Requesting passive cooperation from the patient and supplying new parameters for the analysis of the ventilatory mechanics, the forced oscillations technique (FOT) has complementary characteristics to the classical methods of lung evaluation. In this work, a review of the principles of this technique is initially presented together with a discussion about its advantages and present limitations. The performance of the technique is compared to classical methods in the detection of breathing disorders. The main clinical applications reported previously in the literature, including the evaluation of the ventilatory mechanics in children, studies in neonates, monitoring of patients under mechanical ventilation, occupational medicine, and evaluation of respiratory sleep disturbances are reviewed and discussed. Based on this review and on the results obtained in studies made in their laboratory, the authors concluded that FOT could render a more detailed examination and facilitate the accomplishment of lung function tests under conditions in which traditional techniques are not appropriate.

Keywords: respiratory mechanics, oscillometry, respiratory function tests

Objective: To identify reference values for handgrip strength through a literature search and compare the agreement of reference values from Brazil with others for handgrip strength in a sample of COPD patients in Brazil, as well as to determine which set of reference values is more discriminative regarding differences in clinical characteristics between individuals with low handgrip strength and normal handgrip strength. Methods: To identify reference values for handgrip strength, a literature search was performed; a retrospective cross-sectional analysis of baseline-only data from two unrelated studies was then performed. Individuals were evaluated for handgrip strength, peripheral muscle strength, respiratory muscle strength, pulmonary function, body composition, exercise capacity, dyspnea, and functional status. Results: Of the 45 studies that were initially selected, 9 met the criteria for inclusion in the analysis, which included 99 COPD patients in Brazil (52% of whom were male with GOLD stage II-IV COPD). The prevalence of low handgrip strength varied across studies (from 9% to 55%), the set of reference values for handgrip strength in a sample of individuals in Brazil having classified 9% of the study sample as having low handgrip strength. The level of agreement between the reference values for a sample of individuals in Brazil and the other sets of reference values varied from weak to excellent. The reference values for a sample of individuals in Brazil showed the highest number of significantly different characteristics between individuals with low and normal handgrip strength. Conclusions: The level of agreement between national and international sets of reference values for handgrip strength varied from weak to excellent in COPD patients in Brazil. Reference values for handgrip strength with higher discriminative capacity are not necessarily those that identify more individuals as having low handgrip strength.

Keywords: Pulmonary disease, chronic obstructive; Hand strength; Muscle weakness; Muscle strength; Reference values.

Objective: To evaluate peripheral respiratory system resistance and reactance (Rrs and Xrs, respectively) in obese individuals. Methods: We recruited 99 individuals, dividing them into four groups by body mass index (BMI): < 30.0 kg/m2 (control, n = 31); 30.0-39.9 kg/m2 (obesity, n = 13); 40.0-49.9 kg/m2 (severe obesity, n = 28); and ≥ 50.0 kg/m2 (morbid obesity, n = 13). Using impulse oscillometry, we measured total Rrs, central Rrs, and Xrs. Peripheral Rrs was calculated as the difference between total Rrs and central Rrs. All subjects also underwent spirometry. Results: Of the 99 individuals recruited, 14 were excluded because they failed to perform forced expiratory maneuvers correctly during spirometry. The individuals in the severe obesity and morbid obesity groups showed higher peripheral Rrs and lower Xrs in comparison with those in the two other groups. Conclusions: Having a BMI ≥ 40 kg/m2 was associated with a significant increase in peripheral Rrs and with a decrease in Xrs.

Keywords: Obesity; Airway obstruction; Oscillometry; Respiratory function tests.

