Abstract:
A sensor pad is adapted to be positioned under a mattress of a patient&#39;s bed as part of a monitoring system that provides a signal to a caregiver when the patient rises from the bed can be used for multiple patients. The under-mattress sensor pads can be used for a long period of time as the under-mattress sensor pads includes a relatively stiff material.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 62/232,232, titled “Bed Monitoring Pad,” filed Sep. 24, 2015, the disclosure of which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to a sensor pad, in particular, a pad for detecting when an individual exits a chair or a bed. 
         [0003]    A serious problem encountered by operators of hospitals, nursing homes, retirement centers, and other facilities that care for patients with limited mobility is that patients who leave their beds without assistance may subsequently trip or fall. Patients that are heavily medicated or sedated are particularly susceptible to falls. For these reasons, much consideration has been given to systems for monitoring patients and providing a warning that a patient is rising from or has left his or her bed. 
         [0004]    One type of currently used sensor pad is one that is positionable on a mattress of a bed or seat of a chair. The sensor pad is communicatively coupled to a monitoring device, such as a nurse call system. When pressure on the sensor pad is removed, such as when the patient removes himself or herself from the bed or chair, the sensor pad sends a notification to the monitoring device which provides a notification to the caregiver that the patient is no longer in bed or seated in the chair. 
         [0005]    Currently, most of the sensor pads used in patient beds are placed above the mattress in a patient bed. Because of this positioning, current patient monitoring sensor pads are made of soft materials, that are comfortable to sit or lay on, and are more frequently exposed to fluids, friction, and other situations that may reduce the longevity of the monitoring sensor pads. 
         [0006]    Described below are patient monitoring sensor pads that are robust and made for placement under the mattress of a patient&#39;s bed. 
       SUMMARY 
       [0007]    Disclosed is a patient monitoring pad that can be placed underneath the mattress in a patient&#39;s bed. The patient monitoring sensor pad can be used for multiple patients and over an extended period of time before degradation in the performance of the monitoring pad. 
         [0008]    In one aspect, the bed monitoring pad comprises a flexible first plate with conductive material printed thereon; a flexible second plate with conductive material printed thereon, wherein the first flexible plate and second flexible plate comprise zones of conductivity; a soft sponge layer positioned between the first plate and the second plate, the soft sponge layer including a plurality of elongated openings, wherein each elongated opening extends along an axis, and wherein the axis of each elongated opening is diagonal to a long axis of the sponge layer, and wherein the zone of conductivity of the first plate is configured to make physical and electrical contact with the zone of conductivity of the second plate through the opening in the sponge layer when a patient sits or lies on the bed monitoring pad; and a bottom layer below the second plate, the bottom layer being more rigid than the first and second. 
         [0009]    Other features and advantages should be apparent from the following description of various embodiments, which illustrate, by way of example, the principles of the disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1A  is a schematic of a conventional mattress patient monitoring sensor pad, showing the materials in the pad and how they are arranged. 
           [0011]      FIG. 1B  shows the patient monitoring sensor pad of  FIG. 1A  positioned atop a bed mattress. 
           [0012]      FIG. 2A  is a schematic of a first embodiment of an under-mattress patient monitoring sensor pad, showing the materials in the pad and how they are arranged. 
           [0013]      FIG. 2B  shows the patient monitoring sensor pad of  FIG. 2A  positioned atop a bed frame atop which a mattress is to be positioned. 
           [0014]      FIG. 3  is a schematic of a second embodiment of an under-mattress patient monitoring sensor pad, showing the layers or materials in the pad and how they are arranged. 
           [0015]      FIG. 4  is a schematic of a third embodiment of an under-mattress patient monitoring sensor pad, showing the materials in the pad and how they are arranged. 
           [0016]      FIG. 5  is a schematic of the pattern of openings in a soft sponge layer that could be part of an under-mattress patient monitoring sensor pad. 
           [0017]      FIG. 6  is a schematic of an exemplary pattern of conducting material printed on a plate that could be part of an under-mattress patient monitoring sensor pad. 
           [0018]      FIG. 7  is another schematic of an exemplary pattern of conducting material printed on a plate that could be part of an under-mattress patient monitoring sensor pad. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    A patient monitoring sensor pad that is configured for use under the mattress of a patient&#39;s bed or under the cushion of a patient&#39;s chair is described. The patient monitoring sensor pad is made of robust materials and is configured for use with multiple patients, as well as for a long lifetime. Also described are systems that include such patient monitoring sensor pads, as well as methods of using such patient monitoring sensor pads. 
