Layered material for acute pressure care (APC) mattress

Abstract

A flexible layered material comprises an outer skin; a first flexible fabric layer having a thickness of about 6mm to about 10mm; and a second flexible fabric layer having a thickness of about 17mm to about 22mm; wherein, in use, the outer skin is capable of facing a patient; the first fabric layer is positioned between the outer skin and the second fabric layer and comprises a plurality of first densely packed substantially parallel fibrous ribs between a first sheet proximate to the outer skin and a second sheet distant to the outer skin; and the second fabric layer comprises a plurality of second densely packed substantially parallel fibrous ribs between a third sheet proximate to the first fabric layer and a fourth sheet distant to the first fabric layer. The material is for use in an acute or hospital care setting to reduce the occurrence of pressure ulcers caused either by skin shearing or the breaking down of tissue through a lack of peripheral blood flow in patients required to spend time in a reclined or sitting position.

Description

[0001] Layered Material for Acute Pressure Care (APC) Mattress

[0002] The present invention relates to a layered material for an acute pressure care (APC) mattress or cushion. The layered material has particular application in acute / hospital care. The material is for use in an acute or hospital care setting to reduce the occurrence of pressure ulcers caused either by skin shearing or the breaking down of tissue through a lack of peripheral blood flow in patients required to spend time in a reclined or sitting position.

[0003] Background of the Invention

[0004] When treating patients having a variety of medical conditions in a hospital setting it is often necessary for the patient to spend time in a reclined or sitting position.

[0005] The World Health Organisation has reported that a high proportion of people leaving hospital after treatment return home with a pressure ulcer caused either by skin shearing or the breaking down of tissue through a lack of peripheral blood flow.

[0006] The materials used in known mattresses have attempted to address this problem, but there remains a need to find a solution which looks at both pressure sore management and skin shearing whilst patients are in both the laying supine position and also whilst sitting up in bed which causes more pressure and shearing in particular under the ischial tuberosities.

[0007] Looking at the medical equipment already on the open market, none appears to have addressed the problems of both skin shear and pressure care at the same time. Foam, gel and air products including air mesh, sand beds and indeed water beds all take into account pressure care management along with comfort and indeed some alternating air beds have the function of going both above and below capillary blood flow but in most cases the patients experience sweating and possible sea sickness along with pump noise.The cost of such equipment in most cases along with the actual running costs as well as the cost of maintenance / service contracts is far too expensive for the average person to outlay.

[0008] Looking at the aftercare homecare and community care markets, there are products already available outside a hospital setting that do a superb job of pressure sore prevention by utilising static systems such as foam, gel and spacer materials or a combination of gel and air. These products work well in the home but are not designed for the acute market where the problem of solving both pressure care and anti-skin shearing stem from. In this setting, there is a clear need for the introduction of a static system which is designed to cater for the hospital acute market.

[0009] Taking the above into account, there remains a need for a non-electrical static system for use in the treatment of both pressure care and skin shearing.

[0010] Remarkably, this has now been achieved by a layered material incorporating a first flexible fabric layer together with a second flexible fabric layer. The material can be formed into an overlay for a mattress (for example, by a manufacturer of a mattress).

[0011] Summary of the Invention

[0012] In accordance with a first aspect of the present invention there is provided a flexible layered material for use in an acute or hospital care setting, wherein the material comprises:

[0013] an outer skin;

[0014] a first flexible fabric layer having a thickness of about 6mm to about 10mm; and

[0015] a second flexible fabric layer having a thickness of about 17mm to about 25mm; wherein, in use, the outer skin is capable of facing a patient;

[0016] the first fabric layer is positioned between the outer skin and the second fabric layer and comprises a plurality of first densely packed substantially parallel fibrous ribsbetween a first sheet proximate to the outer skin and a second sheet distant to the outer skin; and

[0017] the second fabric layer comprises a plurality of second densely packed substantially parallel fibrous ribs between a third sheet proximate to the first fabric layer and a fourth sheet distant to the first fabric layer.

[0018] The invention achieves a material which alleviates 4-way sheering, distributes pressure evenly to minimize the risk of pressure ulcers, provides comfort to a user, and ensures durability and hygiene through appropriate materials.

[0019] Advantageously, the material can be used in the manufacture of a fully enclosed overlay, which can be placed over a mattress, and it has been found to be capable of combining good pressure relief plus diminishing shearing of contact areas.

[0020] Remarkably, it has been found that a unique longitudinal glide occurs between the first fabric layer and the second fabric layer when they are brought together and are under pressure from a patient's body weight, thereby allowing movement in particular under the ischial tuberosities when both sitting up in bed and laying in a supine position. The same movement of the two layers of materials is enjoyed when a patient lies on their side with the trochanter being the deepest point of immersion rather than the ischial tuberosities. This glide reduces sheering of the patient's tissue; assists in distributing pressure evenly to minimize the risk of pressure ulcers; provides comfort for the patient; and ensures durability and hygiene of the material.

[0021] Preferably, the outer skin defines an envelope around the first fabric layer and the second fabric layer. Preferably, the envelope is sealed along at least part of at least one edge by heat sealing, or welded by high frequency welding. More preferably, at least part of two edges are sealed by heat sealing, or welded by high frequency welding. Preferably, the two edges are opposite edges. Most preferably, all edges are sealed by heat sealing, or welded by high frequency welding.Advantageously, sealing or welding the edges alleviates the risk of infection by inhibiting ingress of bacteria. In addition, it complies with hospital infection control regulations. In this regard, mattresses and overlays for acute care settings should not have zippered openings, or other openings.

