnic patients and both chronic hypercapnic patients and normocapnic controls. Their in-hospital mortality rates were 17%, 6.7% and 3.2%, respectively. Their 1-year mortality rates were 32%, 20.2% and 14.5%, respectively. The 1-year mortality rates of hypercapnic patients with different underlying diseases were 24.6% (chronic obstructive pulmonary disease), 28.4% (congestive heart disease), 1.6% (obstructive sleep apnea syndrome/obesity hypoventilation syndrome), 50.9% (pneumonia), 0% (suppressed central respiratory drive, primarily due to opiate abuse) and 22.8% (other conditions). Discussion The 1-year mortality rate of patients with acute hypercapnia at hospital admission was 32%, with significant differences compared to chronic hypercapnic patients (20.2%) and normocapnic patients (14.5%). There was a wide range of 1-year mortality rates between the hypercapnic patients with different underlying diseases.

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.

Spanish Sleep Network., [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. 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, [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.

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 Pa 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, Pa 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 Pa 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.

Background Recently, new classification criteria for obesity hypoventilation syndrome (OHS) have been described. OHS prevalence according to new criteria has not been reported in obstructive sleep apnea (OSA). Prevalence of OHS has not been previously reported from India. Methods Retrospective study was carried out in OSA patients for whom both arterial blood gases (ABG) and end-tidal CO2 (etCO2) records were available. OHS was defined according to old and new criteria. Analysis was carried out among various groups: patients without OHS (Group A), patients with sleep hypoventilation but without daytime hypercapnia (Group B) and patients with daytime hypercapnia (Group C). Results Out of 367 patients with OSA (body mass index, BMI) 31.9 ± 12.27 kg/m2), finally 128 obese OSA patients were included for analysis. Of those, 15 (5.9%, 95% confidence interval (CI) 3.5–9.4) and 45 patients (17.8%, 95% CI 13.4–22.9) fulfilled prevalence of OHS according to old and new criteria, respectively. Continuous positive airway pressure (CPAP) titration failed in 9.6%, 53.3% and 66.7% in Groups A, B, and C, respectively. For all parameters of OSA severity (apnea–hypopnea index (AHI), Nadir O2, T90) and positive airway pressure (PAP) requirements, patients in Group B were in between those in Groups A and C. Statistically significant difference was seen between Group A and Group B, and between Groups A and C, but not between Groups B and C. Conclusion One in six OSA patients and one in three obese OSA patients (BMI >30 kg/m2) have OHS according to new criteria. Since patients with isolated nocturnal hypoventilation were as sick as patients with daytime hypercapnia, screening for sleep hypoventilation should be carried out in all obese OSA patients.

Background Despite obesity hypoventilation syndrome (OHS) having more mortality than obstructive sleep apnea (OSA), the characteristics of those patients in relation to their PaCO2 have not been clarified. Aim The aim was to evaluate anthropometric, physiologic, and laboratory characteristics of patients with OHS in relation to OHS severity (according to PaCO2) and to identify OHS predictors. Patients and methods A total of 59 patients with OHS were compared with 118 BMI-matched patients with OSA as a control group. Patient demographics, arterial blood gases, polysomnographic data, and blood chemistry were compared. The patients with OHS were classified into three subgroups according to their daytime PaCO2 level: mild OHS (46 mmHg ≤PaCO2 ≤50 mmHg), moderate OHS (51 mmHg ≤PaCO2 ≤55 mmHg), and severe OHS (PaCO2≥56 mmHg). Results Patients with OHS had significantly more comorbidities, hemoglobin, and hematocrit levels, and lower PaO2 and nocturnal oxygenation parameters (baseline O2 saturation %, minimum O2%, and average O2% during sleep) than OSA group (P=0.03, 0.018, 0.007

Recent studies conclude noninvasive ventilation (NIV) as a standard first-line therapy for any respiratory failure. The efficacy of NIV in obesity is well defined. In this context, the effectiveness of NIV in extreme super-super obese patients with obesity hypoventilation syndrome is not well studied, and the usage of NIV is controversial because of rare incidence. However, identifying the right patient, right timing, right clinical expertise, correct positions, and right appropriate NIV settings can produce positive results. Therefore, we present a unique case of a 32-year-old male weighing 283 kg, with body mass index >92 kg/m2 and carbon dioxide retention, whose symptoms were worsening despite adequate conventional treatment. He received continuous NIV for 70 h using a standard protocol with close monitoring. There was improvement in the patient vitals and medical condition with significant reduction in arterial carbon dioxide tension, leading to reduction in the length of intensive care unit stay and prevention of further complications. Long-term research is encouraged to validate NIV effectiveness in this group of patients.

