Which assessment finding for a client receiving oxygen therapy with a nonrebreather mask requires the nurse to intervene immediately?

A. This flow rate is within the normal range (10–15 L/min) for a nonrebreather mask, which is sufficient to maintain partial inflation of the reservoir bag and deliver high-concentration oxygen. B. This is normal function. The exhalation ports allow carbon dioxide to escape during exhalation while preventing rebreathing of exhaled air. C. This is expected and appropriate. Closing the exhalation ports during inhalation ensures the patient draws oxygen from the reservoir bag rather than room air. D. A collapsed bag indicates that the patient is not receiving adequate high-concentration oxygen, which can quickly lead to hypoxemia and respiratory compromise. Causes may include low oxygen flow, a loose mask, or tubing obstruction. Immediate intervention is required to check the oxygen source, ensure proper mask fit, inspect tubing for kinks or disconnections, and monitor oxygen saturation.