ARTP statement on pulmonary function testing 2020

The utility of dynamic chest radiography in patients with asthma, COPD, COVID-19 and ILD: A pilot study

INTRODUCTION AND OBJECTIVES

Assessment of breathlessness requires a combination of imaging and lung function testing. Dynamic digital radiography (DDR) of the thorax is an imaging technique that allows physiological and anatomical information to be gathered at the time of chest X-ray and has the potential to significantly streamline diagnostic pathways. The aims of this study were to investigate the acceptability of DDR to patients and explore the correlation between DDR-derived measurements with lung volumes measured using full pulmonary function tests (PFT).

MATERIALS AND METHODS

We conducted a single-centre, prospective, pilot study of patients with confirmed asthma, chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD) or post-COVID-19 infection. Participants underwent DDR and paired PFT between March 2021 and August 2022. Dynamic digital radiography acceptability was measured using a 10-cm visual analogue scale (VAS). Point estimates and exact confidence intervals were used to evaluate participant preference. Digital dynamic radiography would be considered acceptable if the lower bound of the 95% confidence interval (exact) is greater than 50%. Pearson correlation (r) was used to explore associations between DDR measurements and PFT parameters.

RESULTS

40 participants (asthma, n = 11; COPD, n = 9; ILD, n = 11; post-COVID, n = 9) had DDR with adequate image acquisition and PFT. Mean age of participants was 63.38 years (standard deviation 14.89) and 63% were male (25/40). The lower 95% confidence interval threshold for VAS acceptability was 92% for all groups combined and considered acceptable. The projected lung area at end inspiration (PLAinsp) closely correlated with total lung capacity across all disease cohorts (r = 0.80, p < 0.001) and projected lung area at end expiration (PLAexp) was strongly correlated with residual volume in airways disease (COPD: r = 0.87, p = 0.003; asthma: r = 0.85, p = 0.002).

CONCLUSION

Dynamic digital radiography is an acceptable investigation for respiratory patients. DDR-derived measurements correlate with lung volumes obtained from PFTs. Larger studies are required to validate DDR as a possible method to identify and monitor air trapping in airways disease, allowing early detection and assessment of treatment effectiveness.

Reference values for arm ergometry cardiopulmonary exercise testing (CPET) in healthy volunteers

INTRODUCTION

The performance of a cardiopulmonary exercise test (CPET) requires an individual to undertake a progressive, maximal exercise test to a symptom-limited end point. CPET is commonly performed using a treadmill or cycle ergometer (CE). Arm ergometry (AE) is an alternative exercise modality to CE; however, AE produces lower peak oxygen uptake (V̇O2) values as it involves smaller muscle groups and generates less cardiovascular stress. Current predicted equations for the interpretation of AE CPET are limited by small sample sizes, gender bias and limited age ranges.

AIMS

To develop predicted equations and reference ranges for AE exercise testing.

DESIGN

Incremental ramp protocol CPET, to a symptom-limited end point, via AE was performed in a group of 116 (62 F) healthy volunteers of median age 38 (IQR 29-48) years. Breath-by-breath gas analysis was performed using the Ultima CPX (Medical Graphics, UK) metabolic cart. Quantile regression analysis was used to develop regression equations for AE V̇O2, peak work rate (WR), anaerobic threshold, peak ventilation (VE), peak heart rate, oxygen pulse, V̇E/V̇CO2 slope and V̇O2/WR slope.

RESULTS

Reference equations including upper and/or lower limits, based on quantile regression, were generated and verified using a validation cohort.

CONCLUSIONS

These findings represent the largest and most diverse set of predicted values and reference ranges for AE CPET parameters in healthy individuals to date. Implementation of these reference equations will allow AE to be more widely adopted, enabling the performance and interpretation of CPET in a wider population.

New spirometry recommendations from the Brazilian Thoracic Association - 2024 update

The latest pulmonary function guideline from the Brazilian Thoracic Association was published in 2002, since which there have been updates to international guidelines (mainly those from the European Respiratory Society and the American Thoracic Society), as well as new national and international publications on various aspects of the performance, interpretation, and clinical implications of spirometry. Despite those updates, a careful analysis of what applies to the reality in Brazil is essential, because there have been studies that evaluated individuals who are representative of our population and who could show responses different from those of individuals in other regions of the world. This document is the result of the work of a group of specialists in pulmonary function who evaluated relevant scientific articles that could be applicable to the population of Brazil. After the discussions, new spirometry guidelines were drawn up, covering various aspects such as its technical parameters and performance; its indications and contraindications; its interpretation; concepts of normality and their related variability; reference values; classification of functional severity; and response to an inhaled bronchodilator. Finally, the guidelines emphasize the need to always interpret spirometry results in the context of the clinical condition of the patient and of the pretest probability.

Home high-flow therapy during recovery from severe chronic obstructive pulmonary disease (COPD) exacerbation: a mixed-methods feasibility randomised control trial

INTRODUCTION

Patients recovering from severe acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have a 30-day readmission rate of 20%. This study evaluated the feasibility of conducting a randomised controlled trial to evaluate clinical, patient-reported and physiological effects of home high-flow therapy (HFT) in addition to usual medical therapy, in eucapnic patients recovering from AECOPD to support the design of a phase 3 trial.

METHODS

A mixed-methods feasibility randomised controlled trial (quantitative primacy, concurrently embedded qualitative evaluation) (ISRCTN15949009) recruiting consecutive non-obese patients hospitalised with AECOPD not requiring acute non-invasive ventilation. Participants were randomised to receive usual care or usual care and home HFT (37°C, 30 L/min) with weekly home-based follow-up for 4 weeks to collect data on: device usage, breathlessness (modified Borg scale, visual analogue scale, Multidimensional Dyspnoea Profile), health-related quality of life (COPD Assessment Test (CAT), Clinical COPD Questionnaire), pulse oximetry, spirometry and inspiratory capacity, parasternal electromyography and actigraphy. Semistructured interviews were conducted in week 4. Trial progression criteria were: ≥40% of eligible patients randomised, ≤20% attrition, ≥70% complete data, and no device-related serious adverse events (SAE).

RESULTS

18 of 45 eligible patients were randomised (age 69±5 years, 44% female, body mass index 23±5 kg/m2, forced expiratory volume in 1 second 32±12%). One withdrew following non-respiratory hospitalisation. Complete outcome measures were collected in >90% of home assessments. There were no device-related SAE. Daily HFT usage was 2.7±2.2 hours in week 1, falling to 2.3±1.4 hours by week 4. Temperature and flow settings were modified for comfort in 6 cases. Higher HFT usage was associated with lower symptom burden (CAT p=0.01). Interviews highlighted ease of device use, reduced salbutamol usage, and improved sputum production and clearance.

CONCLUSIONS

The data from this feasibility study support the progression to a phase 3 randomised clinical trial investigating the effect of home (HFT) on admission-free survival in COPD patients recovering from a severe exacerbation.

TRIAL REGISTRATION NUMBER

The study received ethical approval (REC19/LO/0194) and was prospectively registered (ISRCTN15949009).

Unveiling the Influence of AI on Advancements in Respiratory Care: Narrative Review

BACKGROUND

Artificial intelligence is experiencing rapid growth, with continual innovation and advancements in the health care field.

OBJECTIVE

This study aims to evaluate the application of artificial intelligence technologies across various domains of respiratory care.

METHODS

We conducted a narrative review to examine the latest advancements in the use of artificial intelligence in the field of respiratory care. The search was independently conducted by respiratory care experts, each focusing on their respective scope of practice and area of interest.

RESULTS

This review illuminates the diverse applications of artificial intelligence, highlighting its use in areas associated with respiratory care. Artificial intelligence is harnessed across various areas in this field, including pulmonary diagnostics, respiratory care research, critical care or mechanical ventilation, pulmonary rehabilitation, telehealth, public health or health promotion, sleep clinics, home care, smoking or vaping behavior, and neonates and pediatrics. With its multifaceted utility, artificial intelligence can enhance the field of respiratory care, potentially leading to superior health outcomes for individuals under this extensive umbrella.

