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US-12622637-B2 - Systems and methods for prevention of pressure ulcers

US12622637B2US 12622637 B2US12622637 B2US 12622637B2US-12622637-B2

Abstract

Systems, devices, and methods of the present application relate to the diagnostic measurement of condition for pressure ulcers. Preferred embodiments utilize pressure measurements at body locations to determine a diagnostic pressure ulcer value. A pressure sensor device generates patient pressure data that is processed by a data processor which utilizes a diagnostic function to determine the diagnostic value that indicates whether corrective action is needed to prevent pressure ulcer formation. One or more sensor devices can be attached to a patient to measure to transmit data for further processing.

Inventors

  • Raymond Dunn
  • John McNeill
  • Yitzhak Mendelson
  • Hamza Abujrida

Assignees

  • UNIVERSITY OF MASSACHUSETTS
  • WORCESTER POLYTECHNIC INSTITUTE

Dates

Publication Date
20260512
Application Date
20210607

Claims (20)

  1. 1 . A method of determining a pressure ulcer condition of a patient comprising: entering patient data with a pressure ulcer monitoring system, the system configured to perform computational operations on measured pressure sensor data at a selected tissue surface location on the patient, the computational operations including computing a diagnostic value of a pressure ulcer diagnostic function of the patient using the patient data and the measured pressure sensor data at the selected tissue surface location; detecting pressure data with a sensor patch device having a pressure sensor with a pressure sensitive area at the selected tissue surface location on the patient wherein the sensor patch device is powered by a battery and includes a control circuit and a wireless transmitter that transmits measured pressure sensor data above a threshold value to an external data processing device, the pressure sensor comprising an array of pressure sensor elements defining the pressure sensitive area that is attached to skin of the patient at the selected tissue surface location with an adhesive; and automatically computing the diagnostic value with the external data processing device using an accumulated value of the measured pressure sensor data at each pressure sensor element of the array of pressure sensor elements sensing pressure above the threshold value during a controlled time interval and detected with the array of pressure sensor elements and processed using the pressure ulcer diagnostic function that includes the selected tissue surface location on the patient and a plurality of patient characteristics including the weight of the patient.
  2. 2 . The method of claim 1 wherein the step of detecting pressure data with the sensor patch device further comprises attaching a first conformable patch at the tissue surface a location on the patient, the sensor patch device including at least one of a temperature sensor, a humidity sensor and a bioimpedance sensor and a flexible circuit device connected to the sensor patch device, the flexible circuit device including the wireless transmitter.
  3. 3 . The method of claim 1 , wherein the computational operations include processing pressure ulcer data sensed using a pressure sensor patch on a heel of a foot of the patient with a machine learning module that comprises at least one of a support vector machine, a neural network or a Bayesian network.
  4. 4 . The method of claim 1 wherein the computational operations include processing pressure ulcer data with a machine learning module that comprises one or more decision trees based on an age of the patient, a medication of the patient, the tissue surface location of the pressure sensor on the patient, and a blood pressure of the patient.
  5. 5 . The method of claim 1 , further comprising sensing one or more of a temperature, a humidity, or an orientation at the tissue surface location with the sensor patch device.
  6. 6 . The method of claim 3 , wherein the learning module operates a bagged tree program or a random forest program or wherein the learning module comprises a boosting algorithm, or wherein the learning module processes a plurality of weak classifiers.
  7. 7 . The method of claim 1 , further comprising processing at least one of the patient data and the pressure data with a machine learning module having one or more analytic features to compute one or more metrics wherein the learning module segments the sensed data, selects one or more features, and ranks a metric value for the one or more features.
  8. 8 . The method of claim 1 further comprising controlling transmission of pressure sensor data above the threshold for each pressure sensor element with the control circuit mounted on a circuit board within the sensor patch device.
  9. 9 . The method of claim 1 wherein detecting pressure data comprises measuring pressure with each pressure sensor element of the array of pressure sensor elements, each pressure sensor element comprising a resistive pressure sensing element.
  10. 10 . The method of claim 1 wherein detecting pressure data comprises measuring pressure with each pressure sensor element of the array of pressure sensor elements, each pressure sensor element comprising a capacitive pressure sensing element.
  11. 11 . The method of claim 1 wherein the detecting step further comprises recording a time of each pressure measurement with the array of pressure sensor elements.
  12. 12 . The method of claim 1 further comprising recording a location of the sensor patch device on the patient during the step of detecting pressure data.
  13. 13 . The method of claim 1 further comprising entering the patient data using a data processor that wirelessly communicates with the sensor patch device.
  14. 14 . The method of claim 1 further comprising time stamping the measured pressure sensor data for wireless transmission.
  15. 15 . The method of claim 14 further comprising wirelessly transmitting a location data with the time stamped measured pressure sensor data.
  16. 16 . The method of claim 14 further comprising wirelessly transmitting temperature data with the time stamped measured pressure sensor data.
  17. 17 . The method of claim 1 wherein the array of pressure sensing elements comprises a two dimensional array.
  18. 18 . The method of claim 1 wherein the sensor patch device has a thickness of less than 4 mm and includes seal and an adhesive layer to attach to skin of the patient.
  19. 19 . The method of claim 1 wherein the sensor patch device further comprises a power management circuit connected to the battery.
  20. 20 . The method of claim 13 wherein the value of the pressure ulcer diagnostic function can exceed a threshold value whereby the data processor transmits a signal to communicate a change of patient condition to a user.

