Bed pads have been used in the past to improve the comfort of patients immobilized for long periods of time. A so-called sheepskin pad has been used as well as foam pads, both smooth and convoluted. However, patients lying on such pads for long periods of time are still quite uncomfortable and very frequently acquire skin rashes and bed sores.
One object of this invention is to provide a bed pad of substantially improved comfort.
Another object of this invention is to provide a bed pad which will substantially decrease the incidence of skin rashes and bed sores.
Other objects and advantages of this invention will be apparent from the description and claims which follow taken together with the appended drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a plan view of an embodiment of this invention, with partial cutaway.
FIG. 2 is a section along line 2--2 of FIG. 1 showing the inflated condition.
FIG. 3 is similar to FIG. 2 except that it shows the deflated condition.
FIG. 4 is a plan view of another embodiment of this invention with partial cutaway.
FIG. 5 is a section along line 5--5 of FIG. 4 showing one tubular member 145 inflated and the other 245 deflated.
FIG. 6 is a partial longitudinal section of the inlet end of the support member of FIG. 4.
SUMMARY OF INVENTION
The bed pad of the present invention comprises generally a flexible, resilient, porous sheet supported by a pad-like structure including means for passing a current of air through resilient materials having an interconnected cell structure.
The support structure has large air-spaces and can comprise, for example, a length of flexible, plastic tubular member having openings on its top surface and arranged in a convoluted or branched form beneath the porous sheet. One end of the tube is closed, while the other end is connected to a small air compressor or the like. The support structure and porous sheet may be formed as separate pieces which can be permanently or temporarily attached to one another. It is generally preferable to have the porous sheet removable so that it may be exchanged or cleaned. A variable air supply is used providing a wide variety of different comfort positions.
The bed pad of this invention provides an air current at the interface between the patient and the porous pad, resulting in a flexible, comfortable support which prevents skin rashes and bed sores.
The air passes through to the outer surface of the sheet. As the air current varies variable flexing motion of portions of the sheet results.
In one form of the invention the tubular member alternately inflates and deflates, with interlaced, resilient strips providing a floor on deflation. In another form, two interlaced tubular members are used which alternately inflate and deflate. In both cases deflation occurs solely by the passage of air from said perforated tubular member, most of said air escaping through said porous pad. The branches are preferably transversely oriented with respect to the pad and thus with respect to the patient, in order to provide the optimum support and skin massaging action.
SPECIFIC EXAMPLES OF INVENTION
In the example illustrated in FIGS. 1, 2 and 3, two sheets of relatively thin plastic such as vinyl plastic, 43 and 44, are vacuum-formed and heat sealed so as to form a continuous closed, branched collapsible tube structure 4 having perforations 46, as well as a plurality of discrete, elongated pockets 48 of smaller diameter than the convoluted tube 45 in its inflated condition.
Prior to joining the molded sheets 43 and 44 by heat sealing, or other similar techniques, strips of relatively heavier walled non-perforated flexible tubing 49 are put into the pockets from which the sealed strips 48 are to be formed. An air supply conduit 47 is provided at the side. The resulting support structure is sealed at its edges so that air coming in through inlet 47 will pass into the convoluted portions but can escape only through air holes 46.
This embodiment is intended to be used with a variable air supply such as a small compressor. When the air is moving in, the tubular section 45 is inflated. It is preferably used in combination with base foam sheet 42 which is somewhat thinner than upper open foam sheet 41. When the air is not passing into the structure, tubular section 45 collapses so that the upper foam sheet 41 is effectively being supported by the plurality of flexible but self-supporting spaced strips 49.
It is noted that in its inflated condition the thin tubular structure 45 is constantly higher than the tubular sections 49, but that upon being deflated collapses to or below the height of section 49.
In the embodiment illustrated in FIGS. 4, 5 and 6, upper open foam sheet 41 overlays two sheets of relatively thin plastic such as vinyl plastic, 100 and 101 heat sealed to form closed interlaced, inflatable, perforated tubular members 145 and 245 having respectively closed branches 145a and 245a and singe air supply connections 147 and 247. The sheet 101 forms the upper walls 143 and 243 while sheet 102 forms the lower walls 144 and 244 of the two interlaced tubular members. Upper walls 143 and 243 have perforations 146 and 246 permitting air to escape from the tubular members and through the foam sheet 41. The structure rests on base foam sheet 42.
The air supplies to inlets 147 and 247 are so regulated as to alternate between the two tubular members, thus providing alternate inflation and deflation. When air is shut off from one tubular member, it loses its air and collapses.
I have found that the combination of variable air supply together with an inflatable and deflatable support provides a much higher degree of comfort and freedom from skin disease for the patient than has hitherto been feasible. With rapid inflation e.g., 1 1/2 to 3 seconds from a high volume air source, e.g., 1 to 1 1/2 cubic feet/minute, the patients comfort is further enchanced by a messaging action. Generally, the inflation period, the period during which air enters the tube, should not exceed 1 minute and is preferably 30 seconds or less.
Although it is not intended that this invention be limited in any way to particular dimension, I have found that a useful pad in accordance with this invention can be made with a length of about 3 to 7 feet and a width of about 1 1/2 to 3 feet. The collapsible, perforated tubes can have a wall thickness of about 0.020 inches. The upper foam sheet can be a thickness of the order of magnitude of 1/2 to 1 1/2 inches while the supporting structure can be of the order of magnitude of 1 inch and the bottom sheet about 1/4 inch in thickness. Both upper and lower sheets preferably extend beyond the extremities of the support structure.
One method of providing a variable air supply comprises the use of an air compressor and receiving tank, wherein an unloader valve opens when the tank pressure reaches a predetermined level, e.g., 28 p.s.i. and closes when the tank pressure falls to a second predetermined level, e.g., 8 p.s.i. The volume of air released from the tank during this interval inflates one porous tubular member and also passes from the air-holes through the foam sheet 41. When the interval is over, the remaining air bleeds out through air-holes until it is deflated; this, of course, being aided by the weight of the patient's body. The valve cycle and the porosity of the tubular members and sheet 41 can, of course, be in accordance with the desires of the doctor or patient.
In another method, a steadily operating air compressor is used with a slowly rotating distributor valve which can give a variety of cycles to one or more pads e.g., inflate tube for 15 seconds, no air for 15 seconds, inflate second tube for 15 seconds, no air for 15 seconds; or rotate first tube 30 seconds, inflate second tube 30 seconds, etc.