Diaphragm Ultrasound in Critically Ill Patients on Mechanical Ventilation-Evolving Concepts.

Mechanical ventilation (MV) is a life-saving respiratory support therapy, but MV can lead to diaphragm muscle injury (myotrauma) and induce diaphragmatic dysfunction (DD). DD is relevant because it is highly prevalent and associated with significant adverse outcomes, including prolonged ventilation, weaning failures, and mortality. The main mechanisms involved in the occurrence of myotrauma are associated with inadequate MV support in adapting to the patient's respiratory effort (over- and under-assistance) and as a result of patient-ventilator asynchrony (PVA). The recognition of these mechanisms associated with myotrauma forced the development of myotrauma prevention strategies (MV with diaphragm protection), mainly based on titration of appropriate levels of inspiratory effort (to avoid over- and under-assistance) and to avoid PVA. Protecting the diaphragm during MV therefore requires the use of tools to monitor diaphragmatic effort and detect PVA. Diaphragm ultrasound is a non-invasive technique that can be used to monitor diaphragm function, to assess PVA, and potentially help to define diaphragmatic effort with protective ventilation. This review aims to provide clinicians with an overview of the relevance of DD and the main mechanisms underlying myotrauma, as well as the most current strategies aimed at minimizing the occurrence of myotrauma with special emphasis on the role of ultrasound in monitoring diaphragm function.

Persistence of symptoms and return to work after hospitalization for COVID-19.

Many patients hospitalized with COVID-19 were unable to return to work or their return was delayed due to their health condition. The aim of this observational study was to evaluate the impact of moderate-to-severe and critical COVID-19 infection on persistence of symptoms and return to work after hospital discharge. In this study, two thirds of hospitalized patients with pulmonary involvement reported persistence of symptoms six months after COVID-19 infection, such as memory loss (45.5%), myalgia (43.9%), fatigue (39.4%), and dyspnea (25.8%), and 50% slowly returned to work, with repercussions due to fatigue and/or loss of energy.

Persistence of symptoms and return to work after hospitalization for COVID-19 / Persistência de sintomas e retorno ao trabalho após hospitalização por COVID-19

ABSTRACT Many patients hospitalized with COVID-19 were unable to return to work or their return was delayed due to their health condition. The aim of this observational study was to evaluate the impact of moderate-to-severe and critical COVID-19 infection on persistence of symptoms and return to work after hospital discharge. In this study, two thirds of hospitalized patients with pulmonary involvement reported persistence of symptoms six months after COVID-19 infection, such as memory loss (45.5%), myalgia (43.9%), fatigue (39.4%), and dyspnea (25.8%), and 50% slowly returned to work, with repercussions due to fatigue and/or loss of energy.

RESUMO Muitos pacientes hospitalizados com COVID-19 não puderam retornar ao trabalho ou seu retorno foi atrasado devido ao seu estado de saúde. O objetivo deste estudo observacional foi avaliar o impacto da infecção moderada a grave ou crítica por COVID-19 na persistência dos sintomas e no retorno ao trabalho após a alta hospitalar. Neste estudo, dois terços dos pacientes hospitalizados com acometimento pulmonar relataram persistência dos sintomas seis meses após a infecção por COVID-19, como perda de memória (45,5%), mialgia (43,9%), fadiga (39,4%) e dispneia (25,8%), e 50% retornaram lentamente ao trabalho, com repercussões devido à fadiga e/ou perda de energia.

Dynamic hyperinflation induced by the 6-minute pegboard and ring test in hospitalized patients with exacerbated COPD.

