A nurse is assisting with the care of a client who has a closed-chest tube drainage system. Which of the following actions should the nurse take?

Closed-chest tube systems manage pleural fluid or air, requiring patency and safety. Replacing the unit when the drainage chamber is full maintains system function overflow risks backpressure or infection, per manufacturer guidelines. Monitoring for 150 mL/hr is excessive; normal drainage tapers post-insertion, and sudden high output signals bleeding, not a routine action. Clamping the tube risks tension pneumothorax by trapping air or fluid, only done briefly under specific orders (e.g., checking for leaks). Pinning tubing to sheets prevents dislodgement but isn't the primary maintenance action. Full chamber replacement ensures continuous drainage, aligns with infection control (e.g., CDC standards), and prevents complications like lung collapse, making it the nurse's key responsibility in chest tube care.