American Thoracic Society Standards Research Articles

Assessing the prevalence and impact of preserved ratio impaired spirometry in low-income and middle-income countries: a post-hoc cross-sectional analysis

More than 90% of the morbidity and mortality from chronic respiratory disease occurs in low-income and middle-income countries (LMICs), with substantial economic impact. Preserved ratio impaired spirometry (PRISm) is a prevalent lung function abnormality associated with increased mortality in high-income countries. We aimed to conduct a post-hoc analysis of a cross-sectional study to assess the prevalence of, the risk factors for, and the impact of PRISm in three diverse LMIC settings. We recruited a random, age-stratified and sex-stratified sample of the population in semi-urban Bhaktapur, Nepal; urban Lima, Peru; and rural Nakaseke, Uganda. Quality-assured post-bronchodilator spirometry was performed to American Thoracic Society standards and PRISm was defined as a forced expiratory volume in one second (FEV1) of less than 80% predicted with a FEV1/forced vital capacity ratio of 0·70 or more. We used t tests and χ2 analyses to assess the relationships between demographic, biometric, and comorbidity variables with PRISm. Multivariable logistic models with random intercept by site were used to estimate odds ratios (ORs) with 95% CIs. 10 664 participants were included in the analysis, with a mean (SD) age of 56·3 (11·7) years and an equal distribution by sex. The prevalence of PRISm was 2·5% in Peru, 9·1% in Nepal, and 16·0% in Uganda. In multivariable analysis, younger age (OR for each decile of age 0·87, 95% CI 0·82-0·92) and being female (1·37, 1·18-1·58) were associated with increased odds of having PRISm. Biomass exposure was not consistently associated with PRISm across sites. Individuals with PRISm had impairment in respiratory-related quality of life as measured by the St George's Respiratory Questionnaire (OR by decile 1·18, 95% CI 1·10-1·25). The prevalence of PRISm is heterogeneous across LMIC settings and associated with age, female sex, and biomass exposure, a common exposure in LMICs. A diagnosis of PRISm was associated with worse health status when compared with those with normal lung function. Health systems in LMICs should focus on all spirometric abnormalities as opposed to obstruction alone, given the disease burden, reduced quality of life, and size of the undiagnosed population at risk. Medical Research Council.

Lung Clearance Index as a Screening Parameter of Pulmonary Impairment in Patients under Immune Checkpoint Therapy: A Pilot Study.

Background: Immune checkpoint blockade (ICB) has presented a breakthrough in the treatment of malignant tumors and increased the overall survival of patients with various tumor entities. ICB may also cause immune-related adverse events, such as pneumonitis or interstitial lung disease. The lung clearance index (LCI) is a multiple-breath washout technique offering information on lung pathology in addition to conventional spirometry. It measures the degree of pulmonary ventilation inhomogeneity and allows early detection of pulmonary damage, especially that to peripheral airways. Methods: This cross-sectional study compared the lung function of patients with melanoma or metastatic cutaneous squamous cell carcinoma who received programmed cell death 1 (PD-1) and cytotoxic T-Lymphocyte-associated Protein 4 (CTLA-4) antibodies, alone or in combination, to age- and sex-matched controls. Lung function was assessed using spirometry, according to American Thoracic Society and European Respiratory Society standards, the LCI, and a diffusion capacity of carbon monoxide (DLCO) measurement. Results: Sixty-one screened patients and thirty-eight screened controls led to nineteen successfully included pairs. The LCI in the ICB-treated patients was 8.41 ± 1.15 (mean ± SD), which was 0.32 higher compared to 8.07 ± 1.17 in the control group, but the difference was not significant (p = 0.452). The patients receiving their ICB therapy for under five months showed a significantly lower LCI (7.98 ± 0.77) compared to the ICB patients undergoing therapy for over five months (9.63 ± 1.22) at the point of testing (p = 0.014). Spirometric analysis revealed that the forced expiratory volume between 25 and 75% of the forced vital capacity (FEF25-75%) in the ICB-treated patients was significantly reduced (p = 0.047) compared to the control group. DLCO (%predicted and adjusted for hemoglobin) was 94.4 ± 19.7 in the ICB patients and 93.4 ± 21.7 in the control group (p = 0.734). Conclusions: The patients undergoing ICB therapy showed slightly impaired lung function compared to the controls. Longer periods of ICB treatment led to deterioration of the LCI, which may be a sign of a subclinical inflammatory process. The LCI is feasible and may be easily integrated into the clinical daily routine and could contribute to early detection of pulmonary (auto-)inflammation.

