JPH02198553A - Supporting system for reducing decubital formation - Google Patents

Abstract

PURPOSE: To reduce forming of bedsore tumores, by forming a support system by flexible material impermeable against fluid contained in cavities and composing the same into a dimension and a form so that the center distance of expanded neighboring cavities is shorter than the two point discrimination threshold value of a human. CONSTITUTION: A mattress system 20 comprises an independent cavities' layer 21, which is above a heating element layer 22, a fiber layer 23, and a high frictional layer 24. The independent cavities' layer 21 has a multiplicity of cavities 27, which can be inflated by heating fluid filled into cavities by a means for heating the fluid to generate steam and inflate the cavities, and can be deflated by chilling the fluid. A means 28 for heating the heating element layer 22 and a means 29 for chilling it are used for heating and chilling the adjacent cavities 27, respectively, so that the cavities can be easily controlled to be inflated or deflated. A multiplicity of cavities 27 are formed of a soft material, and the center distance of neighboring cavities is made into a dimension and a form narrower than the two point discrimination threshold value of a human so that a user's weight can be supported without abutting on the base.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to support systems and associated devices for use in reducing skin damage in humans, and for those who are confined to a bed, wheelchair, etc. for a period of time, or who are otherwise completely or partially confined to a bed, wheelchair, etc. Relating to reducing the likelihood of formation of pressure sore ulcers in people with fixed limbs.

Briefly summarizing the invention, a support system is disclosed that reduces the potential for damage to human skin and thus the formation of pressure sore ulcers. This system comprises two sheets of flexible material joined together to provide a plurality of separate cavities that can be alternately and repeatedly inflated and deflated by using fluid contained in the cavities. Flexible materials are impermeable to fluids. The cavity is such that, in at least one of the width and length of the system, the distance between the centers of adjacent cavities is less than or equal to the human two-point discrimination threshold, and the support system extends downwardly between or within the bulging cavities. be of such size and shape as to be able to support the human body without impinging on it;
It also has cavities spaced apart. In a particular embodiment, the support system is in the form of a pine tress. The support system is
It may be used with respect to a person who is confined to a bed, wheelchair, etc. for a period of time, or who is otherwise fully or partially immobilized, including for therapeutic purposes.

As used herein, "support system" includes mattresses, cushions, pads, and other related supports, including support systems that may be used for therapeutic or other purposes.

"Bottoming out" means that the upper part of a cavity (cel+) touches the bottom or bottom part of the cavity due to the influence of weight, e.g. the weight of a person, and that the person is below the support system between the cavities. It concerns the collapse of a cavity in a clinical support system, such as in contact with a part.

"Human two-point discrimination threshold" is the minimum distance between two objects that can be distinguished by contact when placed on the skin and that an anatomical expert can understand. be measured. This is approximately 30 mm on the human back.

A person may become confined to a support surface, such as a bed, wheelchair, or other device, for a variety of reasons, such as as a result of injury or illness or as a result of the demands of a work item in one's employment. Elderly people may also be confined to beds or other devices for long periods of time.

BACKGROUND OF THE INVENTION Pressure ulcers, also referred to as pressure ulcers, pressure sores, and pressure sores, are a widespread problem in the field of health care and are quite costly in terms of individual human suffering and in financial cost to society. Pressure sore ulcers occur in a range of about 3 to about 17% in sick patients, and this increases to a range of 20 to 30% in sick elderly people [D. Norton et al., ``Study of Geriatric Nursing Problems in Hospitals'' , Churchill Livingstone
l LivingstoneEdinburgh (1
962) Ko. For patients with neurological damage, it ranges from 30-60% of patients [Rich
Ardson and Mayer, Gerontol, ), 19.235
~247 (1981); Taylor,
J, Gerontol, Nu
rs,) 6.389-391 (1980)].

Bedsore ulcers are localized cellular necrosis that tends to develop when soft tissue is compressed between bony protrusions and hard surfaces. External pressure acts by obstructing blood flow, resulting in ischemic damage. If there is an interruption in blood flow and therefore oxygen supply, a series of intracellular events occur,
This progresses to an irreversible stage if blood flow is not restored.

Ischemic injury results in cell death, or necrosis, and accumulation of cellular debris within tissues.

The most critical factors in the formation of bedsore ulcers are the intensity and duration of such pressure, and the relationship between these factors is generally considered to be a parabolic intensity-duration curve. If the patient is immobile and remains in the same position for a period of less than about 2 hours, ischemia is reversible, and in this case there is generally long-term or irreversible damage to the soft tissue, i.e., the skin over the bony prominence. It does not appear in subcutaneous tissues and muscles. However, if the period of immobility exceeds two hours, pressure sore ulcers, sometimes referred to as stage 1 pressure sore formation, begin to form. For this reason, it is the policy of many hospitals and laboratories to relocate patients approximately every two hours. However, this implementation is not entirely effective. Additionally, patients tend to be more dependent on caring for patients at home, and nursing care in such an environment is not possible 24 hours a day.

Both extrinsic and intrinsic factors are believed to act to reduce a tissue's resistance to pressure. Extrinsic factors that affect soft tissue include shear friction, moisture, and temperature. Factors that determine susceptibility to tissue damage include loss of sensitivity, impaired mobility, advanced age, malnutrition, muscle disease, anemia, ataxia, and infection.

