HK1088202A - Device and method for passive patient monitoring - Google Patents

Description

Apparatus and method for passive patient monitoring

Background

The present invention relates generally to medical devices, systems and methods. More particularly, the present invention relates to devices, systems, and methods for passive patient monitoring.

Monitoring patients is an important aspect of patient care in a number of different specific contexts. For example, in a general care floor (general care floor) or ward of a hospital, monitoring key physiological signs such as respiratory rate, heart rate, and blood pressure is an essential component of patient care. It is also beneficial in a general care ward or other area of a hospital to monitor a patient on a bed or chair that is or is not in the patient's hospital room, and to monitor the patient's movements on that bed or chair. Some patients are at risk of falling and/or injuring themselves if they leave their bed. If a patient stops moving in bed, this may mean that the patient is dying, in a coma, or is experiencing some medical complication, which makes the patient difficult or impossible to move and needs attention. Excessive motion may indicate a seizure or other condition.

Due to practical difficulties, such as lack of manpower and resources, patients in general care areas of hospitals are often monitored only intermittently. For example, key symptoms of a patient on a general care floor are typically recorded every 3-4 hours of testing by a nurse or medical technician. Meanwhile, since health care organizations (HMOs) and other managed care providers (managed care providers) have introduced the age of people and the time allowed for admission (hospital accommodations), the severity of health problems among hospital patients is increased, and the number of patients is increased as a whole. Consequently, hospital population continues to increase and hospital patients generally require closer monitoring than in the past. However, significant and increasing short of care (nursing shortage) situations make it impractical, if not impossible, to increase direct patient monitoring by adding healthcare personnel.

Physiological monitoring is also important in other specific environments. For example, when a patient is undergoing a surgical procedure under conscious sedation (conscious diagnosis) such as in an outpatient operating room in a hospital or operating center, or in the treatment room of a physician's private clinic, the patient's respiratory rate and heart rate should be continuously monitored. The standards set by the Joint Committee for authorization of health authorities, JCAHO, require such continuous monitoring of respiratory and heart rates in order to detect and prevent adverse effects of sedating drugs or patients undergoing operation under conscious sedation. Other situations where physiological monitoring may be important include: infant monitoring to detect early signs of Sudden Infant Death Syndrome (SIDS); patient monitoring in an operating room; patient monitoring during emergency delivery; patient monitoring in nursing homes (nursing home) and special care homes (skilfurring facility); home monitoring and the like.

Failure to adequately monitor a patient in any one of a number of specific settings may have serious consequences. In hospitals elderly patients who should be in bed often become disoriented and leave their bed and experience injuries such as hip, arm or wrist fractures. Statistics show that over 25% of elderly hip fracture patients may never leave the hospital after receiving treatment for such fractures. Other patients may die silently during the 4 hour period between nurse care examinations. The patient's family members may be very angry when they know that death may have been avoided, or at least may have been delayed long enough to allow them to arrive at the scene. In other instances, critical physiological functions, such as lung or heart function, may deteriorate significantly without detection due to inadequate monitoring. Thus, the possibility of adverse Medical accidents and Medical impairment (Medical Malpractice) liability is prevalent in the general care units of hospitals and in other settings where continuous and proper monitoring using currently available systems is impractical or impossible.

Current systems for patient monitoring generally do not provide convenient, continuous, day-to-night monitoring. For example, in a general care unit of a hospital, monitoring typically involves a group of nurses patrolling patients one by one at 3 or 4 hour intervals to obtain key signs such as respiratory rate and heart rate. In some hospitals, this monitoring may be enhanced by one or more devices, such as a bedside pulse-oximeter, which monitors pulse and oxygen saturation via a small clip-like device attached to the patient's finger. The pulse oximeter can be designed to reach a certain pulseAnd a threshold level of oxygen. An example of such a system is available from Nellcor: (R)www.nellcor.com) OXIDET  IICentral Station Network available from Inc. Pulse oximeters do not measure respiratory rate, which is often one of the earliest signs of patient distress. In the specific context of a general care hospital, the most commonly used method of measuring respiratory rate is direct observation by a nurse, a certified care assistant or the like, which is highly inaccurate because it is difficult to calculate the number of breaths based only on observing the chest movements of the patient. Other currently available methods for measuring respiratory rate include: impedance pneumography (impredance pneumography), which is complex and rarely used in specific environments outside the neonatal intensive care room; and capnography, which is also difficult and requires at least the patient to be secured to a nasal cannula (nasal canula). Other currently available monitoring systems attempt to measure other patient parameters. This includes an Electrocardiogram (ECG) transmitter that is used in a telemetry unit to monitor the physiology of the patient's heart. The ECG electrodes are attached directly to the patient's skin and a transmitter connected to the electrodes is carried by the patient so that physiological data relating to the patient's cardiac function can be transmitted to a central monitoring station. Blood pressure cuffs (blood pressure bags) may be secured to the patient and programmed to intermittently, automatically read the blood pressure.

These currently available systems and methods for monitoring patients have several common features. Essentially, they all require connecting the patient's body to the monitoring device. Many devices, such as automatic blood pressure cuffs, provide only intermittent monitoring. Connecting the body to the monitoring device can be cumbersome and inconvenient for the patient, sometimes resulting in patient noncompliance, for example, when the patient removes the device due to discomfort. Fixed devices may also become loose, change position, become partially dislodged, etc., which results in inaccurate monitoring data. Intermittent monitoring can lead to missed or delayed diagnosis and adverse patient outcomes, particularly in very debilitating patients whose pathology can change rapidly.

Nor do current systems monitor patient movement or positioning, such as on a bed or chair. As mentioned above, patient movement may be a necessary means of supervision. For example, a complete lack of movement of the patient on the bed may indicate that the patient has left the bed. While a relatively slight movement, a significant reduction in movement, or the like can indicate that the patient is still until some medical problem may have occurred. A significant increase in patient motion may indicate a seizure or significant patient discomfort.

Accordingly, it would be beneficial to have an apparatus, system, and method for passively monitoring one or more patients. Ideally, such passive monitoring would be continuous, without requiring an inconvenient or annoying direct connection of the device to the patient. It would be advantageous if such passive monitoring could detect movement and/or position of a patient on a surface, such as a bed or chair, and if respiratory rate, heart rate and/or other physiological parameters could also be monitored. Desirably, monitoring may include activating an alarm when one or more thresholds are reached, or some predetermined negative trend occurs, and monitoring may also include providing data to the user in other forms, such as on a monitor. It would also be desirable to provide an apparatus and method for monitoring multiple patients simultaneously. At least some of these objectives will be met by the present invention.

Disclosure of Invention

The devices, systems and methods of the present invention are used to passively monitor one or more patients, infants, nursing home patients, home healthcare patients, or any other individual or person for whom monitoring can be beneficial. "Passive monitoring" generally means that monitoring according to the present invention does not require direct attachment of the device to the patient. In general, a patient is coupled to the device of the present invention by simply having the patient lie, sit, lean, stand or the like on the surface on which the device is mounted, or in some embodiments, having the patient wear the device against the skin or through one or more layers of clothing. Thus, the term "passive monitoring" as used herein generally refers to the case: the device of the present invention generally does not need to be secured directly to a patient to monitor the patient.

In some embodiments, the sensor device of the present invention comprises at least two piezoelectric sensors in combination with a planar or flat pad, which may be placed on a bed, chair seat, chair back, wheelchair, operating room table, dental chair, or the like. The sensor device may be placed under one or more layers of bedding and may monitor the patient through one or more layers of patient clothing, patient gowns, or the like. The sensor device will typically be coupled to the processor by wired or wireless communication. The processor receives the data detected by the piezoelectric sensor and processes the detected data into a form that can be utilized by a physician, nurse or other user. Any suitable patient parameter may be monitored, such as, but not limited to: patient motion, patient position, respiratory rate, heart rate, blood pressure and/or the like. Such devices may be used for a single patient, such as a patient undergoing a procedure under conscious sedation, or may be used to monitor multiple patients simultaneously, such as multiple patients on a general care floor or ward of a hospital.

In another aspect of the invention, a method of passively monitoring at least one patient includes: providing a sensor device on a surface, the sensor device having at least two piezoelectric sensors; the patient is then coupled to at least a portion of the sensor device by lying, sitting, leaning, standing on, or wearing the surface. Detecting a first mechanical signal with a first piezoelectric sensor of the sensor device and a second mechanical signal with a second piezoelectric sensor of the sensor device, the first and second mechanical signals being converted into first and second digital signals, and comparing the first and second digital signals; finally, patient data is provided to the user based on the comparison of the digital signals.

