US20110227740A1 - Personnel location and monitoring system and method for enclosed facilities - Google Patents

Abstract

A wireless time-of-flight distance measurement device a motion detector is used at each of a plurality of stations in a wireless network in an enclosed facility to accurately locate a badge-wearing person near the station. The location, badge number and time of detection are transmitted through the network and stored in a computer memory. In a healthcare facility, hand washing detectors are located at some of the stations and caused to energize a hand wash status indicator light on the badge when the wearer has washed his or her hands. The light remains “on” for only a certain length of time, but will be extinguished sooner by a monitor device near each patient when the healthcare worker leaves the vicinity of the patient. These events also are transmitted and stored so that a timed record of each worker's hand washing and visits to patients is created.

Description

FIELD OF THE INVENTION
• This invention relates to the location and monitoring of personnel in an enclosed facility. The invention also relates to the monitoring and control of hand washing by personnel in healthcare facilities and the like.
BACKGROUND OF THE INVENTION
• In many enclosed facilities, it is highly desirable or necessary to locate the positions of various personnel in the facility at various times of the day. This can be useful or necessary for purposes of monitoring the movement of people in secure facilities to make certain that they are not moving into or out of areas without authorization, to provide a record of movement by healthcare workers in hospitals, clinics and the like, and to determine when each person enters or leaves the facility.
• In particular, in hospitals, it is highly desirable to have a stored record of the location of each healthcare worker in the hospital throughout the working day. This can provide valuable records tending to document healthcare treatment of specific patients at specific times, and other valuable information.
• It also is desired to detect and record information indicating the hand wash status of each health-care worker at any time during a work day, as well as the location of the worker when the hand wash status is determined.
• An object of the invention is to provide a stored record of the hand washing activities of each worker in a healthcare facility over a given period of time, to assist in the encouragement of the healthcare workers to wash their hands as frequently as necessary to minimize the spread of infections to patients within the facilities, and to provide records establishing the degree of compliance of each healthcare worker with regulations governing such activities.
• The invention can be used in various facilities such as, but not limited to, a patient care facility, a medical laboratory, a clean-room manufactory, food handling facilities, and any facility otherwise requiring frequent handwashing to retard the distribution of pathogens or other unwanted particles or microorganisms.
• The need for regular, frequent hand washing in healthcare facilities is very important. It has been established that the failure of medical personnel to wash their hands frequently enough leads to many infections of patients in the facilities with diseases that they did not have previously (so-called nosocomial infections). Annually, this causes over 100,000 patient deaths and many serious new infections, often with drug resistant organisms, requiring substantial time, expense and suffering by the patients.
• The cost to hospitals of nosocomial infections is very large. Insurance providers have recently refuse to compensate hospitals for any expenses caused by such infections, as well prohibiting them from passing these costs on to patients. As a result, hospitals suffer severe financial losses from such occurrences.
• As a result, stringent hand washing regulations have been enacted by professional stakeholder organizations and government agencies. These regulations specify, for example, that the hands must be washed both before and after contact with each patient. Although healthcare workers, including doctors, nurses and other personnel, have been warned and instructed in the requirements for hand washing, the degree of compliance often is mediocre to poor. As a result, infection rates attributable to inadequate hand wash compliance in hospitals and other healthcare facilities are unacceptably high.
• Various systems and methods have been proposed in the past for preparing hand wash status records of medical personnel in hospitals and other healthcare facilities. In such proposals, RF (radio-frequency) or other signaling is used in connection with badges worn by healthcare personnel. However, such prior systems are believed to be deficient and are not believed to be in widespread use.
• Another problem in healthcare facilities is the monitoring of the visits of the personnel to specific patients, and the hand wash status of such personnel before, during and after each such visit. Records of such visits and the hand wash status of the healthcare worker would tend to substantiate the level of care and the hand cleanliness of caregivers for the patient at any given time. Such records would be useful in determining insurance claims and in regulatory inquiries.
• A further problem is that the accuracy and reliability of techniques and devices for monitoring hand wash status by healthcare personnel need improvement so that the need for hand washing is indicated reliably and can be used by the healthcare personnel themselves, as well as patients and others, to reliably indicate the need for the hands to be washed.
• Another problem with which this invention is concerned is the location of patients who are moved from their beds to another location in the healthcare facility, and the monitoring of caregiver contact with those patients.
• The present invention provides a system and method which addresses the needs in the field and overcomes the aforementioned problems with known systems.
SUMMARY OF THE INVENTION
• The present invention provides a system which facilitates precise location of individuals in a facility and which correlates the location of such individuals with proximate contact with other individuals (patients in a hospital, other healthcare facilities; skilled nursing facilities, assisted living facilities, nursing homes, for example), and the status of the individual's hand wash compliance status at the time and location of such proximate contact with other individuals. It will be appreciated that while the present system is exemplified with reference principally to a hospital environment, other environments, including but not limited to other healthcare environments, food handling environments, computer clean room and other manufacturing environments, may likewise benefit from implementation of various embodiments of the systems and methods disclosed and described herein.
• Accordingly, it is an object of the present invention to provide an accurate and reliable enclosed facility personnel location system and method, and a healthcare facility personnel location and hand wash monitoring system and method which alleviates or corrects the above-described problems.
• Specifically, it is an object to provide a wireless system and method which is extremely robust and error-free in detecting the whereabouts of personnel, and hand wash status of medical or other personnel, in an enclosed facility.
• It is another object of the invention to provide such a system and method which detects and records when each healthcare worker washes his or her hands, when each such worker comes in close proximity to a patient, and gives to all an indication of the hand wash status of the worker.
• It is another object of the invention to provide a system which records such information automatically as the personnel and patients move within the facility, and provides a stored record which is retrievable and from which compliance records can be prepared, for use in proof of compliance and treatment visits to patients, and other relevant information for such personnel.
• It is a further object to provide such systems and methods which are wireless, relatively simple and low cost, reliable in operation, have very low power requirements and long battery life, and require relatively low maintenance and are largely trouble-free.
• In accordance with the present invention, the foregoing objects are met by the provision of a system and method for locating personnel in an enclosed facility having a plurality of spaced-apart stations, in which an indicator tag or badge is carried by each of the personnel.
• Equipment is provided at each station to determine when each tag is within a predetermined distance from the station, and to record the number of the tag and time of the event.
• This is done, preferably, by transmitting first and second wireless signals between the station and the tag. Preferably, the signals have significantly different transmission velocities. One signal preferably is an electromagnetic signal, such as a RF signal, and the other is, preferably, an ultrasonic signal. The difference in the transmission times of the signals is measured, and when that difference is below a predetermined level, the location and tag number are recorded by sending the information through a network to storage, where it is stored together with the time and date on which the record is stored.
• In accordance with another feature of the invention, the various stations within the facility are associated with one another in a wireless network e.g. a “ZigBee” network, which is very simple and inexpensive to build and maintain. Preferably the data is encrypted for secure transmission. Thus, there is created a useable record for all of the personnel present in the facility over a given time period.
• Other relatively simple wireless local area networks such as Wi-Fi, Bluetooth, etc. can be used instead, if desired or needed.
• When used in a healthcare facility, such as a hospital, each identification tag or badge is worn by an individual associated with and whose name appears on that tag. The tag also bears means such as one or more visible LEDs for indicating to all the hand wash status of the wearer, and, optionally another indicator, such as a vibratory or auditory signal, to tell the wearer when hand washing is needed.
• In at least some of the stations within the facility, hand washing equipment is provided, in addition to the distance detection equipment described above. At each such hand wash station, a hand wash detector is provided to detect and indicate the satisfactory completion of a hand washing operation by the badge-wearer and to transmit this information to the badge and turn on the LED. The LED remains lit for a pre-determined time, during which it is discernable by all to indicate the positive (hands are clean) hand wash status of the wearer.
• The hand wash detector preferably senses vapors on or emanating from the hands of an individual upon application to their hands of an appropriate hand wash composition, or immediately after he or she has washed their hands with a substance containing a an appropriate volatile, detectable compound, such as a chemical taggant, such as alcohol, which may also be bactericidal. However, other hand washing detectors which are known in the art can be used instead, if desired. For example, hand washing may be presumed by monitoring the dispensation at a given hand wash station of an appropriate hand washing agent when a given healthcare worker is in sufficient proximity to such a station.