The Impact of Anterior Vertebral Body Tethering on Pulmonary Function.

Retrospective, single-center study. To examine pulmonary function tests (PFTs) in patients undergoing anterior vertebral body tethering (AVBT). The effect of AVBT on pulmonary status remains unclear. The authors examined preoperative and postoperative PFTs following AVBT in a retrospective, single-center cohort of patients. Outcomes were compared using percent predicted values as continuous and categorical variables (using 10% change as significant) and divided into categorical values based on the American Thoracic Society standards. Fifty-eight patients with adolescent idiopathic scoliosis were included, with a mean age of 12.5±1.4 years and a follow-up of 4.2±1.1 years. The mean thoracic curve was 47°±9°, which improved to 21°±12°. At baseline, the mean forced expiratory volume in one second (FEV1%) and forced vital capacity (FVC%) values were 79% and 82%, respectively. Four patients had normal FEV1% (≥100%), 67% had mild restrictive disease (70%-99%) and the rest had worse FEV1%. Mean FEV1 improved from 2.2 to 2.6 L ( P <0.05) and FVC improved from 2.5 to 3.0 L ( P <0.05); however, % predicted values remained unchanged (FEV1%: 79%-80%; FVC%: 82-80%, P >0.05) with mean postoperative PFTs at 37±12 months postoperative. The use of miniopen thoracotomy was not associated with worsening PFTs, but extension of the lowest instrumented vertebra below T12 was correlated with decreasing FEV1% in the bivariate analysis ( P <0.05). Patients with worse preoperative FVC% (80±13% vs. 90±11%, P =0.03) and FEV1% (77±17% vs. 87±12%, P =0.06) also had a greater likelihood of declining postoperative FEV1%. Pulmonary function in most patients undergoing AVBT remained stable (76%) or improved (14%); however, a subset may worsen (10%). Further studies are needed to identify the risk factors for this group, but worse preoperative PFTs and extension below T12 may be risk factors for worsening pulmonary function.

Do American Thoracic Society and European Respiratory Society Journals Have a Role in Promoting Official American Thoracic Society and European Respiratory Society Standards?

Do American Thoracic Society and European Respiratory Society Journals Have a Role in Promoting Official American Thoracic Society and European Respiratory Society Standards?

Deep learning algorithm for visual quality assessment of the spirograms

Objective. The quality of spirometry manoeuvres is crucial for correctly interpreting the values of spirometry parameters. A fundamental guideline for proper quality assessment is the American Thoracic Society and European Respiratory Society (ATS/ERS) Standards for spirometry, updated in 2019, which describe several start-of-test and end-of-test criteria which can be assessed automatically. However, the spirometry standards also require a visual evaluation of the spirometry curve to determine the spirograms’ acceptability or usability. In this study, we present an automatic algorithm based on a convolutional neural network (CNN) for quality assessment of the spirometry curves as an alternative to manual verification performed by specialists. Approach. The algorithm for automatic assessment of spirometry measurements was created using a set of randomly selected 1998 spirograms which met all quantitative criteria defined by ATS/ERS Standards. Each spirogram was annotated as ‘confirm’ (remaining acceptable or usable status) or ‘reject’ (change the status to unacceptable) by four pulmonologists, separately for FEV1 and FVC parameters. The database was split into a training (80%) and test set (20%) for developing the CNN classification algorithm. The algorithm was optimised using a cross-validation method. Main results. The accuracy, sensitivity and specificity obtained for the algorithm were 92.6%, 93.1% and 90.0% for FEV1 and 94.1%, 95.6% and 88.3% for FVC, respectively. Significance. The algorithm provides an opportunity to significantly improve the quality of spirometry tests, especially during unsupervised spirometry. It can also serve as an additional tool in clinical trials to quickly assess the quality of a large group of tests.

