Long-term mortality in patients with chronic obstructive pulmonary disease requiring acute non-invasive ventilation with and without obstructive sleep apnoea.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD)/obstructive sleep apnoea (OSA) overlap syndrome (OVS) is associated with higher mortality compared with COPD alone in stable outpatients. However, the prognosis of patients hospitalised with acute hypercapnic respiratory failure (ARF) is unclear. METHODS: In this retrospective cohort study, 124 patients with COPD and 44 patients with OVS were treated with positive airway pressure (PAP) for ARF and followed up for a median of 20.6 months (IQR 3.80-53.4). Patients treated in the emergency or intensive care units and did not continue PAP on the wards were excluded. We compared patient characteristics and overall survival. RESULTS: Mean (SD) age of participants was 71 (9.7) years and 51% were males. Patients with OVS had a higher prevalence of hypertension (75% vs 50.0%, p=0.004) and type 2 diabetes mellitus (45.5% vs 19.4%, p<0.001). There was no difference in arterial pH or carbon dioxide levels at presentation. On univariate analysis, mortality was lower in OVS compared with patients with COPD alone (HR 0.57, 95% CI 0.37 to 0.87). Median survival was 51.0 (95% CI 38.1 to 93.7) months in OVS and 27.7 (95% CI 16.9 to 35.1) months in COPD alone. Median survival in OVS prescribed home PAP therapy was significantly higher (59.0 months) compared with OVS not discharged on therapy (36.1 months), and to patients with COPD, irrespective of home therapy prescription (p=0.022). After adjusting for multiple known confounders, patients with OVS still appeared to have lower mortality; however, this was no longer statistically significant (HR 0.75, 95% CI 0.45 to 1.24). DISCUSSION: We found that patients with COPD and ARF requiring non-invasive ventilation may have higher mortality rates compared with patients with OVS. Patients with OVS treated with home PAP had lower mortality compared with patients not prescribed PAP on discharge. These findings suggest that patients with COPD who present with ARF may benefit from early diagnosis of OSA and initiation of long-term PAP therapy.

Interfaces for Home Noninvasive Ventilation.

The choice of interface used to deliver noninvasive ventilation (NIV) is a critical element in successfully and safely establishing home NIV in people with sleep hypoventilation syndromes. Both patient-related and equipment-related factors need to be considered when selecting an interface. Recognizing specific issues that can occur with a particular style of mask is important when troubleshooting NIV problems and attempting to minimize side effects. Access to a range of mask styles and designs to use on a rotational basis is especially important for patients using NIV on a more continuous basis, those at risk of developing pressure areas, and children.

Hypercapnia is not excluded by normoxia in neuromuscular disease patients: implications for oximetry.

Background: Pulse oximetry is widely used in the assessment of chronic respiratory failure in neuromuscular disease (NMD) patients. Chronic respiratory failure is the major cause of morbidity and mortality, necessitating early diagnosis and intervention. Guidelines suggest that an arterial blood gas (ABG) measurement is indicated if oxygen saturation (S pO2 ) is ≤94% in the absence of lung disease. However, hypercapnia with normoxia (S pO2 ≥95%) has been observed on ABGs of patients with NMD, in particular those with motor neurone disease. Methods: A single-centre retrospective audit of room-air ABGs in stable hypercapnic chronic respiratory failure patients from 1990 to 2020 was performed. Patients with parenchymal lung disease were excluded. Patients were grouped into three main categories: non-NMD, other NMD and motor neurone disease. Findings: 297 ABGs with hypercapnia from 180 patients with extrinsic restrictive lung disease were analysed. No patients with non-NMD, 54% of patients with other NMD and 36% of motor neurone disease patients demonstrated hypercapnia with normoxia (Chi-squared 61.33; p<0.001). The potential mechanism is proposed to be a difference in calculated respiratory quotient. If the alveolar-arterial gradient is assumed to be normal, the calculated respiratory quotient was significantly higher in motor neurone disease patients and other NMD patients compared with non-NMD patients (estimated marginal mean 0.99, 95% CI 0.94-1.03; 0.86 0.76-0.96; 0.73, 0.63-0.83, respectively; p<0.001) by mixed-model analysis. Interpretation: Hypercapnia is not excluded with normal oximetry in NMD patients and may be due to an elevated respiratory quotient. This has implications in the diagnosis and monitoring of respiratory insufficiency in NMD patients with oximetry alone.

