Implications of Race Adjustment in Lung-Function Equations.

BACKGROUND: Adjustment for race is discouraged in lung-function testing, but the implications of adopting race-neutral equations have not been comprehensively quantified. METHODS: We obtained longitudinal data from 369,077 participants in the National Health and Nutrition Examination Survey, U.K. Biobank, the Multi-Ethnic Study of Atherosclerosis, and the Organ Procurement and Transplantation Network. Using these data, we compared the race-based 2012 Global Lung Function Initiative (GLI-2012) equations with race-neutral equations introduced in 2022 (GLI-Global). Evaluated outcomes included national projections of clinical, occupational, and financial reclassifications; individual lung-allocation scores for transplantation priority; and concordance statistics (C statistics) for clinical prediction tasks. RESULTS: Among the 249 million persons in the United States between 6 and 79 years of age who are able to produce high-quality spirometric results, the use of GLI-Global equations may reclassify ventilatory impairment for 12.5 million persons, medical impairment ratings for 8.16 million, occupational eligibility for 2.28 million, grading of chronic obstructive pulmonary disease for 2.05 million, and military disability compensation for 413,000. These potential changes differed according to race; for example, classifications of nonobstructive ventilatory impairment may change dramatically, increasing 141% (95% confidence interval [CI], 113 to 169) among Black persons and decreasing 69% (95% CI, 63 to 74) among White persons. Annual disability payments may increase by more than $1 billion among Black veterans and decrease by $0.5 billion among White veterans. GLI-2012 and GLI-Global equations had similar discriminative accuracy with regard to respiratory symptoms, health care utilization, new-onset disease, death from any cause, death related to respiratory disease, and death among persons on a transplant waiting list, with differences in C statistics ranging from -0.008 to 0.011. CONCLUSIONS: The use of race-based and race-neutral equations generated similarly accurate predictions of respiratory outcomes but assigned different disease classifications, occupational eligibility, and disability compensation for millions of persons, with effects diverging according to race. (Funded by the National Heart Lung and Blood Institute and the National Institute of Environmental Health Sciences.).

Comparative analysis of pulmonary ventilation distribution between low-cost and branded incentive spirometers using electrical impedance tomography in healthy adults: Study protocol.

BACKGROUND: The Incentive Spirometer (IS) increases lung volume and improves gas exchange by visually stimulating patients to take slow, deep breaths. It prevents respiratory complications and treats postoperative atelectasis in patients undergoing abdominal, thoracic, and neurosurgical procedures. Its effectiveness has been validated in studies that support improved lung capacities and volumes in individuals with respiratory complications, postoperative thoracic surgery, upper abdominal surgery, and bariatric surgery. The modified Pachón incentive spirometer (MPIS) is a cost-effective alternative to branded IS. It is crucial to validate whether the MPIS distributes ventilation as effectively as commercial devices do. Ventilation distribution will be measured using electrical impedance tomography. OBJECTIVE: The aim is to compare the distribution of pulmonary ventilation between the MPIS and another commercial IS in healthy adults using electrical impedance tomography. METHODS: A crossover clinical trial is proposed to evaluate the measurement of pulmonary ventilation distribution using EIT in a sample of healthy adults. All participants will use a commercial flow IS and the MPIS, with the order of assignment randomized. This research will use electrical impedance tomography to validate the operation of the MPIS. CONCLUSIONS: This study protocol will compare two incentive spirometers' impact on pulmonary ventilation, potentially endorsing the adoption of a cost-effective device to enhance accessibility for targeted populations. TRIAL REGISTRATION: The study was registered in ClinicalTrials.gov (NTC05532748).

Bronchodilator response assessment through impulse oscillometry system and spirometry in children and adolescents with cystic fibrosis.