Objective: Manually assisted coughing (MAC) consists of a vigorous thrust applied to the chest at the beginning of a spontaneous expiration or of the expiratory phase of mechanical ventilation. Due to routine use of MAC in intensive care units, the objective of this study was to assess the effects of MAC on respiratory system mechanics in patients requiring full ventilatory support. Methods: We assessed 16 sedated patients on full ventilatory support (no active participation in ventilation). Respiratory system mechanics and oxyhemoglobin saturation were measured before and after MAC, as well as after endotracheal aspiration. Bilateral MAC was performed ten times on each patient, with three respiratory cycle intervals between each application. Results: Data analysis demonstrated a decrease in resistive pressure and respiratory system resistance, together with an increase in oxyhemoglobin saturation, after MAC combined with endotracheal aspiration. No evidence of alterations in peak pressures, plateau pressures or respiratory system compliance change was observed after MAC. Conclusions: The use of MAC alters respiratory system mechanics, increasing resistive forces by removing secretions. The technique is considered safe and efficacious for postoperative patients. Using MAC in conjunction with endotracheal aspiration provided benefits, achieving the proposed objective: the displacement and removal of airway secretions.

Keywords: Cough; Sputum; Respiratory mechanics; Respiration, artificial.

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: To compare the effects of voluntary breath stacking (VBS) and involuntary breath stacking (IBS) techniques on respiratory mechanics, lung function patterns, and inspiratory capacity in tracheostomized patients. Methods: This was a randomized crossover clinical trial involving 20 tracheostomized patients admitted to the ICU and submitted to the VBS and IBS techniques, in random order, with an interval of 5 h between each. Ten cycles of each technique were performed with an interval of 30 s between each cycle. In VBS, patients performed successive inspirations for up to 30 s through a one-way valve, whereas in IBS, successive slow insufflations were performed with a resuscitator bag until the pressure reached 40 cmH2O. Respiratory mechanics, inspiratory capacity, and the lung function pattern were evaluated before and after the interventions. Results: After IBS, there was an increase in static compliance (p = 0.007), which was also higher after IBS than after VBS (p = 0.03). There was no significant difference between the pre-VBS and post-VBS evaluations in terms of static compliance (p = 0.42). Inspiratory capacity was also greater after IBS than after VBS (2,420.7 ± 480.9 mL vs. 1,211.3 ± 562.8 mL; p < 0.001), as was airway pressure (38.3 ± 2.6 cmH2O vs. 25.8 ± 5.5 cmH2O; p < 0.001). There were no changes in resistance or lung function pattern after the application of either technique. Conclusions: In comparison with VBS, IBS promoted greater inspiratory capacity and higher airway pressure, resulting in an increase in static compliance.

Keywords: Mucociliary clearance; Respiratory care units; Respiratory mechanics; Physical therapy modalities.

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 test the applicability of a geometric model, adapted to the supine position, for the analysis of respiratory mechanics regarding changes in lateral thoracoabdominal areas in children with asthma. Methods: Nineteen children (mean age, 11.26 ± 1.28 years) performed isovolume maneuvers (IVMs) after maximal inspiration, followed by glottal closure and alternation of airflow between the abdominal and thoracic compartments. The maneuvers were recorded in a digital video camera placed perpendicularly to the movement plane, and the images of interest were selected. The geometric model was traced on each image based on surface landmarks of anatomical references. The traced areas were calculated using a computer program, and the results were converted into metric units (cm2) using a surface landmark of a known area. Relative contributions (RCs) of the subcompartments in relation to their original compartments and to the chest wall (CW) were calculated. Results: The model was based on 55 thoracic IVM images and 55 abdominal IVM images. Areas and subareas were compared between the maneuvers. There were significant differences in all subcompartments (p < 0.001). All of the RCs were significantly different for the CW (p < 0.001) but not for the ratios between the subcompartments and their original compartments. Conclusions: This geometric model, applied in children and adapted to the supine position, was effective in profiling changes in the thoracoabdominal silhouette during the IVMs, and the selected subdivisions were useful for the identification of areas contributing the most and the least to CW composition.

Keywords: Photogrammetry; Respiratory mechanics; Image processing, computer-assisted.

