FVC Measurements Research Articles

“Bubbly lung”, a honeycombing variant with more favorable outcome

BackgroundAlthough radiologic honeycombing is generally associated with progressive fibrosis and a dismal prognosis, some patients display an unexpectedly indolent clinical course. We aimed to assess for variants of honeycombing associated with a more favorable prognosis. MethodsA computer-assisted search was conducted to identify patients encountered at Mayo Clinic from 1998 to 2022 who had undergone chest CT that manifested exuberant honeycombing. Medical records and chest imaging studies were reviewed to identify clinical, pulmonary function and radiologic features. ResultsAmong 136 patients with exuberant honeycombing, 23 patients were identified with CT features of what we termed “bubbly lung” characterized by extensive macrocystic fibrosis; 17 (74%) were female with a median age of 71 years (range, 32–88) at baseline. Underlying diagnoses were ANCA associated vasculitis (22%), overlap CTD (22%), rheumatoid arthritis (17%), IPF (17%), IPAF (9%), systemic sclerosis (4%), undifferentiated CTD (4%), and dermatomyositis (4%). Median FVC was 78% predicted (range 35–112), median DLco was 41% predicted (range 10–92), and median TLC was 73% predicted (range 57–116). Serial FVC measurements were available for 19 (83%) patients with a median interval of 4.7 years (range: 0.4–20); median FVC change per year was 23 ml (range −279 to +232) and median FVC % predicted change per year was 0.00% (range −3.20 to +6.79%). The median survival was 7.1 years, 5-year survival was 76% (95% CI: 58%–100%) and 10-year survival was 48%. Conclusions“Bubbly lung” is a variant of exuberant honeycombing that is associated with better-than-expected outcome and FVC decline per year.

Unveiling the Respiratory Muscle Strength in Duchenne Muscular Dystrophy: The Impact of Nutrition and Thoracic Deformities, Beyond Spirometry.

Duchenne muscular dystrophy (DMD) is the most prevalent progressive muscular dystrophy, and the guidelines recommend the regular assessment of respiratory muscle function. This study aimed to assess the relationship between maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP) and sniff nasal inspiratory pressure (SNIP) measurements and upright-supine spirometry parameters in children with DMD, the predictability of upright-supine spirometry in terms of diaphragm involvement, and the impact of nutrition on muscle strength. This prospective cross-sectional study examined patients with DMD by comparing upright and supine FVC, MIP, MEP, and SNIP measurements. The effects of the ambulatory status, kyphoscoliosis, chest deformity, and low BMI on respiratory parameters were investigated. Forty-four patients were included in the study. The mean patient age was 10.8 ± 2.9 years. Twenty-five patients were ambulatory. A significant decrease in FVC, FEV1, and FEF25-75 values was detected in the supine position in both ambulatory and non-ambulatory patients (p < 0.05). All patients had low MIP, MEP, and SNIP measurements (less than 60 cm H2O). MIP, MEP, and SNIP values were significantly lower in patients with a low BMI than in those without (p < 0.05). To accurately assess respiratory muscle strength, supine FVC should be combined with upright FVC, MIP, MEP, and SNIP measurements. It is crucial to regularly screen patients for nutrition, as this can significantly affect respiratory muscle function during pulmonology follow-up.

Ant-waist surgery adversely affects lung function: a cross-sectional study.

Body contouring surgery for the removal of the 11th and 12th ribs is undertaken for aesthetic appeal in female and transgender populations. The potential adverse effects of the surgery on lung function and respiratory muscle strength have not been previously studied. Therefore, this study aimed to determine the effects of 'Ant-waist' surgery on lung function and respiratory muscle strength in individuals who had undergone surgery. This was a cross-sectional study with two groups, an Anti-waist group who had undergone surgery and an age and gender matched control group. Participants performed lung function tests to determine measurements of FEV1, FVC, FEV1/FVC, PEF, MIP, and MEP. Independent t-tests were performed to determine between-group differences in outcomes and Pearson's correlation coefficients determined the relationship between lung function and respiratory muscle strength, and number of years since surgery. There was a significant between-group difference in FEV1 (-0.83; 95%CI -1.30, -0.36; p<0.001), FEV1%pred. (-34.91; 95%CI -48.92, -20.90; p<0.001), FVC%pred. (-22.73; 95%CI -32.84, -12.62; p<0.001), PEF%pred. (-44.18; 95%CI -61.52, -26.84; p<0.001) and MEP (-68.27; -102.48, -34.07; p<0.001). There were significantly large, negative correlations (r>0.5) between the number of years after surgery and FEV1 (p=0.002), FEV1%pred. (p=0.0001); and PEF%pred. (p=0.032). This study has identified that aesthetic surgery for the removal of ribs 11 and 12 had a significant adverse effect on lung function and respiratory muscle strength in Jordanian females. The potential adverse effects should be carefully explained by surgeons to patients considering the surgery.

