Comprehensive Lung Function Research Articles

Lung function in patients with asthma in the post-COVID period

Aim. To assess the lung function in patients with bronchial asthma (BA) after new-onset coronavirus infection.Materials and methods. Fifty-five patients who underwent COVID-19 participated in the study under conditions of voluntary informed consent. The main group consisted of 30 patients with mild BA, the comparison group – 25 patients without chronic respiratory diseases (CRD). According to chest computed tomography (CT) findings, the degree of lung parenchyma involvement was classified as follows: mild COVID-19 (CT 0 stage) in 14 patients; moderate COVID-19 (CT 1-2 stages) in 27 patients; and severe COVID-19 (CT 3-4 stages) in 14 patients. Lung function tests were conducted once, adhering to both Russian and international standards.Results. In patients with BA, obstructive pulmonary function impairment was predominant at CT 1-2 stages (79%), CT 0 stage (67%), and CT 3-4 stages (43%). Lung diffusion capacity (LDC) was impaired predominantly in CT 3-4 stages in both BA patients and those without CRD, occurring in 57% of cases. Analysis of lung function showed that LDC reduction was detected in 17% of BA cases and 24% of non-CRD cases. There were no statistically significant changes in pulmonary ventilation among BA patients with impaired LDC compared to patients without CRD.Conclusion. All patients with respiratory symptoms after COVID-19 should undergo comprehensive lung function assessment to identify bronchial obstruction, impaired lung diffusion capacity, and ensure timely intervention.

Implementation of electrical tomography in a medical measurement system for innovative imaging and area monitoring

LETS (Lung Electrical Tomography System) is an innovative medical system enabling comprehensive heart and lung function monitoring. It utilizes advanced techniques such as electrical impedance tomography (EIT), body surface potential mapping (BSPM), and electrical capacitance tomography (ECT) to provide accurate information about physiological parameters. The LETS system allows one-time examinations and continuous monitoring 24 hours a day. Remotely measuring and monitoring parameters such as the electrical activity of the heart muscle, blood flow, blood pressure, pulse, and lung aeration enables rapid identification and intervention in case of abnormalities. The system also allows for the detection of cardiac arrhythmias and other heart disorders, as well as the assessment of lung respiratory capacity and optimization of ventilation strategies. However, it's important to note that the LETS system has some limitations. For example, it may not be suitable for patients with certain pacemakers or other implanted devices. Overall, LETS represents a breakthrough in medical imaging, opening up new possibilities in diagnosing and monitoring heart and lung diseases. Its integration may contribute to improving patient care and increasing the effectiveness of medical interventions.

The impact of inflammatory cells on lung function in asthmatics in a cross sectional retrospect study

BackgroundLimited data exists on the impact of inflammatory cells and clinical characteristics on lung function in individuals with asthma. ObjectiveThe objective is to examine the correlation between increased inflammatory cells, asthma symptoms, and lung function in patients with asthma in a clinical setting. MethodsA retrospective cohort study was conducted on 234 individuals suspected of having asthma in Xian, China between January 2008 and December 2021. Of those, 143 patients with complete clinical feature and lung function data were enrolled to examine the relationship between increased inflammatory cells, asthma symptoms, and lung function. Basic characteristics, blood eosinophil count, blood neutrophil count, blood platelet count, blood C-reactive protein (CRP), and comprehensive lung function analysis were evaluated at each inpatient for the 143 adult asthmatics. The association between inflammatory cells and clinical parameters with pulmonary function was compared. ResultsThe results of the study showed that individuals in the alcohol intake group had elevated blood eosinophil count compared to those in the non-alcohol intake group (P = 0.024). Long-acting inhaled beta 2 agonists and antibiotic therapy were associated with lower blood eosinophil count (P = 0.021 and P = 0.049, respectively) compared to other therapy. There was a independent association between blood eosinophil counts and FEV1 pre- and post-therapy in asthma but there was a markedly correlation between blood eosinophil counts and FEV1/FVC pre-and post-therapy in Asthma (P = 0.007). Blood neutrophil counts were inversely correlated with FEV1/FVC after treatment (P = 0.032). Night onset in asthma was positively correlated with blood neutrophil counts, while fever was negatively correlated with blood CRP (P = 0.028). Platelet counts >300 × 109/L after treatment were significantly associated with a decline in FEV (<0.001) in patients with asthma. Elevated blood eosinophil count was independently associated with clinical features in asthma. ConclusionsBased on the study's findings, there is a significant decline in FEV1/FVC among individuals with elevated blood eosinophil count, both pre- and post-bronchodilator while there was a independent relationship between blood eosinophil counts and FEV1 pre-and post-therapy in asthma. This suggests that increased levels of eosinophils may independently associated contribute to reduced lung function in asthma patients.

