Systems, methods, and apparatus are provided for preventing and treating pressure ulcers in bedfast patients. The invention includes monitoring a bedfast patient using a sensor array disposed between a patient and a support surface, the sensor array adapted to transmit signals indicative of interfacial pressure and blood oxygen saturation levels; and a processor coupled to the sensor array and adapted to receive the signals from the sensor array to determine if an undesirable condition exists. Numerous additional aspects are disclosed.