Patent Application
20120116251
The present invention relates to pressure sensors. More particularly, embodiments described herein relate to medical aids for prevention of pressure-wounds such as decubitus ulcers or bedsores.
Pressure-wounds such as decubitus ulcers, which are commonly known as pressure ulcers or bedsores, are lesions developed when a localized area of soft tissue is compressed between a bony prominence and an external surface for a prolonged period of time.
Pressure ulcers may appear in various parts of the body, and their development is affected by a combination of factors such as unrelieved pressure, friction, shearing forces, humidity and temperature.
Currently, about 10%-15% of hospitalized patients are estimated to have bedsores at any one time (Medicare website 2009). However, it is not only hospitalized patients who suffer from pressure-wounds: for example, people confined to wheelchairs are prone to suffer from pressure-wounds, especially in their pelvis, lower back and ankles. Although easily prevented and completely treatable if found early, bedsores are painful, and treatment is both difficult and expensive. In many cases bedsores can prove fatal—even under the auspices of medical care.
The most effective way of dealing with pressure-wounds is to prevent them. Existing preventive solutions are either passive (e.g. various types of cushioning) or active, including a range of dynamic mattresses that alternate the inflation/deflation of air cells. Pressure relief mattresses however tend to re-distribute pressure also from locations where there was no need to relieve pressure thereby needlessly creating higher pressure in sensitive areas. Moreover, such mattresses are typically designed for patients lying down in hospital beds, and hardly answer the needs of individuals who spend considerable amounts of time sitting up, confined to a wheelchair or the like.
The most common preventive approach is keeping a strict care routine of relieving pressure off sensitive body areas of a patient every 2-3 hours. This can be done with patients under strict medical care. As well as being a difficult, labor intensive and costly task, such a care routine does not meet the needs of independent individuals who do not require ongoing supervision of a caretaker, such as paraplegics who use a wheelchair for mobility.
The need remains, therefore, for a reliable, cost effective system and method for preventing the development of pressure-wounds. Embodiments described hereinbelow address this need.
Embodiments described herein disclose a pressure detection mat comprising a plurality of sensors configured to be placed between a subject and a platform and to couple with a pressure-wound prevention system.
Optionally, the pressure detection mat comprises at least one layer of an insulating material sandwiched between a first conductive layer and a second conductive layer. Optionally, the pressure detection mat further comprises at least one substrate layer. Optionally, at least one of the conductive layers are sandwiched between substrate layers.
Optionally, at least one of the conductive layers comprises parallel strips of conductive material. Optionally, the parallel strips of the first conductive layer and the parallel strips of the second conductive layers overlap at a plurality of intersections. Optionally, the parallel strips of the first conductive layer are arranged orthogonally to the parallel strips of the second conductive layer. Optionally, the intersections form capacitance sensors, resistance sensors or impedance sensors.
Optionally, the pressure detection mat further comprises attachment straps. Optionally, the pressure detection mat further comprises at least one humidity-detection sensor, or at least one temperature detection sensor.
Embodiments described herein further disclose a system configured to prevent the creation of pressure-wounds in a subject resting upon a platform, comprising at least one pressure detection mat, a driving unit configured to supply electrical potential to the pressure detection sensors comprising the pressure-detection mat, a control unit configured to control the driving unit and receive data from the sensors, a processor configured to interpret and analyze the data, and at least one display configured to present the data.
In the system, the pressure detection mat is optionally integral to a platform. Optionally, the platform is selected from a group consisting of mattresses, beds, chairs, stools, sofas, wheelchairs, rocking chairs, chaise longue, banquets, bean bags, ottomans, benches and poufs.
Optionally, the system further comprises at least one storage unit configured to store the data from the control unit and the processor. Optionally, the storage unit is mobile and configured to be integrated with a variety of pressure-detection devices. Optionally, the display is selected from a group comprising computer screens, laptops, Personal Digital Assistants, cellular phone screens, printed sheets, integrated Liquid Crystal Display screens, Thin Film Transistors (TFTs), touch screens and combinations thereof. Optionally, the processor uses configurable parameters to analyze the data.
