What should be done prior to applying a nonrebreather mask?

Before applying a nonrebreather mask, inflating the oxygen reservoir prior to its application is crucial for ensuring the mask functions effectively. The nonrebreather mask is designed to deliver a high concentration of oxygen to the patient, and the reservoir bag needs to be filled with oxygen so that the patient can access this high concentration during inhalation. By pre-inflating the reservoir, you create a supply of oxygen that is readily available when the mask is placed on the patient, which is vital in situations where the patient is experiencing respiratory distress or requires supplemental oxygen.

This practice enhances the effectiveness of the mask in delivering a higher percentage of oxygen (around 90% or more), which is essential for patients with significant hypoxia. It also helps prevent the risk of the reservoir collapsing during inhalation—this would otherwise reduce the amount of oxygen the patient receives.

Other actions such as checking vital signs or ensuring the reservoir is deflated are important in their own contexts but do not relate directly to the immediate preparation of the mask for effective oxygen delivery. Turning off the oxygen oxygen temporarily would counteract the objective of using the nonrebreather mask, which is to provide a continuous supply of oxygen.