• In accordance with another feature of the invention, location detectors, preferably of the same general type as those used at the hand wash stations, are mounted near or onto patient beds, and on wheelchairs, gurneys, and other internal hospital transportation and/or patient-supporting devices for detecting the tag of each person who approaches the patient close enough to touch the patient or otherwise transmit pathogens to the patient.
• These monitors are referred to herein as “bed monitors”, (or, alternatively, as “bed stations”) or “transportation monitors”, respectively.
• Thus, when a healthcare worker approaches to within a predetermined distance of a patient located in a bed or on another support, the bed or transportation monitor records the identify of each individual tag that is detected, the identity of the patient and the hand wash status of the worker, and transmits this information through the network to the data storage facilities, where it is stored together with the date and time of the transmission.
• When the patient is transferred from his or her bed to a wheelchair or other conveyance, the information identifying the patient and the bed location stored in the bed monitor is transferred to a similar transportation monitor mounted on the transportation means, which will detect and record close encounters with other personnel. Alternatively, or in addition, as described in further detail below, the patient may be provided with a detector which detects, records and transmits to a central processing unit and database, each healthcare worker that approaches the patient. When used in addition to a bed monitor or transportation monitor, such patient-specific monitors provide confirmatory data and redundancy to the system in the event that, say, a bed monitor is malfunctioning.
• As noted above, preferably, each badge or identity tag worn by personnel in the hospital facility has an indicator LED, such as a green light, which is lit immediately upon the successful completion of a hand washing operation. The LED stays lit for a predetermined length of time, such as ten minutes, at which time the light is extinguished and the wearer must wash his or her hands again in order to relight the LED.
• It usually is required that each healthcare worker wash his or her hands both immediately before and immediately after touching or coming close to any particular patient. Therefore, an additional advantageous feature of the invention is to provide means in each bed monitor and each transportation monitor to hold the green light on, if it is on when first detected, for as long as the healthcare worker remains sufficiently close to the particular patient. Alternatively, or in addition, an LED on the bed monitor may illuminate to reflect the status of a healthcare worker's hand hygiene status while that healthcare worker is attending to the particular patient.
• It also is advantageous to automatically turn the light off as soon as the healthcare worker moves away from that particular patient to go elsewhere, even if the time set for the light to go out (e.g., 10 minutes) has not expired. This will tend to encourage the healthcare worker to wash his or her hands before approaching the next patient. This also may comfort the patient who sees the green light.
• The use of a single indicator light on the identity tag is not essential to the invention, but is preferred as being potentially more acceptable to both patients and healthcare workers than one like those proposed in the past, which shows another light (usually red) when the time after the previous hand washing has expired. Furthermore, the single light limits power usage. Optionally, a vibratory or auditory signal can be used in the tag to remind the worker of the need for hand washing.
• It is believed that, if the indicator works accurately, it will allow the patient to reinforce the requirement of hand washing by the healthcare worker serving the patient, and also will engender respect for and reliance on the indicator system.
• An alternative is to simply leave the green light on until the on time expires, regardless of where the worker goes. Although this is simpler to do, it is less informative to patients and workers.
• An alternative embodiment of the invention uses a motion detector, either in addition to the distance measurement device, or instead of it, to enable the monitor/personnel locator.
• In the bed monitor, the motion detector stops the unit from emitting “pings” unless the motion of a person at the side of a patient support (e.g., bed) is detected. This can help reduce battery drain, and does not depend upon being able to detect a badge within range.
• In the hand wash monitor/locator, the motion detector will start the sending of signals to and receiving of signals from the badge, regardless of whether the badge wearer has turned the unit on. Thus, the person is located, even if he or she does not attempt to wash his or her hands.
• The foregoing and other objects and advantages of the invention will be set forth in or will be apparent from the following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a broken-away perspective view, partially schematic, of an enclosed facility such as a hospital, together with various components of the locating and detection system of the invention.
• FIG. 2 is a front elevation view of a one embodiment of an identity tag worn by personnel in the facility shown inFIG. 1.
• FIG. 3 is a schematic diagram illustrating the use of a monitor at a doorway to detect and record the passage of a person through the doorway.
• FIG. 4 is schematic block diagram of a location unit and a hand wash detector/verification unit constructed in accordance with one embodiment of the invention.
• FIG. 5 is a schematic block diagram of the electrical components of one embodiment of the identity tag for use according to this invention shown inFIG. 2.
• FIG. 6 is a schematic diagram of a network for associating the various monitors and detectors with one another to perform the functions of the invention.
• FIG. 7 is a top plan view, partially broken away, of a motion detector for use in one embodiment of the invention.
• FIG. 8 is a front elevation view of theFIG. 7 motion detector arrangement for use in one embodiment of the invention.
• FIG. 9 is a side elevation view of the motion detector arrangement ofFIG. 7 for use in one embodiment of the invention.
• FIG. 10 is a perspective view of a component of the motion detector element ofFIG. 7 for use according to one embodiment of the invention.
• FIG. 11 provides a process flow diagram showing the steps involved in the operation of one preferred embodiment of the wash station implemented according to this invention.
• FIG. 12 provides a process flow diagram showing the steps involved in the operation of one preferred embodiment of the badge worn by healthcare or other workers implemented according to this invention to document and confirm hand wash compliance.
• FIG. 13 provides a process flow diagram showing the steps involved in the communication between the badge worn by healthcare and other workers and the hand wash station implemented in a preferred embodiment according to this invention, to document and confirm hand wash compliance.
• FIG. 14 provides a process flow diagram showing the steps involved in the communication between the badge worn by healthcare and other workers and the patient bed monitor implemented in a preferred embodiment according to this invention, to document and confirm hand wash compliance.
• FIG. 15 provides a process flow diagram showing the operation of a preferred embodiment of the bed monitor implemented according to this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
• FIG. 1 shows a broken-awayportion10 of an enclosed facility, in this case a hospital, in a preferred embodiment of the invention.
• The hospital is a typical enclosed facility having several stories, each having afloor12,vertical walls14,16 and18 forming ahallway20, and apatient room22 containing apatient bed24.
• In one exemplary embodiment of the invention, it being understood that variations on the specific configurations described herein come within the scope of the invention, in thehallway20 is ahand wash station26 and apersonal computer44 at astation28, with thecomputer44 sitting on a table46, for use in a network or otherwise as described below.
• At thehand wash station26 are twosinks30 and32, twodispensers34 and36 of bactericidal soap, for example, or a waterless hand hygiene composition, such as an alcohol hand rub composition, for use in washing the hands, and a towel dispenser, heated air hand dryer or other hand-dryingapparatus38. Where waterless hand wash agents are provided, it may not be necessary to provide or use a hand drying apparatus. A personnel locator andhand wash detector40 or42 is located closely adjacent eachdispenser34 or36 or both. Alternatively, or in addition, in another embodiment according to the invention, theunits40 and42 may be sensors which record the dispensation of hand wash composition from thedispensers34 or36.
• The term “hand wash station”, as used herein includes not only stations likestation26 shown inFIG. 1, but also other stations which consist of nothing more than a wall-mounted dispenser of alcohol-containing gel, r foam or liquid, such as dispensers sold under the PURELL® trademark and an associated hand wash detector such as40. Such dispensers already are used in this way in many hospitals today. There need not be a wash basin at the site, as long as a suitable hand cleaner dispenser is available there.
• Mounted on or near thepatient bed24 is a personnel locator or “bed monitor”50. In the hallway is awheel chair48 for transporting patients. Thewheel chair48 is representative of gurneys and other such transportation devices as well. Thewheel chair48 has attached to it a personnel locator or “transportation monitor”52, which is basically the same as thebed monitor50.
• Thebed24, thewheelchair48, and tables all are referred to herein as “patient support”-structures on which a patient may sit or lay down.
• The term “transportation monitor” includes monitors for use in transporting patients, both inside and outside of the hospital enclosure, such as in ambulances (ground or airborne), etc.
• The bed monitors need not be mounted on the bed or other patient-supporting surface, and might be mounted to advantage on the ceiling above a bed, or on a wall near the bed, or wherever it best detects identity tags reliably. As discussed below, alternatively, or in addition, the monitor may be associated with the particular patient, as, for example, in a wrist band or necklace, badge or any other apparatus which reliably detects healthcare workers when they are sufficiently proximate the particular patient and which does not cause discomfort to the patient or impede in their receipt of medical attention.
• FIG. 2 shows an identity tag or badge54 which is worn, preferably, by every worker in the hospital, or at least by all of those who will or might come in close proximity to patients in the hospital. In non-hospital environments, similar tags could be worn, for example, by old-age care workers, by food handling workers, or by staff employed to work in clean-room facilities.
• The tag54 includes anindicator light56, preferably a green LED, which is visible to others, as well as the wearer, to indicate the hand wash status of the wearer. In thearea58 is a prominent display of the name of the healthcare worker to whom the tag is assigned.
• The dashedline60 inFIG. 2 schematically represents electronic circuitry and devices shown inFIG. 5 which are located in the tag.
• FIG. 3 is an elevation view showing the location of amonitor72, like thebed monitor50, on theceiling68 near adoorway62 in awall64 with door framing66 and the floor indicated at70. Themonitor72 detects the identity tag54 worn by each person passing through the doorway, and causes the identity tag information and hand wash status to be transmitted through the network and stored.
