SESSION TITLE: Pulmonary Rehabilitation Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM
PURPOSE: To find out an optimal breathing strategy, relationships between breathing pattern and dyspnea were studied using an experimental model to produce dyspnea.
METHODS: After the breathing at rest, inspiratory resistance of 0, 10, 20, and 30cmH2O/l/sec was loaded for a minute in ten normal male volunteers (age 21.6±1.9 yrs). Modified Borg scale (BS) was rated before and during the loading to record subjective dyspnea. Inspiratory capacity (IC) was measured immediately after the loading. These protocols were repeated four times. The first and second, the breathing pattern was not instructed at all. In the third and final, the subjects were advised to expire or to inspire deeply as possible. Between each protocol, the subjects took enough long intervals for their rests.
RESULTS: Minute ventilation (VE) and respiratory frequency (f) were not significantly changed during the loads. However, with resistance dependent fashion, mean inspiratory flow (VT/TI) decreased (p<0.05), duty cycle (TI/TTOT) and BS increased (p<0.05). During the deep expiratory protocol, BS was significantly lower (0cmH2O/l/sec 1.9±1.3 vs. 2.8±1.1, 10cmH2O/l/sec 2.3±1.0 vs. 3.0±1.2, 20cmH2O/l/sec 2.6±1.1 vs. 3.9±1.4, 30cmH2O/l/sec 3.2±1.3 vs. 4.0±1.4 p<0.05), and airway occlusion pressure (P0.1) was significantly higher (0cmH2O/l/sec 2.8±2.4 vs. 1.2±0.5, 10cmH2O/l/sec 5.1±3.3 vs. 2.5±1.2, 20cmH2O/l/sec 5.3±4.9 vs. 1.3±0.9, 30cmH2O/l/sec 5.3±4.3 vs. 2.1±1.2 p<0.05) than those during uninstructed breathing. Changes in the individual BS with expiration during any ventilatory loads were correlated with changes in the end-expiratory lung volume (EELV) values estimated from IC.
CONCLUSIONS: While the TI/TTOT showed little contribution to BS, VT/TI was closely associated with BS, suggesting little role of the timing of the respiratory cycle and a certain involvement of the tidal volume. Reduction of dyspnea during the inspiratory loading was associated with the increase in IC.
CLINICAL IMPLICATIONS: The breathing training to advise deep expiration may be useful and a key strategy for the breathing in patients with airflow limitation to alleviate dyspnea.
DISCLOSURE: The following authors have nothing to disclose: DAISUKE KOBAYASHI, Hajime Kurosawa, Hiromasa Ogawa, Toshiya Irokawa, Etsuhiro Nikkuni, Wataru Hida
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