Comparison of different levels of positive expiratory pressure on chest wall volumes in healthy children and patients with fibrosis / Comparação de diferentes níveis de pressão expiratória positiva em volumes de parede torácica em crianças saudáveis e pacientes com fibrose / Comparación de los diferentes niveles de la presión espiratoria positiva en los volúmenes de la pared torácica en niños saludables y pacientes con fibrosis

ABSTRACT Positive Expiratory Pressure (PEP) improves lung function, however, PEP-induced changes are not fully established. The aim of this study was to assess the acute effects of different PEP levels on chest wall volumes and the breathing pattern in children with Cystic Fibrosis (CF). Anthropometric data, lung function values, and respiratory muscle strength were collected. Chest wall volumes were assessed by Optoelectronic plethysmography at rest and during the use of different PEP levels (10 and 20 cm H2O), randomly chosen. Eight subjects with CF (5M, 11.5±3.2 years, 32±9.5 kilograms) and seven control subjects (4M, 10.7±1.5 years, 38.2±7.8 kilograms) were recruited. The CF group showed significantly lower FEF values 25-75% (CF: 1.8±0.8 vs. CG: 2.3±0.6) and FEV1/FVC ratio (CF: 0.8±0.1 vs. CG: 1±0.1) compared with the control group (p<0.05). Different PEP levels increased the usual volume in chest wall and its compartments in both groups; however, this volume was significantly higher in the control group compared with the CF group during PEP20 (CW: 0.77±0.25 L vs. 0.44±0.16 L; RCp: 0.3±0.13 L vs. 0.18±0.1 L; RCa: 0.21±0.1 L vs. 0.12±0.1 L; AB: 0.25±0.1 L vs. 0.15±0.1 L; p<0.05 for all variables). Minute ventilation was significantly higher during PEP compared with breathing at rest in both groups (p<0.005). End-expiratory volume was also higher during PEP compared with breathing at rest for chest wall and pulmonary rib cage in both groups (p<0.05). Different PEP levels may increase chest wall volumes in CF patients.

RESUMO Pressão Expiratória Positiva (PEwP) melhora a função pulmonar, entretanto, as mudanças induzidas pela PEP não estão totalmente estabelecidas. O objetivo do estudo foi avaliar os efeitos agudos de diferentes intensidades de PEP nos volumes da parede torácica (PT) e padrão respiratório em crianças com Fibrose Cística (FC). Dados antropométricos, função pulmonar e força da musculatura respiratória. Os volumes da PT foram avaliados através da Pletismografia Optoeletrônica (POE) em repouso e durante o uso de diferentes intensidades de PEP (10 e 20 cm H2O). Foram recrutados 8 sujeitos com FC (5H; 11,5 ± 3,2 anos; 32 ± 9,5 kg) e 7 sujeitos (4H; 10,7 ± 1,5 anos; 38,2 ± 7,8 kg). Grupo FC mostrou valores significativamente menores para FEF 25-75% (FC: 1,8 ± 0,8 vs. GC: 2,3 ± 0,6) e relação VEF1/CVF (FC: 0,8 ± 0,1 vs. GC: 1 ± 0,1) comparado ao grupo controle (p>0,05). Diferentes intensidades de PEP levaram a um aumento do volume corrente da PT e seus compartimentos em ambos os grupos, entretanto, este volume aumentou de forma significativa no grupo controle quando comparado ao grupo FC durante PEP20 (CW: 0,77 ± 0,25 L vs. 0,44 ± 0,16 L; RCp: 0,3 ± 0,13 L vs. 0,18 ± 0,1 L; RCa: 0,21 ± 0,1 L vs. 0,12 ± 0,1 L; AB: 0,25 ± 0,1 L vs. 0,15 ± 0,1 L; p>0,05 para todas as variáveis). A ventilação minuto aumentou de forma significativa durante a PEP em comparação a respiração em repouso para ambos os grupos (p>0,005). Volume expiratório final também foi maior durante a PEP em comparação a respiração em repouso para PT e caixa torácica pulmonar em ambos os grupos (p>0,05). Diferentes intensidades de PEP podem induzir aumentos nos volumes da parede torácica em pacientes com FC.

RESUMEN La Presión Espiratoria Positiva (PEP) mejora la función pulmonar, mientras tanto, los cambios inducidos por la PEP no están totalmente establecidos. El objetivo del estudio fue evaluar los efectos agudos de distintas intensidades de PEP en los volúmenes de la pared torácica (PT) y patrón respiratorio en niños con Fibrosis Cística (FC). Datos antropométricos, función pulmonar y fuerza de la musculatura respiratoria. Los volúmenes de la PT fueron evaluados a través de la Pletismografía Optoelectrónica (POE) en reposo y durante el uso de distintas intensidades de PEP (10 y 20 cm H2O). Fueron reclutados 8 sujetos con FC (5H; 11,5 ± 3,2 años; 32 ± 9,5 kg) y 7 sujetos (4H; 10,7 ± 1,5 años; 38,2 ± 7,8 kg). Grupo FC mostró valores significativamente menores para FEF 25-75% (FC: 1,8 ± 0,8 vs. GC: 2,3 ± 0,6) y relación VEF1/CVF (FC: 0,8 ± 0,1 vs. GC: 1 ± 0,1) comparado al grupo control (p>0,05). Distintas intensidades de PEP conllevaron a un incremento del volumen corriente de la PT y sus compartimentos en ambos los grupos, mientras tanto, este volumen incrementó de manera significativa en el grupo control cuando comparado al grupo FC durante PEP20 (CW: 0,77 ± 0,25 L vs. 0,44 ± 0,16 L; RCp: 0,3 ± 0,13 L vs. 0,18 ± 0,1 L; RCa: 0,21 ± 0,1 L vs. 0,12 ± 0,1 L; AB: 0,25 ± 0,1 L vs. 0,15 ± 0,1 L; p>0,05 para todas las variables). La ventilación minuto incrementó de manera significativa durante la PEP en comparación a la respiración en reposo para ambos grupos (p>0,005). El volumen espiratorio final también fue más grande durante la PEP en comparación a la respiración en reposo para PT y la caja torácica pulmonar en ambos los grupos (p>0,05). Las distintas intensidades de PEP pueden inducir incrementos en los volúmenes de la pared torácica en pacientes con FC.

