Objective: To use the forced oscillation technique to evaluate asthma patients presenting positive bronchodilator responses (confirmed through spirometry) and compare the results with those obtained in healthy individuals. Methods: The study sample consisted of 53 non-smoking volunteers: 24 healthy subjects with no history of pulmonary disease and 29 asthmatics presenting positive bronchodilator response, as determined through analysis of spirometry findings. All of the subjects were submitted to forced oscillation technique and spirometry immediately before and 20 minutes after the administration of salbutamol spray (300 g). The parameters derived from the forced oscillation technique were total respiratory resistance, total respiratory reactance, resistance extrapolated to the y axis, the slope of resistance, and dynamic compliance. The parameters measured in the spirometry evaluation tests were forced expiratory volume in one second and forced vital capacity. Results: In the control group, bronchodilator use produced a significant alteration in the resistance extrapolated to the y axis (p < 0.001), although no significant differences were observed in the slope of resistance or in dynamic compliance. Analysis of the asthma patients revealed significant differences between the prebronchodilator and postbronchodilator values for all spirometry and forced oscillation technique parameters. Values of p < 0.001 were obtained for all comparisons between the two groups. Conclusion: The modifications provoked by use of the forced oscillation technique were in direct concordance with the pathophysiology of the bronchodilator response in asthma patients, indicating that the forced oscillation technique could be useful as a complement to spirometry in these patients.

Keywords: Asthma; Bronchial hyperreactivity; Spirometry/methods; Bronchial provocation tests; Forced expiratory volume/physiology; Oscillometry

Objective: To evaluate the resistance values obtained through the use of the forced oscillation technique in patients with varying degrees of airway obstruction resulting from silicosis. Methods: A total of 40 never-smoking volunteers were analyzed: 10 were healthy subjects with no history of pulmonary disease or silica exposure, and 30 had silicosis. The forced oscillation technique was used to examine the subjects, and spirometry was used as a reference in order to classify the obstruction by degree. This classification resulted in five groups: control (n = 10); normal exam, composed of individuals diagnosed clinically and radiologically with silicosis but presenting normal spirometry results (n = 7); mild obstruction (n = 10); moderate obstruction (n = 8); and severe obstruction (n = 5). Results: The reduction observed in the spirometric values corresponded to a significant increase in the total respiratory resistance (p < 0.001), as well as in airway resistance (p < 0.003). A significant reduction in ventilation homogeneity was also observed (p < 0.004). Conclusion: In individuals with silicosis, the additional respiratory resistance-related data obtained through the use of the forced oscillation technique can complement spirometric data. Therefore, the forced oscillation technique presents great potential for the analysis of such patients.

Keywords: Pneumoconiosis; Silicosis; Forced expiratory volume; Oscillometry; Respiratory function tests

Objective: To investigate the effects of airway obstruction on albuterol-mediated variations in the resistive and elastic properties of the respiratory system of adult patients with asthma. Methods: This study comprised 24 healthy controls and 69 patients with asthma, all of whom were nonsmokers. The patients were divided into three groups according to the severity of airway obstruction (mild, moderate or severe). Each of the three groups was divided into two subgroups according to the bronchodilator response (BR): positive (BR+) or negative (BR−). These measurements were conducted before and after albuterol use (300 µg). Airway obstruction was determined by means of spirometry, and the resistive and elastic properties were determined by means of the forced oscillation technique. Results: The resistance at the intercept (R0) presented greater reductions in the groups with higher obstruction. This reduction was more evident in the BR+ subgroups than in the BR− subgroups (p < 0.02 and p < 0.03, respectively). There was a significant difference between the control group and the BR+ subgroup with severe obstruction (p < 0.002). The reductions in dynamic elastance (Edyn) were significantly greater in proportion to the degree of obstruction, in the BR− subgroups (p < 0.03), and in the BR+ subgroups (p < 0.003). The reductions in Edyn were significantly greater in the BR− subgroup with moderate obstruction (p < 0.008) and in the BR+ subgroup with severe obstruction (p < 0.0005) than in the control group. Conclusions: In patients with asthma, increased airway obstruction results in greater reductions in R0 and Edyn after albuterol use. These reductions are greater among BR+ patients than among BR− patients.

