a waterproof plastic or rubber pad that can be applied to areas of muscle sprain, edema, or mild inflammation. The pad contains channels through which heated or cooled water flows. The device is connected by hoses to a bedside control unit that contains a temperature regulator, a motor for circulating the water, and a reservoir of distilled water. Although generally safer than a conventional heating pad, the aquathermia pad should be checked periodically to avoid the risk of accidental burns. Also called water flow pad.