Systems and methods for normalization of chemical sensor data based on fluid state changes

• US 10,716,500 B2
• Filed: 06/22/2016
• Issued: 07/21/2020
• Est. Priority Date: 06/29/2015
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Stahmann, Jeffrey E.
• Primary Examiner(s): Winakur, Eric F
• Assistant Examiner(s): Mustansir, Abid A
• Application Number:
  US15/189,400
• Publication Number:
  US 20160374597A1
• Time in Patent Office: 1,490 Days
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• 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 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6861 Capsules, e.g. for swallowing or implanting
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 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: A61N 1/36 for stimulation
• CPC Class Codes: A61N 1/36557 controlled by chemical substances in blood
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient

Abstract

Embodiments herein include implantable medical systems, devices and methods including chemical sensors. In an embodiment, an implantable medical device system includes a chemical sensor; a fluid state sensor such as a posture sensor; an activity sensor; and/or a respiration sensor. The implantable medical device system can further include normalization circuitry receiving data from the chemical sensor and the fluid state sensor and normalizing the chemical sensor data based on data from the fluid state sensor. In an embodiment, a method of operating an implantable medical device system is included. The method can include measuring the amount of a chemical analyte using a chemical sensor, measuring the fluid status in a patient using a fluid state sensor, and normalizing the measured amount of the chemical analyte as indicated by the chemical sensor using normalization circuitry based on data from the fluid state sensor. Other embodiments are also included herein.

Claims

1. An implantable medical device system comprising:

a chemical sensor configured to generate chemical sensor data;

a fluid state sensor, the fluid state sensor comprising a posture sensor configured to generate fluid state sensor data to differentiate between patient postures, the fluid state sensor data corresponding to patient postures comprising at least an upright posture and a recumbent posture; and

normalization circuitry configured to receive the chemical sensor data and the fluid state sensor data and normalize the chemical sensor data based on the patient postures comprising at least an upright posture and a recumbent posture corresponding to the fluid state sensor data; and

wherein the normalization circuitry is further configured to categorize the chemical sensor data based on the patient postures comprising at least an upright posture and a recumbent posture corresponding to the fluid state sensor data.

2. The implantable medical device system of claim 1, the normalization circuitry discarding chemical sensor data, ignoring chemical sensor data, or suspending chemical sensor data collection when the fluid state sensor data indicates a fluid state exceeding a threshold value.

3. The implantable medical device system of claim 1, the normalization circuitry labeling data coming from the chemical sensor based on the patient postures corresponding to the fluid state sensor data.

4. The implantable medical device system of claim 1, wherein the categorization of chemical sensor data based on the patient postures comprising at least an upright posture and a recumbent posture corresponding to the fluid state sensor data further comprises categorizing the chemical sensor data into one or more categories comprising a fully recumbent posture or a partially recumbent posture.

5. The implantable medical device system of claim 4, the normalization circuitry adjusting alert and/or therapy thresholds according to the category.

6. The implantable medical device system of claim 4, the normalization circuitry adjusting the chemical sensor data according to the category.

7. The implantable medical device system of claim 1, wherein the normalization circuitry matches fluid state sensor data with chemical sensor data that is offset in time from one another.

8. The implantable medical device system of claim 1, wherein the normalization circuitry uses fluid state sensor data from an earlier time to process chemical sensor data from a later time.

9. The implantable medical device system of claim 1, the normalization circuitry matching a measured fluid state as determined by the fluid state sensor data to a template for that fluid state.

10. The implantable medical device system of claim 9, the normalization circuitry further adjusting the chemical sensor values according to the template.

11. The implantable medical device system of claim 1, the normalization circuitry calculating a weighted average for the chemical sensor data with the weight based on the fluid state sensor data.

12. The implantable medical device system of claim 1, the chemical sensor data comprising native values for amounts of a measured physiological analyte;

the normalization circuitry generating a normalized value by

increasing the native value when a fluid state sensor measured value indicates that the measured physiological analyte has been decreased; and

decreasing the native value when a fluid state sensor measured value indicates that the measured physiological analyte has been increased.

13. The implantable medical device system of claim 1, further comprising therapy control circuitry controlling parameters of a therapy delivery to a patient;

the therapy control circuitry to omit changes in physiological analyte concentrations from consideration when the normalization circuitry indicates that current chemical sensor data is unreliable.

14. The implantable medical device system of claim 1, further comprising recorder circuitry to record the data produced by the chemical sensor and/or the fluid state sensor and time stamps regarding the same.

15. The implantable medical device system of claim 1, the normalization circuitry producing normalized chemical sensor data;

the system further comprising recording circuitry to record the normalized chemical sensor data and time stamps regarding the same.

18. The implantable medical device system of claim 1, wherein the posture sensor comprises an accelerometer configured to detect a posture that is vertically or horizontally oriented;

or an impedance sensor configured to measure a trans-thoracic or vessel impedance to determine the patient'"'"'s posture.

19. The implantable medical device system of claim 1, wherein the normalization circuitry is further configured to shift one or more threshold values or one or more ranges, for issuing an alert, initiating a therapy, or controlling a therapy based on the fluid state data.

16. An implantable medical device system comprising:

a chemical sensor;

a fluid state sensor comprising

a posture sensor configured to generate fluid state sensor data used to differentiate between patient postures, the fluid state sensor data corresponding to patient postures comprising at least an upright posture and a recumbent posture; and

an external interface device configured to communicate with the implantable medical device;

the external interface device including a processor configured to receive data from the chemical sensor and the fluid state sensor and normalize the chemical sensor data based on the patient postures comprising at least an upright posture and a recumbent posture corresponding to the fluid state sensor data; and

wherein the processor is further configured to categorize the chemical sensor data based on the patient postures comprising at least an upright posture and a recumbent posture corresponding to the fluid state sensor data.

17. A method of operating an implantable medical device system comprising:

measuring the amount of a chemical analyte using a chemical sensor;

normalizing the measured amount of the chemical analyte as indicated by the chemical sensor using normalization circuitry based on the patient postures comprising at least an upright posture and a recumbent posture corresponding to the posture sensor data; and

categorizing the chemical sensor data based on the patient postures comprising at least an upright posture and a recumbent posture corresponding posture sensor data.