What should a therapist do if a nonrebreather mask reservoir collapses completely during heliox therapy?

In the context of heliox therapy, if the nonrebreather mask reservoir collapses completely, it indicates that the patient is not receiving an adequate supply of the heliox mixture. Increasing the flow rate to the mask is essential in this situation because it helps to ensure that the reservoir is adequately filled, allowing for effective delivery of the heliox to the patient. A well-inflated reservoir bag is crucial during heliox therapy, as it provides a sufficient volume of gas for the patient to inhale, which is especially important for managing conditions requiring high-flow oxygenation.

The other options, while they might be relevant in specific scenarios, do not directly address the immediate need to restore adequate gas flow to the patient. Changing to a nasal cannula would likely reduce the efficiency of gas delivery, notifying the physician may delay necessary intervention, and maintaining the current heliox mixture without addressing the collapsed reservoir would not ensure effective treatment. Therefore, increasing the flow rate is the most appropriate and immediate action to take in this situation.