Age-related skin changes that contribute to the formation of bedsore ulcers in older adults include flattened skin-epidermal junctions [Montagna and Carl
isle), Journal of Investigative Dermatology (J, of Investiga
tive Dermatology), 73.47~
53 (1979)], a decrease in the number of Langerhans cells [Kripke, Journal of the American Academy of Dermatology (J, of
American Academy or Derm
atology) l 4.149-155 (1986
)], reduced skin density that becomes relatively cell-free and vascular-free [Montagna and Carlisle;
supra], alternation in collagen and elastic gland miscellaneous [Shuster et al., British Journal of Dermatology]
f Dermatology) 93.639-643
(1975) l, sweating and decreased sebaceous gland function [Foster et al.
Age and Aging) 5.91-101(1
976); Plewig and Kligman, Journal of Investigative Dermatology 70, 314-317
(1978) and impaired immune response [Barrett et al., Clinical Immunology.
and immunopathology (C1inical Im
munology and immunopathol
ogy) 17.203-211 (1980)]. Versluysen [British Medical Journal]
Medical Journal) 292.1311-
[1313 (1985)] reported that more than 90% of patients with hip fractures of >70 degrees develop bedsore ulcers. Failure to treat bedsore ulcers is associated with mortality rates that are almost six times higher [Ree et al.
d), MD State Med,
) J, 30.45-50 (1981)]. Complications of bedsore ulcers include osteomyelitis and sepsis, with mortality rates of sepsis approaching 50% [Galpin et al., American Journal of Medicine (Aw+
Erican J-orMedicine) 6th Sat.
346-350 (1976); Sugman (Sug
erman) et al., Arc Quiz Met Rehabilitation (A
rch, Phys, Mad, Rehabil,)
66.177-179 (1985); Pryon (B
ryan) et al., Arch.

Intern, Mad, ) 143 2093-20
95 (1983)]. That is, bedsore ulcers are a potentially very serious problem in the field of health care.

There are a variety of effective systems designed to reduce pressure sore ulcer formation. Many of these work on one of two ideas, static tools such as foam-pine tresses,
These include air mattresses, water beds, and those that attempt to separate and distribute support from sheath skin or bony prominences, as well as active devices such as alternating air mattresses that function by alternating support pressure. Although such devices are an improvement over the use of conventional pinerests, further improvements in effectiveness and/or effectiveness of use are needed.

Many static devices have a limited useful life because they cannot be effectively cleaned for reuse by the same or other patients.

A severe problem with active devices and some static devices is that they cannot support the weight of the body on bony prominences. Under such circumstances, the support system collapses under the weight of the bony prominences, causing the protrusions to bottom out or "bottom" the pine tress. This occurs because such devices tend to consist of one or more cells of plastic material that can expand regardless of the cavity configuration. The force exerted by the bony protrusion over a relatively small area of the support device must cause the rest of the air bubble to expand a little to equalize the pressure on that bubble, resulting in the associated portion of the air bubble I'll crush it.

Another related cause is the configuration of the air chamber. Very often the bubbles are shaped into tubular or diamond-shaped or other shaped sections or cells that are fingered together so that when one section is filled with air, the adjacent section collapses. However, the bubble size of typical support devices of 5 cm or more is sufficient to lift the patient sharply enough from the pine tress beneath the device to apply effective alternating pressure, particularly over bony prominences. could not. Although the larger bubble dimensions of some devices have sufficient displacement, or height, to overcome this problem of downward protrusion [Bliss et al., in British Medical Journal, 394-397] (1
967)], which includes other problems. For example, in such cases, large surfaces of the body are left unsupported and the patient experiences discomfort and tension. Even a bubble size of 5 cm does not prevent small bony protrusions on the body from falling between the bulging bubbles and being located beneath or under the pine tress. In such tubes, higher pressures may be used to prevent downward impingement, but may result in patient comfort problems and alternating pressures may not be achievable. Other limitations to these devices relate to the frequency of cycles, and more particularly to the time required to inflate support cells and deflate adjacent cells. The long period of inflation and deflation eliminates a pressure relief phase of sufficient duration to allow normal blood flow and tissue recovery.

A support system has now been discovered that reduces the tendency for bedsore ulcer formation.

Accordingly, the present invention comprises a plurality of separate cavities in a single layer formed from a flexible material of selected dimensions and shapes; provided that the material is such that each cavity can be inflated and deflated alternately and repeatedly. sufficiently impermeable to the fluid contained in the cavity:
The cavities are sized and shaped and have a spacing between the cavities such that the distance between the centers of adjacent convex cavities in at least one of the width and length of the support system is less than a human two-point discrimination threshold. and to provide a support system capable of supporting the weight of a human being without sagging.

In an embodiment of the support system of the invention, the cavity does not result in a 2.5 kg spherical surface having a diameter of 2.67 cm placed on the support system impinging beneath the clinical support. of such shape and dimensions.

The invention further comprises: (a) a single layer of separate cavities formed from a flexible material of selected size and shape; The cavities are sufficiently impermeable to the fluids contained in the cavities so that they can be deflated; sized and shaped and with a spacing between the cavities narrower than the human two-point discrimination threshold; and capable of supporting the weight of a human being without impinging on either or between the bulging cavities; A support system is provided comprising: a support system abutting either or between the bulging cavities; and (b) means for inflating and deflating the cavities.

In an embodiment of the support system of the invention, the cavity is shaped such that a 2.5 kg spherical surface having a diameter of 2.67 cm placed on the support system does not impinge on the bottom of the support. and dimensions.

In other embodiments of the support system, the means for inflating the cavities is controlled such that when inflating one cavity, it deflates an adjacent cavity.

In other embodiments of the support system, the cavities can be independently inflated and deflated.

In another embodiment of the support system, the means for inflating the cavity is a compressor or a liquid that can be evaporated to inflate the cavity, in particular by the use of electrothermal elements or thermoelectric means.

In other embodiments of the support system, each cavity is of a geometric shape that precludes complete collapse of the cavity when deflated.