[0022] Preferably, the outer skin comprises or consists of a knitted fabric.

[0023] Preferably, the outer skin comprises or consists of a vapour permeable fabric. In one embodiment, the outer skin comprises or consists of polyester. In another embodiment, the outer skin comprises or consists of polyester and polyurethane.

[0024] More preferably, the outer skin comprises or consists of a knitted polyester, coated with an anti-microbial polyurethane coating. Preferably, the polyurethane is a thermoplastic polyurethane (TPU). This is a class of polyurethane plastics with many properties, including elasticity, transparency, and resistance to oil, grease, and abrasion. It is a specialised fabric, which provides the advantages of durability, flexibility, and breathability. Advantageously, it is commonly used in medical applications due to its properties of being vapour permeable, waterproof, elastic and durable. Being vapour permeable, it allows moisture to escape, maintaining skin integrity and reducing the risk of maceration. Being waterproof it protects the inner layers of the material from liquids and contaminants. Being elastic and durable it ensures the mattress / cushion can withstand repeated use without losing its shape or functionality.

[0025] Preferably, the material comprises no further fabric layers.

[0026] Preferably, the first flexible fabric layer has a thickness of about 7mm to about 9mm, more preferably about 8mm.

[0027] Advantageously, it has been found that the first flexible fabric layer provides initial soft cushioning and comfort to the user.Preferably, the second flexible fabric layer has a thickness of about 19mm to about 21mm, more preferably about 20mm.

[0028] Advantageously, it has been found that the second flexible fabric layer offers additional support and helps in evenly distributing the body weight of a patient, thereby alleviating high-pressure zones that can lead to ulcers.

[0029] Preferably, the first sheet comprises or consists of polyester.

[0030] Preferably, the second sheet comprises or consists of polyester.

[0031] Preferably, the first flexible fabric layer comprises or consists of polyester.

[0032] Preferably, the third sheet comprises or consists of polyester.

[0033] Preferably, the fourth sheet comprises or consists of polyester.

[0034] Preferably, the second flexible fabric layer comprises or consists of polyester.

[0035] Advantageously, polyester provides the advantages of resilience, comfort, and breathability. In addition, the thicknesses of the polyester layers have been found to provide excellent pressure distribution and cushioning. Furthermore, it has been found that polyester materials maintain their shape and can be washed at a temperature of 92°C.

[0036] Preferably, the first flexible fabric layer has mass per m2of about 600g / m2to about 800 g / m2, more preferably about 650g / m2to about 750g / m2, most preferably about 700g / m2.

[0037] Preferably, the second flexible fabric layer has mass per m2of about 900g / m2to about 1200g / m2, more preferably about 1000g / m2to about 1100g / m2, most preferably about 1050g / m2.Preferably, the first flexible fabric layer is joined to the second flexible fabric layer by one or more stitches. Preferably, the stitches include one or more straight stitches.

[0038] Preferably, the material has a length being a distance between a first set of two parallel planes defined at a proximate end and a distant end of the material respectively with reference to a longitudinal axis of the material, and a width being a distance between a second set of two parallel planes defined at sides of the material, each plane of the second set being substantially perpendicular to the planes of the first set, the material defining a substantially planar surface, wherein the stiches are provided adjacent or at the ends of the material through the first fabric layer and the second fabric layer between the first woven sheet and the fourth woven sheet.

[0039] Advantageously, the stitches provide the advantage of ensuring structural integrity and flexibility of movement of the material for use in a mattress or cushion.

[0040] Preferably, stitches extend along at least one end of the fabric layers. Preferably, stitches extend along both ends of the fabric layers. More preferably, the stitches additionally extend from the ends of the fabric layers at least partially down at least one side of the fabric layers. Most preferably, the stitches extend from the ends of the fabric layers at least partially down each side of the fabric layers. This provides the advantage of reinforcing the structure of the material and preventing the internal fabric layers from shifting or bunching up during use.

[0041] Advantageously, the stitches provide the benefits of enhanced stability, flexibility and durability. In this regard, the stitches maintain the position of the internal polyester layers relative to each other, ensuring consistent support and pressure distribution. Only partially stitching the sides of the fabric layers ensures that the two layers of fabric may glide across each other without being fixed across the entire perimeter, reducing shear on the patient. Furthermore, reinforced stitching prolongs the life of the mattress / cushion by preventing wear and tear from daily use.Preferably, an edge of the first flexible fabric layer and / or an edge of the second flexible fabric layer is overlocked or overcast. This provides the advantage of reducing the risk of one or more fibres piercing through the outer skin.

[0042] Preferably, the outer skin comprises a knitted yarn and the first woven sheet comprises a warp and a weft, wherein the yarn of the outer skin is arranged parallel with the weft of the first woven sheet.

[0043] Preferably, the second woven sheet comprises a warp and a weft and the third woven sheet comprises a warp and a weft, wherein weft of the second woven sheet is arranged parallel with the weft of the third woven sheet.

