This single-center randomized controlled trial will evaluate whether real-time visual feedback from electrical impedance tomography (EIT) improves the immediate distribution of lung ventilation during incentive spirometry in adults with postoperative atelectasis. Approximately 60 participants will be randomized 1:1 to receive either EIT-guided visual feedback or standardized verbal guidance during one session of 30 incentive-spirometry breaths. The primary outcome is the change in dorsal ventilation fraction from before training to 5 minutes after training. Secondary outcomes include inspiratory capacity, ventilation homogeneity, dependent silent spaces, end-expiratory lung impedance, oxygenation, in-hospital intubation or reintubation, and intervention-related adverse events.