Assessing the quality of forced vital capacity measurement in patients with systemic sclerosis

IntroductionForced vital capacity (FVC) is an important tool for monitoring lung functions in patients with systemic sclerosis (SSc). However, several disease manifestations may influence the quality of FVC test in SSc. We aimed to assess the quality of FVC measurements according to current guidelines in patients with SSc and determine the factors that may affect results. MethodIn this cross-sectional study, SSc patients and age/sex matched controls underwent spirometry. Quality of FVC measurements were graded according to updated American Thoracic Society (ATS) and European Respiratory Society (ERS) guidelines. Demographics, clinical features and parameters that may affect FVC test quality were compared between SSc patients with high and low quality FVC test. Results98 SSc patients (90 female) and 100 controls were included. The rate of high quality FVC measurement in SSc patients was significantly lower in SSc patients compared to controls. (80 % vs 60.2 % p = 0.002). Among SSc patients; diffuse disease, ILD, anti-topoisomerase 1 antibody positivity, immunosuppressive use, flexion contractures of hands, reduced mouth opening and decreased chest expansion were more frequent in patients with low quality FVC (p < 0.05 for all). Patients with muscle weakness and medium/high risk of malnutrition were also numerically higher in low quality FVC group. Presence of more than one condition that may affect FVC quality was significantly higher among patients with low quality FVC. ConclusionA significant percent of SSc patients had low quality FVC measurement. Physicians should be aware of this point while interpreting FVC test results especially in SSc patients with more than one condition that may affect the quality of the test.

Disease diagnosis and severity classification in pulmonary fibrosis using carbonyl volatile organic compounds in exhaled breath

BackgroundPathophysiological conditions underlying pulmonary fibrosis remain poorly understood. Exhaled breath volatile organic compounds (VOCs) have shown promise for lung disease diagnosis and classification. In particular, carbonyls are a byproduct of oxidative stress, associated with fibrosis in the lungs. To explore the potential of exhaled carbonyl VOCs to reflect underlying pathophysiological conditions in pulmonary fibrosis, this proof-of-concept study tested the hypothesis that volatile and low abundance carbonyl compounds could be linked to diagnosis and associated disease severity. MethodsExhaled breath samples were collected from outpatients with a diagnosis of Idiopathic Pulmonary Fibrosis (IPF) or Connective Tissue related Interstitial Lung Disease (CTD-ILD) with stable lung function for 3 months before enrollment, as measured by pulmonary function testing (PFT) DLCO (%), FVC (%) and FEV1 (%). A novel microreactor was used to capture carbonyl compounds in the breath as direct output products. A machine learning workflow was implemented with the captured carbonyl compounds as input features for classification of diagnosis and disease severity based on PFT (DLCO and FVC normal/mild vs. moderate/severe; FEV1 normal/mild/moderate vs. moderately severe/severe). ResultsThe proposed approach classified diagnosis with AUROC=0.877 ± 0.047 in the validation subsets. The AUROC was 0.820 ± 0.064, 0.898 ± 0.040, and 0.873 ± 0.051 for disease severity based on DLCO, FEV1, and FVC measurements, respectively. Eleven key carbonyl VOCs were identified with the potential to differentiate diagnosis and to classify severity. ConclusionsExhaled breath carbonyl compounds can be linked to pulmonary function and fibrotic ILD diagnosis, moving towards improved pathophysiological understanding of pulmonary fibrosis.

Trend and heterogeneity in forced vital capacity among Chinese students during 1985–2019: results from Chinese National Survey on Students’ Constitution and Health