Keywords: Asthma; Bronchodilator agents; Respiratory mechanics; Spirometry; Albuterol.

Objetivo: Medir a resistência de vias aéreas utilizando a técnica de resistência do interruptor (Rint) em pacientes com fibrose cística (FC) e correlacioná-la com parâmetros espirométricos, assim como avaliar a acurácia de Rint para determinar a resposta das vias aéreas a um broncodilatador. Métodos: Estudo transversal com 38 crianças e adolescentes com FC acompanhados no Ambulatório de FC do Hospital São Lucas, em Porto Alegre (RS). Após a determinação de Rint, os pacientes foram submetidos à espirometria. Para a avaliação da resposta ao broncodilatador, as medições foram repetidas após o uso de salbutamol inalatório. Resultados: Houve uma forte correlação entre o inverso de Rint e VEF1 (r = 0,8; p < 0,001) e moderadas correlações entre o inverso de Rint e FEF25-75% (r = 0,74; p < 0,001) e entre o inverso de Rint e índice de massa corpórea (r = 0,62; p < 0,001). A curva ROC foi utilizada na comparação da resposta ao broncodilatador determinada por Rint com aquela determinada por valores espirométricos. Para um ponto de corte de −28% para Rint, a área sob a curva foi de 0,75, com uma sensibilidade de 66% e uma especificidade de 82%. Conclusões: Nossos achados indicam que Rint apresenta uma boa correlação com parâmetros espirométricos, embora a técnica Rint não tenha sido suficientemente acurada para substituir a espirometria na avaliação da resposta ao broncodilatador.

Keywords: Testes de função respiratória; Fibrose cística; Espirometria; Resistência das vias respiratórias.

Objective: To compare two methods of respiratory inductive plethysmography (RIP) calibration in three different positions. Methods: We evaluated 28 healthy subjects (18 women and 10 men), with a mean age of 25.4 ± 3.9 years. For all of the subjects, isovolume maneuver calibration (ISOCAL) and qualitative diagnostic calibration (QDC) were used in the orthostatic, sitting, and supine positions. In order to evaluate the concordance between the two calibration methods, we used ANOVA and Bland-Altman plots. Results: The values of the constant of proportionality (K) were significantly different between ISOCAL and QDC in the three positions evaluated: 1.6 ± 0.5 vs. 2.0 ± 1.2, in the supine position, 2.5 ± 0.8 vs. 0.6 ± 0.3 in the sitting position, and 2.0 ± 0.8 vs. 0.6 ± 0.3 in the orthostatic position (p < 0.05 for all). Conclusions: Our results suggest that QDC is an inaccurate method for the calibration of RIP. The K values obtained with ISOCAL reveal that RIP should be calibrated for each position evaluated.

Keywords: Plethysmography; Respiratory mechanics; Posture; Calibration.

Abstract Objective: To evaluate whether respiratory therapy techniques influence the number of cells within and quantity of induced sputum in patients with asthma or chronic obstructive pulmonary disease (COPD). Methods: Randomized clinical trial, in which patients with asthma or COPD under intervention (n = 16 and 10, respectively) were compared with control groups (n = 16 and 10). Patients in the asthma/intervention (A/I) and COPD/intervention (C/I) groups were submitted to oscillating positive expiratory pressure maneuvers for 5 min, followed by 10 forced expiratory technique sequences. These patients were also submitted to an induced sputum protocol with inhaled hypertonic saline (3%, 4% or 5%; A/I group) or inhaled isotonic saline (C/I group). The asthma/control (A/C) and COPD/control (C/C) groups were submitted only to the standard induced sputum protocol. Results: The final mean weight of the sputum samples was significantly greater in the A/I group than in the A/C group (2,767.25 ± 998.08 mg vs. 1,689.17 ± 1,189.96 mg; p = 0.03). The mean/median total cell counts (×106/mL) were higher in the A/I and C/I groups than in the A/C and C/C groups (4.06/0.95 and 0.63/0.39, p = 0.05, vs. 5.08/1.77 and 0.64/0.40, p = 0.02). There were no statistically significant differences among the groups in terms of cell viability. Conclusions: The use of respiratory therapy techniques can increase sputum sample weight in asthma patients, as well as increasing total cell counts in patients with asthma or COPD.