• The network preferably is an ultra-low power wireless network, such as a “ZigBee” network, which delivers information through a gateway to the central computer system of the hospital or to another data storage device, as it will be described in detail below.
• As noted above, other known networks also can be used satisfactorily to implement the invention.
Personnel Locator and Hand Wash Detector
• FIG. 4 is a schematic diagram showing the electrical and electro-mechanical components of a personnel locator and handwash detector unit40. In a preferred embodiment according to the invention, eachunit40 includes three separate modules: an, optionally, removable and, preferably, rechargeable battery pack or likepower handling module74, such as a lithium battery pack or direct wall power management and conversion system to provide electrical power; apersonnel location unit76, and a handwash detection unit78. It will be appreciated that the following detailed and specific components comprising each of these elements may be modified in layout, detail or other specifics without departing from the essence of the invention disclosed herein. For example, not all elements described are required to be included in a given embodiment or implementation of the invention. Thus, for example,LCD display104 described below, may or may not be part of a given implementation of the invention, or may or may not be included in every installation of thepersonnel location unit76, or handwash detection unit78. Likewise, as will be explained below, a motion detector rather than, or in addition to, a personnel locator, may be included in a particular implementation or location, without departing from the essence of the invention disclosed herein.
• In a preferred embodiment, DC power is delivered from thebattery pack74 to thepersonnel location unit76. Alternatively, if an electrical outlet is at hand, power can be supplied from an ordinary 120 volt AC outlet and an AC/DC adapter. Then the battery serves as a back-up in case of power failure.
• An optionalsolar charging system80 can be provided. Theunit80 is well-known. It uses the over-head electrical lighting and photovoltaic cells to recharge the battery pack and thus minimizes or eliminates the chore of recharging the batteries.
• In a preferred embodiment, thepersonnel locator unit76 comprises amicrocontroller82, which includes a CPU, RAM, ROM, etc. and which is programmed so as to perform the functions to be described below.
• Although many suitable microcontrollers are available, one such unit is sold by Silicon Laboratories, Inc. Austin, Tex., Part No. C8051F9XX.
• Thelocator unit76 also includes a conventionalnetwork transceiver unit84 with anantenna86 for transmitting and receiving electromagnetic signals, such as RF signals, using, for example, the IEEE 802.15.4 protocol used by a ZigBee network. Thetransceiver84 is connected to themicrocontroller82 throughSPI port98.
• Asecond transceiver90 also is provided and connected to themicrocontroller82 throughserial port100 to send and receive electromagnetic signals, such as RF signals, through anantenna92 to and from the badges or tags54 worn by the personnel. In particular implementations, depending on the type of electromagnetic signal used, there may be the need to modifyelements86,84,90 and92, such that, for example, if instead of RF electromagnetic signals, infrared signals (IR) are used, then, in that case, these elements would need to constitute IR LEDs to transmit and IR photodiodes to receive IR signals. Those skilled in the art will appreciate and understand the particular modifications required to these elements to achieve equivalent function to the RF embodiment represented in this example depending on the particular electromagnetic (EM) transmission and reception variations used in a particular implementation of the invention. The first EM, such as RF, signal sent preferably contains a unique signal identifying the station from which it is issued.
• Also provided is anultrasonic pulse generator94 which sends ultrasonic pulses through anacoustic transmitter96 to be received by receiving equipment in the tag or badge54. The ultrasonic generator, for example, may comprise a transducer made by Kobitone Audio Company, P/N 255-400SST12ROX, which generates pulses at a frequency of approximately 40,000 Hertz. However, other frequencies and other transducers can be used instead.
• LED102, preferably colored, is provided to be lit whenever wireless contact has been made with a badge that is within range; that is, one which is within a predetermined, preferably programmable, (depending on the needs of a particular installation and a particular situation of a locator unit76), distance from thelocator unit76.
• LCD display104 is provided in order to display the identifying number assigned to the particular tag or badge which has come into range of the givenlocator unit76. Alternatively, or in addition to detection of the identifying information from a given tag, the system may include a biometric identification system, such as, for example, a retinal scanner, facial recognitions software or a fingerprint reader or the like to provide a means for positive identification of a given person performing a hand wash procedure at a particular location at a particular time.
• Apower management subsystem88 is desirably provided which receives power from thebattery pack74 and delivers a sample of the battery voltage to the microcontroller through anADC port106, for the purpose of detecting low battery conditions.
• Thesubsystem88 also receives a “hand sense” signal overline112 from an ultra low-power sensor, such as aphoto detector110, which serves to turn on thepersonnel locator76 and thehand wash detector78.
Motion Sensor Embodiments
• In further embodiments of the invention, a motion sensor is used at each hand wash station in addition to or instead of a distance measuring device. These embodiments are illustrated in FIGS.4 and7-10 of the drawings.
• The embodiment will be described first as an addition to thebed monitor50, as shown inFIGS. 7-10. The bed monitor50 is shown inFIGS. 7-10 mounted on avertical support frame192 which extends upwardly from the rear of thebed24 to a position above theupraised head portion186 andhorizontal portion188 of the bed. The side rails of the bed are shown at184, and the bed rests on thefloor190 of a hospital or other healthcare facility. Apillow194 is shown inFIG. 8.
• As shown most clearly inFIG. 10, amotion detector sensor180 is mounted on the outside of the housing of themonitor unit50. A horizontal plate or like shielding means182 is attached at a position underneath thesensor180.
• As shown inFIG. 8, theplate182 is dimensioned and shaped so as to form a shield to prevent thesensor180 from sensing the motion of the patient on the bed, and forming detector area limits196 and198 to confine the motion detection function to persons at the sides of thebed24.
• Referring toFIG. 9, preferably, the motion detector has arange200 which does not extend significantly beyond the foot of the bed to thereby avoid detecting the motion of persons merely passing by.
• Referring now toFIG. 4, themotion detector110 is electrically connected to thepower management subsystem88 to turn on the function of sending sonic signals or “pings” when motion is detected. Themicrocontroller82 is programmed to start the sending of pings when it has had no response from a badge for a predetermined number of pings, and has detected no badge within the range of the distance measurement equipment, and also detects no signal from themotion detector110.
• This function is effective to turn off the pinging function when personnel beside the bed have moved out of range of the monitor unit. This tends to save battery power by preventing the ranging signals from being transmitted when healthcare personnel are not present and moving.
• If desired, the motion detector device can be substituted for the distance measuring device of the invention, where it is deemed acceptable, despite the lower accuracy this would entail in determining the distance of the personnel from the motion detector.
• When the motion detector is used, in addition to or instead of the distance measurement device, at a hand wash station, such as theunit40 shown inFIG. 4, theunit76 is turned on by the motion detector instead of thephotosensor110. This means that the badge information and other information are sensed and transmitted at the station through the network for recording, regardless of whether the person attempts to wash his or her hands at the station. This can have the advantage of confirming the location of a given person at a hand wash station at a particular time of day, even though the person does not wash his or her hands.
• Although a variety of types of motion sensors can be used, an IR radiometer type, such as those widely available from Panasonic and others, is believed to be suitable. Although the use of theshield plate182 is shown, the motion detector sensor itself can be adjusted to exclude thebed24 from its field of view, if preferred.
• If the motion detector is used in addition to the distance measuring equipment, themonitor unit76 will respond only to the badge which is within the precise distance measurement of the monitor unit, regardless of motion detected beyond that range. In a preferred embodiment according to this invention, however, it is the logic circuitry in the badge which controls all decisions, as further described herein below.
Hand Wash Detector
• In a preferred embodiment according to this invention, the handwash detector unit78 utilizes some of the principles of hand wash detection disclosed in U.S. patent application Ser. No. 11/760,100, filed Jun. 8, 2007 and entitled “ Hand washing Compliance Detection System”, published as US2008-0303658, and the related subsequent PCT patent application PCT/US08/066329, published as W02008/154494, published on 18 Dec. 2008. The disclosure of those published patent applications is hereby incorporated herein by reference. It will be appreciated, however, based on the present disclosure, that in alternate embodiments according to this invention, positive confirmation of hand wash compliance may be achieved by other means known in the art. For example, it is known to apply a marker substance to the hands when a person required to comply with hand wash compliance policies washes their hands. Only upon use of appropriate hand wash procedures is the marker substance removed from the hands, and the absence of such a marker (that is, essentially the opposite of the methodology described below), on the hands taken as confirmation of compliance. Such methodology is less preferred than that disclosed below because, in the event that a healthcare worker were, for example, to simply not wash their hands at all, the marker substance would never be applied to their hands and thus, the absence of the marker would not be proof-positive that they had washed their hands. In addition, there may be significant resistance in various professions or locations to having a detectable marker which must be washed off the hands applied to the hands in the first place.