Optionally, the system further comprises at least one sensor configured to monitor moisture. Optionally, the system further comprises at least one sensor configured to monitor temperature. Optionally, the system further comprises at least one sensor configured to detect contact between the subject and the platform. Optionally, the system is further configured to prevent a subject from falling off the platform.
Optionally, the system further comprises a unit configured to send data as to the system's whereabouts. Optionally, the system is further used to monitor the care routine of the subject. Optionally, the system comprises a plurality of pressure detection mats in communication with at least one common control center. Optionally, the system is used as a data harvesting research tool.
Embodiments further teach a method for preventing the development of pressure-wounds comprising providing at least one pressure detection mat comprising a plurality of sensors configured to detect pressure, supplying electrical potential to the sensors, receiving data from the sensors, interpreting and analyzing the data, and providing an output based upon the data. Optionally, the method further comprises storing the data in at least one data storage unit.
For a better understanding of the invention and to show how it may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings.
With specific reference now to the drawing in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention; the description taken with the drawing making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.
In the accompanying drawings,
a shows the main components of a general embodiment of a pressure-wound prevention system;
b shows a extended pressure-wound prevention system including a plurality of pressure-wound prevention sub-systems of different kinds;
a shows a cross section of an embodiment of a single sensor; and
b-e show various isometric projections of embodiments of a pressure-detection sheet;
a-b show a top view and a section through view of a further embodiment of a pressure detection sheet;
a-d show various representations of how pressure data may be displayed on a screen of an embodiment of display system; and
Embodiments of the pressure detection system and method described hereinbelow, are directed towards preventing pressure-wounds from developing in a subject. The embodiments generally provide a caretaker with indications of pressure distribution and ongoing, accumulated pressure exerted upon body parts of a subject, which may result in the creation or progression of a bedsore. A caretaker may then take appropriate action, such as to move the subject or change his cushioning in a way that relieves pressure upon the effected body part. Embodiments of the system may also be used for ongoing analysis and recording of a subject's care routine.
It will be appreciated that embodiments of the pressure-detection system allow a caretaker to move the patient only when it is needed. Furthermore, attention may be targeted towards the pressured part of the body specifically, which may be repositioned or cushioned as required. It is further noted that embodiments of such a system may further assist in monitoring a subject's care routine and his caretaker's performance.
Various embodiments of the system and method for preventing pressure-wounds are presented hereinbelow. Typically, they utilize pressure-detection elements to determine which areas of a subject's body are at risk of developing pressure ulcers. One of these elements could be a pressure-detection sensing mat, configured to couple with a pressure-wound prevention system as outlined below.
Reference is now made to the block diagram of
Measurement readings from the multiple sensors of the pressure-detection mat may be transmitted to a processor 150. Data transmission may be wireless or via data cables according to requirements. The processor 150 may be configured to interpret impedance values and to analyze the data to determine which sensors had pressure applied to them. The interpretation may be performed by consulting with a lookup table which maps impedance values at a given frequency to pressure values, typically in units of millimeters of mercury, as commonly used in medical settings, although other pressure units such as pascals, atmospheres, pounds per square inch or the like may be preferred as suit requirements. The values in such a lookup table will typically differ from one mat to another, and may need to be calibrated automatically or manually, possibly during manufacture or upon initial usage of the mat. It will be appreciated that impedance measurements are effected by a number of properties of the sensors such as resistance, capacitance and inductance, any of which may indicate pressure according to the configuration of the sensing mat.
Other embodiments of the pressure-wound prevention system can be designed for scale and stress, aiming to monitor the accumulated pressure on a plurality of subjects. Such embodiments may include a plurality of pressure-detection mats connected to one or more drivers and control units. Power may be supplied from a plurality of sources, multiple processors may be used for calculation and analysis of the data, which may be stored in a plurality of data storage units.