BACKGROUND: The six-minute pegboard and ring test (6-PBRT) has been used to evaluate functional capacity of the upper limbs in stable chronic obstructive pulmonary disease (COPD) patients. To the best of our knowledge, no studies have evaluated dynamic hyperinflation (DH) during exercise with upper limbs in the hospital setting. The aim of this study was to evaluate physiological responses and DH induced by 6-PBRT in hospitalized patients with acute exacerbation of COPD (AECOPD). METHODS: A cross-sectional study was conducted in a tertiary hospital enrolling patients who were hospitalized due to AECOPD. All included participants underwent an evaluation of lung function and 6-PBRT when they reached minimum clinical criteria. Ventilatory and hemodynamics parameters were monitored during 6-PBRT and until 6 minutes of rest after the test. Symptoms of dyspnea and upper limb fatigue were also measured. RESULTS: Eighteen patients (71.3±5.1 years) with a mean FEV1 of 43.2±18.3% were included in the study (11 females). Prevalence of DH after 6-PBRT was 50% (considering the drop of 150 ml or 10% of inspiratory capacity, immediately after the end of the test). There was a significant increase in respiratory rate, minute volume, dyspnea, and upper limb fatigue after the end of 6-PBRT (p<0.05). Dyspnea recovered more precociously than the perception of fatigue, being reestablished within four minutes of rest. An increase in heart rate, systolic and diastolic blood pressures was also induced by 6-PBRT (p<0.05), requiring 6 minutes of recovery to return to baseline. No adverse events were observed during 6-PBRT. We concluded that 6-PBRT induces physiological changes during its execution, at safe levels, requiring a maximum of 6 minutes for recovery. Finally, the test proved to be safe and applicable for patients hospitalized due to AECOPD.

Diaphragmatic ultrasound: a review of its methodological aspects and clinical uses.

The diaphragm is the main muscle of respiration, acting continuously and uninterruptedly to sustain the task of breathing. Diaphragmatic dysfunction can occur secondary to numerous pathological conditions and is usually underdiagnosed in clinical practice because of its nonspecific presentation. Although several techniques have been used in evaluating diaphragmatic function, the diagnosis of diaphragmatic dysfunction is still problematic. Diaphragmatic ultrasound has gained importance because of its many advantages, including the fact that it is noninvasive, does not expose patients to radiation, is widely available, provides immediate results, is highly accurate, and is repeatable at the bedside. Various authors have described ultrasound techniques to assess diaphragmatic excursion and diaphragm thickening in the zone of apposition. Recent studies have proposed standardization of the methods. This article reviews the usefulness of ultrasound for the evaluation of diaphragmatic function, addressing the details of the technique, the main findings, and the clinical applications.

Forced Oscillation Technique and Small Airway Involvement in Chronic Hypersensitivity Pneumonitis / Técnica de la oscilación forzada e implicación de las vías aéreas pequeñas en la neumonitis por hipersensibilidad crónica

Objective: Hypersensitivity pneumonitis (HP) is an interstitial lung disease caused by the inhalation of specific organic antigens or low-molecular weight substances in genetically susceptible individuals. Although small airway involvement is prominent in patients with chronic HP, conventional pulmonary function tests (PFTs) are relatively insensitive to identify it. Thus, the authors aimed to evaluate resistance (R5) and reactance (X5) values at 5Hz on inspiration, expiration, and whole breath, as well as small airway resistance (R5-19) values using a forced oscillation technique (FOT) in patients with chronic HP, and their responses after bronchodilator. In addition, R5 and X5 values according to the presence or absence of mosaic attenuation on computed tomography (CT) were compared. Methods: PFTs with plethysmography, diffusing capacity of the lungs for carbon monoxide (DLCO) and FOT measurements were performed pre-bronchodilator and post-bronchodilator. High-resolution CT was performed at the same visit, and classified according to the presence or absence of mosaic attenuation. R5 and X5 values were then compared according to the presence or absence of mosaic attenuation on CT. Results: Twenty-eight patients with chronic HP (57.1% female; mean age, 56 ± 11.5 years; mean forced vital capacity 57 ± 17% predicted) were evaluated. All patients had low X5 values, reflecting lower lung compliance, and only three (8%) demonstrated elevated R5 (whole-breath) values. No patients exhibited bronchodilator response in R5, X5 and R5-19 values. In patients who exhibited greater extension of mosaic attenuation (n = 11), R5 and X5 values could not discriminate those with a greater presence of these areas on CT. Conclusions: The results suggest that FOT does not help to additionally characterise concomitant small airway involvement in patients with chronic fibrotic HP who demonstrate restrictive ventilatory pattern in conventional PFTs. Nevertheless, FOT appeared to better characterise decreased lung compliance due to fibrosis through X5. Bronchodilator therapy did not appear to induce an acute response in chronic HP patients with restrictive disease. The precise role of FOT in subacute HP and obstructive chronic HP, therefore, must be evaluated