CONCLUSIONS

As artificial intelligence advances, elevating academic standards in the respiratory care profession becomes imperative, allowing practitioners to contribute to research and understand artificial intelligence's impact on respiratory care. The permanent integration of artificial intelligence into respiratory care creates the need for respiratory therapists to positively influence its progression. By participating in artificial intelligence development, respiratory therapists can augment their clinical capabilities, knowledge, and patient outcomes.

Ultrasonographic modeling of lung and diaphragm mechanics: clinical trial of a novel non-invasive method to evaluate pre-operative pulmonary function

Background

Pre-operative pulmonary function testing (PFT) plays a key role in predicting postoperative complications or functional impairment. However, PFT requires the subject and examiner to cooperate and the results are influenced by both technical and personal factors. In contrast, the use of ultrasound (US) for structural and functional assessments of the lungs and diaphragm is on the rise, as it requires minimal patient cooperation. Dyspnea is mainly caused by lung or pleural lesions but may also be caused by weak respiratory muscles. As the diaphragm is a primary respiratory muscle, combining lung ultrasonography (LUS) with diaphragm ultrasound (DUS) may enable a more comprehensive assessement of pulmonary function. This study aims to introduce a novel approach for assessing pulmonary function using a mathematical model based on LUS and DUS.

Methods

This prospective study was performed at the First Affiliated Hospital of Nanchang University between June 2021 and December 2021, 208 patients were recruited and underwent PFT, LUS, and DUS examinations. An experienced physician, blinded to the clinical history and PFT results, performed LUS and DUS and explored the correlations between a mathematical model (ultrasonographic modeling score (U-score)) using LUS combined with DUS and pulmonary function parameters. Univariate, multivariate, and logistic regression analyses were also performed.

Results

According to the univariate and multivariable analysis, diaphragm thickness fraction in deep breathing (D-DTF) (odds ratio (OR), 0.88; 95% confidence interval (CI) [0.83-0.94]; P < 0.001), and LUS score (OR, 1.44; 95% CI [1.16-1.80]; P < 0.001) were each independently associated with pulmonary function. According to the logistics equation, a U-score of -0.126 × D-DTF + 0.368 × LUS score was produced. The U-score showed a more significant negative correlation with forced expiratory volume in the first second/forced vital capacity (FEV1/FVC) (r = -0.605, P < 0.001) than the LUS or DUS indices alone. The U-score (area under the curve (AUC) = 0.971) was greater than the other indices for assessing pulmonary function.

Conclusions

With validation, the U-score through both lung and diaphragm ultrasound measurements may assist in estimating pulmonary function. This approach facilitates the assessment of pulmonary function in patients who may be unable to reliably participate in PFT.

Effect modification of glycemic control on association of lung function with all-cause and cardiovascular mortality in persons with type 2 diabetes - A retrospective cohort study

BACKGROUND

Poor glucose control might deteriorate the impaired pulmonary function, which can ultimately lead to mortality. However, few studies have examined the effect modification of glucose control on the association between pulmonary function and mortality. This study aimed to examine the association of pulmonary function with mortality and determine the effect modification of glycemic level on the association of pulmonary function with mortality in persons with type 2 diabetes (T2DM).

METHODS

A retrospective cohort study included 3846 persons with T2DM with pulmonary function testing in Taiwan during 2002-2020. Expiratory volume in 1 s (FEV1) was measured as pulmonary function. Cox proportional hazards models were used and the effect modification of pulmonary function parameters and glucose control was assessed by their product terms.

RESULTS

There were 733 deaths during an average follow-up of 7.83 years. Significant associations of FEV1 and mortality were found (hazards ratio [HR] for FEV1 Z-scores of <0 to -1, <-1 to -2 and <-2: 1.47 [1.20, 1.80], 2.48 [1.95, 3.14] and 3.07 [1.74, 5.44] compared with participants with Z-score ≥0, respectively. All p for trend<0.001). Significant effect modifications were found and the association between FEV1 and mortality was stronger in persons with good glycemic control compared with poor glycemic control (FEV1-FPG effect modification, P = 0.01; FEV1-HbA1c effect modification, P = 0.03).

CONCLUSION

Pulmonary function, measured by FEV1, is significantly associated with mortality in persons with T2DM. Significant effect modification of glucose control on the association between pulmonary function parameters and mortality was found.

ERS/ATS Global Lung Function Initiative normal values and classifying severity based on z-scores instead of per cent predicted

Among the most discussed issues in the field of pulmonary function testing are reference equations and standardised methods of interpreting pulmonary function test (PFT) results. The Global Lung Function Initiative (GLI) task force gathered information from multiple countries with diverse ethnicities to create a multi-ethnic reference formula suitable for a broad age range. Their first output was the GLI-2012 spirometry reference equations. Together with the GLI-2012 reference equations, the GLI document recommended the use of z-scores to standardise the interpretation of PFT results. Z-scores were introduced as an alternative to per cent predicted and fixed thresholds in interpreting PFTs. After more than a decade, there is still debate on which method of interpretation is better.

Association of Preserved Ratio Impaired Spirometry with Arterial Stiffness

Rationale: Preserved ratio impaired spirometry (PRISm) is a recently recognized spirometric pattern defined by a ratio of forced expiratory volume in 1 second to forced vital capacity of at least 0.70 and a forced expiratory volume in 1 second  <80% of reference. For unclear reasons, PRISm is associated with increased cardiovascular (CV) morbidity and mortality. Arterial stiffness is a major mechanism of CV disease, which can be measured by carotid-femoral pulse-wave velocity (cfPWV). Objectives: We explored the hypothesis that cfPWV would be increased in individuals with PRISm and airflow limitation (AL). Methods: We measured forced spirometry, lung volumes by body plethysmography, and cfPWV in 9,466 subjects recruited from the general population in the Austrian cross-sectional LEAD (Lung, Heart, Social, Body) study and tested the association of arterial stiffness with PRISm and AL by multivariable linear regression analysis. Individuals younger than 18 years were excluded from the study. Results: Individuals with PRISm (n = 431; 4.6%) were of similar age to those with normal spirometry (n = 8,136; 85.9%) and significantly younger than those with AL (n = 899; 9.5%). Arterial hypertension, diabetes mellitus, coronary artery disease, heart failure, and peripheral arterial occlusive disease were significantly more common in individuals with PRISm than in those with normal lung function and similar to those with AL. There was a significant association between PRISm and arterial stiffness on bivariate linear regression analysis (crude model, β = 0.038; 95% confidence interval [CI], 0.016-0.058), which persisted after robust adjustment for clinical confounders upon multivariable analysis (final model, β = 0.017; 95% CI, 0.001-0.032). cfPWV was significantly higher in individuals with PRISm irrespective of the presence of established CV disease or pulmonary restriction. AL also showed a significant association with arterial stiffness on multivariable linear regression analysis (final model, β = 0.025; 95% CI, 0.009-0.042). Conclusions: Arterial stiffness measured by cfPWV is increased in individuals with PRISm independent of CV disease and risk factors. The pathobiological mechanisms underlying this association deserve further research.

Comparisons between In-Check DIAL® and PF810® in evaluation and training inspiratory capacity for using dry powder inhalers

BACKGROUND

Dry powder inhalers (DPIs) rely on both internal resistance and patients' inspiratory capacity for effective operation. Optimal inspiratory technique is crucial for DPI users. This study assessed the accuracy and repeatability of two available devices, PF810® and In-Check DIAL®, and analyzed their measurement errors and consistency in detecting inspiratory capacity.

METHODS

The accuracy and repeatability of peak inspiratory flow (PIF) and forced inspiratory vital capacity (FIVC) against various internal resistances of the two devices were assessed using standard waveforms generated by a breathing simulator. The agreement of PIF measurements between the two devices in healthy volunteers and chronic obstructive pulmonary disease (COPD) patients was analyzed with the intraclass correlation coefficient and Bland-Altman graphical analysis.