Cardiac autonomic function in REM-related obstructive sleep apnoea: insights from nocturnal heart rate variability profiles.

PURPOSE: In light of the reported association between REM-related obstructive sleep apnoea (OSA) and heightened cardiovascular risk, this study aims to compare cardiac autonomic function in patients with REM-OSA and OSA independent of sleep stage. We hypothesized that REM-OSA patients would exhibit higher sympathetic cardiac modulation based on heart rate variability (HRV) profiles. METHODS: HRV was compared between the OSA group (AHI ≥ 5 events/h, n = 252) and the REM-OSA group (AHI ≥ 5 events/h, AHIREM:AHINREM ≥ 2, n = 137). Time- and frequency-domain measures of HRV were analysed during N2 and REM sleep. RESULTS: Clinical characteristics between the two test groups differed significantly, 45% of REM-OSA patients were female, with mild OSA (median, interquartile range (IQR)) AHI of 10 (7) events/h. Only 26% of the OSA cohort were female with moderate OSA (AHI = 17 (20) events/h, p < 0.001). Compared with the OSA group, the low frequency to high frequency ratio (LF:HF) and LF power were lower and HF power was higher in the REM-OSA group during N2 (LF:HF, p = 0.012; LF; p = 0.013; HF, p = 0.007) and in REM sleep (LF:HF, p = 0.002; LF, p = 0.004; HF, p < 0.001). Patient sex and OSA severity had a significant combined effect on average N to N interval, LF power, and LF:HF ratio during N2 and REM sleep (all p < 0.001). CONCLUSION: Contrary to our hypothesis, REM-OSA patients demonstrated consistently higher cardiac vagal modulation, reflecting better cardiac autonomic adaptation. These results were attributed to differences in OSA severity and sex in these two groups, both independently affecting HRV. This study emphasises the need for future research into the underlying pathophysiology of REM-OSA and the potential implications of sex and OSA severity on cardiovascular risk.

Characterisation of Symptom and Polysomnographic Profiles Associated with Cardiovascular Risk in a Sleep Clinic Population with Obstructive Sleep Apnoea.

Aim: Recent data have identified specific symptom and polysomnographic profiles associated with cardiovascular disease (CVD) in patients with obstructive sleep apnoea (OSA). Our aim was to determine whether these profiles were present at diagnosis of OSA in patients with established CVD and in those with high cardiovascular risk. Participants in the Sydney Sleep Biobank (SSB) database, aged 30-74 years, self-reported presence of CVD (coronary artery disease, cerebrovascular disease, or heart failure). In those without established CVD, the Framingham Risk Score (FRS) estimated 10-year absolute CVD risk, categorised as "low" (<6%), "intermediate" (6-20%), or "high" (>20%). Groups were compared on symptom and polysomnographic variables. Results: 629 patients (68% male; mean age 54.3 years, SD 11.6; mean BMI 32.3 kg/m2, SD 8.2) were included. CVD was reported in 12.2%. A further 14.3% had a low risk FRS, 38.8% had an intermediate risk FRS, and 34.7% had a high risk FRS. Groups differed with respect to age, sex and BMI. OSA severity increased with established CVD and increasing FRS. The symptom of waking too early was more prevalent in the higher FRS groups (p=0.004). CVD and FRS groups differed on multiple polysomnographic variables; however, none of these differences remained significant after adjusting for age, sex, and BMI. Conclusion: Higher CVD risk was associated with waking too early in patients with OSA. Polysomnographic variations between groups were explained by demographic differences. Further work is required to explore the influence of OSA phenotypic characteristics on susceptibility to CVD.

A comparison of two obesity-related hypoventilation disorders: Impact on sleep, quality of life and neurocognitive outcomes and the effects of positive airway pressure therapy.