The sensor device may be provided on any suitable surface, such as a hospital bed, a bed, an operating room table, an examination table, an operating chair or table, a dentist chair, a hospital chair (hospital chair), a chair seat, a chair back, a wheelchair, a crib, a stretcher, a gurney, or any other surface. In some embodiments, the sensor device may be provided as some sort of wearable device. Typically, the sensor device comprises, in addition to the at least two piezoelectric sensors, a plane with means for bonding the piezoelectric sensors to the plane. Thus, coupling the patient with the sensor device may comprise merely laying the patient on a bed provided with the device. In other embodiments, coupling the patient to the sensor device may include allowing the patient to sit on a chair in which the device is provided, or to sit on a chair seat, lean against a chair back, or both. Sometimes, the patient will be coupled to the sensor by at least one layer of clothing, bedding or other material.

In various embodiments, any number of mechanical signals may be detected by the piezoelectric sensor. For example, in one embodiment, stress signals, thermal signals, and/or acoustic signals may be detected. Such signals may be detected in any particular environment, whether by patient or non-patient. For example, the patient may be a patient in a general care area of a hospital, a long-term care facility (long-term care facility), or a nursing home. In another embodiment, the patient may be a patient undergoing a surgical procedure under conscious sedation.

The sensor device may comprise any suitable number of piezoelectric sensors. In various embodiments, the sensor device may include 2, 4, 6, 8, 16, 18, 32, or 36 piezoelectric sensors. Any number, combination, style, size, shape or type of piezoelectric sensors are contemplated. When more than two sensors are included in the sensor device, any combination of sensors may be used to detect the mechanical signal, and any combination of signals from the various sensors may be compared to provide patient data to the user. For example, a method may include detecting third and fourth mechanical signals converted to third and fourth digital signals, and comparing the first, second, third, and fourth digital signals.

Comparing the digital signals may include comparing the presence or absence of one signal with the presence or absence of another signal. For example, if there is a positive mechanical signal in one sensor and no signal in another sensor, this can be used to provide information on the position of the patient on the sensor device. Comparing the digital signals may further comprise comparing the quantity, quality and/or information content of the first signal with the quantity, quality and/or information content of the second signal. For example, a mechanical signal from a sensor positioned near the chest of the patient, which corresponds to a heart beat signal, may have a higher quality than a heart beat signal from a sensor positioned near the right foot of the patient. In one embodiment, the method further comprises selecting one of the other signals to provide data to the user based on which signal has the highest quality or information content. Optionally, the method may also include determining whether the patient is on the surface based on a comparison of the two or more signals. The method may further comprise determining the position of the patient on the surface.

In one embodiment, the method includes dividing the digital signals into at least two groups, which correspond to at least two patient parameters. For example, the parameters may include, but are not limited to, patient motion on the sensor device, patient position on the sensor device, patient breathing rate, and/or patient heart rate. Optionally, the method may include comparing at least one of the digital signals to at least one predetermined threshold. Such thresholds may include any patient parameter or combination of parameters. For example, one or more digital signals of the patient's body motion may be compared to at least one of the amount of body minimum motion and the amount of body maximum motion. In another embodiment, the one or more breathing rate digital signals may be compared to at least one of a minimum breathing rate and a maximum breathing rate. In yet another embodiment, the one or more heart rate digital signals may be compared to at least one minimum heart rate. In other embodiments, other signals or combinations of signals may be compared to multiple thresholds. Where thresholds are used, providing patient data to the user may include activating an alarm when at least one of the digital signals does not meet at least one of the predetermined thresholds. In other embodiments, an alarm may be activated if a negative trend is detected in one or more patient parameters. For example, a heart beat signal may be compared to an earlier heart beat signal and a breathing signal may be compared to an earlier breathing signal, and an alarm activated if a negative heart beat trend, a negative breathing trend, or some combination thereof occurs.

Patient data may be provided to one or more users in any suitable form. For example, providing patient data may include activating an alarm based on a comparison of the digital signals. In some embodiments, providing patient data may further comprise providing a position of the patient on the surface. In other embodiments, providing patient data to the user may include providing a patient's breathing rate, a patient's heart rate, or both. In some embodiments, multiple patients may be monitored simultaneously, such as in a general care area of a hospital, in a long-term care facility, or in a nursing home, and providing patient data includes providing data at a common location. For example, the common location may include, but is not limited to, a nursing station, a display monitor, a digital pager, a wireless handheld device, an existing nurse call station, and/or a monitoring room.

In another aspect, a method of passively monitoring physiology of a plurality of patients includes: first, a plurality of sensor devices, each having at least two piezoelectric sensors, are arranged on a plurality of surfaces. Each patient is coupled to at least a portion of one of the sensors by having each patient lie, sit, lean, stand on or wear one of the surfaces. At least two piezoelectric sensors on each sensor device are used to detect at least one mechanical signal and convert the detected mechanical signal into a digital signal. Then for each patient, comparing the digital signals corresponding to the at least two piezoelectric sensors; and providing patient data corresponding to a plurality of patients to a user at a central location based on the comparison of the digital signals.

In yet another aspect, an apparatus for passively monitoring a patient includes: a surface for engaging a patient; and at least two piezoelectric sensors associated with the surface for detecting at least one mechanical signal from the patient. A processor is coupled to the piezoelectric sensors for converting the at least one mechanical signal to at least one digital signal and for comparing the digital signals corresponding to each of the at least two piezoelectric sensors to provide data about the patient. A first connector connects the piezoelectric sensor to the processor and a second connector is provided for connecting the processor to devices for providing patient data to a user.

In some embodiments, the surface comprises a flat pad. For example, the flat pad may include at least one layer of resilient foam material. The piezoelectric sensors may be arranged in any suitable form along the surface to enable monitoring of the patient. The surface may have any suitable dimensions. In one embodiment, the surface is sized to be positioned on at least one of a chair seat and a chair back to monitor a patient undergoing a surgical procedure under conscious sedation. In other embodiments, the surface is sized to be placed on a crib or bed for monitoring an infant. In a further embodiment, the surface is sized to be placed on a bed for monitoring a patient in a hospital or nursing home.

Optionally, the device may further comprise a housing (skin) for receiving at least a portion of the surface to provide a protective layer between the surface and the patient. Typically, such a cover will be waterproof. Sometimes, the housing includes at least one connector for connecting said housing to the surface. And the surface must be coupled to the connector in order to monitor at least one mechanical signal of the patient. In some embodiments, the enclosure may be discarded after being used to monitor a patient.

The piezoelectric sensor may be made of any suitable material. For example, in some embodiments, the sensor includes one or more of a polyvinylidene fluoride membrane, a polyvinylidene cable, a piezoelectric ceramic disc (piezo ceramic discs), and a piezoelectric foam. The sensor device may be disposed on a flat surface of a bed and at least one mechanical signal of the patient may be monitored while the patient is lying on the surface. The mechanical signal may include any suitable signal or combination of signals, but in one embodiment includes a stress signal, a thermal signal, and/or an acoustic signal.

The first and second connectors may comprise any suitable connectors. In some embodiments, the two connectors are wired connectors, while in some embodiments they are both wireless, and in other embodiments the connectors comprise a combination of wired and wireless connectors. In one embodiment, the first connector may comprise means for: the device is used for detecting the type of sensor device connected to the processor through the first connector or for detecting the number of times the sensor has been used. For example, when the sensor device is connected to the processor through the first connector, the connector may detect whether the device is of a type compatible with the processor and/or how many times the device has been used. In some embodiments, the first connector is thereafter capable of activating the sensor device based on one or more criteria that have been detected.

In general, the processor may provide the patient data in any suitable form or forms. For example, patient data may be provided in the form of an activated alarm. In one embodiment, the processor activates the alarm if the comparison of the data signals indicates that the patient is not moving on the surface, that the patient is not in contact with the surface, or that the patient is moving excessively on the surface. In another embodiment, the processor activates the alarm if the patient's heart rate falls below a predetermined minimum heart rate or rises above a predetermined maximum heart rate. In yet another embodiment, the processor activates the alarm if the patient's breathing rate falls below a predetermined minimum breathing rate or rises above a predetermined maximum breathing rate. In other embodiments, the processor activates an alarm if a combination of any of the above occurs. In some embodiments, an alert is issued if a certain negative trend occurs, such as a negative (negative) heart rate, respiratory rate, patient movement, or other trend, or a combination of trends. In some embodiments, the processor also provides patient data in the form of the patient's respiratory rate, heart rate, or both.

