Inflammation and oxidative stress in heart failure: effects of exercise intensity and duration.

Although acute exercise is apparently pro-inflammatory and increases oxidative stress, it can promote the necessary stress stimulus to train chronic adaptations in patients with chronic heart failure (CHF). This study aimed to compare the effects of exercise intensity and duration on the inflammatory markers soluble tumor necrosis factor receptor (sTNFR1) and interleukin-6 (IL-6), and on oxidative stress [malondialdehyde (MDA) and antioxidant enzymes: catalase (CAT) and superoxide dismutase (SOD)] in individuals with CHF. Eighteen patients performed three exercise sessions: 30 min of moderate-intensity (M30) exercise, 30 min of low-intensity (L30) exercise, and 45 min of low-intensity (L45) exercise. Blood analysis was performed before exercise (baseline), immediately after each session (after), and 1 h after the end of each session (1h after). Thirty min of M30 exercise promoted a larger stressor stimulus, both pro-inflammatory and pro-oxidative, than that promoted by exercises L30 and L45. This was evidenced by increased sTNFR1 and MDA levels after exercise M30. In response to this stressor stimulus, 1 h after exercise, there was an increase in IL-6 and CAT levels, and a return of sTNFR1 to baseline levels. These findings suggest that compared with the duration of exercise, the exercise intensity was an important factor of physiologic adjustments.

Inspiratory muscular weakness is most evident in chronic stroke survivors with lower walking speeds.

BACKGROUND: Respiratory muscular weakness and associated changes in thoracoabdominal motion have been poorly studied in stroke subjects, since the individuals' functional levels were not previously considered in the investigations. AIM: To investigate the breathing patterns, thoracoabdominal motion, and respiratory muscular strength in chronic stroke subjects, who were stratified into two groups, according to their walking speeds. DESIGN: Cross-sectional, observational study. SETTING: University laboratory. POPULATION: Eighty-nine community-dwelling chronic stroke subjects METHODS: The subjects, according to their gait speeds, were stratified into community (gait speed ≥0.8 m/s) and non-community ambulators (gait speed <0.8 m/s). Variables related to pulmonary function, breathing patterns, and thoracoabdominal motions were assessed. Measures of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were obtained and were compared with the reference values for the Brazilian population. The MIP and MEP values were expressed as percentages of the predicted values. Mann-Whitney-U or independent Student t-tests were employed to compare the differences between the two groups for the selected variables. RESULTS: No significant between-group differences were found for the variables related to the breathing patterns and thoracoabdominal motions (0.01 < z/t < 1.51; 0.14

Electromyographic activity of sternocleidomastoid muscle in patients with Parkinson's disease.

The aim of this study was to evaluate the effect of administration of levo-dopa, which means without effect-off state and under effect-on state, on the sternocleidomastoid muscle electromyographic activity (SCM-EA) in patients with Parkinson's disease (PD) at rest and to compare it to asymptomatic subjects. Ten patients with PD, mean age 64.6+/-6.2 (SD) years and nine asymptomatic subjects, mean age 61.4+/-5.9 (SD) years were studied. The SCM-EA was evaluated during maximal inspiratory pressure and breathing at rest through surface electromyography. Statistical analysis was performed with t-test (anthropometric data and SCM-EA of patients in off state to asymptomatic), Mann-Whitney (SCM-EA of patients in on state to asymptomatic) and Wilcoxon test (SCM-EA off and on states). The effect size index (d) was calculated for statistically significant differences. There were no significant differences in SCM electromyographic activity between patients with PD comparing off to on (p=0.13) or among on state to asymptomatic subjects (p=0.06). However, when subjects with PD in off where compared to asymptomatic there was a significantly higher SCM electromyographic activity (p=0.03, d=1.09). These patients, without levo-dopa effect, when compared with asymptomatic subjects, present a significantly higher electromyographic activity of SCM, the main accessory respiratory muscle, which could be related to an increased work of breathing.

Breathing pattern and thoracoabdominal motion during exercise in chronic obstructive pulmonary disease.