Effects of positive expiratory pressure on pulmonary clearance of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid in healthy individuals / Efeitos da pressão expiratória positiva na depuração pulmonar do ácido dietilenotriaminopentacético marcado com tecnécio-99m em aerossol em indivíduos saudáveis

ABSTRACT Objective: To evaluate the effects of positive expiratory pressure (PEP) on pulmonary epithelial membrane permeability in healthy subjects. Methods: We evaluated a cohort of 30 healthy subjects (15 males and 15 females) with a mean age of 28.3 ± 5.4 years, a mean FEV1/FVC ratio of 0.89 ± 0.14, and a mean FEV1 of 98.5 ± 13.1% of predicted. Subjects underwent technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scintigraphy in two stages: during spontaneous breathing; and while breathing through a PEP mask at one of three PEP levels-10 cmH2O (n = 10), 15 cmH2O (n = 10), and 20 cmH2O (n = 10). The 99mTc-DTPA was nebulized for 3 min, and its clearance was recorded by scintigraphy over a 30-min period during spontaneous breathing and over a 30-min period during breathing through a PEP mask. Results: The pulmonary clearance of 99mTc-DTPA was significantly shorter when PEP was applied-at 10 cmH2O (p = 0.044), 15 cmH2O (p = 0.044), and 20 cmH2O (p = 0.004)-in comparison with that observed during spontaneous breathing. Conclusions: Our findings indicate that PEP, at the levels tested, is able to induce an increase in pulmonary epithelial membrane permeability and lung volume in healthy subjects.

RESUMO Objetivo: Avaliar os efeitos da pressão expiratória positiva (PEP) na permeabilidade da membrana epitelial pulmonar em indivíduos saudáveis. Métodos: Foi avaliada uma coorte de 30 indivíduos saudáveis (15 homens e 15 mulheres), com média de idade de 28,3 ± 5,4 anos, média da relação VEF1/CVF de 0,89 ± 0,14 e média de VEF1 de 98,5 ± 13,1% do previsto. Os indivíduos foram submetidos a cintilografia pulmonar por inalação de radioaerossol de ácido dietilenotriaminopentacético marcado com tecnécio-99m (99mTc-DTPA em inglês) em dois estágios: durante respiração espontânea e durante respiração com uma máscara de PEP de 10 cmH2O (n = 10), 15 cmH2O (n = 10) ou 20 cmH2O (n = 10). O 99mTc-DTPA foi nebulizado por 3 min, e sua depuração foi registrada por cintilografia por um período de 30 min durante respiração espontânea e por um período de 30 min durante a respiração com uma máscara de PEP. Resultados: A depuração pulmonar do 99mTc-DTPA foi significativamente menor quando PEP foi aplicada a 10 cmH2O (p = 0,044), 15 cmH2O (p = 0,044) e 20 cmH2O (p = 0,004), em comparação com a observada durante a respiração espontânea. Conclusões: Nossos achados indicam que o uso de PEP nos níveis testados pode induzir um aumento na permeabilidade da membrana epitelial pulmonar e no volume pulmonar em indivíduos saudáveis.

Acute effects of Expiratory Positive Airway Pressure (EPAP) on different levels in ventilation and electrical activity of sternocleidomastoid and parasternal muscles in Chronic Obstructive Pulmonary Disease (COPD) patients: a randomized controlled trial

ABSTRACT Objective To investigate the acute effects of EPAP on the activity of sternocleidomastoid (SCM), parasternal muscles and ventilatory parameters in COPD patients. Method Twenty-four patients with COPD were studied using surface electromyography (sEMG) and a ventilometer. Patients were randomly assigned to EPAP 10 cmH2O-EPAP10 or 15 cmH2O-EPAP15 for 20 minutes. Results The parasternal muscle sEMG activity increased during EPAP10 and EPAP15; however, a greater and significant increase was observed with EPAP10 (mean between-group difference: 12.5% RMS, 95% CI: 9.5 to 15.4, p<0.001). In relation to the baseline, at 10 and 20 minutes and upon recovery, respectively parasternal activity increased by 23.9%, 28.9% and 19.1% during EPAP10 and by 10.7% at 10 and 20 minutes and upon recovery, respectively, 11.4% and 6.9% during EPAP15 at 10 and 20 minutes and upon recovery, respectively. The sEMG activity of SCM muscle showed an opposite pattern, increasing with EPAP15 and decreasing with EPAP10 (mean between-group difference: 15.5% RMS, 95% CI: 12.6 to 18.4, p<0.001). SCM muscle activity during EPAP15, increased by 4.8% and 6.1% at 10 and 20 minutes and decreased by -4.0% upon recovery compared to decreases of –5.6%, –20.6% and –21.3% during EPAP10 at 10, 20 minutes, and recovery. Ventilation at both EPAP intensities promoted significant reductions in respiratory rate (RR) and dyspnea, more pronounced in EPAP15: RR (mean between-group difference: –3,8bpm, 95%CI: –7,5 to –0,2, p=0,015) and dyspnea (mean between-group difference: –1.01, 95%CI: –1.4 to –0.53, p=0.028) . Conclusion In COPD patients, the use of EPAP10 was more effective in reducing accessory inspiratory activity and increasing parasternal activity, which was accompanied by an improvement in ventilation and a reduction in dyspnea.

Effects of non-invasive ventilation and posture on chest wall volumes and motion in patients with amyotrophic lateral sclerosis: a case series

ABSTRACT Background The effects of non-invasive ventilation (NIV) on the breathing pattern and thoracoabdominal motion of patients with amyotrophic lateral sclerosis (ALS) are unknown. Objectives 1) To analyze the influence of NIV on chest wall volumes and motion assessed by optoelectronic plethysmography in ALS patients and 2) to compare these parameters in the supine and sitting positions to those of healthy individuals (without NIV). Method Nine ALS patients were evaluated in the supine position using NIV. In addition, the ALS patients and nine healthy individuals were evaluated in both sitting and supine positions. Statistical analysis was performed using the paired Student t-test or Wilcoxon test and the Student t-test for independent samples or Mann-Whitney U test. Results Chest wall volume increased significantly with NIV, mean volume=0.43 (SD=0.16)L versus 0.57 (SD=0.19)L (p=0.04). No significant changes were observed for the pulmonary rib cage, abdominal rib cage, or abdominal contribution. The index of the shortening velocity of the diaphragmatic muscle, mean=0.15 (SD=0.05)L/s versus 0.21 (SD=0.05)L/s (p<0.01), and abdominal muscles, mean=0.09 (SD=0.02)L/s versus 0.14 (SD=0.06)L/s (p<0.01), increased during NIV. Comparisons between the supine and sitting positions showed similar changes in chest wall motion in both groups. However, the ALS patients presented a significantly lower contribution of the abdomen in the supine position compared with the controls, mean=56 (SD=13) versus 69 (SD=10) (p=0.02). Conclusions NIV improved chest wall volumes without changing the contribution of the chest wall compartment in ALS patients. In the supine position, ALS patients had a lower contribution of the abdomen, which may indicate early diaphragmatic dysfunction.