[0044] By aligning the yarn and the wefts in this way, it provides the advantages of adherence, and movement accommodation. In this regard, the alignment ensures that the outer skin adheres well to the first fabric layer, creating a cohesive unit. In addition, the alignment facilitates a coordinated movement between the outer skin and the first and second fabric layers, which is essential for reducing shear forces.

[0045] In use, when a patient located on the material moves position, the material's design allows for a slight glide between the surfaces of the fabric layers in an up and down motion. This movement significantly reduces shear forces as movement of the fabric layers relative to each other absorbs mechanical energy that would otherwise be applied directly to the patient's points of greatest pressure - this is typically the ischial tuberosities (the bony prominences of the pelvis). In an embodiment, the outer skin is manufactured with an opening at two ends, or just one end, through which can be inserted the first and second fabric layers. Preferably, after the first and second layers of fabric have been inserted, the ends of the outer skin are welded together. The first and second layers of fabric accommodate a glide against each other. The outer skin adheres to the first layer of fabric by providing the inside of the outer skin with an adhesive surface. This results in movement of the outer skin and the first fabric layer together relative to the second fabric layer when the body of a patient moves on the mattress.In a second aspect, the invention provides an overlay for a mattress comprising or consisting of the flexible layered material of the invention.

[0046] In a third aspect, the invention provides a mattress comprising the overlay or the flexible layered material of the invention.

[0047] Preferably, the mattress includes an interliner, also referred to as an inner barrier, or sometimes a platilon liner. Preferably, the interliner comprises a zipped cover for a mattress. Preferably, the interliner is of colourless fabric. This provides the advantage that a nurse or infection control inspector can inspect the foam or inner material of a mattress. In this regard, the interliner is capable of being removed periodically, for example weekly or monthly.

[0048] Preferably, the interliner is manufactured of transfer coated polyurethane (PU) fabric. Preferably, it is engineered specifically for the healthcare market. Preferably, the interliner is both water resistant and vapour-permeable, enabling liquids to be repelled from the surface of the interliner while reducing the risk of moisture build-up over time.

[0049] Advantageously, providing an interliner (also called an inner barrier) in a hospital bed mattress provides several critical safety, hygiene, and regulatory benefits as follows:

[0050] Infection control

[0051] The interliner acts as a fluid-proof barrier beneath an outer cover.

[0052] • It prevents blood, urine, wound drainage, and cleaning fluids from soaking into the material of the mattress.

[0053] • If fluids penetrate to the material of the mattress, the mattress becomes almost impossible to disinfect and can harbour bacteria, fungi, and viruses.

[0054] Protection when the outer cover fails

[0055] Outer mattress covers can be damaged by:

[0056] • Repeated cleaning with harsh disinfectants• Wear and tear

[0057] • Accidental punctures

[0058] The interliner provides the advantage of a second line of defence, ensuring the mattress remains safe even if the outer cover is compromised.

[0059] Compliance with healthcare regulations

[0060] Many standards and guidelines (e.g., CDC recommendations, NHS specs, Joint Commission expectations, and medical device standards like IEC / ISO) require or strongly recommend:

[0061] • A fluid-impermeable barrier

[0062] • A cleanable, inspectable mattress system

[0063] Without an interliner, a mattress often fails infection prevention audits.

[0064] Fire safety

[0065] Interliners are preferably manufactured of fire-retardant materials that:

[0066] • Slow flame spread

[0067] • Help the mattress meet hospital fire codes (such as CAL 117, BS 7177, or 16 CFR standards)

[0068] Extended mattress lifespan and cost control

[0069] By protecting the material of the mattress:

[0070] • Mattresses last longer

[0071] • Hospitals avoid costly replacements

[0072] • Risk of taking beds out of service due to contamination is reduced

[0073] Patient safety

[0074] A contaminated mattress can contribute to:

[0075] • Hospital-acquired infections (HAIs)

[0076] • Skin breakdown and pressure injuries

[0077] The interliner helps maintain a clean, safe surface for vulnerable patients.In a fourth aspect, the invention provides a cushion comprising the overlay or the flexible layered material of the invention.

[0078] Brief Description of the Drawings

[0079] The invention will now be further described with reference to the accompanying drawings in which:

[0080] Figure 1 shows an example of stitches across the ends of the material whilst providing partial support on the sides.

[0081] Figures 2 to 4 show images of an embodiment of the invention showing layers of the material;

[0082] Figures 5 and 6 show images of an embodiment of the invention showing layers of material and a cover placed over the material;

[0083] Figure 7 shows a side view of an embodiment of the invention;

[0084] Figure 8 shows a top view of an embodiment of the invention;

[0085] Figure 9 shows a bottom view of an embodiment of the invention;

[0086] Figure 10 shows a diagram of equipment used for comparative testing of the invention. It shows a sample of a material according to the invention, weight applied in a vertical axis, weight applied in a horizontal axis and a digital read out;

[0087] Figure 11 shows results of comparative testing on a Tactilus pressure sensitive map;

[0088] Figure 12 shows a test rig used for carrying out comparative testing;

[0089] Figure 13 shows measurements carried out using the test rig;Figure 14 shows a contact point between an embodiment of the material of the invention and the test rig;

[0090] Figure 15 shows a vertical load applied to an embodiment of the material of the invention using the test rig;

[0091] Figures 16 and 17 show graphs of test results obtained in Example 1;

[0092] Figure 18 shows a graph of test results obtained in Example 2; and

[0093] Figure 19 shows a graph of test results obtained in Example 3.