Subjects with chronic obstructive pulmonary disease (COPD) present breathing pattern and thoracoabdominal motion abnormalities that may contribute to exercise limitation. Twenty-two men with stable COPD (FEV1 = 42.6 +/- 13.5% predicted; age 68 +/- 8 years; mean +/- SD) on usual medication and with at least 5 years of diagnosis were evaluated at rest and during an incremental cycle exercise test (10 watts/2 min). Changes in respiratory frequency, tidal volume, rib cage and abdominal motion contribution to tidal volume and the phase angle that measures the asynchrony were analyzed by inductive respiratory plethysmography at rest and during three levels of exercise (30-50, 70-80, and 100% maximal work load). Repeated measures ANOVA followed by pre-planned contrasts and Bonferroni corrections were used for analyses. As expected, the greater the exercise intensity the higher the tidal volume and respiratory frequency. Abdominal motion contributed to the tidal volume increase (rest: 49.82 +/- 11.19% vs exercise: 64.15 +/- 9.7%, 63.41 +/- 10%, and 65.56 +/- 10.2%, respectively, P < 0.001) as well as the asynchrony [phase angle: 11.95 +/- 7.24 degrees at rest vs 22.2 +/- 15 degrees (P = 0.002), 22.6 +/- 9 degrees (P < 0.001), and 22.7 +/- 8 degrees (P < 0.001), respectively, at the three levels of exercise]. In conclusion, the increase in ventilation during exercise in COPD patients was associated with the major motion of the abdominal compartment and with an increase in the asynchrony independent of exercise intensity. It suggests that cycling exercise is an effective way of enhancing ventilation in COPD patients.

Padrão respiratório e movimento toracoabdominal de crianças respiradoras orais / Breathing pattern and thoracoabdominal motion in mouth-breathing children

OBJETIVO: Caracterizar o padrão respiratório e o movimento toracoabdominal de crianças respiradoras orais, na faixa etária entre oito e dez anos, e compará-lo ao de seus pares respiradoras nasais. MÉTODOS: Estudo observacional realizado em laboratório universitário. O número amostral calculado com base em um estudo piloto com dez crianças em cada grupo, perfazendo um total de 20 crianças, foi de 50 para um nível de significância de 0,05 e um poder estatístico de 0,80. Participaram do estudo 26 crianças respiradoras orais e 25 respiradoras nasais. A pletismografia respiratória por indutância calibrada foi o instrumento utilizado para a análise das seguintes variáveis, entre outras: freqüência respiratória (FR), contribuição da caixa torácica para o volume corrente ( por centoCT/Vc), ângulo de fase (Angfase) e a razão entre o tempo para alcançar o pico de fluxo inspiratório e o tempo inspiratório (PifT/Ti). A saturação periférica da hemoglobia em oxigênio (SpO2) foi medida pela oximetria de pulso. A análise estatística foi realizada por meio do teste t de Student para grupos independentes e do teste U de Mann-Whitney, em função da distribuição das variáveis. RESULTADOS: No total, 4.816 ciclos respiratórios foram analisados, sendo 2.455 de respiradores orais e 2.361 de respiradores nasais, com média de 94 ciclos por criança. Não houve diferença significativa entre os grupos nas variáveis estudadas (FR=20,00±2,68 versus 20,73±2,58, p=0,169; por centoCT/Vc=39,30±11,86 versus 38,36±10,93, p=0,769; Angfase=14,53±7,97 versus 13,31±7,74, p=0,583; PifT/Ti=57,40±7,16 versus 58,35±5,99, p=0,610; SpO2=96,42±1,52 por cento versus 96,88±1,01 por cento, p=0,208; respectivamente). CONCLUSÕES: Estes resultados sugerem que as crianças respiradoras orais apresentam padrão respiratório e movimento toracoabdominal semelhantes às de respiradores nasais de mesma faixa etária.

OBJECTIVE: To characterize the breathing pattern and thoracoabdominal motion of mouth-breathing children aged between eight and ten years and to compare these characteristics with those of nose-breathing children of the same ages. METHODS: This observational study was carried out in a university laboratory. The sample size of 50 subjects was estimated based on the results of a pilot study with ten children in each group (total of 20 children) and considering a significance level of 0.05 and statistical power of 0.80. Twenty-six mouth-breathing and 25 nose-breathing children participated. Calibrated respiratory inductive plethysmography was used to analyze the following variables, among others: respiratory frequency (f), rib cage contribution towards tidal volume ( percentRC/Vt), phase angle (PhAng) and the ratio between time taken to reach peak inspiratory flow and total inspiratory time (PifT/Ti). Peripheral oxygen saturation of hemoglobin (SpO2) was measured using pulse oximetry. Statistical analysis was performed using the Student's t test for independent groups or the Mann-Whitney U test, according to the sample distribution of the variables. RESULTS: A total of 4,816 respiratory cycles were analyzed: 2,455 from mouth-breathers and 2,361 from nose-breathers, with a mean of 94 cycles per child. No statistically significant differences were observed between the groups, for the variables studied (f=20.00±2.68 versus 20.73±2.58, p=0.169; percentRC/Vt=39.30±11.86 versus 38.36±10.93, p=0.769; PhAng=14.53±7.97 versus 13.31±7.74, p=0.583; PifT/Ti=57.40±7.16 versus 58.35±5.99, p=0.610; SpO2=96.42±1.52 percent versus 96.88± 1.01 percent, p=0.208; respectively). CONCLUSIONS: These results suggest that mouth-breathing children show breathing patterns and thoracoabdominal motion that are similar to those of nose-breathing children in the same age group.

