Devices for prevention of pressure ulcers

Abstract

A support surface, such as an underpad, for preventing pressure sores in a patient is a multi-layer textile assembly having a skin contact layer formed from a fabric of synthetic filament yarns woven to provide air permeability and moisture vapor permeability and having a thickness of less than 1 mm. An absorbent middle layer is formed from a breathable microfiber fabric woven to provide for moisture transition from an upper surface of the middle layer to a bottom surface of the middle layer. The skin contact layer and the middle layer are stitched together using a stitching pattern optimized to produce an open pattern with minimal puckering. A bottom layer is formed from a breathable, waterproof fabric woven from synthetic yarn to produce a moisture vapor transfer rate within the range of 5,000 to 20,000 grams per meter squared per 24 hours. The three layers are attached together around their outer edges.

Description

RELATED APPLICATIONS[0001]This application claims the priority of U.S. Provisional Application No. 60 / 973,643, filed Sep. 19, 2007, which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]Pressure ulcers can develop in a person who is bedridden, confined to a wheelchair, or otherwise subject to extended periods of immobility. An estimated 1.3 to 3 million patients in the United States have pressure ulcers; incidence is highest in older patients, especially when hospitalized or in long-term care facilities. Both intrinsic and extrinsic factors may be involved in the development of such pressure ulcers. Aging increases risk, in part because of reduced subcutaneous fat and decreased capillary blood flow. Some additional intrinsic factors include impaired mobility, incontinence, skin condition, nutrition, and altered mental status.[0003]Exposure to pressure is one extrinsic factor. When a bony prominence is pressed against a support surface of a bed or...

AI Technical Summary

Benefits of technology

[0015]The present invention addresses one aspect of the aforementioned needs by providing a multi-layered textile assembly that possesses all of the qualities that are important for reducing the risk of pressure sore formation through improved comfort, moisture wicking, breathability, shear reducing, rapid drying and anti-microbial, while being durable, launderable and lightweight.

[0018]In an exemplary embodiment, a three-layer textile assembly includes an upper layer, typically for direct skin contact or contact with the patient's gown or pajamas, which is a thin (<1 mm), lightweight (˜2.5 ounce) polyester that is breathable, non-shearing, anti-microbial, moisture wicking and quick drying. Examples of appropriate fabrics for this upper layer include the fabric described in U.S. Pat. No. 6,277,770 of Smith, (incorporated herein by reference) which is assigned to Precision Fabrics, Inc. (Greensboro, N.C.), or similar fabrics made by Precision Fabrics or by Teijin Fibers Ltd. (Tokyo, Japan), such as Teijin's NANOFRONT™ polyester fiber. The middle layer of the assembly is an absorbent, breathable microfiber layer that is flexible and conforms to the body, with a thickness on the order of 1.5 to 3.5 mm, more preferably less than 3 mm and most preferably less than 2 mm. A preferred microfiber material has a density of 180-340 gm / m2, such as the microfiber materials used in the AQUIS® products available from Britanne Corporation or SILVERSTAR2000 microfiber fabric available from Silverstar Corporation Ltd. (Welcron Company Ltd.) (South Korea). Such microfiber fabrics absorb liquid faster than cotton by the capillary effect created within tiny spaces between the threads and are able to dry rapidly by communicating the liquid away from the source. The outer layer of the assembly is a thin, lightweight, waterproof, breathable fabric such as the polyester or nylon fabrics coated with polyurethane. Such fabrics are available from Young Poong Filltex Co. Ltd. (South Korea), Formosa Taffeta Company, Ltd. (Taiwan), or PORELLE® membranes available from PILMembranes Ltd. (formerly Porvair International)(U.K.)

[0019]A factor that affects the smoothness and comfort of the surface is the assembly method used for combining the multiple layers and finishing the edges of a pad or cushion. The assembly method also effects launderability and drying time. In the preferred embodiment, the multi-layer fabric is stitched using a smooth polyester thread to form a quilted pattern with features and dimensions that are optimized to minimize puckering or bunching, minimize washing and drying time, while maximizing comfort, durability and breathability. Seams, if any, should be free of puckering and are preferably limited to those used for finishing the outer edges of the pad, or the sides of a cushion or mattress cover, so that the skin contact surface is substantially seamless. In one embodiment, a friction-enhancing strip, such as silicone or other rubber-like synthetic material, may be formed or attached to selected areas on the outer edges of the bottom side of a pad to facilitate gripping by a care giver when the patient is moved or bedding is changed. The stitching or other attachment method used to apply the grip strip should have minimal impact on the smoothness of the upper skin contact surface.

Problems solved by technology

Pressure ulcers can develop in a person who is bedridden, confined to a wheelchair, or otherwise subject to extended periods of immobility.

Aging increases risk, in part because of reduced subcutaneous fat and decreased capillary blood flow.

The scope and cost of such pressure ulcers in the United States are significant.

Furthermore, no dollar amount can be placed on the cost of human suffering from this debilitating condition.

However, with staff / patient ratios typically found in many health care facilities, it may be impractical to expect all aspects of the AHCPR guidelines to be followed for all but high-risk patients.

Medical conditions that do not necessarily involve immobility can also increase the risk of the formation of pressure ulcers or similar types of sores.

Venous ulcers and arterial ulcers can also result from prolonged pressure and ischemia.

Most address a few of the problems, but none considers all of the conditions that can be encountered in patient care including shear forces, moisture management, bunching, surface texture, breathability, odor control, durability and launderability.

These pads frequently have cotton or synthetic covers and generally do not have moisture-wicking capability, increasing the risk of ulcer formation in an at-risk patient if the pad is not changed promptly when wet.

While shearing forces may be reduced, relative movement among the layers raises the opportunity for bunching, which can create lumps that increase pressure against the skin.

Furthermore, there is no provision for drawing and keeping moisture away from the skin.

The lack of breathability causes skin warming, which contributes to maceration of the skin.

The lack of breathability increases the risk of skin warming.

This approach also suffers from non-breathable outer layer.

Such systems can be quite costly and generally will be purchased for institutional usage more so that for in home use.

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