Keywords: Asthma; Pulmonary disease, obstructive chronic; Sputum; Physical therapy modalities.

Objective: Physiologically, VC can vary according to gender, age, body weight and posture, as well as ethnic and anthropometric characteristics. In addition, various diseases can alter VC. In order to measure VC, it is necessary to motivate the patient, to make the instructions understandable, to provide clear information and to have a capable examiner. The objective of this study was to determine the impact that positive reinforcement during spirometry has on the measurement of VC in healthy volunteers. Methods: A randomized clinical trial involving 105 healthy volunteers, randomly allocated to one of two groups: control and intervention. In both groups, VC was assessed as baseline (VC1) and again 15 days later (VC2). Positive reinforcement was provided only to patients in the intervention group and only during the determination of VC2. Results: There were no significant differences between the groups regarding the baseline characteristics. Females predominated in both groups. There was an increase in VC2 in both groups (p < 0.01), and VC2 was higher in the intervention group than in the control group (p < 0.01). Conclusions: These findings demonstrate the importance of using the behavioral strategy in combination with traditional practice in order to obtain better results. The use of positive reinforcement during the determination of VC has proven to be an effective, simple and easily applied strategy.

Keywords: Vital capacity; Reinforcement, verbal; Respiratory function tests.

Objective: To evaluate, using pulmonary function tests, the effectiveness of formoterol as a bronchodilator at 30 min after its administration in patients with poorly reversible COPD. Methods: A prospective study including 40 COPD patients not responding to the short-acting bronchodilator used in the spirometric test-variation of less than 200 mL and less than 7% of predicted in forced expiratory volume in one second (FEV1). All patients were classified as having stage II, III, or IV COPD (Brazilian Thoracic Society/Global Initiative for Chronic Obstructive Lung Disease) and presented FEV1 ≤ 70% of predicted value. The patients were randomized into two groups of 20, with similar clinical characteristics, receiving, via a dry powder inhaler, either formoterol or a placebo. The pulmonary function testing (plethysmography) was repeated at 30 min after formoterol or placebo administration. Results: In the formoterol group, the mean values obtained for FEV1, inspiratory capacity, and forced vital capacity were significantly greater than those obtained in the placebo group (p = 0.00065, p = 0.05, and p = 0.017, respectively), whereas that obtained for airway resistance was significantly lower (p = 0.010). Less pronounced differences were observed for residual volume, vital capacity and specific airway conductance, which were lower, higher and higher, respectively, in the formoterol group. Conclusions: In COPD patients not responding to the short-acting bronchodilator used in the spirometric test, formoterol promoted significant improvement in lung function at 30 min after of administration. Further studies are required to confirm whether formoterol can also be used as a medication for immediate relief of symptoms in COPD.

Keywords: Chronic obstructive pulmonary disease; Respiratory function tests; Bronchodilator agents.

