GB2294635A - Inflatable mattress - Google Patents

Abstract

An inflatable mattress has an upper layer of inflatable tubular sections (10) covered with a microporous vapour permeable material (14) and a rectangular lower base layer (12) formed into a matrix of blocks with discrete, separate, support surfaces (22) by means of intersecting channels (18, 20). The mattress also has means (32) for inflating at least one of the inflatable sections (10) at a first, higher pressure and at least one of the inflatable sections at a second, lower pressure and means for changing the sections to which the higher and lower pressures are applied. As the higher pressure is applied to a section (10) the foam blocks (12) located immediately below that section are deformed downwardly without producing any substantial deformation of adjacent blocks and thus without moving adjacent tubular sections. <IMAGE>

Description

DESCRIPTION INFLATABLE MATTRESS The present invention relates to mattresses, and in particular, but not excLusively, to mattresses or the prevention of, and relief from, decubStus ulcers.

Decubitis ulcers occur when blood flow trough the skin capillaries is occluded by virtue of the act that tissue is compressed for a prolonged period by the weight of the person and a support surface. A person who is healthy responds to nervous signals fro the area of tissue in question when. the tissue has been compressed for some time, and the person will thus automatically shift position to relieve the compressed area, thereby enabling blood flow to recommence. This procedure repeats itself indefinitely.

However, people without the ability to move themselves, e.g. comotose, obtunded or severely disabled people, cannot relieve the pressure n this way, and thus if they are allowed to remain in tne same position, parts of the tissue die and become ulcerated, producing what are commonly termed pressure sores". The problem also arises with elderly people who have restricted movement. The problem is exacerbated by diet, immobility, possible low blood pressure/volume and poor skin perfusion.

The traditional way of preventing or relieving bed pressure sores ras been to turn the pat yen freauently, thus causing a different area of the patient to be compressed from time to time. However, this is nct aiways practical or possible.

A alternative way is to place the patient on an overlay, with a view to contacting more areas of the body in order to spread the patient's weight.

However, although such an overlay is comfortable, it frequently does not prevent or relieve pressure sores, since the pressure relief obtained in the areas most at risk (e.g. bony prominences) is very often insufficient to enable re-establishment of te blood flow.

A number cf prior art devices have attempted to overcome the aforementioned problems. However, the prior art devices Involve alternate inflation and deflation of a number of inflatable cells. Allowing cells to deflate causes problems in that a deflate eil provides no support at all, with the result tat it is possIble for a person, particularly a heavy person, to engage a supporting surface below the device in the region of a deflated cell, thus providing no pressure relief. On the other hand, it as been known for very light persons to slip trough the gap between two inflated cells in the region. cf a deflated cell, which can be most uncomfortable and unnerving.

The arrangement described in US 5243721 overcomes or alleviates all of the above problems and disadvantages. It is an object of the present invention to improve still further the arrangement described in US 5243721 and to reduce still further the likelihood of occurrence of the decubitus ulcers and to also speed the healing process.

In accordance with the present Invention an inflatable mattress having an upper layer of inflatable sections is provided with a deformable base beneath the inflatable cells, the base comprising a plurality of joined blocks each having a substantially flat upper surface, the flat upper surfaces of the joined blocks being spaced from one another.

In this way, as a section of the upper layer is inflated at a higher pressure the blocks of the base layer immediately below will deform without substantially deforming other blocks of the base, thereby reducing the height of the upper surface of the inflatable section.

The joined blocks are preferably aligned in a plurality of rows, each row, in use, being aligned with an inflatable section of the upper layer.

Preferably, the inflatable mattress further comprises inflation means which in use inflates at least one of the inflatable sections at a first, higher pressure and simultaneously inflates at least one of the inflatable sections at a second, lower pressure and which also has means for changing the sect Ion to which the hIgher and lower pressures are applied.

Preferably the blocks are formed from a single blcck of foamed material.

3y way of example only, specific embodiments of the present invent ' on will now be described with reference to the accompanying drawIngs, in which: Fig. 1 is a perspective view of a first embodiment of mattress in accordance with the present invention, shown with a cover partly cut away; Fig. 2 Is a transverse cross-section trough a portion cf the mattress of Fig. 1; Fig. 3 is a plan view of a portion of the base of te mattress of Fig. 2; and Fig. E is a transverse cross-section trough a second embodiment of mattress in accordance with the present nventon.

Referring firstly to Figs. 1 and 2, a rectangular mattress comprises a plurality of transverse elongate nflatable hollow tubular sections 10, each formed from flexible polyurethane sheeting which is radiofrequency welded into the desired shape and configuration. The sections are held in position such that they lie parallel to one another to form the mattress as illustrated, with the sect Ions 10 In use extending transversely to the iongitudsnal dIrection of a bed upon which it is to be located.

In use, the mattress is located swithin a removable flexible cover 14 whose upper and side walls are made from microporous vapour permeable material.