OBJECTIVE: To investigate the effect of bronchodilator on the respiratory mechanics and pulmonary function of children and adolescents with cystic fibrosis. METHODS: Cross-sectional study on clinically stable children and adolescents with cystic fibrosis aged from six to 15 years. Participants underwent impulse oscillometry and spirometry evaluations before and 15 minutes after bronchodilator inhalation. The Kolmogorov-Smirnov test was applied to verify the sample distribution, and the Student's t-test and Wilcoxon test were used to compare the data before and after bronchodilator inhalation. RESULTS: The study included 54 individuals with a mean age of 9.7±2.8 years. The analysis showed a statistically significant improvement in impulse oscillometry and spirometry parameters after bronchodilator inhalation. However, according to the American Thoracic Society (ATS) and European Respiratory Society (ERS) recommendations (2020 and 2021), this improvement was not sufficient to classify it as a bronchodilator response. CONCLUSIONS: The use of bronchodilator medication improved respiratory mechanics and pulmonary function parameters of children and adolescents with cystic fibrosis; however, most patients did not show bronchodilator response according to ATS/ERS recommendations.

The Child Opportunity Index 2.0 and exacerbation-prone asthma in a cohort of urban children.

RATIONALE: Social determinants of health underlie disparities in asthma. However, the effects of individual determinants likely interact, so a summary metric may better capture their impact. The Child Opportunity Index 2.0 (COI) is one such tool, yet its association with exacerbation-prone (EP) asthma is unknown. OBJECTIVE: To investigate the association between the COI and EP asthma and clinical measures of asthma severity in children. METHODS: We analyzed data from two prospective observational pediatric asthma cohorts (n = 193). Children were classified as EP (≥1 exacerbation in the past 12 months) or exacerbation-null (no exacerbations in the past 5 years). Spirometry, exhaled nitric oxide, IgE, and Composite Asthma Severity Index (CASI) were obtained. The association between COI and EP status was assessed with logistic regression. We fit linear and logistic regression models to test the association between COI and each clinical measure. RESULTS: A 20-point COI decrease conferred 40% higher odds of EP asthma (OR 1.4; 95%CI 1.1-1.76). The effect was similar when adjusted for age and sex (OR 1.38, 95%CI 1.1-1.75) but was attenuated with additional adjustment for race and ethnicity (OR 1.19, 95%CI 0.92-1.54). A similar effect was seen for the Social/Economic and Education COI domains but not the Health/Environment Domain. A 20-point COI decrease was associated with an increase in CASI of 0.34. COI was not associated with other clinical measures. CONCLUSIONS: Lower COI was associated with greater odds of EP asthma. This highlights the potential use of the COI to understand neighborhood-level risk and identify community targets to reduce asthma disparities.

Novel Surface Topographic Assessment of Lung Volume and Pulmonary Function Tests in Idiopathic Scoliosis: A Preliminary Study.

OBJECTIVE: Severe spinal deformity results in restrictive pulmonary disease from thoracic distortions and lung-volume limitations. Though spirometry and body plethysmography are widely accepted tests for pulmonary function tests (PFTs), they are time-consuming and require patient compliance. This study investigates whether surface topographic [surface topography (ST)] measurements of body volume difference (BVD) and torso volume difference between maximum inhale and exhale correlate to values determined on PFTs. METHODS: This study included patients with idiopathic scoliosis and thoracic/thoracolumbar curves ≥40 degrees. Patients received ST scans, clinical examinations, and EOS biplanar radiographs on the same day. PFTs were performed within 3 months of ST/radiographic analysis. Univariate linear regression analysis was used to examine relationships between BVD, PFT values, and mean curves. RESULTS: Sixteen patients (14.6 ± 2.2 y, 69% females) with idiopathic scoliosis and mean thoracic/thoracolumbar curves of 62 degrees ± 15˚ degrees (45 degrees to 93 degrees) were assessed. BVD displayed statistically high-positive positive correlations with forced vital capacity ( R = 0.863, P < 0.0001), forced expiratory volume in 1 second ( R = 0.870, P < 0.001), vital capacity ( R = 0.802, P < 0.0001), and TLC ( R = 0.831, P < 0.0001. Torso volume difference showed similarly high positive correlations to forced vital capacity, forced expiratory volume in 1 second, vital capacity, and TLC, but not residual volume. No correlations emerged between the mean thoracic/thoracolumbar curve and BVD or PFT values. CONCLUSION: This study strongly endorses further investigation into ST scanning as an alternative to traditional PFTs for assessing pulmonary volumes. The noncontact and noninvasive nature of ST scanning presents a valuable alternative method for analyzing thoracic volume, particularly beneficial for patients unable to cooperate with standard PFTs. LEVEL OF EVIDENCE: Level II-prognostic.