         [0020]      FIG. 1A  shows a conventional patient monitoring sensor pad  10 .  FIG. 1B  shows the conventional sensor pad  10  positioned atop a bed mattress. The conventional patient monitoring sensor pad  10  is configured for use on top of the mattress or cushion on which a patient lays or sits. Because the conventional patient monitoring sensor pad  10  is designed to be in close contact with a patient who lays atop the mattress, at times only separated by a sheet or thin layer of bedding, the conventional sensor pad  10  is made for patient comfort. What this means is that conventional patient monitoring sensor pads are made to be thin and soft. As a result, conventional patient monitoring sensor pads are flexible and bend easily. Also, the human body and variances in the shape and weight distribution of the body are relied upon for proper indications of the presence or absence of a patient. 
         [0021]    In  FIG. 1A , the conventional patient monitoring sensor pad  10  is shown as having five layers. The top  11  and bottom  15  layers can be for example Polyvinyl chloride (PVC), though any flexible, soft, durable, and water resistant material can be used. Between the top  11  and bottom  15  layers are two contact plates  13  and  12  that have a soft sponge  14  between them. The contact plates  13  and  12  can be hard thin plastic with a metallic or carbon coated layer. 
         [0022]    A conventional patient monitoring sensor pad  10  is in reality not comfortable to lay on, and the conventional sensor pad can move as the patient moves, possibly moving the sensor pad into an undesirable position. Hygiene can also be a concern with conventional patient monitoring sensor pads because of the proximity to the patient and bodily fluids. Being on top of a patient&#39;s mattress or cushion can also expose the sensor pad to other conditions that could reduce the lifetime of the sensor pad. In some hospitals, conventional patient monitoring sensor pads are changed when a new patient occupies a bed because of the hygienic concerns. 
         [0023]      FIG. 2A  also shows a first exemplary embodiment of an under-mattress patient monitoring sensor pad  100 .  FIG. 2B  shows the under-mattress patient monitoring sensor pad  100  positioned atop a bed frame atop which a mattress would be positioned. The bed frame has a plurality of slats or struts that extend across one side rail of the bed frame to the other, opposite side rail of the bed frame. The slats are thus positioned to extend orthogonal (i.e., at a right angle) relative to a long axis of the bed frame. This leaves orthogonal, elongated slots or openings between the slats. The side rails extend parallel to the long axis of the bed frame. As mentioned, in use a bed mattress is positioned atop the bed frame such that the patient monitoring sensor pad  100  is positioned between the slats of the bed frame and the mattress. 
         [0024]    The configuration of the under-mattress patient monitoring sensor pad  100  accommodates the environment beneath a mattress or cushion. The under-mattress patient monitoring sensor pad  100  has more layers than the conventional patient monitoring sensor pad  10 . The outer most layers  111  and  112  of the under-mattress patient monitoring sensor pad  100  can be for example PVC, but these layers  111  and  112  can be made of any flexible, soft, durable, and preferably water resistant material. Immediately above the bottom layer  112  are a hard bottom plastic plate  125  and a heavy and/or rigid sponge or plastic plate  120 . The rigid materials used to make the bottom plastic plate  125  and the heavy/rigid sponge/plastic plate  120  are selected to prevent the slats or strutted frame of a patient bed from causing false alarms or a non-functioning state in the sensor pad. In an embodiment, at least one of the layers below the contact plates is more rigid than either the contact plate(s) or the sponge layer. In an embodiment, a bottom most later of the pad is sufficiently rigid such that it will not deform when a patient of at least 200 pounds lies on the mattress above the pad. Below the top layer  111  and above the heavy/rigid sponge or plastic plate  120  are two contact plates  113  and  115  and a soft sponge layer  114  positioned therebetween. The layer  114  may have openings extending therethrough to permit the contact plates  113  and  115  to contact one another through the openings when a force is applied to the pad, such as when a patient lays on the mattress. The contact plates may be made of a flexible material such that they can at least partially flex or deform and contact one another through the openings in the layer  114 . An electrically conductive material is printed on the contact plates. 
         [0025]      FIG. 3  shows a second exemplary embodiment of an under-mattress patient monitoring sensor pad  200 . Like the under-mattress patient monitoring sensor pad  100  shown in  FIG. 1 , the under-mattress patient monitoring sensor pad  200  has outer most layers  111  and  112  that surround two contact plates  113  and  115  and a soft sponge layer  114 . The soft sponge layer  114  has openings that allow the two contact plates  113  and  115  to come in contact and close a circuit when sufficient pressure is placed on the sensor pad, such as when a patient lays on the mattress. A heavy/rigid sponge or plastic plate  220  separates the bottom layer  112  from the contact plates  113  and  115  and soft sponge layer  114 . 