A Prospective Cohort Study (OUTSTRIP-COVID) on Functional and Spirometry Outcomes in COVID-19 ICU Survivors at 3 Months.

COVID-19 pandemic resulted in a significant number of critical care admissions secondary to severe pneumonia and acute respiratory distress syndrome. We evaluated the short-, medium- and long-term outcomes of lung function and quality of life in this prospective cohort study and reported the outcomes at 7 weeks and 3 months from discharge from intensive care unit. A prospective cohort study of ICU survivors with COVID-19 was conducted from August 2020 to May 2021 to evaluate baseline demographic and clinical variables as well as determine lung function, exercise capacity, and health-related quality of life (HRQOL) using spirometry and 6-minute walk test (6MWT) conducted in accordance with American Thoracic Society standards, and SF-36 (Rand), respectively. SF-36 is a generic 36 question standardized health survey. Descriptive and inferential statistics (alpha = 0.05) were used to analyse the data. At baseline, 100 participants were enrolled in the study of whom 76 followed up at 3 months. Majority of the patients were male (83%), Asians (84%) and less than 60 years of age (91%). HRQOL showed significant improvement in all domains of SF-36, except in emotional wellbeing. Spirometry variables also showed significant improvement in all variables over time with greatest improvement in percentage predicted Forced expiratory volume 1 (79% vs 88% p < 0.001). 6MWT showed significant improvement in variables of walk distance, dyspnea, and fatigue with greatest improvement in change in oxygen saturation (3% vs 1.44% p < 0.001). Intubation status did not impact the changes in SF-36, spirometry or 6MWT variables. Our findings suggest that ICU survivors of COVID-19 have significant improvement in their lung function, exercise capacity and HRQOL within 3 months of ICU discharge regardless of intubation status.

The effect of diuretics on spirometric parameters in patients with ischemic heart failure

Heart failure is the failure of the cardiac pump under physiological loading conditions to impart sufficient hydraulic energy output in order to maintain a physiological circulation. A cohort study extended over a period of 14 months from the first of august 2010 to the first of November 2011. The patient was diagnosed as having heart failure according to the recommendation of the European Society of Cardiology, depending on the result of history, examination and echocardiographic conformation. Spirometric data were collected in accordance with American Thoracic Society standards. All the patients had a restrictive spirometric defect before treatment with diuretics, but after treatment all show normal spirometric pattern. The present study recommend the followings: - The use of a cheap office spirometer in rural area by general practitioner (GP) doctors and nursing staff could be useful for follow up patients with ischemic heart failure to detect early deterioration by objective mean to refer the patient for specialized care. Also, the office spirometer needs no special skills and the nursing staff can master the procedure with a 2 weeks training course.

Race and Ethnicity in Pulmonary Function Test Interpretation: An Official American Thoracic Society Statement.

Current American Thoracic Society (ATS) standards promote the use of race and ethnicity-specific reference equations for pulmonary function test (PFT) interpretation. There is rising concern that the use of race and ethnicity in PFT interpretation contributes to a false view of fixed differences between races and may mask the effects of differential exposures. This use of race and ethnicity may contribute to health disparities by norming differences in pulmonary function. In the United States and globally, race serves as a social construct that is based on appearance and reflects social values, structures, and practices. Classification of people into racial and ethnic groups differs geographically and temporally. These considerations challenge the notion that racial and ethnic categories have biological meaning and question the use of race in PFT interpretation. The ATS convened a diverse group of clinicians and investigators for a workshop in 2021 to evaluate the use of race and ethnicity in PFT interpretation. Review of evidence published since then that challenges current practice and continued discussion concluded with a recommendation to replace race and ethnicity-specific equations with race-neutral average reference equations, which must be accompanied with a broader re-evaluation of how PFTs are used to make clinical, employment, and insurance decisions. There was also a call to engage key stakeholders not represented in this workshop and a statement of caution regarding the uncertain effects and potential harms of this change. Other recommendations include continued research and education to understand the impact of the change, to improve the evidence for the use of PFTs in general, and to identify modifiable risk factors for reduced pulmonary function.

