Standardisation of the measurement of lung volumes

[The forced oscillation technique in the functional evaluation of COPD dyspnea]

INTRODUCTION

The goal of the present study is to assess the relationship between functional respiratory parameters measured by the forced oscillation technique (FOT) in COPD patients and (1) dyspnea; (2) inspiratory capacity (IC), along with the variations occurring subsequent to bronchodilation.

METHODS

This cross-sectional study analyzed 40 stable COPD patients. Dyspnea was assessed by means of the San Diego Shortness of Breath Questionnaire. Forced oscillations were measured before and after bronchodilation by means of routine pulmonary function tests (PFTs).

RESULTS

The reactance parameters measured by the FOT correlated with dyspnea (AX5: r=0.46; P=0.003) similarly to IC (r=-0.46; P=0.003). Changes in AX5 following bronchodilation led to a predicted 12% and 200mL improvement in IC, AX5 (area under the ROC curve=0.85, P<0.001).

CONCLUSIONS

Forced oscillation technique (FOT) appears to be an interesting complement to routine PFTs in COPD assessment. Reactance parameters are correlated with dyspnea and their response to bronchodilators is a predictor of significantly improved inspiratory capacity (IC). All in all, FOT may be considered as a functional test with regard to pulmonary hyperinflation, a critical determinant of dyspnea.

Leveraging Therapy-Specific Polygenic Risk Scores to Predict Restrictive Lung Defects in Childhood Cancer Survivors

Therapy-related pulmonary complications are among the leading causes of morbidity among long-term survivors of childhood cancer. Restrictive ventilatory defects (RVD) are prevalent, with risks increasing after exposures to chest radiotherapy and radiomimetic chemotherapies. Using whole-genome sequencing data from 1,728 childhood cancer survivors in the St. Jude Lifetime Cohort Study, we developed and validated a composite RVD risk prediction model that integrates clinical profiles and polygenic risk scores (PRS), including both published lung phenotype PRSs and a novel survivor-specific pharmaco/radiogenomic PRS (surPRS) for RVD risk reflecting gene-by-treatment (GxT) interaction effects. Overall, this new therapy-specific polygenic risk prediction model showed multiple indicators for superior discriminatory accuracy in an independent data set. The surPRS was significantly associated with RVD risk in both training (OR = 1.60, P = 3.7 × 10-10) and validation (OR = 1.44, P = 8.5 × 10-4) data sets. The composite model featuring the surPRS showed the best discriminatory accuracy (AUC = 0.81; 95% CI, 0.76-0.87), a significant improvement (P = 9.0 × 10-3) over clinical risk scores only (AUC = 0.78; 95% CI: 0.72-0.83). The odds of RVD in survivors in the highest quintile of composite model-predicted risk was ∼20-fold higher than those with median predicted risk or less (OR = 20.01, P = 2.2 × 10-16), exceeding the comparable estimate considering nongenetic risk factors only (OR = 9.20, P = 7.4 × 10-11). Inclusion of genetic predictors also selectively improved risk stratification for pulmonary complications across at-risk primary cancer diagnoses (AUCclinical = 0.72; AUCcomposite = 0.80, P = 0.012). Overall, this PRS approach that leverages GxT interaction effects supports late effects risk prediction among childhood cancer survivors.

SIGNIFICANCE

This study develops a therapy-specific polygenic risk prediction model to more precisely identify childhood cancer survivors at high risk for pulmonary complications, which could help improve risk stratification for other late effects.

Physiological Predictors of Morbidity and Mortality in COPD: The Relative Importance of Reduced Inspiratory Capacity and Inspiratory Muscle Strength

Low resting inspiratory capacity (IC) and low maximal inspiratory pressure (MIP) have previously been linked to exertional dyspnea, exercise limitation and poor survival in chronic obstructive pulmonary disease (COPD). The interaction and relative contributions of these two related variables to important clinical outcomes are unknown. The objective of the current study was to examine the interaction between resting IC and MIP (both % predicted), exertional dyspnea, exercise capacity and long-term survival in patients with COPD. Two hundred and eighty-five patients with mild to advanced COPD completed standard lung function testing and a cycle cardiopulmonary exercise test. Multiple regression determined predictors of the exertional dyspnea-ventilation slope and peak oxygen uptake (V̇O_2peak). Cox regression determined predictors of 10-year mortality. IC was associated with the dyspnea-ventilation slope (standardized β=-0.44, p<0.001), while MIP was excluded from the regression model (p=0.713). IC and MIP were included in the final model to predict V̇O_2peak. However, the standardized β was greater for IC (0.49) than MIP (0.22). After adjusting for age, sex, body mass index, cardiovascular risk, airflow obstruction and diffusing capacity, resting IC was independently associated with 10-year all-cause mortality (hazard ratio=1.25, confidence interval_5-95%=1.16-1.34, p<0.001), while MIP was excluded from the final model (all p=0.829). Low resting IC was consistently linked to heightened dyspnea intensity, low V̇O_2peak and worse survival in COPD even after accounting for airway obstruction, inspiratory muscle strength, and diffusing capacity. These results support the use of resting IC as an important physiological biomarker closely linked to key clinical outcomes in COPD.

Model-based Bayesian inference of the ventilation distribution in patients with cystic fibrosis from multiple breath washout, with comparison to ventilation MRI

BACKGROUND

Indices of ventilation heterogeneity (VH) from multiple breath washout (MBW) have been shown to correlate well with VH indices derived from hyperpolarised gas ventilation MRI. Here we report the prediction of ventilation distributions from MBW data using a mathematical model, and the comparison of these predictions with imaging data.

METHODS

We developed computer simulations of the ventilation distribution in the lungs to model MBW measurement with 3 parameters: σ_V, determining the extent of VH; V₀, the lung volume; and V_D, the dead-space volume. These were inferred for each individual from supine MBW data recorded from 25 patients with cystic fibrosis (CF) using approximate Bayesian computation. The fitted models were used to predict the distribution of gas imaged by ³He ventilation MRI measurements collected from the same visit.

RESULTS

The MRI indices measured (I_1/3, the fraction of pixels below one-third of the mean intensity and I_CV, the coefficient of variation of pixel intensity) correlated strongly with those predicted by the MBW model fits (r=0.93,0.88 respectively). There was also good agreement between predicted and measured MRI indices (mean bias ± limits of agreement: I_1/3:-0.003±0.118 and I_CV:-0.004±0.298). Fitted model parameters were robust to truncation of MBW data.

CONCLUSION

We have shown that the ventilation distribution in the lung can be inferred from an MBW signal, and verified this using ventilation MRI. The Bayesian method employed extracts this information with fewer breath cycles than required for LCI, reducing acquisition time required, and gives uncertainty bounds, which are important for clinical decision making.

Dual-energy CT lung perfusion in systemic sclerosis: preliminary experience in 101 patients

OBJECTIVES

To investigate lung perfusion in systemic sclerosis (SSc).

METHODS

The study population included 101 patients who underwent dual-energy CT (DECT) in the follow-up of SSc with pulmonary function tests obtained within 2 months. Fifteen patients had right heart catheterization-proven PH.

RESULTS

Thirty-seven patients had no SSc-related lung involvement (Group A), 56 patients had SSc-related interstitial lung disease (Group B) of variable extent (Group B mild: ≤ 10% of lung parenchyma involved: n = 17; Group B moderate: between 11 and 50%: n = 31; Group B severe: > 50%: n = 8), and 8 patients had PVOD/PCH (Group C). Lung perfusion was abnormal in 8 patients in Group A (21.6%), 14 patients in Group B (25%), and 7 patients in Group C (87.5%). In Group A and Group B mild (n = 54), (a) patients with abnormal lung perfusion (n = 14; 26%) had a higher proportion of NYHA III/IV scores of dyspnea (7 [50%] vs 7 [17.5%]; p = 0.031) and a shorter mean walking distance at the 6MWT (397.0 [291.0; 466.0] vs 495.0 [381.0; 549.0]; p = 0.042) but no evidence of difference in the DLCO% predicted (61.0 [53.0; 67.0] vs 68.0 [61.0; 78.0]; p = 0.055) when compared to patients with normal lung perfusion (n = 40; 74%); (b) a negative correlation was found between the iodine concentration in both lungs and the DLCO% predicted but it did not reach statistical significance (r = -0.27; p = 0.059) and no correlation was found with the PAPs (r = 0.16; p = 0.29) and walking distance during the 6MWT (r = -0.029; p = 0.84).

CONCLUSIONS

DECT lung perfusion provides complementary information to standard HRCT scans, depicting perfusion changes in SSc patients with normal or minimally infiltrated lung parenchyma.

KEY POINTS

• In a retrospective observational study of 101 consecutive patients with SSc, dual-energy CT pulmonary angiography was obtained to evaluate lung perfusion. • Lung perfusion was abnormal in 14 out of 54 patients (26%) with no or mild SSc-related lung infiltration. • Patients with abnormal perfusion and no or mild SSc-related lung infiltration had more severe scores of dyspnea and shorter walking distance than patients with similar lung findings and normal perfusion, suggesting the presence of small vessel vasculopathy.

Exertional dyspnoea in patients with mild-to-severe chronic obstructive pulmonary disease (COPD): Neuromechanical mechanisms

KEY POINTS

Dyspnoea during exercise is a common and troublesome symptom reported by patients with chronic obstructive pulmonary disease (COPD) and is linked to an elevated inspiratory neural drive (IND). The precise mechanisms of elevated IND and dyspnoea across the continuum of airflow obstruction severity in COPD remains unclear. The present study sought to determine the mechanisms of elevated IND [by diaphragm EMG, EMGdi (%max)] and dyspnoea during cardiopulmonary exercise testing (CPET) across the continuum of COPD severity. There was a strong association between increasing dyspnoea intensity and EMGdi (%max) during CPET across the COPD continuum despite significant heterogeneity in underlying pulmonary gas exchange and respiratory mechanical impairments. Critical inspiratory constraints occurred at progressively lower ventilation during exercise with worsening severity of COPD. This was associated with the progressively lower resting inspiratory capacity with worsening disease severity. Earlier critical inspiratory constraint was associated with earlier neuromechanical dissociation and greater likelihood of reporting the sensation of 'unsatisfied inspiration'.