Diagnosis and Severity Assessment of COPD Using a Novel Fast-Response Capnometer and Interpretable Machine Learning.

INTRODUCTION: Spirometry is the gold standard for COPD diagnosis and severity determination, but is technique-dependent, nonspecific, and requires administration by a trained healthcare professional. There is a need for a fast, reliable, and precise alternative diagnostic test. This study's aim was to use interpretable machine learning to diagnose COPD and assess severity using 75-second carbon dioxide (CO2) breath records captured with TidalSense's N-TidalTM capnometer. METHOD: For COPD diagnosis, machine learning algorithms were trained and evaluated on 294 COPD (including GOLD stages 1-4) and 705 non-COPD participants. A logistic regression model was also trained to distinguish GOLD 1 from GOLD 4 COPD with the output probability used as an index of severity. RESULTS: The best diagnostic model achieved an AUROC of 0.890, sensitivity of 0.771, specificity of 0.850 and positive predictive value (PPV) of 0.834. Evaluating performance on all test capnograms that were confidently ruled in or out yielded PPV of 0.930 and NPV of 0.890. The severity determination model yielded an AUROC of 0.980, sensitivity of 0.958, specificity of 0.961 and PPV of 0.958 in distinguishing GOLD 1 from GOLD 4. Output probabilities from the severity determination model produced a correlation of 0.71 with percentage predicted FEV1. CONCLUSION: The N-TidalTM device could be used alongside interpretable machine learning as an accurate, point-of-care diagnostic test for COPD, particularly in primary care as a rapid rule-in or rule-out test. N-TidalTM also could be effective in monitoring disease progression, providing a possible alternative to spirometry for disease monitoring.

The value of lung function assessment and Testin expression detection in clinicopathological features and prognosis of NSCLC patients.

OBJECTIVE: The aim of this study is to investigate the clinical value and potential prognostic significance of lung function assessment and Testin expression in non-small cell lung cancer (NSCLC) patients. METHODS: The NSCLC patients were classified into three groups according to lung function: group of normal lung function, group of PRISm (preserved ratio impaired spirometry) (FEV1, forced expiratory volume during the first second < 80% predicted and FEV1/FVC (forced vital capacity) ≥ 70%) and group of COPD (chronic obstructive pulmonary disease) (FEV1/FVC < 70%). The pre-operational clinicopathological characteristics of these patients were recorded and the markers of systemic inflammatory response, including neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), platelet to lymphocyte ratio (PLR) and eosinophils (EOS), were compared between three groups. The expression of Testin in NSCLC samples was detected by IHC and we further explored the correlation between Testin expression and clinicopathological characteristics and prognosis of NSCLC patients. Finally, Cox regression analysis was conducted to study the prognostic factors of NSCLC patients. RESULTS: Of the 158 NSCLC patients, percentages of normal lung function, PRISm and COPD were 41.4%, 22.8% and 36.1%, respectively. Patients with tumor in the left lung were more likely to have pulmonary dysfunction (PRISm and COPD) than the right lung. The markers of systemic inflammatory response showed differences to various degree in the three groups and NSCLC patients with PRISm or COPD presented more unfavorable prognosis than patients with normal function. The expression of Testin correlated with lymph node metastasis, TNM stage and tumor invasion of NSCLC patients. Moreover, patients with low Testin expression exhibited poorer disease-free survival and overall survival than those with high Testin expression. In Cox regression analysis, we found that PRISm, COPD and Testin expression served as prognostic factors in NSCLC patients. CONCLUSIONS: The presence of COPD or PRISm influenced systemic inflammatory response and prognosis of NSCLC patients. Testin expression correlated with clinicopathological features and could be potentially used as a prognostic marker in NSCLC.

