Pressure-Sensing Compression Bandage
20230380721 · 2023-11-30
Inventors
Cpc classification
A61B5/1036
HUMAN NECESSITIES
A61F2013/0028
HUMAN NECESSITIES
International classification
A61B5/103
HUMAN NECESSITIES
A61F13/06
HUMAN NECESSITIES
Abstract
A pressure-sensing compression bandage having a plurality of pressure sensors provided to indicate the pressures applied by and/or the pressure gradient created by, the applied bandage at various locations along its length when the bandage is applied to a limb or other extremity.
Claims
1) A pressure-sensing compression bandage, comprising: a) a plurality of bandage layers comprising an elastic layer; the elastic layer comprising a plurality of zones of different elasticities for each zone, wherein a quantity and/or a size of perforations control elasticity of each zone; and b) a plurality of spaced apart pressure sensors disposed on at least one of the bandage layers, wherein wrapping of the pressure-sensing compression bandage about the target object activates one or more pressure sensors to transmit electrical signals to a monitor-controller configured to receive electrical signals; the monitor-controller adapted to display visual pressure readings to a user, thereby providing the user of the monitor-controller ability to use the visual pressure reading and adjust the pressure-sensing compression bandage.
2) The pressure-sensing compression bandage of claim 1, wherein the monitor-controller is a portable device that is configured to communicate with the plurality of pressure sensors by direct connection to electrical leads associated therewith or by wireless communication.
3) The pressure-sensing compression bandage of claim 2, wherein: a) the plurality of pressure sensors are of a type selected from the group consisting of a force-sensitive resistor, a piezoelectric sensor, and a strain gauge; or b) the material used to print the force-sensing resistor components and associated electrical leads is an ink material selected from the group consisting of a conductive polymer, a piezoresistive substance, a dielectric material, silver, silver chloride, and carbon.
4) The pressure-sensing compression bandage of claim 3, wherein the monitor-controller is a programmed mobile device that communicates with the pressure sensors via a wireless communications protocol.
5) The pressure-sensing compression bandage of claim 4, wherein spacing and number of perforations is sequentially increased or decreased to create a distinct stretch of each zone and to control cumulative stretch of the elastic layer.
6) The pressure-sensing compression bandage of claim 5 further comprising the elastic layer, a comfort layer and an outer layer.
7) The pressure-sensing compression bandage of claim 6, wherein one or more of the comfort layer, outer layer and elastic layer are provided with a medically beneficial substance.
8) The pressure-sensing compression bandage of claim 7, wherein: a) the comfort layer's interior surface is provided with an adhesive disposed as a coating, or in a striped or stippled pattern; or b) color codes applied to the outer layer to assist with precise wrapping of the pressure-sensing compression bandage; or c) the comfort layer's interior surface is provided with a therapeutic insert disposed along an interior side of the comfort layer.
9) A pressure-sensing compression bandage, comprising: a) a plurality of bandage layers comprising an elastic layer; the elastic layer comprising a plurality perforations; and b) a plurality of spaced apart pressure sensors disposed on at least one of the bandage layers, wherein wrapping of the pressure-sensing compression bandage about the target object activates one or more pressure sensors to transmit electrical signals to a monitor-controller configured to receive electrical signals; the monitor-controller adapted to display visual pressure readings to a user, thereby providing the user of the monitor-controller ability to use the visual pressure reading and adjust the pressure-sensing compression bandage.
10) The pressure-sensing compression bandage of claim 9, wherein the monitor-controller is a portable device that is configured to communicate with the plurality of pressure sensors by direct connection to electrical leads associated therewith or by wireless communication.
11) The pressure-sensing compression bandage of claim 10, wherein: a) the plurality of pressure sensors are of a type selected from the group consisting of a force-sensitive resistor, a piezoelectric sensor, and a strain gauge; or b) the material used to print the force-sensing resistor components and associated electrical leads is an ink material selected from the group consisting of a conductive polymer, a piezoresistive substance, a dielectric material, silver, silver chloride, and carbon.
