RESUMO
PURPOSE: Breathing pattern retraining is frequently used for exertional dyspnea relief in adults with moderate to severe chronic obstructive pulmonary disease. However, there is contradictory evidence to support its use. The study objective was to compare 2 programs of prolonging expiratory time (pursed-lips breathing and expiratory muscle training) on dyspnea and functional performance. METHODS: A randomized, controlled design was used for the pilot study. Subjects recruited from the outpatient pulmonary clinic of a university-affiliated Veteran Affairs healthcare center were randomized to: 1) pursed-lips breathing, 2) expiratory muscle training, or 3) control. Changes over time in dyspnea [modified Borg after 6-minute walk distance (6MWD) and Shortness of Breath Questionnaire] and functional performance (Human Activity Profile and physical function scale of Short Form 36-item Health Survey) were assessed with a multilevel modeling procedure. Weekly laboratory visits for training were accompanied by structured verbal, written, and audiovisual instruction. RESULTS: Forty subjects with chronic obstructive pulmonary disease [age = 65 +/- 9 (mean +/- standard deviation) years, forced expiratory volume 1 second/forced vital capacity % = 46 +/- 10, forced expiratory volume 1 second % predicted = 39 +/- 13, body mass index = 26 +/- 6 kg/m, inspiratory muscle strength = 69 +/- 22 cm H2O, and expiratory muscle strength (PEmax) = 102 +/- 29 cm H2O] were enrolled. No significant Group x Time difference was present for PEmax (P = .93). Significant reductions for the modified Borg scale after 6MWD (P = .05) and physical function (P = .02) from baseline to 12 weeks were only present for pursed-lips breathing. CONCLUSION: Pursed-lips breathing provided sustained improvement in exertional dyspnea and physical function.