[0094] Detailed Description of the Invention

[0095] It will be appreciated that aspects, embodiments and preferred features of the invention have been described herein in a way that allows the specification to be written in a clear and concise way. However, unless circumstances clearly dictate otherwise, aspects, embodiments and preferred features can be variously combined or separated in accordance with the invention.

[0096] Within the context of this specification, the word "about" preferably means plus or minus 20%, more preferably plus or minus 10%, even more preferably plus or minus 5%, most preferably plus or minus 2%.

[0097] Within the context of this specification, the word "comprises" means "includes, among other things" and should not be construed to mean "consists of only".

[0098] Within the context of this specification, the word "substantially" means preferably at least 90%, more preferably 95%, even more preferably 98%, most preferably 99%.Within the context of this specification, the term "densely packed substantially parallel fibrous ribs" is interpreted to provide a mass per m2of about 600g / m2to about 800 g / m2, more preferably about 650g / m2to about 750g / m2, most preferably about 700g / m2for a first flexible fabric layer having a thickness of about 6mm to about 10mm and about 900g / m2to about 1200g / m2, more preferably about 1000g / m2to about 1100g / m2, most preferably about 1050g / m2for a second flexible fabric layer having a thickness of about 17mm to about 22mm.

[0099] Within the context of this specification an interliner is a layer of fabric placed between the main material and the lining of a mattress. It serves to enhance the mattress's insulation properties, providing a more comfortable sleeping environment by reducing heat transfer and sound insulation. The interliner can be made from various materials, including cotton, polyester, or a combination of both, and is designed to be easy to work with and install. It is particularly beneficial for mattresses that are used in areas with high humidity or moisture, as it helps to prevent the mattress from becoming too soft or sagging over time.

[0100] With reference to figures 1 to 9, in one embodiment, the invention provides a flexible layered material (1) for use in an acute or hospital care setting. The material comprises:

[0101] an outer skin (2);

[0102] a first flexible fabric layer (3) having a thickness of about 8mm; and a second flexible fabric layer (4) having a thickness of about 20mm; wherein, in use, the outer skin (2) is capable of facing a patient;

[0103] the first fabric layer (3) is positioned between the outer skin (2) and the second fabric layer (4) and comprises a plurality of first densely packed substantially parallel fibrous ribs (5) between a first woven sheet (6) proximate to the outer skin (2) and a second woven sheet (7) distant to the outer skin (2); and

[0104] the second fabric layer (4) comprises a plurality of second densely packed substantially parallel fibrous ribs (8) between a third woven sheet (9) proximate to the first fabric layer (3) and a fourth woven sheet (10) distant to the first fabric layer (3).The material (1) can be used in the manufacture of a fully enclosed overlay, which can be placed over a mattress.

[0105] The outer skin (2) consists of a vapour permeable fabric. In this regard, the outer skin consists of a knitted polyester, coated with an anti-microbial polyurethane coating. Preferably, the polyurethane is a thermoplastic polyurethane (TPU).

[0106] In an embodiment, the specification of the outer skin is shown in the table below:

[0107] Product Code Test Method

[0108] Knitted polyester, coated with antiN / A

[0109] Description

[0110] microbial, polyurethane coating

[0111] Polyester / TPU N / A

[0112] Composition

[0113] 120-240gr / m2(+ / -5%)

[0114] Weight

[0115] Hydrostatic Head / Waterproof > 950 hPa ISO EN 811

[0116] 390 g / m2 / 24 h ASTM E96-2016 Water Vapour Permeability

[0117] BS 7175:1989

[0118] Pass (Crib 5) Flammability

[0119] ok N / A

[0120] Dry Cleaning

[0121] 90“C N / A

[0122] Washing

[0123] Wipe with mild detergent. Wash or dry-clean using detergent up to 95oC. For disinfection use sodium hypochlorite upto concentrations of 1,000 parts per Cleaning and Care

[0124] million of active chlorine. Do not use biological or phenolic- based cleaners. Wash and dry completely before storage. Some surface wrinkling may Good effect JISL 1902:2008

[0125] Anti-bacterial

[0126] pH 6,9 PN-EN ISO 3071:2007 electrostatic properties

[0127] pass PN-EN 1149-3:2007 Tensil Strenth For Warp - N / 5 cm Min. 430 N TS 2008 EN ISO 1421 Tensil Strenth For Weft – N / 5 cm Min. 210 N TS 2008 EN ISO 1421 Tear Strength For Warp - N Min. 15 N TS EN ISO 4674-1

[0128]

[0129] Tear Strength For Weft - N Min. 15 N TS EN ISO 4674-1The first woven sheet (6) consists of polyester. In addition, the second woven sheet (7) consists of polyester. In this regard, the first flexible fabric layer (3) consists of polyester.

[0130] In an embodiment, the specification of the first flexible fabric layer (3) is shown in the table below:

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[0151] The third woven sheet (9) comprises or consists of polyester. In addition, the fourth woven sheet (10) comprises or consists of polyester. In this regard, the second flexible fabric layer (4) consists of polyester.