Implementation and Cost Analysis of a Novel Silicosis Case-Finding Program For Mine Workers in Rural Rwanda.

Little is known about the burden of silicosis in Africa, despite extensive mining and construction operations in the region putting numerous people at risk. The implementation experience and costs of case-finding for occupational lung disease in resource-limited settings are also currently unknown. We describe the first-ever silicosis case-finding project in rural Rwanda using chest X-ray, symptom questionnaires, and spirometry. This was coupled with routine noncommunicable disease case-finding for diabetes and hypertension. We performed an ingredient-based analysis of the costs of all case-finding activities. In 2022, over 25 days, 1,032 mine workers were included in the program, of which 1,014 (98.3%) completed silicosis case-finding activities. The total cost of the program was estimated to be US$38,656, representing a cost of US$37.49 per person. We conclude that conducting large-scale occupational lung disease case-finding is clinically and economically feasible in resource-limited settings and can be effectively integrated with routine noncommunicable disease case-finding.

Components of the Chronic Obstructive Pulmonary Disease Assessment Test Associated with the Exacerbation of Severe Chronic Obstructive Pulmonary Disease Patients.

INTRODUCTION: The chronic obstructive pulmonary disease (COPD) Assessment Test (CAT) score is widely used for evaluating the health status of patients diagnosed with COPD. The aim of this study was to identify which components of the CAT are associated with exacerbations in severe COPD patients. METHODS: Using data from the Korean COPD Subgroup Study (KOCOSS), we identified 3,440 COPD patients, among which 1,027 patients are classified as having severe COPD based on spirometry results. The CAT scores on 8 items were evaluated and classified into respiratory and non-respiratory categories. We analyzed the association between CAT item scores and moderate-to-severe exacerbations during study enrollment and the following years. RESULTS: Patients with a history of moderate-to-severe exacerbations had higher scores on non-respiratory CAT components. Longitudinal CAT scores on all items after enrollment were higher in the moderate-to-severe exacerbation group. Additionally, the frequency of severe exacerbations was associated with specific CAT components related to limited activities, confidence leaving home, sleeplessness, and energy. CONCLUSIONS: This study revealed that the non-respiratory CAT component scores were statistically significant factors for predicting the moderate-to-severe exacerbation of severe COPD patients. Non-respiratory symptoms and functional limitations should be considered in patients with severe COPD. Interventions, such as pulmonary rehabilitation, may be needed to improve patients' overall well-being and prevent exacerbations.

Assessment of functional diversities in patients with Asthma, COPD, Asthma-COPD overlap, and Cystic Fibrosis (CF).

The objectives of the present study were to evaluate the discriminating power of spirometric and plethysmographic lung function parameters to differenciate the diagnosis of asthma, ACO, COPD, and to define functional characteristics for more precise classification of obstructive lung diseases. From the databases of 4 centers, a total of 756 lung function tests (194 healthy subjects, 175 with asthma, 71 with ACO, 78 with COPD and 238 with CF) were collected, and gradients among combinations of target parameters from spirometry (forced expiratory volume one second: FEV1; FEV1/forced vital capacity: FEV1/FVC; forced expiratory flow between 25-75% FVC: FEF25-75), and plethysmography (effective, resistive airway resistance: sReff; aerodynamic work of breathing at rest: sWOB), separately for in- and expiration (sReffIN, sReffEX, sWOBin, sWOBex) as well as static lung volumes (total lung capacity: TLC; functional residual capacity: FRCpleth; residual volume: RV), the control of breathing (mouth occlusion pressure: P0.1; mean inspiratory flow: VT/TI; the inspiratory to total time ratio: TI/Ttot) and the inspiratory impedance (Zinpleth = P0.1/VT/TI) were explored. Linear discriminant analyses (LDA) were applied to identify discriminant functions and classification rules using recursive partitioning decision trees. LDA showed a high classification accuracy (sensitivity and specificity > 90%) for healthy subjects, COPD and CF. The accuracy dropped for asthma (~70%) and even more for ACO (~60%). The decision tree revealed that P0.1, sRtot, and VT/TI differentiate most between healthy and asthma (68.9%), COPD (82.1%), and CF (60.6%). Moreover, using sWOBex and Zinpleth ACO can be discriminated from asthma and COPD (60%). Thus, the functional complexity of obstructive lung diseases can be understood, if specific spirometric and plethysmographic parameters are used. Moreover, the newly described parameters of airway dynamics and the central control of breathing including Zinpleth may well serve as promising functional marker in the field of precision medicine.