12) The pressure-sensing compression bandage of claim 11, wherein the monitor-controller is a programmed mobile device that communicates with the pressure sensors via a wireless communications protocol.
13) The pressure-sensing compression bandage of claim 11; the elastic layer comprising zones of different elasticities for each zone, wherein a quantity and/or a size of the perforations control elasticity of each zone.
14) The pressure-sensing compression bandage of claim 13, wherein spacing and number of perforations is sequentially increased or decreased to create a distinct stretch of each zone and to control cumulative stretch of the elastic layer.
15) The pressure-sensing compression bandage of claim 5 further comprising the elastic layer, a comfort layer and an outer layer.
16) The pressure-sensing compression bandage of claim 15, wherein one or more of the comfort layer, outer layer and elastic layer are provided with a medically beneficial substance.
17) The pressure-sensing compression bandage of claim 16, wherein: a) the comfort layer's interior surface is provided with an adhesive disposed as a coating, or in a striped or stippled pattern; or b) color codes applied to the outer layer to assist with precise wrapping of the pressure-sensing compression bandage; or c) the comfort layer's interior surface is provided with a therapeutic insert disposed along an interior side of the comfort layer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In the following descriptions of the drawings and exemplary embodiments, like reference numerals across the several views refer to identical or equivalent features, and:
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DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
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[0048] As also depicted in
[0049] Exemplary pressure-sensing compression bandage embodiments, such as the pressure-sensing compression bandage 5 of
[0050] The comfort layer of exemplary pressure-sensing compression bandage embodiments may be comprised of, for example, one or combinations of cotton, foam, gel, silicone, elastane (e.g., Lycra®), nylon, spandex, viscose, velour or other suitable and preferably stretchable materials. Exemplary comfort layers may also include on the skin-facing surface thereof a coating, stripe or stippled pattern of an adhesive, such as but not limited to a silicone adhesive, to prevent slippage and thereby allow the associated pressure-sensing compression bandage to be positioned on a limb without malpositioning or movement of the bandage. A silicone or similar adhesive can produce mild adhesion even when placed against macerated skin or exudates from a chronic wound. The applied silicone or other adhesive thickness should be thin enough (e.g., less than 1 mm) so as not to detrimentally affect the overall elasticity of the pressure-sensing compression bandage. As mentioned above, a custom insert may form a localized, intermittent or continuous layer along the interior surface of the comfort layer. As shown in
[0051] The therapeutic layer may carry or be impregnated with various materials such as, but not limited to, silicone and/or a steroid to aid in scar healing, zinc to aid in wound healing, an antimicrobial (e.g., silver) to reduce bacterial load, alginate to assist with fluid absorption, an enzymatic and/or a biologic.
[0052] As described above and illustrated in
[0053] The elastic compression layer of exemplary pressure-sensing compression bandages may be comprised of, for example and without limitation, polyurethane, methylmethacrylate, polyethylene, silicone, polyvinylchloride, polyester, rubber or any other suitably stretchable material. Preferably, but not necessarily, the material forming the elastic layer can be stretched up to 20%, with return of form following stretch.
[0054] The elastic compression layer of exemplary pressure-sensing compression bandages may also contain antimicrobial substances such as zinc oxide or chlorhexidine. When present, chlorhexidine may be bound to the elastic material and used to reduce microbial load when placed in a contaminate field or wound. Chlorhexidine may also be placed in the adhesives that bind the layers of an exemplary pressure-sensing compression bandage so as to impart both bacteriostatic and bactericidal properties to the bandage. Chlorhexidine may also be used in a therapeutic layer in the form of a dressing such as seen in Chlorderm (Entrotech Life Sciences, San Francisco, Calif.).
