BACKGROUND:Surgical and N95 masks are commonly used in the prevention of respiratory virus transmission. The safety of wearing masks is well documented in healthy individuals but is unclear in people with chronic hypercapnia. In addition, masks are often poorly tolerated in this population. The present study assessed the effect of surgical and N95 masks in people with stable chronic hypercapnia using noninvasive ventilation (NIV). METHODS:A randomized crossover trial was performed. SpO2 and transcutaneous CO2 (PtcCO2) were measured in participants wearing a surgical mask, an N95 mask, and no mask for a 20-min period at rest. Secondary outcomes included heart rate, breathing frequency, the A1 scale from the Multidimensional Dyspnea Profile (MDP), and the modified Borg dyspnea scale (mBORG). RESULTS:24 participants (50% female; mean [SD] age 61 [13] years) were randomized and completed data collection. Over the 20-min study period, when compared with no mask, the mean differences for SpO2 in surgical and N95 masks were 0.0% [95% CI: -1.0-0.9] and 0.3% [95% CI: -0.6-1.3]. For PtcCO2 surgical mask, the mean difference was 0.0 mm Hg [95% CI: -1.3-1.3], and for N95 mask, the mean difference was 1.0 mm Hg [95% CI: 0.3-2.3]. There was no effect on heart rate or breathing frequency. Masks increased the mBORG (surgical mask median difference 0.75 points [95% CI: 0.25-2.00]; N95 mask median difference 1.50 [95% CI: 0.75-2.25]) and MDP (surgical mask median difference 1.5 points [95% CI: 0.5-2.5]; N95 mask median difference 2.5 points [95% CI: 1.0-3.0]) compared with no mask. Three participants requested to remove one or both masks early. CONCLUSIONS:Wearing a surgical mask and N95 mask did not significantly affect gas exchange in subjects with chronic hypercapnia using NIV. However, dyspnea and breathing discomfort did increase.

Abstract Background Non-invasive ventilation (NIV) uses positive pressure to assist people with respiratory muscle weakness or severe respiratory compromise to breathe. Most people use this treatment during sleep when breathing is most susceptible to instability. The benefits of using NIV in motor neurone disease (MND) are well-established. However, uptake and usage are low (~ 19%) and there is no consensus on how to best implement NIV in MND in Australia. Consequently, clinical practice models are highly variable. Our team has recently provided evidence that specific and individualised NIV titration using a sleep study (polysomnography; PSG) leads to better outcomes in people with MND. However, for this clinical practice model to result in sustained benefits, evidence of effectiveness across multiple sites, as well as culture and practice change, must occur. Methods A two-arm, assessor-blinded, individual participant randomised controlled trial in MND care centres across Australia will be undertaken. Two-hundred and forty-four participants will be randomised (1:1) to either the intervention group (PSG-assisted commencement of NIV settings; PSG) or a control group (sham PSG). Participants will be asked to use their NIV device for 7 weeks and will then return for follow-up assessments. Respiratory, sleep and patient-reported outcome measures will be collected at baseline and follow-up. The primary aim is to determine if the proportion of participants using NIV for > 4 h/day during the intervention period is higher in the PSG than the control group. A process evaluation, health economic evaluation and 12-month cohort follow-up will be undertaken and reported separately. Discussion The results of this trial will demonstrate the effects of PSG-assisted titration of NIV on usage of NIV in people with MND. We hypothesise that the PSG intervention will improve synchrony between the user and the machine, which will lead to greater NIV usage compared to the control group. Trial registration ClinicalTrials.gov NCT05136222. Registered on November 25, 2021.

BACKGROUND:Pulse oximetry-derived measures of autonomic vascular re-activity during sleep, quantified by pulse wave amplitude drop (PWAD) characteristics such as the PWAD index, have recently been proposed as a biomarker of cardiovascular disease (CVD) outcomes in patients with OSA. RESEARCH QUESTION:Are PWAD characteristics associated with Framingham 10-year CVD risk score in a sleep clinic population? STUDY DESIGN AND METHODS:This study examined PWAD characteristics in 725 individuals (38% female; median [interquartile range] age, 52 [39-63] years; BMI, 28.6 [24.9-33.2] kg/m2) who underwent diagnostic polysomnography and had sufficient clinical data to determine CVD status and calculate a Framingham 10-year CVD risk score. Individuals were categorized as either having established CVD (CVDESTABLISHED, n = 110) or a Framingham 10-year CVD risk score that was elevated (CVDELEVATED, n = 407) or low (CVDLOW, n = 208). Standard polysomnography variables and PWAD characteristics, including PWADINDEX (number of PWAD events that occurred during all sleep stages divided by total sleep time [events/h]) and PWADDURATION (average duration of PWAD events [seconds]), were compared between groups. RESULTS:The PWADINDEX was lower (P < .01) in the CVDESTABLISHED (28.5 [13.2-45.2] events/h) and CVDELEVATED (38.7 [20.8-53.0] events/h) groups than in the CVDLOW group (47.7 [35.7-62.6] events/h). The PWADDURATION was longer (P < .01) in CVDESTABLISHED (10.4 [8.2-14.5] seconds) and CVDELEVATED (8.7 [7.6-10.1] seconds) groups than in CVDLOW group (8.0 [7.2-8.8] seconds). Similar group differences were observed during rapid-eye movement and non-rapid-eye movement sleep, and in patients with and without OSA. The magnitude difference in PWADINDEX and PWADDURATION remained similar after adjusting for age, sex, BMI, BP, total sleep time, apnea-hypopnea index, and oxygen desaturation index (adjusted PWADINDEX [95% CI] was 34.2 [29.9-38.7] in CVDESTABLISHED, 39.4 [37.1-41.6] in CVDELEVATED, and 46.6 [42.5-50.7] in CVDLOW; P < .01). INTERPRETATION:These data indicate that PWAD characteristics may provide a complementary marker of CVD risk in sleep clinic populations with and without OSA. The pathophysiologic mechanisms linking nocturnal PWAD characteristics and CVD risk require further study.