The present invention further comprises: (a) a single layer of a plurality of discrete cavities formed from a flexible material of selected size and shape; provided that the material allows each cavity to alternately and repeatedly inflate and deflate; The cavity is sufficiently impermeable to the fluid contained in the cavity such that the distance between the centers of adjacent convex cavities in at least one of the width and length of the support system is approximately the same as that of a human being. a support sized and shaped and having a spacing between cavities such that it is narrower than the two-point discrimination threshold; and capable of supporting the weight of a human being without impinging on any of the bulging cavities or between them; A support system is provided comprising in sequence: (b) a means for inflating and deflating the cavity; (C) a layer of cushioning material; and (d) a layer of material having a high coefficient of friction.

In an embodiment of the support system of the invention, the cavity is shaped such that a 2.5 kg spherical surface having a diameter of 2.67 cm placed on the support system does not impinge on the bottom of the support. and dimensions.

In other embodiments of the support system, a woven fabric layer, in particular a removable woven fabric layer, is located above the flexible material layer, provided that the woven fabric layer is between the moisture absorbing layer and the flexible material layer. . This moisture absorption layer is preferably a microporous film layer, preferably a disposable layer.

The present invention further provides an alternatively inflatable and deflated and formed from a flexible impermeable thermoplastic material and
A cavity is provided containing an inert liquid having a boiling point in the range of 50°C and further having means for heating and/or cooling the liquid.

In a preferred embodiment of the cavity of the invention, the liquid is one or more fluorocarbons or one or more liquids of the type developed to replace fluorocarbons for environmental reasons, but in particular such The fluorocarbons and liquids have boiling points in the range 10-40°C, especially 20-34°C.

Although the present invention is specifically described herein with reference to support systems and pine tress support systems, particularly in some end uses the system is not typically referred to as a support or pine tress, but rather is discussed below. It may be in the form of a sheet or other support as shown in FIG.

The invention will now be described with particular reference to the accompanying drawings: Figure 1 schematically shows part of a row of cavities of a clinical support system, all shown in an inflated state; The Figures schematically depict the cavity of Figure 1 in a partially deflated state; Figure 3 schematically depicts an embodiment of the support system of the invention; Figure 4 depicts a computer simulation of the cavity;
Figure 5 is a histogram of the data obtained in Example I; Figure 6 is a graph of the data obtained in Example ■; Figure 7 is a graph of the data obtained in Example ■. Figure 8 is a graph of the pressure profile as measured in Example ■; Figures 9A and 9B are schematic cross-sectional views of a support system with a long bulging tubular cavity and the use of the support system of the invention. FIG. 1O is a graph of temperature versus recovery time as measured in Example V; and FIG. 11 is a graph of temperature response of the tissue versus time as measured in Example II.

In FIG. 1, a row of cavities I is shown on a substrate 2, which is a layer of flexible material. The cavities l are separated by spaces 3, as indicated at 4, which are substantially smaller than the distance d between the centers of the cavities.

Although the cavity l is shown as long, either w
It should be understood that the cavity may be of any shape; nevertheless, the cavity may be of such a shape that the upper part of the cavity comes into contact with the lower part of the cavity under the influence of weight, for example the weight of the patient. It should be of a size and shape that eliminates ``dragging'' or precludes collapse of the cavity. An example of a cavity is shown as a computer simulation in FIG. In use, the cavity l is associated with means for inflating and deflating the cavity in a controlled manner. However, such means are not shown.

The cavity l of FIG. 1 can be inflated and deflated as shown in FIG. In the illustrated embodiment, the bulging cavity 11
They are separated by a hollow cavity 12. The distance between the centers of the bulging cavities is below the human two-point discrimination threshold, such that a person lying on the cavity cannot distinguish between the bulging and deflating contact of alternate cavities.

Furthermore, the patient generally cannot feel the expansion of cavity 11 and the contraction of cavity 12.

The pine tress system, shown generally as 20 in FIG. 3, consists of a closed cavity layer 21 on top of a heating element layer 22, a fibrous layer 23, and a high friction layer 24.

Above the independent cavity layer 21 is a woven fabric layer and an outer microporous layer. The independent cavity layer 21 has a plurality of cavities 27, which may be of the type shown in FIG.

Cavities 27 are shown elongated and aligned both axially and laterally of the cavity. However, the cavity may be of another shape and/or may have any arbitrary shape.

Cavities are referred to herein as "separate cavities." However, even if a cavity has the physical appearance of a separate cavity, any one cavity may be interconnected with one or more other cavities for purposes of cavity inflation and deflation. You should understand that it is good.

Cavity 27 can be inflated and deflated. Various means can be used to inflate and deflate this cavity. For example, the cavity is alternately supplied with a compressed gas, such as compressed air, at a pressure sufficient to inflate the cavity when in use;
It may be connected by tubing to a system that applies a vacuum to the cavity to the extent necessary to subsequently cool or collapse the cavity 27. The degree of vacuum applied may be small, ie just sufficient to collapse the cavity 27 to the extent that it no longer supports the patient on the pinerest system 20.

Compressors that supply compressed air tend to be noisy; alternatively, the supply of compressed gas may be from a source remote from the location where the pine tress system is used, such as a remote compressor or source of compressed air. Alternatively, alternate pressurization of the cavities may be applied to the liquid in the cavities by hydraulic means.

Examples of such liquids include water and silicone oil.

