Abstract: A sensor for an inflatable cushion, the sensor including a base with a conductive area in an appropriate configuration relative to the area of the patient's anatomy positioned on the cushion. The conductive area of the base can be optimally configured to correspond to the bony prominences of the buttocks or ischia position on an air cell cushion. There are electrodes connected to the conductive area that generate an electromagnetic field of a predetermined configuration. A disturbance of the electromagnetic field created by a change in position of the patient is transmitted to an indicator so that an observer can determine if the patient is appropriately immersed in the cushion.