Mechanisms of exercise limitation in patients with chronic hypersensitivity pneumonitis

Small airway and interstitial pulmonary involvements are prominent in chronic hypersensitivity pneumonitis (cHP). However, their roles on exercise limitation and the relationship with functional lung tests have not been studied in detail. Our aim was to evaluate exercise performance and its determinants in cHP. We evaluated maximal cardiopulmonary exercise testing performance in 28 cHP patients (forced vital capacity 57±17% pred) and 18 healthy controls during cycling. Patients had reduced exercise performance with lower peak oxygen production (16.6 (12.3-19.98) mL·kg-1·min-1versus 25.1 (16.9-32.0), p=0.003), diminished breathing reserve (% maximal voluntary ventilation) (12 (6.4-34.8)% versus 41 (32.7-50.8)%, p<0.001) and hyperventilation (minute ventilation/carbon dioxide production slope 37±5 versus 31±4, p<0.001). All patients presented oxygen desaturation and augmented Borg dyspnoea scores (8 (5-10) versus 4 (1-7), p=0.004). The prevalence of dynamic hyperinflation was found in only 18% of patients. When comparing cHP patients with normal and low peak oxygen production (<84% pred, lower limit of normal), the latter exhibited a higher minute ventilation/carbon dioxide production slope (39±5.0 versus 34±3.6, p=0.004), lower tidal volume (0.84 (0.78-0.90) L versus 1.15 (0.97-1.67) L, p=0.002), and poorer physical functioning score on the Short form-36 health survey. Receiver operating characteristic curve analysis showed that reduced lung volumes (forced vital capacity %, total lung capacity % and diffusing capacity of the lung for carbon dioxide %) were high predictors of poor exercise capacity. Reduced exercise capacity was prevalent in patients because of ventilatory limitation and not due to dynamic hyperinflation. Reduced lung volumes were reliable predictors of lower performance during exercise

A“Dirty” Footprint: Macroinvertebrate diversity in Amazonian Anthropic Soils

International audienceAmazonian rainforests, once thought to be pristine wilderness, are increasingly known to have been widely inhabited, modified, and managed prior to European arrival, by human populations with diverse cultural backgrounds. Amazonian Dark Earths (ADEs) are fertile soils found throughout the Amazon Basin, created by pre-Columbian societies with sedentary habits. Much is known about the chemistry of these soils, yet their zoology has been neglected. Hence, we characterized soil fertility, macroinvertebrate communities, and their activity at nine archeological sites in three Amazonian regions in ADEs and adjacent reference soils under native forest (young and old) and agricultural systems. We found 673 morphospecies and, despite similar richness in ADEs (385 spp.) and reference soils (399 spp.), we identified a tenacious pre-Columbian footprint, with 49% of morphospecies found exclusively in ADEs. Termite and total macroinvertebrate abundance were higher in reference soils, while soil fertility and macroinvertebrate activity were higher in the ADEs, and associated with larger earthworm quantities and biomass. We show that ADE habitats have a unique pool of species, but that modern land use of ADEs decreases their populations, diversity, and contributions to soil functioning. These findings support the idea that humans created and sustained high-fertility ecosystems that persist today, altering biodiversity patterns in Amazonia

Study of work of breathing at rest and during exercise in individuals with chronic obstructive pulmonary disease, interstitial lung diseases and in a healthy control group