• Thus, in a preferred embodiment according to this invention, theunit78 operates to detect vapors emanating from a person's hands upon application of an appropriate hand wash composition to the hands, or during or immediately after the person has washed his or her hands with a cleaning substance including a “taggant” or “marker” material such as alcohol, (or any other taggant as disclosed in the referenced and incorporated patent publications noted above, including but not limited to, for example, GRAS compounds; volatile, detectable compounds, such as isopropyl alcohol, ethanol, n-propyl alcohol, combinations thereof and the like), some of which are common bactericidal constituents of hand cleaning materials used in hospitals, while others are added for fragrance, or formulation or the like. The cleaning materials include, for example, alcohol-based hand cleaners; antimicrobial soaps; antiseptic hand washes; antiseptic hand rubs; detergents; soaps; waterless antiseptic agents; and surgical hand scrubs. Where alcohol is used as the taggant, it may be preferable for the composition to comprise at least about 5% or 10% or 20% or 30% or 40% or 50% or 60% or 70% or 80% or 90% or even as much as 95% ethanol, isopropanol, n-propanol, or any combination of these compounds, or any intermediate concentration of these compounds.
• During or after the person has washed his or her hands using alcohol- or other taggant-containing soap or other materials, released (either automatically or by mechanical action, which release itself may additionally be monitored and stored according to this invention as evidence or as additional evidence of hand wash compliance) from thedispenser34 or36, the person presents his or her hands close to a sensor, such as aphotosensor110. Ideally, the person does not make physical contact with the apparatus (thus avoiding recontamination of the recently cleaned hands) in order to have the sensor measure the presence of the volatile, detectable compound.
• Thisphotosensor110 receives battery power overline116 and sends a signal over aline112 to thepower management subsystem88 that turns on the other subsystems. Themicrocontroller82 turns on a small fan120 through a signal received over aline118, and energizes avapor sensor111 which is specifically selected to sense a particular volatile, detectable compound, antiseptic agent, or taggant included in the hand wash composition which is then found in the vapor emanating from the hands of the user.
• The activation of the photosensor110 starts the operation of thepersonnel locator76, as it will be described in greater detail below. Alternatively, as also disclosed in detail above, if less precision is required, a motion detector can be used for this purpose, alone or in combination with the operation of thepersonnel locator76.
• Also, in one embodiment according to the invention, an illuminatingLED113 is lit to provide, preferably, white light to illuminate the hands of the person presenting them. In a preferred embodiment according to this invention, the person presenting their hands does not make physical contact with or insert their hands into the detector, but rather, merely holds their hands up to the detector. Air in front of the detector is actively drawn into the detector (as further described below) permitting the sensor included in the detector to measure volatiles emanating from the hands that are presented in proximity to the detector.
• The components shown inFIG. 4 are housed in ahousing126. Thefan122 pulls air out of thehousing126 and ejects it in the direction indicated byarrows122, and draws in room air, including alcohol vapor or other taggant containing vapor from the hands of the user, in the direction indicated byarrows124 to be sensed by thevapour sensor111.
• After a short period of time, preferably on the order of less than a minute, or less than 50 seconds, or 40 seconds, or 30 seconds, or 20 seconds or 10 seconds, or 5 seconds or even, most preferably only a few seconds, or any intermediate time period, when the vapor sensor detects the alcohol or other taggant in the vapor, it sends a signal to themicrocontroller82 through anADC port108. This causes thebadge transceiver90 to send an EM signal, such as an RF or IR signal, to the badge to light the green indicator light56. Also,LED128, visible from outside of theunit78, lights to verify that a proper handwashing operation has been detected.
• Thevapor sensor111 can be any of a wide variety of known chemical detectors, such as those described in the above identified and herein incorporated by reference co-pending U.S. patent application and published PCT application. However, for the purpose of the present invention, it is preferred to use an alcohol detector, which is readily available and relatively inexpensive, such as the Model SB30 MOS Heat-Activated Chemical Resistor made by FIS, Inc. of Markham, Ontario Canada. These detectors are widely used in breathalyzers which are used to detect the concentration of alcohol in a person's breath. Of course, other alcohol detectors can be used instead, as desired.
• In an alternate embodiment according to this invention, the hand wash detector components described above may be miniaturized and housed on the badge or tag provided to each healthcare worker. Alternatively, the hand wash detector may be housed in a separate, but portable, device, issued to each healthcare worker. It will be appreciated, however, that in general, it is preferred for this component of the system to be housed at stationary locations adjacent hand wash stations so that less equipment needs to be carried around by healthcare workers, multiple hand wash adherent workers can confirm their hand wash compliance at only a limited number of strategically placed hand wash detectors, all of which should reduce costs of implementing the system in any particular environment.
Badge Electronics
• FIG. 5 shows theelectronic circuit60 contained in each of the badges or identity tags54 shown inFIG. 2. It will be appreciated by those skilled in the art that other arrangements, layouts, or specifics than the specifics shown in this figure come within the scope of this invention, provided they perform similar functions in similar ways.
• At the heart of thecircuit60 is amicrocontroller132, which can be of the same type or similar to themicrocontroller82 as used in theunit40 shown inFIG. 4.
• Thecircuit60 also includespower management circuitry162 and a, preferably, rechargeablelithium battery pack160. Of course, other types of batteries may be used, such as, for example, non-rechargeable alkaline batteries, or even photovoltaic charging and storage systems known in the art or power storage and provisions systems yet to be developed. Terminals on the badge (not shown) are provided in order to recharge the batteries in the badge, (also referred to herein as tag).
• Also provided is an ultra-low power badge transceiver134, which is an electromagnetic signal transceiver, such as a RF transceiver or IR LED/IR photodiode, that communicates with thelocator unit76 by means of anantenna136 or like means appropriate to the type of EM signal being used to receive RF or other EM ranging signals from theunit76.
• Also provided is an ultrasonic receiving unit ormicrophone138 andsensor circuit140 for receiving ultrasonic ranging signals sent from theunit76. Themicrophone138 is, for example, the Part Number SPMO2OLUDS microphone made by Knowles Electronics, Inc., Itasca, Ill., U.S.A.
• Each of theunits134,140 delivers its output to apulse detection circuit146 or144 which develops a corresponding output pulse. The output pulse of the acoustic circuit is shown at148 and is called a “stop pulse”, and the pulse produced by the EM, (e.g. RF) receiver is indicated at150 and is called a “start pulse”.
• Anoptional vibrator151, of the type used in cellphones or the like, is connected for use, under certain circumstances, in warning the wearer that the handwash status light56 is “off”, (as determined by themicrocontroller132, to which both the handwash status light56 and thevibrator151 are connected), and hand washing is needed. Thiselement151 may, alternatively, be an acoustic signal generator, or light, for example, to provide an audible or visual reminder that hand washing is needed.
Distance Measurement
• Pulses148 and150 are derived from the corresponding ultrasonic and EM (e.g. RF) ranging signals received from thelocator unit76. The two signals have vastly different transmission velocities. The EM (e.g. RF) signals travel at a very high velocity, approaching the speed of light, whereas the ultrasonic signals travel at the speed of sound in air, which is a much, much lower velocity. Thepulses148 and150 are delivered sequentially to a time-of-flight (“TOF”)timing logic circuit152 which delivers an output signal to a 16-bit counter154 formed in themicrocontroller132. A clock signal of 100 KHZ is delivered to the counter by aclock circuit156.
• Thetiming logic circuit152 is set to determine the number of clock pulses between the start pulse150 and thestop pulse148. When that count is less than a predetermined number, which indicates a predetermined distance of the badge from theunit76, an EM (e.g. RF) signal containing the ID of the badge54 is delivered by the transceiver134 through theantenna136 to the unit76 (FIG. 4). Theunit76 then transmits a signal to thebadge circuit60 to light theLED56 to acknowledge that the badge is within range and that a hand wash has been verified uponsensor111.
• This range can be varied as desired, but for the handwash unit locators such as the one shown inunit40, the range can be set at a relatively short distance such as two and a half feet (0.8 meter) so as to prevent the unwanted detection of other badges that might be farther away.
• By locating each of theunits40 and42 near a separate one of two sinks or other hand hygiene stations (which may be waterless stations), and separating the twounits40 and42 relatively far from one another, the proximity discrimination may be set such that no more than one person will come close enough at any one time to thelocator unit76 at a particular station to turn it on. This will largely prevent or eliminate ambiguous simultaneous double-detections.
• If necessary, circuitry can be provided to prevent detection of a second badge before the first one is finished processing. However, it is envisioned that healthcare personnel will quickly learn to avoid this without the need for any special circuitry.
• Of course, it may be possible to use a single unit for two adjacent sinks, since the unit is turned on by a hand presented to thevapor sensor111.
• Referring again toFIG. 5, as well asFIG. 4, when thevapor sensor111 has detected a high enough vapor level on or emanating from the hand(s) of the healthcare worker, the microcontroller causes thebadge transceiver90 to send an EM (e.g. RF) signal through theantenna92 to the transceiver134 of the badge, which then, by way of themicrocontroller132, energizes aLED driver circuit158 which lights thegreen LED56 so that the badge indicates that the wearer has washed his or her hands within the last several minutes.
• Themicrocontroller132 contains a timer, formed by software, which maintains energization to thedriver circuit158 to keep thegreen LED56 “on” for a predetermined time, such as ten minutes, as explained above. After the time has lapsed,microcontroller132 extinguishes thegreen LED56. TheLED56 remains unlit or “off” until relit by another hand washing detection.
• Themicrocontroller132 can be programmed to perform a different timing function, such as turning the light56 out after only a few seconds, rather than 10 minutes, in response to the receipt of different signals, say pulses a few seconds a part, for purposes to be explained below.
• Themicrocontroller132 can also be programmed to measure a different distance, in response to the receipt of different input signals (e.g. pulses of a few seconds apart) for purposes also to be described below.
Data Transfer
• The personnel locator, when it has received the return message from the badge, and when the hand wash detector has finished its work, sends the following data through the ZigBee or equivalent network to the hospital computer storage server or another data storage device:
• • 1. The identity of the locator unit.
  • 2. The badge number that has been read.
