Pressure ulcer condition sensing and monitoring

A medical sensor providing wireless communication of the sensing of a human body pressure condition, comprising:

• a dressing applicable to a human body at a decubitus ulcer site or a site susceptible to developing a decubitus ulcer;
• and
• a pressure responsive circuit connected to the dressing, including:
• a switch repeatably operable between a first state and a second state in response to whether pressure above a predetermined threshold is applied by at least partial weight of the human body when the dressing is applied to the human body;
• and
• resonant circuit elements connected to the switch to define on the dressing a self-contained resonant circuit.

A medical sensor responsive to an external human body pressure condition, comprising:

• a switch operable in a circuit operative state in response to pressure applied to the outside of a human body;
• resonant circuit elements connected to the switch to define a resonant circuit responsive to an electromagnetic field originating outside the sensor at least when the switch is in the circuit operative state;
• and
• means for attaching the switch and the resonant circuit elements to the outside of the human body such that the switch is exposed to an occurrence of the pressure applied to the outside of the human body.

A medical sensor responsive to a predetermined condition, comprising:

• a switch operable in a circuit operative state in response to the predetermined condition;
• resonant circuit elements connected to the switch to define a resonant circuit responsive to electromagnetic induction at least when the switch is in the circuit operative state;
• and
• means for attaching the switch and the resonant circuit elements relative to a human body such that the switch is exposed to an occurrence of the predetermined condition;
• wherein the predetermined condition is a predetermined pressure magnitude created by at least partial weight of the human body applied at a predetermined location of the human body against a support surface and further wherein the means for attaching is adapted to attach at the predetermined location of the human body such that at least the switch is between the human body and the support surface when the predetermined pressure magnitude is exceeded at the predetermined location.

A method of monitoring pressure applied to a pressure sensitive area of a human body, comprising:

• connecting a medical sensor to the pressure sensitive area of the human body;
• repeatedly operating a switch in the medical sensor between at least two states in response to repeated movement of the human body causing a pressure at the pressure sensitive area due to at least partial weight of the human body against a support surface to change repeatedly at least between less than a predetermined pressure magnitude and greater than the predetermined pressure magnitude, wherein the switch is connected in a resonant circuit in the medical sensor;
• and
• detecting a respective resonant electromagnetic wave signal generated in response to operating the switch in each of the states.

A system to monitor a pressure sensitive area of a patient positioned on a support, comprising:

• an electromagnetic wave transmitter disposed adjacent the support;
• a resonant signal detector disposed adjacent the support in operative association with the electromagnetic wave transmitter;
• a medical sensor adapted to be attached to the patient such that the medical sensor is responsive to pressure applied to the pressure sensitive area of the patient, the medical sensor including a resonant circuit operative in at least two states in response to pressure applied to the pressure sensitive area of the patient, in at least one of the states the resonant circuit causing a resonant signal to be propagated in cooperative operation with the electromagnetic wave transmitter, wherein the medical sensor is not tangibly attached to the electromagnetic wave transmitter or the resonant signal detector when the medical sensor is attached to the patient;
• and
• a controller connected to the resonant signal detector such that the controller receives a respective signal from the resonant signal detector in response to the resonant signal detector detecting a respective propagated resonant signal, wherein the controller computes an exposure time value in response to a predetermined exposure time monitoring period and a cumulative time within the exposure time monitoring period during which the controller receives signals from the resonant signal detector indicating pressure applied to the pressure sensitive area greater than a predetermined magnitude.

A system to monitor a pressure sensitive area of a patient positioned on a support, comprising:

• an electromagnetic wave transmitter disposed adjacent the support;
• a resonant signal detector disposed adjacent the support in operative association with the electromagnetic wave transmitter;
• a medical sensor adapted to be attached to the patient such that the medical sensor is responsive to pressure applied to the pressure sensitive area of the patient, the medical sensor including a resonant circuit operative in at least two states in response to pressure applied to the pressure sensitive area of the patient, in at least one of the states the resonant circuit causing a resonant signal to be propagated in cooperative operation with the electromagnetic wave transmitter, wherein the medical sensor is not tangibly attached to the electromagnetic wave transmitter or the resonant signal detector when the medical sensor is attached to the patient;
• and
• a controller connected to the resonant signal detector such that the controller receives a respective signal from the resonant signal detector in response to the resonant signal detector detecting a respective propagated resonant signal, wherein the controller is programmed to compute a shift frequency value in response to a predetermined monitoring period and the number of transitions relative to receiving signals from the resonant signal detector during the monitoring period.

