Combination pharmacological therapy targeting multiple mechanisms of sleep apnoea: a randomised controlled cross-over trial.

Rationale: Acetazolamide and atomoxetine-plus-oxybutynin ('AtoOxy') can improve obstructive sleep apnoea (OSA) by stabilising ventilatory control and improving dilator muscle responsiveness respectively. Given the different pathophysiological mechanisms targeted by each intervention, we tested whether AtoOxy-plus-acetazolamide would be more efficacious than AtoOxy alone.

Methods: In a multicentre randomised crossover trial, 19 patients with moderate-to-severe OSA received AtoOxy (80/5 mg), acetazolamide (500 mg), combined AtoOxy-plus-acetazolamide or placebo at bedtime for three nights (half doses on first night) with a 4-day washout between conditions.

A review of supine position related obstructive sleep apnea: Classification, epidemiology, pathogenesis and treatment.

Supine related obstructive sleep apnea (OSA) is the most common clinical and physiological phenotype of OSA. This condition is recognizable by patients, their families and through polysomnographic recordings. Commonly used definitions distinguish the presence of supine related OSA when respiratory events occur at twice the frequency when the patient lies in the supine compared to non-supine sleeping positions.

Mechanisms relating to sleeping position to the endotypes of sleep disordered breathing.

Purpose: Obstructive sleep apnea (OSA) severity varies considerably depending on the body position during sleep in certain subjects. Such variability may be underpinned by specific, body position-related changes in OSA pathophysiological determinants, or endotypes. Also head position relative to trunk may influence OSA endotypes.

Oronasal vs Nasal Masks: The Impact of Mask Type on CPAP Requirement, Pharyngeal Critical Closing Pressure (P), and Upper Airway Cross-Sectional Areas in Patients With OSA.

Background: CPAP delivered via an oronasal mask is associated with lower adherence, higher residual apnea-hypopnea index (AHI), and increased CPAP therapeutic pressure compared with nasal masks. However, the mechanisms underlying the increased pressure requirements are not well understood.

Research Question: How do oronasal masks affect upper airway anatomy and collapsibility?

Study Design And Methods: Fourteen patients with OSA underwent a sleep study with both a nasal and oronasal mask, each for one-half of the night (order randomized).

A single dose of noradrenergic/serotonergic reuptake inhibitors combined with an antimuscarinic does not improve obstructive sleep apnoea severity.

Previous trials have demonstrated that the combination of noradrenergic reuptake inhibitors with an antimuscarinic can substantially reduce the apnoea-hypopnoea index (AHI) and improve airway collapsibility in patients with obstructive sleep apnoea (OSA). However, some studies have shown that when administered individually, neither noradrenergic or serotonergic agents have been effective at alleviating OSA. This raises the possibility that serotonergic agents (like noradrenergic agents) may also need to be delivered in combination to be efficacious.

Examining the impact of multilevel upper airway surgery on the obstructive sleep apnoea endotypes and their utility in predicting surgical outcomes.

Background And Objective: Upper airway surgery for obstructive sleep apnoea (OSA) is an alternative treatment for patients who are intolerant of continuous positive airway pressure (CPAP). However, upper airway surgery has variable treatment efficacy with no reliable predictors of response. While we now know that there are several endotypes contributing to OSA (i.

Fit-Tested N95 Masks Combined With Portable High-Efficiency Particulate Air Filtration Can Protect Against High Aerosolized Viral Loads Over Prolonged Periods at Close Range.

Background: Healthcare workers (HCWs) are at risk from aerosol transmission of severe acute respiratory syndrome coronavirus 2. The aims of this study were to (1) quantify the protection provided by masks (surgical, fit-testFAILED N95, fit-testPASSED N95) and personal protective equipment (PPE), and (2) determine if a portable high-efficiency particulate air (HEPA) filter can enhance the benefit of PPE.

Methods: Virus aerosol exposure experiments using bacteriophage PhiX174 were performed.

Body position during laboratory and home polysomnography compared to habitual sleeping position at home.

Study Objectives: Supine-predominant obstructive sleep apnea (OSA) is highly prevalent. The proportion of time spent in the supine position may be overrepresented during polysomnography, which would impact on the apnea-hypopnea index (AHI) and have important clinical implications. We aimed to investigate the difference in body position during laboratory or home polysomnography compared to habitual sleep and estimate its effect on OSA severity.

Clinical polysomnographic methods for estimating pharyngeal collapsibility in obstructive sleep apnea.