BackgroundForced vital capacity (FVC) reflects respiratory health, but the long-term trend and heterogeneity in FVC of Chinese students were understudied.MethodsData were from Chinese National Survey on Students’ Constitution and Health 1985–2019. Super Imposition by Translation and Rotation model was used to draw FVC growth curves. Sex-, region-, and nationality-heterogeneity in FVC was evaluated. Spearman correlation and generalized additive model was used to reveal influencing factors for FVC.ResultsCompared to 1985, age at peak FVC velocity was 1.09, 3.17, 0.74, and 1.87 years earlier for urban male, urban female, rural male, and rural female in 2019, respectively. Peak FVC velocity first decreased and then increased during 1985–2019, only male rebounded to larger than 1985 level. FVC declined from 1985 to 2005 and then raised. Males consistently had higher FVC than females, with disparities increasing in the 13–15 age group. Urban students also had higher FVC than rural students. In 2019, FVC difference between 30 Chinese provinces and the national average showed four scenarios: consistently above national average; less than national average until age 18, then above; greater than national average until age 18, then this advantage reversed; less than national average in almost all the age. Most Chinese ethnic minority students had lower FVC levels compared to Han students. Spearman correlation and generalized additive model showed that age, sex, and height were the leading influencing factors of FVC, followed by socioeconomic and environmental factors.ConclusionsChinese students experienced advanced FVC spurt, and there was sex-, region- and nationality-heterogeneity in FVC. Routine measurement of FVC is necessary in less developed areas of China.

Clinical Characteristics and Disease Course of Fibrosing Interstitial Lung Disease Patients in a Real-World Setting

Background and Objectives: This single-center retrospective study was conducted to describe clinical characteristics and the disease course of patients with interstitial lung diseases (ILD). Materials and Methods: The study included adult patients with fibrosing ILD (IPF, non-IPF fibrosing ILD (F-ILD), and non-IPF progressive pulmonary fibrosis (PPF)) treated between 2014 and 2017. Patients were followed annually from the first visit until the end of the study period in 2019. Data were collected from the Turku University Hospital data lake and analyzed using descriptive statistics. Results: 591 patients formed the patient cohort: 110 had IPF, 194 F-ILD, 142 PPF, and the remaining 145 patients were uncertain, F-ILD-U, whose disease progression nature could not be confirmed by FVC measurements. There were more males in each patient group and median age of the groups was similar, although there were younger patients in the PPF, F-ILD, and F-ILD-U groups. PPF patients had more UIP pattern than F-ILD patients. Exposure-related ILDs were clearly the most found ILD diagnoses for both PPF and F-ILD, followed by unclassifiable IIP. Baseline FVC % predicted reduction in every group was moderate. Half of the patients in each group had comorbidities, and the most common were cardiovascular diseases, diabetes, sleep apnea, and chronic lower respiratory diseases; F-ILD-U patients had malignant diseases as well. IPF patients had less medications than the other groups. Glucocorticoids were the most used medication in all patient groups. More PPF and F-ILD patients remained in the follow-up than IPF and F-ILD-U patients. Similarly, mortality of F-ILD-U was the highest, followed by IPF. Evolvement of lung function, oxygen use, and number of acute hospitalizations were similar for IPF and PPF patients whereas the corresponding results were always better for F-ILD patients. Conclusions: The disease course of IPF and PPF was similar, and PPF patient amount exceeded the amount of IPF patients.

Investigation of the effect of basic swimming education course on some respiratory parameters of university students

In this study, the effect of 12-week basic swimming training of sports science students on some respiratory parameters was determined. In the 2nd, 3rd and 4th grades of Gümüşhane University School of Physical Education and Sports, 64 (111) male students who did not take swimming lessons and 47 who took swimming lessons participated voluntarily. The experimental group was given breath work for 12 weeks during the course content and for 10 minutes at the end. Measurements were taken from the students twice before and after the 12-week education. SPSS 25.0 program was used in the analysis of the data collected within the scope of the research. Independent comparison of age, height and body weight measurements of the athletes in the experimental and control groups. Samples T Test was used. In the comparison of time, group, group x time changes of FVC, MVV, VC and FEV1 measurements, Repeated Measures ANOVA analysis was used. Statistical significance level was taken as (p&lt;0.05). As a result of the research, a significant result could not be reached in FVC and FEV1 values between Tests, Groups and Group x time intervals, whereas VC was only between tests. However, statistically significant differences were found between MVV and VC Tests, Groups and Group x Time values. In short, it has been shown that students who take swimming lessons have statistically higher lung volumes than students who do not take the lesson. However, swimming activity can be recommended to increase respiratory efficiency of university students.