Study Objectives: Symptom impact and neurocognitive function have not been previously compared between patients with obesity-associated hypoventilation disorders (obesity hypoventilation syndrome [OHS]) and hypoventilation in the setting of obesity and obstructive airways disease (OHAD). The aim of this study is to compare baseline sleep-related symptoms, health-related quality of life, and neurocognitive function between OHS and OHAD and the impact of PAP therapy on these outcomes. Methods: Epworth Sleepiness Scale (ESS), Pittsburgh Sleepiness Quality Index (PSQI), SF36, and various neurocognitive tests, in addition to anthropometric, polysomnography, lung function, and blood gas data from participants with OHS and participants with OHAD, were included in the analysis. These data were originally collected in their respective randomized clinical trials, comparing the efficacy of different PAP modes (bilevel PAP vs. CPAP) in resolving hypercapnia. Between groups (OHS vs OHAD), pre- and post-treatment (with 3 months of positive airway pressure) comparisons were made using linear mixed modeling. Results: 45 OHS participants (mean age 51 years old, 33% female, BMI 52 kg/m2, FER 0.81, PaCO2 54 mmHg, AHI 87/h) and 32 OHAD participants (mean age 61years old, 31% female, BMI 43kg/m2, FER 0.60, PaCO2 54 mmHg, AHI 59/h) were included in the analysis. Both OHS and OHAD had similar baseline ESS (14(5.6) vs. 12(5.4)), Global PSQI (10(3.2) vs. 11(4.8)), SF36 and neurocognitive test performances (other than OHAD had lower digit symbol substitution test performance). Treatment with PAP therapy resulted in similar ESS, Global PSQI, and SF36 improvements in both groups. Neurocognitive performance did not significantly improve after PAP therapy in either group. Conclusions: The symptom impact between two separate hypoventilation disorders (OHS and OHAD), in terms of sleepiness, sleep quality, quality of life, and cognitive function, were similar. OHS and OHAD had similar treatment responses in these parameters after 3 months of PAP therapy.Nocturnal ventilatory support in OHS.

Heart rate variability analysis in obstructive sleep apnea patients with daytime sleepiness.

STUDY OBJECTIVES: Recent studies suggest that sleepy patients with obstructive sleep apnea (OSA) are at higher risk for incident cardiovascular disease. This study assessed cardiac autonomic function in sleepy versus non-sleepy patients with OSA using heart rate variability (HRV) analysis. We hypothesized that HRV profiles of sleepy patients would indicate higher cardiovascular risk. METHODS: Electrocardiograms (ECG) derived from polysomnograms (PSG) collected by the Sydney Sleep Biobank were used to study HRV in groups of sleepy (ESS ≥ 10) and non-sleepy OSA patients (ESS < 10). HRV parameters were averaged across available ECG signals during N2 sleep. RESULTS: A total of 421 patients were evaluated, with a mean age of 54 (14) years, body mass index of 33 (9) kg/m2, apnea-hypopnea index of 21 (28) events/h, and 66% male. The sleepy group consisted of 119 patients and the non-sleepy group 302 patients. Sleepy patients exhibited lower HRV values for: root mean square successive difference (RMSSD, p = 0.028), total power (TP, p = 0.031), absolute low frequency (LF, p = 0.045), and high-frequency (HF, p = 0.010) power compared to non-sleepy patients. Sleepy patients with moderate-to-severe OSA exhibited lower HRV values for: (RMSSD, p = 0.045; TP, p = 0.052), absolute LF (p = 0.051), and HF power (p = 0.025). There were no differences in other time and frequency domain HRV markers. CONCLUSIONS: This study shows a trend toward parasympathetic withdrawal in sleepy OSA patients, particularly in moderate-to-severe cases, lending mechanistic support to the link between the sleepy phenotype and CVD risk in OSA.

Standards for the care of people with cystic fibrosis (CF); recognising and addressing CF health issues.

This is the third in a series of four papers updating the European Cystic Fibrosis Society (ECFS) standards for the care of people with CF. This paper focuses on recognising and addressing CF health issues. The guidance was produced with wide stakeholder engagement, including people from the CF community, using an evidence-based framework. Authors contributed sections, and summary statements which were reviewed by a Delphi consultation. Monitoring and treating airway infection, inflammation and pulmonary exacerbations remains important, despite the widespread availability of CFTR modulators and their accompanying health improvements. Extrapulmonary CF-specific health issues persist, such as diabetes, liver disease, bone disease, stones and other renal issues, and intestinal obstruction. These health issues require multidisciplinary care with input from the relevant specialists. Cancer is more common in people with CF compared to the general population, and requires regular screening. The CF life journey requires mental and emotional adaptation to psychosocial and physical challenges, with support from the CF team and the CF psychologist. This is particularly important when life gets challenging, with disease progression requiring increased treatments, breathing support and potentially transplantation. Planning for end of life remains a necessary aspect of care and should be discussed openly, honestly, with sensitivity and compassion for the person with CF and their family. CF teams should proactively recognise and address CF-specific health issues, and support mental and emotional wellbeing while accompanying people with CF and their families on their life journey.