Effects of diaphragmatic control on the assessment of sniff nasal inspiratory pressure and maximum relaxation rate

OBJECTIVE: To assess the influence of diaphragmatic activation control (diaphC) on Sniff Nasal-Inspiratory Pressure (SNIP) and Maximum Relaxation Rate of inspiratory muscles (MRR) in healthy subjects. METHOD: Twenty subjects (9 male; age: 23 (SD=2.9) years; BMI: 23.8 (SD=3) kg/m2; FEV1/FVC: 0.9 (SD=0.1)] performed 5 sniff maneuvers in two different moments: with or without instruction on diaphC. Before the first maneuver, a brief explanation was given to the subjects on how to perform the sniff test. For sniff test with diaphC, subjects were instructed to perform intense diaphragm activation. The best SNIP and MRR values were used for analysis. MRR was calculated as the ratio of first derivative of pressure over time (dP/dtmax) and were normalized by dividing it by peak pressure (SNIP) from the same maneuver. RESULTS: SNIP values were significantly different in maneuvers with and without diaphC [without diaphC: -100 (SD=27.1) cmH2O/ with diaphC: -72.8 (SD=22.3) cmH2O; p<0.0001], normalized MRR values were not statistically different [without diaphC: -9.7 (SD=2.6); with diaphC: -8.9 (SD=1.5); p=0.19]. Without diaphC, 40% of the sample did not reach the appropriate sniff criteria found in the literature. CONCLUSION: Diaphragmatic control performed during SNIP test influences obtained inspiratory pressure, being lower when diaphC is performed. However, there was no influence on normalized MRR.

Increase in perceived stress is correlated to lower heart rate variability in healthy young subjects / Aumento no estresse percebido correlaciona-se com diminuição da variabilidade da frequência cardíaca em indivíduos jovens saudáveis

Emotional stress is a risk factor for cardiovascular disease. Decreased heart rate variability (HRV) is associated to increased mortality rates in certain heart diseases. Current study assessed the co-relation between perceived stress and HRV parameters. The correlation between psychological stress, measured by the perceived stress scale (PSS-14), and HRV parameters obtained during 5 min. at rest was evaluated. Data from 35 healthy young volunteers demonstrated a significant correlation between PSS-14 scores and Low Frequency-LF (ms2) by frequency domain HRV analysis. Other variables such as High Frequency and Standard Deviation of R-R intervals had also negative coefficients but did not have any significant correlation with PSS-14. No correlation between PSS-14 and sympathovagal balance parameters was found. Data interpretation demonstrated that increase in perceived stress was correlated to decrease in heart rate variability, which may point out an important mechanism in cardiovascular pathophysiology that should be further investigated.

O estresse emocional é um fator de risco para doença cardiovascular. A diminuição da Variabilidade da Frequência Cardíaca (VFC) está associada ao aumento da mortalidade em algumas doenças cardíacas. Este estudo teve como objetivo avaliar a correlação entre o estresse percebido e os parâmetros da VFC. Dessa maneira, avaliou-se a correlação existente entre o estresse psicológico mensurado através da escala de estresse percebido (PSS -14) e parâmetros de VFC obtidos durante 5 min. ao repouso. Dados de 35 voluntários jovens e saudáveis demonstraram uma correlação significativa do PSS-14 com os valores de baixa freqüência- LF (ms²) na análise da VFC no domínio frequência. Outras variáveis, tais como alta freqüência e desvio padrão dos intervalos RR, também tiveram coeficientes negativos, mas não se correlacionaram com a PSS-14. Nenhuma correlação entre o PSS-14 e os parâmetros do balanço simpato-vagal foi encontrada. Portanto, a interpretação dos dados demonstra que o aumento no estresse percebido se correlacionou com a diminuição da variabilidade da frequência cardíaca, o que pode ser indicativo de um mecanismo importante na fisiopatologia cardiovascular que deve ser melhor investigado.

Identification of peripheral arterial disease in diabetic patients and its association with quality of life, physical activity and body composition / Identificação de doença arterial obstrutiva periférica e sua associação com a qualidade de vida, a atividade física e a composição corporal em pacientes diabéticos

Diabetes mellitus (DM) is a risk factor for peripheral arterial disease (PAD). Neither the prevalence of PAD in type 2 (T2) DM nor its detrimental effects on quality of life (QoL) or physical activity (PA) have been well described in the Brazilian population. OBJECTIVES: To evaluate the prevalence of newly diagnosed PAD and its associations with QoL, PA and body composition in a sample of T2DM patients from a University Hospital. METHODS: Seventy-three (73) T2DM patients without previous diagnoses of major complications related to T2DM were enrolled. PAD was assessed using the ankle-brachial index (ABI); QoL was measured using a translated and validated SF-36 questionnaire; PA was measured using a modified Baecke questionnaire; and body composition was measured by segmental multi-frequency bioelectrical impedance. RESULTS: PAD prevalence was 13.7%, predominantly of mild severity (ABI between 0.8-0.9). The ABI results correlated with age (ρ=-0.26, P=0.03), DM duration (ρ=-0.28, P=0.02) and systolic and diastolic blood pressure (ρ=-0.33, P=0.007 and ρ=-0.28, P=0.02; respectively). Scores for the SF-36 physical component summary (PCS) were below the normal range, but no negative impact from PAD was identified by the PCS scores (normal-ABI 42.9±11.2 vs. PAD-ABI 38.12±11.07) or the Baecke PA results. Body composition analysis detected excessive body fat, especially in women, but there was no difference between groups. CONCLUSIONS: The prevalence of previously undiagnosed PAD in this population of T2DM patients was 13.7%, predominantly mild and asymptomatic forms, and was not yet associated with worsened QoL, PA levels or body composition variables...