Diagnostic Performance of Forced Expiratory Volume in Six Seconds for the Detection of Obstructive and Restrictive Pulmonary Diseases in a Population of Young Adults in South of Iran

Background: Forced expiratory volume in 6 seconds (FEV6) is a reliable substitute for forced vital capacity (FVC) to identify pulmonary diseases. This study aimed to determine the diagnostic performance of FEV6 in the detection of obstructive and restrictive spirometric patterns. Methods: In this cross-sectional study, spirometry was performed on patients referred to the occupational medicine clinic of Shahid Mohammadi Hospital, Bandar Abbas, Iran, 2018. Spirometric parameters, including FEV1, FVC, and FEV6, were recorded for those tests meeting the American Thoracic Society (ATS) standards. Taken as the reference, the FEV1/FVC ratio&lt;70% indicated airway obstruction, and the restrictive pattern was defined as FVC&lt;80%. Results: In general, 1100 spirometries were included after meeting the ATS standards. The optimal cut-off of FEV1/FEV6 for the prediction of airway obstruction was 71.45% with a sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of 97.22%, 98.22%, 89.17%, 99.57%, and 98.09%, respectively. The best cut-off of FEV6 for the prediction of the restrictive pattern was 79.23% with the corresponding diagnostic indices of 97.29%, 99.05%, 94.11%, 99.57%, and 98.81%, respectively. Based on the FEV1/FEV6 cut-off, the frequency of obstruction was 14.27% (157/1100) compared to 13.09% based on FEV1/FVC. The frequency of restriction was 13.90% (153/1100) according to the FEV6 cut-off compared to 13.45% with respect to FVC. Conclusion: Overall, our results indicated the applicability of FEV1/FEV6 as an accepted surrogate for FEV1/FVC to diagnose airway obstruction, particularly to screen for chronic obstructive pulmonary disease (COPD) among high-risk patients. In addition, FEV6 is potentially an appropriate substitute for FVC to detect a restrictive pattern.

Chronic respiratory symptoms and lung function parameters in large-scale wood factory workers in Addis Ababa, Ethiopia: a comparative cross-sectional study.

Occupational wood dust causes chronic respiratory health problems as well as a decline in lung function. However, data on the prevalence of chronic respiratory symptoms and lung function parameters among large-scale wood factories workers in Ethiopia producing furniture are limited. The objective of this study was to determine the prevalence of chronic respiratory symptoms, lung function measures, and associated factors among large-scale wood industry workers in Addis Ababa, Ethiopia. An institution-based cross-sectional study was conducted among 232 wood workers and 232 controls. Participants for the study were selected using stratified and systematic sampling from soft drink and wood factories. The chronic respiratory symptoms were assessed using a modified American Thoracic Society (ATS) questionnaire, and lung function tests were performed using an Easy on PC spirometer in accordance with the ATS standards for spirometry. The data were imported into Epi-data version 4.4.2 and analyzed with SPSS version 23. Poisson regression, Multivariate linear regression and multivariable logistic regression analysis were used. The prevalence ratio of overall chronic respiratory symptoms was significantly higher among woodworkers (65.7%) compared to controls (23.3%) in this study (PR = 2.17, 95% CI: 1.51-3.12). Current chronic respiratory symptoms were associated with gender, and previous chronic respiratory disease. Woodworkers had significantly lower Forced vital capacity (FVC) and Forced expiratory volume in the first second (FEV1) when compared to controls. Woodworkers had a higher prevalence of chronic respiratory symptoms and lower lung function measures, which lowered lung capacity when compared to controls. To reduce workers' exposure to wood dust, engineering control methods should be implemented.