Introdução: A DPOC e as DPIFs são duas importantes doenças respiratórias crônicas que se caracterizam por aumento na dispneia, intolerância aos esforços e prejuízo da qualidade de vida. As causas desses prejuízos são multifatoriais, sendo que as ações dos músculos inspiratórios e expiratórios e os componentes do trabalho ventilatório são de fundamental importância, porém ainda não são completamente compreendidos. Objetivos: O objetivo principal deste estudo foi avaliar o trabalho respiratório (WOB), e o grau de recrutamento da musculatura inspiratória e expiratória em dois grupos de doenças respiratórias, DPOC e DPIF, no repouso e durante o exercício. Metodologia: Trata-se de um estudo transversal envolvendo 3 grupos, DPOC, DPIF e indivíduos controle saudáveis (n=20 cada grupo). Foram realizadas avaliações de dispneia (mMRC), qualidade de vida (SGRQ) e prova de função pulmonar. Foram mensuradas no repouso: 1) Medidas de força muscular respiratória volitivas não invasivas; 2) Pressão esofágica (PEs), Pressão Gástrica (PGa) e Pressão transdiafragmática (PDI); 3) Medidas de força muscular volitiva invasiva; 4) Medidas de força muscular não volitiva através de estimulação magnética; 5) Eletromiografia de superfície (EMG) dos músculos acessórios inspiratórios (escaleno e ECM) e expiratórios (obliquo externo). A seguir foi realizado um teste de esforço cardiopulmonar (TECP) incremental em bicicleta ergométrica. Com os dados de mecânica respiratória foram avaliados o trabalho ventilatório (WOB total) e seus componentes isolados (elástico, resistivo e expiratório) Resultados: Os grupos de doenças respiratórias crônicas não apresentaram fraqueza muscular nas avaliações estáticas. Contudo, apresentaram baixo desempenho no teste de esforço e dispneia como sintoma limitante. Apresentaram também aumento significativo da PDI durante o esforço, sendo que na DPIF acontece maior aumento na PEs e baixo incremento na PGa, e na DPOC houve aumento significativo da PGa durante o esforço. Na DPIF ocorre maior recrutamento dos músculos acessórios inspiratórios, já na DPOC além do recrutamento inspiratório também foi observado alto recrutamento abdominal. Em ambas as doenças foi possível verificar ineficiência neuromecânica da ventilação. O trabalho respiratório e seus componentes são distintos nas diferentes doenças respiratórias crônicas. Na DPOC existe aumento considerável do WOB resistido e expiratório durante o esforço, enquanto na DPIF o WOB elástico é responsável pela maior porcentagem do trabalho total. O esforço muscular e o trabalho ventilatório se correlacionaram com maior grau de dispneia nessas doenças. Conclusões: A atividade precoce e aumentada dos músculos respiratórios e os componentes do trabalho respiratório contribuiram significativamente para a dispneia, a intolerância ao exercício e a ineficiência neuromecânica da ventilação na DPOC e na DPIF. Existem importantes diferenças no mecanismo de geração de força diafragmática entre essas doenças. Os comprometimentos observados podem não ser detectáveis em testes de força estática ao repousoIntroduction: Chronic obstructive pulmonary disease (COPD) and interstitial lung diseases (ILDs) are two important chronic respiratory diseases that have as common characteristics dyspnea, exercise intolerance and impaired quality of life. The role of inspiratory and expiratory muscle action and work of breathing components, although very important, remains incompletely understood. Objectives: The main objective of this study was to evaluate the work of breathing (WOB), and the degree of recruitment of the inspiratory and expiratory muscles in two groups of chronic respiratory diseases, COPD and ILDs, at rest and during a incremental cycle exercise. Methods: We compared sensory-mechanical relationships in patients with COPD, ILDs and healthy control subjects (n=20 each). Dyspnea (mMRC), quality of life (SGRQ) and pulmonary function test were performed. We evaluate at rest: 1) Non-invasive volitional respiratory muscle strength; 2) Esophageal Pressure (PEs), Gastric Pressure (PGa) and Transdiaphragmatic Pressure (PDI) measured through the passage of balloons; 3) Invasive volitional muscle strength; 4) Non-volitional invasive muscle strength through magnetic stimulation; 5) Surface electromyography of accessory inspiratory (scalene and ECM) and expiratory (external oblique) muscles. Then, subjects performed an incremental cycle cardiopulmonary exercise testing (CPET). With the respiratory mechanics data, the work of breathing (total WOB) and its isolated components (elastic, resistive and expiratory) were evaluated. Results: Chronic respiratory diseases did not show muscle weakness in the static evaluations. However, they showed poor performance in the exercise test and dyspnea as a limiting symptom. They also showed a significant increase in PDI during effort, and in ILDs there is a greater increase in PEs and a low increase in PGa, and in COPD there is a significant increase in PGa during effort. In ILDs, there is greater recruitment of accessory inspiratory muscles, whereas in COPD, in addition to inspiratory recruitment, high abdominal recruitment was also observed. In both diseases it was possible to verify neuromechanical inefficiency of ventilation compared to healthy control subjects. The work of breathing and its components are different in different chronic respiratory diseases. In COPD, there is a considerable increase in resistive and expiratory WOB during exertion, while in DPIF, elastic WOB is responsible for the highest percentage of total WOB. Muscular effort and work of breathing correlated with a higher dyspnea in these diseases. Conclusions: Early and increased activity of the respiratory muscles and changes in the work of breathing components significantly contribute to dyspnea, exercise intolerance, and neuromechanical inefficiency of ventilation in COPD and ILDs. There are important differences in the mechanism of generation of diaphragmatic force between these diseases. The observed impairments may not be detectable on static strength tests at res

