Variabilidade da frequência cardíaca em diferentes posições corporais e durante MASR em amputado unilateral de membro inferior / Variability of heart beat frequency in different body positions and during MASR in a person with lower member unilateral amputation

A amputação leva a redução da mobilidade e atividade física afetando os sistemas musculoesquelético, respiratório e cardiovascular. Nosso objetivo foi analisar a variabilidade da frequência cardíaca (VFC) em diferentes posições corporais e durante a Manobra de Arritmia Sinusal Respiratória (MASR) em amputados unilaterais de membros inferiores (MMII) protetizados. Estudo transversal, amostra de conveniência, avaliou 07 amputados homens de origem traumática e registradas as variáveis clínicas e VFC nas posições supino, ortostase, sedestação (10 minutos) e durante a MASR (4 minutos). Em repouso os sujeitos apresentam predominância da modulação simpática que se acentua quando assume a posição de ortostase (p = <0.01) e atenuação da complexidade autonômica (p = 0,04). Os amputados não responderam de modo adequado à MASR e observou-se alteração na complexidade da VFC (0,04). Amputados unilaterais de MMII protetizados demonstraram comportamento esperado durante a mudança ativa de postura e respostas adversas à MASR

Amputation causes decrease of mobility and physical activities, affecting the muscle-skeleton, respiratory and cardiovascular systems. Variability of heart frequency (VFC) at different body positions and during Respiratory Sinus Arrhythmia (RSA) was analyzed in people with amputation of unilateral lower members with prosthesis (MMII). Current transversal study, with convenience sample, evaluated seven males with trauma-caused amputations. Clinical variations and VFC were registered with regard to supine position, orthostasis, sedestation (10 min) and during RSA (4 min). The subjects at rest showed a predominance in increasing sympathetic modulation as the orthostatic position is achieved (p = <0.01) and attenuation of autonomic complexity (p = 0.04). People with amputation failed to respond adequately to RSA and alterations were detected in VFC complex (0.04). Unilateral amputated people with prosthesis showed expected behavior during active changes in posture and adverse responses to RSA

Association between respiratory variables and exercise capacity in COPD patients / Associação entre variáveis respiratórias e capacidade de exercício em portadores de DPOC / Asociación entre variables respiratorias y capacidad de ejercicio en portadores de EPOC

Justificativa e Objetivos: A DPOC é caracterizada pela limitação progressiva do fluxo aéreo associada a uma resposta inflamatória. O objetivo do estudo foi avaliar a influência e a associação das variáveis respiratórias sobre a capacidade de exercício em portadores de DPOC. Métodos: Estudo transversal avaliou 39 portadores de DPOC para obtenção do volume expiratório forçado no primeiro segundo (VEF1) e a capacidade vital forçada (CVF). A força muscular respiratória (FMR) avaliada em seus componentes de pressão inspiratória máxima (PImax) e pressão expiratória máxima (PEmax). Capacidade de exercício avaliada pelo Teste de Caminhada de Seis Minutos (TC6m) e Incremental Shuttle Walking Test (ISWT). Resultados: O VEF1 (% 39,8±15,3) e CVF (% 60,2±17,1) se encontram reduzidos em relação ao predito classificando-os em estadiamento grau II (21%), III (51%) e IV (28%). A PImax (92,7±14,6 % predito) e PEmax (97,6±19,0 % predito) se encontram dentro dos valores previsto para os sujeitos. Evidenciada correlação moderada entre a distância percorrida no ISWT vs VEF1 (r=0,35; p=0,02) e ISWT vs CVF (r=0,42; p<0,001), TC6m vs VEF1 (r=0,38; p=0,01) e TC6m vs CVF (r=0,52; p<0,001). A FMR se correlacionou diretamente com a distância percorrida no ISWT [PImax (r=0,44; p=0,005); PEmax (r=0,57; p<0,001)] e com TC6m [PImax (r=0,43; p=0,006); PEmax (r=0,59; p<0,001)]. A PEmax e o VEF1 influenciaram 37% do desempenho no TC6m e a PEmax influenciou isoladamente 58% da distância percorrida no ISWT. Conclusão: A força muscular respiratória e os volumes pulmonares reduzidos se associaram e influenciaram diretamente na capacidade de exercício máximo e submáximo de portadores de DPOC.(AU)