Breathing pattern and thoracoabdominal motion during exercise in chronic obstructive pulmonary disease

Subjects with chronic obstructive pulmonary disease (COPD) present breathing pattern and thoracoabdominal motion abnormalities that may contribute to exercise limitation. Twenty-two men with stable COPD (FEV1 = 42.6 ± 13.5 percent predicted; age 68 ± 8 years; mean ± SD) on usual medication and with at least 5 years of diagnosis were evaluated at rest and during an incremental cycle exercise test (10 watts/2 min). Changes in respiratory frequency, tidal volume, rib cage and abdominal motion contribution to tidal volume and the phase angle that measures the asynchrony were analyzed by inductive respiratory plethysmography at rest and during three levels of exercise (30-50, 70-80, and 100 percent maximal work load). Repeated measures ANOVA followed by pre-planned contrasts and Bonferroni corrections were used for analyses. As expected, the greater the exercise intensity the higher the tidal volume and respiratory frequency. Abdominal motion contributed to the tidal volume increase (rest: 49.82 ± 11.19 percent vs exercise: 64.15 ± 9.7 percent, 63.41 ± 10 percent, and 65.56 ± 10.2 percent, respectively, P < 0.001) as well as the asynchrony [phase angle: 11.95 ± 7.24° at rest vs 22.2 ± 15° (P = 0.002), 22.6 ± 9° (P < 0.001), and 22.7 ± 8° (P < 0.001), respectively, at the three levels of exercise]. In conclusion, the increase in ventilation during exercise in COPD patients was associated with the major motion of the abdominal compartment and with an increase in the asynchrony independent of exercise intensity. It suggests that cycling exercise is an effective way of enhancing ventilation in COPD patients.

Pressões respiratórias máximas: valores encontrados e preditos em indivíduos saudáveis / Maximal respiratory pressures: actual and predicted values in healthy subjects

OBJETIVO: Comparar os valores encontrados de pressões respiratórias máximas (pressão inspiratória máxima-PImáx e pressão expiratória máxima-PEmáx) em uma amostra de indivíduos saudáveis de Minas Gerais com valores preditos pelas equações propostas por Neder et al.³. MÉTODOS: Por meio de um manovacuômetro analógico, foram estudados 100 indivíduos saudáveis (54 mulheres, 46 homens), com idade entre 20-80 anos, recrutados no estado de Minas Gerais - Brasil. A análise estatística foi realizada com testes paramétricos ou não-paramétricos, dependendo da distribuição das variáveis, considerando significativo p< 0,05. RESULTADOS: PImáx em mulheres: a média dos valores encontrados foi significativamente menor que a média dos preditos (68,24 ± 29,48 x 86,53 ± 8,76; p= 0,000) e houve correlação de moderada magnitude e significativa (r= 0,557; p< 0,000); PImáx em homens: não houve diferença significativa entre os valores encontrados e preditos (104,67 ± 42,66 x 116,78 ± 14,02; p= 0,055) e houve correlação de baixa magnitude e não significativa (r= 0,236; p= 0,115); PEmáx em mulheres: não houve diferença significativa entre os valores encontrados e preditos (80,37 ± 33,32 x 85,88 ± 10,90; p= 0,164) e houve correlação de baixa magnitude e não significativa (r= 0,149; p= 0,283); PEmáx em homens: a média dos valores encontrados foi significativamente maior que a média dos preditos (142,28 ± 43,89 x 126,30 ± 14,19; p= 0,017) e houve correlação não significativa de baixa magnitude (r= 0,159; p= 0,290). CONCLUSÃO: Considerando que para haver concordância entre os valores encontrados e preditos é preciso não haver diferença e haver correlação entre os valores, as equações propostas por Neder et al.³ não foram capazes de predizer os valores de PImáx e PEmáx na população estudada.

