Abstract:
A patient monitor pressure pad having a time sensor and alarm circuit that produces an audible or visible alarm output to alert facility care staff that the effective life of the pressure pad is nearing its end.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/696,001, filed Jul. 1, 2005 (Jul. 1, 2005). 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     THE NAMES OR PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to apparatus for monitoring patient movement, and more particularly to pressure pad for use on a chair, bed, or other surface typically occupied by a patient or resident and having an operably connected alarm system for alerting staff when the patient or resident has moved outside a defined area. Even more particularly, the present invention relates to a patient monitoring pressure pad having a time sensor and alarm that alerts hospital or residential care staff that the effective life of the pressure pad is nearing its end. 
     2. Discussion of Related Art including information disclosed under 37 CFR §§1.97, 1.98 
     Residential care facilities, particularly long-term residential care nursing facilities, must provide a considerable measure of protection to residents who may be impaired in their ability to care for themselves or to exercise sound judgment. Inherent in such care is the need to routinely confine residents to beds, chairs, showers, or other defined spaces or support apparatus, or alternatively to monitor patients and residents to ensure that the same do not wander into unsafe circumstances or outside the watchful care of the staff of the hospital or residential care facility. Accordingly, it is known to provide bed, chair, shower, and room occupancy monitoring systems to alert staff or attendants of inappropriate patient movement or mishaps. 
     For example, U.S. Pat. No. 5,410,297 to Joseph teaches a bed monitoring system including a capacitive sensor pad for placement under a patient. The pad comprises a foam plastic pad and heavy aluminum foil plates laminated on opposite sides of the foam. The plates are then adhesively bonded to the inner surfaces of an outer cover. The capacitor of the pad is connected in circuit with an oscillator and produces a frequency-related output. A ripple counter establishes a frequency-related output proportional to the capacitance. A microprocessor reads the counter output and samples are averaged to establish a reference base and the true weight affect of the patient on the sensing pad. Other factors which might effect the signal are readily attended to by programmed compensation. Each subsequent sample is averaged and compared with the reference base. If within a permitted range, the latest and current signal is averaged with the reference base and establishes a new base, and continuously tracks changes in the sensing system. A selected change in a selected time delay system actuates an alert or alarm system, which requires positive resetting to terminate the alarm system. The system is positively reset to return to normal position monitoring. The system may be set to automatically reset the alarm system after an alarm condition is established and then removed by the continuous tracking of the patient movement. 
     Also illustrative of the art, U.S. Pat. No. 5,654,694 to Newham U.S. Pat. No. 5,654,694 to Newham discloses a mobile patient monitoring system. The system includes a load sensor which detects the presence of a patient on a device and further includes a microprocessor responsive to a resident program. A first circuit connected to the microprocessor and to the sensor automatically activates operation of the microprocessor to a “monitor” mode upon detection by the sensor of the patient&#39;s presence on the device; it maintains operation of the microprocessor for a predetermined time period at least equal to a running time of the program; and it terminates operation of the microprocessor at the expiration of the predetermined time period after detection by the sensor of termination of the patient&#39;s presence on the device prior to expiration of the predetermined time period. A second circuit operates the system in response to commands manually applied to the second circuit to deactivate the system to a “hold/reset” mode after activating of the system to the “monitor” mode. The first circuit will also activate the system to the “monitor” mode after the system has been deactivated to the “hold/reset” mode together with subsequent detection by the sensor of termination of the patient&#39;s presence on the device and resumption of the patient&#39;s presence on the device. Alternatively, the microprocessor is responsive to the manually operable switch in the second circuit to activate the system to the “monitor” mode after the system has been deactivated to the “hold/reset” mode. A third circuit connected to the microprocessor provides an audio alarm upon demand by the microprocessor. 