In yet another aspect, a disposable cover for receiving at least a portion of a sensor device for passively monitoring a patient includes a planar surface for coupling with the patient and at least one housing for receiving at least a portion of the sensor device. In some embodiments, the cover is waterproof. In some embodiments, the housing includes at least one connector for removably connecting the housing to a device for passively monitoring a physiological condition, and connecting the housing to the device enables the device to be activated to monitor the physiological condition of the patient.

In another aspect, a system for passively monitoring a plurality of patients includes a plurality of sensor devices, each sensor device having a surface for engaging a patient and at least two piezoelectric sensors coupled to the surface for detecting at least one mechanical signal from the patient. The system further includes a plurality of processors, each processor coupled to one of the sensor devices for converting the at least one mechanical signal into at least one digital signal and for comparing the digital signals corresponding to each of the at least two piezoelectric sensors to provide data about the patient. Finally, the system includes at least one connector coupled to each of the processors for connecting each processor to a common device for providing patient data for a plurality of patients to a user. In various embodiments, such a system may include any one or more of the features of the apparatus described above.

Drawings

FIG. 1 is a diagram of a passive patient monitoring system according to an embodiment of the present invention.

FIG. 1A is a diagram of a passive multi-patient monitoring system according to an embodiment of the present invention.

Fig. 2 is a front view of a sensor device according to an embodiment of the present invention.

Fig. 2A-2F are schematic front views of sensor devices according to various embodiments of the present invention.

Fig. 3A is a front view of a piezoelectric sensor and transmitter for use in a sensor device, in accordance with an embodiment of the present invention.

Fig. 3B is a front view of a surface for mounting two piezoelectric sensors as shown in fig. 3A, in accordance with an embodiment of the present invention.

Fig. 3C is a front view of a complete sensor assembly including a housing for housing the surface and piezoelectric sensors of fig. 3A and 3B.

Fig. 4 is a block diagram illustrating elements of a processor for processing signals in accordance with embodiments of the present invention.

FIG. 5 is a flow chart illustrating a method for passively monitoring a patient in accordance with an embodiment of the present invention.

Detailed Description

Generally, the present invention provides devices, systems and methods for passively monitoring one or more patients, infants, nursing home nursing staff or any other individual or group of people in need of monitoring. The apparatus generally comprises: a sensor device having at least two piezoelectric sensors for detecting one or more mechanical signals from the patient; a processor coupled to the sensor device for processing the mechanical signals to provide patient data; and a device for connecting the processor and the device to provide data to a user. In some systems, multiple sensor devices and multiple processors may be used to monitor multiple patients simultaneously, and each processor may be connected to a common facility to provide patient data to the user.

Generally, the method includes providing a sensor device on a surface, coupling a patient to the device by allowing the patient to lie, sit, lean, stand on, or wear the surface; detecting at least one mechanical signal with a first piezoelectric sensor; processing the signal; and provides data to the user based on the processed signals. The phrase "passive patient monitoring" or simply "passive monitoring" generally refers to such concepts: the various methods and devices of the present invention generally provide for monitoring a patient by allowing the patient to lie, sit, lean, stand or the like on a surface on which the sensor device is disposed, or possibly comfortably wear the sensor device. Such monitoring is "passive" in that it does not require direct attachment of one or more devices to the patient's body. In fact, it is often possible to monitor a patient using the device, method and/or system of the present invention without the patient even being aware of the presence of the monitoring device. In general, the sensor devices of the present invention may be placed under one or more layers of sheets or other bedding and are capable of sensing patient parameters through the bedding as well as through a patient's gown or other clothing. Thus, the methods and apparatus of the present invention may sometimes be referred to as "invisible" and passive because they may be hidden under bedding, within a seat cushion, or the like.

In general, any number or combination of parameters relating to a patient or other person being monitored may be measured. For example, in one embodiment, the position and/or movement of the patient on the patient's bed is monitored. Alternatively, the patient's breathing rate and/or heart rate may also be monitored. Other parameters, such as blood pressure, Cardiac Output, body temperature and temperature changes, and/or the like, may also be suitably detected and monitored in various embodiments. Any of the above patient parameters may be monitored in any suitable person or group of persons in any suitable particular environment. For example, multiple patients in a general care area of a hospital, patients undergoing a surgical procedure under conscious sedation, patients in an emergency or operating room, nursing home or long-term care patients, sleeping infants, or even home healthcare patients may be monitored. Similarly, a person may be monitored while lying on a hospital bed, a general bed, an operating table or a stretcher or wheelchair, while sitting on a chair or wheelchair, or while lying, leaning or standing on any other suitable surface. Thus, while the following description often focuses on an exemplary embodiment of monitoring a patient on a general care floor or ward of a hospital, this description is for exemplary purposes only and should not be construed as limiting the scope of the invention described in the claims.

The patient monitoring data may be provided to the user in any suitable form. In some embodiments, the data is used to activate an alarm. For example, if the detected patient signal is above or below a predetermined threshold or represents a negative trend, the alarm may be activated if a combination of patient parameters (e.g., respiratory rate, heart rate, and body motion) meets a predetermined negative trend or the like. In other embodiments, the data may be provided on a monitor for reading by a healthcare worker or other user. In other embodiments, the data may be used to activate an alarm and displayed on a monitor. An alarm, display monitor or the like may provide information to the user about one patient or about multiple patients. For example, an alarm and/or display monitor may be placed on a common nursing station on a hospital ward to provide information about patients throughout the ward to one or more nurses at the nursing station. In other embodiments, the data may be provided at the patient's bedside, or may be provided at the bedside and at a central location. Any other suitable form of providing physiological data to one or more users is contemplated, such as providing physiological data through one or more digital pagers, wireless handheld devices, or the like. For the purposes of this patent application, the phrase "data display device" or "display device" refers to any device for providing physiological data to a user, such as an alarm, monitor, alarm and monitor, or any other suitable device.

Also, the devices, systems, and methods of the present invention may be used in any suitable specific environment for patient care, research, veterinary medicine, and/or the like. In one embodiment, multiple patients on a general care floor of a hospital are passively monitored simultaneously to provide continuous monitoring without the need for a healthcare professional to be present at the patient's bedside. Such monitoring systems may be used on any suitable floor, ward or area of a hospital or clinic. In another embodiment, the physiological condition of a patient undergoing a surgical procedure under conscious sedation is monitored. The apparatus, system and method of the present invention may be used to monitor sleeping infants susceptible to sudden infant death syndrome, as well as personnel in nursing homes, long term nursing homes or skilled care facilities, patients transported in emergency medical facilities, home care patients or other suitable patients or non-patients. Furthermore, various embodiments of the present invention may be added to existing patient monitoring systems and/or used with other compatible monitoring systems, such as original equipment manufacturer subsystems. For example, one embodiment may include a plurality of sensor devices and a plurality of processors, the latter of which are all connected to an existing nurse call station system (null call station) to provide patient data to one or more nurses at a common location.

Referring now to fig. 1, a system 100 for passive patient monitoring suitably includes a sensor device 102 having at least two piezoelectric sensors 202 coupled to a processor 104, which is in turn coupled to a data display device 106 for providing physiological data to a user. In general, the sensor 102 can be connected to the processor 104 by any suitable connector 110 (or connectors), such as a cable, wire, wireless transmitter, or the like. Similarly, any suitable connector 108 may be used to connect the processor 104 with the data display device 106. Any given embodiment may include multiple sensors 102, multiple processors 104, and/or multiple display devices 106. For example, multiple patients may be monitored simultaneously, each patient corresponding to a separate sensor device 102. In some embodiments, each sensor device 102 is coupled to its own, independent processor 104, while in other embodiments, multiple sensor devices 102 may be coupled to a common processor 104. In further embodiments, a portion of the processor 104 may include a plurality of separate units for each sensor, while another portion of the processor 104 may include one central unit, such as a central computer. Similarly, the display device 106 may include a common display monitor, alarm, or the like, but may alternatively include multiple alarms, displays, digital pagers, wireless devices, or the like. Thus, various embodiments of the system 100 may include a sensor device 102, a processor 104, and a display device 106, but may optionally include a number of one or more of these components. The connectors 108, 110 may similarly be provided as single or multiple components in various embodiments.