OBJECTIVE: To compare actual values for maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) found in a sample of healthy individuals from the State of Minas Gerais (Brazil) with the values predicted from the equations put forward by Neder et al.³. METHOD: Using an analog manovacuometer, 100 healthy subjects (54 women and 46 men aged 20-80 years old) were studied. Statistical analysis was performed using parametric or non-parametric tests, depending on the distribution of the variables, and p< 0.05 was considered to be significant. RESULTS: For MIP in women, the mean of the actual values was significantly lower than the mean of the predicted values (68.24 ± 29.48 vs. 86.53 ± 8.76; p= 0.000) and there was a moderate and significant correlation (r= 0.557; p< 0.000). For MIP in men, no significant difference was observed between the actual and predicted values (104.67 ± 42.66 vs. 116.78 ± 14.02; p= 0.055) and there was a low and non-significant correlation (r= 0.236; p= 0.115). For MEP in women, there was no significant difference between the actual and predicted values (80.37 ± 33.32 vs. 85.88 ± 10.90; p= 0.164) and there was a low and non-significant correlation (r= 0.149; p= 0.283). For MEP in men, the mean of the actual values was significantly higher than the mean of the predicted values (142.28 ± 43.89 vs. 126.30 ± 14.19; p= 0.017) and there was a low and non-significant correlation (r= 0.159; p= 0.290). CONCLUSION: Considering that concordance between actual and predicted values requires the lack of difference and the existence of correlation between them, the equations proposed by Neder et al.³ were not successful in predicting MIP and MEP values in the population studied.

Breathing pattern, thoracoabdominal motion and muscular activity during three breathing exercises

The objective of the present study was to evaluate breathing pattern, thoracoabdominal motion and muscular activity during three breathing exercises: diaphragmatic breathing (DB), flow-oriented (Triflo II) incentive spirometry and volume-oriented (Voldyne) incentive spirometry. Seventeen healthy subjects (12 females, 5 males) aged 23 ± 5 years (mean ± SD) were studied. Calibrated respiratory inductive plethysmography was used to measure the following variables during rest (baseline) and breathing exercises: tidal volume (Vt), respiratory frequency (f), rib cage contribution to Vt (RC/Vt), inspiratory duty cycle (Ti/Ttot), and phase angle (PhAng). Sternocleidomastoid muscle activity was assessed by surface electromyography. Statistical analysis was performed by ANOVA and Tukey or Friedman and Wilcoxon tests, with the level of significance set at P < 0.05. Comparisons between baseline and breathing exercise periods showed a significant increase of Vt and PhAng during all exercises, a significant decrease of f during DB and Voldyne, a significant increase of Ti/Ttot during Voldyne, and no significant difference in RC/Vt. Comparisons among exercises revealed higher f and sternocleidomastoid activity during Triflo II (P < 0.05) with respect to DB and Voldyne, without a significant difference in Vt, Ti/Ttot, PhAng, or RC/Vt. Exercises changed the breathing pattern and increased PhAng, a variable of thoracoabdominal asynchrony, compared to baseline. The only difference between DB and Voldyne was a significant increase of Ti/Ttot compared to baseline. Triflo II was associated with higher f values and electromyographic activity of the sternocleidomastoid. In conclusion, DB and Voldyne showed similar results while Triflo II showed disadvantages compared to the other breathing exercises.

Breathing pattern, thoracoabdominal motion and muscular activity during three breathing exercises.

The objective of the present study was to evaluate breathing pattern, thoracoabdominal motion and muscular activity during three breathing exercises: diaphragmatic breathing (DB), flow-oriented (Triflo II) incentive spirometry and volume-oriented (Voldyne) incentive spirometry. Seventeen healthy subjects (12 females, 5 males) aged 23 +/- 5 years (mean +/- SD) were studied. Calibrated respiratory inductive plethysmography was used to measure the following variables during rest (baseline) and breathing exercises: tidal volume (Vt), respiratory frequency (f), rib cage contribution to Vt (RC/Vt), inspiratory duty cycle (Ti/Ttot), and phase angle (PhAng). Sternocleidomastoid muscle activity was assessed by surface electromyography. Statistical analysis was performed by ANOVA and Tukey or Friedman and Wilcoxon tests, with the level of significance set at P < 0.05. Comparisons between baseline and breathing exercise periods showed a significant increase of Vt and PhAng during all exercises, a significant decrease of f during DB and Voldyne, a significant increase of Ti/Ttot during Voldyne, and no significant difference in RC/Vt. Comparisons among exercises revealed higher f and sternocleidomastoid activity during Triflo II (P < 0.05) with respect to DB and Voldyne, without a significant difference in Vt, Ti/Ttot, PhAng, or RC/Vt. Exercises changed the breathing pattern and increased PhAng, a variable of thoracoabdominal asynchrony, compared to baseline. The only difference between DB and Voldyne was a significant increase of Ti/Ttot compared to baseline. Triflo II was associated with higher f values and electromyographic activity of the sternocleidomastoid. In conclusion, DB and Voldyne showed similar results while Triflo II showed disadvantages compared to the other breathing exercises.