     Patient monitoring pressure pads have a limited time during which their operation is entirely reliable. Accordingly, it is a common practice to have caregivers physical mark the pad with a date to ensure timely replacement before the operation either becomes unreliable or before total device failure. This system of monitoring the patient monitoring pad is unreliable and calls for specific staff action to remember to initiate, and then initiate, an affirmative act to prevent an important care facility device from becoming ineffective. There thus remains a need for a patient monitor pressure pad that provides care facility staff with an indication that the pad is nearing the end of its useful life. Preferably, the indication would be in the form of an audible alarm, such that care facility staff would be required to replace the pressure pad to eliminate an annoying alarm output. 
     The foregoing patents reflect the current state of the art of which the present inventor is aware. Reference to, and discussion of, these patents is intended to aid in discharging Applicant&#39;s acknowledged duty of candor in disclosing information that may be relevant to the examination of claims to the present invention. However, it is respectfully submitted that none of the above-indicated patents disclose, teach, suggest, show, or otherwise render obvious, either singly or when considered in combination, the invention described and claimed herein. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is a patient monitor pressure pad for use in nursing homes, residential care facilities, hospitals, and other establishments that employ means to monitor the whereabouts of facility patients or residents. The pressure pad improves on prior art devices by providing a internal time sensor and alarm circuit that produces an audible or visible alarm output to alert facility care staff that the effective life of the pressure pad is nearing its end. It thus provides means to prevent use beyond the useful life of the pad and therefore to prevent needless accidents caused by unaccounted for patients or residents. 
     It is therefore an object of the present invention to provide a new and improved patient monitor pressure pad. 
     It is another object of the present invention to provide a new and improved patient monitor pressure pad that provides a conspicuous, perceptible signal that the useful life of the pressure pad is near its end. 
     A further object or feature of the present invention is a new and improved patient monitor pressure pad that alerts care givers with such a signal in either audible or visible form. 
     An even further object of the present invention is to provide a novel patient monitor pressure pad having various means for measuring and counting the useful life of the pressure pad before issuing an alarm signal. 
     Other novel features which are characteristic of the invention, as to organization and method of operation, together with further objects and advantages thereof will be better understood from the following description considered in connection with the accompanying drawings, in which preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration and description only and are not intended as a definition of the limits of the invention. The various features of novelty that characterize the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. The invention does not reside in any one of these features taken alone, but rather in the particular combination of all of its structures for the functions specified. 
     There has thus been broadly outlined the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form additional subject matter of the claims appended hereto. Those skilled in the art will appreciate that the conception upon which this disclosure is based readily may be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The invention will be better understood and the objects and advantages of the invention will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
         FIG. 1  is a circuit diagram showing a first preferred embodiment of a circuit for providing a “timed” patient monitor pad, viz, a patient monitor pressure pad having a timing circuit that sends a signal to induce an alarm output to alert persons that the useful and effective life of the pressure pad is nearing its end and should be replaced to ensure reliable performance; 
         FIG. 2  is a second preferred embodiment of a circuit for the inventive apparatus; 
         FIG. 3  is yet another, third embodiment, of the circuit for the inventive apparatus; 
         FIG. 4  is still another, fourth embodiment, of the circuit for the inventive apparatus; 
         FIG. 5  shows a fifth preferred embodiment of a circuit for the inventive apparatus; and 
         FIG. 6  shows a sixth and final preferred embodiment for the inventive “timed” patient monitoring pressure pad. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 through 6 , there is illustrated a number of preferred embodiments of electrical circuits that may be employed to provide new and improved patient monitor pressure pad having a timing circuit to provide an effective date warning alert. The first preferred embodiment of the circuit enabling the alert is shown in  FIG. 1  and is generally denominated  100  therein. This view shows a pressure pad  110  having an internal circuit  120  activated by a switch  130  when a patient sits, lies down on, or otherwise puts pressure on the pad. The circuit includes a memory chip, such as a Microchip Technology Inc. 24AA02/24LC02B 2 Kbit electrically erasable PROM  140 , which is electrically and operatively connected to, and powered by, the pressure pad through a fixed multiple connector  150 . The memory chip automatically updates only as the pad is used and the available useful and or effective life diminishes. This device counts down from a pre-selected number of hours of use (programmed into the EEPROM), and when the number of hours of acceptable use of the pad has been reached, the circuit emits a signal to elicit an alert output. 
