Calibrated Systems, Devices and Methods for Preventing, Detecting, and Treating Pressure-Induced Ischemia, Pressure Ulcers, and Other Conditions

• US 20160296159A1
• Filed: 06/15/2016
• Published: 10/13/2016
• Est. Priority Date: 04/22/2010
• Status: Active Grant

• Current Assignee: Leaf Healthcare, Inc. (Smith & Nephew PLC)
• Original Assignee: Leaf Healthcare, Inc. (Smith & Nephew PLC)
• Inventors: LARSON, Barrett J., SHEN, Daniel Z., WECKWERTH, Mark V., HAMMOND, Charles Matthew Peterson
• Granted Patent: US 10,588,565 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A41B 9/00 Undergarments corsets A41C1/00; brassières A41C3/00
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 2562/0214 Capacitive electrodes
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 2562/0223 Magnetic field sensors
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/0261 Strain gauges
• CPC Class Codes: A61B 2562/029 Humidity sensors
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/0531 Measuring skin impedance
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1113 : Local tracking of patients, e.g. in a hospital or private home
• CPC Class Codes: A61B 5/1114 : Tracking parts of the body
• CPC Class Codes: A61B 5/1115 : Monitoring leaving of a patient support, e.g. a bed or a wheelchair
• CPC Class Codes: A61B 5/1116 : Determining posture transitions
• CPC Class Codes: A61B 5/1118 : Determining activity level
• CPC Class Codes: A61B 5/1121 : Determining geometric values, e.g. centre of rotation or angular range of movement
• CPC Class Codes: A61B 5/113 : occurring during breathing
• CPC Class Codes: A61B 5/14542 : for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14551 : for measuring blood gases
• CPC Class Codes: A61B 5/363 : Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/447 : specially adapted for aiding the prevention of ulcer or pressure sore development, i.e. before the ulcer or sore has developed
• CPC Class Codes: A61B 5/4833 : Assessment of subject's compliance to treatment
• CPC Class Codes: A61B 5/4866 : Evaluating metabolism A61B5/083 takes precedence
• CPC Class Codes: A61B 5/4884 : inducing physiological or psychological stress, e.g. applications for stress testing
• CPC Class Codes: A61B 5/6801 : specially adapted to be attached to or worn on the body surface
• CPC Class Codes: A61B 5/6804 : Garments; Clothes
• CPC Class Codes: A61B 5/6823 : Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/6843 : Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/6891 : Furniture
• CPC Class Codes: A61B 5/6892 : Mats
• CPC Class Codes: A61B 5/721 : using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7246 : using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/7275 : Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7282 : Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61B 5/746 : Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 7/00 : Instruments for auscultation
• CPC Class Codes: A61G 2203/42 : for inclination
• CPC Class Codes: A61G 2203/46 : for temperature
• CPC Class Codes: A61G 7/057 : Arrangements for preventing bed-sores or for supporting patients with burns, e.g. mattresses specially adapted therefor ventilation openings in mattresses A47C21/042; pneumatic or hydraulic mattresses A47C27/08
• CPC Class Codes: A61G 7/05769 : with inflatable chambers
• CPC Class Codes: A61G 7/05776 : with at least two groups of alternately inflated chambers
• CPC Class Codes: G01P 15/18 : in two or more dimensions
• CPC Class Codes: G01P 21/00 : Testing or calibrating of apparatus or devices covered by the preceding groups
• CPC Class Codes: G16H 20/00 : ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance
• CPC Class Codes: G16H 20/30 : relating to physical therapies or activities, e.g. physiotherapy, acupressure or exercising
• CPC Class Codes: G16H 20/40 : relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
• CPC Class Codes: G16H 40/63 : for local operation
• CPC Class Codes: G16H 40/67 : for remote operation
• CPC Class Codes: G16H 50/20 : for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/70 : for mining of medical data, e.g. analysing previous cases of other patients
• CPC Class Codes: G16H 80/00 : ICT specially adapted for facilitating communication between medical practitioners or patients, e.g. for collaborative diagnosis, therapy or health monitoring

Abstract

A system for monitoring medical conditions including pressure ulcers, pressure-induced ischemia and related medical conditions comprises at least one sensor adapted to detect one or more patient characteristic including at least position, orientation, temperature, acceleration, moisture, resistance, stress, heart rate, respiration rate, and blood oxygenation, a host for processing the data received from the sensors together with historical patient data to develop an assessment of patient condition and suggested course of treatment. In some embodiments, the system can further include a support surface having one or more sensors incorporated therein either in addition to sensors affixed to the patient or as an alternative thereof. The sensor can include bi-axial or tri-axial accelerometers, as well as resistive, inductive, capactive, magnetic and other sensing devices, depending on whether the sensor is located on the patient or the support surface, and for what purpose. Compensation for errors introduced because of chest angle or slope can be automatically performed.

Claims

1. A method for calibrating a sensor, wearable by a patient for monitoring patient movement and position, outputting acceleration data comprising

providing to a processor a correction factor to adjust for an angle of the sensor relative to a rotational axis of a patient,

providing to a processor data representative of acceleration measured by the sensor,

applying, in the processor, the correction factor to the data representative of sensor acceleration in a rotation matrix,

outputting corrected acceleration data representative of patient position with respect to the rotational axis of the patient, and

determining in a processor orientation of the patient using the corrected acceleration data.

2. The method of claim 1 wherein the rotational axis is a longitudinal axis and the angle of the sensor relative to the rotational axis is pitch.

3. The method of claim 1 wherein the rotational axis is a lateral axis and the angle of the sensor relative to the lateral axis is roll.

4. The method of claim 2 wherein the acceleration data represents acceleration along three axes.

5. The method of claim 1 wherein the correction factor is based on patient-specific data.

6. The method of claim 5 wherein the patient-specific data comprises chest angle relative to the patient'"'"'s longitudinal axis of rotation.

7. The method of claim 5 wherein the patient-specific data comprises chest angle relative to the patient'"'"'s lateral axis of rotation.

8. The method of claim 1 wherein the correction factor is predetermined.

9. The method of claim 8 where the correction factor is predetermined based on a range of known patient measurements.

10. The method of claim 2 wherein the rotation matrix is applied along the Y axis.

11. The method of claim 3 wherein the rotation matrix is applied along the X axis.

12. A method for calibrating a sensor, wearable by a patient for

monitoring patient movement and position, outputting acceleration data comprising

providing to a processor at least one correction factor to adjust for pitch and roll angles of the sensor relative to longitudinal and rotational axes of a patient,

providing to a processor data representative of multi-axis acceleration measured by the sensor,

applying, in the processor, the at least one correction factor to the data representative of sensor acceleration in a rotation matrix applied along a first axis to correct for pitch angle and in a rotation matrix along a second axis to correct for roll angle,

outputting corrected acceleration data representative of patient position with respect to rotational axes of the patient, and

determining in a processor orientation of the patient using the corrected acceleration data.

13. The method of claim 12 wherein the at least one correction factor is based on patient-specific data.

14. The method of claim 12 wherein the at least one correction factor is predetermined.

15. A method for calibrating the acceleration data output by a sensor that is wearable by a patient for monitoring patient movement and position comprising:

providing to a processor a predetermined correction factor as an offset for an angle of the sensor relative to the rotational axis of a patient, providing to a processor data representative of acceleration measured by the sensor, applying, in the processor, the correction factor to the data representative of sensor acceleration in a rotation matrix, outputting corrected acceleration data representative of patient position with respect to the rotational axis of the patient, and determining in a processor orientation of the patient using the corrected acceleration data.