Some embodiments of the invention are provided as part of the system 100 shown in fig. 1. For example, in some embodiments, the user is provided with the sensor device 102 alone, for example, if the user already has one or both of the processor 104 and the display device 106, and a compatible processor and display device. Another embodiment of the present invention includes a sensor device 102 and an attached processor 104. The attached processor 104, which may be implemented in software or hardware, for example, may be attached to an existing computer, bedside monitor, or the like, for processing data received from the sensor device 102. Thus, although in one embodiment, the system 100 includes the sensor device 102, the processor 104, the display device 106, and the connectors 108, 110, other embodiments may include fewer elements or additional elements without departing from the scope of the invention. Each of the various elements of the present invention illustrated in fig. 1 will be described in more detail below.

Referring now to FIG. 1A, a multiple patient monitoring system 101 includes any number of sensor devices 102a-102n, any number of processors 104a-104n, a common display device 106 such as an alarm, monitor, or the like, and any number of connectors 110a-110n and 108a-108n in a suitable manner. In other embodiments, multiple sensors 102a-102n may be coupled to a common processor, and the processor may in turn be coupled to the display device 106. In further embodiments, the one or more processors may transmit data to multiple display devices, such as to multiple digital pagers, digital handheld devices, multiple monitors, or the like. Any combination of sensor devices 102a-102n, processors 104a-104n, connectors 108a-108n and 110a-110n, and display device 106 are contemplated within the scope of the present invention.

The connectors 108a-108n, 110a-110n may include any suitable means for connecting the sensor devices 102a-102n to the processors 104a-104n and for connecting the processors 104a-104n to the display device 106. In some embodiments, for example, the connectors comprise wired connections, while in other embodiments, one or more of the connectors are wireless. For example, the connectors 110a-110n between the sensor devices 102a-102n and the processors 104a-104n may be wireless, while the other connectors 108a-108n may include wires. In one embodiment, connectors 110a-110n comprise a "smart connector" device. The smart connector may include a microchip or any other suitable data carrying or processing device and may be used to ensure compatibility between the sensor device and the processor. For example, when the sensor 102 is connected to the processor 104 through the smart connector 110, the smart connector can detect what type of sensor device 102 has been connected to the processor 104, how many times the sensor device 102 has been used, whether the sensor device 102 is compatible with the processor 104, or the like. Such smart connectors may include wired connections, have complementary plugs, or any other suitable connector. However, it should be understood that any connection means may be used to connect the various elements of the present invention.

Referring now to fig. 2, the sensor device 102 generally includes two or more piezoelectric sensors 202 disposed along a surface 212 to enable the sensors to be coupled to a patient in a convenient and passive manner. Each sensor 202 may be of any size, shape, configuration, material, etc. Generally, each sensor 202 comprises a piezoelectric material. In many embodiments, the material used is polyvinylidene fluoride (PVDF), but any piezoelectric material or combination of materials may be used, including but not limited to PVDF film, PVDF cable, piezoelectric ceramic disks (piezoelectric ceramic disks), and/or piezoelectric foam (piezoelectric cfoam). The piezoelectric material of the present invention may have any suitable shape, size and configuration. For example, in some embodiments, a thin PVDF film is used, either alone or in combination with PVDF cable. In some embodiments, the sensor 202 comprises a rectangular flat sheet of PVDF film. In other embodiments, the sensors 202 may include: circular, triangular, square, or any other shape PVDF membrane; a flat piezo-ceramic material of circular or any other suitable shape, or any other suitable material. For example, in one embodiment, each sensor 202 is paper thin or thinner and has a width of about 6 inches and a length of about 9 inches. In other embodiments, each sensor may be larger, may be only a few millimeters in width and length, or may even be on the nanometer scale.

Referring now to FIGS. 2A-2F, several embodiments of sensor devices 102A-102F are shown, each having a different configuration of sensors. In FIG. 2A, two flat rectangular PVDF film sensors 218 are included. In FIG. 2B, three PVDF film sensors 218 are used in conjunction with PVDF cable 220. In fig. 2C, PVDF cable 220 is used alone in a zigzag configuration, which may include one cable or multiple cables. In fig. 2D, a plurality of piezoceramic disks 230 are used. In FIG. 2E, the PVDF film sensors 218, 222 are used in a pattern wherein the density of the sensors 222 is higher in one area of the device and lower in the other area of the device 218. This may be advantageous, for example, when a higher density of sensors is placed at locations where the patient may be more intense in measuring intensity, such as directly under the patient's chest to monitor heart rate and signals related to respiratory rate. Finally, in fig. 217, two piezoelectric foam sensors 240 are used. Thus, it will be clearly understood that any suitable combination and configuration of sensors may be used.

Referring again to fig. 2, the piezoelectric sensor 202 generally acts as a strain gauge sensor to detect changes in stress acting on the sensor 202. The detected stress changes can then be converted into data useful for patient monitoring purposes. The weight of the patient acting on one sensor 202 may be measured as the stress acting on one sensor and compared to similar measurements from one or more other sensors 202 on the same sensor device 102 to determine where the patient is located on the device, whether the patient is moving, and/or the like. The expansion of the patient's lungs or the beating of the patient's heart during inspiration can stress one or more sensor devices 202 placed under or near the patient's chest. The sensors 202 detect this change in stress, and the detected change can be processed to determine respiratory rate, heart rate, body movement, body position, and the like. A variety of other possible measurements, some of which are described below, can be derived from the information collected by the sensors 202. For a further description of the pressure sensing capability of piezoelectric materials, reference may be made to U.S. patent application serial No. 09/662,006 entitled "Passive physical Monitoring Systems and Methods," filed by the present inventors on 9/2000, the entire disclosure of which is incorporated herein by reference.

As described above, the apparatus of the present invention generally includes a surface 212, and two or more piezoelectric sensors 202. Both the surface 212 and the sensor 202 may have any suitable configuration. For example, in some embodiments, surface 212 simply comprises one or more pieces of resilient foam, plastic, paper, or any other suitable material. In other embodiments, surface 212 comprises two layers of foam material that are attached together with an adhesive or in any other suitable manner. The sensor 202 may be bonded to the surface 212 by an adhesive, by sandwiching the sensor 202 between two layers of the surface 212 and by means of an adhesive, or by any other suitable means. Accordingly, the following description is provided to illustrate one embodiment of the invention and should not be construed as limiting the scope of the invention as set forth in the claims.

In some embodiments, the sensor device 102 includes a surface 212 having a casing 210 with pockets 208a-208h for receiving the piezoelectric sensors 202a-202h in the casing 210. As shown in FIG. 2, each piezoelectric sensor 202a-202h is coupled to a transmitter 204a-204h, which may comprise an electrical lead or wire, as shown, or alternatively a wireless transmitter or the like. Finally, in some embodiments, a plurality of sensor transmitters 204 may be connected with the sensor transmitter connector 206. Sensor transmitter connector 206 generally serves as a common connector for connecting piezoelectric transmitters 204a-204h to processor 104. In other embodiments, any other suitable means for connecting the piezoelectric sensor to the processor 104 is contemplated. Such connections may include wireless connections via radio frequency, microwave, infrared, or any other suitable wireless transmission means, may include multiple wires, may include common wires leading from a location within surface 212 where individual transmitters 204a-204h are connected, or the like.

Any suitable size, shape, thickness, and overall configuration of surface 212, casing 210, pockets 208a-208h, and sensors 202a-202h may be used. For example, some embodiments have only two piezoelectric sensors 202 and two corresponding pockets 208, while other embodiments have 4, 8 (as in fig. 2), 16, 32, or any other suitable number of sensors 202 and pockets 208. One arrangement of sensors 202 on surface 212 may be referred to as an "array" or a "Passive Sensor Array (PSA)". Such passive sensor arrays generally include grid-like sensors 202 located on a surface. Such a grid may include a plurality of rectangular PVDF film sensors 202, as shown in FIG. 2, or any other shape, size, or type of sensor, as shown in FIGS. 2A-2F. The PSA may contain any suitable number of rows or columns of sensors 202, and some forms may have advantages in certain specific circumstances. For example, in embodiments where the sensor 102 is designed for use on a chair seat or back, it may be desirable to have only two 202 sensors on the surface 212. In another embodiment, it may be advantageous for a sensor device 102 that may be designed for use with a crib to have two columns of four sensors each. In yet another embodiment, 3 columns of 8 sensors 202 may each be used in a hospital bed configuration. Any number of rows, columns, and sensors 202 may be used in any given embodiment. In some embodiments, it may be advantageous to use PVDF cable, either alone or with a PVDF film. For example, in one embodiment, PVDF cable may be used around surface 212 to detect patient movement at the edge of the bed.