Background: The purpose of this guideline is to optimize evaluation and management of patients with obesity hypoventilation syndrome (OHS). Methods: A multidisciplinary panel identified and prioritized five clinical questions. The panel performed systematic reviews of available studies (up to July 2018) and followed the Grading of Recommendations, Assessment, Development, and Evaluation evidence-to-decision framework to develop recommendations. All panel members discussed and approved the recommendations. Recommendations: After considering the overall very low quality of the evidence, the panel made five conditional recommendations. We suggest that: 1) clinicians use a serum bicarbonate level

Purpose Hypercapnic respiratory failure (HRF) is a frequent cause of hospitalization and a common comorbidity in hospitalized patients. There are few studies addressing what factors might predict poor outcomes in this patient population. The purpose of the current study was to investigate characteristics and outcomes of patients hospitalized with HRF. Methods A study of patients ≥ 18 years admitted with HRF in a 1-year period. Patients with limited life expectancy related to other conditions, and those with a non-respiratory cause of HRF, were excluded. Results 202 subjects met eligibility criteria: 24% had a diagnosis of obstructive sleep apnea, 6% obesity hypoventilation, 46% chronic obstructive pulmonary disease, and 10% asthma. Fifteen (7%) died during the index admission. Forty-one patients (23%) were readmitted within 30 days: peripheral vascular disease [adjusted odds ratio (aOR) 4.78, CI 1.45–15.74] and tachycardia (aOR 2.97, CI 1.22–7.26) were associated with an increased risk of readmission. Sixty-six patients (36%) died after discharge. Risk of death was increased in older patients (aOR 1.32, CI 1.13–1.54 per 5 years), those with peripheral vascular disease (aOR 12.56, CI 2.35–67.21), higher Charlson co-morbidity index (aOR 1.39, CI 1.09–1.76), use of home oxygen (aOR 4.03, CI 1.89–8.57), and those who had been readmitted (aOR 3.07, CI 1.46–6.43). Conclusions Hospitalization for HRF is associated with a high morbidity and mortality. Our observation that home oxygen use was associated with increased mortality suggests that oxygen use could be a risk factor for death in patients with HRF.

Sleep-disordered breathing results in physiological changes that may affect various organs of the body, including the cardiovascular system. In this article, we critically review studies that have examined the prevalence and pathophysiology of pulmonary hypertension (PH) and left ventricular diastolic dysfunction (LVDD) in patients with obesity hypoventilation syndrome (OHS) and the impact of positive airway pressure therapy on cardiac function in patients with OHS. Although data regarding the prevalence of PH and LVDD in patients with OHS are limited, the available data indicate that these entities are common in patients with OHS. Previous studies have reported that the prevalence rates of PH and LVDD among patients with OHS are 50–88% and 50–70%, respectively. Several mechanisms have been proposed to explain the cardiovascular complications experienced by patients with OHS, including obesity, recurrent obstructive events, sustained hypoxemia, and systemic inflammation. However, there is limited evidence regarding the effects of positive airway pressure therapy on PH and LVDD in this patient population. Nonetheless, recent studies have suggested that positive airway pressure therapy improves pulmonary artery pressure and LVDD in patients with OHS. Available data suggest that PH and LVDD are common in patients with OHS. Recent research has suggested that positive airway pressure therapy improves PAP and LVDD in patients with OHS and severe OSA.

