BACKGROUND AND OBJECTIVE:Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a well-established treatment for various haematologic and oncologic disorders, yet its clinical success is frequently compromised by complications such as pulmonary graft-versus-host disease (GvHD). Spirometry is the gold standard for monitoring and diagnosis, but it is insensitive to small airway changes. Oscillometry may complement spirometry as a way of detecting change in small airway function. This study assessed the longitudinal change and variability in spirometry and oscillometry following allo-HSCT and predictors of this change. METHODS:Longitudinal spirometry and oscillometry were retrospectively obtained from all patients (n = 374) who underwent allo-HSCT at Royal North Shore Hospital in Sydney, Australia, between January 2015 and December 2023. RESULTS:Baseline post allo-HSCT assessments showed significantly lower FEV1 and FVC in the allo-HSCT group compared to controls. Over the follow-up period, oscillometric indices displayed significant worsening of Rrs5 and Xrs5, whereas FEV1 did not significantly change. Severe cGvHD was associated with a modest decline in FEV1/FVC and Xrs5 trajectory. Notably, a subset of patients demonstrated discordant changes between spirometry and oscillometry, suggesting that oscillometry may capture early small airway dysfunction not evident on traditional spirometric measures. CONCLUSION:These findings underscore the potential of oscillometry as a complementary tool in the routine monitoring of lung function post-allo-HSCT. By detecting subtle changes in small airway mechanics, oscillometry could facilitate earlier identification and intervention in patients at risk for developing pulmonary cGvHD, thereby improving long-term clinical outcomes.

INTRODUCTION:Subjective sleep disturbance is common in chronic obstructive pulmonary disease (COPD) and is related to hyperinflation when supine and tidal expiratory flow limitation (EFL). We hypothesised that abnormalities in supine lung mechanics disturb sleep and impair gas exchange in COPD. We aimed to assess relationships between supine lung derecruitment, EFL and hyperinflation, and polysomnographic measures of sleep disturbance and gas exchange in COPD. METHODS:In this prospective, observational study, supine oscillometry was performed in stable COPD patients to assess lung derecruitment (reactance at 5 Hz (Xrs5) z-score) and EFL (difference between mean inspiratory and expiratory reactance (∆Xrs5)). Hyperinflation was assessed by supine inspiratory capacity (ICsupine) z-score. In-laboratory polysomnography was used to assess sleep disturbance, measured by Apnoea-Hypopnoea Index (AHI), Oxygen Desaturation Index (ODI) and AHI during rapid eye movement sleep (AHI REM). Monitoring of transcutaneous carbon dioxide (TcCO2), and measurements of partial pressure of arterial carbon dioxide (PaCO2) and HCO3 - were performed in a subgroup. RESULTS:28 COPD patients were enrolled (13 female, mean age (SD) 67.5 (8.71) years and mean forced expiratory volume in 1second (FEV1) z-scores (SD) -2.61 (1.06)). Worse Xrs5(supine) correlated with greater respiratory arousals (AHI rs =0.47, p=0.01; ODI rs=-0.58, p=0.001), as did greater ∆Xrs5(supine) (AHI REM rs=0.53, p=0.005). Xrs5(supine) correlated with peripheral oxygen saturation nadir (rs=0.43, p=0.02). ICsupine correlated negatively with hypoventilation (PaCO2 rs=-0.77, p=0.001; HCO3 - rs=-0.78, p=0.001, n=15), as did Xrs5(supine) (rise in TcCO2 rs=-0.65, p=0.009). CONCLUSION:Lung derecruitment, EFL and supine hyperinflation likely contribute to sleep disturbance and sleep-related gas exchange impairment in COPD.

Rationale: The incremental shuttle walk test (ISWT) correlates closely with peak oxygen uptake in COPD and relates to important outcomes such as mortality, response to treatment and hospital readmission. Despite this, there is limited data on the physiological determinants of ISWT distance (ISWD) in COPD. Methods: In this exploratory, prospective observational study, spirometry, lung volumes, diffusion capacity (DLCO) and oscillometry were performed in patients with confirmed COPD. Patients then completed two ISWT with the results of the best test, measured by distanced walked taken. The determinants of ISWD and dyspnoea measured by BORG score were evaluated. Results: 25 COPD patients, mean (SD) age 71 (8.82) years, 48% female with a mean (SD) FEV1 Z-score -2.54 (0.83) were recruited. Median (IQR) ISWD was 350 (210-440) metres (mean (SD) 66.4 (27.9)% predicted distance). Most patients (85%) stopped due to inability to maintain walking speed with submaximal mean heart rate of 77.3 (10.1)% predicted and BORG dyspnoea score of 'severe' (median 5/10 (IQR 4-5.5)). Inspiratory capacity to TLC ratio (IC/TLC) correlated strongly with ISWD, even when corrected for age and height (rs = 0.59 p = 0.02). Oscillatory reactance (Xrs5) and DLCO were also correlated with ISWD. There were no oscillometric or spirometric predictors of dyspnoea. Conclusion: Resting hyperinflation measured by IC/TLC, predicted ISWD despite submaximal dyspnoea, suggesting that hyperinflation may not be the mechanism that limits exercise performance, but rather reflects overall impairment in COPD.