O Diabetes Mellitus (DM) é fator de risco para a doença arterial obstrutiva periférica (DAOP). A prevalência de DAOP no DM tipo 2 (T2) e o prejuízo adicional causado por esta na qualidade de vida (QoL) e na atividade física (AF) não são bem descritos na população brasileira. OBJETIVOS: Avaliar a prevalência e a associação da DAOP recém-diagnosticada com a QoL, a AF e a composição corporal em pacientes T2DM provenientes de um hospital universitário. MÉTODOS: Setenta e três pacientes T2DM, sem complicações maiores relacionadas ao T2DM, foram incluídos. A DAOP foi avaliada pelo índice tornozelo-braquial (ITB); a QoL, pelo questionário traduzido e validado SF-36, e a AF, pelo questionário modificado de Baecke. A composição corporal foi avaliada pela impedância bioelétrica segmentar multifrequencial. RESULTADOS: A prevalência de DAOP foi 13,7%, predominantemente de severidade leve (ITB entre 0,8-0,9). O ITB correlacionou-se com a idade (ρ= -0,26; P= 0,03), a duração do DM (ρ=-0,28; P=0,02) e a pressão arterial sistólica e diastólica (ρ= -0,33; P= 0,007 e ρ= -0,28; P= 0,02; respectivamente). O sumário de saúde física (PCS) do questionário SF-36 estava abaixo da variação normal; contudo, nenhum impacto negativo da DAOP foi identificado no PCS (ABI normal = 42,9±11,2 vs. ABI-DAOP = 38,12±11,07) ou no nível de AF. A análise da composição corporal demonstrou gordura corporal excessiva, especialmente em mulheres; contudo, sem diferenças entre grupos. CONCLUSÃO: A prevalência de DAOP sem diagnóstico prévio nesta amostra de pacientes T2DM foi de 13,7%, predominantemente assintomática e leve, e ainda não associada com piores índices de QoL, nível de AF e composição corporal...

Costs and benefits of Pulmonary Rehabilitation in Chronic Obstructive Pulmonary Disease: a randomized controlled trial

Objective: The current study evaluated the costs and benefits of a simple aerobic walking program for patients with chronic obstructive pulmonary disease (COPD). Method: This was a blinded randomized controlled clinical trial that recruited 72 patients diagnosed with COPD, 40 of whom were included in the study and divided into two groups [control group (CG) and pulmonary rehabilitation group (GPR)]. We assessed pulmonary function, distance covered during the 6-minute walk test (6MWT), respiratory and peripheral muscle strength, health-related quality of life (HRQOL), body composition, and level of activities of daily living (ADLs) before and after an 8-week walking program. The financial costs were calculated according to the pricing table of the Brazilian Unified Health System (SUS). Results: Only 34 of the 40 patients remained in the final sample; 16 in the CG and 18 in the GPR (FEV1: 50.9±14% predicted and FEV1: 56±0.5% predicted, respectively). The intervention group exhibited improvements in the 6MWT, sensation of dyspnea and fatigue, work performed, BODE index (p<0.01), HRQOL, ADL level (p<0.001), and lower limb strength (p<0.05). The final mean cost per patient for the GPR was R$ 148.75 (~US$ 75.00) and no patient significantly exceeded this value. However, 2 patients in the CG did exceed this value, incurring a cost of R$ 689.15 (~US$ 345.00). Conclusion: Aerobic walking demonstrated significant clinical benefits in a cost-efficient manner in patients with COPD. .

Heart Rate Variability at rest and after the 6-minute walk test (6MWT) in children with cystic fibrosis

BACKGROUND: Cystic fibrosis (CF) is a multisystem disease that affects the cardiorespiratory system and the cardiac autonomic control may be altered at rest and after a submaximal exercise. OBJECTIVE: To assess the cardiac autonomic control by heart rate variability (HRV) analysis before and after a 6-minute walk test (6MWT). METHOD: Thirteen children diagnosed with Cystic Fibrosis (CFG) aged 12±2.7 years (FEV1/FVC: 0.83±0.11, FEV1: 71.4±21 %pred) and 12 healthy children (control group-CG) aged 11.4±2.4 years (FEV1/FVC: 0.91±0.12, FEV1: 91.6±17.4 %pred) were included in the study. HRV was evaluated prior to and immediately after the 6MWT and the heart rate recovery assessed on the first and second minute after test. RESULTS: Prior to exercise, CF patients presented higher values for the variables LFnu (53.2±15.0 vs. 32.8±7.9, p=0.0003) and LF/HF (1.25±0.72 vs. 0.49±0.18, p<0.006) as well as lower values of HF% (25.4±18.4 vs. 53±9.6, p=0.002) and HFnu (47.3±14.7 vs. 68.3±8.7, p0.001) when compared to CG. After the 6MWT, both groups demonstrated HRV recovery to baseline levels; however, the differences between CFG and CG were maintained for the variables LF(ms 2) (846.7±754.8 vs. 345.6±197.2, p=0.02); LF% (35.4±8.1 vs. 25.9±6.2, p=0.002); LFnu (60.0±16.3 vs. 34.9±8.7, p<0.0001); HF% (27.4±13.7 vs. 48.1±6.3, p=0.0003); HFnu (40.4±15.8 vs. 65.6±8.2, p=0.0003) and LF/HF (1.9±1.7 vs. 0.5±0.2, p=0.0001). CONCLUSIONS: Children with cystic fibrosis exhibited predominance of sympathetic activity at rest that persisted after the 6-minute walking test when compared to the control group. .

Acute effects of different inspiratory resistive loading on heart rate variability in healthy elderly patients

BACKGROUND: The cardiovascular system is noticeably affected by respiration. However, whether different inspiratory resistive loading intensities can influence autonomic heart rate (HR) modulation remains unclear. OBJECTIVE: The objective was to investigate HR modulation at three different inspiratory resistive loading intensities in healthy elderly men. METHOD: This was a prospective, randomized, double-blind study that evaluated 25 healthy elderly men. Cardiac autonomic modulation was assessed using heart rate variability (HRV) indices. All of the volunteers underwent maximal inspiratory pressure (MIP) measurements according to standardized pulmonary function measurements. Three randomly-applied inspiratory resistive loading (30, 60 and 80% of MIP) intensities were then applied using an inspiratory resistance device (POWERbreathe, Southam, UK), during which the volunteers were asked to inhale for 2 seconds and exhale for 3 seconds and complete 12 breaths per minute. Each effort level was performed for 4 minutes, and HR and the distance between 2 subsequent R waves of electrocardiogram (R-R intervals) were collected at rest and at each intensity for further HRV analysis. RESULTS : The parasympathetic HRV (rMSSD, SD1 and HF) indices demonstrated lower values at 80% (rMSSD: 19±2 ms, SD1: 13±2 ms and HF: 228±61 ms2) than at 30% MIP (rMSSD: 25±3 ms, SD1: 18±2 ms and HF: 447±95 ms2; p<0.05). CONCLUSIONS: Lower inspiratory resistive loading intensities promoted a marked and positive improvement of parasympathetic sinus node modulation. .