A preferred method of inflating and deflating cavity 27 is to introduce liquid into the cavity. If such a liquid is used, the liquid is heated, in particular by thermoelectric means, to produce vapor, which inflates the cavity 27. Such heating may raise the temperature of the liquid above its boiling point, but need not do so if sufficient pressure is generated to inflate the cavity 27. Upon cooling, the pressure within the cavity decreases and the cavity deflates. The liquid generates enough steam to
The cavity is selected to swell while remaining at a desired or predetermined temperature for a period of time. Additionally, the liquid may need to be selected with consideration to the location of end use. For example, in some places the temperature of the air surrounding the patient may be as low as about 18°C, while in other places the air temperature may reach high temperatures of about 40°C.

The liquid introduced into cavity 27 is preferably inert, non-toxic and non-flammable, and is of no concern to health care authorities, both with respect to the patient and personnel such as doctors and nurses attending the patient. Furthermore, the cavity 27 must be manufactured from a material that has adequate sealing properties against liquids so that a supply of liquid can be retained in the cavity for at least the expected period of use of the pine tress system. Such materials are referred to herein as opaque. As discussed herein, this material is a multilayer structure, including a coated structure to obtain acceptable impermeability. It is to be understood herein that the expected period of use of the clinical support system is six months or two years or more.

Examples of liquids introduced into the cavity are fluorocarbons, particularly mixtures of chlorofluorocarbons that exhibit a variation in vapor pressure over the temperature range used for inflation and deflation of the cavity 27, as well as chlorofluorocarbons for environmental reasons. Includes fluid types that can replace carbon, such as hydrochlorofluorocarbons. Fluorocarbons and hydrochlorofluorocarbons are commercially available from DuPont Canada under the trade name Freon, an example of which is shown in Product Designation 114.
．． Sold as 113.22.11, 123 and 141B.

The boiling point of the liquid should be in the range 0-50°C, preferably 10-40°C. Liquids with boiling points at the lower end of this range may be used, for example, for cooling purposes of the feet or other parts of the body. In certain embodiments, the liquid has a boiling point within the patient's comfort range, but below the normal human perspiration threshold, particularly in the range of 20-34°C.

The cavity 27 shown in FIG. 3 is of a liquid-containing type.Although the liquid can be heated solely by the body heat of the patient, it is preferable to equip it with electrical, especially thermoelectric, means for heating and cooling the liquid. It is.

In FIG. 3, a heating and cooling layer (thermoelectric layer) 22 located directly below the independent cavity layer 21 has heating and cooling means 28 and 29 that can be used to evaporate and condense the liquid. Although reference is made herein to a single heating and cooling layer, in some embodiments the layer may simply be a heating or cooling layer.

The heating and cooling means 28 and 29 are separate electrical heating circuits and cooperate with the adjacent cavity 27. i.e. heating and cooling means 28
are used for heating and cooling one cavity, and heating and cooling means 29 are used for heating and cooling an adjacent cavity.

One of the heating and cooling means 28 and 29 normally cooperates with each cavity so that the inflation and deflation of the cavity can be easily adjusted. Although only two heating and cooling means 28 and 29 can be used to adjust the entire pinerest system, different heating and cooling means can be used to adjust different parts of the pinerest system differently, e.g. using a microprocessor. Means may also be used. Preferably, the heating and cooling means operate at non-hazardous low voltages, ie substantially lower voltages than are normally used for heating and cooling purposes.

As mentioned above, the flexible material must be sufficiently impermeable to allow use of the open-ended bed support system for the expected period of use. The nature of the flexible material to meet such impermeability requirements will depend, among other things, on the fluid contained within the cavity of the clinical support system. For example, flexible materials suitable for use with inert gaseous fluids such as hydrochlorofluorocarbons are not suitable for use with water as the fluid, and vice versa, as those skilled in the art will know. The flexible material will preferably be a polymeric material, in particular a polymeric material that is laminated, thermally bonded or coated. In an embodiment, the flexible material is a thermoplastic polymer that is laminated or coated with a polymeric material that exhibits occlusive properties to liquids contained within the cavities of the clinical support system. In one embodiment, the polymeric material is linear low density polyethylene coated with or laminated with polyvinylidene chloride (PVDC). Such flexible materials exhibit both occlusive properties and flexibility and toughness, which are important with regard to the useful life of clinical support systems. In other embodiments, the flexible material is polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyester, polyamide, chlorosulfonated polyethylene, vinylidene fluoride, coated if necessary to obtain the required barrier properties. /hexafluoropropylene copolymer, polyurethane, ethylene/propylene/genterpolymer copolyether ester polymer, silicone rubber, butyl rubber and natural rubber.

Independent cavity layer 21 and thermoelectric layer 22 are shown in FIG. 3 as being located on fibrous layer 23. Layer 23 is intended to provide cushioning and good pressure distribution to the pinerest system. Layer 23 may be made from a wide variety of fibers or foam materials, including synthetic fibers such as polyamide, polyester and/or polypropylene, natural fibers such as cotton or wool fibers, including seedskin. In many cases the fibrous layer will be made from synthetic fibers that are bulky enough to provide a cushioning effect. An example of a suitable fiber is Quallofil polyester wt used in the manufacture of pillows.
It is m. In other embodiments, layer 23 may be an air pine tress.

In FIG. 3, fibrous layer 23 is shown positioned over friction layer 24. In FIG. The friction layer is provided for patient stability and safety reasons, especially to prevent the mattress system from slipping off the bed or other equipment in which it is used. Various materials, such as foamed thermoplastic polymers such as polystyrene, woven structures, Velcro, etc.
) materials are known.