RESULTS

PF810® showed great accuracy and repeatability in measuring PIF, except for square waveforms at the lowest flow rate (20 L/min). In-Check DIAL® exhibited poor accuracy against high resistance levels. In scenarios with no resistance, In-Check DIAL® had significantly smaller measurement errors than PF810®, but larger errors against high resistance levels. The two devices showed excellent agreement (ICC > 0.80, P < 0.05), except for healthy volunteers against medium to high resistance (R3-R5) where the ICC was insignificant. Bland-Altman plots indicated small disagreements between the two devices for both healthy volunteers and COPD patients.

CONCLUSIONS

In-Check DIAL® exhibited poor accuracy and larger measurement errors than PF810® when detecting PIFs against higher internal resistances. However, its good performance against lower internal resistances, along with its cost-effectiveness and convenience made it appropriate for primary care. PF810® showed good accuracy and repeatability and could detect additional parameters of inspiratory capacity beyond PIF, though required further studies to confirm its clinical benefits.

Impact of environmental air pollution on respiratory health and function

Environmental air pollution presents a considerable risk to global respiratory health. If critical levels are exceeded, inhaled pollutants can lead to the development of respiratory dysfunction and provoke exacerbation in those with pre-existing chronic respiratory disease. Over 90% of the global population currently reside in areas where environmental air pollution is considered excessive-with adverse effects ranging from acute airway irritation to complex immunomodulatory alterations. This narrative review provides an up-to-date perspective concerning the impact of environmental air pollution on respiratory health and function and describes the underpinning mechanisms that contribute to the development and progression of chronic respiratory disease.

Assessing the Impact of Non-Exhaust Emissions on the Asthmatic Airway (IONA) Protocol for a Randomised Three-Exposure Crossover Study

BACKGROUND

People living with asthma are disproportionately affected by air pollution, with increased symptoms, medication usage, hospital admissions, and the risk of death. To date, there has been a focus on exhaust emissions, but traffic-related air pollution (TRAP) can also arise from the mechanical abrasion of tyres, brakes, and road surfaces. We therefore created a study with the aim of investigating the acute impacts of non-exhaust emissions (NEEs) on the lung function and airway immune status of asthmatic adults.

METHODS

A randomised three-condition crossover panel design will expose adults with asthma using a 2.5 h intermittent cycling protocol in a random order at three locations in London, selected to provide the greatest contrast in the NEE components within TRAP. Lung function will be monitored using oscillometry, fractional exhaled nitric oxide, and spirometry (the primary outcome is the forced expiratory volume in one second). Biomarkers of inflammation and airborne metal exposure will be measured in the upper airway using nasal lavage. Symptom responses will be monitored using questionnaires. Sources of exhaust and non-exhaust concentrations will be established using source apportionment via the positive matrix factorisation of high-time resolution chemical measures conducted at the exposure sites.

DISCUSSION

Collectively, this study will provide us with valuable information on the health effects of NEE components within ambient PM2.5 and PM10, whilst establishing a biological mechanism to help contextualise current epidemiological observations.

The impact of gas transfer on responses to exercise training in patients with pulmonary hypertension

Exercise training is recommended for pulmonary hypertension (PH). Post hoc analysis of the PH and Home-Based (PHAHB) trial stratified patients into two groups based on median diffusing capacity of the lungs for carbon monoxide (DLCO). Patients with higher DLCO had a greater improvement in physical activity performance in response to exercise training, compared to those with lower DLCO. DLCO may be an important consideration in prescribing exercise in PH.

Development of respiratory care guidelines for Duchenne muscular dystrophy in the UK: key recommendations for clinical practice

Significant inconsistencies in respiratory care provision for Duchenne muscular dystrophy (DMD) are reported across different specialist neuromuscular centres in the UK. The absence of robust clinical evidence and expert consensus is a barrier to the implementation of care recommendations in public healthcare systems as is the need to increase awareness of key aspects of care for those living with DMD. Here, we provide evidenced-based and/or consensus-based best practice for the respiratory care of children and adults living with DMD in the UK, both as part of routine care and in an emergency.

METHODOLOGY

Initiated by an expert working group of UK-based respiratory physicians (including British Thoracic Society (BTS) representatives), neuromuscular clinicians, physiotherapist and patient representatives, draft guidelines were created based on published evidence, current practice and expert opinion. After wider consultation with UK respiratory teams and neuromuscular services, consensus was achieved on these best practice recommendations for respiratory care in DMD.

RESULT

The resulting recommendations are presented in the form of a flow chart for assessment and monitoring, with additional guidance and a separate chart setting out key considerations for emergency management. The recommendations have been endorsed by the BTS.

CONCLUSIONS

These guidelines provide practical, reasoned recommendations for all those managing day-to-day and acute respiratory care in children and adults with DMD. The hope is that this will support patients and healthcare professionals in accessing high standards of care across the UK.

Carotid body dysregulation contributes to Long COVID symptoms

BACKGROUND

The symptoms of long COVID, which include fatigue, breathlessness, dysregulated breathing, and exercise intolerance, have unknown mechanisms. These symptoms are also observed in heart failure and are partially driven by increased sensitivity of the carotid chemoreflex. As the carotid body has an abundance of ACE2 (the cell entry mechanism for SARS-CoV-2), we investigated whether carotid chemoreflex sensitivity was elevated in participants with long COVID.

METHODS

Non-hositalised participants with long-COVID (n = 14) and controls (n = 14) completed hypoxic ventilatory response (HVR; the measure of carotid chemoreflex sensitivity) and cardiopulmonary exercise tests. Parametric and normally distributed data were compared using Student's unpaired t-tests or ANOVA. Nonparametric equivalents were used where relevant. Peason's correlation coefficient was used to examine relationships between variables.

RESULTS

During cardiopulmonary exercise testing the VE/VCO2 slope (a measure of breathing efficiency) was higher in the long COVID group (37.8 ± 4.4) compared to controls (27.7 ± 4.8, P = 0.0003), indicating excessive hyperventilation. The HVR was increased in long COVID participants (-0.44 ± 0.23 l/min/ SpO2%, R2 = 0.77 ± 0.20) compared to controls (-0.17 ± 0.13 l/min/SpO2%, R2 = 0.54 ± 0.38, P = 0.0007). The HVR correlated with the VE/VCO2 slope (r = -0.53, P = 0.0036), suggesting that excessive hyperventilation may be related to carotid body hypersensitivity.

CONCLUSIONS

The carotid chemoreflex is sensitised in long COVID and may explain dysregulated breathing and exercise intolerance in these participants. Tempering carotid body excitability may be a viable treatment option for long COVID patients.

Breathing a low-density gas reduces respiratory muscle force development and marginally improves exercise performance in master athletes

INTRODUCTION

We tested the hypothesis that breathing heliox, to attenuate the mechanical constraints accompanying the decline in pulmonary function with aging, improves exercise performance.

METHODS

Fourteen endurance-trained older men (67.9 ± 5.9 year, [Formula: see text]O2max: 50.8 ± 5.8 ml/kg/min; 151% predicted) completed two cycling 5-km time trials while breathing room air (i.e., 21% O2-79% N2) or heliox (i.e., 21% O2-79% He). Maximal flow-volume curves (MFVC) were determined pre-exercise to characterize expiratory flow limitation (EFL, % tidal volume intersecting the MFVC). Respiratory muscle force development was indirectly determined as the product of the time integral of inspiratory and expiratory mouth pressure (∫Pmouth) and breathing frequency. Maximal inspiratory and expiratory pressure maneuvers were performed pre-exercise and post-exercise to estimate respiratory muscle fatigue.

RESULTS

Exercise performance time improved (527.6 ± 38 vs. 531.3 ± 36.9 s; P = 0.017), and respiratory muscle force development decreased during inspiration (- 22.8 ± 11.6%, P < 0.001) and expiration (- 10.8 ± 11.4%, P = 0.003) with heliox compared with room air. EFL tended to be lower with heliox (22 ± 23 vs. 30 ± 23% tidal volume; P = 0.054). Minute ventilation normalized to CO2 production ([Formula: see text]E/[Formula: see text]CO2) increased with heliox (28.6 ± 2.7 vs. 25.1 ± 1.8; P < 0.001). A reduction in MIP and MEP was observed post-exercise vs. pre-exercise but was not different between conditions.