[0055] One exemplary construction of an elastic layer 45 of a pressure-sensing compression bandage is schematically represented in
[0056] The areas 45a, 45b, 45c of differing elasticity are produced, in this exemplary embodiment, by selectively imparting the elastic material with perforations of different sizes and or number. The spacing and number of perforations may be sequentially increased or decreased to change the amount of stretch in the elastic layer. More perforations will create less tension with even application than the portion of the garment that has less perforations with the equivalent applied tension. For example, in the elastic layer 45 embodiment represented in
[0057] The outer (comfort/application) layer of exemplary pressure-sensing compression bandages may be comprised of, for example and without limitation, one or a combination of elastane (e.g., Lycra®), polyester, nylon, cotton, velour, and carbon, or one or a combination of other suitable materials. As described in more detail below, the outer layer may also include design features that facilitate consistent and reproducible application of the associated pressure-sensing compression bandage.
[0058] A more detailed understanding of the sensor technology of one exemplary pressure-sensing compression bandage may be achieved by referring to the previous disclosure in combination with
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[0060] As can be understood from
[0061] In this particular example, the included pressure sensors are of a force sensing resistor (FSR) type. The resistance of a FSR will vary in accordance with the amount of pressure that is applied to its sensing area. Therefore, a FSR is well-suited to measuring pressures or changes in pressure created by the application of a compression bandage to a limb/extremity. Furthermore, a FSR type sensor may require less than 5V to operate meaning that power requirements are minimized. While this exemplary sensor assembly utilizes a FSR, it should be realized that other types of sensors are also usable, such as but not limited to, sensors of piezoelectric or strain gauge design.
[0062] While FSRs may be obtained in pre-existing form, the FSR sensors used in this particular example are created by printing the components thereof onto a substrate using a conductive polymer or other conductive material in the form of an ink. When used, such an ink may be comprised of, for example, a conductive polymer such as but not limited to polyacetylene, polypyrrole, or polyaniline, a piezoresistive substance, or a dielectric material. A suitable conductive ink may also be comprised of silver, silver chloride, carbon, or other materials that can be screen or laser printed onto substrates. An example of a latter type of such an ink is the C1-1036 silver ink distributed by Engineered Conductive Materials, in Columbus, Ohio.
[0063] The substrate of such an embodiment may be comprised of a variety of materials including but not limited to fabrics and films. In the illustrated exemplary embodiment, the substrate employed is a thin film of polyethylene terephthalate (PET).
[0064] One portion 65 of the provided exemplary sensor assembly circuitry is schematically illustrated in
[0065] The flexible nature of the electrical conduits 80 ensures that there is no increase in resistance and resultant loss of sensitivity at the sensor-circuit interface. The flexible nature of the electrical conduits 80 also eliminates any discomfort that might be imparted to a user if the conduits were comprised of metal wires and, unlike wires, are far less limiting on the elasticity possessed by the associated pressure-sensing compression bandage.
[0066] A cooperating portion 90 of the provided exemplary sensor assembly is schematically illustrated in
[0067] A better understanding of the assembled exemplary sensor assembly described and shown herein may be had by further reference to
[0068] A separator layer 110 is located between the first substrate 75 and the second substrate 100. The separator layer 110 is of a thickness selected to produce an air gap 115 between the active areas 70a, 70b, 70c and corresponding receptor areas 95a, 95b, 95c of each pressure sensor when an associated pressure-sensing compression bandage is in a relaxed (unapplied state). The air gap 115 ensures that the sensors will not produce pressure readings until the associated pressure-sensing compression bandage is wrapped around a limb and applies a pressure to the underlying limb tissue.
[0069] As illustrated in
[0070] Once the various electrical components of the pressure sensors are printed or otherwise applied to the substrates 75, 100, the substrates may be die cut, laser cut, or otherwise trimmed if desired to minimize the size of the sensor assembly 105. It may also be possible to so dimension the substrates 75, 100 prior to applying the electrical components thereto.