A system to monitor a plurality of external pressure sensitive areas of a patient lying on a bed, comprising:

• a variable frequency electromagnetic wave transmitter disposed to one side of the bed;
• a resonant signal detector disposed to another side of the bed in operative association with the electromagnetic wave transmitter such that an electromagnetic field generated by the transmitter exists between the transmitter and the detector;
• a plurality of medical sensors, wherein each of the medical sensors is adapted to attach to the patient at a respective external pressure sensitive area susceptible to decubitus ulceration, each of the medical sensors includes a respective resonant circuit operative in at least two states in response to pressure applied to the respective medical sensor, in at least one of the states the respective resonant circuit causing a respective resonant signal to be propagated in cooperative operation with the electromagnetic wave transmitter and the electromagnetic field generated by the transmitter;
• and
• a controller connected to the resonant signal detector such that the controller receives a respective signal from the resonant signal detector in response to the resonant signal detector detecting each propagated resonant signal.

A system to monitor a plurality of pressure sensitive areas of a patient lying on a bed, comprising:

• a variable frequency electromagnetic wave transmitter disposed to one side of the bed;
• a resonant signal detector disposed to another side of the bed in operative association with the electromagnetic wave transmitter such that an electromagnetic field generated by the transmitter exists between the transmitter and the detector;
• a plurality of medical sensors, wherein each of the medical sensors is adapted to attach to the patient at a respective pressure sensitive area susceptible to decubitus ulceration, each of the medical sensors includes a respective resonant circuit operative in at least two states in response to pressure applied to the respective medical sensor, in at least one of the states the respective resonant circuit causing a respective resonant signal to be propagated in cooperative operation with the electromagnetic wave transmitter and the electromagnetic field generated by the transmitter;
• and
• a controller connected to the resonant signal detector such that the controller receives a respective signal from the resonant signal detector in response to the resonant signal detector detecting each propagated resonant signal;
• wherein the controller is programmed to compute an exposure time value relative to each of the medical sensors, wherein the exposure time value for each medical sensor is computed in response to a predetermined exposure time monitoring period and a cumulative time within the exposure time monitoring period during which the controller receives signals from the resonant signal detector indicating pressure applied to the respective medical sensor greater than a predetermined magnitude.

A system to monitor a plurality of pressure sensitive areas of a patient lying on a bed, comprising:

• a variable frequency electromagnetic wave transmitter disposed to one side of the bed;
• a resonant signal detector disposed to another side of the bed in operative association with the electromagnetic wave transmitter such that an electromagnetic field generated by the transmitter exists between the transmitter and the detector;
• a plurality of medical sensors, wherein each of the medical sensors is adapted to attach to the patient at a respective pressure sensitive area susceptible to decubitus ulceration, each of the medical sensors includes a respective resonant circuit operative in at least two states in response to pressure applied to the respective medical sensor, in at least one of the states the respective resonant circuit causing a respective resonant signal to be propagated in cooperative operation with the electromagnetic wave transmitter and the electromagnetic field generated by the transmitter;
• and
• a controller connected to the resonant signal detector such that the controller receives a respective signal from the resonant signal detector in response to the resonant signal detector detecting each propagated resonant signal;
• wherein the controller is programmed to compute, relative to each of the medical sensors, a shift frequency value in response to a predetermined monitoring period and the number of transitions in signals received from the resonant signal detector during the monitoring period for the respective sensor.

A method of monitoring for a pressure sensor adapted to be attached externally to a patient, comprising:

• transmitting, across a region in which a patient is disposed, a driving signal having at least one frequency to which a pressure sensor adapted to be attached externally to the patient is responsive if the pressure sensor is attached to the patient and operational;
• detecting whether a first response signal is emitted from the sensor in the region in response to the driving signal, the first response signal indicating the presence of the operational sensor in the region;
• detecting whether a second response signal is emitted from the sensor in the region in response to the driving signal, the second response signal indicating an external pressure condition related to the patient;
• and
• repeating the transmitting and detecting steps for respective selected frequencies of the driving signal and respective responsive frequencies for the first and second response signals for a plurality of sensors adapted to be attached to the patient such that each sensor is uniquely identified.