Worldwide, COPD is a major cause of morbidity and mortality. The clinical and functional manifestations of COPD result from lung injury occurring through various mechanisms, including oxidative stress, inflammation, protease-antiprotease imbalance and apoptosis. Oxidative stress is central to the pathogenesis of COPD, since it can directly damage lung structures and exacerbate the other mechanisms involved. The cellular and molecular events involved in such lung injury are believed to occur long before the clinical and functional expression of COPD. Although the use of bronchodilators is currently the principal treatment for COPD, bronchodilators have little or no effect on disease progression. A better understanding of the pathogenesis of COPD, together with renewed efforts in basic and clinical research, will allow the diagnosis of COPD at a pre-clinical stage and provide more appropriate monitoring of disease activity, as well as leading to the development of novel therapeutic agents that will effectively prevent the progression of the disease.

Keywords: Pulmonary disease, chronic obstructive; Oxidative stress; Oxidants; Antioxidants; Inflammation.

Objective: To compare the incidence and intensity of acute adverse effects and the variation in the temperature of facial skin by thermography after the use of noninvasive ventilation (NIV). Methods: We included 20 healthy volunteers receiving NIV via oronasal mask for 1 h. The volunteers were randomly divided into two groups according to the ventilatory mode: bilevel positive airway pressure (BiPAP) or continuous positive airway pressure (CPAP). Facial thermography was performed in order to determine the temperature of the face where it was in contact with the mask and of the nasal dorsum at various time points. After removal of the mask, the volunteers completed a questionnaire about adverse effects of NIV. Results: The incidence and intensity of acute adverse effects were higher in the individuals receiving BiPAP than in those receiving CPAP (16.1% vs. 5.6%). Thermographic analysis showed a significant cooling of the facial skin in the two regions of interest immediately after removal of the mask. The more intense acute adverse effects occurred predominantly among the participants in whom the decrease in the mean temperature of the nasal dorsum was lower (14.4% vs. 7.2%). The thermographic visual analysis of the zones of cooling and heating on the face identified areas of hypoperfusion or reactive hyperemia. Conclusions: The use of BiPAP mode was associated with a higher incidence and intensity of NIV-related acute adverse effects. There was an association between acute adverse effects and less cooling of the nasal dorsum immediately after removal of the mask. Cutaneous thermography can be an additional tool to detect adverse effects that the use of NIV has on facial skin.

Keywords: Masks; Noninvasive ventilation; Thermography.

Objective: Evaluate the impact of the instrument of the "Stratification by Degree of Clinical Severity and Abandonment Risk of Tuberculosis Treatment" (SRTB) on the tuberculosis outcome. Methods: This study was a pragmatic clinical trial involving patients with a confirmed diagnosis of tuberculosis treated at one of the 152 primary health care units in the city of Belo Horizonte, Brazil, between May of 2016 and April of 2017. Cluster areas for tuberculosis were identified, and the units and their respective patients were divided into intervention (use of SRTB) and nonintervention groups. Results: The total sample comprised 432 participants, 223 and 209 of whom being allocated to the nonintervention and intervention groups, respectively. The risk of treatment abandonment in the nonintervention group was significantly higher than was that in the intervention group (OR = 15.010; p < 0.001), regardless of the number of risk factors identified. Kaplan-Meier curves showed a hazard ratio of 0.0753 (p < 0.001). Conclusions: The SRTB instrument was effective in reducing abandonment of tuberculosis treatment, regardless of the number of risk factors for that. This instrument is rapid and easy to use, and can be adapted to different realities. Its application showed characteristics predisposing to a non-adherence to the treatment and established bases to mitigate its impact.

Keywords: Tuberculosis; Patient compliance; Risk factors; Treatment adherence.

Objective: To determine whether pulmonary mechanics are altered in mice with sepsis. Methods: A total of 40 Balb/c mice were divided into two groups: survival (n = 21) and pulmonary mechanics (n = 19). The survival group was divided into three subgroups: control (n = 7), sublethal (n = 7) and lethal (n = 7). The pulmonary mechanics group was also divided into three subgroups: control (n = 5), sublethal (n = 7) and lethal (n = 7). Sepsis was induced through cecal ligation and puncture, the latter varying in degree (sublethal or lethal). At eight hours after the intervention, pulmonary mechanics were measured through end-inflation occlusion. In the pulmonary mechanics group, the following variables were studied: total pressure, resistance, viscoelasticity, dynamic compliance and static compliance. The data obtained were analyzed using one-way ANOVA. Results: The data for the survival group indicate the efficacy of the model employed. There were no statistically significant differences among the pulmonary mechanics subgroups in terms of dynamic compliance, static compliance, total pressure, resistance or viscoelasticity. Conclusion: At eight hours after cecal ligation and puncture, there were no changes in the lung parenchyma, nor were any alterations observed in the viscous and viscoelastic components of the lung.