P57. A double blind, randomized controlled, prospective trial assessing the effectiveness of oral corticoids in the treatment of symptomatic lumbar stenosis

P57. A double blind, randomized controlled, prospective trial assessing the effectiveness of oral corticoids in the treatment of symptomatic lumbar stenosis

Pulmonary Hypertension Clinical Trials and COVID-19: A Discussion With John Ryan and Roham Zamanian

Pulmonary Hypertension Clinical Trials and COVID-19: A Discussion With John Ryan and Roham Zamanian

A Dose–Response Study to Examine the Methodology for Demonstrating the Local Therapeutic Equivalence of the Fluticasone Propionate Component of an Orally Inhaled Combination Therapy of Fluticasone Propionate/Salmeterol Dry Powder

Background: Asthma is widely treated using inhaled corticosteroid/long-acting beta-agonist combinations, such as fluticasone propionate/salmeterol (FPS) dry powder inhaler. Some regulators require generic medications to demonstrate local therapeutic equivalence (LTE) for each component of the FPS reference product. Fractional exhaled nitric oxide (FeNO) was developed as a possible LTE endpoint for the fluticasone propionate (FP) component of FPS in a randomized, double-blind, crossover study in steroid-naive asthma patients with elevated FeNO (≥45 parts per billion). Methods: Thirty-four patients received three of five treatments: FPS 100/50 μg once daily (QD), FPS 100/50 μg twice daily (BID), FPS 250/50 μg BID, FPS 500/50 μg BID, or placebo, each for 2 weeks separated by 14-day washout. FeNO was measured on days 1, 2, 3, 5, 7, and 14 of each period, according to American Thoracic Society standards. Results: FPS treatments decreased FeNO compared with placebo, with the largest differentiation between doses noted on day 14; the mean decreases from days 1 to 14 ranged from -46.6% to -64.5% with FPS versus -9.1% with placebo. The dose-response plateaued at 200 μg/day (FPS 100/50 μg BID). Linear regression analysis revealed significant slopes between FPS doses, with the steepest between 100/50 μg QD and 100/50 μg BID (-0.0039, p = 0.020). An estimated sample size (SS) of 160 or 48 patients would be required to demonstrate LTE of generic and FPS reference products (0.80-1.25 and 0.67-1.50 bioequivalence limits, respectively). However, as the slope between BID FPS doses was shallow, a larger SS may be needed if only an approved dose regimen was used. Conclusion: FeNO could be a valid endpoint to determine LTE between the FP component of generic and reference FPS products, but only if QD dosing and wide equivalence limits are included. As QD dosing is not an approved regimen, this approach is unlikely to be acceptable.

Lung function and respiratory symptoms among mine workers in the Eastern part of Iran

Background ― Workers in the mineral industries are exposed to airborne dust and its occupational exposure can cause respiratory disorders. The aim of this study was to determine the lung function and respiratory symptoms of workers exposed to mineral dust in the Eastern part of Iran. Material and Methods ― This cross-sectional study was conducted on 156 workers in kaolin mine, gold mine, quarry, and stone cutting workshops as a dust exposed group and 48 administrative personnel in these sections as an unexposed group. After the general medical examination and completion of the demographic questionnaire, workers’ pulmonary function test was performed for each person using a spirometer according to the American Thoracic Society standards. Finally, data analysis was performed using Tukey's post hoc and chi-squared tests. Results ― The mean age in the exposed group to dust and control group were 33.8±7.9 and 36.7±8.0 years (data are presented as mean with standard deviation), weight – 75.1±13.0 and 75.0±11.2 kg, height – 173.2±6.8 and 173.1±6.3 cm, and work experience – 9.1±4.6 and 8.4±5.3 years, respectively. There was no significant difference between the working groups in the kaolin, gold, quarry, and stone cutting sections and the control group on the demographic variables. The mean value of the lung function parameters was lower in different working groups than in the control group. Significant differences were observed between the two groups in forced vital capacity and forced expiratory volume in 1 second parameters (P<0.05); however, there was no significant difference between them in peak expiratory flow and forced expiratory flow 25-75% (P>0.05). Conclusion ― The results showed the exposed groups have significantly lower pulmonary function than the control group. Two out of four main pulmonary function variables showed reduce amounts in exposed groups.