A comprehensive study to determine effect of coronavirus disease on pulmonary function of the affected patients

Background: As the global coronavirus disease-2019 (COVID-19) pandemic continues to unfold, understanding the implications of the disease on post-recovery lung function becomes crucial. This study aimed to investigate the early convalescent phase characteristics of lung function in patients recovering from COVID-19, shedding light on the extent and nature of lung impairments following acute infection. Aims and Objectives: This study aimed to investigate the early convalescent phase characteristics of lung function in patients recovering from COVID-19, shedding light on the extent and nature of lung impairments following acute infection. Materials and Methods: A cross-sectional analysis was conducted on 57 patients who had been diagnosed with COVID-19 and subsequently discharged from the hospital. Comprehensive lung function tests, chest computed tomography scans, and the 6-min walk test were performed approximately 30 days after discharge to assess pulmonary parameters, imaging abnormalities, and exercise tolerance. Results: The study revealed that more than half of the patients exhibited impairments in diffusing capacity (DLCO), respiratory muscle strength, and lung imaging abnormalities during the early convalescent phase. Notably, severe cases demonstrated a significantly higher incidence of DLCO impairment, accompanied by notable reductions in total lung capacity and 6-min walking distances compared to non-severe cases. Interestingly, the severity of illness or residual imaging changes did not consistently correlate with the observed lung function impairments. This observation challenges previous assumptions and underscores the complexity of the relationship between disease severity and post-recovery lung function. Conclusion: In the context of COVID-19 recovery, this study highlights the presence of early convalescent phase impairments in lung function, suggesting that the impact on respiratory health extends beyond the acute phase of infection.

Childhood TB sequel: evaluating respiratory function after treatment for pulmonary tuberculosis in a prospective cohort of Gambian children – a study protocol

Background1.2 million children under 15 years are estimated to have developed tuberculosis (TB) in 2021. 85% of paediatric patients achieve successful treatment outcomes if treated for the first episode of TB. However, despite so-called successful treatment, TB leaves many survivors with permanently destroyed or damaged lungs. Data from prospective paediatric cohorts to establish the burden and evolution of post-TB lung disease (PTLD) are still absent. The Childhood TB Sequel study aims to describe respiratory consequences associated with pulmonary TB in Gambian children, describe the evolution of these sequelae, and determine associated epidemiological risk factors.MethodsWe aim to recruit up to 80 subjects aged 19 years and below who have recently completed treatment for pulmonary TB. Recruitment started in April 2022 and is expected to continue until June 2024. Clinical assessment, chest X-ray, and comprehensive lung function assessment are carried out at treatment completion and again six and 12 months later.DiscussionThe Childhood TB Sequel study will address existing research gaps to enhance our knowledge and understanding of the burden of PTLD in Gambian children. The study will also contribute to formulating a plan for post-TB evaluation and long-term follow-up strategies.Trial registrationClinicalTrials.gov: NCT05325125, April 13, 2022.

Lifelong Lung Sequelae of Prematurity.

The clinical, functional, and structural pattern of chronic lung disease of prematurity has changed enormously in last years, mirroring a better perinatal management and an increasing lung immaturity with the survival of increasingly premature infants. Respiratory symptoms and lung function impairment related to prematurity seem to improve over time, but premature birth increases the likelihood of lung function impairment in late childhood, predisposing to chronic obstructive pulmonary disease (COPD). It is mandatory to identify those individuals born premature who are at risk for developing long-term lung disease through a better awareness of physicians, the use of standardized CT imaging scores, and a more comprehensive periodic lung function evaluation. The aim of this narrative review was to provide a systematic approach to lifelong respiratory symptoms, lung function impairment, and lung structural anomalies in order to better understand the specific role of prematurity on lung health.

