G. M. Tomich

Pressões respiratórias máximas: valores encontrados e preditos em indivíduos saudáveis

Maximal respiratory pressures: actual and predicted values in healthy subjects 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.

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.

Effects of breathing exercises on breathing pattern and thoracoabdominal motion after gastroplasty

OBJECTIVE To evaluate breathing pattern and thoracoabdominal motion during breathing exercises. METHODS Twenty-four patients with class II or III obesity (18 women; 6 men) were studied on the second postoperative day after gastroplasty. The mean age was 37 +/- 11 years, and the mean BMI was 44 +/- 3 kg/m(2). Diaphragmatic breathing, incentive spirometry with a flow-oriented device and incentive spirometry with a volume-oriented device were performed in random order. Respiratory inductive plethysmography was used in order to measure respiratory variables and thoracoabdominal motion. RESULTS Comparisons among the three exercises showed significant differences: tidal volume was higher during incentive spirometry (with the flow-oriented device or with the volume-oriented device) than during diaphragmatic breathing; the respiratory rate was lower during incentive spirometry with the volume-oriented device than during incentive spirometry with the flow-oriented device; and minute ventilation was higher during incentive spirometry (with the flow-oriented device or with the volume-oriented device) than during diaphragmatic breathing. Rib cage motion did not vary during breathing exercises, although there was an increase in thoracoabdominal asynchrony, especially during incentive spirometry with the flow-oriented device. CONCLUSIONS Among the breathing exercises evaluated, incentive spirometry with the volume-oriented device provided the best results, because it allowed slower, deeper inhalation.

Changes in breathing pattern and thoracoabdominal motion after bariatric surgery: A longitudinal study

This study evaluated the breathing pattern of 30 obese patients [32 ± 9 years old; body mass index (BMI): 42.72 ± 4.10 kg/m(2)] before and after bariatric surgery and compared them with 30 control individuals (31 ± 8 years old, BMI: 21.99 ± 2.22 kg/m(2)). Measurements were performed using calibrated respiratory inductive plethysmography. Six months after bariatric surgery, obese patients exhibited a significant reduction in tidal volume (V(T)), minute ventilation (V(E)) and inspiratory duty cycle (T(I)/T(TOT)) compared with pre-surgical values. The control group had a higher breathing frequency, V(E) and phase angle (PhAng). There were no significant differences in V(T)/T(I), percentage of rib cage motion (%RC) or abdominal motion (%AB). Obese patients exhibited changes in their breathing pattern and asynchrony after bariatric surgery without any changes in thoracoabdominal motion. Certain aspects of the breathing pattern of obese patients became more similar to those of the controls after surgery.