The pine tress system shown in FIG. 3 has two layers superimposed on a separate hollow layer. The layer shown immediately adjacent to the free-standing cavity layer is a woven fabric layer 25, which is primarily a cover sheet or material for encasing the pine tress system of the present invention to preserve the integrity of the pine tress system as well as to prevent infection. It is intended as a sheet that imparts cleanliness and sterilization properties. The outer layer is a microporous layer 26 primarily intended for patient comfort. In particular, the microporous layer 26 allows sweat or other moisture associated with the patient to be removed from the vicinity of the patient and improves patient comfort. The microporous layer is intended to be a disposable layer. Woven fabric layer 25
and microporous layer 26 must be of a thickness and made of a material that does not interfere with the beneficial effects of operation of isolated cavity layer 22. In another embodiment, the outer layer may be a non-hard layer, especially one used for burn patients or for some therapeutic endpoints.

In using the pinerest system of FIG. 3, a patient is placed on the pinetress system in contact with the microporous layer, or a sheet or similar layer on the microporous layer. Preferably, the pinerest system is configured such that the cavities are arranged obliquely to the axis of the patient's body, in particular transversely. The cavities of the independent cavity layer are then heated, e.g. by applying heat using a layer of heating elements and then allowing the liquid to cool or actively cooling the liquid.
Alternately inflate and deflate.

The inflation and deflation cycle can vary from 1 minute to over 1 hour. However, this cycle should be more frequent than once every two hours. Different cycles may be used for different locations on the body. For example, locations where the body exerts more pressure may have shorter cycles than locations where less pressure is exerted, or different cycles may be used for therapeutic or other reasons. It would be expected that there would be different optimal cycle times depending on the intended use of the pine tress system or clinical support system.

Let us now refer to the cavity inflation and deflation cycle times. This cycle time is actually the amount required to move fluid from or into the cavity to actually inflate and deflate the cavity, or to condense or evaporate the fluid contained entirely within the cavity. including the time during which the cavity is inflated or deflated.

The duration of such fluid movement is limited, on the order of minutes long. The beneficial effects of cavity deflation, particularly the restoration of normal capillary flow in the skin layers adjacent to the deflated cavity, are primarily limited to periods when the cavity is not supporting the patient, which may be significantly shorter than the cycle time. It can be understood that The time of fluid movement relative to the cycle time becomes more important for short cycle times and must be considered when using the system of the present invention.

The inflation and deflation of the cavity is defined as 1 in this case.
It is generally described in the sense that as one cavity expands, the adjacent cavity deflates. It is to be understood that such inflation and deflation may occur simultaneously or sequentially, the latter including inflation of a cavity followed by deflation of an adjacent cavity. Furthermore, inflation and deflation may occur in waves passing across the clinical support system, including by peristaltic cycles. In some cases the patient may feel such wave or peristaltic movements, which for example may have a beneficial therapeutic effect and may be used for that or other reasons. In embodiments of the invention, bulging cavities may be surrounded by deflated cavities and vice versa, or one row of cavities may be bulging and the immediately adjacent row of cavities deflated, or Other configurations of expanded and deflated cavities may be used, provided that the expanded and deflated cavity arrangement can support the patient as described herein.

The pinerest system of the present invention alternately supports the patient in such a way that the patient experiences little or no heat from the alternating support provided by the pinerest system. That is, parts of the patient are alternately supported while lying in bed with little or no sensation of movement.

However, the spacing of the bulging cavities at a distance narrower than the human two-point discrimination value in at least one direction substantially eliminates or overcomes the sensation of any movement, and the pine tress system is intended for make it function according to the Furthermore, the pressure exerted on the patient's body juxtaposed to the deflated cavity is equal to the human internal capillary threshold, e.g. 20-32
mmHg or less. If this were not the case, there would be no circulation of blood to the special area of skin over the patient's deflated cavity, resulting in bedsore ulcers. Internal capillary pressure will vary from patient to patient and perhaps from patient section to patient.

The capillary pressure threshold, eg, the surface pressure above which a capillary would be expected to collapse, is about 30-32 mmHg, depending on the patient and the part of the patient that is in contact with the pine tress system.

Thus, in certain embodiments, it is important that the pressure exerted on the patient by the deflated cavity is less than about 20 mm Hg. Thus, the general requirement is that the pressure on the deflated cavity be below the capillary pressure threshold.

As mentioned above, the clinical support system of the present invention is capable of supporting a human body without impinging beneath any of the bulging cavities or between them.

In one embodiment, a human body is simulated on the surface of a sphere. In particular, the following method can be used to determine whether a clinical support system can support a human body without downward impingement. This method uses an actual diameter of 2.67c.
A jig with a spherical surface of m and an actual diameter of 7.5 cm (
jig).

The jig has a rod axially attached to the head opposite the spherical surface and suitable for receiving a weight. When testing, place the jig on the surface of the cavity so that it is centered over the deflated cavity and surrounded by two adjacent expanded cavities. Using a rod, an axially perforated weight is then applied to the jig until the surface of the jig contacts the lower surface of the deflated cavity.

The total weight of the jig at such times should be at least 2.5 kg. In such an environment, the cavity of the clinical support system is such that a weight of 2.5 kg and having a spherical surface of diameter 2°67 cm, placed on the clinical support,
It will be of such shape and size that it does not impinge on the underside of the clinical support system.

In Figure 9A, a human torso section, generally designated 40, is shown in a large bulging cavity 4Z, only one of which is shown in cross section.
is shown on a pinerest or cushion system 41 having a The bulging cavity 42 is shown as abutting down in the region of the location directly below the protrusion 44 of the barrel 45, and the gas in the bulging cavity 42 is directed from the region 43 where the cavity abuts down by the arrow 45. It is shown as being pushed in the direction of.

In contrast, in FIG. 9B, the barrel 40 is shown on the pinerest system of the present invention. This pine tress system consists of a single layer of cavities, shown as alternating bulging cavities 47 and deflated cavities 48. This hollow layer is attached to a flexible conductive layer 49.