Adaptiveness of RGB-image derived algorithms in the measurement of fractional vegetation coverage

BackgroundFractional vegetation coverage (FVC) is a crucial parameter in determining vegetation structure. Automatic measurement of FVC using digital images captured by mobile smart devices is a potential direction for future research on field survey methods in plant ecology, and this algorithm is crucial for accurate FVC measurement. However, there is a lack of insight into the influence of illumination on the accuracy of FVC measurements. Therefore, the main objective of this research is to assess the adaptiveness and performance of different algorithms under varying light conditions for FVC measurements and to deepen our understanding of the influence of illumination on FVC measurement.Methods and resultsBased on a literature survey, we selected four algorithms that have been reported to have high accuracy in automatic FVC measurements. The first algorithm (Fun01) identifies green plants based on the combination of R/G, B/G, and ExG (R, G, and B are the actual pixel digital numbers from the images based on each RGB channel, ExG is the abbreviation of the Excess Green index), the second algorithm (Fun02) is a decision tree that uses color properties to discriminate plants from the background, the third algorithm (Fun03) uses ExG-ExR (ExR is the abbreviation of the Excess Red index) to recognize plants in the image, and the fourth algorithm (Fun04) uses ExG and O{text{tsu}} to separate the plants from the background. Otsu is an algorithm used to determine a threshold to transform the image into a binary image for the vegetation and background. We measured the FVC of several surveyed quadrats using these four algorithms under three scenarios, namely overcast sky, solar forenoon, and solar noon. FVC values obtained using the Photoshop-assisted manual identification method were used as a reference to assess the accuracy of the four algorithms selected. Results indicate that under the overcast sky scenario, Fun01 was more accurate than the other algorithms and the MAPE (mean absolute percentage error), BIAS, relBIAS (relative BIAS), RMSE (root mean square error), and relRMSE (relative RMSE) are 8.68%, 1.3, 3.97, 3.13, and 12.33%, respectively. Under the scenario of the solar forenoon, Fun02 (decision tree) was more accurate than other algorithms, and the MAPE, BIAS, relBIAS, RMSE, and relRMSE are 22.70%, − 2.86, − 7.70, 5.00, and 41.23%. Under the solar noon scenario, Fun02 was also more accurate than the other algorithms, and the MAPE, BIAS, relBIAS, RMSE, and relRMSE are 20.60%, − 6.39, − 20.67, 7.30, and 24.49%, respectively.ConclusionsGiven that each algorithm has its own optimal application scenario, among the four algorithms selected, Fun01 (the combination of R/G, B/G, and ExG) can be recommended for measuring FVC on cloudy days. Fun02 (decision tree) is more suitable for measuring the FVC on sunny days. However, it considerably underestimates the FVC in most cases. We expect the findings of this study to serve as a useful reference for automatic vegetation cover measurements.

Modification of the ALSFRS-R for Utilization in Individuals Not Using Noninvasive Ventilation.

The Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) is widely employed in assessing functional decline in individuals with amyotrophic lateral sclerosis (ALS). A limitation of the scale is that item 12 does not directly evaluate worsening respiratory failure in ALS but rather the management thereof as a surrogate marker. We propose an alternative scale to assess respiratory function in ALS individuals who do not use noninvasive ventilation (NIV). 85 participants were included in the study. ALSFRS-R scores were calculated and FVC measured at each clinic visit. Additional questions were asked regarding the presence of nocturnal hypoventilation symptoms, including (1) early-morning headaches, (2) excessive daytime somnolence, (3) poor concentration, and (4) decrease in appetite. A nocturnal hypoventilation item was developed using these questions in participants not using NIV. Internal consistency and validity were calculated using the nocturnal hypoventilation item as substitute for the existing item 12. The ALSFRS-R was modified by adding the alternative item 12 and named ALSFRS-Revised Modified (ALSFRS-RM). The ALSFRS-RM has a strong internal consistency and validity, which was calculated using Cronbach alpha and factor analysis. A Spearman correlation of 0.34 was calculated between the measured FVC and the nocturnal hypoventilation item score. In addition, a nocturnal hypoventilation item score of ≤ 3 corresponds to an FVC of ≤ 65%, with the upper 95% CI < 80%. Our results suggest that the addition of an alternative item 12 to the existing ALSFRS-R may be a viable option for use in individuals not receiving ventilatory support. The new nocturnal hypoventilation item may also be a reliable indicator of respiratory decline that may remove the need for FVC measurement prior to introducing NIV.

Clinical Validation of the Spirohome Clinic Ultrasonic Spirometer in Child and Adolescent Patients.

