Investigation of Dynamic Hyperinflation and Its Relationship With Functional Exercise Capacity in Children With Bronchiectasis

Exercise or hyperpnea-induced air trapping is referred to as dynamic hyperinflation. In the presence of high resistance to expiratory flows and short expiratory times, the respiratory system is unable to return to its resting volume at the end of exhalation. The positive pressure within regions of hyperinflated lung raises the mean intrathoracic pressure and causes the inspiratory muscles to operate at a higher than resting lung volume. Thus, dynamic hyperinflation places the respiratory muscles at a considerable mechanical disadvantage and further impairs respiratory function. Dynamic hyperinflation is considered to be a key determinant of exercise capacity in patients with obstructive lung diseases. Although bronchiectasis is one of the obstructive lung diseases, the presence of dynamic hyperinflation in these patients has not been adequately investigated. Management guidelines of bronchiectasis state that imaging methods or pulmonary function tests alone is not sufficient to determine the disease burden and prognosis in these patients, so they recommend including detailed evaluation of exercise tolerance in the management of bronchiectasis. Aim of this study is to investigate the prevalence of dynamic hyperinflation and its relationship with functional exercise capacity in children with bronchiectasis.