REMOTE-ILD study: Description of the protocol for a multicentre, 12-month randomised controlled trial to assess the clinical and cost-effectiveness of remote monitoring of spirometry and pulse oximetry in patients with interstitial lung disease.

INTRODUCTION: Remote monitoring of home physiological measurements has been proposed as a solution to support patients with chronic diseases as well as facilitating virtual consultations and pandemic preparedness for the future. Daily home spirometry and pulse oximetry have been demonstrated to be safe and acceptable to patients with interstitial lung disease (ILD) but there is currently limited evidence to support its integration into clinical practice. AIM: Our aim is to understand the clinical utility of frequent remote physiological measurements in ILD and the impact of integrating these into clinical practice from a patient, clinical and health economic perspective. METHODS AND ANALYSIS: 132 patients with fibrotic ILD will be recruited and randomised to receive either usual care with remote digital monitoring of home spirometry and pulse oximetry or usual care alone for 12 months. All participants will complete health-related quality of life and experience questionnaires.The primary outcome compares the availability of spirometry measurements within the 2 weeks preceding planned clinic appointments. Secondary outcomes will explore other aspects of clinical and cost-effectiveness of the remote monitoring programme. ETHICS AND DISSEMINATION: The study has been approved by the Camden and Kings Cross Research Ethics Committee (22/LO/0309). All participants will provide informed consent.This study is registered with www. CLINICALTRIALS: gov (NCT05662124).The results of the study will be submitted for presentation at regional and national conferences and submitted for peer-reviewed publication. Reports will be prepared for study participants with the support from our public involvement representatives through the charity Action for Pulmonary Fibrosis.

Comparison of particles in exhaled air and multiple breath washout for assessment of small airway function in children with cystic fibrosis.

BACKGROUND: The introduction of modulator therapy for cystic fibrosis (CF) has led to an increased interest in the detection of small airway disease (SAD) as sensitive marker of treatment response. The particles in exhaled air (PExA) method, which records exhaled particle mass (PEx ng/L) and number (PExNR), detects SAD in adult patients. Our primary aim was to investigate if PExA outcomes in children with CF are different when compared to controls and associated with more severe disease. Secondary aims were to assess feasibility and repeatability of PExA in children with CF and to correlate PExA to multiple breath nitrogen washout (MBNW) as an established marker of SAD. METHODS: Thirteen healthy children (HC), 17 children with CF with normal lung function (CF-N) (FEV1 z-score ≥ -1.64) and six with airway obstruction (CF-AO) (FEV1 z-score < -1.64) between 8 and 18 years performed MBNW followed by PExA and spirometry. Children with CF repeated the measurements after 3 months. RESULTS: PEx ng/L and PExNR/L per liter of exhaled breath were similar between the three groups. The lung clearance index (LCI) was significantly higher in both CF-N and CF-AO compared to HC. All participants, except one, were able to perform PExA. Coefficient of variation for PEx ng/l was (median) 0.38, range 0-1.25 and PExNR/l 0.38, 0-1.09. Correlation between LCI and PEx ng/l was low, rs 0.32 (p = .07). CONCLUSION: PExA is feasible in children. In contrast to LCI, PExA did not differentiate healthy children from children with CF suggesting it to be a less sensitive tool to detect SAD.

Assessment of the Respiratory Health of Working US Coal Miners Since 2014-Radiography, Spirometry, and Symptom Assessments.