BackgroundSpirometers are critical devices that reveal the respiratory dynamics caused by respiratory problems and their severity and facilitate their diagnosis and follow-up. Hand-held spirometers have emerged relatively recently and offer several advantages over conventional desktop systems. There remains, however, a need for reassurance of high-quality spirometry testing with next-generation portable spirometers that connect over Bluetooth® to smart device applications. In this study, we examine the accuracy and repeatability of lung function measurements of a novel hand-held ultrasonic spirometer, the Spirohome Clinic and compare its clinical performance to a reference device, the EasyOne Air.MethodsBenchtop validation of the spirometers was conducted using a lung simulator device according to ATS/ERS guidelines and the ISO 26782 standard waveforms. Subsequently, 48 volunteers (pediatric patients between 6 and 11 years of age and adolescent patients between 12 and 18 years of age) performed spirometry with both the Spirohome Clinic and the EasyOne Air spirometer during their clinic visits. Spirometric data including repeated FEV1, FVC, FEV6, FEF25-75, and PEF measurements were collected.ResultsBoth the Spirohome Clinic and the EasyOne Air successfully passed requirements for accuracy stated in relevant guidelines and standards for spirometry. The only statistically significant (p<0.05) difference was for FVC measurement accuracy. Clinical comparisons revealed strong correlation between spirometers in the measurement of key pulmonary function parameters including FEV1 and FVC with a Pearson's correlation coefficient of 0.99. Bland–Altman plots showed good agreement between mean differences of FEV1 and FVC with the majority measurements remaining between the limits of 95% agreement for both the entire patient cohort and also in age and gender subsets.ConclusionThe present study demonstrated that the Spirohome Clinic spirometer conforms to ATS/ERS performance requirements and validates the clinical comparability of its measurement accuracy and repeatability to the EasyOne Air. These findings support the indicated use of the Spirohome Clinic for high-quality lung function testing in clinical settings.

Pulmonary Dysfunction Augmenting Bacterial Aerosols in Leather Tanneries of Punjab, Pakistan.

BackgroundParticulate matter–associated microbes in the workplace are a burning issue in occupational toxicology. Studies have reported on respiratory infections among tannery cohorts. This study uniquely presents measurements of airborne bacterial concentrations associated with varied particulate-matter sizes, their exposure, and consequent severity in occupational respiratory problems, all for different microenvironments within leather tanneries.MethodsAnalyses included molecular identification of isolates, computation of mass median aerodynamic diameter of aerosols, tannery process–exposure dose (TPED) to bacterial aerosols, and spirometry and symptom assessment of impaired pulmonary function.ResultsThe highest bacterial concentrations were for rawhide treatment and finishing units, showing 3.6×103 and 3.7×103 CFU/m3, respectively. Identified bacterial species included Ochrobactrum pseudogrignonense, Neisseria bacilliformis, Enterobacter cloacae, Alcaligenes faecalis, Klebsiella pneumoniae, and Corynebacterium spp. Maximum and minimum values of mass median aerodynamic diameter were 8.3 µm and 0.65 µm for buffing and snuffing and production units, respectively. The highest TPED was 1,516.9 CFU/kg for finishing units. Respiratory symptoms in order of incidence were dyspnea > phlegm > cough > wheezing and tachypnea (equivalent). Bronchodilator measurements of FEV1, FVC, and PEF represent decline in lung function. Of 26 patients identified with COPD, most were working in rawhide treatment.ConclusionWe conclude that exposure–infection synergy is also a cause of pulmonary ailments and COPD development, rather than the better-known exposure–smoking synergy.

EPS1.06 A retrospective audit of home-based spirometry quality in a large UK adult cystic fibrosis centre

Objectives: Spirometry measurement is the gold standard for assessing disease severity in cystic fibrosis (CF). Poor-quality spirometry tests can result in inaccurate measurement of FEV1 and FVC. Manchester Adult CF Centre has transformed from hospital to home-based spirometry testing during COVID-19. Unlike hospital-based spirometry, home-based spirometry relies entirely on the subject to obtain good quality spirometry. Therefore, we sought to ascertain the quality of home-based spirometry and the test errors in our patients. Methods: A convenience sample of adults with CF attending Manchester Adult CF Centre were provided with a NuvoAir home-based spirometer to perform routine lung function between March–October 2020. NuvoAir respiratory platform consists of a mobile phone application, Bluetooth spirometer and an online results portal. The spirometer also provides feedback to patients’ spirometry quality. Initial patient set-up was performed in-hospital or virtually with a member of the CF clinical team. All patient sessions were included irrespective of quality of spirometry test session. Acceptability and repeatability criteria were applied as per NuvoAir software in line with ATS/ERS guidelines, along with assigning a quality grading A–Faccording to ATS/ERS standardised pulmonary function report criteria at time of testing. Results: 66 CF patients (32 female) mean age 31.3 (18–55) performed 343 spirometry sessions totaling 1,041 individual spirometry tests with a NuvoAir device were graded as follows: Grade A = 30.3%, Grade B = 36.2%, Grade C = 3.5%, Grade D = 2.6%, Grade E = 16.6%, Grade F = 10.8%. Further analysis of all 1,041 tests for common errors indicated BX – Back extrapolation 2%, TP- Time to Peak (slow start) 14.6%, CO – Cough 1.4%, ET – Early termination 0.5%, CE – Cessation or glottic closure 12.9%. Overall, general tests A–C considered usable was 70%. Conclusion: The results show good-quality standards can be achieved through home-based spirometry.