Objetivo: La neumonitis por hipersensibilidad (HP) es una enfermedad pulmonar intersticial causada por la inhalación de antígenos orgánicos específicos o sustancias de bajo peso molecular en individuos genéticamente susceptibles. Aunque la implicación de las vías aéreas pequeñas es típica en pacientes con HP crónica, a las pruebas habituales de función pulmonar (PFP) les falta sensibilidad para detectarla. El objetivo fue evaluar los valores de resistencia (R5) y de reactancia (X5) a 5Hz durante la inspiración, la espiración y el ciclo completo, así como los valores de resistencia de las vías aéreas pequeñas y las respuestas tras broncodilatador. Para ello se utilizó la técnica de oscilación forzada (TOF) en pacientes con HP crónica. Además, se comprobaron los valores R5 y X5, de acuerdo con la presencia o ausencia de patrones de atenuación en mosaico mediante tomografía computarizada (TC). Métodos: Se evaluaron las PFP con pletismografía, la capacidad de difusión pulmonar para el monóxido de carbono (DLCO) y la TOF antes y después de broncodilatador (pre- y posbroncodilatador, respectivamente). La TC de alta resolución se realizó en la misma visita, y los resultados se clasificaron en función de la presencia o ausencia de patrones de atenuación en mosaico. Resultados: Se evaluaron 28 pacientes con HP crónica (57,1% mujeres; edad media: 56 ± 11,5 años; capacidad vital forzada media estimada: 57 ± 17%). Todos los pacientes tuvieron valores X5 bajos, indicativo de una distensibilidad pulmonar baja, y solo 3 (8%) presentaron valores elevados de R5 (respiración completa). Ningún paciente exhibió respuesta broncodilatadora en valores R5, X5 y R5-19. Los valores de R5 y X5 no permitieron discriminar a aquellos pacientes que presentaron patrón de atenuación en mosaico extenso en la TC (n = 11). Conclusiones: Los resultados sugieren que la TOF no proporciona información extra en la caracterización de la implicación concomitante de las vías aéreas pequeñas en pacientes con HP crónica que presentan patrones ventilatorios restrictivos en PFP convencionales. Sin embargo, la TOF parece permitir una mejor caracterización de la disminución de la distensibilidad pulmonar debido a fibrosis a través del valor X5. La terapia broncodilatadora no indujo respuesta aguda en pacientes con HP crónica y enfermedad restrictiva. Por tanto, se debe evaluar el papel específico de la TOF en la HP subaguda y la HP obstructiva crónica

Quanto tempo de oclusão é necessário para avaliar a pressão inspiratória máxima pelo método da válvula expiratória unidirecional em sujeitos sem via aérea artificial? / ¿Cuánto tiempo de oclusión es necesario para evaluar la presión inspiratoria máxima por el método de la válvula espiratoria unidireccional en sujetos sin vía aérea artificial? / How much occlusion time is necessary to assess maximal inspiratory pressure by the unidirectional expiratory valve method in subjects without artificial airway?

RESUMO O objetivo desse estudo foi determinar o tempo de oclusão necessário para avaliar a pressão inspiratória máxima (PIMáx) obtida pelo método da válvula expiratória unidirecional em sujeitos sem via aérea artificial. Foram avaliados 31 sujeitos, com idade entre 18 e 60 anos. A PIMáx foi avaliada pelo método convencional (PIMáxconv) e pelo método da válvula expiratória unidirecional (PIMáxuni), sendo a ordem de avaliação definida por meio de sorteio. Para a medida da PIMáxuni, um manovacuômetro digital foi acoplado a uma válvula expiratória unidirecional e máscara orofacial por 20 segundos de oclusão. Nesse período, todos os sujeitos foram encorajados a realizar esforços inspiratórios máximos. Para definir a ótima duração da manobra, o tempo de esforço foi dividido a cada intervalo de 5 segundos (0-5s, 0-10s, 0-15s, 0-20s). Os intervalos de tempo para obtenção da PIMáxuni foram comparados por meio do teste de ANOVA One-way. Para comparação das médias dos valores de PIMáxconv e PIMáxuni, foi utilizado o teste t de Student. O nível de significância foi de 5%. A média dos valores da PIMáxconv foi de -102,5±23,9 cmH2O, enquanto que a PIMáxuni foi de -117,3±24,8 cmH2O (p<0,001). O valor absoluto máximo da PIMáxuni foi alcançado dentro do intervalo de 0-20 segundos, que foi significativamente superior ao valor absoluto máximo obtido nos primeiros 5 segundos (p=0,036). O tempo de oclusão necessário para avaliar a PIMáx pelo método da válvula expiratória unidirecional em sujeitos colaborativos sem via aérea artificial deve ser de pelo menos 20 segundos.

