What should an operator do immediately if a patient experiences adverse reactions during nitrous oxide administration?

In the event of adverse reactions during nitrous oxide administration, the most appropriate and immediate action is to remove the mask and administer oxygen. This response is crucial for several reasons.

First, nitrous oxide functions primarily as a sedative and analgesic agent, and while it is generally safe, some patients may experience side effects such as nausea, disorientation, or respiratory distress. When adverse reactions occur, it is essential to quickly alleviate the patient's exposure to nitrous oxide. By removing the mask, the operator stops the flow of the anesthetic gas, which can help prevent further reactions and provide immediate relief.

Next, administering oxygen helps counteract any potential hypoxia or decreased oxygen saturation that may result from the patient's adverse reactions. Providing supplemental oxygen supports the patient’s respiratory function, allowing them to recover more quickly and reducing the risk of serious complications.

In contrast, increasing the concentration of nitrous oxide is inappropriate, as it would likely exacerbate the adverse reactions. Applying pressure to the abdomen may be irrelevant to the patient's immediate respiratory needs, and waiting for the reactions to subside without intervention could endanger the patient’s safety and comfort. Therefore, the correct response focuses on promptly ceasing nitrous oxide exposure and ensuring adequate oxygenation.