ABSTRACT

In patients with COPD, exertional dyspnoea generally arises when there is imbalance between ventilatory demand and capacity, but the neurophysiological mechanisms are unclear. We therefore determined if disparity between elevated inspiratory neural drive (IND) and tidal volume (V_T ) responses (neuromechanical dissociation) impacted dyspnoea intensity and quality during exercise, across the COPD severity spectrum. In this two-centre, cross-sectional observational study, 89 participants with COPD divided into tertiles of FEV₁ %predicted (Tertile 1 = FEV_1 =  87 ± 9%, Tertile 2 = 60 ± 9%, Tertile 3 = 32 ± 8%) and 18 non-smoking controls, completed a symptom-limited cardiopulmonary exercise tests (CPET) with measurement of IND by diaphragm electromyography [EMGdi (%max)]. The association between increasing dyspnoea intensity and EMGdi (%max) during CPET was strong (r = 0.730, P < 0.001) and not different between the four groups who showed marked heterogeneity in pulmonary gas exchange and mechanical abnormalities. Significant inspiratory constraints (tidal volume/inspiratory capacity (V_T /IC) ≥ 70%) and onset of neuromechanical dissociation (EMGdi (%max):V_T /IC > 0.75) occurred at progressively lower V̇_E from Control to Tertile 3. Lower resting IC meant earlier onset of neuromechanical dissociation, heightened dyspnoea intensity and greater propensity (93% in Tertile 3) to select qualitative descriptors of 'unsatisfied inspiration'. We concluded that, regardless of marked variation in mechanical and pulmonary gas exchange abnormalities in our study sample, exertional dyspnoea intensity was linked to the magnitude of EMGdi (%max). Moreover, onset of critical inspiratory constraints and attendant neuromechanical dissociation amplified dyspnoea intensity at higher exercise intensities. Simple measurements of IC and breathing pattern during CPET provide useful insights into mechanisms of dyspnoea and exercise intolerance in individuals with COPD. Abstract figure legend As chronic obstructive pulmonary disease severity increases, worsening gas exchange and respiratory mechanical impairment causes increased afferent receptor stimulation, increasing inspiratory neural drive at a given ventilation. The widening disparity between progressively greater inspiratory neural drive and reduced ventilatory output causes, 'neuromechanical dissociation'. This is strongly associated with a rapid increase in the intensity of dyspnea during exercise, and the onset of the sensation of 'unsatisfied inspiration'. This article is protected by copyright. All rights reserved.

Small Airways Dysfunction is Associated with Increased Exacerbations in Patients with Asthma

There is poor understanding of why some patients with asthma experience recurrent exacerbations despite high levels of treatment. We compared measurements of peripheral ventilation heterogeneity and respiratory system mechanics in participants with asthma who were differentiated according to exacerbation history, to ascertain whether peripheral airway dysfunction was related to exacerbations. Three asthmatic groups: "Stable" (no exacerbations for >12 months, n=18), "Exacerbation-prone" (≥1 exacerbation requiring systemic corticosteroids within the last 12 months, but stable for ≥1-month, n=9) and "Treated-exacerbation" (exacerbation requiring systemic corticosteroids within the last 1 month, n=12) were studied. All participants were current non-smokers with <10pack/years smoking history. Spirometry, static lung volumes, ventilation heterogeneity from multi-breath nitrogen washout (MBW) and respiratory system mechanics from oscillometry were measured. The Exacerbation-prone group compared to the Stable group had slightly worse spirometry (FEV₁ Z-score -3.58(1.13) vs -2.32(1.06), p=0.03), however acinar ventilation heterogeneity (S_acin Z-score 7.43(8.59) vs 3.63(3.88), p=0.006) and respiratory system reactance (X_rs cmH₂O.s.L^-1 -2.74(3.82) vs -1.32(1.94), p=0.01) were much worse in this group. The Treated-exacerbation group had worse spirometry but similar small airway function, compared with the Stable group. Patients with asthma who exacerbate have worse small airway function as evidenced by increases in S_acin measured by MBW and delta X_rs from oscillometry, both markers of small airway dysfunction, compared with those that do not.

Single dose of budesonide/formoterol turbuhaler compared to salbutamol pMDI for speed of bronchodilator onset in asthma: a randomised cross-over trial

OBJECTIVE

To compare bronchodilator response after to salbutamol and budesonide/formoterol in adults with stable asthma.

METHODS

A double-blind, cross-over, single-centre, placebo-controlled, non-inferiority trial. Adults with stable asthma were randomised to different orders of two treatment regimens: two actuations of placebo via MDI and one actuation of budesonide/formoterol 200/6 µg via turbuhaler; and one actuation of placebo turbuhaler and two actuations of salbutamol 100 µg via MDI. The primary outcome measure was FEV1 after 2 min. Secondary outcome measures included FEV1, mBorg Dyspnoea Scale score and visual analogue score for breathlessness over 30 min.

RESULTS

Forty-nine of 50 potential participants were randomised. One participant withdrew following the first intervention visit and another could not be randomised due to COVID-19 restrictions. The mean (SD) change from baseline FEV1 2 min after treatment administration for budesonide/formoterol and salbutamol was 0.08 (0.14) L, n=49, and 0.17 (0.18) L, n=48, respectively, mean (95% CI) paired difference of -0.097 L (-0.147 to -0.047), p=0.07, against a non-inferiority bound of -0.06 L. In the secondary analysis, FEV1 over 30 min was lower for budesonide/formoterol compared with salbutamol, difference (95% CI): -0.10 (-0.12 to -0.08) L, p<0.001. There were no differences in Visual Analogue Scale score or mBorg Dyspnoea Scale score between treatments.

CONCLUSION

The results do not support the primary hypothesis of non-inferiority at the boundary of -0.06 L for the difference between budesonide/formoterol 200/6 µg compared with salbutamol 200 µg for FEV1 at 2 min, and could be consistent with inferiority with a p value of 0.07. For the secondary analysis of FEV1 measurements over time, the FEV1 was higher with salbutamol.

TRIAL REGISTRATION NUMBER

Australian and New Zealand Clinical Trials Registry (ACTRN 12619001387112).

Air pollution enhance the progression of restrictive lung function impairment and diffusion capacity reduction: an elderly cohort study

BACKGROUND

Some evidences have shown the association between air pollution exposure and the development of interstitial lung diseases. However, the effect of air pollution on the progression of restrictive ventilatory impairment and diffusion capacity reduction is unknown. This study aimed to evaluate the effects of long-term exposure to ambient air pollution on the change rates of total lung capacity, residual volume, and diffusion capacity among the elderly.

METHODS

From 2016 to 2018, single-breath helium dilution with the diffusion capacity of carbon monoxide was performed once per year on 543 elderly individuals. Monthly concentrations of ambient fine particulate matters (PM_2.5) and nitric dioxide (NO₂) at the individual residential address were estimated using a hybrid Kriging/Land-use regression model. Linear mixed models were used to evaluate the association between long-term (12 months) exposure to air pollution and lung function with adjustment for potential covariates, including basic characteristics, indoor air pollution (second-hand smoke, cooking fume, and incense burning), physician diagnosed diseases (asthma and chronic airway diseases), dusty job history, and short-term (lag one month) air pollution exposure.

RESULTS

An interquartile range (5.37 ppb) increase in long-term exposure to NO₂ was associated with an additional rate of decline in total lung volume (- 1.8% per year, 95% CI: - 2.8 to - 0.9%), residual volume (- 3.3% per year, 95% CI: - 5.0 to - 1.6%), ratio of residual volume to total lung volume (- 1.6% per year, 95% CI: - 2.6 to - 0.5%), and diffusion capacity (- 1.1% per year, 95% CI: - 2.0 to - 0.2%). There is no effect on the transfer factor (ratio of diffusion capacity to alveolar volume). The effect of NO₂ remained robust after adjustment for PM_2.5 exposure.

CONCLUSIONS

Long-term exposure to ambient NO₂ is associated with an accelerated decline in static lung volume and diffusion capacity in the elderly. NO₂ related air pollution may be a risk factor for restrictive lung disorders.

Sex Differences in Diaphragm Voluntary Activation after Exercise

INTRODUCTION

The female diaphragm develops less fatigue after high-intensity exercise compared with males. Diaphragm fatigability is typically defined as a decrease in transdiaphragmatic twitch pressure (Pdi,TW) and represents the contractile function of the muscle. However, it is unclear whether this sex difference persists when examining changes in voluntary activation, which represents a neural mechanism contributing to fatigability.

PURPOSE

This study aimed to determine if high-intensity cycling results in a decrease in diaphragm voluntary activation (D-VA) and to explore if the decrease in D-VA is different between sexes.

METHODS

Twenty-five participants (15 females) completed a single bout of high-intensity constant load cycling. D-VA and Pdi,TW were measured before and after exercise using cervical magnetic stimulation of the phrenic nerves to assess diaphragm fatigability.

RESULTS

Participants were of similar aerobic fitness when expressed relative to predicted values (females: 114% ± 25% predicted, males: 111% ± 11% predicted; P = 0.769). Pdi,TW decreased relative to baseline to 85.2% ± 16.7% and 70.3% ± 12.4% baseline (P = 0.012) in females and males, respectively, immediately after exercise. D-VA also decreased in both females and males immediately after exercise. The decrease in D-VA was less in females compared with males (95.4% ± 4.9% baseline vs 87.4% ± 10.8% baseline, respectively; P = 0.018).

CONCLUSIONS

D-VA decreases after whole-body exercise in both females and males, although the magnitude of the decrease is not as large in females compared with males. The findings of this study suggest that the female diaphragm is more resistant to both contractile and neural mechanisms of fatigability after whole-body exercise.

ERS/ATS technical standard on interpretive strategies for routine lung function tests

BACKGROUND

Appropriate interpretation of pulmonary function tests (PFTs) involves the classification of observed values as within/outside the normal range based on a reference population of healthy individuals, integrating knowledge of physiological determinants of test results into functional classifications and integrating patterns with other clinical data to estimate prognosis. In 2005, the American Thoracic Society (ATS) and European Respiratory Society (ERS) jointly adopted technical standards for the interpretation of PFTs. We aimed to update the 2005 recommendations and incorporate evidence from recent literature to establish new standards for PFT interpretation.

METHODS

This technical standards document was developed by an international joint Task Force, appointed by the ERS/ATS with multidisciplinary expertise in conducting and interpreting PFTs and developing international standards. A comprehensive literature review was conducted and published evidence was reviewed.

RESULTS

Recommendations for the choice of reference equations and limits of normal of the healthy population to identify individuals with unusually low or high results are discussed. Interpretation strategies for bronchodilator responsiveness testing, limits of natural changes over time and severity are also updated. Interpretation of measurements made by spirometry, lung volumes and gas transfer are described as they relate to underlying pathophysiology with updated classification protocols of common impairments.

CONCLUSIONS

Interpretation of PFTs must be complemented with clinical expertise and consideration of the inherent biological variability of the test and the uncertainty of the test result to ensure appropriate interpretation of an individual's lung function measurements.

Sex differences in the ventilatory responses to exercise in mild-moderate obesity

NEW FINDINGS

What is the central question of the study? What are the sex differences in ventilatory responses during exercise in adults with obesity. What is the main finding and its importance? Tidal volume and expiratory flows are lower in females when compared with males at higher levels of ventilation despite small increases in end-expiratory lung volumes. Since dyspnea on exertion is a frequent complaint, particularly in females with obesity, careful attention should be paid to unpleasant respiratory symptoms and mechanical ventilatory constraints before prescribing exercise.