Monitoring respiratory muscle strength assists in early diagnosis of respiratory dysfunction as opposed to the isolated use of pulmonary function evaluation in amyotrophic lateral sclerosis / Monitoramento da força muscular respiratória em detrimento do uso isolado da avaliação da função pulmonar para o diagnóstico precoce de disfunção respiratória em pacientes com esclerose lateral amiotrófica

It was study the relationship between respiratory muscle strength and forced vital capacity (FVC) in patients with amyotrophic lateral sclerosis (ALS) versus healthy subjects. Pulmonary function and respiratory muscle strength [maximal inspiratory (PImax), maximal expiratory (PEmax) and sniff nasal inspiratory pressure (SNIP)] were assessed in patients with ALS and healthy subjects, matched using cutoffs established in the literature for impaired pulmonary function and respiratory muscle weakness. Twenty-eight ALS patients and 28 healthy subjects were studied. We found sensitivity and specificity for PImax, PEmax and SNIP of 75/58%, 81/67% and 75/67%. The Receiver Operating Characteristic curve (ROC curve) indicated that the variables PImax, PEmax and SNIP can identify differences in respiratory muscle strength between ALS and healthy individuals at 0.89, 0.9 and 0.82, respectively. A positive correlation was recorded between FVC (%) versus SNIP, PImax and PEmax. In ALS, monitoring respiratory muscle strength assists in early diagnosis of respiratory dysfunction as opposed to the isolated use of FVC. .

Estudar a relação entre a força dos músculos respiratórios e a capacidade vital forçada (CVF) em pacientes com esclerose lateral amiotrófica (ELA) e sujeitos saudáveis. Avaliamos a função pulmonar e a força dos músculos respiratórios [pressão inspiratória (PImax), pressão expiratória (PEmax) e pressão inspiratória nasal de sniff (SNIP)] utilizando pontos de corte estabelecidos na literatura para diagnóstico de fraqueza muscular respiratória. Foram estudados 28 pacientes com ELA e 28 sujeitos saudáveis. Encontramos sensibilidade e especificidade para PImax, PEmax e SNIP de 75/58%, 81/67% e 75/67%. A curva ROC (Receiver Operating Characteristic) indicou que as variáveis PImax, PEmax e SNIP podem identificar diferenças na força dos músculos respiratórios em pacientes com ELA versus sujeitos saudáveis em 0,89, 0,9 e 0,82 respectivamente. Foi encontrada uma correlação positiva entre CVF (%) e SNIP, PImax e PEmax. Em pacientes com ELA, o monitoramento da força muscular respiratória auxilia no diagnóstico precoce da disfunção em detrimento do uso da CVF isolada. .

Valores de referência da pressão inspiratória nasal em indivíduos saudáveis no Brasil: estudo multicêntrico / Reference values for sniff nasal inspiratory pressure in healthy subjects in Brazil: a multicenter study

OBJETIVO: Os objetivos do presente estudo foram determinar equações de referência para pressão inspiratória nasal (PIN) e propor equações de referência para a população brasileira. MÉTODOS: Foram avaliados 243 indivíduos saudáveis (111 homens e 132 mulheres), entre 20 e 80 anos, com CVF > 80% e razão VEF1/CVF > 85% do predito. Todos os indivíduos realizaram testes de força muscular respiratória para a determinação de PIN, PImáx e PEmáx. RESULTADOS: Os valores da PIN foram maiores no sexo masculino que no feminino (p < 0,05), e a PIN apresentou correlação negativa com a idade para homens (r = -0,29; p < 0,001) e mulheres (r = -0,33; p < 0,0001). A análise de regressão linear múltipla também revelou que a idade permaneceu exercendo influência na predição da PIN em homens (R² = 0,09) e mulheres (R² = 0,10). Os valores preditos da PIN encontrados foram superiores àqueles obtidos em outras populações. CONCLUSÕES: Nesse contexto, sugerem-se equações preditivas para PIN em indivíduos brasileiros saudáveis na faixa etária entre 20 e 80 anos, com o intuito de minimizar discrepâncias diagnósticas ao comparar indivíduos.

OBJECTIVE: The objectives of this study were to determine reference values for sniff nasal inspiratory pressure (SNIP) and to propose reference equations for the population of Brazil. METHODS: We evaluated 243 healthy individuals (111 males and 132 females), between 20 and 80 years of age, with an FVC and FEV1/FVC ratio > 80% and > 85% of the predicted value, respectively. All of the subjects underwent respiratory muscle strength tests to determine MIP, MEP, and SNIP. RESULTS: We found that SNIP values were higher in males than in females (p < 0.05) and that SNIP correlated negatively with age, for males (r = -0.29; p < 0.001) and for females (r = -0.33; p < 0.0001). Linear regression also revealed that age influenced the predicted SNIP, for males (R² = 0.09) and females (R² = 0.10). We obtained predicted SNIP values that were higher than those obtained for other populations. CONCLUSIONS: We have devised predictive equations for SNIP to be used in adults (20-80 years of age) in Brazil. These equations could help minimize diagnostic discrepancies among individuals.

Força muscular respiratória e perfil postural e nutricional em crianças com doenças neuromusculares / Respiratory muscle strength, nutritional and postural profile in children with neuromuscular diseases

INTRODUÇÃO: As doenças neuromusculares infantis são crônicas, degenerativas e determinam alterações funcionais, musculares e nutricionais. OBJETIVOS: Avaliar sistematicamente a força muscular respiratória e o perfil postural e nutricional de crianças com doenças neuromusculares em seguimento multidisciplinar institucional.MATERIAIS E MÉTODOS: Foram estudados pacientes com diferentes doenças neuromusculares por meio da verificação da força muscular respiratória, da avaliação nutricional de massa muscular, do índice de massa corpórea e da porcentagem (%) de gordura corporal, além de avaliação postural e dos padrões de movimento.RESULTADOS: Foram avaliados 41 sujeitos. As crianças do sexo masculino predominaram na população em estudo, sendo 82,9% dela (n = 34), e os outros 17,1% (n = 7) eram do sexo feminino. A média de idade encontrada foi de 9,65 ± 3,11 anos. O principal diagnóstico encontrado foi Distrofia Muscular de Duchenne, 43,9% (n = 18), seguido de Atrofia Muscular Espinhal, 9,75% (n = 4), Distrofia Congênita, 7,31% (n = 3), Distrofia Muscular de Cinturas, Polineuropatia e Miopatia Congênita, todos com 4,9% (n = 2), além de Distrofia Muscular Progressiva, Miastenia Grávis, Charcoot Marie Toot, Emery Dreifuss, encontrados em 2,43% (n = 1). Foi verificada uma diminuição da força muscular respiratória (PImáx = 81 ± 24,3 cmH2O, 91% predito e PEmáx = 70 ± 29,6 cmH2O, 72% predito), mais evidente nos músculos expiratórios. A Hiperlordose lombar foi encontrada em 26 pacientes (64%) e 9 pacientes (22%) já haviam perdido a capacidade de deambular. Em relação ao perfil nutricional, 90% dos pacientes (n = 30) mostraram uma alta incidência de perda de reserva muscular e 52% deles (n = 13) apresentaram a porcentagem de gordura corporal abaixo do aceitável. CONCLUSÃO: A avaliação multidisciplinar das doenças neuromusculares pediátricas podem auxiliar no estabelecimento de tratamento precoce da Fisioterapia para melhorar a qualidade de vida dos pacientes e cuidadores.