Reference is now made to
Alternatively, the plurality of pressure-wound prevention sub-systems 100a-e may be located remotely from one another for example each in an individual home, and the remote control center 500 may be a manned monitoring station for the purpose. In such systems, a data communication line may be provided via a cellular network, connections to the internet or the like.
It is further noted that a single pressure-wound prevention system may include multiple pressure detection mats, for example and without limitation two mats located on a seat of a chair and on a back of a chair.
The remote control center 500 typically includes a data storage unit 560 for storing data from the sub-systems 100a-e and a display unit 570 for presenting the data as required.
It will appreciated that the control center 500 may additionally provide processing and driving functionality for controlling multiple sub-systems. Optionally each pressure-wound prevention sub-system 100a-e may have its own dedicated monitor 170 for processing, storing and displaying data locally.
Pressure Sensing Mat for Use with Pressure-Wound Prevention Systems
Embodiments of a pressure sensing mat are disclosed. The sensing mat may be placed between a seat of a chair or a mattress of a hospital bed and the body of a seated subject. The sensing mat is typically used to monitor the pressure exerted upon the subject in a sitting or lying position. The output of the pressure sensing mat may be used to indicate the risk of pressure-wound development.
Reference is now made to
Reference is now made to
A capacitance sensor is based on the capacitance between the sections of the conducting strips overlapping at each “intersection” of a vertical conductive strip with a horizontal conductive strip. These capacitance sensors are configured such that pressing anywhere on their surface changes the spacing between the two conductive layers, and consequently the capacitance of the intersection. A driving unit may selectively provide an electric potential to the vertical strip and the electrical potential may be monitored on the horizontal strip such that the capacitance sensor of the overlapping section may be determined.
It is noted that by providing an oscillating electric potential across each sensor and monitoring the alternating current produced thereby, the impedance of the intersection may be calculated and the capacitance of the intersection determined. The alternating current varies with the potential across a capacitor according to the formula:
Iac=2πfCVac
where Iac is the root mean squared value of the alternating current, Vac is the root mean squared value of the oscillating potential across the capacitor, f is the frequency of the oscillating potential and C is the capacitance of the capacitor.
Thus where the values of Vac and Iac are known at a known frequency, the capacitance of a sensor may be calculated. Accordingly, where the mechanical properties of the sensor are known, the pressure applied upon the sensor may be deduced.
Preferably a capacitance sensor will retain its functionality even if it is fully pressed continuously for long periods such as or even longer than 30 days and keep its characteristics for periods over the lifetime of the sensing mat which is typically more than a year. Notably, the sensor characteristics should preferably be consistent between two separate events.
According to some embodiments, the mat may further include additional sensors configured to monitor additional factors, particularly additional factors influencing the development of bedsores, such as temperature, humidity, moisture, or the like. Such additional sensors may be configured to monitor the factors continuously or intermittently as appropriate to detect high risk combinations of factors. Such measurements may be recorded and stored in a database for further analysis.
Optionally, additional sensors may be located apart from the pressure-detection mat. For example, the mat could be integrated into a seat of a chair and a touch sensor could be integrated into a chair's back support.
In preferred embodiments of the pressure-detection mat, the materials are selected such that the conductive layers and insulating layers are flexible. The insulation material may be a compressible typically sponge-like, airy or poriferous material (e.g. foam), allowing for a significant change in density when pressure is applied to it. Materials comprising the sensing mat are typically durable enough to be resistant to normal wear-and-tear of daily use. Furthermore, the sensing mat may be configured so as not to create false pressure readings for example when the mat is folded.
The pressure-detection mat 200, or sensing-mat, may be placed underneath or otherwise integrated with other material layers 240a, 240b such as used in standard bed sheets. It will be appreciated that such additionally materials may confer further properties as may be required for a particular application. Typically, the conductive material of the sensors is wrapped by isolating, washable, water resistant, breathing cover mat, allowing minimum discomfort to the subject resting on the mat.
