Final answer:
The most beneficial question for the nurse to ask the 76-year-old client with heart failure, sudden weight gain, and orthopnea would be: 'Have you been adhering to your medication and dietary regimen?' This question is important to assess whether the client needs medication adjustment or additional interventions.
Step-by-step explanation:
The most beneficial question for the nurse to ask the 76-year-old client with heart failure, sudden weight gain, and orthopnea would be:
'Have you been adhering to your medication and dietary regimen?'
This question is important because sudden weight gain and orthopnea in a client with heart failure can indicate fluid retention, which may be caused by noncompliance with medication and dietary restrictions. By asking about adherence to the prescribed regimen, the nurse can assess whether the client needs medication adjustment or additional interventions.