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.

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.

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.

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.