Which inspection finding likely indicates atelectasis in a postoperative adult client?

Atelectasis is the collapse of alveoli or a lung segment, most commonly occurring postoperatively due to shallow breathing, retained secretions, or splinting from pain. When a lung segment collapses, the surrounding musculature must generate greater negative pressure to attempt inflation of the affected area, producing visible intercostal retractions on the affected side during inspiration. This asymmetric effort reflects the mechanical disadvantage created by the collapsed lung tissue. A barrel-shaped chest with a widened costal angle is characteristic of long-standing chronic obstructive pulmonary disease due to air trapping, not acute atelectasis. Cyanosis of lips and nailbeds is a late and nonspecific sign of hypoxemia that can occur with many respiratory disorders and is not specific to atelectasis on inspection alone. Bilaterally symmetric chest movement with quiet respirations describes normal, healthy respiratory mechanics and would actually be absent or diminished on the affected side in atelectasis. The hallmark inspection finding specific to atelectasis is reduced or absent chest expansion on the involved side, accompanied by the accessory muscle and intercostal retraction effort as the client tries to ventilate the collapsed region. Nurses caring for postoperative clients should monitor for this finding and encourage incentive spirometry and deep breathing to prevent or treat atelectasis.