Endobronchial resection as a bridge to curative resection in patient with poor preoperative lung function secondary to an airway blocking endobronchial carcinoid tumour

We present a 70-year-old gentleman with chronic cough with haemoptysis found to have left lower zone collapse on imaging. The bronchoscopy showed an endobronchial mass histologically of a non-secreting atypical carcinoid. Poor baseline lung function excluded surgical resection, and instead, he successfully underwent a bronchoscopic debulking procedure which improved his FEV1 to 84% and DLCO 83% predicted. Unfortunately, the tumour regrew, but the calculated percentage predicted postoperative for FEV1 (64%), and DLCO (65%) enabled definitive surgical resection to take place. Surgical resection remains the definite curative option for localised endobronchial atypical carcinoid tumours. Achieving this in proximal endobronchial carcinoid tumour is a challenge. We described an endoscopic tumour debulking procedure as a bridge for curative surgical resection in a patient with an inoperable proximal atypical carcinoid tumour due to poor predicted postoperative lung function. We highlighted the need to assess predicted postoperative lung function with functional and quantitative perfusion methods to aid surgical planning. Debulking the tumour by endoscopy can be used as a conduit to curative surgical resection in bronchial carcinoid tumour. The choice of calculating the percentage predicted values by either or both methods must be individualised based on tumour location and the probability of converting a lobectomy to a pneumonectomy. This precautionary approach could evaluate the postoperative lung function and morbidity and mortality risk if considering a pneumonectomy. Endoscopic debulking can be a successful bridge to a curative surgical resection aided by comprehensive preoperative lung function tests to predict postoperative lung values

Rounded atelectasis after exposure to refractory ceramic fibres (RCF)

BackgroundRefractory Ceramic fibres (RCF) are man-made mineral fibres used in high performance thermal insulation applications. Analogous to asbestos fibres, RCF are respirable, show a pleural drift and can persist in human lung tissue for more than 20 years after exposure. Pleural changes such as localised or diffuse pleural thickening as well as pleural calcification were reported.ResultA 45 years old man worked in high performance thermal insulation applications using refractory ceramic fibres (RCF) for almost 20 years. During a occupational medical prophylaxis to ensure early diagnosis of disorders caused by inhalation of aluminium silicate fibres with X-ray including high-resolution computed tomography (HRCT), bilateral pleural thickening was shown and a pleural calcification next to a rounded atelectasis was detected. Asbestos exposure could be excluded. In pulmonary function test a restrictive lung pattern could be revealed. In work samples scanning electron microscopy (SEM) including energy dispersive X-ray analysis (EDX) classified used fibres as aluminium silicate fibres. X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) showed crystalline as well as amorphous fibres.ConclusionsA comprehensive lung function analysis and in case of restrictive lung disorders additional CT scans are needed in RCF exposed workers in accordance to the guidelines for medical occupational examinations comparable to asbestos exposed workers.

Longitudinal lung function measurements in single lung transplant recipients with chronic lung allograft dysfunction

Phenotyping chronic lung allograft dysfunction (CLAD) in single lung transplant (SLTX) recipients is challenging. The aim of this study was to assess the diagnostic and prognostic value of longitudinal lung function tests in SLTX recipients with CLAD. A total of 295 SLTX recipients were analyzed and stratified according to native lung physiology. In addition to spirometry, measurements of static lung volumes and lung capacities were used to phenotype patients and to assess their prognostic value. Outcome was survival after CLAD onset. Patients with insufficient clinical information were excluded (n = 71). Of 224 lung transplant recipients, 105 (46.9%) developed CLAD. Time to CLAD onset (hazard ratio [HR]: 0.82, 95% CI: 0.74-0.90; p < 0.001), severity of CLAD at onset (HR: 0.97, 95% CI: 0.94-0.99; p = 0.009), and progression after onset of CLAD (HR: 1.03, 95% CI: 1.00-1.05; p = 0.023) were associated with outcome. Phenotypes at onset were bronchiolitis obliterans syndrome (BOS) (59.1%), restrictive allograft syndrome (RAS) (12.4%), mixed phenotype (6.7%), and undefined phenotype (21.9%). Survival estimates differed significantly between phenotypes (p = 0.004), with RAS and mixed phenotype being associated with the worst survival, followed by BOS and undefined phenotype. Finally, a higher hazard for mortality was noticed for RAS (HR: 2.34, 95% CI: 0.99-5.52; p = 0.054) and mixed phenotype (HR: 3.30, 95% CI: 1.20-9.11; p = 0.021) while controlling for time to CLAD onset and severity of CLAD at onset. Phenotyping CLAD in SLTX remains challenging with a high number of patients with an undefined phenotype despite comprehensive lung function testing. However, phenotyping is of prognostic value. Furthermore, early, severe, and progressive CLADs are associated with worse survival.