CONCLUSIONS

Breathing heliox has a limited effect on performance during a 5-km time trial in master athletes despite a reduction in respiratory muscle force development.

Lung function responses to cold water ingestion: A randomised controlled crossover trial

This study tested the hypothesis that cold water ingestion would reduce lung function and thereby confound its measurement in a way that is mediated by both temperature and volume. In a randomised crossover trial, 10 healthy adults performed spirometry before and 5, 10, 15, and 30-minutes after consuming one-of-four drinks: 500 mL or 1000 mL refrigerated water (∼2 °C); identical water volumes at ambient temperature (∼18 °C). Ingesting 1000 mL cold water significantly reduced forced vital capacity (FVC) for at least 10 min (mean difference =0.28 L, p < 0.05, d=1.19) and forced expiratory volume in 1 s (FEV1) for at least 15 min (0.20-0.30 L, p < 0.05, d=1.01). Ingesting 500 mL cold water reduced FEV1 for 5 min (0.09 L, p < 0.05, d=1.05). Room-temperature water had no influence on lung function. To avoid confounding the measurement of lung function, we conclude that individuals should avoid drinking cold water, especially in large volumes, immediately prior to a given test.

Effectiveness of a cardiac rehabilitation program on biomechanical, imaging, and physiological biomarkers in elderly patients with heart failure with preserved ejection fraction (HFpEF): FUNNEL + study protocol

BACKGROUND

Patients with heart failure with preserved ejection fraction (HFpEF) have a low functional status, which in turn is a risk factor for hospital admission and an important predictor of survival in HFpEF. HFpFE is a heterogeneous syndrome and recent studies have suggested an important role for careful, pathophysiological-based phenotyping to improve patient characterization. Cardiac rehabilitation has proven to be a useful tool in the framework of secondary prevention in patients with HFpEF. Facilitating decision-making and implementing cardiac rehabilitation programs is a challenge in public health systems for HFpEF management. The FUNNEL + study proposes to evaluate the efficacy of an exercise and education-based cardiac rehabilitation program on biomechanical, physiological, and imaging biomarkers in patients with HFpEF.

METHODS

A randomised crossover clinical trial is presented among people older than 70 years with a diagnosis of HFpEF. The experimental group will receive a cardiac rehabilitation intervention for 12 weeks. Participants in the control group will receive one educational session per week for 12 weeks on HFpEF complications, functional decline, and healthy lifestyle habits. VO2peak is the primary outcome. Biomechanical, imaging and physiological biomarkers will be assessed as secondary outcomes. Outcomes will be assessed at baseline, 12 weeks, and 24 weeks.

DISCUSSION

Identifying objective functional parameters indicative of HFpEF and the subsequent development of functional level stratification based on functional impairment ("biomechanical phenotypes") may help clinicians identify cardiac rehabilitation responders and non-responders and make future clinical decisions. In this way, future pharmacological and non-pharmacological interventions, such as exercise, could be improved and tailored to improve quality of life and prognosis and reducing patients' hospital readmissions, thereby reducing healthcare costs.

TRIAL REGISTRATION

NCT05393362 (Clinicaltrials.gov).

Feasibility and value of a domiciliary spirometry programme in the assessment of severe asthma: a real-world evaluation

Background

Domiciliary spirometry (DS) is a novel tool that is widely employed in the assessment of respiratory disease. We assessed real-world feasibility, effectiveness and value of a physiologist-led home spirometry programme in patients with treatment-refractory severe asthma.

Methods

Patients were referred and provided with a hand-held DS device. Patients completed baseline measurements in a physiologist-led virtual clinic and were instructed to provide further values during any periods of respiratory symptoms. Outcome measures included prevalence of new obstructed events, DS adherence and uptake of this approach.

Results

112 patients were enrolled from November 2020 to January 2023. 102 individuals, mean±sd age 44±13 years (86% female) with median (IQR) forced expiratory volume in 1 s % predicted 88% (77-97%), successfully recorded baseline spirometry values. During follow-up (24 months), 11 (11%) were identified with new obstructive spirometry and were subsequently able to be commenced on biologic therapy. Patient engagement was poor with median (IQR) of 4 (2-6) attempts of contact made before baseline values were recorded, and 2 (1-3) attempts required to record technically acceptable values. Continued DS use was suboptimal; 34% failed to use their device after baseline and only 10% continued at the end of the study period. The cost of DS measurements was greater than a single hospital-based visit but enables multiple event capture.

Conclusion

Overall, DS measurement uptake was poor, with a minority of patients continuing to use the device at the end of the study period. However, for those that engage, DS provides an alternative approach to traditional hospital-based spirometry measurements that can alter clinical management.

European Respiratory Society/American Thoracic Society technical statement: standardisation of the measurement of lung volumes, 2023 update

This document updates the 2005 European Respiratory Society (ERS) and American Thoracic Society (ATS) technical standard for the measurement of lung volumes. The 2005 document integrated the recommendations of an ATS/ERS task force with those from an earlier National Heart, Lung, and Blood Institute workshop that led to the publication of background papers between 1995 and 1999 and a consensus workshop report with more in-depth descriptions and discussion. Advancements in hardware and software, new research and emerging approaches have necessitated an update to the 2005 technical standard to guide laboratory directors, physiologists, operators, pulmonologists and manufacturers. Key updates include standardisation of linked spirometry, new equipment quality control and validation recommendations, generalisation of the multiple breath washout concept beyond nitrogen, a new acceptability and grading system with addition of example tracings, and a brief review of imaging and other new techniques to measure lung volumes. Future directions and key research questions are also noted.

Small airways dysfunction: The importance of utilising Z-scores to define MMEF abnormalities in clinical practice

Background

The small airways comprise the largest cross-sectional area of the lungs, however, assessing and reporting abnormalities for this region of the bronchial tree has been practically and scientifically uncertain.

Methods

Using routinely collected spirometry data for patients with either asthma or COPD, the accuracy of % predicted values for defining small airways dysfunction was assessed. A z-score of ≤ -1.645 of the maximal-mid expiratory flow (MMEF) was used as the gold standard for defining abnormality in the small airways.

Results

Records of 3396 patients were included in the analysis. The false positive (FP) rates were 24.6 %, 16.1 %, 11.5 %, or 7.9 % when the % predicted value of 80 %, 70 %, 65 %, or 60 % were used, respectively. Sex, age, and BMI were associated with FP rates. Males were more likely to be categorised as FP with odds ratio (OR) between 1.10 and 1.49 across % predicted groups. Age was associated with FP rates with an OR between 1.01 and 1.08. The BMI was also associated with FP rates with an OR of 1.03 across all % predicted groups. Assessing the association of age groups with FP rate showed that those above 60 years old were more likely to be categorised as FP with an OR between 1.23 and 73.2 compared to those less than 30 years old.

Conclusion

When assessing the small airways in clinical practice or for scientific purposes, the % predicted values overestimate the actual impairment leading to FP interpretation. Utilising z-score values are recommended to assess the small airways using the spirometric index, MMEF.

DLCO Biologic Quality-Control Findings From a Multi-Center Global Study

BACKGROUND

The 2017 American Thoracic Society/European Respiratory Society (ATS/ERS) diffusing capacity of the lung for carbon monoxide (DLCO) standards specify a control rule for assessing biologic quality control (BioQC) but have limited guidance on how to establish expected values for control rule variables. This study aimed to determine expected values for DLCO BioQC using coefficient of variation (CV) and compare that the mean ± 2 SD control rule yields the same precision as mean ± 12% of the mean.

METHODS

DLCO BioQC data were collected from a multi-center inhaled medication study. This descriptive study spanned 42 months ending in 2018. The annual DLCO CV was based upon 10 DLCO values separated by at least 5 d. The root mean square CV (RMSCV) was computed for each year and Friedman test evaluated within subject annual CV changes. Ninetieth percentile values were computed for annual control rule limits/mean DLCO.