Introduction COPD is characterised by airflow obstruction, expiratory airway collapse and closure causing expiratory flow limitation (EFL) and hyperinflation. Supine posture may worsen ventilatory function in COPD, which may cause hyperinflation to persist and contribute to symptoms of orthopnoea and sleep disturbance. Our aim was to determine the impact of supine posture on hyperinflation, dynamic elastance and EFL in COPD and healthy subjects. We hypothesised that changes in hyperinflation in supine posture are influenced by EFL and gas trapping in COPD. Methods Clinically stable COPD patients (compatible symptoms, smoking >10 pack-years, obstructed spirometry) and healthy controls underwent oscillometry in the seated and supine positions. Hyperinflation was measured by inspiratory capacity (IC) and the ratio of IC to total lung capacity (IC/TLC) while seated and supine EFL was measured as the difference in mean inspiratory and mean expiratory oscillatory reactance at 5 Hz (Xrs5). Relationships between IC, IC/TLC and Xrs5, were examined by Spearman correlation. Results 42 COPD patients demonstrated no change in IC/TLC from seated (0.31 L) to supine (0.32 L) position (p=0.079) compared to significant increases seen in 14 control subjects (0.37 L seated versus 0.44 L supine; p<0.001). In COPD, worse dynamic elastance (Xrs5 rs 0.499; p=0.001) and EFL (ΔXrs5 rs −0.413; p=0.007), along with increased age and lower body-mass-index were predictors of supine hyperinflation. Conclusion Supine persistent hyperinflation occurs in COPD and is associated with increased dynamic elastance and EFL, likely the result of increased airway closure due to gravitational redistribution of lung mass.

BACKGROUND:Many individuals with chronic obstructive pulmonary disease (COPD) experience frequent hospitalization and readmissions, which is burdensome on the health system. This study aims to investigate factors associated with unplanned readmissions and mortality following a COPD-related hospitalization over a 12-month period in Australia, focusing on mental disorders and accounting for the acute phase of the COVID-19 pandemic. METHODS:A retrospective cohort study using linked hospitalization and mortality records identified individuals aged ≥40 years who had at least one hospital admission with a principal diagnosis of COPD between 2014 and 2020 in New South Wales, Australia. A semi-competing risk analysis was conducted to examine factors associated with unplanned readmission and mortality. RESULTS:Adults with a mental disorder diagnosis, specifically anxiety, had a higher risk of 12-month unplanned readmission. Individuals with anxiety and dementia also had a higher risk of mortality pre- and post-unplanned readmission. Individuals who were admitted during the acute phase of the COVID-19 pandemic period had lower risk of unplanned readmission, but higher risk of mortality without unplanned readmission. CONCLUSION:Interventions aimed at reducing admissions should consider adults living with mental disorders such as anxiety or dementia to improve healthcare delivery and health outcomes for individuals living with COPD.

A 64-year-old obese gentleman attended for further evaluation of ongoing dyspnoea in the context of a previous diagnosis of moderate COPD treated with dual long-acting bronchodilators. A cardiopulmonary exercise test (CPET) was performed, which demonstrated reduced peak work and oxygen consumption with evidence of dynamic hyperinflation, abnormal gas exchange and ventilatory limitation despite cardiac reserve. The CPET clarified the physiological process underpinning the patient's dyspnoea and limiting the patient's activities. This, in turn, helped the clinician tailor the patient's management plan.

