A nurse is caring for a client who is using a non-rebreather mask for oxygen delivery. The nurse should identify which of the following as an indication that the equipment is functioning properly?

A. Air is heard escaping from around the mask: Escaping air indicates a poor seal, which compromises the delivery of high-concentration oxygen. A properly functioning non-rebreather mask should have a snug fit to the face, minimizing leaks and ensuring the client receives the intended oxygen concentration. B. The flow control meter dial is at the correct setting: While setting the prescribed flow rate is necessary, the flow meter alone does not confirm that the mask or reservoir is functioning properly. The actual delivery of oxygen to the client depends on correct assembly, reservoir inflation, and mask seal. C. The attached reservoir bag is inflated: An inflated reservoir bag indicates that oxygen is flowing into the bag and that the client will receive near 100% oxygen during inspiration. Proper inflation confirms that the one-way valves are functioning and that the mask is delivering high-concentration oxygen as intended. D. The exhalation ports are covered during inspiration and expiration: Exhalation ports on a non-rebreather mask should remain open to allow carbon dioxide to escape while one-way valves prevent room air from entering during inspiration. Covered ports would restrict gas exchange and compromise oxygen delivery, indicating malfunction.