RESULTS

Of 217 BioQCs, the study's first year had 168 subjects with fewer in subsequent years. Annual CV values from RMSCV were 5.3, 4.5, and 4.6% in years 1, 2, and 3, respectively. No change was seen in the CV for those subjects with data for all 3 years, n = 24, P = .07. The 90th percentile of measurements 2 SD/mean DLCO were 15, 12.4, and 11% in years 1, 2, and 3, respectively.

CONCLUSIONS

A DLCO BioQC CV ≤ 6% is achievable across multiple sites, technologists, and brands of equipment. This CV value assures that measurements for control rule variables emerge from an expected range. A control rule of mean ± 2 SD appeared to yield similar results as the mean ± 12% of the mean rule reported in the 2017 ATS/ERS DLCO standards.

Can spirometry improve the performance of cardiovascular risk model in high-risk Eastern European countries?

Aims

Impaired lung function has been strongly associated with cardiovascular disease (CVD) events. We aimed to assess the additive prognostic value of spirometry indices to the risk estimation of CVD events in Eastern European populations in this study.

Methods

We randomly selected 14,061 individuals with a mean age of 59 ± 7.3 years without a previous history of cardiovascular and pulmonary diseases from population registers in the Czechia, Poland, and Lithuania. Predictive values of standardised Z-scores of forced expiratory volume measured in 1 s (FEV1), forced vital capacity (FVC), and FEV1 divided by height cubed (FEV1/ht3) were tested. Cox proportional hazards models were used to estimate hazard ratios (HRs) of CVD events of various spirometry indices over the Framingham Risk Score (FRS) model. The model performance was evaluated using Harrell's C-statistics, likelihood ratio tests, and Bayesian information criterion.

Results

All spirometry indices had a strong linear relation with the incidence of CVD events (HR ranged from 1.10 to 1.12 between indices). The model stratified by FEV1/ht3 tertiles had a stronger link with CVD events than FEV1 and FVC. The risk of CVD event for the lowest vs. highest FEV1/ht3 tertile among people with low FRS was higher (HR: 2.35; 95% confidence interval: 1.96-2.81) than among those with high FRS. The addition of spirometry indices showed a small but statistically significant improvement of the FRS model.

Conclusions

The addition of spirometry indices might improve the prediction of incident CVD events particularly in the low-risk group. FEV1/ht3 is a more sensitive predictor compared to other spirometry indices.

The role of lung volume recruitment therapy in neuromuscular disease: a narrative review

Respiratory muscle weakness results in substantial discomfort, disability, and ultimately death in many neuromuscular diseases. Respiratory system impairment manifests as shallow breathing, poor cough and associated difficulty clearing mucus, respiratory tract infections, hypoventilation, sleep-disordered breathing, and chronic ventilatory failure. Ventilatory support (i.e., non-invasive ventilation) is an established and key treatment for the latter. As survival outcomes improve for people living with many neuromuscular diseases, there is a shift towards more proactive and preventative chronic disease multidisciplinary care models that aim to manage symptoms, improve morbidity, and reduce mortality. Clinical care guidelines typically recommend therapies to improve cough effectiveness and mobilise mucus, with the aim of averting acute respiratory compromise or respiratory tract infections. Moreover, preventing recurrent infective episodes may prevent secondary parenchymal pathology and further lung function decline. Regular use of techniques that augment lung volume has similarly been recommended (volume recruitment). It has been speculated that enhancing lung inflation in people with respiratory muscle weakness when well may improve respiratory system "flexibility", mitigate restrictive chest wall disease, and slow lung volume decline. Unfortunately, clinical care guidelines are based largely on clinical rationale and consensus opinion rather than level A evidence. This narrative review outlines the physiological changes that occur in people with neuromuscular disease and how these changes impact on breathing, cough, and respiratory tract infections. The biological rationale for lung volume recruitment is provided, and the clinical trials that examine the immediate, short-term, and longer-term outcomes of lung volume recruitment in paediatric and adult neuromuscular diseases are presented and the results synthesised.

Cardiorespiratory fitness as a vital sign of CVD risk in the COVID-19 era

The severe health consequences of the corona virus disease 2019 (COVID-19) pandemic have been exacerbated by the prevalence of cardiovascular disease (CVD) risk factors, such as physical inactivity, obesity, hypertension, and diabetes. Further, policy decisions during the pandemic augmented unhealthy lifestyle behaviors and health inequalities, likely increasing the global disease burden. Cardiorespiratory fitness (CRF) is a well-established biomarker associated with CVD risk. Emerging data demonstrate that high CRF offers some protection against severe outcomes from COVID-19 infection, highlighting the importance of CRF for population health and the potential for limiting the severity of future pandemics. CRF is best assessed by cardiopulmonary exercise testing (CPET), which will be an important tool for understanding the prolonged pathophysiology of COVID-19, the emergence of long-COVID, and the lasting effects of COVID-19 on CVD risk. Utilization of CRF and CPET within clinical settings should become commonplace because of lessons learned from the COVID-19 pandemic.

The prevalence of bronchodilator responsiveness of the small airway (using mid-maximal expiratory flow) in COPD - a retrospective study

BACKGROUND

Bronchodilator responsiveness (BDR) using FEV₁ is often utilised to separate COPD patients from asthmatics, although it can be present in some COPD patients. With the advent of treatments with distal airway deposition, BDR in the small airways (SA) may be of value in the management of COPD. We aimed to identify the prevalence of BDR in the SA, utilizing maximal mid-expiratory flow (MMEF) as a measure of SA. We further evaluated the prevalence of BDR in MMEF with and without BDR in FEV₁ and its association with baseline demographics, including conventional airflow obstruction severity and smoking history.

METHODS

Lung function data of ever-smoking COPD patients were retrospectively analysed. BDR was evaluated 20 min after administering 2.5 mg of salbutamol via jet nebulizer. Increase in percent change of ≥ 12% and absolute change of ≥ 200 ml was used to define a BDR in FEV₁, whereas an increase percent change of MMEF ≥ 30% was used to define a BDR in MMEF. Patients were classified as one of three groups according to BDR levels: group 1 (BDR in MMEF and FEV₁), group 2 (BDR in MMEF alone) and group 3 (no BDR in either measure).

RESULT

BDR in MMEF was present in 59.2% of the patients. Of note, BDR in MMEF was present in all patients with BDR in FEV₁ (group 1) but also in 37.9% of the patients without BDR in FEV₁ (group 2). Patients in group 1 were younger than in groups 2 and 3. BMI was higher in group 1 than in group 3. Baseline FEV₁% predicted and FVC % predicted were also higher in groups 1 and 2 than in group 3.

CONCLUSION

BDR in the SA (evaluated by MMEF) is common in COPD, and it is also feature seen in all patients with BDR in FEV₁. Even in the absence of BDR in FEV₁, BDR in MMEF is detected in some patients with COPD, potentially identifying a subgroup of patients who may benefit from different treatment strategies.

Long-term improvement of air quality associated with lung function benefits in Chinese young adults: A quasi-experiment cohort study

INTRODUCTION

Long-term exposure to air pollution is associated with lung function impairment. However, whether long-term improvements in air quality could improve lung function is unclear.

OBJECTIVES

To examine whether the reduction of long-term air pollution was associated with lung function improvement among Chinese young adults.

METHODS

We conducted a prospective quasi-experiment cohort study with 1731 college students in Shandong, China from September 2019 to September 2020, covering COVID-19 lockdown period. Data on air pollution concentrations were obtained from China Environmental Monitoring Station. Lung function indicators included forced vital capacity (FVC), forced expiratory volume in 1st second (FEV₁) and forced expiratory flow at 50 % of FVC (FEF50%). We used linear mixed-effects model to examine the associations between the change of air pollutants concentrations and the change of lung function, and additional adjustments for indoor air pollution (IAP) source. We also conducted stratified analysis by sex.