OBJECTIVE: The aim of the study is to summarize Coal Workers' Health Surveillance Program findings since 2014, focusing on prevalence of radiographic pneumoconiosis and abnormal spirometry by region. METHODS: Analysis included the most recent Coal Workers' Health Surveillance Program encounter for working miners during October 1, 2014-June 30, 2022. Central Appalachia consists of Kentucky, Virginia, and West Virginia. RESULTS: Pneumoconiosis prevalence was highest among underground miners, with 318 (6.2%) having radiographic evidence of disease. Central Appalachian miners were more likely to have evidence of pneumoconiosis (relative risk = 4.1 [3.4-5.0]) and abnormal spirometry (relative risk = 1.4 [1.2-1.6]) compared with all others. CONCLUSIONS: Central Appalachia is a hotspot for pneumoconiosis, as well as for other indicators of respiratory impairment in coal miners. Outreach for occupational respiratory health surveillance should focus on those areas most heavily affected, ensuring that miners are not hindered by perceived or actual barriers to this secondary intervention.

Early Evidence of Chronic Obstructive Pulmonary Disease Obscured by Race-Specific Prediction Equations.

Rationale: The identification of early chronic obstructive pulmonary disease (COPD) is essential to appropriately counsel patients regarding smoking cessation, provide symptomatic treatment, and eventually develop disease-modifying treatments. Disease severity in COPD is defined using race-specific spirometry equations. These may disadvantage non-White individuals in diagnosis and care. Objectives: Determine the impact of race-specific equations on African American (AA) versus non-Hispanic White individuals. Methods: Cross-sectional analyses of the COPDGene (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease) cohort were conducted, comparing non-Hispanic White (n = 6,766) and AA (n = 3,366) participants for COPD manifestations. Measurements and Main Results: Spirometric classifications using race-specific, multiethnic, and "race-reversed" prediction equations (NHANES [National Health and Nutrition Examination Survey] and Global Lung Function Initiative "Other" and "Global") were compared, as were respiratory symptoms, 6-minute-walk distance, computed tomography imaging, respiratory exacerbations, and St. George's Respiratory Questionnaire. Application of different prediction equations to the cohort resulted in different classifications by stage, with NHANES and Global Lung Function Initiative race-specific equations being minimally different, but race-reversed equations moving AA participants to more severe stages and especially between the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 0 and preserved ratio impaired spirometry groups. Classification using the established NHANES race-specific equations demonstrated that for each of GOLD stages 1-4, AA participants were younger, had fewer pack-years and more current smoking, but had more exacerbations, shorter 6-minute-walk distance, greater dyspnea, and worse BODE (body mass index, airway obstruction, dyspnea, and exercise capacity) scores and St. George's Respiratory Questionnaire scores. Differences were greatest in GOLD stages 1 and 2. Race-reversed equations reclassified 774 AA participants (43%) from GOLD stage 0 to preserved ratio impaired spirometry. Conclusions: Race-specific equations underestimated disease severity among AA participants. These effects were particularly evident in early disease and may result in late detection of COPD.

Respiratory Symptoms, Disease Burden, and Quality of Life in Australian Adults According to GOLD Spirometry Grades: Data from the BOLD Australia Study.

Purpose: Population data on the burden of chronic obstructive pulmonary disease (COPD) are often based on patient-reported diagnoses of COPD, emphysema or chronic bronchitis, without spirometry. We aimed to investigate the relationship between health burden, quality of life and severity of airway obstruction in Australian adults aged ≥40 years. Methods: We used data from the BOLD Australia study, which included randomly selected adults aged ≥40 years from six study sites to reflect the sociodemographic and geographic diversity of the Australian population (n = 3522). Participants with post-bronchodilator airflow limitation (ratio of forced expiratory volume in 1 second FEV1 to forced vital capacity <0.7) were grouped by GOLD spirometry grades 1-4. Quality of life was assessed with Short Form 12 (SF-12) Health Survey Questionnaire. Health burden was assessed as lost time off work or social activities, and healthcare utilization. Results: Of the study sample, 2969 participants did not have airflow limitation, 294 (8.4%) were classified as GOLD Grade 1, 212 (6.0%) as GOLD 2 and 43 (1.2%) as GOLD 3-4. Participants with higher GOLD grades had more respiratory symptoms, more comorbidities and greater burden than those with lower GOLD grades. The scores of mental and physical subscales of SF-12 were lower, indicating worse quality of life, from the no airflow limitation group to the GOLD 3-4 group (P = 0.03 and P < 0.001, respectively). Conclusion: Greater airflow limitation is associated with greater burden and poor quality of life. Interventions to prevent, or reduce the level of, airflow limitation will reduce the symptom burden and improve quality of life for patients.