RESUMEN Este estudio busca determinar cuánto tiempo de oclusión es necesario para obtener la presión inspiratoria máxima (PIMáx) por medio del método de la válvula espiratoria unidireccional en individuos sin vía aérea artificial. Se evaluaron 31 sujetos de entre 18 y 60 años de edad. La PIMáx se evaluó mediante el método estándar (PIMáxest) y el método de válvula espiratoria unidireccional (PIMáxuni), siendo que el orden de evaluación se estableció por medio de un sorteo. Para el PIMáxuni, un manovacuómetro digital se ha conectado a una válvula espiratoria unidireccional y una máscara orofacial durante 20 segundos de oclusión. Durante este período, se alentó a los individuos a hacer esfuerzos respiratorios máximos. Para definir la óptima duración de la maniobra, el tiempo de esfuerzo se dividió en intervalos de cinco segundos (0-5s, 0-10s, 0-15s, 0-20s). Los intervalos del tiempo para el PIMáxuni se compararon mediante la prueba ANOVA one-way. Las medias de los valores de PIMáxest y de PIMáxuni se compararon mediante la prueba pareada t de Student. El nivel de significancia se estableció en el 5%. La media de los valores de PIMáxest (-102,5±23,9 cmH2O) presentó una diferencia estadísticamente significativa en comparación con la media de los valores de PIMáxuni (-117,3±24,8 cmH2O, p<0,001). El valor absoluto máximo obtenido de PIMáxuni estaba dentro del intervalo de 0-20 segundos, que fue significativamente superior del valor absoluto máximo durante los primeros 5 segundos (p=0,036). El tiempo de oclusión necesario para registrar la PIMáx por el método de válvula espiratoria unidireccional en individuos colaborativos sin vía aérea artificial debe ser de al menos 20 segundos.

ABSTRACT The aim of this study was to determine how much occlusion time is necessary to obtain maximal inspiratory pressure (MIP) by the unidirectional expiratory valve method in subjects without artificial airway. Thirty-one subjects aged 18-60 years were evaluated. MIP was evaluated by the standard method (MIPstan) and by the unidirectional expiratory valve method MIPuni, with the order of evaluation determined randomly by lot. For MIPuni measurement, a digital vacuum manometer was attached to a unidirectional expiratory valve and an orofacial mask for 20 seconds of occlusion. During this period, all subjects were encouraged to make maximal respiratory efforts. To define the optimum duration of the maneuver, the 20 seconds of effort were partitioned at every five-second interval (0-5s, 0-10s, 0-15s, 0-20s). The time intervals for obtaining MIPuni were compared with the one-way ANOVA test. The mean values of the standard method and the unidirectional expiratory valve method were compared using the paired Student's t-test. The significance level was established at 5%. The mean values for the MIPstan (-102.5±23.9 cmH2O) presented a statistically significant difference as compared to the mean values for MIPuni (-117.3±24.8 cmH2O; p<0.001). Maximal peak values for MIPuni were achieved within the 20-second time window, which differed significantly from the peak values obtained during the first five seconds (p=0.036). The occlusion time necessary to record MIP by the unidirectional expiratory valve method in collaborative subjects without artificial airway should be of at least 20 seconds.