Keywords: Sepsis; Respiratory mechanics; Lung/injuries; Punctures/instrumentation; Respiratory distress syndrome, adult; Mice

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

The objective of the present review study was to present the principal applications of magnetic resonance imaging (MRI) of the chest, including the description of new techniques. Over the past decade, this method has evolved considerably because of the development of new equipment, including the simultaneous interconnection of phased-array multiple radiofrequency receiver coils and remote control of the table movement, in addition to faster techniques of image acquisition, such as parallel imaging and partial Fourier acquisitions, as well as the introduction of new contrast agents. All of these advances have allowed MRI to gain ground in the study of various pathologies of the chest, including lung diseases. Currently, MRI is considered the modality of choice for the evaluation of lesions in the mediastinum and in the chest wall, as well as of superior sulcus tumors. However, it can also facilitate the diagnosis of lung, pleural, and cardiac diseases, as well as of those related to the pulmonary vasculature. Pulmonary MRI angiography can be used in order to evaluate various pulmonary vascular diseases, and it has played an ever greater role in the study of thromboembolism. Because cardiac MRI allows morphological and functional assessment in the same test, it has also become part of the clinical routine in the evaluation of various cardiac diseases. Finally, the role of MRI has been extended to the identification and characterization of pulmonary nodules, the evaluation of airway diseases, and the characterization of pleural effusion.

Keywords: Magnetic resonance imaging; Thorax; Pulmonary medicine.

Objective: To evaluate the effect of the association of the breath stacking (BS) technique associated with routine physiotherapy on pulmonary function, lung volumes, maximum respiratory pressures, vital signs, peripheral oxygenation, thoracoabdominal mobility, and pain in the surgical incision in patients submitted to upper abdominal surgery during the postoperative period, as well as to analyze BS safety. Methods: This was a randomized clinical trial involving 34 patients divided into a control group (CG; n = 16), who underwent conventional physiotherapy only, and the BS group (BSG; n = 18), who underwent conventional physiotherapy and BS. Both groups performed two daily sessions from postoperative day 2 until hospital discharge. The primary outcomes were FVC and Vt. The safety of BS was assessed by the incidence of gastrointestinal, hemodynamic, and respiratory repercussions. Results: Although FVC significantly increased at hospital discharge in both groups, the effect was greater on the BSG. Significant increases in FEV1, FEV1/FVC ratio, PEF, and FEF25-75% occurred only in the BSG. There were also significant increases in Ve and Vt in the BSG, but not when compared with the CG values at discharge. MIP and MEP significantly increased in both groups, with a greater effect on the BSG. There was a significant decrease in RR, as well as a significant increase in SpO2 only in the BSG. SpO2 acutely increased after BS; however, no changes were observed in the degree of dyspnea, vital signs, or signs of respiratory distress, and no gastrointestinal and hemodynamic repercussions were observed. Conclusions: BS has proven to be safe and effective for recovering pulmonary function; improving lung volumes, maximum respiratory pressures, and peripheral oxygenation; and reducing respiratory work during the postoperative period after upper abdominal surgery.