ABSTRACT

Obesity is associated with altered ventilatory responses, which may be exacerbated in females due to the functional consequences of sex-related morphological differences in the respiratory system. This study examined sex differences in ventilatory responses during exercise in adults with obesity. Healthy adults with obesity (n = 73; 48 females) underwent pulmonary function testing, underwater weighing, magnetic resonance imaging, a graded exercise test to exhaustion, and two constant work rate exercise tests; one at a fixed work rate (60W for females and 105W for males) and one at a relative intensity (50% of peak oxygen uptake, V̇O_2peak ). Metabolic, respiratory, and perceptual responses were assessed during exercise. Compared with males, females used a smaller proportion of their ventilatory capacity at peak exercise (69.13 ± 14.49 vs. 77.41 ± 17.06 % maximum voluntary ventilation, P = 0.0374). Females also utilized a smaller proportion of their forced vital capacity (FVC) at peak exercise (tidal volume: 48.51±9.29 vs. 54.12±10.43 %FVC, P = 0.0218). End-expiratory lung volumes were 2-4% higher in females compared with males during exercise (P<0.05), while end-inspiratory lung volumes were similar. Since the males were initiating inspiration from a lower lung volume, they experienced greater expiratory flow limitation during exercise. Ratings of perceived breathlessness during exercise were similar between females and males at comparable levels of ventilation. In summary, sex differences in the manifestations of obestity-related mechanical ventilatory constraints were observed. Since dyspnea on exertion is a common complaint in patients with obesity, particularly in females, exercise prescriptions should be tailored with the goal of minimizing unpleasant respiratory sensations. This article is protected by copyright. All rights reserved.

Differences in Pulmonary and Extra-Pulmonary Traits between Women and Men with Chronic Obstructive Pulmonary Disease

Background: Evidence suggests sex-related differences in chronic obstructive pulmonary disease (COPD). Whether these differences are reflected in the prevalence of treatable traits remains unknown. Methods: Two samples of patients referred to secondary (n = 530) or tertiary care (n = 2012) were analyzed. Men and women were matched for age, forced expiratory volume in 1 s and body mass index. Sex-related differences were tested using t-tests, Mann-Whitney U, or chi-square tests. Results: Frequent exacerbations (30.5 vs. 19.7%), high cardiovascular risk (88.1 vs. 66.2%) and activity-related severe dyspnea (50.9 vs. 34.8%) were more prevalent in women in secondary care (p < 0.05). Severe hyperinflation (43.0 vs. 25.4%), limited diffusing capacity (79.6 vs. 70.1%), impaired mobility (44.0 vs. 28.7%), frequent exacerbations (66.8 vs. 57.4%), frequent hospitalizations (47.5 vs. 41.6%), severe activity-related dyspnea (89.1 vs. 85.0%), symptoms of anxiety (56.3 vs. 42.0%) and depression (50.3 vs. 44.8%), and poor health status (79.9 vs. 71.0%) were more prevalent in women in tertiary care (p < 0.05). Severe inspiratory muscle weakness (14.6 vs. 8.2%) and impaired exercise capacity (69.1 vs. 59.6%) were more prevalent among men (p < 0.05) in tertiary care. Conclusions: Sex-related differences were found, with most traits more prevalent and severe among women. Care providers should be aware of these differences to adjust treatment.

Influence of respiratory loading on left-ventricular function in cervical spinal cord injury

KEY POINTS

Cervical spinal cord injury (C-SCI) alters both the cardiac and respiratory systems, however little is known as to how these systems interact following injury. Here, we manipulated inspiratory or expiratory intrathoracic pressure (ITP) to mechanistically test the role of the respiratory pump on circulatory function in highly-trained individuals with C-SCI and an able-bodied reference group. In individuals with C-SCI, greater ITP during expiratory loading caused dynamic hyperinflation that was associated with impaired left-ventricular filling. More negative ITP during inspiratory loading did not significantly alter left-ventricular volumes in either group. Interventions that prevent dynamic hyperinflation and/or enhance the ability to generate expiratory pressures may help preserve left-ventricular filling in individuals with C-SCI.

ABSTRACT

Cervical spinal cord injury (C-SCI) negatively impacts cardiac and respiratory function. As the heart and lungs are linked via the pulmonary circuit these systems are interdependent. Here, we utilized inspiratory and expiratory loading to assess whether augmenting the respiratory pump improves left-ventricular (LV) filling and output in individuals with motor-complete C-SCI. We hypothesized LV end-diastolic volume (LVEDV) would increase and decrease with inspiratory and expiratory loading, respectively. Participants (C-SCI: 7M/1F, 35±7 years; able-bodied: 7M/1F, 32±6 years) were assessed under five conditions during 45° head-up tilt; unloaded, inspiratory loading with -10 and -20cmH₂ O esophageal pressure (Pes) on inspiration, and expiratory loading with +10 and +20cmH₂ O Pes on expiration. An esophageal balloon catheter monitored Pes and LV structure and function were assessed by echocardiography. In C-SCI only, (1) +20cmH₂ O reduced LVEDV vs. unloaded (81±15 vs. 88±11 mL, p = 0.006); (2) heart rate was higher during +20cmH₂ O compared to unloaded (p = 0.001) and +10cmH₂ O (p = 0.002); (3) cardiac output was higher during +20cmH₂ O than unloaded (p = 0.002); and (4) end-expiratory lung volume was higher during +20cmH₂ O vs. unloaded (63±10 vs. 55±13% total lung capacity, p = 0.003) but was unaffected by inspiratory loading. In both groups, -10 and -20cmH₂ O had no significant effect on LVEDV. These findings suggest greater expiratory positive pressure acutely impairs LV filling in C-SCI, potentially via impaired venous return, mediastinal constraint and/or direct ventricular interaction subsequent to dynamic hyperinflation. Inspiratory loading did not significantly improve LV function in C-SCI and neither inspiratory nor expiratory loading affected cardiac function or lung volumes in able-bodied participants. Abstract figure legend Background: Cervical spinal cord injury (C-SCI) alters both the cardiac and respiratory systems. However, expiratory function is compromised to a greater extent than inspiratory function. Experimental set up: To examine how the cardiac and respiratory systems interact following C-SCI we manipulated inspiratory or expiratory intrathoracic pressure (ITP) to mechanistically test how changes in ITP and lung volumes influence cardiac function in highly-trained individuals with C-SCI and an able-bodied reference group. Participants were assessed under five conditions during 45° head-up tilt; unloaded, two inspiratory loading, and two expiratory loading conditions.

KEY FINDINGS

Following C-SCI, greater ITP during expiratory loading increased lung volumes and was associated with impaired left-ventricular filling. Interventions that prevent increases in lung volumes and/or enhance the ability to generate expiratory pressures may help preserve left-ventricular filling in individuals with C-SCI. A portion of this figure was created with biorender.com This article is protected by copyright. All rights reserved.

Forced Oscillation Measurements in Patients with Idiopathic Interstitial Pneumonia Subjected to Pulmonary Rehabilitation

(1) Background: Pulmonary rehabilitation (PR) plays a significant therapeutic role for patients with idiopathic interstitial pneumonia (IIP). The study assessed the impact of physical activity on lung function measured by forced oscillation technique (FOT). (2) Methods: The study involved 48 patients with IIP subjected to a 3-week inpatient PR. The control group included IIP patients (n = 44) on a 3-week interval without PR. All patients were assessed at baseline and after 3 weeks of PR by FOT, spirometry, plethysmography, grip strength measurement and the 6-minute walk test. (3) Results: There were no significant changes in FOT measurements in the PR group, except for reduced reactance at 11 Hz, observed in both groups (p < 0.05). Patients who completed PR significantly improved their 6-min walk distance (6MWD) and forced vital capacity (FVC). The change in 6MWD was better in patients with higher baseline reactance (p = 0.045). (4) Conclusions: Patients with IIP benefit from PR by an increased FVC and 6MWD; however, no improvement in FOT values was noticed. Slow disease progression was observed in the study and control groups, as measured by reduced reactance at 11 Hz. Patients with lower baseline reactance limitations achieve better 6MWD improvement.

Long-term clinical course and outcomes in patients with lymphangioleiomyomatosis

Background

Lymphangioleiomyomatosis (LAM) is a rare multisystemic disorder with various clinical manifestations. Despite the recognition of several prognostic factors, the long-term clinical course and prognosis of patients with LAM in the era of sirolimus therapy are not established.

Methods

The clinical data of 104 patients with LAM were retrospectively analyzed. Death or lung transplantation was defined as the primary outcome. Disease progression (DP) was defined as a 10% absolute decline in forced expiratory volume in one second (FEV₁).

Results

The mean age of all patients was 40.3 years. Over a median follow-up period of 7.1 years, of all patients, 6.7% died and 1.9% underwent lung transplantation, while of 92 patients with serial lung function data, 35.9% experienced DP. The 5-year and 10-year overall survival rates were 93.0% and 90.9%, respectively. The multivariable Cox analysis revealed that older age (hazard ratio [HR]: 1.136, P = 0.025), lower FEV₁ (HR: 0.956, P = 0.026) or diffusing capacity for carbon monoxide (HR: 0.914, P = 0.003), and shorter distance during the 6-min walk test (HR: 0.993, P = 0.020) were independent prognostic factors for mortality. A propensity score-matched comparative analysis performed between patients who received sirolimus therapy and those who did not, found no differences in survival, DP, complications, and lung function decline rate.

Conclusions

Over a follow-up period of approximately 7 years, one-tenth of all patients experienced death, while one-third experienced DP. Older age, lower lung function, and reduced exercise capacity were associated with a poor prognosis in patients with LAM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02079-6.

Body Composition-Specific Asthma Phenotypes: Clinical Implications

Background: Previous studies have indicated the limitations of body mass index for defining disease phenotypes. The description of asthma phenotypes based on body composition (BC) has not been largely reported. Objective: To identify and characterize phenotypes based on BC parameters in patients with asthma. Methods: A study with two prospective observational cohorts analyzing adult patients with stable asthma (n = 541 for training and n = 179 for validation) was conducted. A body composition analysis was performed for the included patients. A cluster analysis was conducted by applying a 2-step process with stepwise discriminant analysis. Logistic regression models were used to evaluate the association between identified phenotypes and asthma exacerbations (AEs). The same algorithm for cluster analysis in the independent validation set was used to perform an external validation. Results: Three clusters had significantly different characteristics associated with asthma outcomes. An external validation identified the similarity of the participants in training and the validation set. In the training set, cluster Training (T) 1 (29.4%) was “patients with undernutrition”, cluster T2 (18.9%) was “intermediate level of nutrition with psychological dysfunction”, and cluster T3 (51.8%) was “patients with good nutrition”. Cluster T3 had a decreased risk of moderate-to-severe and severe AEs in the following year compared with the other two clusters. The most important BC-specific factors contributing to being accurately assigned to one of these three clusters were skeletal muscle mass and visceral fat area. Conclusion: We defined three distinct clusters of asthma patients, which had distinct clinical features and asthma outcomes. Our data reinforced the importance of evaluating BC to determining nutritional status in clinical practice.