Teste de caminhada de seis minutos em diferentes faixas etárias e índices de massa corporal / Six-minute walk test at different ages and body mass index

CONTEXTUALIZAÇÃO: Os testes submáximos têm sido escolhidos para avaliar o desempenho funcional por serem práticos e de baixo custo. OBJETIVO: Correlacionar a distância caminhada no teste de caminhada de 6 minutos com idade e índice de massa corporal e verificar a necessidade de aplicação do segundo teste. MÉTODOS: 122 indivíduos brasileiros, saudáveis, sedentários, com idade entre 18 e 80 anos realizaram dois testes de caminhada, que consistia em caminhar a maior distância possível durante seis minutos. O peso e altura foram avaliados para cálculo do índice de massa corporal. Os dados foram expressos como média e desvio-padrão. As análises estatísticas foram realizadas pelos testes t de Student, ANOVA e Correlação de Pearson. RESULTADOS: Foi encontrada forte correlação entre as duas distâncias caminhadas quando todos os sujeitos foram analisados sem divisão de faixas etárias. Ao dividir os sujeitos em três grupos, por faixas etárias, observou-se diferença significante (p< 0,05) entre as distâncias caminhadas pelos grupos: grupo 1 (20 a 40 anos)= 645,19 m ± 80,78, grupo 2 (41 a 60 anos)= 540,68 m ± 59,74 e a grupo 3 (>60 anos)= 457,39 m ± 64,1. Os sujeitos com índice de massa corpórea < 25 caminharam a maior distância (565,45 m ± 101,56) quando comparados aos sujeitos de índice de massa corpórea >25 e <35 (492,93 m ± 73,18) e de índice de massa corpórea >35 (457,35 m ± 92,18). CONCLUSÃO: Os resultados encontrados neste estudo confirmam a reprodutibilidade do teste de caminhada de seis minutos e a sensibilidade que o teste tem de avaliar o desempenho e a capacidade funcional de indivíduos com diferentes faixas etárias e índice de massa corporal.

INTRODUCTION: Submaximal tests have been chosen to evaluate functional status because of their practicality and low cost. OBJECTIVE:To correlate the distance walked during a six-minute test with age and body mass index, and to verify the need for applying a second test. METHOD: 122 healthy Brazilians aged between 18 and 80 years who had a sedentary lifestyle performed two tests that consisted of walking as far as possible over a six-minute period. Their weights and heights were assessed by calculating the body mass index. The data were expressed as means and standard deviations. The statistical analyses were performed using Student's t test, ANOVA and Pearson's correlation. RESULTS: A strong correlation was found between the two distances walked when all the subjects were analyzed without age divisions. When the subjects were divided into three groups according to age, there were significant differences (p< 0.05) between the distances walked by the groups: Group 1 (20 to 40 years)= 645.19 m ± 80.78, Group 2 (40 to 60 years)= 540.68 m ± 59.74 and Group 3 (>60 years)= 457.39 m ± 64.1. The subjects with body mass index <25 walked longer distances (565.45 m ± 101.56) than either those with body mass index >25 and <35 (492.93 m ± 73.18) or those with body mass index >35 (457.35 m ± 92.18). CONCLUSION: The results found in this study confirm the reproducibility of the six-minute walk test and the sensitivity that this test has for evaluating the performance and functional capacity of individuals with different ages and body mass index.