Clinical and lung function outcomes in a cohort of children with severe asthma

BackgroundUncontrolled severe asthma in children is burdensome and challenging to manage. This study aims to describe outcomes in children with uncontrolled severe asthma managed in a nurse-led severe asthma clinic (SAC).MethodsThis retrospective analysis uses data collected from children referred by a paediatric respiratory specialist to a nurse-led SAC for uncontrolled severe asthma between 2014 and 2019. The pre-clinical assessments included a home visit to assess modifiable factors that could be addressed to improve control. A comprehensive lung function analysis was conducted at each visit. Interventions were personalised and included biologic agents. Statistical analysis was performed using nonparametric, two-tailed Mann-Whitney U-test, the parametric Student’s t-test, or analysis of variance (ANOVA) as appropriate.ResultsTwenty-three children with a median age of 12 years were seen once, and 16 were followed up. Compared to a non-asthmatic (NA) and asthmatic (A) age-matched cohort, children with severe asthma (SA) had a lower FEV1, and FVC% predicted before and after bronchodilator inhalation, and a higher mean Lung Clearance Index [LCI] (10.5 [SA] versus 7.3 [NA] versus 7.6 [A], p = 0.003). Almost 80% of children with SA had an abnormal LCI, and 48% had a reduced FEV1% at the first SAC visit. Asthma control and FEV1% predicted significantly improved at a follow-up visit, while LCI remained abnormal in the majority of children (83%).ConclusionOver time, many children with severe asthma showed improved clinical outcomes and lung function while lung ventilation inhomogeneities persisted. Future appropriately controlled studies are required to determine if a nurse-led multidisciplinary SAC is associated with better outcomes.

Effect of breastfeeding duration on lung function, respiratory symptoms and allergic diseases in school-age children.

A positive effect of breastfeeding on lung function has been demonstrated in cohorts of children with asthma or risk for asthma. We assessed the impact of breastfeeding on lung function and symptoms at the age of 6 years in an unselected, healthy birth cohort. We prospectively studied healthy term infants from the Bern-Basel Infant Lung Development (BILD) cohort from birth up to 6 years. Any breastfeeding was assessed by weekly phone calls during the first year of life. Risk factors (eg, smoking exposure, parental history of allergic conditions, and education) were obtained using standardized questionnaires. The primary outcomes were lung function parameters measured at 6 years of age by spirometry forced expiratory volume in 1 second, body plethysmography (functional residual capacity [FRCpleth ], the total lung capacity [TLCpleth ], and the effective respiratory airway resistance [Reff ]) and fractional exhaled nitric oxide (FeNO). Secondary outcomes included ever wheeze (between birth and 6 years), wheeze in the past 12 months, asthma, presence of allergic conditions, atopic dermatitis, rhinitis, and positive skin prick test at the age of 6 years. In 377 children the mean breastfeeding duration was 36 weeks (SD 14.4). We found no association of breastfeeding duration with obstructive or restrictive lung function and FeNO. After adjustment for confounders, we found no associations of breastfeeding duration with respiratory symptoms or the presence of allergic conditions. This study found no evidence of an association between breastfeeding and comprehensive lung function in unselected healthy children with long-term breastfeeding. Our findings do not support the hypothesis that the duration of breastfeeding has a direct impact on lung function in a healthy population with low asthmatic risk.

Childhood pneumonia, pleurisy and lung function: a cohort study from the first to sixth decade of life

IntroductionAdult spirometry following community-acquired childhood pneumonia has variably been reported as showing obstructive or non-obstructive deficits. We analysed associations between doctor-diagnosed childhood pneumonia/pleurisy and more comprehensive lung function in a...

Investigating the relationships among lung function variables in chronic obstructive pulmonary disease in men.

BackgroundIn patients with chronic obstructive pulmonary disease (COPD), the independent contributions of individual lung function variables to outcomes may be lower when they are modelled together if they are collinear. In addition, lung volume measurements may not be necessary after spirometry data have been obtained. However, these hypotheses depend on whether forced vital capacity (FVC) can predict total lung capacity (TLC). Moreover, the definitions of hyperinflation and air trapping according to lung function variables overlap and need be clarified. Therefore, the aim of this study was to evaluate the relationships among various lung function parameters to elucidate these issues.MethodsDemographic data and 26 parameters of full lung function were measured in 94 men with COPD and analyzed using factor and correlation analyses.ResultsFactor analysis revealed five latent factors. Inspiratory capacity (IC)/TLC and residual volume (RV)/TLC were most strongly correlated with all other lung volumes. IC/TLC, RV/TLC, and functional residual capacity (FRC)/TLC were collinear and were potential markers of air trapping, whereas TLC%, FRC%, and RV% were collinear and were potential markers of hyperinflation. RV/TLC >0.4 (or IC/TLC <0.4) was comparable with the ratio of forced expiratory volume in one second (FEV1) and FVC <0.7. FVC% and FEV1% were poorly correlated with TLC%. The correlation study showed that TLC%, RV/TLC, and FEV1% could be used to represent individual latent factors for hyperinflation, air trapping, inspiration, expiration, and obstruction. Combined with diffusion capacity%, these four factors could be used to represent comprehensive lung function.ConclusionsThis study identified collinear relationships among individual lung function variables and thus selecting variables with close relationships for correlation studies should be performed with caution. This study also differentiated variables for air trapping and lung hyperinflation. Lung volume measurements are still required even when spirometry data are available. Four out of 26 lung function variables from individual latent factors could be used to concisely represent lung function.