In one embodiment, each sensor 202 is contained in a separate pocket 208, although other configurations and combinations are contemplated. For example, the sensor 202 may simply be sandwiched between two layers of the surface 212 and may be bonded to the surface 212 by an adhesive. The casing 210 may include a plurality of pockets 208a-208h or sleeves, each for housing one sensor 202, or the casing 210 may include one or more larger pockets for housing a plurality of sensors 202. Although any size can be used, in one embodiment as shown in FIG. 2, 8 sensors are arranged along a surface having dimensions of about 32 inches by 24 inches. In such an embodiment, each sensor may have dimensions of about 9 inches by about 6 inches. It should be emphasized that any configuration, form, size, and the like of sensor 202 and surface 212 are within the contemplation of the present invention.

Surface 212, jacket 210, and bags 208a-208h may be made of any suitable material or combination of materials, such as, but not limited to, neoprene, plastic, polypropylene, natural or synthetic fibers, Poron, Scappa, PVC, foam, Tyvek, and the like. In one embodiment, surface 212, jacket 210, and pockets 208a-208h comprise a resilient foam material such as neoprene. For example, a layer of neoprene may be used for surface 212, and another layer may be used to form bags 202a-202 h. In another embodiment, two layers of neoprene are sandwiched together with the sensor between them, and an adhesive is used to bond the two layers together and the sensor to the neoprene. Such neoprene surface 212 and cover 210 may form a flat, mat-like device. And in some embodiments, the neoprene material may provide cushion-like comfort when the sensor device 102 is placed on a bed, chair, or the like, under a patient. In some embodiments, surface 212 may also contain additional padding of neoprene or any other suitable material to improve the comfort of a patient lying or otherwise exerting gravity on surface 212. Accordingly, the surface 212 may sometimes be referred to generally as a "pad" or "sensor pad".

The pockets 208a-208h may have any suitable shape to hold or house the sensors 202a-202 h. As shown in fig. 2, some of the pockets 208 may be provided as a layer of neoprene or other material, attached to the surface 212, and having an opening to allow the sensor 202 to be placed in the pocket 208. The opening may also allow a sensor transmitter 204, such as a wire, flexible connector, or the like, to pass through the outer sleeve 210 and connect to the sensor transmitter connector 206. In some cases, as shown in fig. 2, each pocket 208 may have an opening through which the sensor 202 can pass, and an opening through which the sensor transmitter 204 can pass. In some embodiments, the width of the opening is less than the width of the sensor 202, such that the sensor 202 can be bent or folded to fit within the pocket 208, and then can be laid flat within the pocket 208, so that generally the sensor 202 will remain in place within the pocket 208. In some embodiments, the opening may enable the sensor 202 to be reused when the surface 212 is discarded. Alternatively, and more preferably, the sensor 202 is placed in the pocket 208 with an opening at the time of manufacture, but the opening is permanently sealed after the sensor 202 is placed. In other embodiments, there are no openings. Any other suitable configuration of bag may be used.

In some embodiments, the plurality of sensor transmitters 204 may be connected to or coupled with one or more sensor transmitter connectors 206. The sensor transmitter connector 206 may be placed anywhere on or around the surface 212 and is generally used to more conveniently couple the sensor transmitter 204 to the processor 104 or other device. Any other suitable means for coupling the one or more sensor transmitters 204 to the processor may optionally be used.

Referring now to fig. 3A, the sensor 202 and transmitter 204 are shown as being independent. Two or more bags 208a-208b may be used to couple two or more sensors 202a-202b and transmitters 204a-204b to a surface 212 having an outer sleeve 210, as shown in fig. 313. Referring to fig. 3C, some embodiments of sensor device 102 further include a housing 302 for covering or housing all or a portion of surface 212 and sensor 202. The outer cover 302 may have any suitable configuration and size, and may comprise any suitable material and combination of materials. For example, in one embodiment, the housing 302 includes an envelope-like structure having a first side 302a and a second side 302 b. In one embodiment, such a housing 302 may be opened or closed (curved arrows) along one edge by a connecting portion, thereby enabling the surface 212 and the sensor 202 to be placed in the housing 302. Another embodiment may include a similar cover 302 having two layers or sides 302a-302b joined along two or three edges to create a pocket or sleeve in which surface 212 and sensors 202 may be placed.

Although any suitable material or combination of materials may be used to fabricate the outer cover 302, one exemplary embodiment uses a material that has some degree of water resistance. For example, the outer cover may be made of foam, plastic, paper, nylon, PVC, fibrous materials, any combination thereof, or any other suitable material or combination of materials. In many patient care settings, it is advantageous to employ a waterproof housing 302 to protect the surface 212 and sensors 202 from urine, water, blood, or any other liquid that may be spilled on a patient's bed or chair and which may damage the unprotected surface 212 or sensors 202. Thus, the housing 302 generally protects the surface 212 and the sensors 202, thereby enabling their repeated use for multiple patients and increasing their useful life. For example, some surfaces 212 and sensors 202 may be used for up to 6 months or more. On the other hand, in some embodiments, the enclosure 302 may be disposable and used for only one patient, only one day, or the like.

To ensure proper use and/or prevent reuse of cover 302, some embodiments of cover 302 and surface 212 include complementary connectors (not shown) to create a connection between cover 302 and surface 212. Such a connector may be any suitable connection means, such as an electronic connection means, a circuit completed by the connection of complementary parts, or the like, and is generally designed to enable activation of the sensor device 102. Thus, in some embodiments, it may be desirable to couple the surface 212 to the housing 302 prior to using the sensor device 102 to monitor a patient. The housing 302 may activate or cause the device 102 to operate to monitor the patient. This binding/activation requirement may prevent reuse of the enclosure 302 between patients, which may help prevent transmission of infections between patients, prevent abuse of the sensor device 102, and increase the useful life of the sensor device 102.

As previously explained, surface 212, housing 210, sensors 202, and the like may have any suitable size, shape, and configuration. For example, in one embodiment, as shown in fig. 3B and 3C, the surface may have a length of about 16 inches and a width of about 12 inches. The outer jacket 210 may have a width 304 of about 10 inches and a length of about 14 inches. One bag 208a or 208b may have a length 304 of about 10 inches and a width 306 of about 7 inches. In this configuration, one sensor 202a or 202b may have dimensions of about 6 inches by about 9 inches. These are just a few exemplary dimensions, however, any suitable dimensions for surface 212, sensors 202, casing 210, pocket 208, and the like are contemplated.

Referring again to fig. 1, the sensor device 102 may be generally coupled to the processor 104. Processor 104 includes any suitable means for receiving mechanical signals detected by piezoelectric sensors 202 of sensor device 102 (or any other suitable sensor device) and processing these signals to provide patient data to one or more users. In some embodiments, the processor 104 includes a bedside unit that can be coupled to the sensor device 102 via one or more wired connections, wireless connections, or the like. In other embodiments, the processor may include a circuit board, a computer chip, a software program, and/or any other suitable processing means. Thus, in some embodiments, the processor 104 comprises a separate device that can be coupled to the sensor 102 for processing signals and providing data to the user. In yet other embodiments, processor 104 includes an additional device that may be used in conjunction with separately provided hardware, such as that provided by the original equipment 25 manufacturer.

Referring now to FIG. 4, an embodiment of an add-on processor 104 is shown, the add-on processor 104 being used with hardware such as a bedside monitoring unit or any other suitable hardware. In general, processor 104 includes any suitable means for processing the mechanical signals into usable patient data. For further description of the signal processing apparatus and method, reference may be made to U.S. patent application serial No. 09/662,006, which is incorporated herein by reference. In some embodiments, the processor 104 suitably includes an acquisition module 402 coupled to a processing module 404 and a power supply 440. The acquisition module may include a connector module 406, a shock protection module 408, a programmable variable gain differential amplifier module 410, an electromagnetic interference (EMI) filter module 412, an analog filter module 414, an analog-to-digital (AD) converter module 414, and a digital-to-analog converter module 416. It should be emphasized that in various embodiments, acquisition module 402 may include fewer components or additional components, and/or that various modules may be combined to produce fewer modules. In general, the acquisition module 402 acquires analog mechanical signals from the sensor device 102, filters the signals with one or more filtering devices, and converts the filtered signals to digital signals. Any means may be used for acquisition, filtering and conversion.