Comparacao do padrao respiratorio entre adultos e idosos saudaveis / Comparison of breathing pattern between healty adults and elderly people

O sistema respiratorio sofre alteracoes inerentes ao envelhecimento . O conhecimento dessas modificacoes contribui para a deteccao e prevencao de disfuncoes respiratorias em idosos. Objetivo: comparar o padrao respiratorio entre adultos e idosos saudaveis. Metodo: dezoito idosos (60-80 anos) e dezenove adultos (18-40 anos) foram estudados. A pletismografia respiratoria por indutancia calibrada foi utilizada para medir as variaveis volume corrente (VT), frequencia respiratoria(f), ventilacao minuto (VE), porcentagem do tempo inspiratorio em relacao ao tempo total do ciclo respiratorio (TI/TTOT), fluxo inspiratorio medio (VT/TI), contribuicao da caixa toracica (CT/VT) e do abdome (AB/VT) para o volume corrente. A oximetria de pulso foi utilizada para medir a saturacao periferica da hemoglobina em oxigenio (SpO2) e frequencia cardiaca (FC). As medidas foram registradas em repouso, com os sujeitos posicionados em decubito dorsal a 30o.grau de inclinacao de tronco. A analise estatistica aplicada foi teste t de Student para grupos independentes, considerando significativi p<0,05. Resultados: nao houve diferenca estatistica entre os grupos estudados em relacao ao VT(p=0,13) e a f(p=0,10); a contribuicao toracoabdominal foi semelhante entre adultos e idosos (p=0,79); a SpO2, foi significativamente menor nos idosos quando comparada a dos adultos (p=0,0002). Conclusao: os resultados mostraram que nao houve diferenca do padrao respiratorio entre os adultos e os idosos avaliados em repouso em decubito dorsal a 30o.grau de inclinacao de tronco, , sugerindo que o processo de envelhecimento do sistema respiratorio na populacao estudada nao provocou grande impacto nos parametros analisados

Assessment of tidal volume and thoracoabdominal motion using volume and flow-oriented incentive spirometers in healthy subjects.

The objective of the present study was to evaluate incentive spirometers using volume- (Coach and Voldyne) and flow-oriented (Triflo II and Respirex) devices. Sixteen healthy subjects, 24 +/- 4 years, 62 +/- 12 kg, were studied. Respiratory variables were obtained by respiratory inductive plethysmography, with subjects in a semi-reclined position (45 masculine). Tidal volume, respiratory frequency, minute ventilation, inspiratory duty cycle, mean inspiratory flow, and thoracoabdominal motion were measured. Statistical analysis was performed with Kolmogorov-Smirnov test, t-test and ANOVA. Comparison between the Coach and Voldyne devices showed that larger values of tidal volume (1035 +/- 268 vs 947 +/- 268 ml, P = 0.02) and minute ventilation (9.07 +/- 3.61 vs 7.49 +/- 2.58 l/min, P = 0.01) were reached with Voldyne, whereas no significant differences in respiratory frequency were observed (7.85 +/- 1.24 vs 8.57 +/- 1.89 bpm). Comparison between flow-oriented devices showed larger values of inspiratory duty cycle and lower mean inspiratory flow with Triflo II (0.35 +/- 0.05 vs 0.32 +/- 0.05 ml/s, P = 0.00, and 531 +/- 137 vs 606 +/- 167 ml/s, P = 0.00, respectively). Abdominal motion was larger (P < 0.05) during the use of volume-oriented devices compared to flow-oriented devices (52 +/- 11% for Coach and 50 +/- 9% for Voldyne; 43 +/- 13% for Triflo II and 44 +/- 14% for Respirex). We observed that significantly higher tidal volume associated with low respiratory frequency was reached with Voldyne, and that there was a larger abdominal displacement with volume-oriented devices.

Assessment of tidal volume and thoracoabdominal motion using volume and flow-oriented incentive spirometers in healthy subjects

The objective of the present study was to evaluate incentive spirometers using volume- (Coach and Voldyne) and flow-oriented (Triflo II and Respirex) devices. Sixteen healthy subjects, 24 ± 4 years, 62 ± 12 kg, were studied. Respiratory variables were obtained by respiratory inductive plethysmography, with subjects in a semi-reclined position (45°). Tidal volume, respiratory frequency, minute ventilation, inspiratory duty cycle, mean inspiratory flow, and thoracoabdominal motion were measured. Statistical analysis was performed with Kolmogorov-Smirnov test, t-test and ANOVA. Comparison between the Coach and Voldyne devices showed that larger values of tidal volume (1035 ± 268 vs 947 ± 268 ml, P = 0.02) and minute ventilation (9.07 ± 3.61 vs 7.49 ± 2.58 l/min, P = 0.01) were reached with Voldyne, whereas no significant differences in respiratory frequency were observed (7.85 ± 1.24 vs 8.57 ± 1.89 bpm). Comparison between flow-oriented devices showed larger values of inspiratory duty cycle and lower mean inspiratory flow with Triflo II (0.35 ± 0.05 vs 0.32 ± 0.05 ml/s, P = 0.00, and 531 ± 137 vs 606 ± 167 ml/s, P = 0.00, respectively). Abdominal motion was larger (P < 0.05) during the use of volume-oriented devices compared to flow-oriented devices (52 ± 11 percent for Coach and 50 ± 9 percent for Voldyne; 43 ± 13 percent for Triflo II and 44 ± 14 percent for Respirex). We observed that significantly higher tidal volume associated with low respiratory frequency was reached with Voldyne, and that there was a larger abdominal displacement with volume-oriented devices.

