Alternating low air loss pressure overlay for patient bedside chair and mobile wheel chair

An alternating pressure air sac overlay for therapeutic treatment of an immobile patient's skin while seated in a wheel chair, comprising:

• an array of elongated independently sealed air sacs constructed of an airtight material, sized in length to fit across a wheel chair, said individual air sacs being tubular in shape, mounted in a fixed side-by-side array, the overall longitudinal length of the air sac array being sized to fit at least on a seat of said wheel chair, a first group of independent air sacs being separated by a second group of air sacs in a side-by-side array, so that every other one of said air sacs in said first group and every other alternating one of said air sacs is contiguous with said first group to form said second group of air sacs;
• first conduit manifold connected to said first group of air sacs;
• second conduit manifold connected to said second group of air sacs;
• a battery powered air pump having an inlet and an outlet for providing pressurized air in fluid communication and connected to said first conduit manifold and said second conduit manifold;
• controllable air inlet valve means connected to said air pump and said first conduit manifold and said second conduit manifold, whereby in a first position, said air inlet valve means provides air pressure only to said first conduit manifold from said air pump, and in a second position, provides air under pressure only to said second conduit manifold from said air pump;
• means including timing circuits for controlling air in a timed sequence into said first conduit manifold and said second conduit manifold from said air pump connected to said air pump;
• an electrical battery power supply connected to said air pump, said electrical battery power supply having means for recharging;
• and
• said timing circuits connected to said electrical battery power supply and said means for controlling air in a timed sequence;
• a coverlet comprising a liquid impervious barrier means removably connectable to said air sac array, covering said air sac array to provide a protective shield against liquids reaching said air sac array, said coverlet porous to water vapor molecules, said coverlet including means for attachment to said wheel chair seat.