The processor 104 may also include a processing module 404. Processor module 404 may include a digital signal processor/central processing unit (DSP/CPU) module 418, a flash memory module 420, a static RAM module 422, a non-volatile memory module 424, a real-time clock module 426, a Joint Test Action Group (JTAG) emulator module 428, a digital input/output module 430, an analog-to-digital (AD) synchronous serial communication module 432, and an input/output asynchronous serial communication module 434 and glue logic (glue logic) Field Programmable Gate Array (FPGA) device 436. Also, various modules may be combined, omitted, or added without departing from the scope of the invention.

In some embodiments, the power supply 440 is coupled to the acquisition module 402 and the processing module 404 to provide power to the processor 104. The power source 440 may be any suitable form of power supply, such as a battery, connection to an external power source, and/or the like. Power supply 440 is not included in some embodiments. For example, in some embodiments, the acquisition module 402 and the processing module 404 can be configured to be used with existing hardware, which may already include a power source. This would occur, for example, in embodiments where the acquisition module 402 and/or the processing module 404 are provided in the form of one or more circuit boards, chips, or the like that are attached to a computer, bedside monitor, or other patient monitoring device. Therefore, it should again be emphasized that the processor 104 shown and described in FIG. 4 is merely an exemplary embodiment and should not be construed as limiting the scope of the invention in any way.

As briefly described above, the processor 104 typically receives one or more mechanical signals from the sensor device 102 and processes the signals to provide patient data to the user. For example, the processor may receive a mechanical signal in the form of a pressure change signal from the sensor device. Such signals are typically received by the processor through multi-channel circuitry, each channel corresponding to one piezoelectric sensor 202 of the sensor device 102. Filtering means, such as EMI filter module 412, analog filter module 414, filtering software, processing software, intelligent algorithms, and/or the like then filter the signal, for example, to remove background interference (noise) and the like. The signal is then converted to a digital signal by the AD converter module 416. The digital signal may then be processed by various means. In some embodiments, a Fast Fourier Transform (FFT) method may be used, as further described in U.S. patent application serial No. 09/662,006. In other embodiments, time domain analysis may be used. Still other embodiments may use a combination of these two approaches. At some point during signal processing, at least one type of signal is compared between the plurality of piezoelectric sensors 202 of the sensor device 102. For example, the mechanical pressure change signal may be compared between multiple sensors 202 on the sensor device 102. Such a comparison of signals may enable the processor 104 to provide patient data to the user, such as where the patient is located on the sensor device 102, whether the patient is moving on the sensor device 102, whether the patient is present on the sensor device 102, whether all movement of the patient has ceased or is below a predetermined level, and/or the like.

In some embodiments, the signals may be compared to enable the processor 104 to select a signal with the best fidelity, information content, or the like. For example, the signals may be compared and the signal related to respiration may be selected from the sensor 202 having the highest quality respiration signal. Similarly, the highest fidelity heart beat signal may be selected from the sensors 202 that detected the highest fidelity heart beat signal. It is also possible that one sensor 202 detects both the highest quality respiratory signal and the highest quality cardiac signal (or any two or more types of signals) and provides these signals as data to the user. The comparison between sensors 202 may also enable the processor to determine what portion of the mechanical signal is associated with a given physiological parameter. For example, a mechanical signal from a first sensor 202 located under the patient's chest will generally contain a stronger respiratory component than a mechanical signal from a second sensor 202 located under the patient's left foot. These signals may be compared to isolate and determine the respiratory signal. Also, such a method of processing signals, any of which may be suitably used by the processor 104, is more fully described in U.S. patent application serial No. 09/662,006, which is incorporated herein by reference.

In addition to filtering the signals and comparing the signals between the various sensors 202, the processor 104 may process the mechanical, analog signals received from the sensor devices 102 in any suitable form. For example, in some embodiments, the processor 104 compares a given signal or signals to one or more threshold levels and provides data to activate an alarm if the given signal is above or below the threshold. For example, thresholds for minimum and maximum amounts of patient movement on the hospital bed, thresholds for minimum or maximum breathing rate, thresholds for minimum or maximum heart rate, and/or the like may be stored in the processor 104. If the signal detected from the patient falls outside of one or more thresholds, the processor 104 can provide data to the user in the form of an alarm activation signal. In some embodiments, a combination of multiple thresholds may be set. For example, a minimum heart rate threshold may be specified such that if the patient's breathing rate is below the threshold and the patient's heart rate is below the heart rate threshold, only an alarm will be caused to activate. Any combination of such thresholds, alarm activation processes, and the like is contemplated. Also, for general care floors of a hospital or the like, one or more thresholds may be selected by the manufacturer of the processor 104 such that they are "hard wired" for all patients, or they may be adjustable by a nurse, physician or other user for each patient.

Further functions of the processor 104 may include processing the signals to provide respiratory rate and/or heart rate data. Such data may be provided in the form of respiration/minute, heart rate/minute, waveform signal data showing lines or waveform curves representative of respiration, heart beat and/or the like, or in any other form. The patient's motion or position may also be provided in any suitable form, such as amount of motion, position of motion, patient position on a hospital bed or chair, or the like. Other parameters, such as blood pressure, cardiac output, blood volume, tidal volume (respiratory tidal volume), body temperature and temperature changes, and/or the like, may also be measured and provided, as previously described.

Referring again to fig. 1, once the sensor device 102 detects one or more signals from the patient, and the processor 104 processes these signals to provide patient data, the data is typically provided to the user in some suitable form. In many embodiments, the processor 104 only provides data to one of the previously existing systems of the user. For example, in one embodiment, the processor 104 is coupled to an intranet or the Internet through an Ethernet connection. The user may then obtain the data via any computer or other device having an intranet or internet interface. In various embodiments, the processor 104 may also be capable of providing data for storage, display, and/or download at predetermined intervals, such as every 30 seconds, every minute, or similar time units, over days, weeks, or any other period of time. 30 may be downloaded to a computer, monitor, printer, portable data storage device, or any other suitable hardware or software unit. In another embodiment, the processor 104 provides the data in the form of an alarm that activates an existing alarm system, such as a hospital nurse call system. Such a system may be located at the bedside, outside each patient room, at a common nurse call station, and/or the like. In still other embodiments, the data may be provided by wireless transmission via one or more digital pagers or wireless handheld devices.

The processor 104 may include any suitable connector 108 for coupling the processor 104 to a device used by a user to obtain data. For example, the connector 108 may include a wired connection, a wireless connection, a connection to a computer network, an electronic connection to an alarm system, or any other suitable connection. Thus, although the system 100 of FIG. 1 includes a display device 106, it should be understood that the systems, devices, and methods of the present invention may suitably include a sensor device 102 and a processor device 104, and may provide data to one or more existing display devices, alarms, pagers, or other systems.

In other embodiments, the display device 106 may be provided or housed in a separate device or in the same device in which the processor 104 is housed. For example, a bedside box-like unit (bedside box-like unit) coupled to the sensor device 102 may include the processor 104 and the display device 106, the display device 106 including an alarm and a screen for viewing physiological data. Alternatively, in other embodiments, the processor 104 and the display device 106 may be separate parts. For example, the processor 104 may be a bedside unit and may transmit data to one or more central and/or remote display devices 106. As discussed briefly above, the display device 106 may include one or more devices for providing physiological data regarding one or more patients to a user. In some embodiments, the display device 106 includes a bedside alarm that sounds when the patient reaches a predetermined physiological threshold. In another embodiment, the display device 106 includes an alarm and a display monitor, or screen for viewing physiological data about one or more patients.

The display device 106 may be placed in any suitable location. For example, some display devices 106 are located at the patient's bedside or in the patient's room. While in other embodiments the display device is disposed in a common location, such as a nurse station or central monitoring station on a hospital floor (hospital floor) within a hospital ward or similar environment. In yet another embodiment, the display device 106 may comprise one or more mobile, wireless devices, such as a digital pager or wireless handheld device, that enable a nurse, physician, or other user to remotely receive patient physiological data. In still other embodiments, the patient data may be obtained on a personal computer, handheld device, or similar device via a secure connection to the internet. Thus, any form, number, or combination of display devices 106 is contemplated within the scope of the present invention.