Impulse oscillometry and obesity in children

ObjectiveTo compare impulse oscillometry system parameters of normal‐weight children with overweight and obese children. MethodAll participants were submited to the evaluation of lung function (spirometry and impulse oscillometry) following the American Thoracic Society standards. The evaluation of respiratory mechanics was performed using the JaegerTM MasterScreenTM Impulse Oscillometry System (Erich Jaeger, Germany), three tests were recorded, with acquisition for at least 20 seconds. ResultsThe study included 81 children (30 in the control group, 21 in the overweight group, and 30 the in obesity group), matched for age and sex. Regarding spirometry data, obesity group showed higher numerical values in relation to the control group; however, there were no significant differences among the three groups. For impulse oscillometry parameters, there was a difference between control group and obesity group for respiratory impedance (p=0.036), resistance at 5hertz (p=0.026), resonant frequency (p=0.029), and reactance area (p=0.014). For the parameters expressed in percentage of predicted, there were differences in resistance at 5 hertz, resonant frequency and reactance area between control group and obesity group. ConclusionsObese children showed increased oscillometry parameters values representative of airway obstruction, compared to normal‐weight children. Changes in some oscillometry parameters can already be observed in overweight school‐aged children.

Impulse oscillometry and obesity in children

ObjectiveTo compare impulse oscillometry system parameters of normal-weight children with overweight and obese children. MethodAll participants were submitted to the evaluation of lung function (spirometry and impulse oscillometry) following the American Thoracic Society standards. The evaluation of respiratory mechanics was performed using the Jaeger™ MasterScreen™ Impulse Oscillometry System (Erich Jaeger, Germany), three tests were recorded, with acquisition for at least 20seconds. ResultsThe study included 81 children (30 in the control group, 21 in the overweight group, and 30 the in obesity group), matched for age and sex. Regarding spirometry data, obesity group showed higher numerical values in relation to the control group; however, there were no significant differences among the three groups. For impulse oscillometry parameters, there was a difference between control group and obesity group for respiratory impedance (p=0.036), resistance at 5hertz (p=0.026), resonant frequency (p=0.029), and reactance area (p=0.014). For the parameters expressed in percentage of predicted, there were differences in resistance at 5 hertz, resonant frequency, and reactance area between control group and obesity group. ConclusionsObese children showed increased oscillometry parameters values representative of airway obstruction, compared to normal-weight children. Changes in some oscillometry parameters can already be observed in overweight school-aged children.

Effects of Cigarettes Smoking on Pulmonary Function among University Students

Pulmonary function testing is a physiological test that measures how an individual inhales or exhales volumes of air as a function of time. Smoking is greatly associated with reduction of pulmonary function. This research is aimed to estimate the values of peak expiratory flow (PEF), forced expiratory volume in first second (FEV1), forced vital capacity (FVC) and ratio between FEV1/FVC among smoking and non-smoking students in Universiti Tun Hussein Onn Malaysia. Smoking is often related to obstructive disorder with low value of FVC, FEV1 and FEV1/FVC. These pulmonary functions were analyzed based on several variables such as; the number of cigarette smoked per day, duration of smoking, age, and body mass index (BMI) values. 70 healthy volunteers consist of smoking and non- smoking students was selected through several sessions. Students were interviewed to answer questionnaire on demographic, lifestyles and their smoking habit. The pulmonary function tests were conducted according to American Thoracic Society (ATS) standards. The results of the pulmonary functions were analyzed by using SPSS software to compare the pulmonary functions between the smoker and the non-smoker students. The results of the studies showed that the number of cigarettes smoked by respondent and the BMI values were the significant predictors of the decrease in FEV1/FVC values among university students