INTRODUCTION: Neuromuscular diseases that affect childrens are degenerative and chronic disorders that lead to functional, muscular and nutritional impairments. OBJECTIVE: Assess respiratory strength, postural and nutritional profile in childrens with neuromuscular disorder followed in on ambulatory outpatients clinics. MATERIALS AND METHODS: Patients with neuromuscular diseases were assessed in relation to respiratory muscle strength (PImax and PEmax), postural profile, walk capacity and nutrition assessment that includes body mass index, muscular mass and body fat percentage. RESULTS: Forty-one patients were included in the study. Male children's were predominant in the group, 82,9% (n = 34) of them, while female were 17,1% (n = 7). The mean age was 9,65 ± 3,11 years. The most common disorder was Duchenne Miotonic Dystrophy, found in 43.9% (n = 18) of the children, followed by Spinal Muscular Atrophy, 9,75% (n = 4), Congenital muscular dystrophy, 7,31% (n = 3), Erb's scapulohumeral Dystrophy, Polyneuropathy and Congenital Myopathy, all in 4,9% (n = 2), while Progressive Muscular Dystrophy, Myasthenia Gravis, Charcoot Marie Toot, Emery Dreifuss was found in 2,43% (n = 1) of them. We found a decrease in respiratory muscle strength (PImax = 81 ± 24,3 cmH2O, 91% predict and PEmax = 70 ± 29,6 cmH2O, 72% predict), more evident in expiratory muscles. Lumbar hyperlordosis were found in 26 (64%) of the patients, 9 patients (22%) lost their ability to walk. In relation to nutritional profile, 90% (n = 30) showed one high incidence of muscular reserve loss and 52% (n = 13) of the patient's body fat was bellow acceptable range. CONCLUSION: Multidisciplinary evaluation of children neuromuscular diseases may assist in establishing early Physical Therapy intervention to improve the quality of life of both patients and caregivers.

Variação diurna de parâmetros de função pulmonar e de força muscular respiratória em pacientes com DPOC / Diurnal variations in the parameters of pulmonary function and respiratory muscle strength in patients with COPD

OBJETIVO: Avaliar a magnitude de mudanças diurnas em parâmetros de função pulmonar e de força e resistência dos músculos respiratórios em uma amostra de pacientes com DPOC. MÉTODOS: Um grupo com 7 pacientes foi submetido a espirometria e a determinação de PImáx e PEmáx em dois momentos (entre 8h00 e 8h30 e entre 16h30 e 17h00) em um único dia. Os pacientes permaneceram em repouso na área do laboratório entre as avaliações. RESULTADOS: De acordo com o sistema de estadiamento da Global Initiative for Chronic Obstructive Pulmonary Disease, a doença foi classificada em moderada, grave e muito grave em 1, 3 e 3 pacientes, respectivamente. Da primeira para a segunda avaliação, houve uma queda significativa em CVF, VEF1 e PEmáx (de 13%, 15% e 10%, respectivamente), bem como uma queda não significativa em PFE, PImáx e ventilação voluntária máxima (de 9%, 3% e 11%, respectivamente). CONCLUSÕES: Nesta amostra de pacientes com DPOC, houve variações diurnas nos parâmetros de função pulmonar e de força de músculos respiratórios. Os valores de VEF1, CVF e PEmáx foram significativamente menores à tarde do que de manhã.

OBJECTIVE: To evaluate the magnitude of diurnal changes in the parameters of pulmonary function and respiratory muscle strength/endurance in a sample of patients with COPD. METHODS: A group of 7 patients underwent spirometry, together with determination of MIP and MEP, at two distinct times (between 8:00 and 8:30 a.m. and between 4:30 and 5:00 p.m.) on a single day. Between assessments, the patients remained at rest in the laboratory. RESULTS: In accordance with the Global Initiative for Chronic Obstructive Pulmonary Disease staging system, COPD was classified as moderate, severe, and very severe in 1, 3, and 3 of the patients, respectively. From the first to the second assessment, there were significant decreases in FVC, FEV1, and MEP (of 13%, 15%, and 10%, respectively), as well as (less than significant) decreases in PEF, MIP, and maximal voluntary ventilation (of 9%, 3%, and 11%, respectively). CONCLUSIONS: In this sample of COPD patients, there were diurnal variations in the parameters of pulmonary function and respiratory muscle strength. The values of FEV1, FVC, and MEP were significantly lower in the afternoon than in the morning.

Variabilidade da frequência cardíaca em pacientes com Distrofia Miotônica tipo 1 / Heart rate variability in Myotonic Dystrophy type 1 patients

FUNDAMENTO: O envolvimento cardíaco é comum em pacientes com Distrofia Miotônica (DM). A Variabilidade da Frequência Cardíaca (VFC) é uma técnica simples e confiável que pode ser útil para estudar a influência do sistema nervoso autonômico sobre o coração. OBJETIVO: Estudar a variabilidade da frequência cardíaca em pacientes com DM tipo 1. MÉTODOS: Estudamos a VFC durante registros de 5 minutos em pacientes com DM em um grupo controle saudável. Analisamos os domínios da frequência (BF e AF) em unidades normalizadas (un) e balanço simpático-vagal, na posição sentada e em decúbito dorsal. RESULTADOS: Dezessete pacientes (10 homens e 7 mulheres) e dezessete indivíduos pareados saudáveis (10 homens e 7 mulheres) foram estudados. As modulações simpática e parassimpática do coração elevadas em pacientes do sexo masculino com DM da posição em decúbito dorsal para a posição sentada em 19% da AFun e a razão BF/AF aumentaram 42,3%. Na posição sentada, os pacientes do sexo masculino com DM apresentaram balanços simpático-vagal significativamente mais elevados em 50,9% em comparação com indivíduos controles saudáveis. A VFC foi influenciada tanto pelo sexo quanto pela enfermidade apresentada. O sexo influenciou a AFun na posição em decúbito dorsal, enquanto a razão BF/AF e AFun foi afetada em ambas as posições. Análises post hoc mostraram que o sexo afeta significativamente pacientes com DM e indivíduos saudáveis de diferentes maneiras (p < 0,01). O domínio de baixa frequência na posição sentada (AFun) foi significativamente influenciado pela enfermidade. CONCLUSÃO: Os resultados deste estudo sugerem que o estímulo simpático em pacientes de meia-idade do sexo masculino com DM que não está gravemente comprometido e apresenta duração moderada da doença parece ser maior do que em indivíduos saudáveis pareados.