OBJECTIVES:This is a protocol for a Cochrane Review (intervention). The objectives are as follows: The objective of this review is to evaluate the efficacy of non-invasive mechanical ventilation (NIV) in chronic hypoventilation due to myotonic dystrophy (MD). The aims of this review are to synthesize and assess the available literature to support evidence-based clinical practice and to provide recommendations for future evaluation and research.

BACKGROUND AND OBJECTIVE:Nocturnal pulse oximetry (NPO) is a simple and inexpensive assessment tool that has previously been shown to correlate with prognosis and timing of non-invasive ventilation (NIV) initiation in people living with motor neuron disease (plwMND). However, the optimal number of nights for measuring NPO has not been defined for this population, with other respiratory conditions exhibiting both low and high night-to-night variability in NPO parameters. This study aims to determine the inter-night variability in NPO data over three nights in plwMND. METHODS:We conducted a retrospective analysis of 132 studies in which plwMND underwent three consecutive nights of NPO. Intraclass correlation coefficients (ICC) were used to assess the reliability of key NPO parameters, including mean percentage of total recording time with oxygen saturation (SpO2) < 90% (T90), oxygen desaturation index (ODI), basal SpO2 and nadir SpO2. The proportion of plwMND meeting NIV criteria based on single-night versus multi-night assessments was also compared. RESULTS:Excellent reliability was observed for T90 (ICC(1) = 0.940) and ODI (ICC(1) = 0.901), while basal SpO2 (ICC(1) = 0.845) and nadir SpO2 (ICC(1) = 0.768) demonstrated good reliability. However, relying on a single-night NPO assessment failed to identify 12% of plwMND who met NIV criteria when evaluated over three nights. CONCLUSION:Despite good to excellent inter-night variability of NPO data in plwMND, multi-night NPO monitoring improves the accuracy of identifying plwMND requiring NIV. These findings support the need for multi-night assessments to enhance clinical decision-making in MND management.

The role of non-invasive ventilation (NIV) in patients with cystic fibrosis (pwCF) includes use in both the management of hypercapnic respiratory failure and as an adjunct to airway clearance techniques. We performed a retrospective review of the Australian Cystic Fibrosis Data Registry to analyse the characteristics of pwCF requiring NIV. We demonstrated that despite improvements in overall health in pwCF there is still a significant role of NIV in this population.

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. 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. Clinical characteristics between the two test groups differed significantly, 45

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.

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.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.

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.

Currently, evidence-based guidelines about cleaning positive airway pressure devices for maintenance or reprocessing for a new user do not exist. There is no strong evidence of harm caused by contaminated positive airway pressure equipment. Future research opportunities exist to streamline cleaning processes, assure hygiene, and reduce waste.

Background: Humidification circuit type and performance of a circuit calibration may affect pressure and tidal volume (VT) delivery during NIV. Aims: To determine the effect of three different humidification circuits on pressure and VT delivery in the setting of normal lungs, increased airway resistance (RAW) and reduced lung compliance (CL). Method: Using a life-support ventilator (Philips Trilogy Evo©), three circuits (standard tubing (ResMed), RT-202 (Fisher & Paykel), 950A61 (Fisher & Paykel)) were connected to a test lung and delivered inspiratory positive airway pressure (IPAP) and VT were measured. Each circuit was tested under 9 randomly ordered experimental conditions that combined: respiratory mechanics (normal, increased RAW, decreased CL) and IPAP (10, 15, 20cmH2O). Expiratory posiitve airway pressure was set at 5cmH2O. The effect of circuit calibration was also tested for RT-202 and 950A61 circuits. Results: Pooled data from all IPAP and lung conditions showed a calibrated RT202 circuit reduced delivered IPAP (-0.3cmH2O [95%CI -0.29 to -0.31]) and VT (-39ml [-38, -40]) compared with a standard circuit. In contrast, small increases in delivered IPAP (0.2cmH2O [0.19, 0.21] and VT (7ml [6.1, 7.6] were seen with the 950A61 circuit compared to standard tubing. Delivered IPAP was closer to set IPAP for the 950A61 circuit. The greatest drop in VT was 87mL (-89 to -86) with the RT202 and increase in IPAP was 0.91cmH2O (0.88 to 0.93) with the 950A61 at set IPAP 20cmH2O. Circuit calibration increased VT and measured IPAP for both RT202 and 950A61 circuits. Conclusion: Changing humidifier circuit type can significantly impact pressure and VT delivery.