Short-Term Effects of Elastic Chest Wall Restriction on Pulmonary Function in Children with Cystic Fibrosis.

ABSTRACT

BACKGROUND: Elastic chest wall restriction introduced by Chevaillier is thought to reduce existing hyperinflation and improve mucus clearance from peripheral airways. In healthy adults, restriction decreases the functional residual capacity (FRC) and forced vital capacity (FVC), while ventilation inhomogeneity (lung clearance index [LCI]) increases. Pulmonary function response to restriction is unknown in individuals with cystic fibrosis (CF). OBJECTIVES: To examine short-term effects of elastic chest wall restriction on pulmonary function in children with CF. METHODS: Pulmonary function was first assessed twice 15 min apart at baseline and then again following 15 min of elastic chest wall restriction in 20 school-aged children with CF (12.3 ± 3.4 years). Primary outcomes were LCI from nitrogen multiple-breath washout, residual volume (RV), and FRC from plethysmography. Secondary outcomes were FVC and end-expiratory lung impedance (EELI) from electrical impedance tomography. Endpoints were test-retest reliability at baseline and lung function response to restriction, both on group and individual levels. RESULTS: Test-retest reliability was excellent (intra-class correlation coefficients range 0.84-0.99). Following restriction, FRC significantly declined on average (95% CI) by -0.09 (-0.17 to -0.02) L. Similarly, FVC declined while LCI did not change. RV and EELI declined, but this did not reach statistical significance. On the individuals' level, heterogeneous changes in pulmonary function occurred following elastic chest wall restriction. CONCLUSIONS: These findings indicate that the application of elastic chest wall restriction is safe, induces the intended decline in resting lung volume but does not systematically alter ventilation inhomogeneity in children with CF.