The flexible conductive layer 49 has a series of heating and cooling circuits 50 therein, each circuit 50 located beneath either the bulging cavity 47 or the deflated cavity 48. In the illustrated embodiment, a heating and cooling circuit 50 below the bulging cavity 47
heats the gas in the cavity, while a heating and cooling circuit 50 below the deflated cavity 48 cools the vapor in the cavity.

A flexible layer 49 is shown overlying the fibrous layer 51. As shown in Figure 9B, the body has a bulging cavity 4.
7 A hollow 4 located above and deflated without touching the bottom
It is not in contact with the surface of 8. The barrel located above the deflated cavity 48 thus has no pressure on it. Activation of the heating circuit under the deflated cavity 48 and operation of the cooling circuit under the bulging cavity 47 is such that the part of the shell now shown in contact with the bulging cavity no longer contacts the cavity and vice versa. reverse.

The pine stress system of the present invention functions below both the capillary pressure threshold and the two-point discrimination threshold, thereby providing the patient with the benefit of increased blood circulation and a tendency to reduce bedsore ulcers, as well as comfort. . This pine tress type is
It is easy to use, especially when inflating and deflating cavities with liquids that can undergo phase changes, and is very clean and quiet to operate. In an embodiment, the present pine tress system is microprosensor operated and portable. Thus, it is suitable for use in wheelchairs and other portable systems, including those for the legs and other parts of the body, that provide mobility to the patient. Furthermore, the liquid in the cavity makes it possible to cool all or part of the patient's body by cooling, for example for use in external obliquity or as a cooling wrap for therapeutic reasons.

Although the support system of the present invention has generally been described herein with reference to therapeutic applications, ie, as a pine tress system,
It should be understood that the present support system may be used in a variety of forms and for a wide variety of end uses. In many such end uses, water systems are more commonly referred to by other names, including support systems, chairs, seats, and the like. For example, the systems described herein can be used in the healthcare, transportation, and recreational industries, examples of which include seats in aircraft, automobiles, offices, homes, trucks, and the like.

The following examples illustrate the invention.

Example ■ Holes of circular cross section and different diameters were cut from a series of metal plates of different thicknesses. The diameter of the hole was: 31.5
mm, 39.0++un, 45.0+nm and 51-3mm, this plate has a thickness of 4.2 mm, 5.4
mm.

They were 6.6 mm and 7.8 mm.

A protrusion of a human ischium was placed over each of the holes in turn.

This person is a healthy man, 46 years old and 173 feet tall.
The pressure sensitive device was placed on the opposite side of the hole to obtain the desired excursions (excurs 1 on), which weighed approximately 84 to 2, and were of average size. The pressure sensitive tool was positioned on a wooden surface so that the pressure, if any, exerted by a person on the tool, ie in the plane opposite the hole, could be measured.

The results obtained are shown in FIG. In only three cases,
The prominence of the human ischial bones did not exert pressure, ie, crash downwards. That is, in a hole of 31.5 man, the deflection (measured by the distance from the surface of the plate to the pressure-sensitive device located in the hole) was 6.6, 7, and 8 mm.

Also, the deviation was 7.8 mm with a hole of 39.0 mm. Thus, with such hole diameter and offset combinations, no downward impingement occurred.

Cavities of such dimensions and smaller diameters would not impinge downward on the ischial prominence of the human subjects used in this example.

In a series of related tests, cavities supporting the human body in various positions, such as the torso in a sitting position, the larger trochanter in a lateral position, and the sacrum and scapula in a supine, crouching position The dimensions were determined.

Such testing provides guidance as to the cavity size required to prevent under-impingement in the clinical support system of the present invention. The results obtained differed depending on the location of the human body.

Example ■ Using a method similar to that described in Example I, except that the holes were square holes, a series of tests were conducted to determine the effect of cavity geometry on the pressure exerted by the ischial tuberosity. In all tests, the sheet or deflection thickness was 8
It was mm. The holes were arranged in an anterior/posterior direction and ranged in width from 18 to 34 mm and length from 20 to 100 mm. The results obtained are shown in FIG. 32m of capillaries
A pressure threshold of m is also shown in this figure.

Example ■ Example ■ was repeated using laterally aligned holes. The results obtained are shown in FIG.

The results of Example 3 show that when the long axis of the hole is aligned in the anterior/posterior direction, the width of 20 to 36 mm is 18 to 34 mm.
We show that only short cavity lengths of mm provide pressures below the capillary pressure threshold.

In contrast, the results of Example 2 show that very long cavities are acceptable.

EXAMPLE■ The pressure exerted by a man lying in a supine position on a pine tress of the type used in hospitals and a synthetic fiber layer on top of this pine tress is shown on the pine tress and the fibrous layer to illustrate the pressure distribution on the patient. Measurements were taken at multiple locations on both.

The results obtained are shown in FIG. 3 High pressures exerted by humans
The three areas, in descending order, were the buttocks, shoulders and head. Using a synthetic fiber layer on the pine tress substantially reduced the pressure on the three areas mentioned above. This reduction is approximately 60 in the shoulder area
%, the pressure was still approximately above the capillary threshold at all three locations.

Example V Recovery of normal (pre-test) skin temperature of human buttocks after various periods in a sitting position was monitored by a thermographic camera. This person is 46 years old and 173 cm tall.
He was a healthy man of average build, about 84cm in weight. The person sits on the singing cushion or on the pine stress system of the present invention operating at a cycle time of 10 minutes for various periods of time and then uses an Amega Infrared Thermography Camera Model 870 for a period of time until the skin temperature returns to normal. The images were monitored using image analysis.