A. ACUTE HYPERCAPNIC RESPIRATORY FAILURE A1. Acute Exacerbation of COPD: Recommendations: NIV should be used in management of acute exacerbation of COPD in patients with acute or acute-on-chronic respiratory acidosis (pH = 7.25-7.35). (1A) NIV should be attempted in patients with acute exacerbation of COPD (pH 7.35). (2B) A2. NIV in ARF due to Chest wall deformities/Neuromuscular diseases: Recommendations: NIV may be used in patients of ARF due to chest wall deformity/Neuromuscular diseases. (PaCO2 ≥ 45) (UPP) A3. NIV in ARF due to Obesity hypoventilation syndrome (OHS): Recommendations: NIV may be used in AHRF in OHS patients when they present with acute hypercapnic or acute on chronic respiratory failure (pH 45). (3B) NIV/CPAP may be used in obese, hypercapnic patients with OHS and/or right heart failure in the absence of acidosis. (UPP) B. NIV IN ACUTE HYPOXEMIC RESPIRATORY FAILURE: B1. NIV in Acute Cardiogenic Pulmonary Oedema: Recommendations: NIV is recommended in hospital patients with ARF, due to Cardiogenic pulmonary edema. (1A). NIV should be used in patients with acute heart failure/ cardiogenic pulmonary edema, right from emergency department itself. (1B) Both CPAP and BiPAP modes are safe and effective in patients with cardiogenic pulmonary edema. (1A). However, BPAP (NIV-PS) should be preferred in cardiogenic pulmonary edema with hypercapnia. (3A) B2. NIV in acute hypoxemic respiratory failure: Recommendations: NIV may be used over conventional oxygen therapy in mild early acute hypoxemic respiratory failure (P/F ratio 200 mmHg), under close supervision. (2B) We strongly recommend against a trial of NIV in patients with acute hypoxemic failure with P/F ratio

What you need to know Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) affects around 5% of adults in the UK, while obesity hypoventilation syndrome (OHS) is estimated to affect 0.3-0.4% of the general population.1 In addition to sleepiness, OSAHS may present with a range of symptoms including insomnia and difficulties concentrating, and it can lead to hypertension and exacerbate pre-existing cardiovascular disease. People with OHS are at higher risk of cardiovascular complications and have higher mortality compared with non-obese people.2 This article summarises the most recent recommendations from the National Institute for Health and Care Excellence (NICE) guideline for obstructive sleep apnoea/hypopnoea syndrome and obesity hypoventilation syndrome in adults (over 16 years old).3 The guideline, published in August 2021, covers diagnosis and management of OSAHS, OHS, and COPD-OSAHS overlap syndrome. This guideline summary discusses only selected recommendations on OSAHS and OHS, focusing on those most relevant to primary care. NICE recommendations are based on systematic reviews of best available evidence and explicit consideration of cost effectiveness. When minimal evidence is available, recommendations are based on the guideline committee’s experience and opinion of what constitutes good practice. Evidence levels for the recommendations are given in italic in square brackets. ### Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) In this condition the upper airway is narrowed or closes during sleep when muscles relax, causing under-breathing (hypopnoea) or stopping breathing …

Introduction This study aimed to describe the cohort of obese children who were on respiratory support for obstructive sleep apnoea (OSA) or nocturnal hypoventilation in a tertiary respiratory centre and their adherence at 1 year. Methods Clinical and cardiorespiratory polygraphy data were reviewed for children with a body mass index (BMI) >25kg/m2 established on NIV for OSA (AHI>1ev/Hr) or OHS (BMI>30kg/m2 and criteria for nocturnal hypoventilation)1 from 2013–21. Children with neuro-disability were excluded. Nocturnal hypoventilation was defined as transcutaneous carbon dioxide (TCO2) >6.7kPa ≥ 25% total sleep time (TST).1 Studies less than 4 hours TST were excluded. Day time hypercapnia was defined as TCO2 >5.99kPa ≥10 minutes.1 NIV compliance was >4 hours/night use for >70% of nights.2 Results Data was obtained from 16 children (9 males, 7 females) of whom 2 children had a BMI of 25-30kg/m2, and 14 > 30Kg/m2. Baseline polygraphy data was available on 13/16 children, 8 children had OSA only, 3 had OSA and nocturnal hypoventilation and 2 had and isolated OHS. 5 children (3M, 2F, age 9.0 (4.5-16) years) had nocturnal hypoventilation and also had the highest BMI of the cohort, BMI median 36.2 (28.6-47.3) kg/m2. Daytime hypercapnia was present in 4/9 children with measurements, but only 2 had nocturnal hypoventilation. No child had a TCO2 increase >10mmHg from wake to sleep. Children were established on NIV continuous (n=11) and bilevel (n=5). Only 2/14 children with adherence data were adherent to respiratory support at 1 year. (Table 1). Discussion Assessment for complications of excess weight should include day and night-time TCO2 monitoring as OHS was evident from 5 years. Adherence to NIV is poor and intensive multi-disciplinary input may improve this. References Masa Eur Respir Rev 2019. Schwab Am J Respir Crit Care Med 2013.

Obesity hypoventilation syndrome (OHS) is a condition commonly found in severely obese patients in which they fail to breathe deeply or rapidly enough to offset the body's need for oxygen consumption and carbon dioxide release. This report presents a case of a 49-year-old super-super-morbid obese female with a body mass index (BMI) of 90 kilogram per meter squared (kg/m²), chronic obstructive pulmonary disease (COPD), and end-stage cor pulmonale, who was brought to the emergency department for altered mental status and requiring emergent airway due to respiratory failure secondary to OHS. The continued increase in rates of obesity worldwide, especially in those with BMI ≥ 50 kg/m², may lead to an increase in the incidence of OHS. With comorbidities secondary to obesity and associated complexity, this medically challenging case emphasizes the need for refined management strategies in caring for OHS in super-super-morbidly obese patients.

With increasing prevalence of obesity, the substantial contribution of obesity hypoventilation syndrome (OHS) to morbidity and mortality is likely to increase. It is therefore crucial that the condition has a clear definition to allow timely identification of patients. OHS was first described as “Pickwickian syndrome” in the 1950s; in subsequent decades, case reports did not clearly delineate between patients suffering from OHS and those suffering from obstructive sleep apnoea. In 1999, the American Academy of Sleep Medicine published a guideline that delineated the cause of daytime hypercapnia as either predominantly upper airway or predominantly hypoventilation. This was the first formal definition of OHS as the presence of daytime alveolar hypoventilation (arterial carbon dioxide tension >45 mmHg) in patients with body mass index >30 kg·m−2 in the absence of other causes of hypoventilation. This definition is reflected in the most recent guidelines published on OHS. Recent developments in defining OHS include proposed classification systems of severity and demonstrating the value of using serum bicarbonate to exclude OHS in patients with a low index of suspicion. Educational aims To provide an overview of the historical basis of the definition of obesity hypoventilation syndrome. To explain the rationale for the current definition of obesity hypoventilation syndrome. To demonstrate areas that need further investigation in defining obesity hypoventilation syndrome., Obesity hypoventilation syndrome is defined as daytime alveolar hypoventilation in obese patients in the absence of other causes of hypoventilation. Classifications of severity are now needed to target treatment at the most appropriate individuals. https://bit.ly/3yLuiL9

OBJECTIVE To evaluate the acute effects of volume-targeted non-invasive ventilation (NIV) on hemodynamic parameters assessed by impedance cardiography in patients with obesity hypoventilation syndrome (OHS). BACKGROUND Despite the well-described beneficial effects of NIV using volume-targeted pressure support ventilation modes on respiration in OHS patients, questions were raised about the impact of this treatment on the cardiovascular system. METHODS In 15 patients (10 men; mean age, 55.8±9.3 years) impedance cardiography recordings were taken at baseline, after 120 minutes while on NIV and 20 minutes after NIV termination. A repeated-measures analysis of variance was used for comparisons. RESULTS Compared to baseline, a reduction in heart rate (from 80±11 to 73±10 beats per min, p