Dehydroepiandrosterone in fibrotic interstitial lung disease: a translational study

BACKGROUND

Dehydroepiandrosterone (DHEA) is a precursor sex hormone with antifibrotic properties. The aims of this study were to investigate antifibrotic mechanisms of DHEA, and to determine the relationship between DHEA-sulfate (DHEAS) plasma levels, disease severity and survival in patients with fibrotic interstitial lung diseases (ILDs).

METHODS

Human precision cut lung slices (PCLS) and normal human lung fibroblasts were treated with DHEA and/or transforming growth factor (TGF)-β1 before analysis of pro-fibrotic genes and signal proteins. Cell proliferation, cytotoxicity, cell cycle and glucose-6-phosphate dehydrogenase (G6PD) activity were assessed. DHEAS plasma levels were correlated with pulmonary function, the composite physiologic index (CPI), and time to death or lung transplantation in a derivation cohort of 31 men with idiopathic pulmonary fibrosis (IPF) and in an independent validation cohort of 238 men and women with fibrotic ILDs.

RESULTS

DHEA decreased the expression of pro-fibrotic markers in-vitro and ex-vivo. There was no cytotoxic effect for the applied concentrations, but DHEA interfered in proliferation by modulating the cell cycle through reduction of G6PD activity. In men with IPF (derivation cohort) DHEAS plasma levels in the lowest quartile were associated with poor lung function and higher CPI (adjusted OR 1.15 [95% CI 1.03-1.38], p = 0.04), which was confirmed in the fibrotic ILD validation cohort (adjusted OR 1.03 [95% CI 1.00-1.06], p = 0.01). In both cohorts the risk of early mortality was higher in patients with low DHEAS levels, after accounting for potential confounding by age in men with IPF (HR 3.84, 95% CI 1.25-11.7, p = 0.02), and for age, sex, IPF diagnosis and prednisone treatment in men and women with fibrotic ILDs (HR 3.17, 95% CI 1.35-7.44, p = 0.008).

CONCLUSIONS

DHEA reduces lung fibrosis and cell proliferation by inducing cell cycle arrest and inhibition of G6PD activity. The association between low DHEAS levels and disease severity suggests a potential prognostic and therapeutic role of DHEAS in fibrotic ILD.

Quantitative CT Lung Imaging and Machine Learning Improves Prediction of Emergency Room Visits and Hospitalizations in COPD

RATIONALE

Predicting increased risk of future healthcare utilization in chronic obstructive pulmonary disease (COPD) patients is an important goal for improving patient management.

OBJECTIVE

Our objective was to determine the importance of computed tomography (CT) lung imaging measurements relative to other demographic and clinical measurements for predicting future health services use with machine learning in COPD.

MATERIALS AND METHODS

In this retrospective study, lung function measurements and chest CT images were acquired from Canadian Cohort of Obstructive Lung Disease study participants from 2010 to 2017 (https://clinicaltrials.gov, NCT00920348). Up to two follow-up visits (1.5- and 3-year follow-up) were performed and participants were asked for details related to healthcare utilization. Healthcare utilization was defined as any COPD hospitalization or emergency room visit due to respiratory problems in the 12 months prior to the follow-up visits. CT analysis was performed (VIDA Diagnostics Inc.); a total of 108 CT quantitative emphysema, airway and vascular measurements were investigated. A hybrid feature selection method with support vector machine classifier was used to predict healthcare utilization. Performance was determined using accuracy, F1-measure and area under the receiver operating characteristic curve (AUC) and Matthews's correlation coefficient (MC).

RESULTS

Of the 527 COPD participants evaluated, 179 (35%) used healthcare services at follow-up. There were no significant differences between the participants with or without healthcare utilization at follow-up for age (p = 0.50), sex (p = 0.44), BMI (p = 0.05) or pack-years (p = 0.76). The accuracy for predicting subsequent healthcare utilization was 80% ± 3% (F1-measure = 74%, AUC = 0.80, MC = 0.6) when all measurements were considered, 76% ± 6% (F1-measure = 72%, AUC = 0.77, MC = 0.55) for CT measurements alone and 65% ± 5% (F1-measure = 60%, AUC = 0.67, MC = 0.34) for demographic and lung function measurements alone.

CONCLUSION

The combination of CT lung imaging and conventional measurements leads to greater prediction accuracy of subsequent health services use than conventional measurements alone, and may provide needed prognostic information for patients suffering from COPD.

Digital quantification of p16-positive foci in fibrotic interstitial lung disease is associated with a phenotype of idiopathic pulmonary fibrosis with reduced survival

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is associated with increased expression of cyclin-dependent kinase inhibitors such as p16 and p21, and subsequent induction of cell cycle arrest, cellular senescence, and pro-fibrotic gene expression. We sought to link p16-expression with a diagnosis of IPF or other fibrotic interstitial lung diseases (ILDs), radiographic pattern, senescent foci-specific gene expression, antifibrotic therapy response, and lung transplant (LTx)-free survival.

METHODS

Eighty-six cases of fibrosing ILD were identified with surgical lung biopsy. Immunohistochemistry for p16 was performed on sections with the most active fibrosis. p16-positive foci (loose collection of p16-positive fibroblasts with overlying p16-positive epithelium) were identified on digital slides and quantified. Cases were scored as p16-low (≤ 2.1 foci per 100 mm²) or p16-high (> 2.1 foci per 100 mm²). Twenty-four areas including senescent foci, fibrotic and normal areas were characterized using in situ RNA expression analysis with digital spatial profiling (DSP) in selected cases.

RESULTS

The presence of p16-positive foci was specific for the diagnosis of IPF, where 50% of cases expressed any level of p16 and 26% were p16-high. There was no relationship between radiographic pattern and p16 expression. However, there was increased expression of cyclin-dependent kinase inhibitors, collagens and matrix remodeling genes within p16-positive foci, and cases with high p16 expression had shorter LTx-free survival. On the other hand, antifibrotic therapy was significantly protective. DSP demonstrated that fibroblastic foci exhibit transcriptional features clearly distinct from that of normal-looking and even fibrotic areas.

CONCLUSIONS

We demonstrated the potential clinical applicability of a standardized quantification of p16-positive fibroblastic foci. This method identifies an IPF phenotype associated with foci-specific upregulation of senescence-associated and matrix remodeling gene expression. While these patients have reduced LTx-free survival, good response to antifibrotic therapies was observed in those who were treated.

Pleuroparenchymal fibroelastosis in rheumatoid arthritis-associated interstitial lung disease

Background

Pleuroparenchymal fibroelastosis (PPFE) is a rare interstitial lung disease (ILD) featuring dense fibrosis of the visceral pleura and subpleural parenchyma, mostly in the upper lobes. PPFE can present in other ILDs, including rheumatoid arthritis-associated ILD (RA-ILD). The aim of this retrospective study was to investigate the prevalence and clinical implications of coexistent PPFE in RA-ILD.

Methods

Overall, 477 patients with RA-ILD were recruited from two cohorts; their clinical data and HRCT images were analysed. The criteria for diagnosing PPFE were (1) pleural thickening with bilateral subpleural dense fibrosis in the upper lobes, (2) evidence of disease progression, and (3) absence of other identifiable aetiologies.

Results

The median follow-up duration was 3.3 years. The mean age of the patients was 63.4 years, and 60.0% were women. PPFE was identified in 31 patients (6.5%). The PPFE group showed significantly lower body mass index and forced vital capacity (FVC) and more frequent usual interstitial pneumonia (UIP)-like pattern on HRCT than no-PPFE group. The risk factors for all-cause mortality were older age, lower FVC, and the presence of UIP-like pattern on HRCT; PPFE was not significantly associated with mortality in both all patients and a subgroup with a UIP-like pattern. The presence of PPFE was associated with a significantly increased risk of pneumothorax and greater decline in diffusing capacity.

Conclusions

PPFE was not rare in patients with RA-ILD and was significantly associated with an increased risk of pneumothorax and greater lung function decline, though we found no significant association with mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02064-z.

Longitudinal Impact of Sputum Inflammatory Phenotypes on Small Airway Dysfunction and Disease Outcomes in Asthma

BACKGROUND

Little is known about the relationship between airway inflammatory phenotypes and some important asthma features such as small airway dysfunction (SAD).

OBJECTIVE

To describe the longitudinal impact of airway inflammatory phenotypes on SAD and asthma outcomes.

METHODS

We measured eosinophil and neutrophil counts in induced sputum at baseline and 1 year later to stratify 197 adult patients with asthma into 4 inflammatory phenotypes. We conducted a comprehensive assessment of lung function using spirometry, body plethysmography, impulse oscillometry, and inert gas single and multiple breath washouts. We compared lung function, asthma severity, exacerbation frequency, and symptom control between the phenotypes. We studied the longitudinal impact of persistent sputum inflammatory phenotypes and the change of sputum cell counts on lung function.

RESULTS

Patients were stratified into eosinophilic (23%, n = 45), neutrophilic (33%, n = 62), mixed granulocytic (22%, n = 43), and paucigranulocytic (24%, n = 47) phenotypes. Patients with eosinophilic and mixed granulocytic asthma had higher rates of airflow obstruction and severe exacerbation as well as poorer symptom control than patients with paucigranulocytic asthma. All SAD measures were worse in patients with eosinophilic and mixed asthma than in those with paucigranulocytic asthma (all P values <.05). Eosinophilic asthma also indicated worse distal airflow obstruction, increased ventilation inhomogeneity (all P values <.05), and higher tendency for severe exacerbation (P = .07) than neutrophilic asthma. Longitudinally, persistent mixed granulocytic asthma was associated with the worst follow-up measures of SAD compared with persistent neutrophilic, persistent paucigranulocytic, or nonpersistent asthma phenotypes. In patients with stable forced expiratory volume in 1 second (FEV1), the mean increase in small airway resistance (R5-20) was greater in patients with persistent mixed granulocytic asthma (+103%) than in patients with persistent neutrophilic (+26%), P = .040, or persistent paucigranulocytic asthma (-41%), P = .028. Multivariate models adjusted for confounders and treatment with inhaled or oral corticosteroids or antieosinophilic biologics indicated that the change of sputum eosinophil rather than neutrophil counts is an independent predictor for the longitudinal change in FEV1, forced expiratory flow at 25% to 75% of forced vital capacity, specific effective airway resistance, residual lung volume, and lung clearance index.