With reference now to
It will be appreciated that in order to get a stable reading of impedance values from a row of sensors, it is preferable that little or no movement be made by the subject during the taking of readings from the sensors. Accordingly, according to certain embodiments the response time of the sensors and the time taken for readings should be small possibly of the order of tens or hundreds of milliseconds, during which movement of the subject is generally insignificant although other response times may be required as appropriate. It is particularly noted that in applications where the subject is largely immobile, it may be advantageous to use longer reading times.
The pressure-detection mat, or sensing-mat is typically placed on surfaces such as a mattress of a hospital bed, a long term care facility bed, a home bed, a seat or a back of a chair, a couch, a wheelchair, or the like. Embodiments of this system can detect the pressure points formed between a subject resting on one or more pressure-detection mats and the surface upon which the mats rest. Surfaces may be parts of chairs, stools, sofas, wheelchairs, rocking chairs, chaise longue, banquets, bean bags, ottomans, benches and poufs. Pressure mapping data per subject may be aggregated over time in one or more data storage units.
With reference to
The pressure detection mat 5000 may be attached to a surface in such a way that prevents movement of the mat relative to the surface. A feature of the embodiment of the mat 5000 is that the cover mat 5500 may include a coupling mechanism for securing the mat to a seat or a back of a mattress, a bed, a chair, a bench, a sofa, a wheelchair or the like. The coupling mechanism may include for example at least one strap 5200 having an attachment means 5240 configured to secure the straps 5200 to the seat or to each other such that the pressure detection mat is held securely. This may be useful to prevent folding, wrinkling or other movement of the detection mat which may contribute to the creation of shear forces which are known to encourage the formation of external pressure sores. Suitable attachment means include for example, hook-and-eye materials such as Velcro®, buckles, adhesives, buttons, laces or such like as suit requirements.
In still another embodiment, the sensor sheet may be used in a combination with an inflatable mattress optionally having a matching grid of cells. In this embodiment, when pressure exceeds a given threshold, neighboring mattress cells will inflate or deflate to redistribute the pressure. It will be appreciated that such an active solution may reduce the necessity to turn or reposition the patient. Accordingly, in certain embodiments, pressure monitoring and relief may be completely automated.
The number of pressure detection mats may vary according to need. Pressure detection mats are typically integrated to areas of a bed or a sitting apparatus which are designed to hold body parts that are prone to develop pressure-wounds. For example and without limitation, areas of a sitting apparatus may be a chair or a sofa's seats, backs, arms, back rails, restraints, leg rests or the like, which may support body parts such as but not limited to the neck, lower back, ankles or heels.
It will be appreciated that multiple embodiments of the pressure-detection mat may be located on a common sitting apparatus. Multiple embodiments of the pressure detection mat on a common sitting apparatus are demonstrated in
Referring back to
In various embodiments, the pressure-detection mat may further include additional sensors which can be used to detect additional environmental parameters such as temperature, humidity, ambient pressure and the like. More embodiments may further include sensors which are not integrated into the mat, aiming to detect parameters other than pressure, for example and without limitation sensors configured to detect contact between a subject and a platform. Such contact detection sensors may be placed for example and without limitation in the top rail and the cross rail of a back of a chair. Detachment of a subject from the back of the chair may result in the subject falling off the chair altogether. Therefore, information obtained from contact sensors placed in the locations mentioned earlier can be processed and used in determining whether there's danger that a subject is about to fall.
In various embodiments, the data storage unit is mobile, and can be moved along with the patient from one sitting apparatus to another. Mobility of the storage unit helps preserve the pressure history of a patient as he is being moved from one room to another, or from one position to another, for example and without limitation from a hospital chair to a hospital bed or from a wheelchair to a car seat. This feature is particularly useful because moving a subject from a lying position to a sitting position does not necessarily relieve accumulated pressure applied upon all body parts.
It is a further aim of the system and method described herein to enable storage of data collected from multiple subjects in a variety of situations and a plurality of locations. Data storage is typically aggregated in one or more database units. Data storage may serve for statistics collection regarding a particular mat or line of mats, comparison of care settings according to patients' groups (for instance diabetic patients), or for the creation of a research tool designed to provide practical recommendations for turning schedules and standard of care.
