The SpO2 of a client receiving oxygen therapy by nasal cannula at 6 L/min has dropped from 94% an hour ago to 90%. Which action does the nurse perform first to improve gas exchange before reporting the change to the primary health care provider?

A. While properly securing the cannula is important for comfort and consistent oxygen delivery, it is unlikely to be the primary cause of a significant drop in SpO2 unless the cannula is completely dislodged. B. Immediately increasing the flow rate without assessing the equipment or patient may be premature. The drop in SpO2 could be caused by mechanical issues or patient factors that need to be addressed first. Additionally, flow rates above 6 L/min are generally not recommended for standard nasal cannula because they can cause mucosal dryness and discomfort. C. The first action is to ensure the oxygen delivery system is functioning properly, as tubing obstruction, disconnection, or leaks are common, reversible causes of hypoxemia. Correcting these issues can immediately improve oxygenation before escalating care or altering prescriptions. D. Humidification improves comfort and prevents mucosal dryness, but it does not immediately affect oxygen saturation. Ensuring proper tubing function takes priority.