Sazonalidade e asma infantil: impacto em indicadores funcionais e respiratórios / Seasonal variations and child asthma: impact on functional and respiratory indicators

A asma e uma enfermidade cronica de alta incidencia na populacao infantil e associada a elevadas taxas de hospitalizacao e de procura por servicos medicos. Diferencas ambientais decorrentes de variacoes sazonais podem estar realacionadas ao agravamento da doenca. O objetivo deste estudo foi avaliar longitudinalmente o impacto da sazonalidade no perfil respiratorio e no desempenho de atividades funcionais de criancas asmaticas de 1 a 4 anos. O estudo foi iniciado com 60 criancas alocadas em dois grupos (asma n=30 e controle n=30), cujos perfis funcional e respiratorio foram avaliados em tres estacoes: inverno, primavera e verao. As criancas asmaticas faziam parte do Programa Crianca que Chia, da prefeitura de belo Horizonte, MG. Foram urtilizados um exame clinico sobre o perfil respiratorio das criancas e um teste infantil padronozado (PEDI) para avliar o desempenho das mesmas em atividades de autocuidado, mobilidade e funcao social. Modelos mistos do teste MANOVA, testes ANOVA e contrastes pre-planejados compararam os grupos nas variaveis quantitativas e testes qui-quadrado examinaram a associacao entre grupos e variaves respiratorias categoricas. Os resultados revelaram efeito significativo das estacoes, com desempenho funcional inferior no inverno para as criancas de ambos os grupos, comparado as outras duas estacoes. Associacoes significativas foram encontradas entre os grupos e a presenca de sintomas respiratorios, sendo que as criancas asmaticas apresentaram maior frequencia desses sintomas na primavera e no vera, quando comparadas com o grupo-controle. Apesar das diferencas observadas nos indicadores respiratorios, essas nao se manifestaram no desempenho funcional das criancas asmaticas, sugerindo que tais criancas apresentaram semelhante as do grupo-controle nas variaveis funcionais estudadas

Avaliacao do volume corrente da configuracao toracoabdominal durante o uso de espirometros de incentivo a volume e a fluxo, em sujeitos saudaveis: influencia da posicao corporal / Assessment of tidal volume and thoracoabdominal motion using volume and flow-oriented incentive spirometers in healthy subjects: influence of body position

O objetivo deste estudo foi avaliar a influencia da posicao corporal no volume correto e na configuracao toracoabdominal durante o uso de dois diferentes espirometros de incentivo (EI), um orientado a volume (Voldyne) e outro a fluxo (Triflo II). Foram estudado 20 participantes saudaveis, com conhecimento previo da tecnica de espirometria de incentivo. Foram medidos, por meio da pletismografia respiratoria por induntancia calibrada, volume corrente (Vc), ventilacao minuto, frequencia respiratoria, porcentagem do tempo inspiratorio em relacao ao tempo total do ciclo respiratorio, fluxo inspiratorio medio e contribuicao da caixa toracica (CT/Vc por cento) e do abdome (AB/Vc por cento) para o volume corrente. Essas variaveis foram registradas durante periodos de baseline e de uso dos EI,na posicao supino a 30º e a 45º de inclinacao da horizontal. A analise estatistica foi realizada por meio do teste ANOVA, com o pos-teste contraste. Os principais resultados foram: aumento significativo do Vc durante os periodos de espirometria, independente do espirometro de incentivo utilizado ou da posicao corporal, e diminuicao da ( AB/Vc por cento) nos periodos de espirometria em relacao aos periodos de baseline, exceto durante o uso do Voldyne a 30º, em que nao houve diferenca significativa na configuracao toracoabdominal. A influencia da posicao corporal na configuracao tracoabdominal, comparando-se 30º e 45º, so ocorreu durante o uso do Voldyne, sendo que a(AB/Vc por cento) foi maior a 30º. Comparando-se os EI, houve maior (AB/Vc por cento) com o uso do Voldyne, em ambas as posicoes. Os resultados do presente estudo sugerem que ha influencia da posicao corporal sobre a configuracao toracoabdominal, nao havendo entretanto, sobre o volume corrente.