Characteristics Associated with Accelerated Lung Function Decline in a Primary Care Population with Chronic Obstructive Pulmonary Disease.

BackgroundEstimates for lung function decline in chronic obstructive pulmonary disease (COPD) have differed by study setting and have not been described in a UK primary care population.PurposeTo describe rates of FEV1 and FVC decline in COPD and investigate characteristics associated with accelerated decline.Patients and MethodsCurrent/ex-smoking COPD patients (35 years+) who had at least 2 FEV1 or FVC measurements ≥6 months apart were included using Clinical Practice Research Datalink. Patients were followed up for a maximum of 13 years. Accelerated rate of lung function decline was defined as the fastest quartile of decline using mixed linear regression, and association with baseline characteristics was investigated using logistic regression.ResultsA total of 72,683 and 50,649 COPD patients had at least 2 FEV1 or FVC measurements, respectively. Median rates of FEV1 and FVC changes or decline were −18.1mL/year (IQR: −31.6 to −6.0) and −22.7mL/year (IQR: −39.9 to −6.7), respectively. Older age, high socioeconomic status, being underweight, high mMRC dyspnoea and frequent AECOPD or severe AECOPD were associated with an accelerated rate of FEV1 and FVC decline. Current smoking, mild airflow obstruction and inhaled corticosteroid treatment were additionally associated with accelerated FEV1 decline whilst women, sputum production and severe airflow obstruction were associated with accelerated FVC decline.ConclusionRate of FEV1 and FVC decline was similar and showed similar heterogeneity. Whilst FEV1 and FVC shared associations with baseline characteristics, a few differences highlighted the importance of both lung function measures in COPD progression. We identified important characteristics that should be monitored for disease progression.

Stratification of long-term outcome in stable idiopathic pulmonary fibrosis by combining longitudinal computed tomography and forced vital capacity.

To test HRCT with either visual or quantitative analysis in both short-term and long-term follow-up of stable IPF against long-term (transplant-free) survival, beyond 2years of disease stability. Fifty-eight IPF patients had FVC measurements and HRCTs at baseline (HRCT0), 10-14months (HRCT1) and 22-26months (HRCT2). Visual scoring, CALIPER quantitative analysis of HRCT measures, and their deltas were evaluated against combined all-cause mortality and lung transplantation by adjusted Cox proportional hazard models at each time interval. At HRCT1, a ≥ 20% relative increase in CALIPER-total lung fibrosis yielded the highest radiological association with outcome (C-statistic 0.62). Moreover, the model combining FVC% drop ≥ 10% and ≥ 20% relative increase of CALIPER-total lung fibrosis improved the stratification of outcome (C-statistic 0.69, high-risk category HR 12.1; landmark analysis at HRCT1 C-statistic 0.66, HR 14.9 and at HRCT2 C-statistic 0.61, HR 21.8). Likewise, at HRCT2, the model combining FVC% decrease trend and ≥ 20% relative increase of CALIPER-pulmonary vessel-related volume (VRS) improved the stratification of outcome (C-statistic 0.65, HR 11.0; landmark analysis at HRCT1 C-statistic 0.62, HR 13.8 and at HRCT2 C-statistic 0.58, HR 12.6). A less robust stratification of outcome distinction was also demonstrated with the categorical visual scoring of disease change. Annual combined CALIPER -FVC changes showed the greatest stratification of long-term outcome in stable IPF patients, beyond 2years. • Longitudinal high-resolution computed tomography (HRCT) data is more helpful than baseline HRCT alone for stratification of long-term outcome in IPF. • HRCT changes by visual or quantitative analysis can be added with benefit to the current spirometric reference standard to improve stratification of long-term outcome in IPF. • HRCT follow-up at 12-14months is more helpful than HRCT follow-up at 23-26months in clinically stable subjects with IPF.