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

Background: There is a significant burden of sleep disordered breathing (SDB) in patients living with severe and complex obesity undergoing pre-bariatric surgery assessment. This longitudinal observational study evaluated the burden of obesity hypoventilation syndrome (OHS) in this cohort of patients and the therapeutic compliance of patients commenced on positive airway pressure treatment. Methods: All pre-bariatric surgery patients referred to the sleep clinic for review after an abnormal screening study between 2018 and 2022 were included. We collected data on their sleep study results, anthropometrics, co-morbid medical conditions, clinical observations, spirometry and arterial blood gas (ABG). Patients commenced on therapy were followed-up longitudinally and compliance data collected via remote monitoring. Results: A total of 116 patients were included [age: mean ± standard deviation (SD) 48.8±10.8 years; body mass index (BMI) 49.2±8.5 kg/m2; Epworth Sleepiness Scale (ESS) 8.7±5.1 points]. Fifteen patients (12.9% of cohort) were diagnosed with hypercapnic respiratory failure (pH 7.40±0.02; pO2 11.00±1.04 kPa; pCO2 6.15±0.08 kPa). Compared to eucapnic obstructive sleep apnoea (OSA) patients, they were older (51.1 vs. 48.5 years; P=0.311), had a higher BMI (51.5 vs. 48.9 kg/m2; P=0.266), more likely to be female (66.7% vs. 53.5%; P=0.275) and had a higher ESS score (10.4 vs. 8.5 points; P=0.177). On binomial regression analysis insulin dependent diabetes was the only patient characteristic of significance with prevalence increased in patients with OHS (26.7% vs. 8.9%; P=0.042). Forced vital capacity (FVC) and oxygen saturation (SpO2) cut-offs demonstrated high specificity (96.8%) but low sensitivity (13.3%) to diagnosed hypercapnia. Fifty percent of the patients with hypercapnia required bi-level ventilation. On follow-up 44.9% of patients were compliant with therapy (>4 hours usage/night). Conclusions: In minimally symptomatic patients living with severe and complex obesity who have an abnormal overnight oximetry, over 1 in 10 demonstrated chronic respiratory failure. Clinic spirometry and daytime SpO2 excluded those with hypercapnia. Overall adherence to prescribed therapy is low. Screening, appropriate pre-operative optimisation and peri-operative planning are important in preventing complications in this patient cohort.

Non-invasive ventilation for people with neuromuscular disorders in Australia and New Zealand: a qualitative study of clinician perspectives.

OBJECTIVES: To explore the experiences of Australian and New Zealand clinicians with respect to care pathways, their awareness and use of non-invasive ventilation guidelines, and their perspectives on delivering quality non-invasive ventilation services to people with neuromuscular disorders. DESIGN, SETTING, PARTICIPANTS: Qualitative study; semi-structured focus groups and individual interviews with Australian and New Zealand clinicians who provide non-invasive ventilation services to people with neuromuscular disorders, recruited from participants at a 2017 sleep medicine conference. Interviews were conducted during 1 October 2017 - 31 May 2018. MAIN OUTCOME MEASURES: Major themes identified by an iterative, semantic, and inductive analysis. RESULTS: A total of 28 participants attended the four focus group sessions and five individual interviews; fourteen each from New Zealand and Australia, seventeen women and eleven men, eighteen physicians and ten other clinicians. Two major themes were identified: decision making for current practice, and resource constraints. Participants noted variable use of clinical guidelines and limited training to meet the needs of people with neuromuscular disorders who require non-invasive ventilation. They described a lack of dedicated funding, unstructured care pathways, equipment supply levels that do not meet need, low staff-to-patient ratios and staff shortages, and the inability to deliver quality multidisciplinary care. The need for clinical guidelines and service specifications was highlighted as requisite for reducing variation in clinical care. CONCLUSIONS: Systemic factors influence the needs-based provision of non-invasive ventilation for people with neuromuscular disorders. Development of clinical guidelines for Australia and New Zealand, dedicated funding for respiratory services for people with neuromuscular disorders, and specialist clinician training are important for equitable and high quality non-invasive ventilation care.