[0152] In an embodiment, the specification of the second flexible fabric layer (4) is shown in the table below:Gf NtRAl INFORMATION

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[0179] As shown in Figures 1, 8 and 9, the first flexible fabric layer (3) is joined to the second flexible fabric layer (4) by stitches (11). In this regard, the material (1) has a length being a distance between a first set of two parallel planes defined at a proximate end (12) and a distant end (13) of the material (1) respectively with reference to a longitudinal axis of the material, and a width being a distance between a second set of two parallel planes defined at first and second sides (14, 15) of the material (1), each plane of the second set being substantially perpendicular to the planes of the first set, the material (1) defining a substantially planar surface, and the stiches (11) are provided adjacent the ends of the material (1) through the first fabric layer (3) and the second fabric layer (4) between the first woven sheet (6) and the fourth woven sheet (10).As shown in Figures 1, 8 and 9, the stitches (11) extend from the ends (12, 13) of the material (1) at least partially along the sides (14, 15) of the material (1).

[0180] The outer skin (2) comprises a knitted yarn and the first woven sheet (6) comprises a warp and a weft, wherein the yarn of the outer skin (2) is arranged parallel with the weft of the first woven sheet (6). In addition, the second woven sheet (7) comprises a warp and a weft and the third woven sheet (9) comprises a warp and a weft, wherein weft of the second woven sheet (7) is arranged parallel with the weft of the third woven sheet (9).

[0181] In a second aspect, the invention provides an overlay for a mattress comprising or consisting of the flexible layered material (1) of the invention.

[0182] In a third aspect, the invention provides a mattress comprising the overlay or the flexible layered material (1) of the invention.

[0183] In a fourth aspect, the invention provides a cushion comprising the overlay or the flexible layered material (1) of the invention.

[0184] Combining the features of the invention has resulted in a material (1) for use in an overlay, mattress or cushion that is structurally robust, effective in reducing shear forces, and resistant to fluid ingress. The integration of stitching (11), weave alignment, and high-frequency welding ensures that the mattress / cushion of the invention not only provides comfort but also enhances the overall health and wellbeing of individuals at risk of pressure ulcers.

[0185] Examples

[0186] To provide evidence in support of the invention, the material of the invention has been subjected to a series of tests to evaluate its performance in real-world conditions. The following tests have been carried out and they are described in detail below.Pressure Distribution Test

[0187] • Objective: To measure how effectively the cushion distributes pressure.

[0188] • Method: Use pressure mapping technology to visualize and measure pressure distribution when a standard weight is applied to the mattress / cushion.

[0189] • Expected Outcome: The mattress / cushion should show even pressure distribution with no significant high-pressure points.

[0190] Durability Test

[0191] • Objective: To assess the mattress / cushion's ability to retain its shape and functionality over time.

[0192] • Method: Conduct cyclic loading tests where the Mattress / cushion is repeatedly compressed and decompressed to simulate extended use.

[0193] • Expected Outcome: The mattress / cushion should retain its structural integrity and performance characteristics after extensive use.

[0194] Breathability and Moisture Management Test

[0195] • Objective: To evaluate the cushion's ability to manage moisture and maintain a comfortable microclimate.

[0196] • Method: Measure the moisture vapour transmission rate (MVTR) of the VP material and perform user trials to assess comfort.

[0197] • Expected Outcome: The mattress / cushion should demonstrate high MVTR and positive feedback regarding comfort and moisture management from users.

[0198] The material, overlay, mattress or cushion of the invention, which comprises dual layers of polyester enclosed in a vapour permeable material, provides effective pressure relief and comfort for individuals at risk of pressure ulcers. The data obtained in support of the invention highlights the potential of the material, overlay, mattress or cushion to distribute pressure evenly, manage moisture effectively, and withstand prolonged use.By addressing the key factors that contribute to pressure ulcer formation, the invention represents a significant advancement in acute pressure care and anti -shea ring, promising improved quality of life for individuals with limited mobility.

[0199] Example 1

[0200] A 250mm square sample of the material of the invention was supplied and a test rig was designed to allow for testing, this would apply an independent vertical and horizontal load, under controlled conditions.

[0201] A diagram of the test rig is shown in Figure 10. The Figure shows the material sample (1), vertical axis of test (16), horizontal axis of test (17) and the digital read out (18).

[0202] The material (1) is designed to reduce shear stress on a patient's skin, reducing the risk of bedsores and other trauma due to prolonged immobility. The material is assembled in multiple layers and differing materials, the individual layers are chosen for various properties, cushioning, lateral flexibility, sealing, etc.

[0203] The layers (3, 4) of the material (1) are minimally stitched (11) around the mattress perimeter, to allow for the maximum movement, under side loads.

[0204] Ideally, material (1) should allow no more than 50mm lateral movement along the longitudinal axis of the material.

[0205] Figure 11 shows a Tactilus pressure sensitive map (19), showing the pressure distribution of a patient on a sample of the material (1) of the invention as a heat map, with a resolution of 35x32mm squares.

[0206] The highest load detected was 35mmhg, this is equivalent to 0.0475kg / cm2. The squares of the test described below are 3.5x3.2cm, so each have a total area of 11.2cm2, this means a load of 0.532kg per 3.5x3.2cm square.We can see from the data in Figure 11 that the highest loads were spread over an area of around 3 squares, so for the best simulation, on a smaller sample, the area of the contact point was increased and the weight was increased, to maintain the correct pressure.