CONCLUSIONS

In asthma, airway eosinophilic inflammation is the main driver of lung function impairment and poor disease outcomes, which might also be aggravated by the coexistence of airway neutrophilia to confer a severe mixed granulocytic asthma phenotype. Persistent airway eosinophilia might be associated with dynamic SAD even in patients with stable FEV1.

The disconnect between visual assessment of air trapping and lung physiology for assessment of small airway disease in scleroderma-related interstitial lung disease: An observation from the Scleroderma Lung Study II Cohort

OBJECTIVE

To explore the presence of small airway disease (SAD) and emphysema in scleroderma-related interstitial lung disease (SSc-ILD) and to evaluate the physiologic and clinical correlates of SAD in SSc-ILD.

METHODS

Thoracic high-resolution computed tomography (HRCT) images obtained from the Scleroderma Lung Study II (SLSII) participants were reviewed by a group of thoracic radiologists. The presence of SAD was assessed by visual assessment for air trapping. HRCT scans were also evaluated for the presence of emphysema. The association of the presence of air trapping and emphysema with physiological measures of airway disease and clinical variables was evaluated.

RESULTS

A total of 155 baseline HRCT scans were reviewed. For assessment of air trapping, images needed to be adequate end-expiratory examinations, leaving 123 scans. Air trapping was seen in 13/123 (10.6%) of the SSc-ILD cohort and was independent of smoking history, asthma or the presence of gastroesophageal reflux. Air trapping on HRCT was not associated with physiologic evidence of SAD. We also identified 8/155 (5.2%) patients with emphysema on HRCT, which was independent of SAD and found mostly in prior smokers.

CONCLUSION

We report the first study of air trapping on standardized, high-quality HRCT images as a reflection of SAD in a relatively large, well characterized SSc-ILD cohort. The presence of SAD in non-smoking SSc-ILD patients supports that SSc may cause not only restrictive lung disease (SSc-ILD), but also, to a lesser extent, obstructive disease. Physiologic measures alone may be inadequate to detect airway disease in patients with SSc-ILD.

Safety and efficacy of transcatheter mitral valve repair in patients with COPD; results from real-world cohort

OBJECTIVE

To evaluate the safety and efficacy of transcatheter mitral valve repair (TMVR) in patients with chronic obstructive pulmonary disease (COPD).

BACKGROUND

Heart failure and COPD share many clinical features and commonly coexist. Data about the safety and efficacy of TMVR in patients with COPD is not conclusive.

METHODS

Three hundred and forty consecutive patients undergoing TMVR were retrospectively included. COPD diagnosis was based on pulmonary function tests (PFTs). Intra-hospital, 30-day- and 1-year outcomes were compared between both groups.

RESULTS

Eighty-two patients had COPD (24%). There was no difference in intra-hospital mortality between patients with and without COPD (both 5%, p = 0.95). Among patients who had a successful procedure and survived to discharge there was a trend toward more rehospitalization due to decompensated heart failure at 30-day follow-up in patients with COPD (12.9% vs. 6.8%, p = 0.08) with no difference in mortality. At median follow-up of 1 year, New York heart association (NYHA) category was comparable among both groups and there was no significant difference in rehospitalization (COPD: 29.9% vs. non-COPD: 34%, p = 0.5). There was a trend toward increased 1-year mortality in COPD patients (31.2% vs. 20.6%, p = 0.06). However, a composite endpoint of rehospitalization or death at 1 year did not differ between both groups (48% vs. 42.5%, p = 0.4). Regression analysis showed no correlation between COPD severity and worse TMVR outcomes.

CONCLUSIONS

COPD is highly prevalent among patients undergoing TMVR. However, TMVR seems to be safe and effective in COPD patients. COPD severity and PFT impairment alone should not be considered as a contraindication for TMVR.

Impact of the revised definition on incidence and outcomes of acute exacerbation of idiopathic pulmonary fibrosis

The revised definition of acute exacerbation (AE) in idiopathic pulmonary fibrosis (IPF) was proposed in 2016, but changes in the incidence and impact on prognosis of the re-defined AE compared to those of the previous definition remain unclear. Clinical data of 445 patients with IPF (biopsy proven cases: 165) were retrospectively reviewed. The median follow-up period was 36.8 months and 17.5% (n = 78) experienced AE more than once. The 1- and 3-year incidence rates of AE were 6.7% and 16.6%, respectively, and idiopathic AE accounted for 82.1% of AE. Older age, lower diffusing capacity of the lung for carbon monoxide and 10% relative decline in forced vital capacity for 6 months were independently associated with AE. The in-hospital mortality rate following AE was 29.5%. In the multivariable analysis, AE was independently associated with poor prognosis in patients with IPF. Compared to the old definition, the revised definition relatively increased the incidence of AE by 20.4% and decreased the in-hospital mortality by 10.1%. Our results suggest that the revised definition affects approximately 20% increase in the incidences and 10% reduction in the in-hospital mortality of AE defined by the past definition.

Post-tuberculosis lung disease: a comparison of Brazilian, Italian, and Mexican cohorts

Objective:

To evaluate lung function in a cohort of patients with a history of pulmonary tuberculosis in Brazil, as well as to evaluate the decline in lung function over time and compare it with that observed in similar cohorts in Mexico and Italy.

Methods:

The three cohorts were compared in terms of age, smoking status, pulmonary function test results, six-minute walk test results, and arterial blood gas results. In the Brazilian cohort, pulmonary function test results, six-minute walk test results, and arterial blood gas results right after the end of tuberculosis treatment were compared with those obtained at the end of the follow-up period.

Results:

The three cohorts were very different regarding pulmonary function test results. The most common ventilatory patterns in the Brazilian, Italian, and Mexican cohorts were an obstructive pattern, a mixed pattern, and a normal pattern (in 58 patients [50.9%], in 18 patients [41.9%], and in 26 patients [44.1%], respectively). Only 2 multidrug-resistant tuberculosis cases were included in the Brazilian cohort, whereas, in the Mexican cohort, 27 cases were included (45.8%). Mean PaO₂ and mean SaO₂ were lower in the Mexican cohort than in the Brazilian cohort (p < 0.0001 and p < 0.002 for PaO₂ and SaO₂, respectively). In the Brazilian cohort, almost all functional parameters deteriorated over time.

Conclusions:

This study reinforces the importance of early and effective treatment of drug-susceptible tuberculosis patients, because multidrug-resistant tuberculosis increases lung damage. When patients complete their tuberculosis treatment, they should be evaluated as early as possible, and, if post-tuberculosis lung disease is diagnosed, they should be managed and offered pulmonary rehabilitation because there is evidence that it is effective in these patients.

Baseline serum Krebs von den Lungen-6 as a biomarker for the disease progression in idiopathic pulmonary fibrosis

Disease progression (DP) is an important parameter for the prognosis of idiopathic pulmonary fibrosis (IPF). This study aimed to evaluate the baseline serum biomarkers for predicting the DP in IPF. Seventy-four patients who were diagnosed with IPF and had their serum Krebs von den Lungen-6 (KL-6) and monocyte count, which might be associated with prognosis of IPF, checked more than twice were included. KL-6 ≥ 1000 U/mL and monocyte ≥ 600/μL were arbitrarily set as the cut-off values for DP. The DP was defined as a 10% reduction in forced vital capacity, a 15% reduction in diffusing capacity of the lung for carbon monoxide relative to the baseline, or disease-related mortality. Of the 74 patients, 18 (24.3%) were defined as having DP. The baseline KL-6 level was significantly increased in the DP group compared to the stable disease group (median, 1228.0 U/mL vs. 605.5 U/mL, P = 0.019). Multivariate Cox analyses demonstrated that a high KL-6 level (KL-6 ≥ 1000 U/mL; hazard ratio, 2.761 or 2.845; P = 0.040 or 0.045) was independently associated with DP in each model. The baseline serum KL-6 level might be a useful biomarker for DP in IPF.

Functional disorders of the respiratory system in patients with penetrating lung wounds: study prospective design

Background. Lung function tests should be performed to patients with penetrating wounds of the lungs to identify lung function disorders, and the data obtained should be taken into account when correcting medical treatment and prescribing individual medical rehabilitation programs. The aim was to study the impact of penetrating lung wounds on the lung function in the early recovery period. Materials and methods. 13 patients were enrolled in the study, 100% male, median age 26 [21; 31] years. Spirometry, body plethysmography, and a diffusion test were performed on an average of 14 days from the injury. Results. A prospective cross-sectional study was performed. A moderate decrease in the vital capacity (VC), the forced vital capacity (FVC), the volume of forced exhalation in the first second (FEV1) was revealed while the total lung capacity (TLCpl) and the FEV1/FVC ratio were within normal values. However, in 2 (15.4%) and 3 (23%) patients, a restrictive ventilation disorders (TLC lower limit of normal) was detected when using Global Lung Function Initiative (GLI) and European Community for Steel and Coal (ECSC) 1993 predicted value system, respectively. The residual lung (RV) and RV/TLCpl were increased. Functional residual capacity (FRC), FRCpl/TLCpl, airway resistance remained within normal values. The diffusion lung capacity impairment was detected in 92.3% and 61.5% cases according to the ECSC 1993 and the GLI system, respectively. Conclusion. In the early period of recovery after penetrating lung wounds, a nonspecific pattern of ventilation disorders was the most often abnormality namely a decrease in VC while TLC and FEV1/FVC were within normal values. Less frequently, the classic restrictive pattern of ventilation disorders was diagnosed. Besides, the diffusion lung capacity impairment was detected. The system of predicted values has a significant impact on the frequency of detection of the lung function disorders. The revealed functional disorders should be taken into account for adjusting medical and rehabilitation interventions.

Reduction of Lung Hyperinflation Improves Cardiac Preload, Contractility, and Output in Emphysema: A Prospective Cardiac Magnetic Resonance Study in Patients Who Received Endobronchial Valves

RATIONALE

Pulmonary hyperinflation in patients with Chronic Obstructive Pulmonary Disease (COPD) has been related to smaller cardiac chamber sizes and impaired cardiac function. Nowadays, bronchoscopic lung volume reduction (BLVR) with endobronchial valves is a treatment option to reduce pulmonary hyperinflation in patients with severe emphysema.

OBJECTIVES

We hypothesized that reduction of hyperinflation would improve cardiac preload in this patient group. In addition, we investigated whether the treatment would result in elevated pulmonary artery pressures due to pulmonary vascular bed reduction.

METHODS

We included patients with emphysema and severe hyperinflation (defined by a baseline residual volume >175% of predicted) who were eligible for BLVR with endobronchial valves. Cardiac magnetic resonance imaging was obtained one day prior to treatment and at eight week follow-up. Primary endpoint was cardiac preload, as measured by the right ventricle end-diastolic volume index (RVEDVI). As secondary endpoints, we measured indexed end-diastolic and end-systolic volumes of the right ventricle, left atrium, and left ventricle, pulmonary artery pressures, cardiac output, ejection fraction, and strain.