Long-term medical and psychosocial outcomes in congenital diaphragmatic hernia survivors

ObjectiveSurvival rates for congenital diaphragmatic hernia (CDH) are increasing. The long-term outcomes of CDH survivors were compared with a healthy control group to assess the morbidity for guidance of antenatal...

Observational cross-sectional study on Symptoms Associated to Moisture DAmage at Workplace: the SAMDAW study protocol

IntroductionMoisture damage (MD) exposure at work has been shown to increase the risk of new onset asthma and exacerbation of asthma. However, most of the studies in this field have...

Faster oxygen uptake, heart rate, and ventilatory kinetics in stepping compared with cycle ergometry in patients with COPD during moderate-intensity exercise.

Step tests are a stressful and feasible cost-effective modality to evaluate aerobic performance. However, the eccentric in addition to concentric muscle contractions of the legs on stepping emerge as a potential speeding factor for cardioventilatory and metabolic adjustments towards a steady-state, since eccentric contractions would prompt an earlier and stronger mechanoreceptor activation, as well as higher heart rate/cardiac output adjustments to the same metabolic demand. Moreover, shorter tests are ideal for exercise-limited subjects. Nine subjects with chronic obstructive pulmonary disease were invited to participate in comprehensive lung function tests and constant work tests performed on different days at a 90% gas exchange threshold for 6 min, in single-step tests or cycle ergometry. After careful monoexponential regression modelling, statistically relevant faster phase II time constants for oxygen uptake (45 ± 18 s vs 53 ± 17 s, p = 0.017) and minute ventilation (61 ± 13 s vs 74 ± 17 s, p = 0.027) were observed in the 6-min step tests compared with cycle ergometry, respectively. Despite an absence of heart rate time constant difference (43 ± 20 s vs 69 ± 46 s, p = 0.167), there was a significantly faster rate constant toward a steady state for heart rate (p = 0.02). In addition, 4-min compared with 6-min analysis presented similar results (p > 0.05), providing an appropriate steady-state. We conclude that step tests might elicit faster time constants compared with cycle ergometry, at the same average metabolic level, and 4-min analysis has similar mean errors compared with 6-min analysis within an acceptable range. New studies, comprising mechanisms and detailed physiological backgrounds, are necessary.

Comprehensive Lung Function Assessment Does not Allow to Infer Response to Pulmonary Rehabilitation in Patients with COPD.

The degree of lung function is frequently used as referral criterion for pulmonary rehabilitation. The efficacy of pulmonary rehabilitation was assessed in 518 chronic obstructive pulmonary disease (COPD) patients, after clustering based on a comprehensive pre-rehabilitation lung function assessment. Mean improvements in dyspnea, exercise performance, health status, mood status and problematic activities of daily life after pulmonary rehabilitation were mostly comparable between the seven clusters, despite significant differences in the degree of lung function. The current study demonstrates no significant relationship between the seven lung-function-based clusters and response to pulmonary rehabilitation. Therefore, baseline lung function cannot be used to identify those who will respond well to pulmonary rehabilitation, and moreover, cannot be used as a criterion for referral to pulmonary rehabilitation in patients with COPD.

Is Inspiratory Muscle Weakness a Determinant of Endurance Exercise Tolerance During NIV-Supported Exercise in Patients With COPD?