Description

RELATED APPLICATION This application is a continuation of International Patent Application PCT/US2019/065074, filed Dec. 6, 2019, which is a continuation-in-part of U.S. patent application Ser. No. 16/212,576, filed Dec. 6, 2018, which is a continuation-in-part of International Patent Application PCT/US2017/036208, filed Jun. 6, 2017, which claims priority to U.S. Provisional Application 62/346,151, filed Jun. 6, 2016, the entire contents of each of these applications being incorporated herein by reference. BACKGROUND OF THE INVENTION A pressure ulcer, commonly referred to as a bed sore, is defined as a breakdown of the skin due to a lack of blood flow and often results in an increase in pressure on boney prominences. The most common locations of pressure ulcers are on the back of the heels, the backbone, and the shoulder blades although pressure ulcers can form in nearly any location on the body. There are millions of cases of pressure ulcers in the world each year, and 2.4 million cases were recorded in the United States alone in 2007. There are substantial costs for the treatment of a single pressure ulcer, and, in some cases, insurers have indicated that they will no longer reimburse hospitals for the treatment of pressure ulcers as they are classified as a preventable problem. Other than periodic patient movement, there are currently no methods in general use for preventing pressure ulcers. The current standard of care has clinicians taking preventative measures to help decrease the likelihood of forming pressure ulcers based on clinical practice guidelines. Existing approaches have utilized sensors integrated into patient supports such as tables or beds. However, when the patient is turned, the measurement is disrupted so that the cumulative impact of pressure over time is not considered. When these measures fail, ulcers are diagnosed and treated based on a scale of severity. All too often, the preventative measures are not effective enough to prevent pressure ulcers at an early stage thereby creating a need for costly and painful treatment of the ulcers. Further improvements in the diagnostic assessment of pressure ulcer formation are needed. SUMMARY OF THE INVENTION The present invention relates to devices and methods for detecting the formation of pressure ulcers. Preferred embodiments utilized measured sensor data that is processed to determine a diagnostic value indicative of pressure ulcer formation. A sensor device in accordance with such embodiments can include at least one pressure sensor and a processing device that receives pressure data and processes this data using a diagnostic function to determine whether the patient or their caregiver should take action to avoid injury. As the conditions under which pressure ulcers will occur in a given patient depend on the specific condition of that patient, simply measuring the pressure applied at any instant to the skin of a patient does not provide meaningful information that is useful to the patient or caregiver. A particular pressure measurement at a particular time, for example, may indicate that no action is needed or that immediate corrective action is necessary both of which can be false depending on the circumstances. In conventional systems, time domain based measurements to determine the accumulated effects at a selected location on a patient's body are not available. Preferred embodiments employ a number of patient specific attributes that are used to determine a diagnostic function for each individual patient. Patient attributes can include one or more body locations at which pressure is being measured, the weight or body mass of the patient as well as the age, medical condition, medical history, mobility, nutrition, blood oxygenation, blood pressure, temperature and other factors impacting diagnostic assessment. The diagnostic function provides a quantitative analysis to indicate to the user that a patient is at low or high risk of ulcer formation, for example. The diagnostic function can be the sum of weighted parameters, each parameter having a coefficient to define the weight given to the respective parameter, for example, or another analytic expression can be used that enables accurate computation of a quantitative diagnostic value over time. A location on the heel of a patient having peripheral vascular disease, for example, will have a substantially lower threshold than a location on a shoulder of a healthy child. In some embodiments, the diagnostic function can include a machine learning module that can comprise a Bayesian statistical data integration algorithm, for example. A preferred embodiment can employ a conformable sensor patch that can be fixedly attached to one or more body locations of a particular patient. The device can include a wireless transmitter, a data processor, a power source such as a battery, and one or more sensor elements such as a pressure sensor or array of sensors, a bioimpedance sensor, a temperature