Acapella Versus Lung Flute in Treatment of COPD Patients the Study Aims to Identify the Preference Between the Two Devices According to Treatment of COPD Patients Regarding Pulmonary Function Tests , Exercise Tolerence and Quality of Life Questionnaire,

is an airway clearance device that combines the resistive features of a positive expiratory pressure device with oscillations, which diminishes the mucus adhesiveness and decrease the collapsibility of airways

is a new oscillatory positive expiratory pressure (OPEP) device that produces a low frequency acoustic wave with vigorous exhalation that increases mucociliary clearance