Potentiation of the hypotensive effect of bradykinin by angiotensin-(1-7)-related peptides.

In this study, we evaluated the bradykinin potentiating activity and ACE inhibitory activity of several Ang-(1-7)-related peptides: Ang-(2-7), Ang-(3-7), Ang-(4-7), Ang-(1-6), Ang-(1-5) and the selective antagonist of Ang-(1-7): D-[Ala7]Ang-(1-7) (A-779). In vivo experiments were performed in freely moving Wistar rats. ACE activity was evaluated by a fluorometric assay in rat plasma using Hip-His-Leu as a substrate. Intravenous injections of Ang-(1-7) (2.2 nmol) transformed the effect of a single dose of bradykinin (1 nmol) into the effect produced by a double dose. A similar bradykinin potentiating activity was demonstrated for Ang-(2-7) and Ang-(3-7). On the other hand, Ang-(1-5), Ang-(1-6), Ang-(4-7) and A-779 did not change the hypotensive effect of bradykinin in doses ranging from 8 up to 25 nmols. The hypotensive effect of bradykinin was increased by intravenous infusion (0.3 ng/min) of Ang-(1-7) > Ang-(2-7) > Ang-(3-7). Conversely, Ang-(1-5), Ang-(1-6), Ang-(4-7) or A-779 did not change the hypotensive effect of bradykinin. ACE inhibition with Ang-(1-7) related peptides occurred in the order: Ang-(2-7) > or = Ang-(3-7) > Ang-(1-7) [>>] Ang-(1-5) > Ang-(4-7) > or = Ang-(1-6) > or = A-779. A-779 in concentrations up to 10(-5) M did not change the ACE inhibitory activity of Ang-(1-7). These results suggest that Ang-(1-7), Ang-(2-7) and Ang-(3-7) can modulate bradykinin actions in vivo. More important, our data pointed out that alternative mechanisms besides interaction with ACE are required to explain the bradykinin potentiating activity of Ang-(1-7).

Role of angiotensin-(1-7) in the modulation of the baroreflex in renovascular hypertensive rats.

In this study, we evaluated the effect produced by lateral ventricle (intracerebroventricular, I.C.V.) infusion of the selective angiotensin (Ang)-(1-7) antagonist, D-Ala7-Ang-(1-7) (A-779), in the modulation of the baroreflex control of heart rate in two-kidney, one clip renovascular hypertensive rats (2K1C) treated with the angiotensin-converting enzyme (ACE) inhibitor enalapril. Twenty days after the surgery to produce renovascular hypertension, I.C.V. cannulas were implanted in the rats with blood pressure (BP) greater than 145 mm Hg (n=33) and in sham-operated rats (n=32). Five days later, the rats were treated with enalapril (10 mg x kg(-1) x d(-1); 6 days, in the drinking water) or vehicle (tap water). On the sixth day of treatment, direct continuous BP recording and measurement of reflex changes in heart rate elicited by phenylephrine were made in conscious rats before and at 1 hour of I.C.V. infusion of saline (8 microL/h) or A-779 (4 microg/h). To evaluate the degree of ACE blockade produced by enalapril treatment, the pressor effect of Ang I (50 ng, I.V., and 100 ng, I.C.V.) and plasma ACE activity was determined. As expected, enalapril treatment in 2K1C produced a significant fall in BP, significant attenuation in the pressor response of Ang I (I.V.), and a reduction in plasma ACE activity. In addition, enalapril treatment increased the baroreflex sensitivity (0.76+/-0.04 versus 0.43+/-0.04 ms/mm Hg in 2K1C untreated rats). I.C.V. infusion of A-779 reverted the improvement in baroreflex sensitivity produced by enalapril treatment in 2K1C (from 0.80+/-0.07 to 0.42+/-0.08 ms/mm Hg) and also attenuated the baroreflex sensitivity in untreated 2K1C (0.36+/-0.05 versus 0.48+/-0.06 ms/mm Hg) and untreated sham-operated rats (1.21+/-0.05 versus 0.78+/-0.17 ms/mm Hg). These results suggest that central endogenous Ang-(1-7) is involved at least in part in the improvement of baroreflex sensitivity observed in 2K1C after peripheral chronic ACE inhibition.