  • 3. Whether a hand washing procedure has been performed by the badge wearer.
• The data is sent to the storage location together with a time and date stamp, which is applied automatically by the storage equipment.
• Therefore, there is stored a history of handwashing for each badge wearer at any given date, time and location. This record can be referred to when proving compliance or non-compliance with hand wash regulations, etc.
• In an alternative embodiment, where it is not desired to immediately store the detection data in the main memory of the hospital computer system, time and date data can be added to each information batch stored in a local computer such as thecomputer44 and later down-loaded to the main memory. On-board memory, in the badge or locator circuitry or both may also be provided for temporary, permanent or semi-permanent record keeping or for periodic download to a central database.
• In any event, the time and date of each personnel location event is stored in memory, preferably without having to transmit the time and date information in the wireless network, so as to minimize the data rate required.
• The data stored in the hospital central computer or other data storage device is then available for processing, for report generation, including to hospital administration and, if appropriate, to an external monitoring agency, such as a state or national hand wash compliance registry.
Bed Monitors
• Each of the units of the “bed monitor”50 and “transportation monitor”52 is structurally and functionally similar to or the same as that forming theunits74,76 and, optionally80, shown inFIG. 4, with certain modifications.
• One modification is that, rather than being dormant until the healthcare worker energizes a photosensor by presenting his or her hand, the bed monitor repeatedly, at preset time intervals, sends out ranging signals or “pings” until it detects a badge which is within range.
• The “range” or maximum limit for the distance at which badges are detected usually will be longer than the corresponding distance at hand wash stations, maybe 6 feet to 9 or 10 feet, e.g. (2 to 3 meters).
• In addition, it is preferred that the monitor automatically extinguishes the green LED when the caregiver leaves the patient to go elsewhere, and that the monitor holds the green LED “on” for as long as the caregiver remains near the patient.
• These features will be described in greater detail below.
• When a “ping” is sent out and a badge is detected within range by the monitor, the badge identification number and the condition of the green LED on the badge (“on” or “off”) is transmitted through the ZigBee or equivalent network to the data storage system, where it is time-stamped, dated, and stored.
• This procedure is repeated for each caregiver who approaches the same patient within monitor range. The second or further badges detected with the same “ping” will be ignored and detected by a later “ping”.
• Also, each of the monitors has its own identification number and that information is transmitted and stored in memory as well. Therefore, the storage system now contains the following information:
• • 1. The badge identification;
  • 2. The time and date of entry or approach to a patient in a given location;
  • 3. The identification of the station; and
  • 4. The status of the hand wash LED worn by the caregiver.
• Therefore, as with thedevice40 at the hand wash station, the presence or location of the person at a given time and date is recorded, along with that person's hand wash status when the person arrived at the location.
• Records of the presence of a particular caregiver at the bedside of a particular patient at a given time and date can be of substantial value in corroborating disputed claims of treatment given to the patient. The hand wash status information can corroborate the hygienic standards of the visit, as well as providing data for a compliance profile for the caregiver. From this disclosure, it will be appreciated by the skilled artisan that, in addition to confirming hand wash compliance, the system, device and methods of this invention may be utilized to charge-back to insurance providers and/or to provide record keeping and billing information to confirm actual time spent with particular patients, even in a multi-patient environment by a given health-care provider, including in an environment with many different health-care workers. It would be a simple matter for the skilled artisan to implement appropriate data sorting and selection algorithms for purposes of generating billing records based on the health-care worker location in relation to given patients, independent of the hand wash compliance records which may be separately stored, sorted and analyzed to confirm compliance with relevant hand wash policies or regulations in a given environment.
• In addition, it will be appreciated by the skilled artisan that, in addition to confirming hand wash compliance, the system, device and methods of this invention may be utilized to monitor, evaluate and confirm patient acuity, by determining the number of interactions specific healthcare worker specialists spend with a particular patient. For instance, hospitals frequently use “acuity scores” to determine the nursing ratio for patients as well as assigning the number of other healthcare workers to a particular patient. With the information obtained from the system, device and methods of this invention, hospitals and other healthcare providers (nursing homes, skilled nursing facilities, surgical centers, etc.) will be able to better match the needs of the individual patient with available resources. This should lead to improved patient care, better assignment of healthcare resources, earlier identification of changing patient acuity and ultimately reduction in healthcare costs by better allocation of scare resources.
• The frequency of transmission of the ranging signals, or “pings”, can vary from several per second to only one every 15 seconds or more. It is desirable to make the frequency as high as possible, without creating an excessive power drain on the batteries in the badge. It is believed that a frequency of one pulse every 3 or 4 seconds or less is generally adequate for most installations of the invention, but may be modified at will by, for example, an appropriately appointed system administrator, depending on such criteria as the degree of accuracy required, the level of traffic (personnel coming and going) in a given location, etc.
• In accordance with another feature of the invention, it is preferred to hold a lighted hand wash LED56 “on” while the caregiver wearing the badge is still by a particular patient's bedside, to prevent possible concern by the patient if the LED goes “off” while the caregiver is at the bedside, and also to turn the LED off automatically whenever the caregiver leaves the bedside to go elsewhere, so as to strongly urge the caregiver to wash his or her hands immediately, before approaching another patient.
• These functions can be achieved by proper programming of the microcontroller of the monitor and the badges in a number of ways.
• For example, when a badge is first detected by a bed monitor, the monitor sends an identification signal to the badge and the badge stores it. The repetitive pulses sent by the monitor enable the short timing function rather than the long (e.g. 10 minute) function of the microcontroller. The shorter time is equal, for example, to several “ping” pulses. The new timing cycle is re-started by every successive “ping” received by the badge.
• Thus, the badge LED will stay lit as long as the badge continues to receive one of at least some predetermined number of “pings”, and will be automatically extinguished when the “pings” are no longer received due to the caregiver leaving the bedside.
• As a precaution against prematurely extinguishing a wearer's green light, the automatic turn-off of the light can be conditioned upon the wearer moving out of range of the monitor, as well as the failure to detect “pings” for a time which exceeds a pre-defined length of time. This will reduce the number of incorrect extinguishment occurrences, if there are any.
• When the caregiver proceeds to another patient without first washing their hands, if theindicator light56 has not been turned “off” already, the badge will receive the identification signal of the new bed monitor, compare it with the one stored with the prior patient, and turn the light off when the two identification signals do not match. Also, in this case, the vibrator, audible signal generator orvisual signal151 can be energized to remind the caregiver to wash their hands.
• If the caregiver subsequently washes his or her hands, theLED56 then will turn on again for the full ten minutes, or for as long as that caregiver remains within range of that particular patient's bed or other patient specific monitor, unless another patient is visited sooner.
• The “pings” transmitted from personnel locators at hand wash stations should differ from those sent by bed or transportation monitors, because of the different timing function each would enable. This can be done by varying the pulse rate of the “pings”, or the ultrasonic or EM (e.g. RF) signal frequency, or in other ways know to those of ordinary the skill in the art.
• The correct conditioning of thegreen LED56 on the caregiver's badge can provide a strong inducement towards proper hand washing.
• If the patient can recognize the status, he or she can also remind a caregiver whose LED is “off” and insist that the hands be washed. This will give added incentive to the caregiver to wash without being reminded by the patient.
Transportation Monitor
• If the patient is transferred, for example, from thebed24 to thewheel chair48 shown inFIG. 1, the information identifying the patient can be transferred from the bed monitor50 to thetransportation monitor52 on the wheel chair. This can be done by pressing an exterior button85 (seeFIG. 4) which operates thetransceiver84 so as to transfer the information from theunit50 to theunit52.
• In an alternative implementation of this aspect of the invention, the process of tracking the patient may be made more automatic if each patient in a given health-care facility is provided with a patient locator. Every patient in such facilities typically is provided with an identification tag of some sort, frequently in the form of non-detachable (without destruction thereof) wrist tag. Such patient-specific wrist tag, or other patient associated locator device may be implemented, such that at any given time at any given location in the health-care facility, the patient's location is easily defined and recorded via communication with such patient-specific locators and the other elements of this invention. In this fashion, it would not even be necessary for a health-care provided to remember to press the exterior button,85, in order for the information relating to the particular patient to be transferred from theunit50, for example, to theunit52. This would occur seamlessly, by virtue of appropriate hand-shake sub-routines built into the communication software. The patient-specific monitor may then operate in a fashion equivalent to that described above for the bed monitors with respect to detecting, logging and transmitting information about healthcare providers who come into sufficient proximity of the patient to require them to have complied with established hand wash requirements for patient contact. In this embodiment, the monitoring is conducted by a monitor physically associated with the patient such that the monitor moves with the patient when the patient moves
• Subsequently, theunit52 works in the same way asunit50 to indicate patient contact by healthcare workers and cause storage of the badge identities and times. Storage of the monitor number does not, in this case, give location.