Impact of thoracic radiotherapy on respiratory function and exercise capacity in patients with breast cancer / Impacto da radioterapia torácica na função respiratória e capacidade de exercício em pacientes com câncer de mama

ABSTRACT Objective: To evaluate the impact of thoracic radiotherapy on respiratory function and exercise capacity in patients with breast cancer. Methods: Breast cancer patients in whom thoracic radiotherapy was indicated after surgical treatment and chemotherapy were submitted to HRCT, respiratory evaluation, and exercise capacity evaluation before radiotherapy and at three months after treatment completion. Respiratory muscle strength testing, measurement of chest wall mobility, and complete pulmonary function testing were performed for respiratory evaluation; cardiopulmonary exercise testing was performed to evaluate exercise capacity. The total radiotherapy dose was 50.4 Gy (1.8 Gy/fraction) to the breast or chest wall, including supraclavicular lymph nodes (SCLN) or not. Dose-volume histograms were calculated for each patient with special attention to the ipsilateral lung volume receiving 25 Gy (V25), in absolute and relative values, and mean lung dose. Results: The study comprised 37 patients. After radiotherapy, significant decreases were observed in respiratory muscle strength, chest wall mobility, exercise capacity, and pulmonary function test results (p < 0.05). DLCO was unchanged. HRCT showed changes related to radiotherapy in 87% of the patients, which was more evident in the patients submitted to SCLN irradiation. V25% significantly correlated with radiation pneumonitis. Conclusions: In our sample of patients with breast cancer, thoracic radiotherapy seemed to have caused significant losses in respiratory and exercise capacity, probably due to chest wall restriction; SCLN irradiation represented an additional risk factor for the development of radiation pneumonitis.

RESUMO Objetivo: Avaliar o impacto da radioterapia torácica na função respiratória e capacidade de exercício em pacientes com câncer de mama. Métodos: Pacientes com câncer de mama com indicação de radioterapia torácica após tratamento cirúrgico e quimioterápico foram submetidas a TCAR, avaliação respiratória e avaliação da capacidade de exercício antes da radioterapia torácica e três meses após o término do tratamento. Foram realizados teste de força muscular respiratória, medição da mobilidade torácica e prova de função pulmonar completa para a avaliação respiratória; realizou-se teste de exercício cardiopulmonar para avaliar a capacidade de exercício. A dose total de radioterapia foi de 50,4 Gy (1,8 Gy/fração) na mama ou na parede torácica, incluindo ou não a fossa supraclavicular (FSC). Histogramas dose-volume foram calculados para cada paciente com especial atenção para o volume pulmonar ipsilateral que recebeu 25 Gy (V25), em números absolutos e relativos, e a dose pulmonar média. Resultados: O estudo incluiu 37 pacientes. Após a radioterapia, observou-se diminuição significativa da força muscular respiratória, mobilidade torácica, capacidade de exercício e resultados da prova de função pulmonar (p < 0,05). A DLCO permaneceu inalterada. A TCAR mostrou alterações relacionadas à radioterapia em 87% das pacientes, o que foi mais evidente nas pacientes submetidas à irradiação da FSC. O V25% correlacionou-se significativamente com a pneumonite por radiação. Conclusões: Em nossa amostra de pacientes com câncer de mama, a radioterapia torácica parece ter causado perdas significativas na capacidade respiratória e de exercício, provavelmente por causa da restrição torácica; a irradiação da FSC representou um fator de risco adicional para o desenvolvimento de pneumonite por radiação.

Computed tomography in hypersensitivity pneumonitis: main findings, differential diagnosis and pitfalls.

INTRODUCTION: Hypersensitivity pneumonitis (HP) is a disease with variable clinical presentation in which inflammation in the lung parenchyma is caused by the inhalation of specific organic antigens or low molecular weight substances in genetically susceptible individuals. Alterations of the acute, subacute and chronic forms may eventually overlap, and the diagnosis based on temporality and presence of fibrosis (acute/inflammatory HP vs. chronic HP) seems to be more feasible and useful in clinical practice. Differential diagnosis of chronic HP with other interstitial fibrotic diseases is challenging due to the overlap of the clinical history, and the functional and imaging findings of these pathologies in the terminal stages. Areas covered: This article reviews the essential features of HP with emphasis on imaging features. Moreover, the main methodological limitations of high-resolution computed tomography (HRCT) interpretation are discussed, as well as new perspectives with volumetric quantitative CT analysis as a useful tool for retrieving detailed and accurate information from the lung parenchyma. Expert commentary: Mosaic attenuation is a prominent feature of this disease, but air trapping in chronic HP seems overestimated. Quantitative analysis has the potential to estimate the involvement of the pulmonary parenchyma more accurately and could correlate better with pulmonary function results.

