Impedance spectroscopy system and catheter for ischemic mucosal damage monitoring in hollow viscous organs

• US 6,882,879 B2
• Filed: 07/18/2001
• Issued: 04/19/2005
• Est. Priority Date: 07/19/2000
• Status: Expired

• Current Assignee: Critical Perfusion, Inc.
• Original Assignee: Innovamedica S.A. De C.V.
• Inventors: Rock, Emilio Sacristán
• Primary Examiner(s): Robinson, Daniel
• Application Number:
  US09/907,781
• Publication Number:
  US 20020013537A1
• Time in Patent Office: 1,371 Days
• Field of Search: 600/547, 600/898, 600/300, 600/506, 600/536, 604/508, 604/500, 324/600, 324/601, 324/602, 324/609, 324/643, 324/644
• US Class Current: 600/547
• 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 5/053 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 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/42 Detecting, measuring or recording for evaluating the gastrointestinal, the endocrine or the exocrine systems A61B1/00, A61B5/4857, A61B5/486, A61B5/4866, A61B5/4869 take precedence
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00

Abstract

An impedance spectroscopy system for monitoring ischemic mucosal damage in hollow viscous organs comprises a sensor catheter and an impedance spectrometer for electrically driving the catheter to obtain a complex tissue impedance spectrum. Once the catheter is in place in one of a patient'"'"'s hollow viscous organs, the impedance spectrometer obtains the complex impedance spectrum by causing two electrodes in the tip of the catheter to inject a current into the mucosal tissue at different frequencies, while two other electrodes measure the resulting voltages. A pattern recognition system is then used to analyze the complex impedance spectrum and to quantify the severity of the mucosal injury. Alternatively, the complex impedance spectrum can be appropriately plotted against the spectrum of normal tissue, allowing for a visual comparison by trained personnel.

Claims

1. A catheter for use in a system for monitoring mucosal damage in hollow viscous organs, said catheter comprising:

a. a length of tubing suitable for insertion into hollow viscous organs;

b. a plurality of electrodes disposed proximate a distal end of the tubing; and

c. a plurality of electrical leads respectively electrically connected to the plurality of electrodes and extending through the tubing to a proximal end thereof;

wherein;

d. the electrodes each comprise;

a cylindrical central portion having an annular side wall and a diameter generally equal to an outer diameter of the tubing;

first and second cylindrical extensions attached to a top and a bottom of the cylindrical central portion, respectively, and coaxial therewith, said first and second cylindrical extensions having a diameter smaller than the diameter of the cylindrical central portion; and

an axial bore extending through the cylindrical central portion and first and second cylindrical extensions; and

e. the electrodes are spaced apart from one another by annular spacers positioned over the cylindrical extensions and abutting the cylindrical central portions.

2. The catheter of claim 1 further comprising a fill extending through the spacers and axial bores of the electrodes.

3. A catheter for use in a system for monitoring mucosal damage in hollow viscous organs, said catheter comprising:

a. a length of tubing suitable for insertion into hollow viscous organs;

b. a plurality of electrodes disposed proximate a distal end of the tubing; and

c. a plurality of electrical leads respectively electrically connected to the plurality of electrodes and extending through the tubing to a proximal end thereof;

wherein;

d. the electrodes each comprise;

a cylindrical central portion having an annular side wall and a diameter generally equal to an outer diameter of the tubing;

first and second cylindrical extensions attached to a top and a bottom of the cylindrical central portion, respectively, and coaxial therewith, said first and second cylindrical extensions having a diameter smaller than the diameter of the cylindrical central portion; and

an axial bore extending through the cylindrical central portion and first and second cylindrical extensions; and

e. the electrodes are spaced apart from one another by annular spacers positioned over the cylindrical extensions and abutting the cylindrical central portions, wherein;

i. the spacers each have two annular, inwardly-facing shoulders spaced back from the ends of the spacers; and

f. the cylindrical extensions of the electrodes each have an annular lip facing towards the cylindrical central portions, wherein the cylindrical extensions are dimensioned to fit within the spacers such that the lips abut the shoulders, locking the electrodes to the spacers.

4. The catheter of claim 3 further comprising a fill extending through the spacers and axial bores of the electrodes.

5. A catheter for use in a system for monitoring mucosal damage in hollow viscous organs, said catheter comprising:

a. a tip having a rounded fore portion and a projection extending back from the fore portion;

b. a plurality of electrodes each having;

an annular side surface; and

a through-bore extending through the electrode and complementary in shape to the projection;

c. at least one spacer having;

an annular side surface; and

a through-bore extending through the spacer and complementary in shape to the projection;

d. a length of tubing suitable for insertion into hollow viscous organs; and

e. a plurality of electrical leads respectively electrically connected to the plurality of electrodes;

wherein;

f. the electrodes are positioned over the projection with the projection extending through the electrode through-bores, said electrodes being spaced apart from one another by the at least one spacer being positioned therebetween and over the projection with the projection extending through the spacer through-bore; and

g. a rear portion of the projection lies inserted within the tubing, with the electrodes and at least one spacer being positioned between the rounded fore portion of the tip and an end of the tubing.

6. The catheter of claim 5 wherein the through-bores and the projection are both V-shaped.

7. The catheter of claim 5 wherein the through-bores and the projection both have a rounded trough shape.

8. The catheter of claim 5 wherein:

a. each electrode further comprises a passageway extending through the electrode;

b. the at least one spacer further comprises a passageway extending through the spacer; and

c. the electrical leads extend through the electrode and spacer passageways.

9. The catheter of claim 5 wherein there are four electrodes and three spacers.

10. In a catheter for use in a system for monitoring mucosal damage in hollow viscous organs, wherein the catheter includes a length of tubing suitable for insertion into hollow viscous organs, a plurality of electrodes disposed proximate a distal end of the tubing, the improvement comprising:

a. a plurality of electrical leads respectively electrically connected to the plurality of electrodes and extending through the tubing to a proximal end thereof;

b. a plurality of annular spacers adapted in size and shave to be mounted on the catheter, and,

c. means for interconnecting adjacent spaced apart pairs of the spacers with electrodes snap locking into the pairs, wherein;

i. the interconnecting electrodes each have cylindrical central portions with two annular side walls and a diameter generally equal to an outer diameter of the tubing sections;

first and second cylindrical extensions attached to a top and a bottom of the cylindrical central portion, respectively, and coaxial therewith, said first and second cylindrical extensions having a diameter smaller than the diameter of the cylindrical central portion; and

an axial bore extending through the cylindrical central portion and first and second cylindrical extensions; and

ii. the extensions fit into through-bores of the spacers.