Background and Objectives: Chronic Obstructive Pulmonary Disease (COPD) is characterized by progressive airflow limitation associated with an inflammatory response. The aim of the study was to evaluate the influence and the association of respiratory variables on exercise capacity in COPD patients. Methods: A cross-sectional study evaluated 39 COPD patients to obtain forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Respiratory muscle strength (RMS) was evaluated at its maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) components. Exercise capacity was assessed by Six-Minute Walk Test (6MWT) and Incremental Shuttle Walking Test (ISWT). Results: FEV1 (39.8±15.3%predicted) and FVC (60.2±17.1% predicted) were reduced, which classified them in stages II (21%), III (51%) and IV (28%). MIP (92.7±14.6% predicted) and MEP (97.6±19.0% predicted) were within the expected values. A moderate correlation was observed between the ISWT vs FEV1 (r=0.35;p=0.02) and ISWT vs FVC (r=0.42;p<0.001), 6MWT vs FEV1 (r=0.38;p=0.01) and 6MWT vs FVC (r=0.52;p<0.001). RMS showed a moderate correlation with the ISWT [MIP (r=0.44;p=0.005); MEP (r=0.57;p<0.001)] and 6MWT [MIP (r=0.43;p=0.006); MEP (r=0.59;p<0.001)]. MEP and FEV1 influenced 37% of performance at the 6MWT and MEP alone influenced 58% of distance walked at the ISWT. Conclusion: Reducing both respiratory muscle strength and lung volumes were associated with changes in exercise and they adversely affected the maximum and submaximal exercise capacity in COPD patients.(AU)

Justificación y objetivos: La EPOC se caracteriza por la limitación progresiva del flujo aéreo asociada a una respuesta inflamatoria. El objetivo del estudio fue evaluar la influencia y la asociación de las variables respiratorias sobre la capacidad de ejercicio portadores de EPOC. Métodos: Estudio transversal evaluó 39 portadores de EPOC para obtener el volumen espiratorio forzado en el primer segundo (VEF1) y la capacidad vital forzada (CVF). La fuerza muscular respiratoria (FMR) evaluada en sus componentes de presión inspiratoria máxima (PImax) y presión espiratoria máxima (PEmax). Capacidad de ejercicio evaluada por la Prueba de Caminata de seis minutos (TC6m) e Incremental Shuttle Walking Test (ISWT). Resultados: El VEF1 (% 39,8 ± 15,3) y CVF (% 60,2 ± 17,1) se encuentran reducidos en relación al predicado clasificándolos en estadificación grado II (21%), III (51%) y IV (28%). La PImax (92,7 ± 14,6% predito) y PEmax (97,6 ± 19,0% predito) se encuentran dentro de los valores previstos para los sujetos. Se observó una correlación moderada entre la distancia recorrida en el ISWT vs VEF1 (r = 0,35; p = 0,02) e ISWT vs CVF (r = 0,42; p <0,001), TC6m vs VEF1 (r = 0,38; p = 0,01) y TC6m vs CVF (r = 0,52; p <0,001). La FMR se correlacionó directamente con la distancia recorrida en el ISWT [PImax (r = 0,44; p = 0,005); (P = 0,001) y con TC6m [PImax (r = 0,43; p = 0,006); PEmax (r = 0,59; p <0,001)]. La PEmax y el VEF1 influenciaron el 37% del rendimiento en el TC6m y la PEmax influenció aisladamente el 58% de la distancia recorrida en el ISWT. Conclusión: La fuerza muscular respiratoria y los volúmenes pulmonares reducidos se asociaron e influenciaron directamente en la capacidad de ejercicio máximo y submáximo de portadores de EPOC.(AU)

Respiratory muscle strength effect on linear and nonlinear heart rate variability parameters in COPD patients.

INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is recognized as a multisystemic inflammatory disease associated with extrapulmonary comorbidities, including respiratory muscle weakness and cardiovascular and cardiac autonomic regulation disorders. We investigated whether alterations in respiratory muscle strength (RMS) would affect cardiac autonomic modulation in COPD patients. METHODS: This study was a cross-sectional study done in ten COPD patients affected by moderate to very severe disease. The heart rate variability (HRV) signal was recorded using a Polar cardiofrequencimeter at rest in the sitting position (10 minutes) and during a respiratory sinus arrhythmia maneuver (RSA-M; 4 minutes). Linear analysis in the time and frequency domains and nonlinear analysis were performed on the recorded signals. RMS was assessed using a digital manometer, which provided the maximum inspiratory pressure (PImax) and the maximum expiratory pressure (PEmax). RESULTS: During the RSA-M, patients presented an HRV power increase in the low-frequency band (LFnu) (46.9±23.7 vs 75.8±27.2; P=0.01) and a decrease in the high-frequency band (HFnu) (52.8±23.5 vs 24.0±27.0; P=0.01) when compared to the resting condition. Significant associations were found between RMS and HRV spectral indices: PImax and LFnu (r=-0.74; P=0.01); PImax and HFnu (r=0.74; P=0.01); PEmax and LFnu (r=-0.66; P=0.01); PEmax and HFnu (r=0.66; P=0.03); between PEmax and sample entropy (r=0.83; P<0.01) and between PEmax and approximate entropy (r=0.74; P=0.01). Using a linear regression model, we found that PImax explained 44% of LFnu behavior during the RSA-M. CONCLUSION: COPD patients with impaired RMS presented altered cardiac autonomic control, characterized by marked sympathetic modulation and a reduced parasympathetic response; reduced HRV complexity was observed during the RSA-M.