Impact of thoracic radiotherapy on respiratory function and exercise capacity in patients with breast cancer.

OBJECTIVE: To evaluate the impact of thoracic radiotherapy on respiratory function and exercise capacity in patients with breast cancer. METHODS: Breast cancer patients in whom thoracic radiotherapy was indicated after surgical treatment and chemotherapy were submitted to HRCT, respiratory evaluation, and exercise capacity evaluation before radiotherapy and at three months after treatment completion. Respiratory muscle strength testing, measurement of chest wall mobility, and complete pulmonary function testing were performed for respiratory evaluation; cardiopulmonary exercise testing was performed to evaluate exercise capacity. The total radiotherapy dose was 50.4 Gy (1.8 Gy/fraction) to the breast or chest wall, including supraclavicular lymph nodes (SCLN) or not. Dose-volume histograms were calculated for each patient with special attention to the ipsilateral lung volume receiving 25 Gy (V25), in absolute and relative values, and mean lung dose. RESULTS: The study comprised 37 patients. After radiotherapy, significant decreases were observed in respiratory muscle strength, chest wall mobility, exercise capacity, and pulmonary function test results (p < 0.05). DLCO was unchanged. HRCT showed changes related to radiotherapy in 87% of the patients, which was more evident in the patients submitted to SCLN irradiation. V25% significantly correlated with radiation pneumonitis. CONCLUSIONS: In our sample of patients with breast cancer, thoracic radiotherapy seemed to have caused significant losses in respiratory and exercise capacity, probably due to chest wall restriction; SCLN irradiation represented an additional risk factor for the development of radiation pneumonitis.

Disease Severity Prediction by Spirometry in Adults with Visceral Leishmaniasis from Minas Gerais, Brazil.

Visceral leishmaniasis (VL) is associated with interstitial pneumonitis according to histology and radiology reports. However, studies to address the functional impact on respiratory function in patients are lacking. We assessed pulmonary function using noninvasive spirometry in a cross-sectional study of hospitalized adult VL patients from Minas Gerais, Brazil, without unrelated lung conditions or acute infections. Lung conditions were graded as normal, restrictive, obstructive, or mixed patterns, according to Brazilian consensus standards for spirometry. To control for regional patterns of lung function, we compared spirometry of patients with regional paired controls. Spirometry detected abnormal lung function in most VL patients (70%, 14/20), usually showing a restrictive pattern, in contrast to regional controls and the standards for normal tests. Alterations in spirometry measurements correlated with hypoalbuminemia, the only laboratory value indicative of severity of parasitic disease. Abnormalities did not correlate with unrelated factors such as smoking or occupation. Clinical data including pulmonary symptoms and duration of therapy were also unrelated to abnormal spirometry findings. We conclude that the severity of VL is correlated with a restrictive pattern of lung function according to spirometry, suggesting that there may be interstitial lung involvement in VL. Further studies should address whether spirometry could serve as an index of disease severity in the management of VL.

Exercise performance and differences in physiological response to pulmonary rehabilitation in severe chronic obstructive pulmonary disease with hyperinflation.

