Implantable Medical Device and Methods for Automated Detection of Infection

• US 20080064980A1
• Filed: 08/03/2007
• Published: 03/13/2008
• Est. Priority Date: 09/08/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Belalcazar, Hugo Andres, Lee, Kent, Heil, Ronald W., Kwok, Jonathan T., Pavlovic, Jennifer Lynn
• Granted Patent: US 8,583,224 B2
• Time in Patent Office: Days
• US Class Current: 600/547
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/036 by means introduced into body tracts A61B5/032 and A61B5/035 take precedence
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance

Abstract

The invention relates to systems, devices, and methods for detecting infections associated with implantable medical devices. In an embodiment, the invention includes a method of detecting infection in a patient including measuring a physiological parameter using a chronically implanted sensor at a plurality of time points and evaluating the physiological parameter measurements to determine if infection is indicated. In an embodiment, the invention includes an implantable medical device including a first chronically implantable sensor configured to generate a first signal corresponding to a physiological parameter and a controller disposed within a housing, the controller configured to evaluate the first physiological parameter signal to determine if an infection is indicated. Other embodiments are also included herein.

Claims

1. A method of detecting infection in a patient comprising:

measuring a physiological parameter using a chronically implanted sensor at a plurality of time points; and

evaluating the physiological parameter measurements to determine if infection is indicated.

2. The method of claim 1, the physiological parameter is selected from the group consisting of impedance through tissue, temperature, pH, pressure, C-reactive protein concentration, lactate concentrations, lipopolysaccharide concentration, procalcitonin concentration, interleukin-6 concentration, interleukin-8 concentration, serum amyloid A concentration, tumor necrosis factor alpha concentration, and white blood cell count.

3. The method of claim 1, the physiological parameter comprising impedance measured between a stimulation lead and a housing surface of an implanted medical device.

4. The method of claim 1, the physiological parameter comprising impedance, wherein infection is indicated by a decline in the average impedance.

5. The method of claim 1, further comprising initiating therapy to treat infection if infection is indicated.

6. The method of claim 5, the therapy comprising administration of an anti-microbial active agent.

7. The method of claim 5, the therapy comprising initiation of anti-microbial electrical therapy.

8. The method of claim 5, further comprising evaluating the physiological parameter measurements to determine if infection is clearing.

9. The method of claim 1, wherein evaluating the physiological parameter measurements comprises determining a baseline value for the physiological parameter and comparing a current measurement to the baseline value.

10. The method of claim 9, wherein infection is indicated if the current measurement of the physiological parameter differs from the baseline value by at least a threshold amount.

11. The method of claim 1, further comprising providing a notification if infection is indicated.

12. The method of claim 11, wherein providing a notification comprises providing a warning indication to a medical professional via a signal transmitted to a non-implanted device.

13. The method of claim 1, further comprising evaluating the physiological parameter measurements to determine whether or not sepsis is occurring.

14. The method of claim 1, further comprising displaying data regarding the physiological parameter on an external device.

15. An implantable medical device comprising:

a first chronically implantable sensor configured to generate a first signal corresponding to a physiological parameter;

a controller disposed within a housing, the controller configured to evaluate the first physiological parameter signal to determine if an infection is indicated.

16. The implantable medical device of claim 15, the first chronically implantable sensor comprising a sensor selected from the group consisting of an impedance sensor, a temperature sensor, a pressure sensor, a pH sensor, and a chemical species sensor.

17. The implantable medical device of claim 15, the first chronically implantable sensor comprising an impedance sensor.

18. The implantable medical device of claim 15, the first chronically implantable sensor disposed on the housing.

19. The implantable medical device of claim 15, the processing unit configured to store a detection threshold, where the implantable medical device is configured to compare the signal from the first chronically implantable sensor to the detection threshold to determine whether an infection is present.

20. The device of claim 19, wherein the detection threshold varies as a function of time after the implantable medical device is implanted.

21. The device of claim 20, wherein the threshold is lower during periods of time when the patient is at increased risk of developing an infection.

22. The device of claim 20, further comprising a reservoir and an anti-microbial active agent disposed within the reservoir, the device configured to release the anti-microbial active agent from the reservoir if an infection is indicated.

23. The device of claim 21, the anti-microbial active agent comprising an antibiotic.

24. The device of claim 21, where the implantable medical device further includes memory configured to store a treatment threshold, where the implantable medical device is configured to compare the signal from the sensor to the treatment threshold to determine the efficacy of any medical treatments initiated after an infection is detected.