What is the priority nursing measure for a client with von Willebrand's disease experiencing epistaxis?

Applying pressure to the nose is the priority nursing measure for a client with von Willebrand's disease experiencing epistaxis. This technique is critical because it helps to control bleeding by promoting clot formation at the site of the bleeding. Applying direct pressure effectively reduces blood flow, thus minimizing the amount of blood lost during an epistaxis episode. This is particularly important for clients with von Willebrand's disease, as they have a bleeding disorder that affects the blood’s ability to clot effectively.

In the context of managing a nosebleed, other interventions may provide support but are not as immediately effective. Laying the client supine can potentially increase blood flow to the head, which may exacerbate bleeding rather than help control it. Avoiding packing the nostrils is not a priority since gentle packing can sometimes be necessary to halt bleeding. Applying a warm cloth to the bridge of the nose does not contribute directly to stopping the bleeding and may, in fact, be counterproductive if the warmth prompts more blood flow to the area. Therefore, applying pressure to the nose is the most appropriate and effective first response to manage the situation effectively.