RESULTS

Compared with 2019, the mean FVC, FEV₁ and FEF50% were elevated by 414.4 ml, 321.5 ml, and 28.4 ml/s respectively in 2020. Every 5 μg/m³ decrease in annual average PM_2.5 concentrations was associated with 36.0 ml [95 % confidence interval (CI):6.0, 66.0 ml], 46.1 ml (95 % CI:16.7, 75.5 ml), and 124.2 ml/s (95 % CI:69.5, 178.9 ml/s) increment in the FVC, FEV₁, and FEF50%, respectively. Similar associations were found for PM₁₀. The estimated impact was almost unchanged after adjusting for IAP source. There was no significant effect difference between males and females.

CONCLUSION

Long-term improvement of air quality can improve lung function among young adults. Stricter policies on improving air quality are needed to protect human health.

Small airway function measured using forced expiratory flow between 25% and 75% of vital capacity and its relationship to airflow limitation in symptomatic ever-smokers: a cross-sectional study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is diagnosed and its severity graded by traditional spirometric parameters (forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) and FEV₁, respectively) but these parameters are considered insensitive for identifying early pathology. Measures of small airway function, including forced expiratory flow between 25% and 75% of vital capacity (FEF_25-75), may be more valuable in the earliest phases of COPD. This study aimed to determine the prevalence of low FEF_25-75 in ever-smokers with and without airflow limitation (AL) and to determine whether FEF_25-75 relates to AL severity.

METHOD

A retrospective analysis of lung function data of 1458 ever-smokers suspected clinically of having COPD. Low FEF_25-75 was defined by z-score<-0.8345 and AL was defined by FEV₁/FVC z-scores<-1.645. The severity of AL was evaluated using FEV₁ z-scores. Participants were placed into three groups: normal FEF_25-75/ no AL (normal FEF_25-75/AL-); low FEF_25-75/ no AL (low FEF_25-75/AL-) and low FEF_25-75/ AL (low FEF_25-75/AL+).

RESULTS

Low FEF_25-75 was present in 99.9% of patients with AL, and 50% of those without AL. Patients in the low FEF_25-75/AL- group had lower spirometric measures (including FEV₁ FEF_25-75/FVC and FEV₃/FVC) than those in the normal FEF_25-75/AL- group. FEF_25-75 decreased with AL severity. A logistic regression model demonstrated that in the absence of AL, the presence of low FEF_25-75 was associated with lower FEV₁ and FEV₁/FVC even when smoking history was accounted for.

CONCLUSIONS

Low FEF_25-75 is a physiological trait in patients with conventional spirometric AL and likely reflects early evidence of impairment in the small airways when spirometry is within the 'normal range'. FEF_25-75 likely identifies a group of patients with early evidence of pathological lung damage who warrant careful monitoring and reinforced early intervention to abrogate further lung injury.

JC, Katznelson R. The role of routine pulmonary imaging before hyperbaric oxygen treatment

Respiratory injury during or following hyperbaric oxygen treatment (HBOT) is rare, but associated pressure changes can cause iatrogenic pulmonary barotrauma with potentially severe sequelae such as pneumothoraces. Pulmonary blebs, bullae, and other emphysematous airspace abnormalities increase the risk of respiratory complications and are prevalent in otherwise healthy adults. HBOT providers may elect to use chest X-ray routinely as a pre-treatment screening tool to identify these anomalies, particularly if a history of preceding pulmonary disease is identified, but this approach has a low sensitivity and frequently provides false negative results. Computed tomography scans offer greater sensitivity for airspace lesions, but given the high prevalence of incidental and insignificant pulmonary findings among healthy individuals, would lead to a high false positive rate because most lesions are unlikely to pose a hazard during HBOT. Post-mortem and imaging studies of airspace lesion prevalence show that a significant proportion of patients who undergo HBOT likely have pulmonary abnormalities such as blebs and bullae. Nevertheless, pulmonary barotrauma is rare, and occurs mainly in those with known underlying lung pathology. Consequently, routinely using chest X-ray or computed tomography scans as screening tools prior to HBOT for low-risk patients without a pertinent medical history or lack of clinical symptoms of cardiorespiratory disease is of low value. This review outlines published cases of patients experiencing pulmonary barotrauma while undergoing pressurised treatment/testing in a hyperbaric chamber and analyses the relationship between barotrauma and pulmonary findings on imaging prior to or following exposure. A checklist and clinical decision-making tool based on suggested low-risk and high-risk features are offered to guide the use of targeted baseline thoracic imaging prior to HBOT.

Impact of mannose-binding lectin gene polymorphism on lung functions among workers exposed to airborne Aspergillus in a wastewater treatment plant in Egypt

In this study, the risk of Aspergillus (Asp.) positivity and its respiratory health impacts on wastewater treatment plant (WWTP) workers were studied. In addition, it identified the geno-susceptibility role of mannose-binding lectin 2 (MBL2) gene polymorphisms and the mannose-binding lectin (MBL) serum levels on the pulmonary functions of the Asp.-positive workers. Pulmonary function tests (PFTs) were performed for 89 workers from a selected WWTP, after exclusion of the smokers. Molecular identification of Asp. blood positivity was done by 18S rRNA sequencing. Determination of MBL2 gene polymorphism and estimation of MBL serum levels were done. PFTs revealed abnormalities in 49.2% of the workers. Asp. was positive in 42.5% of the workers with different species. Among the Asp.-positive workers, 6.5% of the workers were with obstructive PFTs, 12.9% with restriction, and 22.6% with combined PFT abnormalities. MBL2 genotyping showed that wild genotype AA was common (68.5%) among Asp.-positive workers compared to the other genotypes. This allele, whether homozygous or heterozygous, was significantly associated with decline in PFTs of the exposed workers. MBL serum levels were significantly lower in workers with obstructive, restrictive, and combined PFT abnormalities compared to those with normal PFTs, and in the workers with Asp.-positive species than the Asp.-negative workers. Moreover, it was significantly lower in workers with Asp. fumigatus compared to that in the workers with other Asp. species, and in the Asp.-positive workers with homozygous or heterozygous A allele compared to that in the Asp.-positive workers with homozygous B allele. Working in a WWTP can be associated with impaired PFTs due to exposure to airborne fungi. MBL2 genotyping showed that Asp.-positive workers with homozygous or heterozygous A allele were at risk to develop decline in their PFTs.

Respiratory Function and Sleep Disordered Breathing in Pediatric Duchenne Muscular Dystrophy

BACKGROUND

The decline of respiratory function in Duchenne muscular dystrophy (DMD) is associated with sleep disordered breathing (SDB) and alteration of nocturnal gas exchange, first manifesting as nocturnal hypoventilation (NH). However, the correlation between pulmonary function measured by spirometry (PFT) and the onset of SDB with or without NH is unclear.

AIM

To identify the prevalence and features of SDB and to investigate the relationship between lung function determined by forced vital capacity (FVC) and sleep abnormalities in a large paediatric DMD population.

METHODS

Retrospective, single-center cohort study. FVC% predicted (FVC%) was calculated using predicted equations from the Global Lung Function Initiative. NH was defined by transcutaneous (tc) CO2 >50 mmHg for >25% of total sleep time (TST); borderline NH by a mean tcCO2 between 45-50mmHg or tcCO2>50mmHg for ≤25% of TST; Clinically meaningful obstructive sleep apnea (OSA) by obstructive Apnea-Hypopnea Index >5. The sensitivity, specificity, positive and negative predictive value of FVC<50% to indicate presence of nocturnal hypoventilation were calculated.

RESULTS

134 patients underwent 284 sleep studies and 1222 PFT. Mean (SD) age at first and last sleep study was 12.9 (2.7) and 14.3 (2.6) years. Borderline NH (n=31) was detected in both ambulant and early-non ambulant subjects, while 100% of NH cases (n=14) were non-ambulant. NH was detected in 4/14 patients despite an FVC>50%. Seventeen/26 patients with OSA presented with concomitant NH or borderline NH. FVC<50% was associated with NH indicating a sensitivity and specificity of 73% and 86%, respectively. Positive and negative predictive value were 32% and 97% respectively. PFT showed a non-linear, sudden FVC% decline in 18% of cases.