[0207] The test rig (20) shown in Figure 12 was assembled with similar construction and mechanisms to a typical 3d printer, with a horizontally sliding bed (21) that holds the mattress sample (1) and a vertically sliding platform (22), that holds a weight (23) to simulate the weight of a patient. Side loads are applied to the bed and mattress, by pulling on a cord (24) and pulley (25) system. This allowed the side load to be applied vertically, by an accurate digital balance scale (18).

[0208] The frame (26) is constructed from high precision, aluminium extrusion and is securely bolted together, to form a rigid structure. The 2 axes of the sliding elements run on reciprocating ball linear slides, these are similar to what would be used in a CNC machine for example and move very smoothly under load.

[0209] As shown in Figure 13, a linear encoder (18), similar to digital Vernier calliper, is mounted to the frame (26) and records the exact position of the bed (21), to an accuracy of 0.01mm. This is displayed on an LCD screen on the opposite side of the rig (20). This shows us in real time, the exact horizontal displacement of the mattress sample (1), for a given load.

[0210] As mentioned above, a digital spring balance type scale was used to apply the horizontal load.

[0211] As shown in Figure 14, initial tests were conducted with a contact point (27) that matched the 35x32mm sensor size of the Tactilus pressure mat (19) shown in Figure 11, however the rig (20) was designed to accept a wide range of footprints, which could be easily swapped in and out of the test rig (20).After initial testing, a larger footprint was tested that represented 9 squares in a 3x3 configuration, as this gave more realistic results.

[0212] As shown in Figure 15, vertical load tests were carried out. For simplicity and fine adjustments, a 5ltr container (28) filled with water was used to apply consistent loads on to the vertical axis (16) of the test rig (20), which in turn applied the load vertically to the material (1).

[0213] As the tests are directed at testing pressures, the weight was increased with the footprint (23) of the test rig (20), so with our 9 square 3x3 mattress contact, we needed to apply 4788g, to maintain the correct maximum pressure equivalent in millimetres of mercury.

[0214] A table showing the results obtained is shown below.Mattress testing

[0215] 3x3 contact pad at an equivalent of 30mm of mercury / inch

[0216] Mattress oriented long ways, open end at top

[0217] Side load (kg) Movement (mm)

[0218] 0 0

[0219] 250 0.2

[0220] 500 0.56

[0221] 750 0,56

[0222] 1000 1.14

[0223] 1250 1.85

[0224] 1500 2.11

[0225] 1750 2.11

[0226] 2000 3.79

[0227] 2250 3.79

[0228] 2500 4.63

[0229] 2750 5.4

[0230] 3000 11.87

[0231] 3250 14.9

[0232] 3500 22.76

[0233] 3750 24.6

[0234] 4000 33.36

[0235] 4250 42.92

[0236] 4500 47.34

[0237] 4750 52.07

[0238]

[0239] 5000 53.17

[0240] The results were plotted as a graph and this is shown in Figure 16.

[0241] The results showed a maximum of 53.17mm of horizontal displacement at 5kg side load, this is almost exact match for the results desired, so the result of the test was positive. Note the 2 stage reaction of the material, as shown by the kink in the line shown in the graph in Figure 16.

[0242] The above test was repeated and a table showing the results obtained in shown below.Mattress testing

[0243] 3x3 contact pad at an equivalent of 30mm of mercury / inch

[0244] Matress oriented longways, open end attop

[0245] Side load (kg) Movement (mm)

[0246] 0 0

[0247] 250 0.16

[0248] 500 0.42

[0249] 750 0.69

[0250] 1000 1.02

[0251] 1250 2.08

[0252] 1500 2.25

[0253] 1750 3.55

[0254] 2000 4.2

[0255] 2250 4.36

[0256] 2500 4.98

[0257] 2750 6.7

[0258] 3000 10.35

[0259] 3250 16.11

[0260] 3500 23.25

[0261] 3750 26.02

[0262] 4000 31.62

[0263] 4250 42.92

[0264] 4500 48.01

[0265] 4750 49.88

[0266]

[0267] 5000 51.24

[0268] The results of the repeated test were plotted as a graph and this is shown in Figure 17.

[0269] The results showed a maximum of 51.24mm of horizontal displacement at 5kg side load, very similar to the previous test and in-line with expectations again.

[0270] Test 1 conclusion:

[0271] The displacement of the material in terms of its total movement, matched the anticipated outcome very well, the goal being to have a 50mm displacement, the tests showing 53 and 51mm.The graphs of the results shown in Figures 16 and 17 show a definite kink at about the 3kg mark. Without wishing to be bound by theory, it is believed before this the materials themselves were deflecting, and after this the materials slide over each other. The movement between the cushioned layers and the outer skin, seems to be equal and they appear to move uniformly.

[0272] At the 5kg load level, the material started to roll, therefore further tests were not possible or accurate.

[0273] Example 2

[0274] An embodiment of the material (1) of the invention was tested to measure the deflection of the material (1) across the shorter axis of the material, i.e. side to side, to simulate the patients left and right. The material (1) of the invention is intended to allow glide between layers primarily in the end to end direction, i.e. the longitudinal axis of the material, so this deflection was expected to be much lower.