[0071] Once the first portion 65 and second portion 90 of the sensor assembly 105 are properly arranged with respect to one another, with the separator layer 110 appropriately positioned therebetween, the adjacent faces of the substrates may be joined to produce a sealed, water-resistant sensor assembly. Joining of the substrates 75, 100 may be accomplished by any know technique, such as but not limited to, heat lamination. The sealed sensor assembly 105 may then be properly positioned on and attached to or embedded in a selected layer (e.g., the comfort layer) of an associated pressure-sensing compression bandage. For example, and without limitation, the sealed sensor assembly 105 may be attached to a layer of a pressure-sensing compression bandage by heat laminating one of the PET substrates 75,100 thereto.
[0072] In some exemplary embodiments of a pressure-sensing compression bandage that employs FSR-type pressure sensors, an area of more rigid material (not shown) may be associated with one or both of the active and receptor areas of the FSR. For example, pieces of rigid material may be bonded to or embedded in the substrate(s) to overlie the active areas and/or receptor areas. When present, the rigid material may assist in transferring the compressive forces generated by application of the associated pressure-sensing compression bandage to the pressure sensors.
[0073] In operation of the exemplary FSR pressure sensors subsequent to attachment to an associated pressure-sensing compression bandage, wrapping of the bandage around a limb/extremity produces a compressive force that causes a compression of the separator material 110 and applies pressure to the pressure sensors. In the case of a pressure-sensing compression bandage that employs FSR-type pressure sensors, this pressure produces contact between the active areas and receptor areas of the FSRs which alters the resistance thereof. Increased pressure will cause a greater portion of the active area to contact the receptor area of a given FSR, which further reduces the resistance of that FSR. Signals indicative of FSR resistance and changes in FSR resistance are received by a monitor-controller that is connected to the sensor assembly and converted into pressure readings, as is described in more detail below in conjunction with
In any exemplary pressure-sensing compression bandage embodiment wherein printing is used in the manufacture of the associated pressure sensors, the thickness of the conductive material (e.g., ink) circuitry may be between, for example, 7-15 m along the circuit length. The electrical resistance associated with such printed conductive circuitry is expected to be extremely low.
[0074] Furthermore, printed conductive material circuitry may be applied to a substrate or directly to a bandage layer in a non-linear orientation/pattern, such that stretching of the associated layer of a pressure-sensing compression bandage will not increase the resistance of the circuit, which could undesirably limit the sensitivity of the pressure sensors. Possible, but non-limiting conductive conduit patterns may include a ladder or grid pattern (i.e., horizontal and vertical printing) or a wavy or zig-zag pattern, to allow for stretch in both the horizontal and vertical directions while still permitting maximal conductive material-to-substrate contact.
[0075] Printed sensor elements may also be of various configuration and orientation. For example, the active and/or receptor areas of an exemplary FSR sensor may have interdigitating fingers, as shown in
[0076] In an alternative embodiment, a FSR sensor may be placed on a dome composed of, for example, polyurethane or an equivalent or similar plastic polymer material, to replace the spacer layer of
[0077] It is typically desirable that a pressure-sensing compression bandage be applied in a spiral with approximately a 50% overlap between turns, as this results in a double layer bandaging at any point, and allows for predicable sustained pressures to be attained. The equation that supports this idea is the Law of Laplace, where P=(TNK)/CW, P represents the sub-bandage pressure (mmHg), T is the bandage tension (kg of Force), C is the circumference of the limb (cm), W is the bandage width (cm), N is the number of layers applied, and K is the constant value of 4620.
[0078] To this end,
[0079] Other outer layer markings or indicators for helping to ensure a consistent overlap is attained when applying an exemplary pressure-sensing compression bandage are also possible. For example, the color coded scheme of
[0080] In use, the sensors will report pressure readings to a monitor-controller, one non-limiting example 155 of which is represented in
[0081] In the particular example depicted in
[0082] A monitor-controller may display readings from pressure sensors in a manner that allows a user to understand the pressure gradient produced by the pressure-sensing compression bandage. For example, as indicated in
[0083] Other exemplary and non-limiting displays associated with a pressure-sensing compression bandage are presented in
[0084] An exemplary monitor-controller may include a microprocessor, memory, communications elements, corresponding programming and/or software, and/or any other components necessary to produce the desired operation and interaction between the monitor-controller and a pressure-sensing compression bandage. Communication between the monitor-controller and a pressure-sensing compression bandage may be wired in nature, or may be wireless in nature such as via Bluetooth® or another suitable wireless communication protocol such as WiFi or Near Field Communications (NFC).
