A patient with a hemoglobin of 7.8 g/dL is planning ambulation after knee arthroplasty. What is the most appropriate activity level?

• A. No physical activity
• B. Slow ambulation
• C. Low-level resistive exercises
• D. There is no restriction to physical activity

Answer: (A)

The key concept is that low hemoglobin limits the body's ability to deliver oxygen to working muscles during activity. With a hemoglobin around 7.8 g/dL, oxygen delivery is markedly reduced, so even light exertion can provoke fatigue, tachycardia, dizziness, or chest symptoms in a postoperative patient. In the knee replacement rehab setting, safety takes priority when anemia is that pronounced: ambulation or any physical activity that increases oxygen demand could provoke hemodynamic stress. Therefore the most appropriate approach at this level is to avoid physical activity and defer ambulation and more exertional therapy until the hemoglobin is corrected or the patient is cleared by the physician. Monitor for symptoms and reassess as hemoglobin improves or treatment is instituted.