OBJECTIVE: Pulmonary rehabilitation (PR) improves exercise capacity in most but not all COPD patients. The factors associated with treatment success and the role of chest wall mechanics remain unclear. We investigated the impact of PR on exercise performance in COPD with severe hyperinflation. METHODS: We evaluated 22 COPD patients (age, 66 ± 7 years; FEV1 = 37.1 ± 11.8% of predicted) who underwent eight weeks of aerobic exercise and strength training. Before and after PR, each patient also performed a six-minute walk test and an incremental cycle ergometer test. During the latter, we measured chest wall volumes (total and compartmental, by optoelectronic plethysmography) and determined maximal workloads. RESULTS: We observed significant differences between the pre- and post-PR means for six-minute walk distance (305 ± 78 vs. 330 ± 96 m, p < 0.001) and maximal workload (33 ± 21 vs. 39 ± 20 W; p = 0.02). At equivalent workload settings, PR led to lower oxygen consumption, carbon dioxide production (VCO2), and minute ventilation. The inspiratory (operating) rib cage volume decreased significantly after PR. There were 6 patients in whom PR did not increase the maximal workload. After PR, those patients showed no significant decrease in VCO2 during exercise, had higher end-expiratory chest wall volumes with a more rapid shallow breathing pattern, and continued to experience symptomatic leg fatigue. CONCLUSIONS: In severe COPD, PR appears to improve oxygen consumption and reduce VCO2, with a commensurate decrease in respiratory drive, changes reflected in the operating chest wall volumes. Patients with severe post-exercise hyperinflation and leg fatigue might be unable to improve their maximal performance despite completing a PR program.

Exercise performance and differences in physiological response to pulmonary rehabilitation in severe chronic obstructive pulmonary disease with hyperinflation / Desempenho ao exercício e diferenças na resposta fisiológica à reabilitação pulmonar em doença pulmonar obstrutiva crônica grave com hiperinsuflação

Objective: Pulmonary rehabilitation (PR) improves exercise capacity in most but not all COPD patients. The factors associated with treatment success and the role of chest wall mechanics remain unclear. We investigated the impact of PR on exercise performance in COPD with severe hyperinflation. Methods: We evaluated 22 COPD patients (age, 66 ± 7 years; FEV1 = 37.1 ± 11.8% of predicted) who underwent eight weeks of aerobic exercise and strength training. Before and after PR, each patient also performed a six-minute walk test and an incremental cycle ergometer test. During the latter, we measured chest wall volumes (total and compartmental, by optoelectronic plethysmography) and determined maximal workloads. Results: We observed significant differences between the pre- and post-PR means for six-minute walk distance (305 ± 78 vs. 330 ± 96 m, p < 0.001) and maximal workload (33 ± 21 vs. 39 ± 20 W; p = 0.02). At equivalent workload settings, PR led to lower oxygen consumption, carbon dioxide production (VCO2), and minute ventilation. The inspiratory (operating) rib cage volume decreased significantly after PR. There were 6 patients in whom PR did not increase the maximal workload. After PR, those patients showed no significant decrease in VCO2 during exercise, had higher end-expiratory chest wall volumes with a more rapid shallow breathing pattern, and continued to experience symptomatic leg fatigue. Conclusions: In severe COPD, PR appears to improve oxygen consumption and reduce VCO2, with a commensurate decrease in respiratory drive, changes reflected in the operating chest wall volumes. Patients with severe post-exercise hyperinflation and leg fatigue might be unable to improve their maximal performance despite completing a PR program.

Objetivo: A reabilitação pulmonar (RP) melhora a capacidade de exercício na maioria (mas não todos) dos pacientes com DPOC. Os fatores associados ao sucesso do tratamento e o papel da mecânica da parede torácica na determinação desse sucesso ainda não é claro. Investigamos o impacto da RP no desempenho ao exercício em pacientes com DPOC e hiperinsuflação grave. Métodos: Foram avaliados 22 pacientes com DPOC (idade, 66 ± 7 anos; VEF1 = 37,1 ± 11,8% do previsto) submetidos a oito semanas de exercícios aeróbicos e treino de força. Antes e depois da RP, cada paciente também realizou um teste de caminhada de seis minutos e um teste de exercício incremental em uma bicicleta ergométrica. Durante esse último, os volumes da parede torácica (total e compartimental por pletismografia optoeletrônica) e a carga de trabalho máxima foram determinados. Resultados: Diferenças significativas foram observadas entre as médias pré e pós-RP da distância percorrida no teste de caminhada de seis minutos (305 ± 78 vs. 330 ± 96 m; p < 0,001) e da carga máxima (33 ± 21 vs. 39 ± 20 W; p = 0,02). Sob parâmetros de carga de trabalho equivalente, a RP levou a valores menores de consumo de oxigênio, produção de dióxido de carbono (VCO2) e ventilação minuto. O volume inspiratório (operacional) da caixa torácica diminuiu significativamente após a RP. Em 6 pacientes, a RP não aumentou a carga máxima. Após a RP, esses pacientes não apresentaram uma diminuição significativa na VCO2 durante o exercício, tiveram maiores volumes expiratórios finais da parede torácica com padrão respiratório mais rápido e superficial e continuaram a apresentar fadiga sintomática nas pernas. Conclusões: Na DPOC grave, a RP parece melhorar o consumo de oxigênio e reduzir VCO2, com uma diminuição proporcional no drive respiratório, mudanças essas que são refletidas nos volumes operacionais da parede torácica. Pacientes com hiperinsuflação grave pós-exercício e fadiga nas pernas podem ser incapazes de melhorar seu desempenho máximo apesar de completarem um programa de RP.