Objective: Current debates on the bronchodilator response in COPD patients and whether the variation in FEV1 can be considered as an indicator of complete reversibility in such patients motivated us to conduct this study. The objective of the study was to determine the effect of albuterol on the resistive and reactive properties of the respiratory system in COPD patients. Methods: We evaluated 70 patients with COPD, divided into two groups based on spirometry findings: bronchodilator (BD)-negative (n = 39); and BD-positive (n = 31). We used the forced oscillation technique (FOT) to evaluate the following parameters: resistance at the intercept (R0), associated with the total resistance of the respiratory system; mean resistance (Rm), associated with central airway resistance; dynamic compliance (Cdyn); and the slope of resistance (S) and mean reactance (Xm), both of which are associated with the homogeneity of the respiratory system. Results: The use of albuterol resulted in significant reductions in R0 (p < 0.00002) and Rm (p < 0.0002). There were also significant increases in S (p < 0.0001), Cdyn (p < 0.0001) and Xm (p < 0.00004). These modifications occurred in both groups, the changes in FOT parameters being greater than those observed for spirometric parameters. Conclusions: The use of albuterol improved the resistive and reactive properties of the respiratory system of the COPD patients under study. These changes occurred regardless of the FEV1-based classification, thereby indicating that the use of this parameter in isolation might not suffice to identify the physiological effects involved.

Keywords: Pulmonary disease, chronic obstructive; Bronchodilator agents; Spirometry; Albuterol.

Objective: Making the differential diagnosis between asthma and chronic obstructive pulmonary disease (COPD) based on the response to inhaled bronchodilators by means of spirometry is controversial.The objective of this study was to identify the most useful spirometric variables in order to distinguish between asthma and COPD. Methods: Retrospective study conducted from April of 2004 to January of 2006, comparing the spirometric parameters of 103 nonsmoking patients with asthma to those of 108 patients with COPD who were smokers for more than 10 pack-years. All of the patients included in the study were older than 40 and presented stable disease at the time of the test. Results: Initial forced expiratory volume in one second (FEV1) was the same in the two groups (pre-bronchodilator FEV1 = 51%). However, patients with COPD were older (66 ± 9 years vs. 59 ± 11 years, p < 0.001) and more frequently male (73% vs. 27%, p < 0,001).After the use of the bronchodilator, the median absolute difference in FEV1 was 0.25 L (range, −0.09 to 1.13 L) in patients with asthma and 0.09 L (range, −0.1 to 0.73 L) in those with COPD (p < 0.001).The highest sensitivity (55%), specificity (91%) and likelihood ratio (6.1) for asthma diagnosis was obtained when the percentage increase in postbronchodilator FEV1 in relation to the predicted FEV1 (Δ%predFEV1) was equal to or greater than 10%.Isolated significant increases in forced vital capacity were more common in patients with COPD. Conclusions: In patients over the age of 40 and presenting obstructive lung disease, a Δ%predFEV1 ≥ 10% is the best spirometric parameter to distinguish asthma from COPD.

Keywords: Spirometry; Respiratory function tests; Lung diseases, obstructive.

Objective: To determine the cut-off points for FEV1, FEV0.75, FEV0.5, and FEF25-75% bronchodilator responses in healthy preschool children and to generate reference values for FEV0.75. Methods: This was a cross-sectional community-based study involving children 3-5 years of age. Healthy preschool children were selected by a standardized questionnaire. Spirometry was performed before and after bronchodilator use. The cut-off point of the response was defined as the 95th percentile of the change in each parameter. Results: We recruited 266 children, 160 (60%) of whom were able to perform acceptable, reproducible expiratory maneuvers before and after bronchodilator use. The mean age and height were 57.78 ± 7.86 months and 106.56 ± 6.43 cm, respectively. The success rate for FEV0.5 was 35%, 68%, and 70% in the 3-, 4-, and 5-year-olds, respectively. The 95th percentile of the change in the percentage of the predicted value in response to bronchodilator use was 11.6%, 16.0%, 8.5%, and 35.5% for FEV1, FEV0.75, FEV0.5, and FEF25-75%, respectively. Conclusions: Our results provide cut-off points for bronchodilator responsiveness for FEV1, FEV0.75, FEV0.5, and FEF25-75% in healthy preschool children. In addition, we proposed gender-specific reference equations for FEV0.75. Our findings could improve the physiological assessment of respiratory function in preschool children.