Introduction: Chronic Obstructive Pulmonary Disease (COPD) is responsive to bronchodilator (BD). However, it is unclear how BD alters ventilation distribution. Aims: To determine the effect of BD on the extent and distribution of ventilation in COPD measured by Single Photon Emission Computed Tomography (SPECT)/Computed Tomography (CT). Methods: 10 participants (6M) with physician diagnosed COPD underwent baseline spirometry and a SPECT/CT pre and post BD. A significant BD response was an increase of 200mL and 12% in FEV1 or FVC. Both lungs were segmented into outer, middle, and inner shells, from the CT which were 40%, 30%, and 30% of each lungs' volume respectively. From fused SPECT/CT, we calculated ventilation as; 1) percentage of total CT lung volume (VentTotal), 2) percentage in each shell (VentShell) and 3) each shell's ventilation as a proportion of total ventilation (ShellTotal). Results: 3/10 participants had significant BD responses. VentTotal did not change following BD (p=0.13). VentShell decreased in the inner shell exclusively (p=0.004). ShellTotal significantly increased in the outer shells (ShellTotal Δ=1.19, p=0.003) and decreased in the inner shells (ShellTotal Δ =-1.31, p=0.001). ShellTotal did not undergo significant change in the middle shells (ShellTotal Δ = 0.06, p=0.8). % change in ShellTotal in the middle shells correlated significantly with % change in FEV1 (p=0.003, r=-0.86) and FVC (p=0.02, r=-0.74). Conclusion: SPECT imaging is sensitive to changes in the pattern of ventilation following BD in COPD, showing that ventilation is redistributed from the central to the peripheral areas of the lungs.

We recently developed a model-based method for analyzing multiple breath nitrogen washout data that does not require identification of Phase-III. In the present study, we assessed the effect of irregular breathing patterns on the intra-subject variabilities of the model parameters. Nitrogen fraction at the mouth was measured in 18 healthy and 20 asthmatic subjects during triplicate performances of multiple breath nitrogen washout, during controlled (target tidal volume 1 L at 8–12 breaths per minute) and free (unrestricted) breathing. The parameters Scond, Sacin and functional residual capacity (FRC) were obtained by conventional analysis of the slope of Phase-III. Fitting the model to the washout data provided functional residual capacity (FRCM), dead space volume (VD), the coefficient of variation of regional specific ventilation ( C_V,V̇_e ), and the model equivalent of Sacin (Sacin-M). Intra-participant coefficients of variation for the model parameters for both health and asthma were FRCM < 5.2 C_V,V̇_e < 9.0 C_V,V̇_e < 13.2 C_V,V̇_e that is less affected by irregularities in the breathing pattern than its corresponding Phase-III slope analysis parameter Scond.

The Thoracic Society of Australia and New Zealand (TSANZ) and the Australian and New Zealand Society of Respiratory Science (ANZSRS) commissioned a joint position paper on pulmonary function testing during coronavirus disease 2019 (COVID-19) in July 2021. A working group was formed via an expression of interest to members of both organizations and commenced work in September 2021. A rapid review of the literature was undertaken, with a 'best evidence synthesis' approach taken to answer the research questions formed. This allowed the working group to accept findings of prior relevant reviews or societal document where appropriate. The advice provided is for providers of pulmonary function tests across all settings. The advice is intended to supplement local infection prevention and state, territory or national directives. The working group's key messages reflect a precautionary approach to protect the safety of both healthcare workers (HCWs) and patients in a rapidly changing environment. The decision on strategies employed may vary depending on local transmission and practice environment. The advice is likely to require review as evidence grows and the COVID-19 pandemic evolves. While this position statement was contextualized specifically to the COVID-19 pandemic, the working group strongly advocates that any changes to clinical/laboratory practice, made in the interest of optimizing the safety and well-being of HCWs and patients involved in pulmonary function testing, are carefully considered in light of their potential for ongoing use to reduce transmission of other droplet and/or aerosol borne diseases.

This study examines if and how drivers respond to tolls differently after implementation by analyzing drivers’ intention to pay tolls and toll avoidance behaviors. We apply the Theory of Planned Behavior to connect intention to pay and avoidance behavior to three categories of predictors: attitudes toward tolls, perceptions of toll benefits, and ability to pay. Since the theory does not explicitly consider factors such as past experience and changes in the decision-making process over time, we utilize three analytical approaches to examine: (1) if time affects intention to pay tolls and toll avoidance behavior; (2) pathways through which time makes a difference, and (3) how factors influencing intention behaviors change pre- and post-toll implementation. We find that time does in fact matter; there are direct and indirect pathways through which time makes a difference and time changes the strength of the relationships between intention to pay and behavior.

There is growing reliance on road tolls for revenue and for highway congestion management. However, there is limited research, in the U.S. context, on how drivers change their behavior in response to tolls. But experiences in Europe and Asia find that drivers respond to tolls through a variety of behavioral shifts. Such behaviors have implications for the revenue generating capabilities of tolls as well as the effectiveness of tolls as a traffic management tool. This research applies the Theory of Planned Behavior to examine drivers' behavioral responses to tolls. We connect a preference for tolls as a funding source, ability to pay, and perceptions of toll benefits to the support for tolls, and, subsequently, to a number of toll avoidance responses. We examine the following toll avoidance behavior: changing home or employment location; changing commute; avoiding travel to destinations that require tolls; and telecommuting or working from home. Using data from a 2014 survey of drivers in the Hampton Roads region of Virginia, conducted nine months after toll implementation, we find that a higher willingness to pay decreases the likelihood of toll avoidance behavior and that the preference for tolls over taxes and the timing of travel impact willingness to pay, as well as race of the driver. Age, gender, education, and race influence toll avoidance behavior. Our findings suggest social justice be considered when developing a toll system, especially the impact on short-term and long-term toll avoidance behaviors.

