MEASUREMENT OF PATIENT PHYSIOLOGICAL PARAMETERS

• US 20090198302A1
• Filed: 12/29/2008
• Published: 08/06/2009
• Est. Priority Date: 12/28/2007
• Status: Active Grant

• Current Assignee: CVRx, Inc.
• Original Assignee: CVRx, Inc.
• Inventors: Yared, Nadim, Check, Steve, Lovett, Eric, Stroebel, John Charles, Anderson, Russell Eugene, Kieval, Robert S.
• Granted Patent: US 8,116,873 B2
• Time in Patent Office: Days
• US Class Current: 607/44
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• 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 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/6862 Stents
• CPC Class Codes: A61B 5/6876 Blood vessel
• CPC Class Codes: A61N 1/36062 Spinal stimulation
• CPC Class Codes: A61N 1/36117 for treating hypertension
• CPC Class Codes: A61N 1/36139 with automatic adjustment

Abstract

A method of determining one or more physiological parameter of a patient by providing a plurality of implantable electrodes proximate a blood vessel of the patient, applying a measurement signal through the plurality of electrodes, the measurement signal having a known parameter, obtaining a resultant signal through the plurality of electrodes, the resultant signal having a resultant parameter, calculating vascular impedance based on the measurement signal and the resultant signal, and calculating a physiological parameter based on the vascular impedance. In some embodiments, the physiological parameter is utilized to modify a therapy signal controlling therapy delivered to the patient.

Claims

1. A method of determining a physiological parameter of a patient, comprising:

implanting a plurality of electrodes proximate a blood vessel of the patient;

applying a measurement signal through the plurality of electrodes, the measurement signal having a known parameter;

obtaining a resultant signal through the plurality of electrodes, the resultant signal having a resultant parameter;

calculating vascular impedance based on the measurement signal and the resultant signal; and

calculating a physiological parameter based on the vascular impedance.

2. The method of claim 1, wherein implanting a plurality of electrodes comprises implanting the electrodes intravascularly.

3. The method of claim 1, wherein implanting a plurality of electrodes comprises implanting the electrodes extravascularly.

4. The method of claim 1, wherein calculating a physiological parameter comprises calculating a parameter selected from the group consisting of blood pressure, heart rate, respiration, activity, posture, and sleep state.

5. The method of claim 1, further comprising:

providing a second plurality of electrodes, wherein the second plurality of electrodes are configured to obtain a resultant signal from the measurement signal applied to the first plurality of electrodes.

6. The method of claim 1, wherein positioning a plurality of electrodes comprises positioning the electrodes apart from one another along a longitudinal axis of the blood vessel.

7. The method of claim 1, wherein positioning a plurality of electrodes comprises positioning the electrodes at different locations about a circumference of the blood vessel.

8. The method of claim 1, further comprising providing a controller configured to apply the measurement signal and calculate vascular impedance and a physiological parameter.

9. A system, comprising:

at least one pair of measurement electrodes adapted to be implanted proximate a blood vessel of a patient;

a controller communicably coupled to the electrodes, the controller configured to calculate the impedance of the blood vessel based on a measured signal from the electrodes, and determine a physiological parameter of a patient based on the calculated impedance.

10. The system of claim 9, further comprising a baroreflex modulation device.

11. The system of claim 10, wherein the measurement electrodes are integrated with the baroreflex modulation device.

12. The system of claim 9, wherein the controller is configured to calculate impedance of the blood vessel by applying a measurement signal having a known parameter through the electrodes and receive a resultant signal having a resultant parameter through the electrodes.

13. The system of claim 12, further comprising a second pair of electrodes adapted to be implanted proximate the blood vessel, wherein one pair of electrodes is configured to transmit the measurement signal, and one pair of electrodes is configured to receive the resultant signal.

14. An implantable baroreflex therapy system for providing real-time feedback of physiological parameters comprising:

an implantable baroreflex modulation device including one or more therapy electrodes positioned proximate a blood vessel; and

a control system operably coupled to the baroreflex modulation device, the control system configured to transmit a therapy signal having a known parameter to the baroreflex modulation device,

wherein the one or more therapy electrodes are configured to monitor a resultant signal indicative of a parameter that correlates to the known parameter of the therapy signal, the control system being configured to calculate the impedance of the blood vessel based on the known parameter and the resultant parameter, determine one or more patient physiological parameters based on the calculated impedance, and modify the therapy signal based on the one or more patient physiological parameters.

15. The implantable baroreflex therapy system of claim 14, further comprising a plurality of measurement electrodes operably coupled to the baroreflex modulation device and the control system, the measurement electrodes configured to monitor the resultant signal.

16. The implantable baroreflex therapy system of claim 15, wherein the plurality of measurement electrodes are separate from, but proximate to the baroreflex modulation device.

17. The implantable baroreflex therapy system of claim 14, wherein the known parameter of the therapy signal is a constant current and the resultant parameter is voltage.

18. The implantable baroreflex therapy system of claim 14, wherein the known parameter of the therapy signal is a constant voltage and the resultant parameter is current.

19. The implantable baroreflex therapy system of claim 14, wherein the baroreflex modulation device includes two electrodes configured to be oriented about 180 degrees apart from each other along the longitudinal axis of a blood vessel in which the baroreflex modulation device is implanted.

20. A method of providing therapy having real-time feedback, comprising:

implanting a baroreflex modulation device including one or more therapy electrodes on or about a blood vessel;

implanting one or more measurement electrodes;

transmitting a therapy signal from a control system to the baroreflex modulation device, the therapy signal having at least one known parameter;

monitoring a resultant signal with one or more measurement electrodes, the resultant signal having a resultant parameter;

calculating the impedance of the blood vessel based on the known parameter and the resultant parameter;

determining one or more physiological parameters based on the impedance of the blood vessel; and

adjusting the therapy signal based on the one or more physiological parameters.

21. The method of claim 20, wherein the one or more measurement electrodes are integrated with the therapy device.

22. The method of claim 20, wherein the one or more therapy electrodes comprise the one or more measurement electrodes, and the therapy electrodes are configured to deliver a therapy and monitor the resultant signal.

23. The method of claim 20, wherein the physiological parameter is selected from the group consisting of blood pressure, heart rate, respiration, activity, posture, and sleep state.

24. A method, comprising:

providing a baroreflex modulation device including one or more electrodes;

providing a control system operably coupled to the baroreflex modulation device; and

providing instructions recorded on a tangible medium on how to provide real-time feedback of a physiological parameter of a patient undergoing baroreflex therapy, the instructions including;

implanting the baroreflex modulation device on or about a blood vessel;

delivering a therapy signal having a known parameter to the one or more electrodes of the baroreflex modulation device;

monitoring with the measurement electrodes a resultant signal having a resultant parameter as the therapy signal is being delivered;

calculating with the control system an impedance of the blood vessel based on the known parameter and the resultant parameter;

determining one or more patient parameters based on the calculated impedance;

and modifying the therapy signal based on the one or more patient parameters.

25. A kit for a baroreflex therapy system, comprising:

a baroreflex modulation device including one or more electrodes;

a control system operably coupleable to the baroreflex modulation device; and

instructions recorded on a tangible medium for operating the system so as to provide real-time feedback of a physiological parameter of a patient undergoing baroreflex therapy, the instructions including;

instructions to program the control system to deliver a therapy signal having a known parameter to the patient through the one or more electrodes of the baroreflex modulation device and to cause the control system to monitor with the one or more electrodes a resultant signal having a resultant parameter, determining one or more patient parameters based on the calculated impedance, and modifying the therapy signal based on the one or more patient parameters.