The short-term effect of breathing tasks via an incentive spirometer on lung function compared with autogenic drainage in subjects with cystic fibrosis

BACKGROUND: Forced expiration may assist secretion movement by manipulating airway dynamics in patients with cystic fibrosis (CF). Expiratory resistive breathing via a handheld incentive spirometer has the potential to control the expiratory flow via chosen resistances (1- 8 mm) and thereby mobilize secretions and improve lung function. Our objective was to explore the short-term effect of using a resistive-breathing incentive spirometer on lung function in subjects with CF compared with the autogenic drainage technique. METHODS: This was a retrospective study. Subjects with CF performed 30 - 45 min of either the resistive-breathing incentive spirometer (n 40) or autogenic drainage (n 32) technique on separate days. The spirometer encourages the patient to exhale as long as possible while maintaining a low lung volume. The autogenic drainage technique includes repetitive inspiratory and expiratory maneuvers at various tidal breathing magnitudes while exhalation is performed in a sighing manner. Spirometry was performed before and 20 -30 min after the therapy. RESULTS: Use of a resistive-breathing incentive spirometer improved FVC and FEV1 by 5- 42% in 26 subjects. The forced expiratory flow during the middle half of the FVC maneuver (FEF_25-75%) improved by >20% in 9 (22%) subjects. FVC improved the most in subjects with an FEV1 of 40 - 60% of predicted. Improvements negatively correlated with baseline percent-of-predicted FVC values provided improvements were above 10% (r² 0.28). Values improved in a single subjects using the autogenic drainage technique. CONCLUSIONS: These 2 techniques may allow lower thoracic pressures and assist in the prevention of central airway collapse. The resistive-breathing incentive spirometer is a self-administered simple method that may aid airway clearance and has the potential to improve lung function as measured by FVC, FEV₁, and FEF_25-75% in patients with CF.