Advanced thoracic fluid monitoring capability with impedance

• US 8,442,627 B2
• Filed: 12/30/2005
• Issued: 05/14/2013
• Est. Priority Date: 12/30/2005
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Hess, Michael F.
• Primary Examiner(s): Dougherty, Sean P
• Assistant Examiner(s): HENSON, DEVIN B
• Application Number:
  US11/322,700
• Publication Number:
  US 20070156061A1
• Time in Patent Office: 2,692 Days
• Field of Search: 600/547, 600/587, 600/595, 600/533, 600/536, 600/483, 607/9, 607/11, 607/19, 623/3.1, 623/3.28
• US Class Current: 600/547
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36535 controlled by body position or posture

Abstract

An implantable medical device used for thoracic fluid monitoring by detection of changes in impedance in a patient. The device measures impedances of the patient in a supine position and in an upright position. The device determines impedance differences between the supine and upright positions which correspond to a diurnal delta value, which may in turn be employed as a diagnostic parameter.

Claims

1. An implantable medical device for detection of changes in impedance in a patient, comprising:

means for measuring impedances corresponding to a supine patient position and for measuring impedances corresponding to an upright patient position;

means for generating a diurnal delta corresponding to the impedance differences between the supine and upright patient positions.

2. An implantable medical device according to claim 1, wherein the upright patient position is a period of time when the patient is likely in an upright position, and the supine patient position is a period of time when the patient is likely in a supine position.

3. An implantable medical device according to claim 1, wherein the upright and supine patient positions are the detected position of the patient based on sensor inputs.

4. An implantable medical device according to claim 1, wherein an alarm is initiated if the delta increases as compared to deltas generated in the past.

5. An implantable medical device according to claim 1, wherein an alarm is initiated if the delta decreases over a predetermined amount of time.

6. An implantable medical device according to claim 1, wherein the delta is the difference between the nighttime and daytime period average impedances.

7. An implantable medical device according to claim 1, wherein the delta is the difference between the nighttime and daytime integral differences, the integral differences being the integral of the difference between baseline impedances and period average impedances.