Estimation of height in males from anthropometric measurements of upper limbs

Variations in pulmonary function tests (PFTs) due to agriculture crop residue burning (ACRB) on children between the age group of 10 to 13 years and the young between 20 to 35 years are studied. The effects of exposure to smoke due to rice–wheat crop residue burning on pulmonary functions like Force Vital Capacity (FVC), Force Expiratory Volume in one second (FEV1), Peak Expiratory Flow (PEF) and Force Expiratory Flow in 25 to 75% of FVC (FEF25–75%) on 40 healthy subjects of rural/agricultural area of Sidhuwal village of Patiala City were investigated for a period from August 2008 to July 2009. Measurements were taken by spirometry according to the American Thoracic Society standards. High volume sampler (HVS) and Anderson Impactor were used to measure the concentration levels of SPM, PM10 and PM2.5 in ambient air of the Sidhuwal village. A significant increase in the concentration levels of SPM, PM10 and PM2.5 was observed due to which PFTs of the subjects showed a significant decrease in their values, more prominently in the case of children. PFTs of young subjects recovered up to some extent after the completion of burning period but the PFT values of children remained significantly lower (p < 0.001) even after the completion of burning episodes. Small size particulate matter (PM2.5 and PM10) affected the PFTs to a large extent in comparison to the large size particulate matter (SPM). The study indicates that ACRB is a serious environmental health hazard and children are more sensitive to air pollution, as ACRB poses some unrecoverable influence on their PFTs.

A role of pulmonary function testing for detecting ventilation and gas exchange disorders in multilobar community-acquired pneumonia convalescents

The aim of this study was to analyze lung function in multilobar community-acquired pneumonia (CAP) convalescents. Methods. Spirometry, body plethysmography, and lung diffusing capacity were measured according to the joint European Respiratory Society and American Thoracic Society standards (2005). The carbon monoxide lung diffusing capacity was evaluated using a single breath-hold technique and was adjusted for hemoglobin. Results . The complete clinical and radiological resolution of CAP did not accompanied by recovery of lung function in all cases. Obstructive ventilation disorders were diagnosed in 18.2% of patients, restrictive ventilation disorders were diagnosed in 12.1% of patients, and gas exchange abnormalities were diagnosed in 51.5% of the patients. Conclusion. Lung function and gas exchange testing is an important marker of the patient's convalescence after CAP and duration of the recovery; it also could predict the need in subsequent follow-up.

Reference Equations for Impulse Oscillometry System Parameters in Healthy Brazilian Children and Adolescents

The impulse oscillometry system is a noninvasive method of evaluating respiratory mechanics that is being increasingly used in the pediatric population. To date, no reference equations have been developed for healthy Brazilian children and adolescents. The purpose of the study was to determine the reference equations for impulse oscillometry system parameters in healthy children and adolescents. We undertook an observational cross-sectional analytical study with healthy students age 6-14 y from educational institutions in the Greater Florianópolis area. Biometric data were evaluated (weight, height, body mass index, and body surface area) as predictors and for sample characterization. All participants were submitted to evaluation of respiratory mechanics using an oscillometry system following American Thoracic Society standards. Three tests were recorded, with data acquisition for ≥20 s. For data normality verification, the Kolmogorov-Smirnov test was applied, and Pearson's correlation test identified the relationship between the predicted values of height, age, and weight and the oscillometric variables of resistance at 5 and 20 Hz reactance; respiratory impedance at 5 Hz resonant frequency; and reactance area. Models were developed using simple linear regression and multiple analyses. After the recruitment of 864 children, 123 subjects with an average age of 10.0 ± 2.4 y for boys and 9.9 ± 2.4 y for girls (P = .94) were considered for final analysis. Correlations were identified between the dependent and predictor oscillometric variables, with height identified as having the greatest predictive power in the equations developed for boys in all oscillometric parameters, with a mean adjusted R(2) of 46.51%. Age had greater influence on resonant frequency (adjusted R(2) = 40.1%) and reactance area (adjusted R(2) = 48.8%) for girls. Reference equations were developed for males and females, and height was the most influential predictor variable for most impulse oscillometry system parameters in the population studied.