Online Education Improves Confidence in Mechanical Insufflation-Exsufflation.

BACKGROUND: Mechanical insufflation-exsufflation (MI-E) is a cough augmentation technique used to support people with an ineffective cough. MI-E can be complex due to the number of different pressure, flow, and temporal setting adjustments needed to optimize cough efficacy. Many clinicians identify inadequate training, limited experience, and low confidence as barriers to MI-E use. The purpose of this study was to determine if an online education course could improve confidence and competence in the delivery of MI-E. METHODS: An e-mail invitation to participate was disseminated to physiotherapists with a caseload that involved airway clearance for adults. The exclusion criteria were self-reported confidence and clinical expertise in MI-E. The education was created by physiotherapists with extensive experience in the provision of MI-E. The education material reviewed theoretical and practical components and was designed to take 6 h to complete. Physiotherapists were randomized to either the intervention group, who had 3 weeks of access to the education or the control group who received no intervention. Respondents in both groups completed a baseline and a post-intervention questionnaire by using visual analog scales, 0 to 10, with the primary outcomes being confidence in the prescription and confidence in the application of MI-E. Ten multiple-choice questions that covered key components of MI-E fundamentals were also completed at baseline and post-intervention. RESULTS: The intervention group had a significant improvement in the visual analog scale after the education period with a between-group difference of mean 3.6 (95% CI 4.5 to 2.7) for prescription confidence and mean 2.9 (95% CI 3.9 to 1.9) for application confidence. There was also an improvement in the multiple-choice questions with a between-group difference of mean 3.2 (95% CI 4.3 to 2). CONCLUSIONS: Access to an evidence-based online education course improved confidence in the prescription and application of MI-E, and may be a valuable tool for training clinicians in the application of MI-E.

Drivers and barriers to COVID-19 vaccination in Australians with cancer.

PURPOSE: To understand the drivers and barriers for COVID-19 vaccination in people with cancer in Australia. METHODS: A cross-sectional, online survey, distributed nationally following the establishment of community vaccination programs, wider availability of COVID-19 vaccines and emergence of new variants. Consisting of 21 questions, the survey was designed to determine the behavioural and social drivers of vaccination, participant demographics, underlying disease and treatment, and vaccination status. It was open from the 10th of August 2021 to the 7th of September 2021, recruiting people who had a previous history of cancer (diagnosed or treated in the past 5 years). RESULTS: A total of 1506 responses were included in the final analysis. Overall, 87.8% reported a positive attitude toward vaccination and 83.1% had received at least one dose of a COVID-19 vaccine. Perceived risk of COVID-19 infection (for self and others) and engagement with a trusted health professional were key drivers for vaccination, while concerns about vaccine development, safety and side effects were barriers. Concerns about vaccination mostly stemmed from a place of misinformation, rather than a broader disregard of vaccines. Just over a third (497, 34.3%) of the respondents were concerned that the vaccine would impact their cancer treatment. CONCLUSION: Overall, participants had positive attitudes toward COVID-19 vaccination and thought it was safe. Findings supported the role of health professionals and cancer organisations as trusted information providers and calls for more, credible information to help people with cancer make informed decisions about the COVID-19 vaccine.

Return to work in head and neck cancer survivors: a systematic review.

PURPOSE: Cancer survivors face higher rates of unemployment compared with individuals without a history of cancer. Compared to other cancer types, head and neck cancer (HNC) survivors face unique disease and treatment-specific issues that may limit return to work (RTW). This review aimed to determine employment outcomes of HNC survivors post-treatment and identify factors associated with RTW. METHODS: A systematic search was conducted in MEDLINE, CINAHL and PsycINFO in December 2021. Inclusion criteria included adults (≥ 18 years); completed treatment for HNC; data available on RTW post-treatment. Both quantitative and qualitative studies were considered. Studies were critically appraised and data synthesised narratively. RESULTS: Twenty-nine publications were included: 22 quantitative, four qualitative and three mixed methods. The proportion of HNC survivors who RTW ranged from 32 to 90%, with participants taking 3.6-11 months to RTW. Working in a professional role and having a supportive work environment were positively associated with RTW. CONCLUSIONS: The proportion of HNC survivors who RTW varies significantly which may be due to the heterogeneity between the studies including difference in clinical characteristics of the participants and/or sample size. Future studies that are longitudinal, adequately powered and measure a range of clinical and demographic variables are needed to better understand the RTW experience and assist development of effective RTW strategies. IMPLICATIONS FOR CANCER SURVIVORS: This review suggests potential areas for intervention, including enhanced symptom management and engaging with employers to foster supportive work environments to support RTW of HNC survivors.