Assessment of interstitial lung disease in systemic sclerosis using the quantitative CT algorithm CALIPER.

Interstitial lung disease (ILD) remains a major cause of morbidity and mortality in systemic sclerosis (SSc). Study aim is to characterize and quantify SSc-ILD by using Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER). Secondly, our objective is to evaluate which radiological pattern is predictive of lung function decline at 12months follow-up. In the prospective study (IRB 5435), 66 SSc patients underwent high-resolution computerized tomography (HRCT) at baseline. HRCT was performed according to standard protocol using a CT 64GE light speed VCT power scanner. CALIPER classified lung parenchyma on volume units. Every volume unit was classified into radiological parenchymal patterns (honeycombing, reticular and ground glass). Pulmonary function tests (PFTs) were performed at baseline and after 12months of follow-up. Cigarette smoking and other lung diseases unrelated to SSc are exclusion criteria. CALIPER analysis showed normal lung parenchyma 87.4± 9.8%, ground glass 2.8± 5.3%, reticular 4 ± 5.7%, and honeycombing 1 ± 1%. In multiple regression analysis, FEV1 (p < 0.0001), FVC (p = 0.001), and DLCO (p < 0.0001) measurements at baseline showed a negative correlation with the reticular pattern percentage. At follow-up, DLCO reduction showed a positive correlation (p < 0.001) with the percentage of ground glass pattern (r = 0.33, beta coefficient = 0.51). In the ROC curve analysis, ground glass score is a good predictor (0.75, p = 0.009; 95% CI 0.59-0.91) of DLCO worsening, defined as a decrease of more than 10% of DLCO. Using a cutoff ≥ 4.5 for ground glass score, the RR for DLCO worsening is 6.8 (p < 0.01; 95% CI 1.6-29.2). The results of this study show that CALIPER is useful not only for quantifying lung damage but also for assessing worsening PFTs, but larger studies are needed to confirm these preliminary data.Key Points• At baseline reticular pattern showed negative correlation with PFTs• At follow-up ground glass pattern predicts worsening of DLCO• CALIPER is a useful to quantify lung damage.

Portable Spirometer for Measuring Lung Function Health (FVC and FEV1)

Extreme climate change and air pollution caused by dust, smoke, vehicle exhaust gases and industry can increase the chances of contracting various infectious diseases caused by viruses, especially respiratory infections. Lung volume measurements obtained from air that is inhaled and exhaled by someone can help doctors diagnose abnormalities in the lungs. The purpose of this study was to develop an affordable pulmonary function measurement system, which is a spirometer. The main board consists of a non-inverting amplifier, Arduino microcontroller, LCD and SD Card memory. FVC and FEV1 volume measurements are carried out when the breath blew through the MPX5100DP gas pressure sensor. The sensor’s output is a voltage, which is converted to a volume unit using the venturimeter method. The SD card memory is used to store data. The results of measurement data on respondents with a spirometer comparison device then there is an FVC error of 0.98% 5, FEV1 3.83% and FEVI / FVC 2.50%. This value is still below the error tolerance limit of 5%. The design of this spirometer is portable and low cost to be made for mass production to help people to measure the health of lung function in humans.

Implications of spirometric reference values for amyotrophic lateral sclerosis

Objective: Spirometry is commonly used as screening tool for respiratory insufficiency in neuromuscular diseases. Despite the well-known effects of reference standards on spirometric outcomes, its standardization is overlooked in current guidelines. We aim to illustrate the effect of spirometric reference values on prognostication, medical decision-making, and trial eligibility in the applied setting of amyotrophic lateral sclerosis (ALS). Methods: We selected 4,651 patients with 32,022 FVC measurements from the PRO-ACT dataset. The FVC estimates were standardized according to five reference standards: Knudson ‘76, Knudson ‘83, ECSC, NHANES III, and GLI-2012. (Generalized) linear mixed-effects and Cox proportional hazard models were used to evaluate longitudinal patterns and time-to-event outcomes. Results: The mean population %predicted FVC varied between 78.5% (95% CI 78.0–79.1) and 88.5% (95% CI 87.9–89.1). The unstandardized liters provided the worst fit on the survival data (AIC 20573, c-index 0.760), whereas the GLI provided the best fit (AIC 20374, c-index 0.780, p < 0.001). The mean population rate of decline in %predicted FVC could vary as much as 11.4% between reference standards. The median time-to-50% predicted FVC differed by 2.9 months between recent (14.5 months, 95% CI 14.4–16.1) and early reference standards (17.4 months, 95% CI 16.1–18.2). Conclusion: Independent of technique, device, or evaluator, spirometric reference values affect the utility of spirometry in ALS. Standardization of reference values is of the utmost importance to optimize clinical decision-making, improve prognostication, enhance between–center comparison and unify patient selection for clinical trials.

