High-Intensity Respiratory Muscle Training Improves Strength and Dyspnea Poststroke: A Double-Blind Randomized Trial.

OBJECTIVE: To examine whether high-intensity home-based respiratory muscle training, that is, with higher loads, delivered more frequently and for longer duration, than previously applied, would increase the strength and endurance of the respiratory muscles, reduce dyspnea and respiratory complications, and improve walking capacity post-stroke. DESIGN: Randomized trial with concealed allocation, blinded participants and assessors, and intention-to-treat analysis. SETTING: Community-dwelling patients. PARTICIPANTS: Patients with stroke, who had respiratory muscle weakness (N=38). INTERVENTIONS: The experimental group received 40-minute high-intensity home-based respiratory muscle training, 7 days per week, for 8 weeks, progressed weekly. The control group received a sham intervention of similar dose. MAIN OUTCOME MEASURES: Primary outcome was inspiratory muscle strength (via maximal inspiratory pressure), whereas secondary outcomes were expiratory muscle strength (maximal expiratory pressure), inspiratory muscle endurance, dyspnea (Medical Research Council score), respiratory complications (hospitalizations), and walking capacity (6-minute walk test). Outcomes were measured at baseline, after intervention, and 1 month beyond intervention. RESULTS: Compared to the control, the experimental group increased inspiratory (27cmH2O; 95% confidence interval [95% CI], 15 to 40) and expiratory (42cmH2O; 95% CI, 25 to 59) strength, inspiratory endurance (33 breaths; 95% CI, 20 to 47), and reduced dyspnea (-1.3 out of 5.0; 95% CI, -2.1 to -0.6), and the benefits were maintained at 1 month beyond training. There was no significant between-group difference for walking capacity or respiratory complications. CONCLUSION: High-intensity home-based respiratory muscle training was effective in increasing strength and endurance of the respiratory muscles and reducing dyspnea for people with respiratory muscle weakness post-stroke, and the magnitude of the effect was higher, than that previously reported in studies, which applied standard protocols.

Is optoelectronic plethysmography a valid instrument to measure inspiratory capacity? / A pletismografia optoeletrônica é um instrumento válido para medir a capacidade inspiratória? / ¿Tiene validez para medir la capacidad inspiratoria la pletismografía optoelectrónica?

The aim of this study was to evaluate the concurrent validity of the optoelectronic plethysmography (OEP) to measure inspiratory capacity (IC) at rest and during submaximal exercise in healthy subjects. Twelve subjects (6 Male/6 Female; 23.8±1.34 yrs) with normal body mass index and lung function completed the study protocol. Participants were assessed at rest and during a 12-minute submaximal exercise protocol on a cycle ergometer. IC maneuvers were simultaneously recorded by OEP system and by a spirometer at rest and during exercise. The percentage of discrepancy between measurements, linear regression analysis and Bland-Altman method were used for data analysis. The study was approved by the institution ethics committee. It was considered 150 valid IC maneuvers for analysis (44 for resting and 106 for exercise). The percentage of discrepancy between the measurements were -9.6 (8.6%) at rest and -4.6 (5.5%) during exercise. Regression analysis showed good linear associations between methods at rest (r2=0.90; p=0.0002) and during exercise (r2=0.96; p=0.0008). Bland-Altman analysis using data obtained during exercise showed a bias between the two methods of 0.13L. The limits of agreement indicate that the difference between methods can vary from -0.04L to 0.57L. Additionally, data was equally distributed between the upper and lower limits, demonstrating no systematic overestimation or underestimation of the IC by any of the instruments. In conclusion, this study demonstrated that the OEP is a valid evaluation system to measure IC of healthy individuals at rest and during submaximal exercise.

O objetivo deste estudo foi avaliar a validade concorrente da pletismografia optoeletrônica (POE) para medir a capacidade inspiratória (CI) de indivíduos saudáveis no repouso e durante exercício submáximo. Doze voluntários (6 H/6 M; 23,8±1,34 anos) com índice de massa corporal e prova de função pulmonar normais completaram o protocolo do estudo. Eles foram avaliados no repouso (7 minutos) e durante 12 minutos de exercício submáximo em cicloergômetro. A CI foi mensurada simultaneamente pela POE e por um espirômetro. A porcentagem de discrepância entre as medidas, a análise de regressão linear e o método de Bland-Altman foram utilizados para análise. O estudo foi aprovado pelo comitê de ética em pesquisa da instituição. Foram consideradas 150 manobras de CI válidas para análise (44 para o repouso e 106 para o exercício). A porcentagem de discrepância entre as medidas foi de -9,6 (8,6%) no repouso e -4,6 (5,5%) durante o exercício. A análise de regressão linear mostrou associações entre os dois métodos no repouso (r2=0,90; p=0,0002) e durante o exercício (r2=0,96; p=0,0008). A análise de Bland-Altman realizada com os dados do exercício mostrou viés entre os métodos de 0,13L. Os limites de concordância mostraram que a diferença entre os métodos pode variar de -0,04 L to 0,57 L. Adicionalmente, os dados distribuíram-se igualmente entre os limites de concordância, sem superestimação ou subestimação sistemática da CI. Em conclusão, o estudo demonstrou que a POE é um sistema válido para mensuração da CI de indivíduos saudáveis no repouso e durante o exercício submáximo.

Este estudio tiene como propósito evaluar la validez de la pletismografía optoelectrónica (OEP) para medir la capacidad inspiratoria (CI) en sujetos saludables tanto en reposo como durante ejercicio submáximo. Participaron de este estudio 12 sujetos (6 hombres y 6 mujeres; 23,8 ± 1,34 años de edad) con índice de masa corporal y función pulmonar normales. Los participantes fueron evaluados en reposo por 7 minutos y durante 12 minutos de ejercicio submáximo en bicicleta estática. Se grabaron simultáneamente por la OEP y por un espirómetro las maniobras de la CI tanto en reposo como durante el ejercicio. Se utilizaron el porcentaje de discrepancia en las mediciones, el análisis de regresión lineal y el método Bland-Altman para análisis de datos del estudio, el que fue aprobado por el comité de ética de la institución. Se consideró 150 maniobras CI para el análisis, las cuales 44 fueron para reposo y 106 para ejercicio. El porcentaje de discrepancia entre las medidas fue del -9,6 (un 8,6%) en reposo y del -4,6 (un 5,5%) durante el ejercicio. El análisis de regresión lineal mostró asociaciones para los métodos en reposo (r2=0,90; p=0,0002) y durante el ejercicio (r2 = 0,96; p = 0,0008). Los datos obtenidos durante el ejercicio utilizándose el análisis Bland-Altman mostraron un sesgo de 0.13L entre los métodos. Los límites de concordancia indicaron que la diferencia entre los métodos puede tener variación desde -0.04L hasta 0.57L. Además, se distribuyeron por igual los datos entre los límites de concordancia, los cuales no mostraron sobreestimación o subestimación sistemática de la CI. En conclusión, este estudio mostró que el OEP es un sistema de evaluación valido para medir la CI de sujetos saludables tanto en reposo como durante ejercicio submáximo.