[0085] A mobile device application may also be provided on a mobile device and may communicate with the monitor-controller, accept data from the monitor-controller, or comprise the monitor-controller and its functionality. For example, the sensors on a pressure-sensing compression bandage may communicate in a wired or wireless manner with a mobile device to display a pressure gradient and/or other information (see, e.g.,
[0086] An alerting function may also be provided if the pressure applied by an associated pressure-sensing compression bandage drops below or exceeds some preset ideal pressure or range of pressures. Alerts may be provided to the patient and/or to a health care provider by way of a monitor-controller, mobile device, or another device in communication with the sensors of the pressure-sensing compression bandage.
[0087] An exemplary pressure-sensing compression bandage may report pressures or pressure gradients in real time-even as the pressure-sensing compression bandage is being applied. As represented by
[0088] Exemplary pressure-sensing compression bandages be directed towards quick and efficient monitoring of the pressures under the bandage. An alert may be created when a particular pressure threshold is either exceeded or not met. Alerts can be set to occur, for example, when excessive pressures over 30 mm Hg have existed for greater than two hours, so that such excessive pressure can be alleviated to prevent ischemic conditions. Ranges of acceptable pressures may be customized to an individual to provide maximum comfort while still maintaining graded pressure to help with blood flow up the extremity. This can be observed by the individual or anyone (e.g., a health care provider) who has access to a connected monitor-controller, mobile device and associated application, etc. Pressures can also be tracked, graphed and trended to show how long a given pressure-sensing compression bandage was placed in a beneficial therapeutic range to tailor wound healing rates to an individual. Such information may also be used to gauge how much longer the use of a pressure-sensing compression bandage will be required to improve a particular clinical scenario.
[0089] Data stemming from the widespread use of pressure-sensing compression bandage embodiments and associated programs/software may also be mined to provide data for other clinical scenarios. For example, data obtained from the use of pressure-sensing compression bandage embodiments to treat edema, etc., may be used to provide normative data for other applications, such as, but certainly not limited to, the therapeutic use of compression in the treatment of scarring or burn wounds, the use of compression in athletic apparel (e.g., running apparel), or as an indicator of muscle compliance (e.g., when a muscle is optimally ‘warmed’ up and ready for increased stress) to aid in the prevention of injury.
[0090] The proper compression provided by pressure-sensing compression bandage embodiments will improve edema and facilitate wound healing through the mechanical movement of fluid, resulting in the improvement of the venous pump and lymphatic drainage. This can reduce erythrocyte and leukocyte aggregation, with limitation of capillary plugging and vascular compromise to the soft tissue. In short, pressure-sensing compression bandage embodiments permit optimization of compression application while greatly minimizing or eliminating any potential damage to the compressed tissue due to inappropriate wrapping pressure.
[0091] While somewhat counterintuitive, the use of a pressure-sensing compression bandage to apply pressure to a limb may also improve blood flow. In fact, studies have shown that O.sub.2 partial pressures at the skin increase after compression. Cutaneous blood flow may be reduced, but lowering of edema by compression ultimately increases cutaneous blood flow. Moreover, creating a relative hypoxic state through compression may promote angiogenesis (the forming of blood vessels). It has also been demonstrated that increased fibrinolysis reduces the release of macromolecules into the extravascular space and prevents trapping of mediators important to wound healing.
[0092] Pressure-sensing compression bandage embodiments may also be employed in more invasive interventions to address skin breakdown, infection and ulceration, such as by applying topical medications in conjunction with a pressure-sensing compression bandage. Wound debridement can occur passively through autolytic, chemical, mechanical, surgical, and biologic dressings. Examples of autolytic therapies include collagenase, trypsin and fibrinolytic topicals. Fluid exudate from wounds can be managed with alginates and foams. Moist environments to optimize epithelialization can be improved with application of hydrogels, hydrocolloids, and semipermeable films.