Obesity hypoventilation syndrome (OHS) is a disorder in which patients with a body mass index ≥30 kg/m2 develop awake hypercapnia with a partial pressure of carbon dioxide ≥45 mm Hg, in the absence of other diseases that may produce alveolar hypoventilation. Additional clinical features include sleep disordered breathing, restrictive lung disease, polycythemia, hypoxemia, and an increased serum bicarbonate concentration (≥27 mEq/L). Anesthesia providers should be familiar with OHS because it is often undiagnosed, it is associated with a higher mortality rate than obstructive sleep apnea, and it is projected to increase in prevalence along with the obesity epidemic. In this case, a 33-year-old obese woman with presumed OHS developed respiratory acidosis during induction of labor. Continuous positive airway pressure treatment was initiated, but the patient continued to have hypercapnia. A cesarean delivery was recommended. The patient had baseline orthopnea due to her body habitus; thus, despite adequate labor analgesia, a cesarean delivery was completed with general endotracheal anesthesia. We believe this patient had OHS despite a serum bicarbonate 70 mm Hg, and a hemoglobin

Background Malignant obesity hypoventilation syndrome (MOHS) is described as a subtype condition of OHS, characterized by extreme obesity, obese-related hypoventilation, and multiorgan dysfunction. Because of low awareness and inadequate treatment, MOHS leads to high morbidity and mortality. Case presentation A 53-year-old man was diagnosed with MOHS evidenced by extreme obesity and multiorgan abnormalities. After taken noninvasive ventilation (NIV) treatment, he was rescued. And at the end of the six-month pulmonary rehabilitation (PR) program, improvement in terms of respiratory parameters, BMI, apnea-hypopnea index (AHI), and pulmonary hypertension were observed in the patient. Two years later, the patient was still in good condition. Conclusions This case highlights the awareness and proper use of NIV to rescue MOHS patients. Furthermore, the benefits of PR were explored in this case, which has not been considered within the therapeutic options for MOHS patients.

Coronavirus disease 2019 (COVID-19) has become a serious threat to global public health. Unfortunately, to date, there are no specific vaccines or targeted drugs, and the number of patients with positivity for systemic acute respiratory syndrome-novel coronavirus-2 infection is growing worldwide.1 Patients with COVID-19 may be at risk for liver injury, but the mechanism and clinical significance of injury remains unclear. Proposed mechanisms include direct virus-induced insults, immune-mediated damage (due to excessive inflammatory response), and drug-induced injury. COVID-19-related liver dysfunction is now gaining widespread attention; however, liver injury’s impact on the outcome of COVID-19 patients is not clearly understood. We have evaluated the impact of liver insults on the hospitalization outcome of COVID-19 patients admitted to a suburban New York safety-net hospital and would like to share our preliminary results in a Letter to the Editor instead of an Original Article for rapid dissemination to the worldwide audience. In our retrospective, unmatched, single-center analysis, we have identified the first 639 confirmed COVID-19 patients (ages ≥18 years) admitted to our facility from March 2020 to May 2020. Elevated liver-related enzymes [serum alanine aminotransferase (commonly referred to as ALT) >40 U/L, aspartate aminotransferase (commonly referred to as AST) >40 U/L, or alkaline phosphatase (commonly referred to as ALP) >120] were used to stratify patients with or without liver injury. The primary outcome was all-cause in-hospital mortality; other in-patient outcomes, including cardiac arrest, acute respiratory distress syndrome, arrhythmia, shock, and intubation rate, were also measured. The Pearson’s chi-square test and Student’s t-test were used for evaluating categorical and continuous variables, respectively. A two-step hierarchical multivariate regression model was performed to assess the risk of in-patient mortality and other hospitalization outcomes after adjusting for baseline characteristics and comorbidities. All statistical analyses were performed using SPSS® Corp. Version 22 (Armonk, NY, USA). This analysis was approved by the Institutional Review Board (IRB) of Nassau Health Care Corporation (NHCC) at Nassau University Medical Center (NUMC), under IRB reference # 20-277. Out of the total 639 COVID-19 patients, 476 (74.5%) [mean age of 58.89±15.61 years, 63.0% male] had evidence of liver injury. COVID-19 liver injury cohorts had statistically significant higher rates of all cause in-patient mortality [35.5% vs. 22.7%; adjusted odds ratio (aOR): 2.84; 95% confidence interval (CI): 1.71-4.71; p