The first step in the delivery of high-flow oxygen via a nonrebreather mask is to:

The delivery of high-flow oxygen via a nonrebreather mask begins with selecting the correct size mask for the patient. This step is crucial because a properly fitted mask will ensure an adequate seal against the patient’s face, which maximizes the effectiveness of oxygen delivery. If the mask is too large or too small, it may not fit securely, potentially allowing ambient air to dilute the oxygen concentration being inhaled by the patient. Proper sizing ensures that the mask functions as intended, providing high-flow oxygen efficiently.

While other steps like turning on the oxygen source, regulating the flow, and inflating the reservoir bag are all important in the process of administering oxygen, these actions are contingent upon first having the correct mask in place. Having the right fit allows the subsequent steps to be effective, ensuring optimal respiratory support for the patient in need of supplemental oxygen.