       FIG. 2  shows a second preferred embodiment  200  of a circuit employed in the present invention. In this embodiment, in addition to a microprocessor  210  (preferably with EEPROM) that performs the timing operation on a circuit and appropriately updates memory, the circuit also includes a time selection switch  220  (such as a ganged wafer switch) which allows the user to select among different periods of time that must elapse before an alarm is activated. Once again, when the pad  230  is used, switch  240  activates the circuit, and after the pre-determined time has passed, a perceptible alarm  250  is activated via the alarm circuit, which also issues a “pad replace” instruction output  260 . 
       FIG. 3  shows a battery powered embodiment  300  of a circuit for the present invention, which also employs a microprocessor  310 , but includes a battery  320  to power the circuit when electrical switch  330  is triggered by use of the pad  340 . This circuit resembles the circuit shown in  FIG. 2 , but it can be employed as an aftermarket add-on to a pressure pad purchased separately in the market place. It will go into the alarm state when the predetermined time runs out. 
       FIG. 4  is yet another battery powered circuit  400  designed to emit an alarm  410  when the battery  420  runs low, rather than after use of the pad  430 . The circuit must be manually turned on via the pad enable switch  440  to enable alarm operation and turn off with the same switch to conserve battery power. 
     Each of the circuits shown in  FIGS. 3 and 4  will work with numerous patient pressure pad monitors and will go into the alarm condition only when a patient is lying on a bed. Those responsible for replacing worn units will be alerted to a pad that is approaching or has exceeded its useful operational life. 
       FIG. 5  shows a fifth preferred embodiment  500  of a circuit that may be used in the present invention. This circuit employs a battery  510  in conjunction with a dedicated “smart” monitor having a manually operable pad enable switch  520  and provides a dedicated “change pad” alert  530 . Pads employing the circuits shown in each of  FIGS. 4 and 5  must be switched off when not in use to conserve and extend battery life. 
       FIG. 6  is a schematic view showing a sixth preferred embodiment  600  of a circuit employed in the present invention. The foregoing circuits relied on the principle of timing pad use. The circuit of  FIG. 6  is activated with a pad enable switch  610  and when on detects pad wear using a comparator  620 , which measures increased resistance differential in the effective date alarm circuit on signal  630  resulting from component wear. When a threshold differential is reached, a “pad change” output signal  640  is emitted. This is a less reliable means of alerting caregivers to the need to replace a pad. However, it has the advantage of indicating such a need well in advance of a warranty period, particularly in the case of a faulty pad, poor performance, or excessive pad wear over a short period of time. 
     The above disclosure is sufficient to enable one of ordinary skill in the art to practice the invention, and provides the best mode of practicing the invention presently contemplated by the inventor. While there is provided herein a full and complete disclosure of the preferred embodiments of this invention, it is not desired to limit the invention to the exact construction, dimensional relationships, and operation shown and described. Various modifications, alternative constructions, changes and equivalents will readily occur to those skilled in the art and may be employed, as suitable, without departing from the true spirit and scope of the invention. Such changes might involve alternative materials, components, structural arrangements, sizes, shapes, forms, functions, operational features or the like. 
     The above disclosure is sufficient to enable one of ordinary skill in the art to practice the invention, and provides the best mode of practicing the invention presently contemplated by the inventor. While there is provided herein a full and complete disclosure of the preferred embodiments of this invention, it is not desired to limit the invention to the exact construction, dimensional relationships, and operation shown and described. Various modifications, alternative constructions, changes and equivalents will readily occur to those skilled in the art and may be employed, as suitable, without departing from the true spirit and scope of the invention. Such changes might involve alternative materials, components, structural arrangements, sizes, shapes, forms, functions, operational features or the like. 
     Therefore, the above description and illustrations should not be construed as limiting the scope of the invention, which is defined by the appended claims.