BACKGROUND: Cardiac involvement is common in myotonic dystrophy (MD) patients. Heart rate variability (HRV) is a simple and reliable technique that can be useful for studying the influence of the autonomic nervous system on the heart. OBJECTIVE: Study heart rate variability in patients with type 1 MD. METHODS: We studied HRV during 5-minute recordings in MD patients and in a healthy control group. We analyzed frequency domains (LF and HF) in normalized units (nu) and sympathovagal balance, in the sitting and supine position. RESULTS: Seventeen patients (10 men and 7 women) and seventeen matched healthy individuals (10 men and 7 women) were studied. Sympathetic and parasympathetic modulations of the heart increased in male MD patients from supine to sitting position in 19% of LFnu and the LF/HF ratio rose by 42.3%. In the sitting position, male MD patients exhibited significantly higher sympathovagal balances in 50.9% compared to healthy control individuals. HRV was influenced by both gender and disease. Gender influenced LFnu in the supine position while the LF/HF ratio and HFnu were affected in both positions. Post hoc analyses showed that gender significantly impacts MD patients and healthy individuals in different ways (p < 0.01). The low frequency domain in the sitting position (LFnu) was significantly influenced by the disease. CONCLUSION: The results of this study suggest that the sympathetic drive in middle-aged male MD patients who are not severely impaired and present moderate disease duration seems to be greater than in healthy matched individuals.

Comparação entre o manovacuômetro nacional e o importado para medida da pressão inspiratória nasal / Comparison between a national and a foreign manovacuometer for nasal inspiratory pressure measurement

CONTEXTUALIZAÇÃO: A medida da pressão inspiratória nasal, conhecida como sniff teste, desenvolvida como um novo teste de força muscular inspiratória, utilizada principalmente em doenças neuromusculares, é de fácil realização e não invasiva. Apesar da importância clínica da avaliação da pressão inspiratória nasal, não existe um instrumento nacional disponível para realizá-la. OBJETIVOS: Comparar os manovacuômetros eletrônicos nacional e importado para a avaliação da pressão inspiratória nasal em pessoas saudáveis. MÉTODOS: Foram avaliados 18 voluntários saudáveis (idade 21,4±2,8 anos, IMC 23,4±2,5 Kg/m² , CVF 102,1±10,3 por centopred, VEF1 98,4±1 por centopred) por meio de duas medidas de pressão inspiratória nasal em dois equipamentos diferentes: um nacional e outro importado. Todos os sujeitos realizaram a manobra no mesmo horário do dia, em dias ocasionais, sendo a ordem determinada aleatoriamente. Para análise estatística, foi utilizado o teste t pareado, a correlação de Pearson e o Bland-Altman com nível de significância de 5 por cento. RESULTADOS: As médias encontradas durante as duas medidas das pressões nasais foram de 125±42,4 cmH2O para o aparelho importado e de 131,7±28,7 cmH2O para o nacional. A análise de Pearson demonstrou uma correlação significativa entre as médias, com um coeficiente r=0,63. Os valores médios não apresentaram diferenças significativas pelo teste t pareado (p>0,05). Na análise de Bland-Altman, encontrou-se um BIAS igual a 7 cm H2O, desvio-padrão de 32,9 cmH2O para o DP e um intervalo de confiança de -57,5 cmH2O até 71,5 cmH2O. CONCLUSÃO: Os resultados encontrados sugerem que o manovacuômetro eletrônico nacional é viável e seguro para realização do sniff teste em sujeitos saudáveis.

BACKGROUND: The measurement of nasal inspiratory pressure, known as the sniff test, was developed as a new test of inspiratory muscle strength, mainly used in neuromuscular conditions. The test is easy to be performed and noninvasive. Despite the clinical importance of assessment of nasal inspiratory pressure a national equipment is not available to assess it. OBJECTIVES: To compare a national with a foreign manovacuometer in assessing the nasal inspiratory pressure (sniff test) in healthy subjects. METHODS: 18 subjects were evaluated (age 21.44±2.8 years, BMI 23.4±2.5 kg/m² , FVC 102.1±10.3 percent pred, FEV1 98.4±1 percent pred). We performed two measures of nasal inspiratory pressure using two different manovacuometer: a national and a foreign. All subjects performed the tests at the same time of day, in different days being the order of the testes established randomly. It was used the paired t test, Pearson correlation and the Bland-Altman plots for statistical analysis considering a 5 percent significance level. RESULTS: The averages observed for the two measures of nasal pressures were 125±42.4 cmH2O for the foreign equipment, and 131.7±28.7 cmH2O for the national equipment. The Pearson correlation showed significant correlation between the means with a coefficient of r=0.63. The t test showed no significant differences between both measurements (p>0,05). The BIAS±SD found in Bland-Altman plot analysis was 7 cmH2O with limits of agreement between -57.5 cmH2O and 71.5 cmH2O. CONCLUSION: The results suggest that the national electronic device is feasible and safe to the sniff test measurement in healthy subjects.