A software application is typically used to retrieve data from at least one data storage unit, analyze it for different purposes, and display the analysis results in various formats to a user. The software application may include features such as, but not limited to:
External wounds caused by tissue breakdown may develop into pressure-wounds, over time. Shear forces are a common cause of such tissue breakdown. Software may further be used to analyze data received from at least one pressure detection mat and to determine whether shear forces are exerted upon body parts of a subject. Where a subject rests upon the mat, two adjacent sensors are expected to measure approximately similar pressure levels. If that is not the case, the software may deduce that the subject is sliding upon the sensing mat and shear forces are possibly exerted upon the subject's body, creating tissue breakdown.
Reference is now made to
The display system may be a computer in communication with the data storage unit 160 (
Data analyzed from a pressure detection mat may be presented to at least one of a care-giver, a nurse, a man-monitored station, a friend or family member of the subject, to the subject himself or any relevant party. The display unit used to present data may be, for example and without limitation, one or more of computer screens, laptops, PDAs, cellular phone screens, printed sheets, and integrated LCD screens (e.g. TFT, touch screens).
Displaying data to more than one monitor, for example both to a family member and a hired caretaker of a subject, may assist in verification that the subject is receiving proper care from his caregiver. Displaying data to the subject himself is particularly useful in paraplegic subjects who have partial mobility. For example, a subject paralyzed from the waist down and sitting in a wheelchair may not be able to sense that a pressure-wound is forming on his abdomen. However, using the pressure-wound prevention system, he can receive a notification that accumulated pressure has been detected where his abdomen typically rests. The subject may then lean his hands on the wheelchair's arm rests and lift his abdomen off the wheelchair seat for several seconds, thus relieving pressure off the sensitive area.
Data display may include alarms. Alarms may be vocal, visual, tactile, or the like. Presentation of the alarms may be ‘local’ to the subject himself or ‘remote’ when presented to one or more users typically in charge of a subject's care, such as but not limited to a family member or a nurse at a monitoring station.
The system may further be configured to include components capable of sending data regarding the system's whereabouts, using a global positioning system (GPS) or other tracking technologies as suit requirements. For example, data such as pressure-wound formation alerts may be sent along with the system's location to a manned monitoring station. This capability may be useful, for example, when data is sent to a caretaker in charge of multiple subjects who use wheelchairs for mobility within a hospital, a nursing home or another care environment. This information can assist the caretaker in finding the subject within the care facility he resides in and provide him with proper care.
Reference is now made to
The method commences with providing at least one pressure-detection mat comprising a plurality of pressure-detection sensors 610. The method continues with supplying electrical potential to the sensors 620, collecting data from the sensors 630, interpreting and analyzing the data collected from the sensors 640, providing an output based upon the analyzed data 650, displaying the output to at least one user 660, and optionally storing the data in at least one data storage unit 670.
It will be appreciated that the system as described hereinabove may be particularly useful in care facilities such as, amongst others, acute care facilities, sub-acute care facilities, long term care facilities, home care environments, hospices, hospitals, nursing homes, assisted living facilities and the like. In addition similar systems may be adapted for use in other environments such as hotels, vehicle seats, passenger seats, airplane seats, long-haul flight seats and the like.
The scope of the present invention is defined by the appended claims and includes both combinations and sub combinations of the various features described hereinabove as well as variations and modifications thereof, which would occur to persons skilled in the art upon reading the foregoing description.
In the claims, the word “comprise”, and variations thereof such as “comprises”, “comprising” and the like indicate that the components listed are included, but not generally to the exclusion of other components.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IL2010/000294 | 4/8/2010 | WO | 00 | 1/4/2012 |
| Number | Date | Country | |
|---|---|---|---|
| 61202848 | Apr 2009 | US | |
| 61296967 | Jan 2010 | US | |
| 61304507 | Feb 2010 | US |