Telehealth in cancer care during the COVID-19 pandemic.

INTRODUCTION: The Victorian COVID-19 Cancer Network (VCCN) Telehealth Expert Working Group aimed to evaluate the telehealth (TH) experience for cancer patients, carers and clinicians with the rapid uptake of TH in early 2020 during the COVID-19 pandemic. METHODS: We conducted a prospective multi-centre cross-sectional survey involving eight Victorian regional and metropolitan cancer services and three consumer advocacy groups. Patients or their carers and clinicians who had TH consultations between 1 July 2020 and 31 December 2020 were invited to participate in patient and clinician surveys, respectively. These surveys were opened from September to December 2020. RESULTS: The acceptability of TH via both video (82.9%) and phone (70.4%) were high though acceptability appeared to decrease in older phone TH users. Video was associated with higher satisfaction compared to phone (87.1% vs 79.7%) even though phone was more commonly used. Various themes from the qualitative surveys highlighted barriers and enablers to rapid TH implementation. DISCUSSION: The high TH acceptability supports this as a safe and effective strategy for continued care and should persist beyond the pandemic environment, where patient preferences are considered and clinically appropriate. Ongoing support to health services for infrastructure and resources, as well as expansion of reimbursement eligibility criteria for patients and health professionals, including allied health and nursing, are crucial for sustainability.

Telehealth cancer care consultations during the COVID-19 pandemic: a qualitative study of the experiences of Australians affected by cancer.

BACKGROUND: In response to the onset of the COVID-19 pandemic, telehealth was rapidly rolled out in health services across Australia including those delivering cancer care. This study aimed to understand people with cancer and carers' experiences with telehealth for cancer care during the COVID-19 pandemic and associated restrictions. METHOD: Semi-structured interviews conducted with people with cancer and carers via telephone or online video link between December 2020 and May 2021. Participants were recruited through cancer networks and social media. Interviews were transcribed and thematic analysis undertaken. RESULTS: Twenty-three patients and 5 carers were interviewed. Telephone-based appointments were most common. Responses to telehealth were influenced by existing relationships with doctors, treatment/cancer stage and type of appointment. Four themes were derived: (i) benefits, (ii) quality of care concerns, (iii) involving carers, and (iv) optimising use of telehealth. Benefits included efficiency and reduced travel. Quality of care concerns identified subthemes: transactional feel to appointments; difficulties for rapport; suitability for appointment type and adequacy for monitoring. Both patients and carers noted a lack of opportunity for carers to participate in telephone-based appointments. Aligning appointment mode (i.e. telehealth or in person) with appointment purpose and ensuring telehealth was the patient's choice were seen as essential for its ongoing use. DISCUSSION AND CONCLUSIONS: While telehealth has benefits, its potential to reduce the quality of interactions with clinicians made it less attractive for cancer patients. Patient-centred guidelines that ensure patient choice, quality communication, and alignment with appointment purpose may help to increase telehealth's utility for people affected by cancer.

A pilot randomized trial comparing CPAP vs bilevel PAP spontaneous mode in the treatment of hypoventilation disorder in patients with obesity and obstructive airway disease.

