Lobectomy patients frequently experience postoperative respiratory complications such as secretion retention, dyspnea, impaired gas exchange, and reduced lung function, which can delay recovery. Oscillatory Positive Expiratory Pressure (OPEP) devices such as Acapella and Flutter are commonly used to improve airway clearance and pulmonary function. This study aims to compare the effects of Acapella and Flutter devices on secretion clearance, dyspnea, arterial blood gases, and lung function in post-lobectomy patients.