• When the patient is returned to his or her bed, the information can be transferred from theunit52 to theunit50 again, as described above. The contact of the patient with specific healthcare workers at specific times, again is transmitted through the network and stored in computer memory to provide records for the future.
Computer Network
• The ZigBee computer network used in the invention is shown schematically inFIG. 6 of the drawings. Because a wireless local area network can be extremely variable in configuration,FIG. 6 is only representative of the many different configurations which can exist. It will further be appreciated that an implementation of the present invention which includes wired communication between various elements of the system represented inFIG. 6 would not, thereby, be outside the scope of the embodiments contemplated for implementation of this invention.
• ZigBee network technology is well known and components of the system are standardized. Nonetheless, each separate facility and each separate local area of a large facility may have a different network configuration, depending upon such things as wall locations, equipment locations, etc.
• Each network should have a coordinator, one or more routers, and one or more end devices.
• In theFIG. 6 network, the network coordinator is indicated at164. It serves as one “node” of the network. The dashed line between various nodes of the network indicate possible paths of travel of wireless signals.
• Routers172,174 and176 are positioned as needed. Thecoordinator164 is also a router and the coordinator, together with theunits172,174 and176, determine the routing of wireless signals in the network. The end devices inFIG. 6 include theunits40,42,50,52 and72, all of which have been described above.
• In the network shown inFIG. 6, wireless signals from the end devices are routed along the best route available, which is determined by software used in the system, and delivered to a gateway device which is, in this case, thePC44, which also is shown inFIG. 1.
• The data is delivered from thePC gateway44 through thelarger network166 of the hospital or other facility to a bank ofservers170 where the data is stored and from which it can be retrieved to prepare various records or reports for patients, personnel and, if appropriate, external regulatory authorities.
• As noted above, alternatively, the data can be temporarily stored in the memory ofbadge60, thelocator40, thecomputer44 or a connected disk file, and then later downloaded to theserver170. If this is done, the data is automatically timed and date stamped as it is stored in the memory of thecomputer44 or other intermediate data storage.
• Therouters172,174, and176 and thecoordinator164 are powered on all the time so they can “listen” for communications from the end devices and deliver stored messages, etc. Therefore, these devices should use house current through regular outlets, rather than batteries with appropriate power and data backup systems known in the art.
• Advantageously, the end devices can be stand-alone battery-operated devices which “sleep” most of the time. This is true for the hand wash detectors and the personnel locators adjacent the hand wash location.
EXAMPLES
• Having generally described this invention, including the best mode for making and using the invention, the following specific examples are provided to further expand the written description of the invention, and to ensure that those skilled in the art are enabled to practice the invention without undue experimentation. The specifics of the examples provided below are not intended to be limiting, and variations, equivalents and non-critical modifications of the specifics included in these examples should be considered as coming within the scope of the general disclosure provided herein and the appended claims.
Example 1A Given Healthcare Worker Visits Two Different Patients in an Establishment in Which the Invention is Implemented
• Following is an example of a sequence of events which might occur for a given health worker.
• First, the worker applies an appropriate amount of an appropriate hand wash composition to his or her hands. This may be achieved by actuating a dispenser of a composition which has been tested with the remaining components of this invention to include a taggant detectable by the sensor used in the implementation. The taggant may be alcohol included in a soap composition, or in a waterless hand hygiene composition or it may be any appropriate, non-toxic detectable volatile compound. Preferred taggants according to this invention include, but are not limited to, GRAS compounds, and compounds discussed and disclosed in, for example, US2008-0303658 and WO2008/154494. Alternatively, the dispenser may automatically activate upon detecting sufficiently proximate motion at a motion sensor included in the dispenser, or upon establishment of communication between a given dispenser and the identity tag of a given healthcare worker that has approached the dispenser sufficiently closely to permit such communication to be established. In yet a further alternative, the dispenser may dispense an appropriate quantity of a hand wash agent upon reading an appropriate biometric, such as a retinal scan, facial recognition software, or fingerprint of the person demanding, by their presence at the hand wash station, dispensing of hand wash agent. The dispenser ideally dispenses a pre-determined quantity of hand wash composition, and therefore taggant, onto the hands of the worker. The healthcare worker, on application of the hand wash composition, either immediately presents their hands to the detector, or washes his or her hands and, in the process or shortly after completion of the hand washing, presents them to the hand wash detector which lights the green LED on his or her badge. The LED is set to automatically turn off after a system administrator defined pre-determined period of time (e.g. a ten minute time delay).
• The worker promptly goes to visit a first patient in a bed. When he/she enters the range of the bed monitor for that bed, the bed monitor detects his/her badge number and LED condition, and sends that data, together with the bed identification number through the network to the central computer system for storage. The information is time and date-stamped as it passes into the central computer storage system.
• The healthcare worker either examines the patient, thereby making physical contact with the patient, or sits by the bedside of the patient for, say, five minutes, and then gets up to leave to visit another patient. After the healthcare worker's badge has not sensed a “ping” from the bed monitor associated with the first patient for a predetermined length of time, the green LED is automatically extinguished even though the ten minute (or any other pre-determined) time period originally set for the badge has not yet expired.
• Before going to visit the next patient, the healthcare worker has to again wash his/her hands and submit them to a hand wash detector which then relights the green LED, and the healthcare worker can proceed to visit the next patient.
Example 2A Healthcare Worker That Takes a Break
• As another example, assume that the healthcare worker described in EXAMPLE 1 is finished seeing patients for the time being and takes a lunch break of one half hour. If the green light on the worker's badge was on at the start of the lunch break, it automatically turns off when the pre-set time, e.g. ten minute time limit, has been exceeded.
• Before the worker can resume seeing patients, he/she must again wash his/her hands in order to re-light the green LED. This is beneficial because, even though the healthcare worker has not been visiting other patients, his/her hands have been exposed to areas and surfaces in the hospital or the outside environment which might bear pathogens, and washing is, therefore, beneficial.
• The record that is stored and prepared in the central computer system of the hospital will indicate when the last hand washing occurred before the worker started his/her lunch break, and will show no patient contact for one half hour while the worker was on lunch break, and then will show the subsequent hand washing at the end of the lunch break, before the visit to the next patient.
• If desired, a bed or transportation monitor can be located in a contaminated area or area in which there is extra danger of a caregiver picking up pathogens. The caregiver would be required to wash hands on leaving.
Example 3Process Flow for Entire Operaitonal Embodiment of The Invention
• To further describe the invention and enable those skilled in the art to make and use the system, the following example, with reference toFIGS. 11-15, provides a detailed process flow description of one preferred embodiment of the invention. Those skilled in the art, based on this disclosure, would be easily enabled without undue experimentation, to implement appropriate software and hardware configurations and programming, consistent with the purposes of this invention, to implement the logic flows described below.
• With reference toFIG. 11,FIG. 11A provides a logic diagram showing the Hand WashStation Process Flow300. Starting at301, the system performs an initialization routine on power-up. If, in the course of the initialization routine, in which a routine battery check is performed, if the battery level is low, a yellow LED is illuminated to show this condition, and the process is put intosleep mode300A, rather than continuing with the remaining steps of the process flow shown inFIG. 11. On the other hand, if there is no low battery condition, then the system proceeds on to a wake-up routine301 from the processor sleep mode, which is activated by thephotosensor110 shown inFIG. 4 sensing the presence of a user's hand's in sufficient proximity to the detector to demand initiation of a hand wash compliance detection cycle.
• Once wake-up has occurred,subroutine303 is initiated, in which thefan122 is turned on and, if included,white LED102 is illuminated. If a low battery level is detected, theLED102 is changed to a yellow color and an indication of low battery level is sent toLCD104.
• Once the fan has been activated,sensor subroutine304 is initiated, such that A/D signals are compared305 between the sensor signal and a reference signal for a set period of time, say four seconds, to determine if the sensor signal is less than, the same as, or greater than the reference signal. If less than, then the logic continues to308. However, if the sensor signal is greater than the reference signal,subroutine306 is entered, followed by setting the badge indicator LED56 to a not lit or not green state, and from there to309, see below. If the sensor signal is less than the reference signal at305, then at308 the LED is turned on to indicate that hand washing has been detected. The infra-red, IR, (or other electromagnetic, such as radiofrequency, RF) signal is monitored at309 for a set period of time, say 4 seconds, to detect whether a badge ID in range can be detected,310, and if no signal is detected,subroutine311 is entered, following which the hand wash station is placed into a sleep mode until a new wake upsignal302 is detected. However, if a badge is detected in range and successful handshake protocols to establish communication occur313, then the station sends an infrared (or other EM) signal314, including the handwash station identity, a cyclic redundancy check value (CRC, a standard computer algorithm for error correction) along with a command to set the badge LED to green to show a recent hand wash event or not green, indicating no recent hand wash event. An infrared or RF pulse initiates an acoustic pulse, after some delay315, and this is checked,316, for receipt, for example, of a five hexadecimal character information string including the badge identification information, the hand wash compliance status of the badge at the time of data transmission and the in-range status of the badge. If the badge is not in range or any of the required data is not received, the system resets to step309 demanding a further hand wash procedure. If, however, all of the required information is properly received, then317 the green LED on the hand wash station is lit to confirm that an acceptable hand wash procedure has been achieved, the information is logged and saved318 to confirm communication with the particular badge and worker and the status of the hand wash on the badge. The data is transmitted, via a Zigbee or like network, to store the data in a central database,320, and the system then resets321 to initial status to await a new wake-up event.