Referring now to fig. 5, in accordance with one embodiment of the present invention, a method 500 suitably includes: 502, coupling a patient to a sensor device; 504, detecting at least one mechanical signal of the patient; processing 506 the mechanical signals into patient data; and 508, providing the patient data to the user. Generally, prior to coupling a patient to a sensor device, at 502, the sensor device 102 is disposed on a surface. As mentioned above, the surface may comprise any suitable surface, such as, but not limited to, a hospital bed, a general bed, an operating room table, an examination table in a doctor's office, a procedure chair or table for performing procedures under conscious sedation, a dentist's chair, a hospital chair or other chair, a chair seat and/or back, a wheelchair, a crib, a stretcher or gurney, or the like. In other embodiments, the surface may be in the form of a surgical gown, sleeveless jacket, belt, or the like, and may be wearable. Providing the sensor device 102 on a surface may include simply placing the sensor device 102 on the surface, or may include integrating the sensor device 102 into the surface. For example, the sensor device 102 may be built into a hospital bed surface or a chair seat or back. In some embodiments, the sensor device 102 may be disposed under one or more layers of material, such as the sensor device being disposed under one or more sheets on a bed, being disposed within an envelope-like or quilt-like covering on a bed, being disposed under a cushion of a seat, or the like. Accordingly, sensor device 102 may be disposed on any suitable surface in any suitable manner without departing from the scope of the present disclosure.

Coupling the patient to the sensor device 502 generally includes enabling the patient to lie, sit, lean on, or otherwise exert gravity or pressure on the surface on which the sensor device 102 has been disposed. Such lying, sitting, leaning, or the like includes a component of "passive monitoring" because the patient is not even aware of the presence of the sensor device 102, and because there is no need to secure the sensor device 102 to the patient. This is in marked contrast to currently available devices, such as blood pressure cuffs, pulse oximetry sensors, nasal cannulae, ECGs and the like, all of which require active, direct securement of one or more devices to the patient.

Sensing the mechanical signal 504 generally includes sensing at least one mechanical signal with at least one piezoelectric sensor of the sensor device 102. In general, the detected signal may include a pressure signal, a temperature signal, an acoustic signal, or any other suitable mechanical signal. Sensor 202 typically detects changes in any given mechanical parameter, but in some embodiments may detect an absolute mechanical signal. The signal detected by the sensor 202 may include a positive signal (positive), or an absence of a signal (absence). For example, if a positive pressure change signal is detected in one sensor 202 of the sensor device 102 and no pressure change signal is detected in another sensor 202 of the sensor device 102, this may indicate that the patient is positioned on the previous sensor 202 and not on the next sensor 202; it may also indicate that the former sensor 202 detected the patient's respiratory rate or heart rate, while the latter sensor 202 did not; and/or the like. Thus, in some embodiments, a first sensor may detect at least one mechanical signal, a second sensor may detect at least one mechanical signal, and the detected signals may be compared. If the first sensor, the second sensor, or both do not actually detect a signal, then this lack of signal may be compared between the sensors to provide data to the user.

506, process the mechanical signal, as has been described in detail above. Generally, such processing 506 includes at least converting the mechanical signal to a digital signal and comparing the signal between at least two piezoelectric sensors 202 of the sensor 102. Processing 506 also includes processing the mechanical signal into data that can be provided to a user. As already described above 508, patient data is provided to the user. The data may be provided in the form of an activated alarm based on threshold criteria, such as patient motion, respiratory rate, and/or heart rate criteria. The data may also be provided as quantitative or qualitative patient motion or position data, respiratory rate data, heart rate, or the like.

While the present invention has been fully described above with respect to various exemplary embodiments, it should be understood that the description of the embodiments provided is merely exemplary and should not be taken as limiting the scope of the invention as set forth in the appended claims. Additions or modifications to any embodiment described and other embodiments are considered to be within the scope of the present invention.

Claims (87)

1. A method of passively monitoring at least one patient, the method comprising:

providing a sensor device on a surface, the sensor device having at least two piezoelectric sensors;

coupling a patient and at least a portion of the sensor device by the patient lying, sitting, leaning, standing on, or wearing the surface;

detecting a first mechanical signal with a first piezoelectric sensor of the sensor device;

detecting a second mechanical signal with a second piezoelectric sensor of the sensor device;

converting the first and second mechanical signals into first and second digital signals;

comparing the first and second digital signals; and

providing patient data to a user based on the comparison of the digital signals.

2. The method of claim 1, wherein the sensor device is disposed on a surface selected from the group consisting of: hospital beds, operating room tables, examination tables, operating chairs or tables, dentists' chairs, hospital chairs, chair seats, chair backs, wheelchairs, cribs, stretchers and gurneys.

3. The method of claim 1, wherein said sensor device further comprises a planar surface having means for coupling said at least two piezoelectric sensors to said planar 3 surface.

4. The method of claim 1, wherein coupling the patient with the sensor device comprises: the patient is allowed to lie on a bed on which the device is arranged.

5. The method of claim 1, wherein coupling the patient with the sensor device comprises: the patient is seated on a chair on which the device is arranged.

6. The method of claim 1, wherein coupling comprises: the patient is coupled to the sensor by at least one layer of clothing, bedding or other material.

7. The method of claim 1, wherein detecting the first and second mechanical signals comprises: at least one of a stress signal, a thermal signal, and an acoustic signal is detected.

8. The method of claim 1, wherein detecting the first and second mechanical signals comprises: signals are detected from patients in general care areas, long term care homes or nursing homes of a hospital.

9. The method of claim 1, wherein detecting the first and second mechanical signals comprises: signals are detected from a patient undergoing a surgical procedure under conscious sedation.

10. The method of claim 1, further comprising:

detecting third and fourth mechanical signals with third and fourth piezoelectric 3 sensors;

converting the third and fourth mechanical signals into third and fourth digital signals; and

the first, second, third and fourth digital signals are compared.

11. The method of claim 1, wherein comparing the digital signals comprises: comparing the presence or absence of the first signal with the presence or absence of the second signal.

12. The method of claim 11, wherein comparing the digital signals further comprises: comparing the quality of the first signal to the quality of the second signal.

13. The method of claim 12, further comprising: based on which signal has the best quality, either the first signal or the second signal is selected to be provided as data to the user.

14. The method of claim 11, further comprising: determining whether the patient is on or off the surface based on a comparison of the first signal and the second signal.

15. The method of claim 14, further comprising: determining a location of the patient on the surface.

16. The method of claim 1, further comprising: the digital signals are divided into at least two groups corresponding to at least two patient parameters.

17. The method of claim 16, wherein the at least two parameters are selected from the group consisting of: patient movement on the sensor device, patient position on the sensor device, patient breathing rate, and patient heart rate.

18. The method of claim 1, further comprising: comparing at least one of the digital signals with at least one preset threshold value.

19. The method of claim 18, wherein comparing at least one of the digital signals to the predetermined threshold comprises: comparing the at least one body movement digital signal with at least one of a minimum amount of body movement and a maximum amount of body movement.

20. The method of claim 18, wherein comparing at least one of the digital signals to the predetermined threshold comprises: the breathing rate digital signal is compared to at least one of a minimum breathing rate and a maximum breathing rate.

21. The method of claim 18, wherein comparing at least one of the digital signals to the predetermined threshold comprises: the heart rate digital signal is compared to at least one of the minimum heart rate and the maximum heart rate.

22. The method of claim 18, wherein providing patient data to a user comprises: activating an alarm when the at least one digital signal does not meet the at least one predetermined threshold.

23. The method of claim 1, further comprising:

comparing at least one of said digital signals with at least one earlier digital signal; and

identifying a trend of a patient parameter based on a comparison of the digital signal with the earlier digital signal.

24. The method of claim 23, further comprising activating an alarm when said patient parameter trend matches a predetermined negative trend.

25. The method of claim 24, wherein comparing at least one of the digital signals comprises:

comparing the at least one heart beat signal with at least one earlier heart beat signal; and

comparing the at least one respiration signal with at least one earlier respiration 6 signal;

wherein the negative trend comprises a combination of a negative heart beat trend and a negative breathing trend.

26. The method of claim 1, wherein providing patient data to a user comprises: activating an alarm based on the comparison of the digital signals.

27. The method of claim 26, wherein providing patient data to a user further comprises: providing a location of the patient on the surface.

28. The method of claim 26, wherein providing patient data to a user further comprises: providing the patient's breathing frequency.

29. The method of claim 26, wherein providing patient data to a user further comprises: providing the patient's heart rate.

30. The method of claim 1, wherein the at least one patient comprises a plurality of patients, and wherein providing patient data comprises providing data at a common 3-location.

31. The method of claim 30, wherein the plurality of patients comprises a plurality of patients in a general care area of a hospital, a long-term care facility, or a nursing home.

32. The method of claim 30, wherein the common location is selected from the group consisting of a nursing station, a display monitor, a digital pager, a wireless handheld device, a call station, and a monitoring room.