CONCLUSIONS

FVC% <50 was associated with NH in close to a third of patients. CO2 elevation can be associated with obstructive/pseudo-obstructive events and was also observed in early non-ambulant cases or in the presence of FVC>50%. These results are relevant for the clinical management of SDB.

All-cause and cardiovascular mortality in relation to lung function in the full range of distribution across four Eastern European cohorts

It is unclear whether the dose-response relationship between lung function and all-cause and cardiovascular mortality in the Central and Eastern European populations differ from that reported in the Western European and American populations. We used the prospective population-based HAPIEE cohort that includes randomly selected people with a mean age of 59 ± 7.3 years from population registers in Czech, Polish, Russian and Lithuanian urban centres. The baseline survey in 2002-2005 included 36,106 persons of whom 24,944 met the inclusion criteria. Cox proportional hazards models were used to estimate the dose-response relationship between lung function defined as FEV1 divided by height cubed and all-cause and cardiovascular mortality over 11-16 years of follow-up. Mortality rate increased in a dose-response manner from highest to lower FEV1/height3 deciles. Adjusted hazard ratios (HR) of all-cause mortality for persons in the 8th best, the 5th and the worst deciles were 1.27 (95% CI 1.08‒1.49), 1.37 (1.18-1.60) and 2.15 (1.86‒2.48), respectively; for cardiovascular mortality, the respective HRs were 1.84 (1.29-2.63), 2.35 (1.67-3.28) and 3.46 (2.50‒4.78). Patterns were similar across countries, with some statistically insignificant variation. FEV1/height3 is a strong predictor of all-cause and cardiovascular mortality, across full distribution of values, including persons with preserved lung function.

Effects of Addition of Inspiratory Muscle Training to Exercise-Based Cardiac Rehabilitation on Inspiratory Muscle Strength, Peak Oxygen Consumption, and Selected Hemodynamics in Chronic Heart Failure

Background

Evidence supports the clinical benefits of isolated inspiratory muscle training (IMT) in patients with chronic heart failure (CHF); however, the rationale of IMT in combination with exercise training in cardiac rehabilitation settings for CHF has yet to be confirmed.

Objective

This study aimed to assess the effect of the addition of IMT in combination with aerobic/resistance training (AT/RT) on maximal inspiratory pressure (PImax), peak oxygen consumption (VO2peak), selected hemodynamic variables, and health-related quality of life (HRQoL) compared to sham-IMT combined with AT/RT in patients with CHF.

Methods

Twenty-five male patients with CHF completed a 6-month cardiac rehabilitation program of either a sham-IMT/AT/RT program (control group, 51.84 ± 4.56 years old, n1 = 13), or a real-IMT/AT/RT program (study group, 51.75 ± 4.73 years old, n2 = 12). Inclusion criteria were ischemic heart failure, New York Heart Association (NYHA) class II-III, and reduced ejection fraction. Outcome measures were PImax, VO2peak, resting heart rate (RHR), heart rate (HR) reserve, rate pressure product (RPP), left-ventricular ejection fraction, and Minnesota Living with Heart Failure Questionnaire (MLwHFQ). Absolute mean changes from baseline (Δ) in the outcome measures were statistically analyzed as independent outcomes.

Results

ΔPImax, ΔRHR, ΔHR reserve, and ΔMLwHFQ total score were significantly greater in the study group than in the control group (p < 0.05). In addition, ΔRPP showed an observed difference in favor of the study group with a tendency towards statistical significance (p = 0.07).

Conclusions

IMT could be a successful complementary intervention to exercise-based cardiac rehabilitation programs comprising AT/RT, yielding greater improvements in PImax, RHR, HR reserve, and HRQoL in male patients with ischemic heart failure (NYHA class II-III).

Variations in FVC and FEV1 Biologic Quality Control Measures in a Global Multi-Center Clinical Trial

BACKGROUND

Although quality control standards are recommended to ensure accurate test results, the coefficient of variation for the FVC and FEV₁ biologic quality control (BioQC) is not specified. The primary aim of this study was to evaluate variations in spirometry BioQCs in a large and diverse cohort of individuals to determine an acceptable standard for the coefficient of variation.

METHODS

The FVC and FEV₁ biologic control data were secondary analyses from an inhaled medication trial that was conducted over 3 y ending in 2018 that included 114 laboratories. Results were sent to a central repository for expert review. The FVC and FEV₁ coefficients of variation were based upon a minimum of 10 spirometry values annually separated by at least 5 d. A second method of computing the coefficient of variation used 10 values within 28 d. Descriptive statistics were computed. Wilcoxon signed-rank tests were conducted to compare whether the median coefficient of variation values between the 2 methods differed, tested at α = 0.05 using SPSS.

RESULTS

Of 249 biologic control participants, 170 met the first year's inclusion criteria. The coefficient of variation for the 5-d separated method was < 5% for 94.1% of FVC and 93.5% of FEV₁ values in the first year. By year 3, 90% of FVC and FEV₁ coefficient of variation values were < 4%. The medians for the 5-d separated and the 28-d measure showed no difference for either FVC coefficient of variation or FEV₁ coefficient of variation, Z = -1.764, P = .78, and Z = -0.980, P = .33, respectively.

CONCLUSIONS

Interlab biologic control variation values of < 4% for FVC and FEV₁ are achievable; however, individual labs should strive to attain lower values. Acceptable coefficients of variation can be achieved within 28 d.

Impaired lung function and mortality in Eastern Europe: results from multi-centre cohort study

BACKGROUND

The association between impaired lung function and mortality has been well documented in the general population of Western European countries. We assessed the risk of death associated with reduced spirometry indices among people from four Central and Eastern European countries.

METHODS

This prospective population-based cohort includes men and women aged 45-69 years, residents in urban settlements in Czech Republic, Poland, Russia and Lithuania, randomly selected from population registers. The baseline survey in 2002-2005 included 36,106 persons of whom 24,993 met the inclusion criteria. Cox proportional hazards models were used to estimate the hazard ratios of mortality over 11-16 years of follow-up for mild, moderate, moderate-severe and very severe lung function impairment categories.

RESULTS

After adjusting for covariates, mild (hazard ratio (HR): 1.25; 95% CI 1.15‒1.37) to severe (HR: 3.35; 95% CI 2.62‒4.27) reduction in FEV1 was associated with an increased risk of death according to degree of lung impairment, compared to people with normal lung function. The association was only slightly attenuated but remained significant after exclusion of smokers and participants with previous history of respiratory diseases. The HRs varied between countries but not statistically significant; the highest excess risk among persons with more severe impairment was seen in Poland (HR: 4.28, 95% CI 2.14‒8.56) and Lithuania (HR: 4.07, 95% CI 2.21‒7.50).

CONCLUSIONS

Reduced FEV1 is an independent predictor of all-cause mortality, with risk increasing with the degree of lung function impairment and some country-specific variation between the cohorts.

