This study aims to evaluate the effect of supervised incentive spirometry (SIS) compared to unsupervised incentive spirometry (Non-SIS) on pulmonary function in patients following coronary artery bypass graft (CABG) surgery. Participants perform incentive spirometry exercises twice daily for three days after extubation. Pulmonary function parameters, including forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF), are assessed before and after the intervention period to compare changes between the two groups.