[0275] A table showing the results obtained in shown below.Mattress testing

[0276] 3x3 contact pad at an equivalent of 30mm of mercury / inch

[0277] Mattress oriented sideways, open end at top

[0278] Side load (kg) Movement (mm)

[0279] 0

[0280] 250 0

[0281] 500 0.05

[0282] 750 0.07

[0283] 1000 0.2

[0284] 1250 0.35

[0285] 1500 0.35

[0286] 1750 0.67

[0287] 2000 1.08

[0288] 2250 1.08

[0289] 2500 2

[0290] 2750 2.1

[0291] 3000 2.31

[0292] 3250 2.9

[0293] 3500 3.03

[0294] 3750 3.36

[0295] 4000 3.36

[0296] 4250 3.44

[0297] 4500 13.49

[0298] 4750

[0299]

[0300] 5000

[0301] The results were plotted as a graph and this is shown in Figure 17.

[0302] Test 2 conclusion:

[0303] Less displacement was expected for this test and the results showed significantly less movement, the mattress moved only 3.44mm until a 4.5kg load, at which it rolled and the displacement increased significantly.

[0304] The mechanical requirements of 50mm of displacement, are only specified in the long axis of the mattress, laterally there is no specific figure required, however this testdoes show the mattress is directional and it is expected that it would be less likely to kink, or gather up under a patient.

[0305] Example 3

[0306] A test was carried out to measure the compression of the material (1) under a series of loads. The loads were applied vertically only, with no side loading.

[0307] For these tests the 9 square 3x3 footprint contact was used, with the weight increasing from 1kg to 5kg. The mattress sample (1) has a resting height of 25.8mm, the compression was measured off an adjustable reference point on the test rig. The compression was calculated as a difference.

[0308] The results are shown in the table below.

[0309] Mattress testing

[0310] 3x3 contact pad at an equivalent of 30mm of mercury / inch

[0311] VE! t< c i defied io u* the iHdttteiS, U fid el -1 Sei lei fif lOJClS

[0312] Vertical load (g) Height of mattress (mm) Deflection (mm)

[0313] 0 25.8 0

[0314] 1000 25.32 0.48

[0315] -. IM! ' <

[0316] 2000 25.05 0.75

[0317] 2500 24.75 1.05

[0318] 3000 24.65 1.15

[0319] 3500 24.11 1.69

[0320] 4000 23.89 1.91

[0321] ’. JL J: > JI_.

[0322]

[0323] The results were plotted as a graph and this is shown in Figure 19.

[0324] The results show that compression shows a fairly linear progression, shown by the straight graph. In addition, subjective tests indicate that the actual movement under a patient is expected to be low.Test 3 conclusion:

[0325] The purpose of this test was to check whether the material would fail, or collapse under load and the test shows this is very unlikely, at the levels of pressure shown in the supplied data.

[0326] In the tests conducted, the material is only compressing around 10% and therefore, even under the sort of load tested, the material is not expected to lose its ability to provide lateral movement as we have demonstrated in the test described in Example 1.

[0327] Based on the results obtained in all of the Examples described above, an estimate of the maximum theoretical patient weight was calculated.

[0328] Maximum patient weight estimation:

[0329] The previous tests have been based on the pressure data supplied, in this case the patient simulated was a 70-72kg user of average height.

[0330] From this we can extrapolate the pressures applied by a larger user, up to a maximum recommended patient weight of 150kg, though it is necessary to make a number of assumptions:

[0331] Assumption 1: A heavier patient is the same size on the material, this is obviously unlikely, the larger patient would be significantly wider and therefore their weight would be more evenly distributed. The test provides a good worst case scenario.

[0332] Assumption 2: A heavier patient applies the same size loads in the same areas. Again this is unlikely since a larger patient would be expected to be wider and softer, therefore more evenly distributed. Again the test provides a good worst case scenario.

[0333] In view of the above, the weight on the test rig was increased, proportionally to simulate the weight of the heaviest intended patient.Maximum patient weight estimation findings:

[0334] Under the maximum pressure exerted on the material for a simulated 70kg user, the sample compressed 2.06mm.

[0335] Increasing the load on the sample to 10.8kg simulates a 150kg patient, and this resulted in 3.46mm of compression.

[0336] Tests were also conducted at a simulated 158.7kg, or 25 stone, which required an 11.3kg load, and this resulted in only 3.51mm of compression.

[0337] A further test was carried out to simulate a patient of 250kg and this resulted in only 5.58mm of compression.

[0338] Maximum patient weight conclusion:

[0339] The tests conducted showed relatively little difference in compression, with the mattress compressing no more than 15% of its total depth. This is based on the pressure data supplied and may differ if the patient's position changed significantly, from the supine position, however generally there is a good safety margin, even at the highest recommended patient weight.

[0340] The bariatric 250kg test is less accurate than the previous tests, but still appears to also be acceptable, the material is compressed from 25.8 to 20.22mm, giving a 5.58mm compression. The mattress does not bottom out until it is compressed from 25.8 to around a 6mm total height (i.e. approx. 19mm compression), so there is still plenty of cushioning available when the 250kg weight is applied and compresses the mattress by only 5.58mm.

[0341] The tests showed that horizontal displacement of the material in terms of its total movement, was about 50mm in a longitudinal direction at 5kg side load. In addition, at 90 degrees to the longitudinal axis of the material there was 3.44mm displacement in a lateral direction until a 4.5kg load. Furthermore, the tests showed a linearprogression of compression relative to vertical load. The compression was 2.06mm under 5kg load. Extrapolating from the data, the maximum recommended patient weight would be about 150kg. In addition, even with a projected patient weight of 250kg the mattress compressed by only 5.58mm and did not "bottom out".