MEASUREMENTS AND MAIN RESULTS

Twenty-four patients were included. At eight week follow-up, RVEDVI was significantly improved (+7.9 ml/m2, SD 10.0, p=0.001). In addition to increased stroke volumes, we found significantly higher ejection fractions and strain measurements. Although cardiac output was significantly increased (+0.9L/min, SD 1.5, p=0.007), there were no changes in pulmonary artery pressures.

CONCLUSIONS

We found that reduction of hyperinflation using BLVR with endobronchial valves significantly improved cardiac preload, myocardial contractility, and cardiac output, without changes in pulmonary artery pressures. Clinical trial registered with ClinicalTrials.gov (NCT03474471).

Paraesophageal hernia repair with laparoscopic Toupet fundoplication: impact on pulmonary function, respiratory symptoms and quality of life

BACKGROUND

Paraesophageal hiatal hernia (PEH) is characterized by protrusion of intra-abdominal organs into the posterior mediastinum. Respiratory symptoms and reduced pulmonary function have been described as possibly related to lung compression.

OBJECTIVE

To assess the effect of laparoscopic Toupet fundoplication (LTF) for PEH repair on pulmonary function, measured with pulmonary function tests (PFTs), and respiratory symptoms.

METHODS

Retrospective, single-center, cohort study (November 2015-2020). All patients that completed pre- and postoperative (12 months) PFTs assessment were included. The gastroesophageal reflux disease health-related quality of life (GERD-HRQL), reflux symptom index (RSI) and short form-36 (SF-36) were used.

RESULTS

Overall, 71 patients were included. The median age was 67.1 years and the majority were females (78.8%). Baseline PFTs were within normal limits in 91% of patients. At 12 month follow-up, total lung capacity (TLC) (4.77 vs. 5.07 L; p = 0.0251), vital capacity (VC) (2.97 vs. 3.31 L; p = 0.0065), forced expiratory volume in one second (FEV1) (2.07 vs. 2.44 L; p < 0.001) and forced vital capacity (FVC) (2.78 vs. 3.19 L; p < 0.001) were significantly improved. No significant differences were found for diffusing capacity of lung for carbon monoxide (DLCO) (17.09 vs. 17.24; p = 0.734), and FEV1/FVC (0.77 vs. 0.77; p = 0.967). Interestingly, improvements were more pronounced in patients with large PEH (type IIIb and IV). At 12 month follow-up, both gastrointestinal and respiratory symptoms were significantly improved and 94% of patients were satisfied with the operation. The GERD-HRQL (18.1 ± 7.9 vs. 4.01 ± 2.4; p = 0.001), RSI (37.8 ± 9.7 vs. 10.6 ± 8.9; p < 0.001) and all SF-36 items were improved.

CONCLUSIONS

LTF for the treatment of PEH is safe and seems to be effective up to 12 month follow-up with improved lung volumes, spirometry values, quality of life, gastrointestinal and respiratory symptoms.

Differential Effects of Cannabis and Tobacco on Lung Function in Mid-Adult Life

Rationale: Evidence suggests that the effects of smoking cannabis on lung function are different from tobacco. However, long-term follow-up data are scarce and mostly based on young adults. Objectives: To assess the effects of cannabis and tobacco on lung function in mid-adult life. Methods: Cannabis and tobacco use were reported at ages 18, 21, 26, 32, 38, and 45 years in a population-based cohort study of 1,037 participants. Spirometry, plethysmography, and carbon monoxide transfer factor were measured at age 45. Associations between lung function and cannabis use were adjusted for tobacco use. Measurements and Main Results: Data were available from 881 (88%) of 997 surviving participants. Cumulative cannabis use was associated with lower FEV₁/FVC ratios, owing to a tendency toward higher FVCs. Cannabis use was also associated with higher TLC, FRC, residual volume, and Va along with lower midexpiratory flows, airway conductance, and transfer factor. Quitting regular cannabis use between assessments was not associated with changes in spirometry. Conclusions: Cannabis use is associated with higher lung volumes, suggesting hyperinflation. There is evidence of increased large-airway resistance and lower midexpiratory airflow, but impairment of FEV₁/FVC ratio is because of higher FVC. This pattern of effects is different to those of tobacco. We provide the first evidence that lifetime cannabis use may be associated with impairment of gas transfer.

Selective serotonin reuptake inhibitors and lung function in the multi-ethnic study of atherosclerosis lung study

OBJECTIVE

Depression in patients with Chronic Obstructive Pulmonary Disease (COPD) has been shown to be chronic and potentially increase the burden of symptoms. Selective serotonin reuptake inhibitors (SSRIs) have anti-inflammatory and serotonergic effects that may improve lung function. We hypothesized that participants taking SSRIs have better lung function than those not taking SSRIs. The dataset was the Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study. Use of SSRIs was assessed by medication inventory; spirometry was conducted following standard guidelines; dyspnea ratings were self-reported.

RESULTS

Contrary to our hypothesis, FEV1 was lower, and odds of dyspnea were higher among participants taking SSRIs as compared with those not taking an antidepressant; these differences persisted even with control for potential confounders including depressive symptoms. We found no evidence of a beneficial association between SSRI use and lung function or dyspnea in a large US-based cohort.

Myositis-associated Interstitial Lung Disease: Clinical Characteristics and Factors Related to Pulmonary Function Improvement: A Latin-American Multicenter Cohort Study

BACKGROUND AND OBJECTIVES

ILD patients can be positive to highly specific autoantibodies of connective tissue diseases (CTD). Among them stand out myositis-specific and associated autoantibodies (MSA/MAA). There is limited knowledge about treatment response and prognosis of ILD patients positive to MSA/MAA (MSA/MAA-ILD). Our aim was to describe clinical, radiological and pulmonary function (PF) of MSA/MAA-ILD Latin-American patients and risk factors associated to PF at onset and long term follow up.

METHODS

Multicentric retrospective study of MSA/MAA-ILD patients evaluated between 2016 and 2018 in 3 ILD clinics in Latin America. Clinical, functional and tomographic variables were described. Variables associated with poor baseline PF and associated with functional improvement (FI) were analyzed in a multivariate logistic regression model.

RESULTS

We included 211 patients, 77.4% female, mean age 57 years old. Most frequent MSA/MAA were Ro-52 and Jo-1. Poor baseline PF was associated to ILD as initial diagnosis and NSIP/OP HRCT pattern. 121 patients were included in the follow up PF analysis: 48.8% remained stable and 33% had a significant FI. In multivariate analysis, OP pattern on HRCT was associated with FI. Systemic symptoms from the beginning and the absence of sclerodactyly showed a trend to be associated with FI.

CONCLUSIONS

Worse baseline PF could be related to the absence of extra-thoracic symptoms and "classic" antibodies in CTD (ANA), which causes delay in diagnosis and treatment. In contrast, FI could be related to the presence of extra-thoracic signs that allow timely diagnosis and therapy, and more acute and subacute forms of ILD, such as OP pattern.

Quantitative imaging analysis detects subtle airway abnormalities in symptomatic military deployers

Background

Exposure to inhalational hazards during post-9/11 deployment to Southwest Asia and Afghanistan puts military personnel at risk for respiratory symptoms and disease. Pulmonary function and qualitative chest high resolution computed tomography (HRCT) are often normal in “deployers” with persistent respiratory symptoms. We explored the utility of quantitative HRCT imaging markers of large and small airways abnormalities, including airway wall thickness, emphysema, and air trapping, in symptomatic deployers with clinically-confirmed lung disease compared to controls.

Methods

Chest HRCT images from 45 healthy controls and 82 symptomatic deployers with asthma, distal lung disease or both were analyzed using Thirona Lung quantification software to calculate airway wall thickness (by Pi10), emphysema (by percentage of lung volume with attenuation < -950 Hounsfield units [LAA%-950]), and three parameters of air trapping (expiratory/inspiratory total lung volume and mean lung density ratios, and LAA%-856). SAS v.9.4 was used to compare demographic and clinical characteristics between deployers and controls using Chi-Square, Fisher Exact or t-tests. Linear regression was used to assess relationships between pulmonary function and quantitative imaging findings.

Results

Gender and smoking status were not statistically significantly different between groups, but deployers were significantly younger than controls (42 vs 58 years, p < 0.0001), had higher body mass index (31 vs 28 kg/m², p = 0.01), and had fewer total smoking pack-years (8 vs. 26, p = 0.007). Spirometric measures were not statistically significantly different between groups. Pi10 and LAA%-950 were significantly elevated in deployers compared to controls in unadjusted analyses, with the emphysema measure remaining significantly higher in deployers after adjustment for age, sex, smoking, BMI, and expiratory total lung volume. Air trapping parameters were more common in control images, likely due to differences in age and smoking between groups. Among deployers, LAA%-950 and Pi10 were significantly correlated with spirometric markers of obstruction based on ratio of forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) and/or percent predicted FEV1.

Conclusions

Quantitative chest HRCT imaging analysis identifies emphysema in deployers with asthma and distal lung disease, and may be useful in detecting and monitoring deployment-related lung disease in a population where spirometry is typically normal.

Fatigue Is a Major Symptom at COVID-19 Hospitalization Follow-Up

Persistent symptoms after hospitalization with COVID-19 are common, but the frequency and severity of these symptoms are insufficiently understood. We aimed to describe symptoms and pulmonary function after hospitalization with COVID-19. Patients hospitalized with COVID-19 in Central Denmark Region were invited for follow-up 3 months after discharge. Clinical characteristics, patient reported outcomes (Fatigue Assessment Scale (FAS), anxiety and depression (HADS)), symptoms, pulmonary function test and 6-min walk test were collected. We included 218 patients (mean age 59.9 (95% CI: 58.2, 61.7), 59% males). Fatigue, dyspnea and impaired concentration were the most prevalent symptoms at follow-up. Using FAS, 47% reported mild-to-moderate fatigue and 18% severe fatigue. Mean HADS was 7.9 (95% CI: 6.9, 8.9). FAS was correlated to HADS (β = 0.52 (95% CI: 0.44, 0.59, p < 0.001)). Mean DLCO was 80.4% (95% CI: 77.8, 83.0) and 45% had DLCO ˂ 80%. Mean DLCO was significantly reduced in patients treated in the ICU (70.46% (95% CI 65.13, 75.79)). The highest FAS and HADS were seen in patients with the shortest period of hospitalization (2.1 days (95% CI: 1.4, 2.7)) with no need for oxygen. In conclusion, fatigue is a common symptom after hospitalization for COVID-19 and ICU treatment is associated to decreased diffusion capacity.

Frailty assessment for COVID-19 follow-up: a prospective cohort study

BACKGROUND

The Clinical Frailty Scale (CFS) is increasingly used for clinical decision making in acute care but little is known about frailty after COVID-19.

