The Short-Term Effect of Breathing Tasks Via an Incentive Spirometer on Lung Function Compared With Autogenic Drainage in Subjects With Cystic Fibrosis

Abstract

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.