Use of Dynamic Chest Radiography to Assess Treatment of Pulmonary Exacerbations in Cystic Fibrosis

Background Although spirometry is an important marker in the management of pulmonary exacerbations in cystic fibrosis (CF), it is a forced maneuver and can generate aerosol. Therefore, it may be difficult to perform in some individuals. Dynamic chest radiography (DCR) provides real-time information regarding pulmonary dynamics alongside fluoroscopic-style thoracic imaging. Purpose To assess the effect of pulmonary exacerbation treatment by using both spirometry and DCR and assess the clinical utility of DCR in participants with CF experiencing pulmonary exacerbations. Materials and Methods In this prospective, observational, single-center pilot study, spirometry and DCR were performed before and after treatment of pulmonary exacerbations in participants with CF between December 2019 and August 2020. Spirometry measured forced expiratory volume in 1 second (FEV₁) and forced vital capacity. DCR helped to measure projected lung area (PLA), hemidiaphragm midpoint position, and speed during tidal and deep breathing. Data were analyzed by using the paired t test or Wilcoxon signed-rank test. Correlation was assessed by using the Spearman rank correlation coefficient. Results Twenty participants with CF (mean age, 25 years ± 7 [standard deviation]; 14 women) were evaluated. Spirometry showed that percentage predicted FEV₁ improved from a median of 44% (interquartile range [IQR], 17%) before treatment to 55% (IQR, 16%) after treatment (P = .004). DCR showed improvement in median deep breathing excursion for left and right hemidiaphragms (from 18 [IQR, 11] to 25 [IQR, 16] mm [P = .03] and from 13 [IQR, 6] to 19 [IQR, 14] mm [P = .03], respectively) and in median expiratory speed following deep breathing for left and right hemidiaphragms (from 7 [IQR, 2] to 11 [IQR, 5] mm/sec [P = .004] and 6 [IQR, 3] to 9 [IQR, 6] mm/sec [P = .004], respectively). PLA rate of change during full expiration and change in PLA during tidal breathing improved (from a mean of 42 cm²/sec ± 16 to 56 cm²/sec ± 24 [P = .03] and from a mean of 29 cm² ± 14 to 35 cm² ± 10 [P = .03], respectively). Conclusion Dynamic chest radiography demonstrated improvement in diaphragm speed and range of chest wall movement during respiration aftere treatment for pulmonary exacerbations in cystic fibrosis and showed potential as a tool to investigate the effect of pulmonary exacerbations on lung mechanics. Clinical trials registration no. NCT01234567 Published under a CC BY 4.0 license. Online supplemental material is available for this article.

Volatile compounds in human breath: critical review and meta-analysis

Volatile compounds contained in human breath reflect the inner workings of the body. A large number of studies have been published that link individual components of breath to disease, but diagnostic applications remain limited, in part due to inconsistent and conflicting identification of breath biomarkers. New approaches are therefore required to identify effective biomarker targets. Here, volatile organic compounds have been identified in the literature from four metabolically and physiologically distinct diseases and grouped into chemical functional groups (e.g. - methylated hydrocarbons or aldehydes; based on known metabolic and enzymatic pathways) to support biomarker discovery and provide new insight on existing data. Using this functional grouping approach, principal component analysis doubled explanatory capacity from 19.1% to 38% relative to single individual compound approaches. Random forest and linear discriminant analysis reveal 93% classification accuracy for cancer. This review and meta-analysis provides insight for future research design by identifying volatile functional groups associated with disease. By incorporating our understanding of the complexities of the human body, along with accounting for variability in methodological and analytical approaches, this work demonstrates that a suite of targeted, functional volatile biomarkers, rather than individual biomarker compounds, will improve accuracy and success in diagnostic research and application.

"You're on mute!" Does pediatric CF home spirometry require physiologist supervision?

INTRODUCTION

The coronavirus disease 2019 (COVID-19) pandemic has accelerated the move towards home spirometry monitoring, including in children. The aim of this study is to determine whether the remote supervision of spirometry by a physiologist improves the technical quality and failure rate of the maneuvers.

METHOD

Children with cystic fibrosis who had been provided with NuvoAir home spirometers were randomly allocated to either supervised or unsupervised home spirometry following a detailed training session. Home spirometry was performed every 2 weeks for 12 weeks. Tests were assigned a quality factor (QF) using our laboratory grading system as per American Thoracic Society/European Respiratory Society standards, with tests marked from A to D, or Fail. In our laboratory, we aim for QF A in all spirometry tests, but report results of QF B or C with a cautionary note. QF A was, therefore, the primary outcome, and QF A-C, the secondary outcome.

RESULTS

Sixty-one patients were enrolled; 166 measurements were obtained in the supervised group, and 153 in the unsupervised group. Significantly more measurements achieved QF A in the supervised compared to unsupervised group (89% vs. 74%; p = <0.001), while proportions reaching Grade A-C were similar (99% vs. 95%; p = 0.1). All significant declines in spirometry results had a clinical rather than technical reason. Family/patient feedback for both arms was very positive.

CONCLUSION

These results suggest that home spirometry in children should ideally be remotely supervised by a physiologist, but acceptable results can be obtained if resources do not allow this, provided that training is delivered and results monitored according to our protocol.

Small Airways Response to Bronchodilators in Adults with Asthma or COPD: A Systematic Review

BACKGROUND

Bronchodilator responsiveness (BDR) is commonly used in the diagnosis of lung disease. Although small airways dysfunction is a feature of asthma and COPD, physiological tests of small airways are not included in guidelines for BDR testing. This systematic review assessed the current evidence of BDR using small airways function in asthma and COPD.

METHODS

The systematic review used standard methodology with the protocol prospectively registered on PROSPERO (CRD42020164140). Electronic medical databases (EMBASE and Medline) were searched using related keywords. Abstracts and full texts were screened independently by two reviewers. Studies that reported the change of physiological small airways function and FEV₁ were included in the review. The revised Cochrane risk of bias tool for RCT and NIH quality assessment tool for cohort and cross-sectional studies were used to evaluate the studies.

RESULTS

A total of 934 articles were identified, with 12 meeting the inclusion criteria. Ten studies included asthma patients, 1 study included COPD patients and 1 study included both asthma and COPD. A total of 1104 participants were included, of whom 941 were asthmatic, 64 had COPD and 109 were healthy controls. Studies were heterogeneous in design including the device, dose and time intervals for BDR assessment. A small airway BDR was seen for most tests in asthma and COPD, including oscillometry (R5-20, reactance (X5), area of reactance (AX) and resonant frequency (Fres)) and Maximal Mid Expiratory Flow.

CONCLUSION

There is a measurable BDR in the small airways. However, with no consensus on how to assess BDR, studies were heterogeneous. Further research is needed to inform how BDR should be assessed, its clinical impact and place in routine clinical practice.

ARTP statement on cardiopulmonary exercise testing 2021

Cardiopulmonary exercise testing (CPET) has become an invaluable tool in healthcare, improving the diagnosis of disease and the quality, efficacy, assessment and safety of treatment across a range of pathologies. CPET's superior ability to measure the global exercise response of the respiratory, cardiovascular and skeletal muscle systems simultaneously in a time and cost-efficient manner has led to the application of CPET in a range of settings from diagnosis of disease to preoperative assessment. The Association for Respiratory Technology and Physiology Statement on Cardiopulmonary Exercise Testing 2021 provides the practitioner and scientist with an outstanding resource to support and enhance practice, from equipment to testing to leadership, helping them deliver a quality assured service for the benefit of all patient groups.

There is No Fast Track to Identify Fast Decliners in Alpha-1 Antitrypsin Deficiency by Spirometry: A Longitudinal Study of Repeated Measurements

Background

It is known that lung function decline in Alpha-1 Antitrypsin Deficiency (AATD) varies. Those with a rapid decline are at highest risk of poorer outcomes but may benefit most from targeted treatments including augmentation therapy. Current evidence suggests rapid decliners can be identified after 3 years of serial follow-up. It would be advantageous to identify these patients over a shorter time period, especially in mild disease.

Methods

Post-bronchodilator spirometry was performed every 6 months for a total of 18 months (4 measurements) by PiZZ AATD patients (ex- or never-smokers) either without spirometric COPD or with mild COPD. Where possible, retrospective spirometry data were included. Decline was assessed using 2 (baseline and 6 month) or four measurements (including baseline, 6, 12 and 18 months) and compared to retrospective decline rates using annual measurements over 3 years.

Results

Seventy-two PiZZ AATD patients were included, with 27 having at least three years of retrospective, annual spirometry. 18-month progression obtained by linear regression showed variable degrees of change with 29 showing no decline, 8 showing slow decline and 35 showing rapid decline. Bland-Altman plots showed that there was no overall agreement between predicted rate of decline using data obtained over 6 months and that obtained over 18 months. Furthermore, there was no agreement between rate of decline from either 6 or 18 months’ data when compared to data collected over 3 years. The positive predictive value for rapid decline with 18 months of data compared to 3 years was only 50.0%.

Conclusion

This study suggests serial lung function over 18 months cannot identify AATD patients who have rapidly declining lung function. There is an urgent need for different biomarkers to help identify these patients at the earliest opportunity.