Keywords: Abdomen/surgery; Pulmonary ventilation; Physical therapy modalities. (ClinicalTrials.gov identifier: NCT 04418700 [http://www.clinicaltrials.gov/])

Objective: To test the reliability, validity, and interpretability of the Brazilian version of the Clinical COPD Questionnaire (CCQ) in patients with COPD. Methods: Fifty patients with COPD completed the CCQ by interview on two occasions. At the first visit, the CCQ was administered twice, by two different raters, approximately 10 min apart; the patients also underwent spirometry and were administered the COPD Assessment Test, the modified Medical Research Council scale, and Saint George's Respiratory Questionnaire (SGRQ). At the second visit (1-2 weeks later), the CCQ was readministered. We tested the hypothesis that the CCQ total score would correlate positively with the total and domain SGRQ scores (r = 0.5). Results: Of the 50 patients, 30 (60%) were male. The mean age was 66 ± 8 years, and the mean FEV1 was 44.7 ± 17.9% of the predicted value. For all CCQ items, Cronbach's alpha coefficient (95% CI) was 0.93 (0.91-0.96). To analyze the interrater reliability and test-retest reliability of the CCQ, we calculated the two-way mixed effects model/single measure type intraclass correlation coefficient (0.97 [95% CI: 0.95-0.98] and 0.92 [95% CI: 0.86-0.95], respectively); the agreement standard error of measurement (0.65 for both); the smallest detectable change at the individual level (1.81 and 1.80, respectively) and group level (0.26 and 0.25, respectively); and the limits of agreement (-0.58 to 0.82 and -1.14 to 1.33, respectively). The CCQ total score correlated positively with all SGRQ scores (r = 0.70 for all). Conclusions: The Brazilian version of the CCQ showed an indeterminate measurement error, as well as satisfactory interrater/test-retest reliability and construct validity.

Keywords: Pulmonary disease, chronic obstructive; Health status; Patient reported outcome measures; Validation study.

Over the years, various recommendations have been made in pursuit of controlling resistance to antituberculosis drugs, especially multidrug resistance, in Brazil. Given the importance of standardizing those recommendations, the aim of this study was to describe the main recommendations of the Brazilian guidelines, primarily those related to the treatment and follow-up of cases of tuberculosis. From August through October of 2018, a document search was conducted via the websites of the Brazilian National Ministry of Health, the Brazilian National Tuberculosis Control Program, the JBP, and the Official Gazette of the Federal Republic of Brazil. Data were collected systematically by using a protocol designed specifically for this study. Documents published between 2004 and 2018 were selected. It was possible to understand and trace the history of the measures for the control of multidrug-resistant tuberculosis in Brazil from 2004, when the first documents related to the disease were published, up to 2018, when the second edition of the Brazilian National Guidelines for the Control of Tuberculosis was published. The contents of the documents were analyzed and grouped by case definition, diagnostic criteria, treatment, use of directly observed treatment; mechanisms of social protection for patients; data tools; and organization of care. This analysis allowed us to understand the efforts towards standardizing some measures in Brazil, not only identifying advances in the alignment with international prerogatives (case definition, incorporation of diagnostic technology, and treatment regimens) but also underscoring the need for greater clarity regarding the mechanisms of social protection and the organization of the care provided via the Brazilian health care system.

Keywords: Tuberculosis, multidrug-resistant; Organization and administration; Practice patterns, physicians'; Practice patterns, nurses'.

The mediastinum, made up by many organs and structures, comprises a wide range of affections, from simple cysts to low differentiated neoplasias and lymphomas. In their day-to-day activities, the diagnosis of these affections represent a real challenge to the pathologists. Furthermore, one of the main approaches to diagnosis includes mediastinoscopy. Therefore, the representation of the specimen for studies, as well as some artifacts to obtain the specimen, may pose some difficulty for a final diagnosis. This article will focus mainly on the problems faced to diagnose entities from the specimens obtained by mediatinoscopy in the surgical room, during the extraction of the material and at examination by freezing. The article will also update current criteria used to classify the tumors and the use of the immunohistochemistry to complement the diagnosis, criteria of invasion, and metastases. The purposes of this article are: recognize the main affections of the mediastinum, classify the main tumors, apply malignancy criteria, identify prognostic markers, and evaluate when there is need to establish a clinical, radiological and morphological correlation.

Keywords: Mediastinum. Mediastinum pathology. Prognostic markers.