OBJECTIVES

To investigate frailty and the CFS for post-COVID-19 follow-up.

METHODS

This prospective multicentre cohort study included COVID-19 survivors aged ≥50 years presenting for a follow-up visit ≥3 months after the acute illness. Nine centres retrospectively collected pre-COVID-19 CFS and prospectively CFS at follow-up. Three centres completed the Frailty Index (FI), the short physical performance battery (SPPB), 30 s sit-to-stand test and handgrip strength measurements. Mixed effect logistic regression models accounting for repeated measurements and potential confounders were used to investigate factors associated with post-COVID-19 CFS. Criterion and construct validity were determined by correlating the CFS to other concurrently assessed frailty measurements and measures of respiratory impairment, respectively.

RESULTS

Of the 288 participants 65% were men, mean (SD) age was 65.1 (9) years. Median (IQR) CFS at follow-up was 3 (2-3), 21% were vulnerable or frail (CFS ≥4). The CFS was responsive to change, correlated with the FI (r=0.69, p<0.001), the SPPB score (r=-0.48, p<0.001) (criterion validity) and with the St George's Respiratory Questionnaire score (r=0.59, p<0.001), forced vital capacity %-predicted (r=-0.25, p<0.001), 6 min walk distance (r=-0.39, p<0.001) and modified Medical Research Council (mMRC) (r=0.59, p<0.001). Dyspnoea was significantly associated with a higher odds for vulnerability/frailty (per one mMRC adjusted OR 2.01 (95% CI 1.13 to 3.58), p=0.02).

CONCLUSIONS

The CFS significantly increases with COVID-19, and dyspnoea is an important risk factor for post-COVID-19 frailty and should be addressed thoroughly.

Correlation of respiratory oscillometry with CT image analysis in a prospective cohort of idiopathic pulmonary fibrosis

Background

Markers of idiopathic pulmonary fibrosis (IPF) severity are based on measurements of forced vital capacity (FVC), diffusing capacity (DLCO) and CT. The pulmonary vessel volume (PVV) is a novel quantitative and independent prognostic structural indicator derived from automated CT analysis. The current prospective cross-sectional study investigated whether respiratory oscillometry provides complementary data to pulmonary function tests (PFTs) and is correlated with PVV.

Methods

From September 2019 to March 2020, we enrolled 89 patients with IPF diagnosed according to international guidelines. We performed standard spectral (5–37 Hz) and novel intrabreath tracking (10 Hz) oscillometry followed by PFTs. Patients were characterised with the gender-age-physiology (GAP) score. CT images within 6 months of oscillometry were analysed in a subgroup (26 patients) using automated lung texture analysis. Correlations between PFTs, oscillometry and imaging variables were investigated using different regression models.

Findings

The cohort (29F/60M; age=71.7±7.8 years) had mild IPF (%FVC=70±17, %DLCO=62±17). Spectral oscillometry revealed normal respiratory resistance, low reactance, especially during inspiration at 5 Hz (X5in), elevated reactance area and resonance frequency. Intrabreath oscillometry identified markedly low reactance at end-inspiration (XeI). XeI and X5in strongly correlated with FVC (r²=0.499 and 0.435) while XeI was highly (p=0.004) and uniquely correlated with the GAP score. XeI and PVV exhibited the strongest structural-functional relationship (r²=0.690), which remained significant after adjusting for %FVC, %DLCO and GAP score.

Interpretation

XeI is an independent marker of IPF severity that offers additional information to standard PFTs. The data provide a cogent rationale for adding oscillometry in IPF assessment.

Prospective longitudinal evaluation of hospitalised COVID-19 survivors 3 and 12 months after discharge

Background

Long-term outcome data of coronavirus disease 2019 (COVID-19) survivors are needed to understand their recovery trajectory and additional care needs.

Methods

A prospective observational multicentre cohort study was carried out of adults hospitalised with COVID-19 from March through May 2020. Workup at 3 and 12 months following admission consisted of clinical review, pulmonary function testing, 6-min walk distance (6MWD), muscle strength, chest computed tomography (CT) and quality of life questionnaires. We evaluated factors correlating with recovery by linear mixed effects modelling.

Results

Of 695 patients admitted, 299 and 226 returned at 3 and 12 months, respectively (median age 59 years, 69% male, 31% severe disease). About half and a third of the patients reported fatigue, dyspnoea and/or cognitive impairment at 3 and 12 months, respectively. Reduced 6MWD and quadriceps strength were present in 20% and 60% at 3 months versus 7% and 30% at 12 months. A high anxiety score and body mass index correlated with poor functional recovery. At 3 months, diffusing capacity for carbon monoxide (D_LCO) and total lung capacity were below the lower limit of normal in 35% and 18%, decreasing to 21% and 16% at 12 months; predictors of poor D_LCO recovery were female sex, pre-existing lung disease, smoking and disease severity. Chest CT improved over time; 10% presented non-progressive fibrotic changes at 1 year.

Conclusion

Many COVID-19 survivors, especially those with severe disease, experienced limitations at 3 months. At 1 year, the majority showed improvement to almost complete recovery. To identify additional care or rehabilitation needs, we recommend a timely multidisciplinary follow-up visit following COVID-19 admission.

Most hospitalised #COVID19 survivors show promising recovery 1 year after discharge, although mild symptoms may linger. Severe impairments are rare, but this study suggests an evaluation of the individual care needs after discharge.https://bit.ly/3sZK45x

Automated estimation of total lung volume using chest radiographs and deep learning

Background

Total lung volume is an important quantitative biomarker and is used for the assessment of restrictive lung diseases.

Purpose

In this study, we investigate the performance of several deep‐learning approaches for automated measurement of total lung volume from chest radiographs.

Methods

About 7621 posteroanterior and lateral view chest radiographs (CXR) were collected from patients with chest CT available. Similarly, 928 CXR studies were chosen from patients with pulmonary function test (PFT) results. The reference total lung volume was calculated from lung segmentation on CT or PFT data, respectively. This dataset was used to train deep‐learning architectures to predict total lung volume from chest radiographs. The experiments were constructed in a stepwise fashion with increasing complexity to demonstrate the effect of training with CT‐derived labels only and the sources of error. The optimal models were tested on 291 CXR studies with reference lung volume obtained from PFT. Mean absolute error (MAE), mean absolute percentage error (MAPE), and Pearson correlation coefficient (Pearson's r) were computed.

Results

The optimal deep‐learning regression model showed an MAE of 408 ml and an MAPE of 8.1% using both frontal and lateral chest radiographs as input. The predictions were highly correlated with the reference standard (Pearson's r = 0.92). CT‐derived labels were useful for pretraining but the optimal performance was obtained by fine‐tuning the network with PFT‐derived labels.

Conclusion

We demonstrate, for the first time, that state‐of‐the‐art deep‐learning solutions can accurately measure total lung volume from plain chest radiographs. The proposed model is made publicly available and can be used to obtain total lung volume from routinely acquired chest radiographs at no additional cost. This deep‐learning system can be a useful tool to identify trends over time in patients referred regularly for chest X‐ray.

Vitamin D supplementation in chronic obstructive pulmonary disease patients with low serum vitamin D: a randomized controlled trial

BACKGROUND

Vitamin D deficiency is frequently found in patients with chronic obstructive pulmonary disease (COPD). Vitamin D has antimicrobial, anti-inflammatory, and immunomodulatory effects. Therefore, supplementation may prevent COPD exacerbations, particularly in deficient patients.

OBJECTIVES

We aimed to assess the effect of vitamin D supplementation on exacerbation rate in vitamin D-deficient patients with COPD.

METHODS

We performed a multicenter, double-blind, randomized controlled trial. COPD patients with ≥1 exacerbations in the preceding year and a vitamin D deficiency (15-50 nmol/L) were randomly allocated in a 1:1 ratio to receive either 16,800 International Units (IU) vitamin D3 or placebo once a week during 1 y. Primary outcome of the study was exacerbation rate. Secondary outcomes included time to first and second exacerbations, time to first and second hospitalizations, use of antibiotics and corticosteroids, pulmonary function, maximal respiratory mouth pressure, physical performance, skeletal muscle strength, systemic inflammatory markers, nasal microbiota composition, and quality of life.

RESULTS

The intention-to-treat population consisted of 155 participants. Mean ± SD serum 25-hydroxyvitamin D [25(OH)D] concentration after 1 y was 112 ± 34 nmol/L in the vitamin D group, compared with 42 ± 17 nmol/L in the placebo group. Vitamin D supplementation did not affect exacerbation rate [incidence rate ratio (IRR): 0.90; 95% CI: 0.67, 1.21]. In a prespecified subgroup analysis in participants with 25(OH)D concentrations of 15-25 nmol/L (n = 31), no effect of vitamin D supplementation was found (IRR: 0.91; 95% CI: 0.43, 1.93). No relevant differences were found between the intervention and placebo groups in terms of secondary outcomes.

CONCLUSIONS

Vitamin D supplementation did not reduce exacerbation rate in COPD patients with a vitamin D deficiency.This trial was registered at clinicaltrials.gov as NCT02122627.

MRI Shows Lung Perfusion Changes after Vaping and Smoking

Background Evidence regarding short-term effects of electronic nicotine delivery systems (ENDS) and tobacco smoke on lung ventilation and perfusion is limited. Purpose To examine the immediate effect of ENDS exposure and tobacco smoke on lung ventilation and perfusion by functional MRI and lung function tests. Materials and Methods This prospective observational pilot study was conducted from November 2019 to September 2021 (substudy of randomized controlled trial NCT03589989). Included were 44 healthy adult participants (10 control participants, nine former tobacco smokers, 13 ENDS users, and 12 active tobacco smokers; mean age, 41 years ± 12 [SD]; 28 men) who underwent noncontrast-enhanced matrix pencil MRI and lung function tests before and immediately after the exposure to ENDS products or tobacco smoke. Baseline measurements were acquired after 2 hours of substance abstinence. Postexposure measurements were performed immediately after the exposure. MRI showed semiquantitative measured impairment of lung perfusion (R_Q) and fractional ventilation (R_FV) impairment as percentages of affected lung volume. Lung clearance index (LCI) was assessed by nitrogen multiple-breath washout to capture ventilation inhomogeneity and spirometry to assess airflow limitation. Absolute differences were calculated with paired Wilcoxon signed-rank test and differences between groups with unpaired Mann-Whitney test. Healthy control participants underwent two consecutive MRI measurements to assess MRI reproducibility. Results MRI was performed and lung function measurement was acquired in tobacco smokers and ENDS users before and after exposure. MRI showed a decrease of perfusion after exposure (R_Q, 8.6% [IQR, 7.2%-10.0%] to 9.1% [IQR, 7.8%-10.7%]; P = .03) and no systematic change in R_FV (P = .31) among tobacco smokers. Perfusion increased in participants who used ENDS after exposure (R_Q, 9.7% [IQR, 7.1%-10.9%] to 9.0% [IQR, 6.9%-10.0%]; P = .01). R_FV did not change (P = .38). Only in tobacco smokers was LCI elevated after smoking (P = .02). Spirometry indexes did not change in any participants. Conclusion MRI showed a decrease of lung perfusion after exposure to tobacco smoke and an increase of lung perfusion after use of electronic nicotine delivery systems. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Kligerman in this issue.

