Final answer:
Post-mastectomy care includes elevating the right arm on a pillow to prevent swelling, and encouraging gentle range of motion exercises as part of a progressive physical therapy plan. Sleeping on the operated side is not recommended for comfort or healing.
Step-by-step explanation:
A nurse planning care for a client who is having a modified radical mastectomy of the right breast should include a variety of interventions to ensure proper recovery. One important intervention is to elevate the right arm on a pillow to prevent lymphedema and to promote drainage from the surgical site. Encouraging gentle range of motion exercises for the affected arm is also important; however, these should be active-assistive rather than active exercises early on to avoid straining the surgical site. This is part of the appropriate physical therapy plan that progresses in phases after a thorough evaluation by a physical therapist to enhance healing and restore function. Instructing the client to sleep on the operated side is not advisable since it may cause discomfort and impair the healing process.