Relationship between pulmonary hyperinflation and dyspnoea severity during acute exacerbations of cystic fibrosis

Background and objectiveAcute exacerbations of cystic fibrosis (CF) occur frequently throughout the course of the disease. Dyspnoea is the most common and distressing symptom experienced by patients during these episodes. We tested the hypothesis that pulmonary hyperinflation is an important determinant of dyspnoea severity during acute exacerbations. MethodsWe studied patients during an acute exacerbation of CF. Lung volumes, spirometry and dyspnoea scores were measured at Day 0, Day 7, at the end of treatment (EOT) and 14days following the EOT. ResultsAt the start of treatment, mean residual volume (RV)/total lung capacity (TLC) was 54.9%, which decreased significantly with treatment, as did vital capacity (VC), inspiratory capacity (IC) and dyspnoea scores. IC was the only independent predictor of dyspnoea severity. ConclusionOur study demonstrates significant improvements in hyperinflation, spirometry and dyspnoea scores with treatment of acute exacerbations of CF. Hyperinflation, rather than airflow limitation, may contribute towards the increased dyspnoea during exacerbations. This study explores the relationship between dyspnoea and pulmonary function during acute exacerbations of cystic fibrosis (CF). Indicators of pulmonary hyperinflation, rather than forced expiratory volume in 1s (FEV1 ), are associated with the severity of dyspnoea during treatment. As total lung capacity (TLC) does not change with treatment, inspiratory capacity (IC) measurement may provide a useful means of assessing treatment response.