[0093] Wound healing augmentation can occur with the addition of certain growth factors such as platelet-derived growth factor, tissue plasminogen activator, human recombinant epidermal growth factor, and/or granulocyte-macrophage colony-stimulating factor. Increased vascularity has been shown to improve with the use of papain enriched dressings, Stanozolol, and pentoxifyllin. Biological dressings using living cells both from the individual patient or alloplastic materials to provide tissue engineered skin are also becoming more prevalent. Still in the laboratory phase, but possibly not too far from use, are autogenous stem cell enriched dressings. Examples of application of progenitor cells, such as fat stem cells or ASCs with multiple differential capacities, have shown much wound healing improvement in the animal models.
[0094] While the exemplary embodiments described above and illustrated in the drawing figures are directed to a pressure-sensing compression bandage, it is contemplated that the associated technology will be applicable to other devices and treatments. Non-limiting examples of such devices and treatment methodologies include a pressure-sensing cast/splint liner, surgical pressure monitoring, pressure monitoring of intubated patients (e.g., at the occiput of the head or the sacral area), upper extremity compression, post-surgical or plagiocephaly helmets, custom (arm, hand, ankle) sports wraps, prosthetics (e.g., compression of residuum swelling to fit a prosthesis), the treatment of DVT prophylaxis, and in veterinary medicine.
[0095] Of particular note in regard to veterinary medicine is the possible use of pressure-sensing compression bandage technology in equine care and maintenance. For example, a pressure-sensing compression bandage may be placed on the leg or thigh of a horse and information about muscle perfusion can be observed. As resistance in the blood vessels change, the overall pressure under the dressing will change. When blood is shunted away from muscles toward vital organ structure (i.e. brain, kidneys), an increase in blood vessel resistance will result in a drop in overall pressure to the system. This may alert a trainer or other care taker that the risk of muscle injury is high. The return of pressures under the pressure-sensing compression bandage to baseline or actually higher pressures than initially seen will notify the caretaker that the muscle is better perfused and warm enough for increased exercise. A large increase in pressure seen under the pressure-sensing compression bandage may indicate that a muscle is fatigued and detrimental byproducts of anaerobic oxygenation (i.e., lactate, CO.sub.2, etc.) may lead to muscle strain or injury.
[0096] Other contemplated and non-limiting possible uses include the application of a pressure-sensing compression bandage prior to air travel in order to reduce edema as well as to indicate when a user may need to get up and ambulate on long flights. A pressure-sensing compression bandage may also be used under splints to indicate if areas prone to skin breakdown (e.g., the elbow or heel) are experiencing excessive pressure. Pressure changes may also alert a user of excessive pressures and indicate a needed loosening of a splint to prevent pain and discomfort.
[0097] An alternative embodiment of a pressure sensor equipped wearable device 200, 200′ is presented in
[0098] Pressure sensors may be printed, heat laminated, or otherwise applied to the fabric substrate. Sensors may be positioned and arranged to reside over limb areas to be monitored, such as over muscle compartments. For example, there are three muscle compartments in the forearm, and sensors may be located on the fabric substrate to overlie the anterior, posterior and mobile wad of the forearm to independently observe the swelling in each compartment. In the lower leg, sensors may be similarly placed to reside over the anterior and posterior compartment (overlying 4 compartments). It is also possible to locate multiple sensors over a given area of interest, such as over a given muscle compartment.
[0099] Such an embodiment may be left in place while subsequent compressive/elastic dressings are placed. Similarly, such an embodiment may be applied and left in place under a cast or splint.
[0100] Although certain exemplary embodiments are described in detail above, the scope of the invention is not considered limited by such disclosure, and modifications are possible without departing from the spirit of the invention as evidenced by the following claims: