Water filled pressure relief device with rectangular aperture

Claim 1

A pressure relief device comprising a parallelepiped hollow cushion of flexible plastic material having a parallelepiped central aperture therethrough, valve means extending through said device for filling said device for water, gripping means integrally formed with said device to facilitate shifting of the device relative to a patient, and means located in said device to prevent the growth of bacteria and to provide a tracer dye, said cushion being comprised of an upper rectangular sheet having a rectangular aperture in the center thereof, a lower rectangular sheet having a rectangular aperture in the center thereof, an outer peripheral strip sealed between the outer edges of said upper sheet and said lower sheet to define an outer side wall and an inner peripheral strip connected between the edges of said apertures in said upper and lower sheets to define an inner side wall wherein the edges of said strips and the edges of said upper sheet are folded inwardly in overlapping relation to define an outwardly smooth strong waterproof seal and the edges of said strips are sealed to the bottom sheet in flat overlying relation thereto whereby the cushion, when filled with water, will tend to maintain the edges of the upper sheet in spaced relation to the edges of the lower sheet upon the application of pressure to the upper sheet between the outer edges and the edges of the aperture to maintain the bony protuberances of a patient which are aligned with the aperture in spaced relation to whatever surface the cushion is placed upon, said gripping means being defined by a plurality of lateral extensions provided on said lower sheet in folded back relation and sealed between the lower edges of said outer peripheral strip and said lower sheet, providing at least one loop on each side of said cushion, thus providing gripping means for positioning said device relative to the bony protuberances of a patient.