The global lung function initiative 2021 (GLI-2021) norms provide mixed results for static lung volumes (SLVs) in Algerian adults

The validity of the GLI-2021 norms for SLVs in healthy Algerian adults has not been assessed. To ascertain how well do the GLI-2021 norms fit to contemporary SLVs data in Algerian adults. This was a cross-sectional study involving 481 (n = 242 females) healthy non-smoking adults recruited from the Algiers general population. All participants underwent a clinical examination and a plethysmography. Z-scores for slow vital capacity (SVC), functional residual capacity (FRC), residual volume (RV), total lung capacity (TLC), expiratory reserve volume (ERV), inspiratory capacity (IC), and RV/TLC were calculated. The mean difference between the determined and the predicted values (∆value) of SLVs were calculated. The GLI-2021 norms would be considered as reflective of contemporary Algerian SLVs if the total sample mean z-scores were in the normal range (ie; −0.5 to +0.5). The participants’ means ± SDs of age and height were 46.4 ± 16.4 years and 166 ± 10 cm, respectively. The determined SLVs were significantly different from those predicted (∆values means ± SDs were −170 ± 470 ml for IC, −100 ± 490 ml for SVC, 170 ± 400 ml for ERV, 240 ± 620 ml for TLC, 370 ± 340 ml for RV, 480 ± 480 ml for FRC, and 5.28 ± 4.38% for RV/TLC). The means ± SDs z-scores for IC, SVC, ERV, and TLC were in the normal range (−0.29 ± 0.88, −0.17 ± 0.94, 0.29 ± 0.77, and 0.35 ± 0.86, respectively), but those of RV, FRC, and RV/TLC were out of the normal range (0.74 ± 0.66, 0.75 ± 0.72, and 0.83 ± 0.75, respectively). In healthy Algerian adults, the GLI-2021 norms fit well to SVC, TLC, ERV, and IC, but they do not fit to FRC, RV, and RV/TLC.

Implementation of an Integrated Total Quality Management System in a Pulmonary Function Laboratory

BACKGROUND AND OBJECTIVES

A worldwide objective in the area of health is to offer high-quality services supported by certification strategies that contribute to improving standards for processes commonly used in medicine. However, few pulmonary function test laboratories (PFTLs) follow official standards in their daily operations or are organized around an integrated total quality management system (ITQMS) focused on their established processes. The aim was to determine the feasibility of implementing an ITQMS to accredit the International Organization for Standardization (ISO) 9001:2015 standard in a high-demand PFTL where 13 respiratory function tests are routinely performed together with teaching and research activities.

METHODS

This project was conducted at the PFTL of the Instituto Nacional de Enfermedades Respiratorias in Mexico City from November 2014 to August 2017 and involved the implementation of an ITQMS guided by ISO 9001:2015 in 5 phases: (1) the establishment of a work team; (2) the elaboration of situational diagnoses; (3) the development of guidelines for the ITQMS; (4) the implementation of the ITQMS model; and (5) the evaluation of the ITQMS.

RESULTS

Upon completing the 5 phases, an evaluation of the system by an internal audit identified 3 minor cases of nonconformity (NC), while additional observations and an external audit found 5 minor cases of NC. These issues were addressed through a root-cause analysis to establish an action plan for each one. At the end of the process, the institution was granted the ISO 9001:2015 certification for its 3 processes: medical attention in support of diagnoses, teaching, and research.

CONCLUSIONS

It is possible to implement an ISO quality management system as a routine operating methodology in a high-demand PFTL.

Growth and morbidity in infants with Congenital Diaphragmatic Hernia according to initial lung volume: A pilot study

Background In congenital diaphragmatic hernia (CDH) survivors, failure to thrive is a well-known complication, ascribed to several factors. The impact of lung volume on growth of CDH survivors is poorly explored. Our aim was to evaluate if, in CDH survivors, lung volume (LV) after extubation correlates with growth at 12 and 24 months of life. Methods LV (measured as functional residual capacity-FRC) was evaluated by multibreath washout traces with an ultrasonic flowmeter and helium gas dilution technique, shortly after extubation. All CDH survivors are enrolled in a dedicated follow-up program. For the purpose of this study, we analyzed the correlation between FRC obtained shortly after extubation and anthropometric measurements at 12 and 24 months of age. We also compared growth between infants with normal lungs and those with hypoplasic lungs according to FRC values. A p < 0.05 was considered as statistically significant. Results We included in the study 22 CDH survivors who had FRC analyzed after extubation and auxological follow-up at 12 and 24 months of age. We found a significant correlation between FRC and weight Z-score at 12 months, weight Z-score at 24 months and height Z-score at 24 months. We also demonstrated that CDH infants with hypoplasic lungs had a significantly lower weight at 12 months and at 24 months and a significantly lower height at 24 months, when compared to infants with normal lungs. Conclusion We analyzed the predictive value of bedside measured lung volumes in a homogeneous cohort of CDH infants and demonstrated a significant correlation between FRC and growth at 12 and 24 months of age. An earlier identification of patients that will require an aggressive nutritional support (such as those with pulmonary hypoplasia) may help reducing the burden of failure to thrive.

Adjunctive inspiratory muscle training during a rehabilitation program in patients with breast cancer: an exploratory double-blind, randomized, controlled pilot study

Objective

To investigate whether inspiratory muscle training (IMT) offered adjunctively to an exercise training program reduces symptoms of dyspnea in survivors of breast cancer.

Design

Double-blind, parallel-group, randomized controlled trial.

Setting

Outpatient rehabilitation program in a university hospital.

Participants

Ninety-eight female patients with breast cancer who completed adjuvant treatment and subsequently entered cancer rehabilitation were screened for participation. Inclusion criteria were reduced inspiratory muscle strength and/or symptoms of dyspnea. Twenty patients (N=20) were randomly assigned to an intervention group (n=10) or a control group (n=10).

Intervention

Both groups received a 3-month exercise training program in combination with either IMT (intervention) or sham-IMT (control).

Main Outcome Measures

Changes in dyspnea intensity perception (10-point Borg Scale) at comparable time points (isotime) during constant work rate cycling was the primary outcome. Secondary outcomes included changes in respiratory muscle function, exercise capacity, and changes in symptoms of dyspnea during daily life (Transitional Dyspnea Index [TDI]).

Results

The intervention group achieved a larger reduction in exertional dyspnea at isotime compared with the control group (−1.8 points; 95% CI, −3.7 to 0.13; P=.066). The intervention group also exhibited larger improvements in dyspnea during daily life (TDI score, +2.9 points; 95% CI, 0.5-5.3; P=.022) and improved both respiratory muscle endurance (+472 seconds; 95% CI, 217-728; P=.001) and cycling endurance (+428 seconds; 95% CI, 223-633; P=.001) more than the control group.

Conclusions

Because of the limited sample size all obtained findings need to be interpreted with caution. The study offers initial insights into the potential of adjunctive IMT in selected survivors of breast cancer. Larger multicenter studies should be performed to further explore the potential role and general acceptance of this intervention as a rehabilitation tool in selected patients after breast cancer treatment.

Evaluation of the Global Lung Function Initiative reference equations in Belgian adults

Background

Over the past decade, the Global Lung Function Initiative (GLI) Network has published all-age reference equations on spirometry, diffusing capacity of the lung for carbon monoxide (D_LCO) and lung volumes.

Methods

We evaluated the appropriateness of these equations in an adult Caucasian population. Retrospective lung function data on subjects who performed tests prior to a diagnostic sleep investigation were analysed. From the medical records, lung healthy, lifetime nonsmoking, nonobese subjects were selected, resulting in a population of 1311 subjects (68% male; age range 18–88 years).

Results

Multiple linear regression analysis revealed that lung function z-scores did not differ between subjects with and without sleep apnoea but did depend on height and age. The average forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) z-score was 0 but exhibited an inverse association with height in both sexes (p<0.01). Values of FEV₁ and FVC in both sexes were larger than predicted (mean±sd z-score +0.30±0.96 or 104±13% pred; p<0.01). Overall, static lung volumes and D_LCO were adequately predicted. However, D_LCO z-scores were inversely associated with height in males and age in females (p<0.01). For all lung function indices, the observed scatter was reduced compared with the prediction. Therefore, for all indices <5% of the data were below the GLI-proposed lower limit of normal (LLN) threshold.

Conclusion

GLI reference equations provide an adequate fit in Belgian adults. However, the GLI-proposed LLN is too low for our Antwerp population, resulting in underdiagnosis of disease. Furthermore, airway obstruction and diffusion disorders might be misclassified due to height and age associations.

Overall, GLI reference equations for lung function appropriately describe the data in Belgian adults. However, airway obstruction and diffusion disorders might be misdiagnosed at age and height extremes, and the GLI LLN was too low in this population.https://bit.ly/3jdauLE

Role of hyperpnea in the relaxant effect of inspired CO2 on methacholine-induced bronchoconstriction

Inhaling carbon dioxide (CO₂) in humans is known to cause inconsistent effects on airway function. These could be due to direct effects of CO₂ on airway smooth muscle or to changes in minute ventilation (e). To address this issue, we examined the responses of the respiratory system to inhaled methacholine in healthy and mild asthmatics while breathing air or gas mixtures containing 2% or 4% CO₂. Respiratory mechanics were measured by a forced oscillation technique at 5 Hz during tidal breathing. At baseline, respiratory resistance (R₅) was significantly higher in asthmatics (2.53±0.38 cm H₂O•L^-1•s) than healthy subjects (2.11±0.42 cm H₂O•L^-1•s) (p=0.008) with room air. Similar values were observed with CO₂ 2% or 4% in the two groups. e, tidal volume (V_T), and breathing frequency (BF) significantly increased with CO₂-containing mixtures (p<0.001) with insignificant differences between groups. After methacholine, the increase in R₅ and the decrease in respiratory reactance (X₅) were significantly attenuated up to about 50% with CO₂-containing mixtures instead of room air in both asthmatic (p<0.001) and controls (p<0.001). Mediation analysis showed that the attenuation of methacholine-induced changes in respiratory mechanics by CO₂ was due to the increase in e (p=0.006 for R₅ and p=0.014 for X₅) independently of the increase in V_T or BF, rather than a direct effect of CO₂. These findings suggest that the increased stretching of airway smooth muscle by the CO₂-induced increase in e is a mechanism through which hypercapnia can attenuate bronchoconstrictor responses in healthy and mild asthmatic subjects.