33. A method of passive physiological monitoring of a plurality of patients, the method comprising:

providing a plurality of sensor devices on a plurality of surfaces, each sensor device having at least two piezoelectric sensors;

coupling each patient with at least a portion of one of said sensor devices by having the patient lie, sit, lean, stand on or wear one of said surfaces;

detecting at least one mechanical signal with at least two of said piezoelectric sensors on each sensor device;

converting the detected mechanical signal into a digital signal;

comparing, for each patient, the digital signals corresponding to at least two of the piezoelectric sensors; and

patient data corresponding to a plurality of patients is provided to a user at a central location based on the comparison of the digital signals.

34. An apparatus for passively monitoring a patient, the apparatus comprising:

a surface for engaging the patient;

at least two piezoelectric sensors associated with said surface for detecting at least one mechanical signal from said patient;

a processor coupled to the piezoelectric sensors for converting the at least one mechanical signal to at least one digital signal and for comparing the digital signals corresponding to the at least two piezoelectric sensors to provide data about the patient;

at least one first connector for connecting the piezoelectric sensor to the processor; and

at least one second connector for connecting the processor to a device for providing the patient data to a user.

35. The apparatus of claim 34, wherein the surface comprises a flat pad.

36. The apparatus of claim 35, wherein the flat pad comprises at least one layer of resilient foam material.

37. The apparatus of claim 34, wherein the piezoelectric sensors are arranged along the surface in a pattern that facilitates monitoring at least one of patient body position, patient motion, patient breathing rate, and patient heart rate.

38. The apparatus of claim 37, wherein the pattern comprises two or more adjacent, flat piezoelectric sensors.

39. An apparatus as defined in claim 38, wherein the pattern comprises a grid pattern comprising at least two adjacent rows and at least two columns of piezoelectric sensors.

40. The apparatus of claim 34, wherein the surface is sized to be placed on at least one of a crib and a bed to monitor an infant.

41. The apparatus of claim 34, wherein the surface is sized to be placed on a bed to monitor a patient in a hospital, long-term care facility, or nursing home.

42. The apparatus of claim 34, wherein the surface is sized to be placed in a chair to monitor a patient undergoing operation under conscious sedation.

43. The apparatus of claim 34, further comprising a housing for containing at least a portion of the surface to provide a protective layer between the surface and the patient.

44. The apparatus of claim 43, wherein the housing is waterproof.

45. An apparatus as in claim 43, wherein the housing comprises at least one housing-surface connector, and wherein the surface must be connected to the housing via the housing-surface connector in order to monitor the at least one mechanical signal of the patient.

46. The apparatus according to claim 43, wherein said housing is disposable after use in monitoring a patient.

47. The apparatus of claim 34, wherein the piezoelectric sensor is selected from the group consisting of polyvinylidene fluoride membrane, polyvinylidene fluoride cable, piezoelectric ceramic disk, and piezoelectric foam.

48. The apparatus of claim 34, wherein said surface is disposed on a flat surface of a bed, and wherein at least one mechanical signal of said patient may be monitored while said patient is lying on said surface.

49. The apparatus of claim 34, wherein the at least one mechanical signal comprises at least one of a pressure signal, a thermal signal, and an acoustic signal.

50. The apparatus of claim 34, wherein the first connector includes means for detecting at least one of a type of sensor device connected to the processor and a number of times the sensor device has been used.

51. The apparatus of claim 50, wherein the first connector further comprises a means for activating the sensor device.

52. The apparatus of claim 34, wherein at least one of the first and second connectors comprises a wireless transmitter.

53. The apparatus of claim 34, wherein the processor provides the patient data by activating an alarm.

54. The apparatus of claim 53, wherein the processor activates the alarm if the comparison of the digital signals indicates that the patient is not moving on the surface, that the patient is not in contact with the surface, or that the patient is moving excessively on the surface.

55. The apparatus according to claim 53, wherein the processor activates the alarm if the patient's breathing rate is below a predetermined minimum breathing rate or above a predetermined maximum breathing rate.

56. The apparatus according to claim 53, wherein the processor activates the alarm if the patient's heart rate is below a predetermined minimum heart rate or above a predetermined maximum heart rate.

57. The apparatus of claim 53, wherein the processor further provides the patient data in the form of a patient breathing rate.

58. The apparatus of claim 53, wherein the processor further provides the patient data in the form of a patient heart rate.

59. The apparatus of claim 53, wherein the processor further provides the patient data in the form of a patient location on the surface.

60. A disposable cover for containing at least a portion of a sensor device for passively monitoring a patient, the cover comprising:

a planar surface for engaging the patient; and

at least one casing for containing at least a portion of the sensor device.

61. The disposable enclosure of claim 60, wherein the enclosure is waterproof.

62. The disposable housing of claim 60, further comprising at least one connector for removably connecting the housing to a passive physiological monitoring device, wherein connecting the housing to the device allows the device to be activated to monitor the physiology of the patient.

63. A system for passively monitoring a plurality of patients, the system comprising:

a plurality of sensor devices, each sensor device comprising: a surface for engaging the patient; and at least two piezoelectric sensors associated with said surface for detecting at least one mechanical signal from the patient;

a plurality of processors, each processor coupled to one sensor device for converting at least one mechanical signal to at least one digital signal and for comparing the digital signals corresponding to each of the at least two piezoelectric sensors to provide data about the patient; and

at least one connector is coupled to each processor for connecting each processor to a common device for providing patient data for a plurality of patients to a user.

64. The system of claim 63, wherein the surface comprises a flat pad.

65. The system of claim 64, wherein the flat pad comprises at least one layer of resilient foam material.

66. The system of claim 63, wherein the piezoelectric sensors are arranged along the surface in a pattern that facilitates monitoring at least one of patient body position, patient motion, patient breathing rate, and patient heart rate.

67. The system of claim 66, wherein the pattern comprises two or more adjacent, flat piezoelectric sensors.

68. The system of claim 67, wherein the pattern comprises a grid pattern comprising at least two adjacent rows and at least two columns of piezoelectric sensors.

69. The system of claim 63, wherein the surface is sized to be placed on at least one of a crib and a bed to monitor an infant.

70. The system of claim 63, wherein the surface is sized to be placed in a bed to monitor a patient in a hospital, a long-term care facility, or a nursing home.

71. The system of claim 63, wherein the surface is sized to be placed in a chair to monitor a patient undergoing conscious sedation.

72. The system of claim 63, further comprising a housing for containing at least a portion of the surface to provide a protective layer between the surface and the patient.

73. The system of claim 72, wherein the enclosure is waterproof.

74. The system of claim 72, wherein the housing includes at least one housing-surface connector, and wherein the surface must be connected to the housing via the housing-surface connector in order to monitor at least one mechanical signal of the patient.

75. The system of claim 72, wherein said housing is disposable after being used to monitor a patient.

76. The system of claim 63, wherein the piezoelectric sensor is selected from the group consisting of polyvinylidene fluoride films, polyvinylidene fluoride cables, piezoelectric ceramic disks, and piezoelectric foams.

77. The system of claim 63, wherein the surface is disposed on a flat surface of a bed, and wherein at least one mechanical signal of the patient may be monitored while the patient is lying on the surface.

78. The system according to claim 63, wherein the at least one mechanical signal comprises at least one of a pressure signal, a thermal signal, and an acoustic signal.

79. The system of claim 63, wherein each of the sensor devices is coupled to one of the processors by a wireless connection.

80. The system of claim 63, wherein the at least one connector connects each of the processors to: at least one of a public alarm, a public display device; at least one digital pager; at least one handheld wireless device; an Ethernet connection; an internet connection and an intranet connection.

81. The system of claim 63, wherein the plurality of processors each provide patient data by activating an alarm.

82. The system of claim 81, wherein the plurality of processors each activate the alarm if the comparison of the digital signals indicates that the patient is not moving on the surface, that the patient is not in contact with the surface, or that the patient is moving excessively on the surface.

83. The system of claim 81, wherein each of the plurality of processors activates the alarm if the patient's breathing rate is below a predetermined minimum breathing rate or above a predetermined maximum breathing rate.

84. The system according to claim 81, wherein each of the plurality of processors activates the alarm if the patient's heart rate is below a predetermined minimum heart rate or above a predetermined maximum heart rate.

85. The system of claim 81, the plurality of processors each further providing the patient data in the form of a patient breathing rate.

86. The system of claim 81, wherein each of the plurality of processors further provides the patient data in the form of a patient heart rate.

87. The system of claim 81, wherein each of the plurality of processors further provides the patient data in the form of a patient location on the surface.