An older client recently transferred to a rehabilitation facility after aortic valve replacement surgery is experiencing anxiety and difficulty adjusting to the transition. The healthcare provider prescribes an antidepressant and a mild sedative for sleep. Which intervention is most important for the nurse to include in the client's plan of care?

A. Measure and record the client's urinary output every day. While monitoring urinary output is important, it is not as directly related to the safety concerns associated with the new medications and the client's current state. B. Obtain a blood pressure reading before the client gets out of bed. This is the correct answer because both antidepressants and sedatives can cause orthostatic hypotension, which could lead to falls or other complications. Monitoring blood pressure before the client gets up helps to prevent these issues. C. Obtain the client's vital signs every 4 hours when awake. Regular vital sign monitoring is important, but specific attention to orthostatic changes is more critical in this scenario. D. Provide the client with teaching regarding a cardiac diet. While dietary education is important for long-term health management, it does not address the immediate risk associated with the prescribed medications and potential orthostatic hypotension.