A method of monitoring for a pressure sensor adapted to be attached externally to a patient, comprising:

• transmitting, across a region in which a patient is disposed, a driving signal having at least one frequency to which a pressure sensor adapted to be attached externally to the patient is responsive if the pressure sensor is attached to the patient and operational;
• detecting whether a first response signal is emitted from the sensor in the region in response to the driving signal, the first response signal indicating the presence of the operational sensor in the region;
• and
• detecting whether a second response signal is emitted from the sensor in the region in response to the driving signal, the second response signal indicating an external pressure condition related to the patient;
• wherein the driving signal is transmitted from different locations relative to the region and wherein detecting occurs from different locations relative to the region such that the first and second response signals are within detection range of at least one of the locations.

A method of monitoring for a pressure sensor adapted to be attached externally to a patient, comprising:

• transmitting, across a region in which a patient is disposed, a driving signal having at least one frequency to which a pressure sensor adapted to be attached externally to the patient is responsive if the pressure sensor is attached to the patient and operational;
• detecting whether a first response signal is emitted from the sensor in the region in response to the driving signal, the first response signal indicating the presence of the operational sensor in the region;
• and
• detecting whether a second response signal is emitted from the sensor in the region in response to the driving signal, the second response signal indicating an external pressure condition related to the patient;
• wherein transmitting the driving signal includes sequentially providing the driving signal from different locations relative to the region and wherein detecting occurs from different locations relative to the region such that the first and second response signals are within detection range of at least one of the locations.

A method of monitoring for a sensor adapted to be attached to a patient, comprising:

• transmitting, across a region in which a patient is disposed, a first driving signal having a first frequency to which a sensor adapted to be attached to the patient is responsive if the sensor is attached to the patient and if the sensor is in at least a first operating state;
• detecting whether a first response signal is emitted from the sensor in the region in response to the first driving signal;
• in response to detecting the first response signal, transmitting across the region a second driving signal having a second frequency to which the sensor is responsive in at least a second operating state;
• and
• detecting whether a second response signal is emitted from the sensor in response to the second driving signal, the second response signal indicating a condition related to the patient.

A method of monitoring a pressure sensitive area of a patient on a support, comprising:

• communicating signals indicating (1) that pressure above a predetermined magnitude has been exerted against the pressure sensitive area and (2) changes between pressure above the predetermined magnitude and pressure below the predetermined magnitude;
• computing a shift frequency value in response to a predetermined shift frequency monitoring period and the number of changes between pressure above the predetermined magnitude and pressure below the predetermined magnitude occurring during the predetermined shift frequency monitoring period as indicated by the communicated signals;
• and
• moving the patient in response to the computed shift frequency value.

A computer-implemented pressure ulcer management method, comprising:

• maintaining in a computer a database containing a respective ulceration history for each of a plurality of patients, each ulceration history including data identifying information relevant to the respective patient's susceptibility to ulcer formation;
• monitoring the patients, including for each patient sensing pressure application to at least one location on the respective patient at risk to ulcer formation and communicating additional data to the computer in response to sensed pressure application;
• storing in the computer the additional data with the data in the database;
• and
• managing the care of each patient in response to that patient's respective ulceration history and the respective stored additional data.

A computer-implemented pressure ulcer management method, comprising:

• maintaining in a computer a database containing a respective ulceration history for each of a plurality of patients, each ulceration history including historical data identifying previous ulcers, the number of previous ulcers occurring at the same location of the respective patient, when each previous ulcer was detected at the respective location, and when each previous ulcer was healed;
• monitoring the patients, including for each patient sensing pressure application to each previous ulcer location identified by the data in the database and communicating additional data to the computer in response to sensed pressure application;
• and
• storing in the computer the additional data with the data in the database.

A computer-implemented pressure ulcer management method, comprising:

• maintaining in a computer a database containing a respective predetermined ulceration event for each of a plurality of patients;
• monitoring the patients, including for each patient sensing pressure application to at least one location of the respective patient susceptible to ulceration and communicating data to the computer defining shifts of the respective patient between pressure-on and pressure-off events relative to the at least one location in response to sensed pressure application;
• and
• correlating in the computer the communicated data with the respective predetermined ulceration event for each of the patients.