As seen in Figures 1 and 2, the inflatable sections 10 form an upper layer and rest on a lower rectangular base layer 12. The lower base layer 12 is of the same length and width as the upper layer and comprises a single piece of foamed material, such as polyurethane foam. As best seen in Flg. 3, the foamed material is formed into a regular array of square cells or blocks 16 by means of perpendicuìarly intersecting V-shaped channels 18, 20 which are aligned with the longitudinal and transverse directions respectively of the mattress. The blocs 12 are thus separated from each other by the channels 16,18 such that they are deformable substantially independently of one another but are formed trorn a single piece of foam such that the layer 12 is movable as an integral unit. The upper surface of each of the blocks 16 Is thus formed into a plurality of dIscrete support surfaces 22 formed by the upper flat surfaces of the blocks 16. The support surfaces are smooth and occupy the majority cf the available upper surface of ne base 12.

Beneath each inflatable section 10 of the upper layer is located a row of blocks 12 (and thus a row cf support surfaces 22) aligned with the transverse dIrection of the mattress. As the higher pressure is applied to one of the Inflatable sections 10 the blocs 12 n the row located immediately below that section are deformed downwardly thus helping to keep he level of the upper surface of the mattress as constant as possible.

The upper layer 10 of the mattress is substantially as described in United States Patent 523721, but will be briefly described below.

One end of each of the tubular sections 18 is provided wit a T-ccnnector 26 which communicates with.

the interior of the sections. Groups of inflatable sect ions are formed from sequentially arranged sections 10a, 10b, 1Cc such that every third section -s part of the same group and is connected to adjacent sections of that group by means of flexible tubing 2Ba, 28b, 28c respectively, extending between te relevant T-connectors 26. The three sections 10 adjacent to one end of the mattress are supplied wlth pressurised air from a pump unit 32 by means of which respective flexible tubing 30 which passes through apertures (not shown) in the side of the cover.The pump unit is adapted to control the pressure in the three groups of inflatable sections 10, such that the pressure is either a first, higher pressure or a second, lower (but non-zero) pressure, the pressure applied to each group of sections changing at predetermined times.

When a higher pressure is connected to one group of sections (e.g. section 10a in Fig. 2) each of the sections 10a expands while the lower pressure n the adjacent section 10b causes the section 10b to partially deflate. However, the increased pressure in section 10a causes the blocks 14 of the lower layer i2 in the row aligned immediately below in the base layer to be deformed downwardly. Since the blocks are divided by means of the channels 16, 18, deformation of one block has little or no effect on otter blocks of the base.

Thus, as the higher pressure is applied to one of the inflatable sections, the foam blocks 12 located immediately below that inflatable section are deformed downwardly without producing any substantial deformation of the foam blocks in any other rows.

Thus, the upper surface of the inflatable section 10a to which the higher pressure is applied is lower than it would have bee without the base layer 12.

This arrangement tends to even out the undulations of the mattress and provide a larger useful surface area which can contact the patient, thereby reducing the likelihood of high-pressure spots. if a low resilience foam, such as TEMPUR (Trade Mark) is used to form the base 10, then greater compression occurs, thus further reducing the height of the upper surface of the Inflated section located above.

As seen in Eig. 4, the base may comprise a combination of foams. Fig. 4 shows a base having an integral base portion 12' made from a relatively high resilience polyurethane foam and an array of blocks 16', adhered to te upper surface of the base portion 12' and made from low resilience TEMPUR foam. Other combinations of foams are possible.

Claims (17)

1. An inflatable mattress comprising an upper layer having a plurality of inflatable sections and a deformable base beneath the inflatable sections, the base comprising a plurality of discrete support surfaces separated from one another.

2. A mattress as claimed in claim i, wherein the support surfaces are substantially smooth.

3. A mattress as claimed in claim 2, wherein tne smooth surfaces are substantially planar.

4. A mattress as claimed in claim 1 or 2, wherein the support surfaces are formed in a plurality of rows.

5. A mattress as claimed in claim 4, wherein each row is aligned with an inflatable section of the upper layer.

6. A mattress as claimed in any of the preceding claims, wherein the support surfaces occupy a majority of the available surface area of the base.

7. A mattress as claimed in any of the preceding claims, wherein the base comprises a plurality of joined blocks whose upper surfaces are spaced from one another to form the support surfaces.

8. A mattress as claimed in claim 7, wherein the blocks are substantially identical.

9. A mattress as claimed in any of the preceding claims, wherein the base is resiliently deformable.

6. A mattress as claimed in any of the preceding claims, wherein the base comprises foamed plastics such as polyure=hane foam.

11. A mattress as claimed In claim 10, where te foam comprises a low or zero-resilience foam such as TEMPUR (Trade Mark).

12. A mattress as claimed in claim 10 or 11, wherein the base comprises two or more different tyres of foamed plastics.

13. A mattress as claimed in any of the preceding claims, wherein the base is formed as an integral unit.

14. A mattress as claimed in any of the preceding claims, wherein the support surfaces are defined by intersecting channels formed in a surface of the base layer.

15. A mattress as claimed in any of the preceding claims, wherein the upper layer comprises a plurality of transversely extending elongate inflatable sections.

16. A mattress as claimed in any of the preceding claims, further comprising inflation means which in use inflates at least one of the infiatable sections at a first, higher pressure and simultaneously Inflates at least one of the inflatable sections at a second, lower pressure, and having means for changing the section to which the higher and lower pressures are applied.

17. An inflatable mattress substantially as herein described, with reference to, and as illustrated in, the accompanying drawings.