Keywords: Spirometry; Bronchodilator agents; Reference values; Child, preschool.

The aim of this study was to analyze the results of 17 patients with myasthenia gravis who, from 1985 to 1994, were submitted to thymectomy at the Medical School of Santa Casa de São Paulo. Nine patients (52.9%) were female and the mean age was approximately 30.3 years. The most usual symptoms were ptoses, weakness, and diplopia. Other symptoms included: dyspnea, dysphonia, thoracic pain and loss of weight. The average development period of the disease was 17.5 months (between 3 and 96 months). The diagnostic methods use were chest X-ray, response to edrophonium chloride (Tensilon), electrophysiologic study and thoracic CT. All patients were submitted to thymectomy through medium sternotomy. Patients were followed up from one month to ten years. Only one patient did not return to the clinic. Twelve patients (75%) achieved good results. The others four patients presented little or no response after thymectomy.

Keywords: Thymectomy. Myasthenia gravis.

Objective: To determine the occurrence of exercise-induced bronchoconstriction and analyze cardiorespiratory response during maximal exercise in asthmatic patients. Patients and methods: Fourteen subjects with asthma (FEV1 of 86.3% predicted), as defined by the American Thoracic Society criteria were submitted to a maximal exercise test. Volume-flow curves were performed prior to progressive maximal exercise and seven and 15 minutes after it. Six patients (43%) showed a decline in FEV1 equal or greater than 15% after exercise (group I). The remaining patients constituted group II. Group I showed a FEV1 fall of 40.9% and 26.7%, seven and 15 minutes after exercise, respectively. In group II, there was a decrease of 2.6%, after 7 min and an increase of 1.2% after 15 min. At peak exercise, both groups reached heart rate above 91% of reference values; peak work was 82.7% and 62.5%, VO2max (mL/kg/min) 93.5% and 58,9% and VEmax 91.5% and 63.8%, respectively, in groups I and II. These differences were statistically significant. The correlation between the FEV1 fall rate (7 min post-exercise) and VEmax (% predicted) has showed a coefficient r = 0.8989 in group I and r = 0.3629 in group II. There was no correlation between delta VEF1 and VO2max (% predicted) in both groups. These findings showed that, in exercise-induced asthma patients, the occurrence of bronchoconstriction correlated with the level of maximal ventilation, but not with physical fitness.

Keywords: Exercise induced asthma. Bronchoconstriction. Tidal volume. Respiratory function tests.

Objective: Post-infectious bronchiolitis obliterans (PIBO) is a clinical entity that has been classified as constrictive, fixed obstruction of the lumen by fibrotic tissue. However, recent studies using impulse oscillometry have reported bronchodilator responses in PIBO patients. The objective of this study was to evaluate bronchodilator responses in pediatric PIBO patients, comparing different criteria to define the response. Methods: We evaluated pediatric patients diagnosed with PIBO and treated at one of two pediatric pulmonology outpatient clinics in the city of Porto Alegre, Brazil. Spirometric parameters were measured in accordance with international recommendations. Results: We included a total of 72 pediatric PIBO patients. The mean pre- and post-bronchodilator values were clearly lower than the reference values for all parameters, especially FEF25‑75%. There were post-bronchodilator improvements. When measured as mean percent increases, FEV1 and FEF25-75%, improved by 11% and 20%, respectively. However, when the absolute values were calculated, the mean FEV1 and FEF25-75% both increased by only 0.1 L. We found that age at viral aggression, a family history of asthma, and allergy had no significant effects on bronchodilator responses. Conclusions: Pediatric patients with PIBO have peripheral airway obstruction that is responsive to treatment but is not completely reversible with a bronchodilator. The concept of PIBO as fixed, irreversible obstruction does not seem to apply to this population. Our data suggest that airway obstruction is variable in PIBO patients, a finding that could have major clinical implications.

Keywords: Bronchiolitis obliterans; Infection/complications; Airway obstruction; Bronchodilator agents.