Unidirectional Expiratory Valve Method to Assess Maximal Inspiratory Pressure in Individuals without Artificial Airway.

INTRODUCTION: Maximal Inspiratory Pressure (MIP) is considered an effective method to estimate strength of inspiratory muscles, but still leads to false positive diagnosis. Although MIP assessment with unidirectional expiratory valve method has been used in patients undergoing mechanical ventilation, no previous studies investigated the application of this method in subjects without artificial airway. OBJECTIVES: This study aimed to compare the MIP values assessed by standard method (MIPsta) and by unidirectional expiratory valve method (MIPuni) in subjects with spontaneous breathing without artificial airway. MIPuni reproducibility was also evaluated. METHODS: This was a crossover design study, and 31 subjects performed MIPsta and MIPuni in a random order. MIPsta measured MIP maintaining negative pressure for at least one second after forceful expiration. MIPuni evaluated MIP using a unidirectional expiratory valve attached to a face mask and was conducted by two evaluators (A and B) at two moments (Tests 1 and 2) to determine interobserver and intraobserver reproducibility of MIP values. Intraclass correlation coefficient (ICC[2,1]) was used to determine intraobserver and interobserver reproducibility. RESULTS: The mean values for MIPuni were 14.3% higher (-117.3 ± 24.8 cmH2O) than the mean values for MIPsta (-102.5 ± 23.9 cmH2O) (p<0.001). Interobserver reproducibility assessment showed very high correlation for Test 1 (ICC[2,1] = 0.91), and high correlation for Test 2 (ICC[2,1] = 0.88). The assessment of the intraobserver reproducibility showed high correlation for evaluator A (ICC[2,1] = 0.86) and evaluator B (ICC[2,1] = 0.77). CONCLUSIONS: MIPuni presented higher values when compared with MIPsta and proved to be reproducible in subjects with spontaneous breathing without artificial airway.

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 / Métodos diagnósticos para avaliação da força muscular inspiratória e expiratória

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.

O acometimento da musculatura ventilatória (inspiratória e expiratória) é um achado clínico frequente, não somente nos pacientes com doenças neuromusculares, mas também nos pacientes com doenças primárias do parênquima pulmonar ou das vias aéreas. Embora esse acometimento seja frequente, seu reconhecimento costuma ser demorado porque seus sinais e sintomas são inespecíficos e tardios. Esse reconhecimento tardio, ou mesmo a falta de reconhecimento, é acentuado porque os exames diagnósticos usados para a avaliação da musculatura respiratória não são plenamente conhecidos e disponíveis. Usando diferentes métodos, a avaliação da força muscular ventilatória é feita para a fase inspiratória e expiratória. Os métodos usados dividem-se em volitivos (que exigem compreensão e colaboração do paciente) e não volitivos. Os volitivos, como a medida da pressão inspiratória e expiratória máximas, são os mais empregados por serem facilmente disponíveis. Os não volitivos dependem da estimulação magnética do nervo frênico associada a medida da pressão inspiratória na boca, no esôfago ou transdiafragmática. Finalmente, outro método que vem se tornando frequente é a ultrassonografia diafragmática. Acreditamos que o pneumologista envolvido nos cuidados a pacientes com doenças respiratórias deve conhecer os exames usados na avaliação da musculatura ventilatória. Por isso, o objetivo do presente artigo é descrever as vantagens, desvantagens, procedimentos de mensuração e aplicabilidade clínica dos principais exames utilizados para avaliação da força muscular ventilatória.