         [0026]    The under-mattress patient monitoring sensor pad configuration shown in  FIG. 2A  and  FIG. 3  accommodate the environment beneath a mattress or cushion. In an non-limiting example, the patient sits or lays six inches (15 cm) or more above the under-mattress patient monitoring sensor pad, and the mattress or cushion distributes the patient&#39;s weight in a way that is not accomplished by conventional sensor pads. As mentioned above, to prevent false alarms or a non-functioning sensor pad, the bottom portion of the under-mattress patient monitoring sensor pad is made with rigid layers beneath the detection layers (e.g. the detection layers  113 ,  114 ,  115  in  FIG. 2A  and  FIG. 3 ). The rigid layers (such as the bottom-most layers  125 ,  220  and/or  112 ) make a level or flat surface below the detection layers, no matter what the type of support is under the mattress or cushion. 
         [0027]    The configurations for under-mattress patient monitoring sensor pads described above leave the top portion of the sensor pads soft, to be able to react to changes in the weight above the sensor pad. The flexibility in the detection layers (e.g. layers  113 ,  114 ,  115  in  FIG. 2A  and  FIG. 3 ) allows the sensor plates  113  and  115  to contact at the openings in the sponge layer  114  when a patient lays or sits on the mattress or cushion above the sensor pad. 
         [0028]      FIG. 4  shows another embodiment of an under mattress pad  300  that includes an additional hard layer of material between the upper PVC layer  11  and the contact plate  114 . 
         [0029]      FIG. 5  shows an example sponge layer  114  with openings  330 . The sponge layer is a thin substrate of material with the openings  330  therethrough. The openings are elongated slots that extend along an axis. At least some of the openings  330  extend along an axis that is diagonal with respect to a long axis of the sponge layer  114 . In use, the pad is positioned so that the openings are diagonal relative to the slats or struts of the bed. The slats or struts that are used or often used in patient beds to support mattresses are usually orthogonal or at right angles to the long axis of the sponge layer  114 . Positioning the openings  330  diagonally avoids false alarms or sensor pad failure due to the pressure from the slats or struts in the mattress support structure hitting a closed portion of the sponge layer  114  as opposed to an opening  330 . Points in the bottom of the sensor pad in contact with the support frame often experience the most pressure when a patient sits or lays on a mattress in a patient bed. Positioning openings  330  so they are more likely to fall over those points that receive the most pressure increases the likelihood of the sensor plates  113  and  115  touching when a patient is in the bed, to give an accurate bed occupancy signal.  FIGS. 6 and 7  show a sponge layer  114  with its openings  330  overlaid with patterns of conductive material  435  and  535 , which are located on the sensor plates  113  and  115 . 
         [0030]    An under-mattress patient monitoring sensor pad can include circuitry to detect contact between the sensor plates  113  and  115 . Also, circuitry can be included in a under-mattress patient monitoring sensor pad that signals a nurse call system once the absence of contact between the sensor plates is detected, and the patient is standing up or otherwise not laying or sitting on the mattress over the under-mattress patient monitoring sensor pad. 
         [0031]    When using an under-mattress patient monitoring sensor pad, as described herein, the sensor pad should sit beneath the patient&#39;s hips under the mattress. Detection of the patient is best when the under-mattress patient monitoring sensor pad sits under the patient&#39;s hip. However, because patients vary in size and can move about in bed, an under-mattress patient monitoring sensor pad can be large enough to accommodate a wide range of patients. The fact that an under-mattress patient monitoring sensor pad is not subject to questionable hygiene situations as often and can be made of more robust materials allows for an under-mattress patient monitoring sensor pad as described above to be used for multiple patients, as well as for longer periods of time, for example multiple months or a year. 
         [0032]    It should be appreciated that the sensor pad is not limited to use with a bed or bed mattress. The sensor pad can be used in combination with any item that a patient lays on or sits in, including a bed, chair, couch, and the like. In this regards, the size and shape of the sensor pad can vary to suit the item with which it is used. 
         [0033]    Moreover, although described in the context of use with a nursing station, it should be appreciated that the sensor pad can be used in any situation where monitoring of a patient or individual is desired. For example, the sensor pad can be communicatively coupled to a Personal Emergency Alarm System (PERS) for on-site assisted living accommodation to a nurses station or off-site alarm relay via the telephone network or internet to family, friends, caregivers, control centers, or any combination thereof. The sensor pads can also be communicatively coupled with Nursecall Systems in hospitals, nursing homes, and other assisted living facilities. 
         [0034]    While this specification contains many specifics, these should not be construed as limitations on the scope of an invention that is claimed or of what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or a variation of a sub-combination. Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. 
         [0035]    Although embodiments of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, methods of use, embodiments, and combinations thereof are also possible. Therefore the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.