The results obtained are shown in Figure 1O. Since skin temperature is directly proportional to blood flow within the skin, the return of skin temperature to normal values is an indicator of the state of blood circulation within the skin.

The results show that recovery time increases exponentially with the length of the sitting period. Furthermore, the results show that recovery from sitting on the pinerest system of the present invention for 300 minutes is almost as fast as that from sitting on the singing cushion for 5 minutes and than from sitting on the cushion for 7 minutes. It shows that it is quite good. Data regression curves for cushions of 3 and 5 minutes and for the pine tress system of the present invention tend to converge at about 6 minutes, while data regression curves for longer duration cushions indicate a substantially longer recovery period. This is noteworthy.

For optimal operation, the time for recovery to normal blood circulation during the pressure relief phase over the deflated cavity in the pinerest system of the invention should be compatible with the pressure period phase over the inflated cavity. This result indicates that a suitable cycle frequency for the pinerest system of the present invention is about 10 minutes when used in a sitting position by the person described above.

Example ■ Recovery of skin temperature in the sacral region of humans after 2 hours in supine position was monitored by infrared thermography. This person is 46 years old, 1.73 cm tall, and weighs about 84 kg. and a healthy man of average build.

The person was placed in a supine position on a standard hospital bed or on the mattress system of the present invention operating at a cycle time of 10 minutes. After 2 hours on the bed or pinerest, the person was turned onto his right side and the sacrum was immediately monitored using the thermographic camera of Example V. The change in average temperature over time of this person relative to the control temperature was measured. The results obtained are shown in FIG.

The temperature response after 2 hours on the hospital bed indicates skin irritation as indicated by a constant increase in temperature relative to the control. This skin inflammation is characterized by a reddening of the skin and an increase in temperature directly after a period of rest over the pressure points. In contrast, after 2 hours on the pine tress system of the present invention, the temperature response approached normal temperature after 15 minutes without inducing skin irritation.

Features and aspects of the invention are as follows: 1. comprises a plurality of discrete cavities formed from a flexible material in a single layer of selected dimensions and shapes; Sufficiently impermeable to the fluid contained in the cavity so that it can be alternately and repeatedly inflated and deflated; sized and shaped and with spacing between cavities such that the distance between centers is less than the human two-point discrimination threshold; and capable of carrying the weight of a human being without impinging on either or between the bulging cavities. A support system that can be supported.

2. The support system of 1 above, where the deflated cavity exerts a pressure on the body lower than the human internal capillary threshold when the support system supports a human body.

3. The cavity is placed on the support system 2.5 & has a spherical surface with a diameter of 2.67 cm and is of such shape and dimensions that the spherical surface does not impinge under the support. Support system of l above.

4. The support system according to any one of 1 to 3 above, in which the cavity can be independently inflated and deflated.

5. The support system according to any one of 1 to 4 above, wherein the fluid is a fluorocarbon or a mixture of fluorocarbons.

6. The support system of any one of 1 to 4 above, wherein the fluid is an environmentally acceptable alternative to fluorocarbons.

7. (a) comprising in a single layer a plurality of discrete cavities formed from a flexible material of selected dimensions and shapes; provided that the material is such that each cavity can be inflated and deflated alternately and repeatedly; substantially impermeable to fluids contained in the cavity; the cavity is at least 1/2 the width and length of the support system;
The distance between the centers of adjacent bulging cavities is 2
A support system sized and shaped and having a spacing between cavities such that it is narrower than a point discrimination threshold: and capable of supporting the weight of a human being without impinging on any of the bulging cavities or between them. and (b) means for inflating and deflating the cavity.

8. The support system of 7 above, in which when the clinical support system supports the human body, the deflated cavity applies pressure to the body that is lower than the human internal capillary threshold.

9. In 2.5, the cavity is placed on a support system? 8. The support system according to claim 7, having a spherical surface with a diameter of 2.67 cm and having a shape and dimensions such that the spherical surface does not impinge on the bottom of the support.

10. The support system according to any one of 7 to 9 above, in which the cavity can be independently inflated and deflated.

11. The support system according to any one of 7 to 1O above, wherein the fluid is a liquid that can evaporate and inflate the cavity.

12. The support system of 11 above, wherein the means for inflating and deflating the cavity is heating and cooling means.

13. The support system according to any one of 7 to IO above, wherein the fluid is a gas.

14. The support system according to any one of 7 to 1O above, wherein the fluid is a liquid.

15. The support system of 13 above, wherein the means for inflating the cavity is a compressor.

16. The support system according to 14 above, wherein the means for inflating and deflating the cavity is hydraulic means.

17. The support system according to claim 12, which comprises electrothermal or thermoelectric means and is suitable for the liquid to be evaporated by such electrothermal or thermoelectric means.

18. The support system according to any one of 7 to 17 above, which is configured to eliminate complete collapse of the cavities when each cavity is deflated.

19. The support system according to 18 above, wherein the means for inflating the cavities is adjusted so that when one cavity is inflated, the adjacent cavity is deflated.

20. 14 above, in which the liquid is suitable for both heating and cooling.
support system.

21. The support system of 14 above, wherein the liquid is suitable for either heating or cooling.

22. Any one of 7 to 21 above, wherein the cavity is suitable for inflating and deflating in a cycle time of less than 2 hours.
two support systems.

23. The support system according to any one of 7 to 22 above, wherein the distance between adjacent bulged cavities is 30 mm or less.

24. The support system of any one of 7 to 23 above, wherein the cavity is inflated and deflated using simulated wave motion across the support system.

25. Inflating and deflating the cavity using simulated peristalsis across the support system 7-23 above.
Any one support system.

26. The support system of any one of claims 1 to 25, wherein the means for inflating and deflating the cavity has a cycle time that promotes restoration of normal capillary circulation in the human skin while the cavity is deflated.