Previous research has reported that inspiratory muscle weakness is critical to decreased exercise tolerance and exercise tolerance improves with 10 cmH2O pressure support ventilation in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to evaluate the effects of proportional assist ventilation (PAV) and continuous positive airway pressure (CPAP) compared with sham on exercise tolerance in patients with and without inspiratory muscle weakness. In a prospective design, 12 of 54 patients were eligible after clinical and comprehensive lung function evaluation, including maximum inspiratory pressure (MIP) measurement. Using baseline measures, participants were divided into 2 age-matched groups that differed in regard to MIP (Group 1, MIP <60 cmH2O, and Group 2, MIP ≥60 cmH2O). Each participant performed 3 constant work rate tests with noninvasive support (PAV, CPAP, sham) in random order on different days at 80% of maximal incremental power. During the endurance tests, heart rate, peripheral oxygen saturation (SpO2), dyspnea perception scale, and exercise tolerance were measured. There were no significant differences between groups for heart rate, SpO2, dyspnea perception, or exercise tolerance during PAV, CPAP, or sham-supported exercise (P > .05 for all). In this small representative group of patients with COPD, inspiratory muscle weakness was not a determining factor of performance during CPAP or PAV-supported aerobic exercise.

Left ventricular diastolic dysfunction and exertional ventilatory inefficiency in COPD.

Left ventricular diastolic dysfunction (LVDD) is highly prevalent in COPD and conflicting results have emerged regarding the consequences on exercise capacity in the 6MWT. We sought to examine the ventilatory efficiency and variability metrics as the primary endpoint and aerobic capacity (V'O2) as the secondary endpoint. Forty subjects were included and submitted to comprehensive lung function tests, detailed pulsed-Doppler echocardiography, and cardiopulmonary exercise testing. Four subjects were excluded due to concomitant cardiac disease and two owing to COPD exacerbation. Seventeen COPD/LVDD+ and seventeen COPD/LVDD-individuals were closely matched for baseline characteristics. Throughout the exercise, there was no difference between-groups for primary (V'E/V'CO2slope and V'E/V'CO2nadir, p > 0.05 for both) or secondary endpoints (V'O2peak%pred, p>0.05). Ventilatory variability remained unchanged. However, after very well age- and sex-matched subgroup analysis, five-moderate and three-mild COPD/LVDD+subjects with elevated left ventricular filling pressure (E/e'>13, n=8), presented a downward-shifted V'E/V'CO2slope (25.7 ± 5.1 vs 33.4 ± 7.1, p = 0.031) and V'E/V'CO2nadir reduction (29.7 ± 3.9 vs 36.3 ± 7.2, p = 0.042) besides significantly better V'O2peak%pred (92.1 ± 21.6% vs 75.8 ± 13.1%, p = 0.045) compared to 8 COPD/LVDD-controls. Ventilatory variability remained once again unchanged. COPD/LVDD overlap is not associated with worse exercise tolerance and/or wasted ventilation in excess compared to controls, even when suspected for elevated left ventricular filling pressure. Further studies are warranted to study specifically if augmented pulmonary blood transit time can allow better gas-exchange, thus preserving exercise capacity under specific conditions in COPD patients without heart failure.

The respiratory physiome: Clustering based on a comprehensive lung function assessment in patients with COPD.

BackgroundWhile spirometry and particularly airflow limitation is still considered as an important tool in therapeutic decision making, it poorly reflects the heterogeneity of respiratory impairment in chronic obstructive pulmonary disease (COPD). The aims of this study were to identify pathophysiological clusters in COPD based on an integrated set of standard lung function attributes and to investigate whether these clusters can predict patient-related outcomes and differ in clinical characteristics.MethodsClinically stable COPD patients referred for pulmonary rehabilitation underwent an integrated assessment including clinical characteristics, dyspnea score, exercise performance, mood and health status, and lung function measurements (post-bronchodilator spirometry, body plethysmography, diffusing capacity, mouth pressures and arterial blood gases). Self-organizing maps were used to generate lung function based clusters.ResultsClustering of lung function attributes of 518 patients with mild to very severe COPD identified seven different lung function clusters. Cluster 1 includes patients with better lung function attributes compared to the other clusters. Airflow limitation is attenuated in clusters 1 to 4 but more pronounced in clusters 5 to 7. Static hyperinflation is more dominant in clusters 5 to 7. A different pattern occurs for carbon monoxide diffusing capacity, mouth pressures and for arterial blood gases. Related to the different lung function profiles, clusters 1 and 4 demonstrate the best functional performance and health status while this is worst for clusters 6 and 7. All clusters show differences in dyspnea score, proportion of men/women, age, number of exacerbations and hospitalizations, proportion of patients using long-term oxygen and number of comorbidities.ConclusionBased on an integrated assessment of lung function variables, seven pathophysiological clusters can be identified in COPD patients. These clusters poorly predict functional performance and health status.