• Referring now toFIG. 12, which provides a process flow diagram400 for the badge implemented according to the invention. At401, the badge is switched on, thereby initiating a badge initialization routine in which the battery voltage A/D is checked and flagged by illumination of a yellow LED if the battery is low. If the badge initialization passes,402, then if the badge detects an infrared or equivalent, e.g. RF, EM pulse, the badge processor is woken to check battery voltage, with a yellow LED being enabled if a low voltage condition is detected. If this check passes, then403, if an IR, RF or equivalent EM signal is received from the locator station, the badge determines if the responding station is a hand wash station or a patient bed monitor, based on the received station identification code. The badge responds appropriately404 depending on the type of station detected, such that, if the wake up station is ahand wash station405, the logic described forFIG. 13 applies, and if the wake up station is a patient bed monitor,406, the logic described forFIG. 14 applies. In this fashion, the badge substantially determines the subsequent system logic. The initial EM pulse synchronizes all communication in the system, which is advantageous because if all communications are synchronized, then the receiver or other elements not needed in intermediate times may be turned off or placed in sleep modes, thereby gaining power savings.
• Assuming that the badge at404 determines that the wake up station is a hand wash station, then, reference is now made toFIG. 13, which provides a diagram of logic flow for communication between the badge and ahand wash station500. The badge turns on501 the time of flight (TOF) ultrasonic pulse detector. The badge, on receiving an infrared pulse on the IR receive line, or, equivalently, an RF or other EM pulses, sets the time at zero; the time counter is then active until a later arriving ultrasonic signal is received. The badge then determines,502, based on the difference in receipt times for the ultrasonic and EM signals, the distance of the badge (and thus the personnel carrying the badge) from the transmittingstation503. In the event that the distance is greater than a pre-set distance, say two feet, then subroutine504 initiates to indicate that the badge is not in range and the processor is placed into sleep mode. On the other hand, if the distance is less than the pre-set distance, say two feet, then thesubroutine505 initiates, first confirming that the battery status is adequate (if not a low battery indicator is illuminated, as described above), and then506, the badge transmits badge identification information, status and a CRC (cyclic redundancy check, to confirm data and communication integrity), along with the status of the badge indicator as green or not green. In response, a command is received from thebase station507 to turn on the green LED when the handwash procedure has been confirmed, following which,508, either a timer clock is initiated for a set period of time, say ninety seconds, for the green LED to remain illuminated. Then,509, the badge remains in a query state until either EM (such as IR or RF) communication from a bed station (bed monitor) is initiated511, in which case the badge-bed station communication process flow described below in reference toFIG. 14 is initiated, and if not, the green LED times out510, which would require the healthcare worker to re-initiate a hand wash procedure in order to once again illuminate the green LED to indicate hand wash compliance.
• Referring now toFIG. 14, which pre-supposes that the badge has received an IR or other EM communication from a patient bed station or other patient-specific communicator, there is provided a process flow diagram600 showing the communication between the badge and the patient location communicator. Thus, at601, the badge energizes the TOF ultrasonic pulse detector, and awaits an acoustic pulse, from which, bydifference602, the distance from the patient station is calculated. The EM pulse detected by the badge queues the badge to receive acoustic pulses which, when received, initiates a stop signal, allowing synchronization as discussed above. A rule of thumb is, for acoustic transmission times, 1 foot is travelled per millisecond. Thus, if there is a time delay of 6 milliseconds or less, for example, from the time of receipt of the EM pulse until the time of receipt of the acoustic pulse, then the particular badge in question is within the six foot proximity set for this particular example. Of course, the discrimination may be modified as needed for a given location or in a given application of this system. If the calculated distance is greater than a pre-set distance, say six feet, then the green LED on the badge times out604. However, if the distance is less than the pre-set distance, say six feet, then the battery status is again checked605 to ensure proper operation of the badge, and the status of the LED is queried. If the LED is not illuminated and showing a green hand wash compliance status,607, a cross-check is initiated such that if the bed station has logged a green LED approach for this worker already within a pre-set time, then the badge LED blinks green twice608 to confirm that, in fact, the worker's hand wash compliance status is verified. If, however, the bed station has not already logged a green LED compliant status, then611, a vibration or equivalent alternate alert is initiated to alert the worker that they need to wash their hands before proceeding any closer to or making any contact with the patient to which they have been detected to be approaching. Any number of alert signals may be used, including, for example, a visual, an auditory, or a vibrate signal, to remind the worker to wash their hands. Preferably, a vibrate signal is used as this is non-intrusive and provides a discrete reminder to the worker. In one preferred embodiment, the vibrate reminder cycle is as shown in the figure,611, wherein a first short, single vibration is sent, then, after a short delay, say two seconds, two vibrations are sent and then after a further delay, if no hand wash event is detected, three vibrations are sent. At this point, if no hand wash event is logged, an auditory signal may be initiated and/or a non-compliant event may be reported to the hand wash compliance system (referred to as the HyMarks™ software), following which the badge is placed in asleep mode614. If, on the other hand, at606 the green LED was on, the badge LED is turned off609 once contact with the bed station has been established. After a pre-set amount of time, say six seconds, the badge LED flashes briefly if the badge is still in range of the bed station. This process continues until a new hand wash station or patient location is detected. Alternatively, at608, if the bed monitor logged a green LED, then either way, from608 and609 the process flows to610 the badge completes its handshake with the bed monitor, transmitting an EM (e.g. an IR or RF) signal including the badge number and the green LED hand wash compliance status. At612 the badge will pulse inhibit for a pre-set period of time, say five seconds, and then go back tosleep mode613 pulsing every 1 second. This permits control of a situation where, for example, a crisis occurs at a particular patient location, and a large number of HCWs rush to attend to the patient. A subsequent cacophony of EM pulses might ensue. Thus, per this aspect of this embodiment of the invention, the one particular HCW badge identity information is picked up, logged, their hand wash status is checked, and then the next badge identification is sequentially recognized. The badge power on and off sequence involves, in a preferred embodiment, the following steps and elements: Badge power ON: If the badge power is off and the power switch is held down for several seconds, the badge will vibrate three times and the Green LED and Yellow LED will blink simultaneously. Releasing the power button when vibration sequence starts and the badge is powered ON.
• Badge power Off: If the badge power is on and the power switch is held down for several seconds, the badge will vibrate once and no LEDs will blink. Releasing the power button when the vibration occurs and the badge is powered off. The badge will not respond to bed or hand wash stations when in the power off mode.
• Referring now toFIG. 15, there is provided a process flow diagram700 in which the bed station logic and wake-up procedure is described in detail. Thus, on power-up, the bed monitor or other patient associated monitoring device initiates aninitialization routine701, starting from a sleep mode, upon receiving a wake up signal from the badge sending an EM (e.g. infrared or radiofrequency or other appropriate EM) pulse which is received by the bed EM (infrared, RF or other appropriate)receiver702. The bed station then transmits its identifying data via its EM (e.g. infrared)transmitter703. The bed station further sends an infrared (acoustic start pulse) after somedelay704, along with an acoustic pulse. If the badge determines from the acoustic TOF that it is in range of the bed station then it sends its identifying data to the bed monitor for subsequent logging and reporting.
• Once the bed station logs an EM (e.g. infrared) receive signal from thebadge705, the process flow continues to706. However, if no such confirmation is logged, then the bed station resets to asleep mode702, to await an appropriate badge transmitted wake-up signal.
• Once the bed station has been properly woken705, the bed station then logs the identification information of any and all respondingbadges706. The bed station logs all such badges in range for a pre-set amount of time, say oneminute707, and constructs and transmits a report via the Zigbee or like network when any new badge enters or leaves the log. To avoid errors, in a preferred embodiment, the bed station may be programmed to require two exact duplicate entries before sending such a report via the network.
• To confirm proper operation, the bed station performs a battery level check, and if any low battery condition is detected, the monitor sets a yellow LED signal to illuminate708. All of these steps having been completed, the Zigbee report is assembled709 and the report is transmitted to the central report database over appropriate communication lines andprotocols710 such as, for example, a UART buss known in the art. Once completed, the bed monitor resets all enabled lines back to its initial state, placing the processor back into asleep mode711, thereby readying the bed processor for a new wake up signal as at702.
• The above description of the invention is intended to be illustrative and not limiting. Various changes or modifications in the embodiments described may occur to those skilled in the art. These can be made without departing from the spirit or scope of the invention.

