Explanation:

When a nurse detects a hematoma at the IV catheter insertion site, applying warm compresses is beneficial as it can promote healing by enhancing circulation and reducing swelling. Elevating the client's arm helps in reducing edema, which can relieve pressure, pain, and further bleeding in the hematoma area. Stopping the infusion may be necessary in certain situations, but it is not a standard action for all hematoma cases. Applying alcohol to the insertion site is discouraged as it can cause irritation and may not aid in resolving the hematoma.