Study Objectives: Obstructive sleep apnea has major health consequences but is challenging to treat. For many therapies, efficacy is determined by the severity of underlying pharyngeal collapsibility, yet there is no accepted clinical means to measure it. Here, we provide insight into which polysomnographic surrogate measures of collapsibility are valid, applicable across the population, and predictive of therapeutic outcomes.

Point of emission air filtration enhances protection of healthcare workers against skin contamination with virus aerosol.

Editorial

Breath-holding as a novel approach to risk stratification in COVID-19.

Background: Despite considerable progress, it remains unclear why some patients admitted for COVID-19 develop adverse outcomes while others recover spontaneously. Clues may lie with the predisposition to hypoxemia or unexpected absence of dyspnea ('silent hypoxemia') in some patients who later develop respiratory failure. Using a recently-validated breath-holding technique, we sought to test the hypothesis that gas exchange and ventilatory control deficits observed at admission are associated with subsequent adverse COVID-19 outcomes (composite primary outcome: non-invasive ventilatory support, intensive care admission, or death).

Acute oxygen use in hospitalised patients with chronic obstructive pulmonary disease is guideline discordant.

Ample evidence supports an association between acute oxygen over-administration and harm. Australian and international guidelines consistently recommend lower oxygen saturation aims in populations with chronic obstructive pulmonary disease (COPD). We assessed adherence to acute oxygen use guidelines and outcomes in hospitalised patients with COPD at a large Australian metropolitan hospital network.

Interstitial lung disease and obstructive sleep apnea.

Obstructive sleep apnea (OSA) is one of the most common comorbidities in patients with interstitial lung disease (ILD). Growing evidence highlights the significance of sleep disturbance on health outcomes in this population. The relationships between ILD and OSA are complex and possibly bidirectional, with multiple mechanisms postulated for the pathogenic and physiologic links.

Considering the Role of Adherence in New and Emerging Sleep Treatments.

There are several novel and emerging treatments for obstructive sleep apnea (OSA), including new devices and pharmacotherapies. Long-term efficacy and adherence data for these interventions in the sleep context are lacking. Future studies exploring the long-term adherence and efficacy in novel and emerging treatments of OSA are required to fully understand the place of these treatments in treatment hierarchies.

Viable virus aerosol propagation by positive airway pressure circuit leak and mitigation with a ventilated patient hood.

Introduction: Nosocomial transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a major feature of the COVID-19 pandemic. Evidence suggests patients can auto-emit aerosols containing viable viruses; these aerosols could be further propagated when patients undergo certain treatments, including continuous positive airway pressure (PAP) therapy. Our aim was to assess 1) the degree of viable virus propagated from PAP circuit mask leak and 2) the efficacy of a ventilated plastic canopy to mitigate virus propagation.

Assessing the Physiologic Endotypes Responsible for REM- and NREM-Based OSA.

Background: Patients with OSA can have the majority of their respiratory events in rapid eye movement (REM) sleep or in non-rapid eye movement (NREM) sleep. No previous studies have linked the different physiologic conditions in REM and NREM sleep to the common polysomnographic patterns seen in everyday clinical practice, namely REM predominant OSA (REM) and NREM predominant OSA (NREM).

Research Question: (1) How does OSA physiologic condition change with sleep stage in patients with NREM and REM? (2) Do patients with NREM and REM have different underlying OSA pathophysiologic conditions?

Study Design And Methods: We recruited patients with three polysomnographic patterns.

Surgical management of obstructive sleep apnoea: A position statement of the Australasian Sleep Association.

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

A randomized controlled trial of oxygen therapy for patients who do not respond to upper airway surgery for obstructive sleep apnea.

Study Objectives: We aimed to determine whether patients diagnosed with obstructive sleep apnea (OSA) who fail to respond to upper airway surgery may be successfully treated with supplemental oxygen and whether we could identify baseline physiologic endotypes (ie, collapsibility, loop gain, arousal threshold, and muscle compensation) that predict response to oxygen therapy.

Methods: We conducted a single night, randomized double-blinded cross over trial in which patients with OSA who failed to respond to upper airway surgery were treated on separate nights with oxygen therapy (4 L/min) or placebo (medical air). Effect of oxygen/air on OSA on key polysomnography outcomes were assessed: apnea-hypopnea index (AHI), AHI without desaturation (ie, flow-based AHI), arousal index, and morning blood pressure.