Relação entre pressão inspiratória nasal e pressão inspiratória máxima em pacientes com distrofia miotônica / Relation between inspiratory nasal pressure and maximal inspiratory pressure in muscular myotonic dystrophy patients

Introdução: A Distrofia Miotônica (OM) é uma doença neuromuscular multissistêmica que cursa com diminuição progressiva da força muscular respiratória, sendo este um importante fator para o desenvolvimento de complicações pulmonares. Objetivo: O objetivo deste estudo foi avaliar as correlações e a concordância entre as medidas de sniff nasal inspiratory pressure (SNIP) e a pressão inspiratória máxima (Plmáx), assim como a precisão da associação destes testes na classificação de comprometimento muscular inspiratório em pacientes com OM. Método: Foram avaliados 20 pacientes (idade 41 ± 17 anos, IMC 23,3 ± 5,7 kg/m',CVF 75 ± 15 % pred, VEFj 76 ± 20%pred e VEF/CVF 83 ± 10%), os quais foram classificados em grau de acometimento muscular. Realizaram espirometria, sniff teste e Plmáx. Resultados: A análise mostrou uma média de SNIP de 76 ± 23 cmHp (78± 27% pred) e Plmáx de 74 ± 30 cmH,O (69 ± 23 % pred.). Encontramos uma correlação significativa e uma fraca concordância entre Plmáx e SNIP. Quando considerado apenas a avaliação da Plmáx, 70% (14 pacientes) da amostra apresentou comprometimento muscular inspiratório, e quando somente o modelo de sniff teste foi considerado, esse resultado foi encontrado em 30% dos pacientes. Na associação dos testes, 30% dos pacientes apresentaram comprometimento muscular inspiratório. Conclusão: Sugerimos que a associação das avaliações de SNIP e Plmáx pode aumentar a precisão na classificação de comprometimento muscular inspiratório em pacientes com DM. As medidas de SNIP e Plmáx mostraram não ser intercambiáveis, mas complementares na avaliação da força muscular inspiratória em pacientes com distrofia miotônica, principalmente aqueles com comprometimento muscular orofacial. IMC: Índice de massa corpórea; CVF: Capacidade Vital Forçada; VEF,: Volume expiratório forçado no primeiro segundo; VEF/CVF: Índice de Tiffeneau- Razão entre volume expiratório forçado no primeiro segundo e capacidade vital forçada.

Introduction: Myotonic Oystrophy (MO) is a neuromuscular multisystem disease that leads to progressive decrease in respiratory muscle strength, which is an important factor for the development of pulmonary complications. Objective: to evaluate the relationship between sniff nasal inspiratory pressure (SNIP and maximal inspiratory pressure (MIP) and the accuracy of these tests in the classification of inspiratory muscle impairment in patients with DM. Method: Twenty patients were evaluated (age 41 ± 17 years, BMI 23.3 ± 5.7 kg/m2, FVC 75 ± 15% pred, FEVj 76 ± 20% pred and FEV/FVC 83 ± 10%), which were classified as degree of muscular involvement. Spirometry, sniff test and MIP were developed. Results: The analysis showed a mean SNIP of 76 ± 23 cmHp (78 ± 27% pred) and MIP was 74 ± 30 cmH20(69 ± 23% pred). We found a significant correlation and a weak agreement between MIP and SNIP. When considering only the evaluation of the MIP, 70% (14 patients) of the sample had impaired inspiratory muscle, and only when the sniff test model was considered, this result was achieved in 30% of patients. In the association tests, 30% of patients had impaired inspiratory muscle. Conclusion: We suggest that the association assessments of SNIP and MIP can increase the accuracy in the classification of inspiratory muscle impairment in patients with MD. Measures of SNIP and MIP were shown not to be interchangeable, but complementary in the evaluation of muscle strength in patients with myotonic dystrophy, particularly those with orofacial muscle involvement. BMI: Body mass index; FVC: forced vitai capacity; FEV,: Forced expiratory volume in the first second; FEV/FVC: Tiffeneau index- Ratio between forced expiratory volume in the first second and forced vital capacity.

Confiabilidade do teste da caminhada de seis minutos em pacientes com miastenia gravis generalizada / Reliability of the six-minute walk test in patients with generalized myasthenia gravis

Este estudo objetivou determinar a confiabilidade do teste da caminhada de seis minutos (TC6M) como um teste de capacidade funcional em pacientes com miastenia gravis generalizada (MG). Selecionamos 11 pacientes com MG – 5 homens, 6 mulheres – com idade de 55±9 anos. Três TC6M em diferentes dias, onde avaliamos a distância percorrida, sensação de dispnéia, freqüência cardíaca e a saturação de oxigênio. As distâncias percorridas foram: 498±80 metros (99,4±8,4% pred.), 517±68 metros (103±10% pred.) e 520±61 metros (104±12% pred.), respectivamente para o TC6M1, TC6M2 e TC6M3. Encontramos uma alta confiabilidade relativa com um coeficiente de correlação interclasse (CCI) maior que 0,90 entre as provas TC6M1-TC6M2: 0,960, TC6M1-TC6M3: 0,945 e TC6M2-TC6M3: 0,970; uma confiabilidade absoluta de 4%, 3.5% e 4,8% com uma reprodutibilidade de 11%, 9,8% e 13,4% para o TC6M1, TC6M2 e TC6M3 respectivamente. O valor médio do Bias e os limites superiores e inferiores de concordância do Bland-Altman mostraram-se clinicamente aceitáveis: 3±25 metros (95%IC: 52,3-46,2), 19±33 metros (95%IC: 47,3-85,3), 22±40 metros (95%IC: 57,4-65,5) para o primeiro, segundo e terceiro teste. Concluímos que o TC6M mostrou-se seguro, confiável e reprodutível, podendo ser executado para avaliação e seguimento da tolerância ao exercício em pacientes com MG generalizada...

The objective of this study is to investigate the reliability of the six minutes walking test (6MWT) in generalized myasthenia gravis. Eleven patients with generalized MG (5M,6F), with age 55±9 years, BMI 28±3,5 kg/m2, FVC 86±14% pred. and VEF1 85±16% pred. were studied. Distance walked, dyspnea, heart rate and oxygen saturation were measure in three 6MWT in different days. The distance walked in meters were 498±80 meters (99,4±8,4% pred.), 517±68 meters (103±10% pred.) and 520±61 meters (104±12% pred.), for 6MWT1, 6MWT2 e 6MWT3 respectively. A high reliability was found with interclasse coefficient correlation > 0,90 between the tests, 6MWT1-6MWT2: 0,96, 6MWT1-6MWT3: 0,95 and 6MWT2-6MWT3: 0,97; an absolute reliability of 4%, 3,5% and 4,8% to 6MWT1, 6MWT2 and 6MWT3 and a good repeatability of 11%, 9,8% and 13,4% for each test, respectively. Bias medium value and superior and inferior limits of agreement from Bland-Altman reveals clinically acceptability: 3±25 meters (95%CI: 52,3-46,2), 19±33 meters (95%CI: 47,3-85,3), 22±40 meters (95%CI: 57,4-65,5) for first to second, first to third and second to third tests respectively. We conclude that the 6MWT demonstrated to be safe, reliable and reproducible in generalized myasthenia gravis, can be performed to assess exercise tolerance and in these patients...