27. (a) a single layer comprising a plurality of discrete cavities formed from a flexible material of selected size and shape; provided that the material is such that each cavity can be inflated and deflated alternately and repeatedly; The cavity is sufficiently impermeable to the fluid contained in the cavity: the cavity is such that the distance between the centers of adjacent bulging cavities in at least one of the width and length of the support system is within the range of human two-point discrimination. a support system dimensioned and shaped and having inter-cavity spacing such that it is narrower than the threshold; and capable of supporting the weight of a human being without impinging on any or between the bulging cavities; A support system comprising in sequence: b) means for inflating and deflating the cavity; (c) a layer of cushioning material; and (d) a layer of material having a high coefficient of friction.

28. The support system of 27 above, wherein when the support system supports the human body, the deflated cavity exerts a pressure on the body that is lower than the internal capillary threshold of the human being.

29. 2,5 kj where the cavity is placed on a support system? of,
28. The support system of claim 27, wherein the spherical surface has a diameter of 2.67 cm and is shaped and dimensioned such that the spherical surface does not impinge on the bottom of the support.

30. 2 above, wherein the woven fabric layer is located on the flexible material layer, and the woven fabric layer is between the moisture absorbing layer and the flexible material layer.
The support system of any one of 7 to 29.

31, 27 to 30 above, wherein the woven fabric layer is a removable woven fabric layer
Any one support system.

32. The above 27--wherein the moisture absorbing layer is a microporous film layer.
Any one of 31 support systems.

33. The support layer according to any one of 27 to 32 above, wherein the moisture absorbing layer is a disposable layer.

34. The support system of any one of 27 to 33 above, wherein the fluid is a fluorocarbon or a mixture of fluorocarbons.

35. The support system of any one of 27-33 above, wherein the fluid is an environmentally acceptable alternative to fluorocarbon.

36. The support system according to any one of 27 to 33 above, wherein the fluid is a gas.

37. The support system according to any one of 27 to 33 above, wherein the fluid is a liquid.

38. The support system of any one of 7 to 25 above, wherein the means for inflating and deflating the cavity has a cycle time that promotes restoration of normal capillary circulation in the human skin while the cavity is deflated.

39, capable of being alternately inflated and deflated, and formed from a flexible, impermeable thermoplastic material, and having a range of 0 to 50
A cavity containing an inert liquid having a boiling point in the range of °C and further having means for heating and/or cooling the liquid.

40. 39 above, wherein the fluid is a mixture of fluorocarbons
cavity.

41. The cavity of 39 above, wherein the fluid is an environmentally acceptable fluorocarbon substitute.

42, above 4, wherein the fluid has a boiling point in the range of 10 to 40 °C
0 or 41 cavities.

43. The cavity of 42 above, in which the fluid has a boiling point of 20-34°C.

[Brief explanation of the drawing]

Figure 1 schematically shows part of a row of cavities of a clinical support system, all shown in an inflated state; Figure 2 shows a support system as shown in Figure 1, some of which are shown in a deflated state. and FIG. 11 is a graph of temperature versus recovery time as measured in Example V; and FIG. 2 is a graph of temperature response versus time. FIG. 3 schematically shows an embodiment of the support system of the invention; FIG. 4 is a computer simulation of the cavity; FIG. 5 is a computer simulation of the cavity obtained in Example I. It is a histogram of the data; 6th r! ! J is the graph of the data obtained in Example 7.
The figures are graphs of the data obtained in Example 2; Figure 8 is a graph of the pressure profile as measured in Example 2; Figures 9A and 9B are ray fleas (mm1) with long bulging tubular cavities; Japan G, 5 FIG, 7 Kunicho Jinjin Chucho FIG, 8

Claims (1)

Claims: 1. A single layer comprising a plurality of discrete cavities formed from a flexible material of selected size and shape; provided that the material is such that each cavity alternately and repeatedly inflates and deflates. the cavity is sufficiently impermeable to the fluids contained in the cavity so as to allow water to flow through the cavity; being sized and shaped and having inter-cavity spacing such that it is narrower than the human two-point discrimination threshold; and capable of supporting the weight of a human being without impinging on either or between the bulging cavities; , support system. 2. (a) comprising in a single layer a plurality of discrete cavities formed from a flexible material of selected dimensions and shapes; provided that the material is such that each cavity can be inflated and deflated alternately and repeatedly; The cavity is sufficiently impermeable to fluids contained in the support system; the cavity is such that the distance between the centers of adjacent bulging cavities in at least one of the width and length of the support system is equal to or less than two human points. a support system sized and shaped and having a spacing between the cavities narrower than the identification threshold; and capable of supporting the weight of a human being without impinging on any or between the bulging cavities; and (b) means for inflating and deflating the cavity. 3. (a) comprising in a single layer a plurality of discrete cavities formed from a flexible material of selected dimensions and shapes; provided that the material is such that each cavity can be inflated and deflated alternately and repeatedly; substantially impermeable to fluids contained in the cavity; the cavity is at least 1/2 the width and length of the support system;
The distance between the centers of adjacent bulging cavities is 2
a support system sized and shaped and having a spacing between cavities such that it is narrower than a point discrimination threshold; and capable of supporting the weight of a human being without impinging on any or between the bulging cavities; (b) means for inflating and deflating the cavity; (c) a layer of cushioning material; and (d) a layer of material having a high coefficient of friction. 4. Can be alternately inflated and deflated, and is made of flexible impermeable thermoplastic material and temperature range from 0 to 50℃
a cavity containing an inert liquid having a boiling point in the range of and further having means for heating and/or cooling the liquid.