STUDY OBJECTIVES: Both obesity and airways disease can lead to chronic hypercapnic respiratory failure, which can be managed with positive airway pressure (PAP) therapy. The efficacy of PAP has been studied in obesity hypoventilation syndrome as well as in chronic hypercapnic chronic obstructive pulmonary disease patients, but not in patients where both obesity and airway obstruction coexist. This pilot study aims to compare the efficacy of continuous positive airway pressure vs bilevel positive airway pressure spontaneous mode in the treatment of hypoventilation disorder with obesity and obstructive airways disease. METHODS: We sequentially screened PAP-naïve patients with stable chronic hypercapnic respiratory failure (PaCO2 > 45 mm Hg), obesity (body mass index > 30 kg/m2), and obstructive airways disease. Participants were randomized to continuous positive airway pressure or bilevel positive airway pressure spontaneous mode treatment for 3 months. Participants were blinded to their PAP allocation. Change in awake PaCO2 was the primary endpoint. Secondary endpoints included change in lung function, daytime sleepiness, sleep quality, quality of life, PAP adherence, and neurocognitive function. RESULTS: A total of 32 individuals were randomized (mean ± SD: age 61 ± 11 years, body mass index 43 ± 7 kg/m2, PaCO2 54 ± 7 mm Hg, forced expiratory volume in 1 second 1.4 ± 0.6L, apnea-hypopnea index 59 ± 35 events/h). Sixteen participants in each PAP group were analyzed. Bilevel positive airway pressure yielded a greater improvement in PaCO2 compared to continuous positive airway pressure (9.4 mm Hg, 95% confidence interval, 4.3-15 mm Hg). There were no significant differences in PAP adherence, sleepiness, sleep quality, or neurocognitive function between the two therapies. CONCLUSIONS: Although both PAP modalities improved hypercapnic respiratory failure in this group of individuals, bilevel positive airway pressure spontaneous mode showed greater efficacy in reducing PaCO2. CLINICAL TRIAL REGISTRATION: Registry: Australian New Zealand Clinical Trials Registry; Name: Nocturnal ventilatory support in obesity hypoventilation syndrome; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12605000096651; Identifier: ACTRN12605000096651. CITATION: Zheng Y, Yee BJ, Wong K, Grunstein R, Piper A. A pilot randomized trial comparing CPAP vs bilevel PAP spontaneous mode in the treatment of hypoventilation disorder in patients with obesity and obstructive airway disease. J Clin Sleep Med. 2022;18(1):99-107.

Cardiopulmonary coupling and serum cardiac biomarkers in obesity hypoventilation syndrome and obstructive sleep apnea with morbid obesity.

STUDY OBJECTIVES: The main cause of death in patients with obesity hypoventilation syndrome (OHS) is cardiac rather than respiratory failure. Here, we investigated autonomic-respiratory coupling and serum cardiac biomarkers in patients with OHS and obstructive sleep apnea (OSA) with comparable body mass index and apnea-hypopnea index. METHODS: Cardiopulmonary coupling (CPC) and cyclic variation of heart rate analysis was performed on the electrocardiogram signal from the overnight polysomnogram. Cardiac serum biomarkers were obtained in patients with OHS and OSA with a body mass index > 40 kg/m2. Samples were obtained at baseline and after 3 months of positive airway pressure (PAP) therapy in both groups. RESULTS: Patients with OHS (n = 15) and OSA (n = 36) were recruited. No group differences in CPC, cyclic variation of heart rate, and serum biomarkers were observed at baseline and after 3 months of PAP therapy. An improvement in several CPC metrics, including the sleep apnea index, unstable sleep (low-frequency coupling and elevated low-frequency coupling narrow band), and cyclic variation of heart rate were observed in both groups with PAP use. However, distinct differences in response characteristics were noted. Elevated low-frequency coupling narrow band coupling correlated with highly sensitive troponin-T (P < .05) in the combined cohort. Baseline highly sensitive troponin-T inversely correlated with awake oxygen saturation in the OHS group (P < .05). CONCLUSIONS: PAP therapy can significantly improve CPC stability in patients with obesity with OSA or OHS, with key differences. Elevated low-frequency coupling narrow band may function as a surrogate biomarker for early subclinical cardiac disease. Low awake oxygen saturation could also increase this biomarker in OHS. CLINICAL TRIAL REGISTRATION: Registry: Australian New Zealand Clinical Trials Registry; Name: Obesity Hypoventilation Syndrome and Neurocognitive Dysfunction; URL: https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=367492; Identifier: ACTRN12615000122550. CITATION: Sivam S, Wang D, Wong KKH, et al. Cardiopulmonary coupling and serum cardiac biomarkers in obesity hypoventilation syndrome and obstructive sleep apnea with morbid obesity. J Clin Sleep Med. 2022;18(4):1063-1071.