[0342] The above described embodiments have been given by way of example only, and the skilled reader will naturally appreciate that many variations could be made thereto without departing from the scope of the invention.

Claims

1. CLAIMS1. A flexible layered material for use in an acute or hospital care setting, wherein the material comprises:an outer skin;a first flexible fabric layer having a thickness of about 6mm to about 10mm; anda second flexible fabric layer having a thickness of about 17mm to about 22mm; wherein, in use, the outer skin is capable of facing a patient;the first fabric layer is positioned between the outer skin and the second fabric layer and comprises a plurality of first densely packed substantially parallel fibrous ribs between a first sheet proximate to the outer skin and a second sheet distant to the outer skin; andthe second fabric layer comprises a plurality of second densely packed substantially parallel fibrous ribs between a third sheet proximate to the first fabric layer and a fourth sheet distant to the first fabric layer.

2. A flexible layered material according to claim 1, wherein the outer skin defines an envelope around the first fabric layer and the second fabric layer.

3. A flexible layered material according to claim 2, wherein the envelope is sealed along at least part of at least one edge by heat sealing, or welded by high frequency welding.

4. A flexible layered material according to claim 3, wherein at least part of two edges are sealed by heat sealing, or welded by high frequency welding.

5. A flexible layered material according to any one of the preceding claims, wherein the outer skin comprises or consists of a knitted fabric.

6. A flexible layered material according to any one of the preceding claims, wherein the outer skin comprises or consists of a vapour permeable fabric.

7. A flexible layered material according to any one of the preceding claims, wherein the outer skin comprises or consists of polyester.

8. A flexible layered material according to any one of claims 1 to 6, wherein the outer skin comprises or consists of polyester and polyurethane.

9. A flexible layered material according to any one of claims 1 to 6, wherein the outer skin comprises or consists of a knitted polyester, coated with an antimicrobial polyurethane coating.

10. A flexible layered material according to any one of the preceding claims, wherein the material comprises no further fabric layers.

11. A flexible layered material according to any one of the preceding claims, wherein the first flexible fabric layer has a thickness of about 7mm to about 9mm.

12. A flexible layered material according to any one of the preceding claims, wherein the second flexible fabric layer has a thickness of about 19mm to about 21mm.

13. A flexible layered material according to any one of the preceding claims, wherein the first sheet comprises or consists of polyester.

14. A flexible layered material according to any one of the preceding claims, wherein the second sheet comprises or consists of polyester.

15. A flexible layered material according to any one of the preceding claims, wherein the first flexible fabric layer comprises or consists of polyester.

16. A flexible layered material according to any one of the preceding claims, wherein the third sheet comprises or consists of polyester.

17. A flexible layered material according to any one of the preceding claims, wherein the fourth sheet comprises or consists of polyester.

18. A flexible layered material according to any one of the preceding claims, wherein the second flexible fabric layer comprises or consists of polyester.

19. A flexible layered material according to any one of the preceding claims, wherein the first flexible fabric layer is joined to the second flexible fabric layer by one or more stitches.

20. A flexible layered material according to claim 19, wherein the stitches are straight stitches.

21. A flexible layered material according to any one of claims 19 to 20, wherein the material has a length being a distance between a first set of two parallel planes defined at a proximate end and a distant end of the material respectively with reference to a longitudinal axis of the material, and a width being a distance between a second set of two parallel planes defined at sides of the material, each plane of the second set being substantially perpendicular to the planes of the first set, the material defining a substantially planar surface, wherein the stiches are provided adjacent or at the ends of the material through the first fabric layer and the second fabric layer between the first sheet and the fourth sheet.

22. A flexible layered material according to any one of claims 19 to 21, wherein the stitches extend from the ends of the material at least partially along the sides of the material.

23. A flexible layered material according to any one of the preceding claims, wherein an edge of the first flexible fabric layer and / or an edge of the second flexible fabric layer is overlocked or overcast.

24. A flexible layered material according to any one of the preceding claims, wherein the outer skin comprises a knitted yarn and the first sheet is woven and comprises a warp and a weft, wherein the yarn of the outer skin is arranged parallel with the weft of the first woven sheet.

25. A flexible layered material according to any one of the preceding claims, wherein the second sheet is woven and comprises a warp and a weft and the third sheet is woven and comprises a warp and a weft, wherein the weft of the second woven sheet is arranged parallel with the weft of the third woven sheet.

26. An overlay for a mattress comprising or consisting of the flexible layered material of any one of the preceding claims.

27. A mattress comprising the flexible layered material of any one of claims 1 to 25 or the overlay of claim 26.

28. A mattress according to claim 27, wherein the mattress includes an interliner.

29. A mattress according to claim 28, wherein the interliner comprises a zipped cover for a mattress.

30. A mattress according to claim 27 or 28, wherein the interliner is of colourless fabric.

31. A mattress according to any one of claims 27 to 30, wherein the interliner is manufactured of transfer coated polyurethane (PU) fabric.

32. A cushion comprising the flexible layered material of any one of claims 1 to 25 or the overlay of claim 26.

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