Introduction:The multiple breath nitrogen washout (MBNW) test provides important clinical information in obstructive airways diseases. Recently, a significant cross-sensitivity error in the O2 and CO2 sensors of a widely used commercial MBNW device (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) was detected, which leads to overestimation of N2 concentrations. Significant errors in functional residual capacity (FRC) and lung clearance index (LCI) have been reported in infants and children. This study investigated the impact in adults, and on additional important indices reflecting conductive (S cond) and acinar (S acin) ventilation heterogeneity, in health and disease. Methods:Existing MBNW measurements of 27 healthy volunteers, 20 participants with asthma and 16 smokers were reanalysed using SPIROWARE V 3.3.1, which incorporates an error correction algorithm. Uncorrected and corrected indices were compared using paired t-tests and Bland-Altman plots. Results:Correction of the sensor error significantly lowered FRC (mean difference 9%) and LCI (8-10%) across all three groups. S cond was higher following correction (11%, 14% and 36% in health, asthma and smokers, respectively) with significant proportional bias. S acin was significantly lower following correction in the asthma and smoker groups, but the effect was small (2-5%) and with no proportional bias. Discussion:The O2 and CO2 cross-sensitivity sensor error significantly overestimated FRC and LCI in adults, consistent with data in infants and children. There was a high degree of underestimation of S cond but minimal impact on S acin. The presence of significant proportional bias indicates that previous studies will require reanalysis to confirm previous findings and to allow comparability with future studies.

Heterogeneity is an intrinsic property of the lungs. Structurally, it is evident in the complex branching of the airways and the spatial distribution of tissue throughout the lung. Functionally, this translates to variation in the distribution of airway resistance and lung compliance, resulting in disparity in the filling and emptying rates between individual compartments, and consequently heterogeneous distribution of ventilation. Disease causes pathological alterations to structure and function, causing corresponding changes to heterogeneity, which can be measured via functional imaging, oscillometry or gas washout methods. This review describes key relevant concepts, and presents the most recent evidence for the significance of heterogeneity as a marker of disease severity and potential predictor of treatment or intervention response.

Respiratory oscillometry (or forced oscillation technique (FOT)), measures the mechanical properties of the respiratory system by superimposing oscillatory pressure waves at the mouth during quiet tidal breathing. Parameters include respiratory system resistance (Rrs), a measure of airway calibre, and reactance (Xrs), representing the elastic and inertive properties which are sensitive to airway closure [1]. FOT is increasingly being used for clinical monitoring of airways disease, which complements spirometric function [2]. FOT parameters have good long-term repeatability in patients with stable obstructive airways disease, facilitating its ability to detect sensitive changes in airways disease. Novel cut-off values presented may help determine clinically significant change. https://bit.ly/3emL7FI

Medical Journal of AustraliaVolume 217, Issue 10 p. 548-548 Letters What doctors should consider before prescribing e-liquids for e-cigarettes Alexander Larcombe, Alexander Larcombe Telethon Kids Institute, Perth, WA Curtin University, Perth, WASearch for more papers by this authorDavid Chapman, David Chapman University of Technology, Sydney, Sydney, NSWSearch for more papers by this authorMiranda Ween, Corresponding Author Miranda Ween miranda.ween@adelaide.edu.au orcid.org/0000-0002-0600-4585 University of Adelaide, Adelaide, SACorresponding author: miranda.ween@adelaide.edu.auSearch for more papers by this author Alexander Larcombe, Alexander Larcombe Telethon Kids Institute, Perth, WA Curtin University, Perth, WASearch for more papers by this authorDavid Chapman, David Chapman University of Technology, Sydney, Sydney, NSWSearch for more papers by this authorMiranda Ween, Corresponding Author Miranda Ween miranda.ween@adelaide.edu.au orcid.org/0000-0002-0600-4585 University of Adelaide, Adelaide, SACorresponding author: miranda.ween@adelaide.edu.auSearch for more papers by this author First published: 23 October 2022 https://doi.org/10.5694/mja2.51765Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume217, Issue10November 2022Pages 548-548 RelatedInformation

Airway smooth muscle cells from severe asthma patients with FAO respond to β2-agonists and corticosteroids in vitro, and at a level similar to mild asthmatics. Intrinsic dysfunction of these signalling pathways is unlikely to contribute to FAO. https://bit.ly/3muvNsW.