When selecting an alternating pressure bed, consider the following factors: 1. Patient Needs: Assess the patient's condition, weight, and risk of pressure ulcers to choose the right mattress specifications. 2. Adjustability: Look for beds with adjustable pressure settings to cater to varying patient needs. 3. Durability: Ensure that the mattress materials are durable and easy to clean. 4. Budget: Factor in the cost of the bed and any additional maintenance expenses.