Eligibility for anti-fibrotic treatment in idiopathic pulmonary fibrosis depends on the predictive equation used for pulmonary function testing.

Publicly funded therapy for idiopathic pulmonary fibrosis (IPF) relies on percentage predicted values from pulmonary function testing, for example Australian patients must have a forced vital capacity ≥50% (%FVC), transfer factor of the lung for carbon monoxide ≥ 30% (%TLco) and forced expiratory volume in 1 s (FEV1 )/FVC ratio > 0.7. Despite defined cut-off values, no jurisdiction prescribes a reference equation for use; multiple equations exist. We hypothesized that access to subsidized treatment varies depending on the chosen equation. The %FVC and %TLco from different commonly used reference equations across general respiratory patients, and IPF-specific patients, were compared. FVC and TLco measurements from a large general respiratory laboratory and the Australian Idiopathic Pulmonary Fibrosis Registry (AIPFR) database were analysed using multiple equations. Differences between %FVC and %TLco for each equation were calculated, with particular interest in classification of patients (%) at the threshold for subsidized treatment. A total of 20 378 general respiratory database results were analysed. The %FVC ≥ 50% increased from 86% with the Roca equation to 96% with Quanjer (European Coal and Steal Community, ECSC) and %TLco≥30% increased from 91% with Paoletti to 98% with Thompson. However, overall increase in eligibility for subsidized treatment was modest, varying from 48.2% to 49.2%. A total of 545 AIPFR database results were analysed. The %FVC ≥ 50% increased from 73% with Roca to 94% with Quanjer (ECSC) and %TLco≥30% increased from 87% with Paoletti to 96% with Miller. Overall eligibility for subsidized treatment in the AIPFR group varied from 73.6% to 82.8% between surveyed interstitial lung disease (ILD) centres based entirely on the equation used. Substantial variability exists between reference equations, impacting access to subsidized treatment. Treating clinicians should be aware of this when assessing patients around public funding thresholds.

Comparison of Forced and Slow Vital Capacity Maneuvers in Defining Airway Obstruction.

Obstructive lung disease is diagnosed by a decreased ratio of FEV1 to the vital capacity (VC). Although the most commonly used VC is FVC, American Thoracic Society guidelines suggest alternative VCs, for example, slow VC (SVC), may offer a more-accurate evaluation of breathing capacity. There is recent evidence that using only FEV1/FVC underrecognizes obstruction in subjects at high risk and who are symptomatic. Previous studies have indicated that healthy individuals show a minimum difference between FVC and SVC; however, testing of individuals with asthma and who are symptomatic indicates that SVC can be markedly larger than FVC. To evaluate the differences among SVC, FVC, and SVC-based measurements in the diagnosis of symptomatic obstructive lung disease. A retrospective analysis was performed of spirometry and plethysmography measurements from studies conducted between 2011 to 2015. We established a pulmonary function database that incorporated predictive equations from the National Health and Nutrition Examination Survey III (NHANES III). The SVC to FVC difference was calculated. FEV1/SVC was compared with FEV1/FVC by using NHANES III lower limit of normal values. A total of 2,710 studies with 2,244 subjects were reviewed. Spirometric obstruction, as defined by NHANES III, was identified in 26.1% of the studies (707/2,710). The mean (± SD) difference between SVC and FVC was 375.0 ± 623.0 mL and 258.8 ± 532.5 mL in those with and those without obstruction, respectively. Subgroup and multivariate analysis demonstrated age, body mass index, and FEV1 associated contributions to the difference between SVC and FVC. By using FEV1/SVC, the prevalence of obstruction increased from 26.1 to 45.0% (1,219/2,710) and identified 566 additional studies of subjects with obstruction. Fifty-four percent of the subjects with newly-identified obstructive lung disease (305/566) had smoking histories, and 67.4% (345/512) received medications for obstructive lung disease. The isolated use of FVC-based diagnostic algorithms did not recognize individuals with symptomatic obstructive lung disease. Recognizing the difference between SVC and FVC measurements in subjects will improve testing and diagnosis of obstructive lung disease.