Objective: To determine whether polymorphisms of the IL10 and IL17 genes are associated with severe asthma control and bronchodilator reversibility in children and adolescents with severe asthma. Methods: This was a cross-sectional study, nested within a prospective cohort study of patients with severe asthma. Two outcomes were evaluated: asthma control and bronchodilator reversibility. We extracted DNA from peripheral blood and genotyped three single nucleotide polymorphisms: rs3819024 and rs2275913 in the IL17A gene; and rs3024498 in the IL10 gene. For the association analyses, we performed logistic regression in three genetic models (allelic, additive, and dominant). Results: The rs3024498 C allele in the IL10 gene was associated with failure to achieve asthma control despite regular treatment (p = 0.02). However, the G allele of the IL17A rs3819024 polymorphism was associated with failure to respond to stimulation with a ß2 agonist. The rs2275913 polymorphism of the IL17A gene showed no relationship with asthma control or bronchodilator reversibility. Conclusions: In pediatric patients with severe asthma, the IL10 polymorphism appears to be associated with failure to achieve clinical control, whereas the IL17A polymorphism appears to be associated with a worse bronchodilator response. Knowledge of the involvement of these polymorphisms opens future directions for pharmacogenetic studies and for the implementation of individualized therapeutic management of severe asthma in pediatric patients.

Keywords: Polymorphism, genetic; Interleukin-10; Interleukin-17; Asthma.

Objective: To determine whether serum total IgE levels and total eosinophil counts have any relationship with the response to routine pharmacological treatment in patients with acute asthma. Methods: A cross-sectional study involving 162 patients with acute asthma. Serum total IgE levels, peripheral blood cell counts and eosinophil counts were determined. The treatment was adjusted for each patient according to the severity of asthma. Spirometry was performed at baseline and two weeks after the treatment. The patients were divided into two groups: high IgE (≥100 IU/mL) and low IgE (<100 IU/mL). We compared the two groups in terms of the relationships between baseline values and final values (percentage change) for the following parameters: FEV1, FVC, FEF25-75%, peripheral white blood cell counts and eosinophil counts. Results: There were no significant differences between the groups regarding the percentage changes of the studied parameters. Nor were there significant differences between the groups regarding FEV1, FVC, and FEF25-75% (% of the predicted values) at baseline. Conclusions: On the basis of these findings, we conclude that serum total IgE levels, peripheral white blood cell counts and eosinophil counts cannot predict the response to the pharmacological treatment of patients with acute asthma.

Keywords: Asthma/drug therapy; Eosinophils; Immunoglobulin E

Objective: The objective of this study was to evaluate the applicability of a modified version of the Saint George's Respiratory Questionnaire. The version evaluated elicits "agree" and "do not agree", rather than "yes" and "no", responses. The intention is to facilitate the comprehension of double-negative questions and to promote better recollection of symptoms by patients by shortening their symptom histories from 12 months to 3 months. Methods: A total of 30 clinically stable patients with chronic obstructive pulmonary disease were evaluated. The Saint George's Respiratory Questionnaire and the modified version of the same were administered 15 days apart. Results: All of the patients presented health-related alterations in their quality of life. Comparing mean scores between the two questionnaires, the greatest difference was seen in the Symptoms domain. No significant differences were found in any of the remaining domains or in the total scores. In a subsequent analysis, significant correlations between the two questionnaires were found in all domains: Symptoms (r = 0.71; p < 0.001); Activity (r = 0.75; p < 0.001); Impact (r = 0.73; p < 0.001) and Total (r = 0.86; p < 0.001). Conclusion: The modified version of the Saint George's Respiratory Questionnaire is as effective as the original in gauging quality of life. However, various symptoms recollection time frames should be investigated in order to determine which would be the best time frame to employ in the analysis.

Keywords: Pulmonary disease, chronic obstructive; Quality of life; Reproducibility of results; Cross-cultural comparison; Questionnaires