Claims (16)

1-36. (canceled)

37. A system for locating personnel in an enclosed facility having a plurality of spaced-apart stations, said system comprising:

(a) a separate indicator badge or tag for each of said personnel;

(b) at least one detector or monitor for detecting when one of said badges is located within a predetermined distance from one of said stations, and for reading information from the detected badge or tag at said station;

(c) each of said detectors or monitors including first and second wireless transmitters for transmitting first and second wireless signals, the signals having transmission velocities different from one another; and

(d) a device for detecting the difference in transmission times between said first and second signals and indicating when said difference is below a predetermined value.

38. A system as inclaim 37 in which at least one or a combination of the following features is included:

(A) said information includes the identity of said badge, said system further comprising equipment for transmitting and storing the identity of said badge, the identity of the station from which said information is transmitted, and the time of such transmission;

(B) said enclosed facility comprises either or both of the following features:

(i) has walls and at least some of said stations are separated from one another by one or more of said walls, said stations being arranged in a wireless network with transceivers for transmitting signals to and receiving signals from one another, and to a storage device;

(ii) is selected from the group consisting of a patient care facility having multiple patient care locations and hand washing locations, said stations being located in at least some of said hand wash locations and at least some of said patient care locations, a medical laboratory, a clean-room manufactory, a food processing facility, and a facility otherwise requiring frequent hand washing to retard the distribution of pathogens;

(C) wherein said system includes a hand cleanliness detector at each of a plurality of said stations for detecting and developing a signal indicating the hand cleanliness of the person wearing said badge when it is detected, in which each of said badges has an indicating device for indicating said hand cleanliness, and a wireless signal receiver for receiving said signal from said hand cleanliness detector and enabling said indicating device.

39. A system as inclaim 38 in which at least one or a combination of the following features is included:

(A) said indicating device is selected from the group consisting of a visual indicator; a vibrator; and a combination of a vibrator and a visual indicator;

(B) each of said badges has a timing device for holding said indicating device in a selected condition for a pre-determined length of time;

(C) each of said hand cleaning detectors comprises a device for detecting a hand cleaning material on at least one hand of the person wearing said badge and in which said material contains a taggant and each of said cleaning detectors is adapted to detect airborne samples of said taggant; and

(D) said material is selected from the group consisting of alcohol-based hand cleaners; antimicrobial soaps; antiseptic hand washes; antiseptic hand rubs; detergents; soaps; waterless antiseptic agents; and surgical hand scrubs.

40. A system according toclaim 37 for monitoring hand cleanliness in an enclosed patient care facility having a plurality of spaced apart stations, said system comprising:

(a) an indicator tag worn by each of said personnel;

(b) a detector at each of said stations for detecting each of said tags when it is located within a predetermined distance from said detector, and for reading information from said tag;

(c) each of said detectors including first and second wireless transmitters for transmitting first and second wireless signals having different transmission velocities;

(d) a device for detecting the difference in transmission times between said first and second signals and indicating when said difference is within a predetermined range;

(e) a hand cleanliness detector at each of said stations for detecting airborne taggant material in hand cleaning material at said station and sending wireless signals responsive to said taggant detection; and

(f) each of said tags having indicator means for indicating the hand cleanliness of the wearer of said tag, and including a wireless receiver for receiving said wireless signals from said hand cleanliness detector to enable said indicator means.

41. A system as inclaim 40 in which one of said transmitters transmits acoustic signals and the other of said transmitters transmits electromagnetic signals.

42. A method of locating personnel in an enclosed facility having a plurality of stations therein, the steps of:

(a) locating a detector at each of said stations for detecting the presence of a person when said person is within a predetermined distance from said detector by directing two signals of different velocities towards said person and measuring the time difference between the receipts of said signals by said person and comparing said difference with a predetermined value; and

(b) developing and transmitting to said detector information identifying said person.

43. A method as inclaim 42 including at least one or a combination of the following features:

(A) storing for each person detected the information received and the time when it is received; and

(B) locating a hand wash detector in at least some of said stations, said enclosed facility being one requiring frequent hand washing by personnel to retard the distribution of pathogens.

44. The system according toclaim 37 comprising an identity and hand wash status badge to be displayed on healthcare personnel, said badge comprising:

(a) a display member;

(b) a remotely actuatable visual hand wash status indicator on said display member;

(c) a timing device for holding said indicator “on” for a first predetermined time period after being turned “on” and then turning said indicator “off” when said time period expires; and

(d) said timing device being remotely actuatable to enable it to selectively hold said indicator “on” for a shorter length of time than said first time period.

45. The system according toclaim 44 wherein said badge comprises at least one or a combination of the following features:

(A) a time-of-flight detector for detecting the difference in arrival times of two signals of different velocities sent from a measurement station and sending an identification signal when said difference is below a predetermined level;

(B) a vibrator for vibrating selectively when said indicator is “off”; and

(C) a wireless transceiver for transmitting badge identification and status indicator information in response to the receipt of signals from which the location of said badge within a predetermined distance from a monitor station can be determined in which said transceiver is adapted to transmit said information at different predetermined distances from said monitor station in response to the receipt of different wireless signals received from said monitor station.

46. The system according toclaim 37 which is a healthcare facility personnel locator and monitor system comprising:

(a) a plurality of tags or indicator badges for carrying by personnel present in said facility, each of said tags or indicator badges being responsive to wireless signals from one of said monitor or detector units to transmit identification signals identifying one of said personnel associated with said tag or indicator badge;

(b) a plurality of monitor or detector units, each mounted on or near one of a plurality of patient support structures in said facility;

(c) each of said monitor or detector units having equipment for sending ranging signals to said tags or indicator badges;

(d) a further device responsive to said ranging signals for determining whether the distance of each tag or indicator badge from said monitor or detector unit is within a predetermined distance; and

(e) said monitor or detector equipment being adapted to receive said identification signals from one of said tags or indicator badges which is determined to be within said predetermined distance from said monitor or detector unit, and for transmitting a corresponding identification signal to another device for storage together with the time of detection.

47. The system as inclaim 46 in which said tag or indicator badge includes an indicator for indicating the hand wash status of the carrier of said tag or indicator badge, and said tag or indicator badge includes a transmitter for transmitting to said monitor or detector a signal indicating said hand wash status, and in which said equipment in said monitor or detector is adapted to transmit a signal corresponding to said hand wash status signal to said other device for storage.

48. A system as inclaim 46 in which at least one or a combination of the following features is included:

(A) the indicator included in said tag or indicator badge has an “on” condition to indicate “hands washed” status, includes a holding device for holding said indicator in the “on” condition for a predetermined time after the carrier of said tag has washed his or her hands, and further includes a second holding device responsive to signals from said monitor for holding said indicator in the “on” condition for as long as said tag remains within said predetermined distance from said monitor;

(B) said system includes at least one or a combination of the following features: (a) a device for turning said indicator off when the indicator is in a condition indicating “hands washed” status and when said tag has been moved beyond said predetermined distance from said monitor: (b) in which said second holding device is responsive to turn off said indicator, to the simultaneous cessation of receipt of pulsed signals for said pre-determined length of time and the movement of said tag to a distance greater than said predetermined distance from said monitor;

(C) said ranging signals comprise first and second wireless signals of different transmission velocities, said system including a device for measuring the difference between the time of flight of said wireless signals and determining when said difference falls below a predetermined minimum in which said monitor is set to repetitively send pulsed signals at regular time intervals, and said second holding device is adapted to start a timing function upon the receipt of each of said pulsed signals and turn said indicator off when said pulsed signals have ceased to be received for a predetermined length of time;

(D) said equipment in said monitor is adapted to transmit to said other device for storage information indicating that said indicator has been turned off, and the time of that occurrence;

(E) said system includes one or more of said monitor units at a hand washing station, and a hand washing detector for detecting a hand washing procedure by the carrier of said tag, and for energizing said indicator on said tag, said monitor units being associated with one another in a wireless network through which information is transmitted to said device for storage;

(F) each of said monitor broadcasts its unique identification signal, and each of said tags stores that signal, compares it with a prior signal received from another monitor, and turns off the indicator on said tag if the compared signals do not match; and

(G) said system includes a motion detector located adjacent each of said patient support structures for enabling said equipment for sending said ranging signals only when said motion detector detects motion by a person within an area adjacent said patient support structure, including the step of holding said indicator in an activated condition while said wearer is in said near vicinity of said patient.

49. A system as inclaim 48 in which said monitor unit includes a transfer device for selectively transferring information regarding the support structure from whose monitor unit information is to be transferred to a different one of said support structures to facilitate maintenance of monitoring when a patient is transferred from one to another of said support structures, or where said monitoring is conducted by a monitor physically associated with the patient such that said monitor moves with said patient when said patient moves.

50. A method according toclaim 42 which comprises controlling an indicator on a tag or indicator badge worn by a healthcare worker in a healthcare facility, activating said indicator for a given time period after the completing of a hand washing procedure by the wearer of said tag, and de-activating said indicator whenever said wearer of said tag leaves the near vicinity of a patient in said facility.

51. A system according toclaim 37 which is a healthcare facility personnel locator and monitor system comprising;

(a) a plurality of monitor units, each mounted on or near one of a plurality of stations in said facility;

(b) a plurality of tags each carried by one of the personnel present in said facility, each of said tags being responsive to wireless signals from one of said monitor units to transmit identification signals identifying one of said personnel associated with said tag;

(c) each of said monitor units having equipment for sending interrogation signals to said tags;

(d) a motion detector responsive to the detection of the motion of a person adjacent said station; and

(e) said monitor equipment being adapted to receive said identification signals from one of said tags which is determined to be within the range of said motion detector, and for transmitting a corresponding identification signal to another device for storage together with the time of detection in which at least one or a combination of the following features is included:

(A) said tag includes an indicator for indicating the hand wash status of the carrier of said tag, and said tag includes a transmitter for transmitting to said monitor a signal indicating said hand wash status, and in which said equipment in said monitor is adapted to transmit a signal corresponding to said hand wash status signal to said other device for storage; and

(B) in which said equipment sends said interrogation signals repeatedly at timed intervals after being started by said motion detector and until no motion has been detected for a pre-determined length of time.

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