Diagnostic methods to assess inspiratory and expiratory muscle strength

Impairment of (inspiratory and expiratory) respiratory muscles is a common clinical finding, not only in patients with neuromuscular disease but also in patients with primary disease of the lung parenchyma or airways. Although such impairment is common, its recognition is usually delayed because its signs and symptoms are nonspecific and late. This delayed recognition, or even the lack thereof, occurs because the diagnostic tests used in the assessment of respiratory muscle strength are not widely known and available. There are various methods of assessing respiratory muscle strength during the inspiratory and expiratory phases. These methods are divided into two categories: volitional tests (which require patient understanding and cooperation); and non-volitional tests. Volitional tests, such as those that measure maximal inspiratory and expiratory pressures, are the most commonly used because they are readily available. Non-volitional tests depend on magnetic stimulation of the phrenic nerve accompanied by the measurement of inspiratory mouth pressure, inspiratory esophageal pressure, or inspiratory transdiaphragmatic pressure. Another method that has come to be widely used is ultrasound imaging of the diaphragm. We believe that pulmonologists involved in the care of patients with respiratory diseases should be familiar with the tests used in order to assess respiratory muscle function.Therefore, the aim of the present article is to describe the advantages, disadvantages, procedures, and clinical applicability of the main tests used in the assessment of respiratory muscle strength

Diagnostic methods to assess inspiratory and expiratory muscle strength

Impairment of (inspiratory and expiratory) respiratory muscles is a common clinical finding, not only in patients with neuromuscular disease but also in patients with primary disease of the lung parenchyma or airways. Although such impairment is common, its recognition is usually delayed because its signs and symptoms are nonspecific and late. This delayed recognition, or even the lack thereof, occurs because the diagnostic tests used in the assessment of respiratory muscle strength are not widely known and available. There are various methods of assessing respiratory muscle strength during the inspiratory and expiratory phases. These methods are divided into two categories: volitional tests (which require patient understanding and cooperation); and non-volitional tests. Volitional tests, such as those that measure maximal inspiratory and expiratory pressures, are the most commonly used because they are readily available. Non-volitional tests depend on magnetic stimulation of the phrenic nerve accompanied by the measurement of inspiratory mouth pressure, inspiratory esophageal pressure, or inspiratory transdiaphragmatic pressure. Another method that has come to be widely used is ultrasound imaging of the diaphragm. We believe that pulmonologists involved in the care of patients with respiratory diseases should be familiar with the tests used in order to assess respiratory muscle function.Therefore, the aim of the present article is to describe the advantages, disadvantages, procedures, and clinical applicability of the main tests used in the assessment of respiratory muscle strength

Monitoring.

<p>A) Optoelectronic plethysmography (OEP): retro-reflective markers separating both the upper rib cage (RCp) and abdomen (AB) compartments. B) Respiratory Inductive plethysmography (RIP): elastic bands positioned on RCp and AB compartments. C) RCp and AB movement during respiratory cicles.</p

Thoracoabdominal asynchrony: Two methods in healthy, COPD, and interstitial lung disease patients

<div><p>Background</p><p>Thoracoabdominal asynchrony is the nonparallel motion of the ribcage and abdomen. It is estimated by using respiratory inductive plethysmography and, recently, using optoelectronic plethysmography; however the agreement of measurements between these 2 techniques is unknown. Therefore, the present study compared respiratory inductive plethysmography with optoelectronic plethysmography for measuring thoracoabdominal asynchrony to see if the measurements were similar or different.</p><p>Methods</p><p>27 individuals (9 healthy subjects, 9 patients with interstitial lung disease, and 9 with chronic obstructive pulmonary disease performed 2 cycle ergometer tests with respiratory inductive plethysmography or optoelectronic plethysmography in a random order. Thoracoabdominal asynchrony was evaluated at rest, and at 50% and 75% of maximal workload between the superior ribcage and abdomen using a phase angle.</p><p>Results</p><p>Thoracoabdominal asynchrony values were very similar in both approaches not only at rest but also with exercise, with no statistical difference. There was a good correlation between the methods and the Phase angle values were within the limits of agreement in the Bland-Altman analysis.</p><p>Conclusion</p><p>Thoracoabdominal asynchrony measured by optoelectronic plethysmography and respiratory inductive plethysmography results in similar values and has a satisfactory agreement at rest and even for different exercise intensities in these groups.</p></div