Patient support systems and, more particularly, patient support systems designed to reduce the risk of developing pressure sores by a patient are disclosed. A control unit is provided that operates a pump for setting and maintaining the inflation of the patient support system. The control unit is configured to receive a weight of a patient (either automatically from an integrated weighing device or as input by a caregiver) using the patient support system. The control unit then operates the pump to fill and maintain the patient support system to a predetermined pressure based upon an electronically stored pressure versus weight model accessible to the control unit, where the pressure versus weight model is set to avoid bottom-out and overpressure conditions for the patient having the weight.
