Which complication is most associated with a 90-year-old patient after surgery?

• A. Atelectasis
• B. Delirium
• C. Pneumonia.
• D. Thrombosis

Answer: (C)

In very elderly patients after surgery, the risk of developing a lung infection rises because aging changes how the lungs and immune system respond to anesthesia, pain, and immobility. Reduced chest wall compliance and weakened respiratory muscles make shallow breaths more likely, and the cough reflex plus mucociliary clearance slow down. Pain and bed rest promote shallow breathing and retention of secretions, creating an environment where bacteria can thrive and pneumonia can develop. This makes pneumonia the most likely pulmonary complication in a 90-year-old after surgery.

Atelectasis is a common early pulmonary change due to shallow breathing, but it often improves with incentive breathing and mobilization and does not necessarily represent an established infection. Delirium is a frequent neurocognitive issue in elderly postoperative patients, not a lung infection. Thrombosis is a vascular complication related to immobility and clotting risks, not a lung infection.