Performance of spirometry assessment at TB diagnosis.

BACKGROUND: Spirometry is considered relevant for the diagnosis and monitoring of post-TB lung disease. However, spirometry is rarely done in newly diagnosed TB patients.METHODS: Newly diagnosed, microbiologically confirmed TB patients were recruited for the study. Spirometry was performed within 21 days of TB treatment initiation according to American Thoracic Society/European Respiratory Society guidelines. Spirometry analysis was done using Global Lung Initiative equations for standardisation.RESULTS: Of 1,430 eligible study participants, 24.7% (353/1,430) had no spirometry performed mainly due to contraindications and 23.0% (329/1,430) had invalid results; 52.3% (748/1,430) of participants had a valid result, 82.8% (619/748) of whom had abnormal spirometry. Of participants with abnormal spirometry, 70% (436/619) had low forced vital capacity (FVC), 6.1% (38/619) had a low ratio of forced expiratory volume in 1 sec (FEV1) to FVC, and 19.1% (118/619) had low FVC, as well as low FEV1/FVC ratio. Among those with abnormal spirometry, 26.3% (163/619) had severe lung impairment.CONCLUSIONS: In this population, a high proportion of not performed and invalid spirometry assessments was observed; this was addressed by removing tachycardia as a (relative) contraindication from the study guidance and retraining. The high proportion of patients with severe pulmonary impairment at the time of TB diagnosis suggests a huge morbidity burden and calls for further longitudinal studies on the relevance of spirometry in predicting chronic lung impairment after TB.

Mechanism of spirometry associated gastro-esophageal reflux in individuals undergoing esophageal assessment.

Persistent variability observed during spirometry, even when technical and personal factors are controlled, has prompted interest in uncovering its underlying mechanisms. Notably, our prior investigations have unveiled that spirometry has the potential to trigger gastro-esophageal reflux in a susceptible population. This current study embarks on elucidating the intricate mechanisms orchestrating reflux induced by spirometry. To achieve this, we enlisted twenty-four (24) participants exhibiting reflux symptoms for esophageal assessment. These participants underwent two sets of spirometry sessions, interspersed with a 10-minute intermission, during which we closely scrutinized fluid flow dynamics and esophageal function through high-resolution impedance esophageal manometry. Our comprehensive evaluation juxtaposed baseline manometric parameters against their equivalents during the initial spirometry session, the intervening rest period, and the subsequent spirometry session. Remarkably, impedance values, serving as a metric for fluid quantity, exhibited a substantial elevation during each spirometry session and the ensuing recovery interval in the pan-esophageal and hypopharyngeal regions when compared to baseline levels. Additionally, the resting pressure of the lower esophageal sphincter experienced a noteworthy reduction subsequent to the first bout of spirometry (13.6 ± 8.8 mmHg) in comparison to the baseline pressure (22.5 ± 13.3 mmHg). Furthermore, our observations unveiled a decline in spirometric parameters-FEV1 (0.14 ± 0.24 L, P = 0.042) and PEFR (0.67 L/s, P = 0.34)-during the second spirometry session when contrasted with the first session. Collectively, our study underscores the compelling evidence that spirometry maneuvers can elicit gastro-esophageal reflux by eliciting intra-esophageal pressure differentials and inducing temporary relaxation of the lower esophageal sphincter.