Process and device for determining the cardiac output

• US 6,102,869 A
• Filed: 03/12/1998
• Issued: 08/15/2000
• Est. Priority Date: 09/12/1995
• Status: Expired due to Fees

• Current Assignee: Heinemann & Gregori GmbH
• Original Assignee: Heinemann & Gregori GmbH
• Inventors: Heinemann, Helmut Otto, Foerster, Harald, Meier, Bernd Horst
• Primary Examiner(s): Hindenburg, Max
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US09/041,463
• Time in Patent Office: 887 Days
• Field of Search: 600/506, 600/547, 600/507, 600/526, 600/508, 600/513, 600/509, 607/28
• US Class Current: 600/506
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter

Abstract

Procedure and device for determining cardiac output volume which involves applying an electrical potential to create a current flow through tissue of the patient'"'"'s heart, placing a first measuring electrode on skin of the patient near the heart and inserting a second measuring electrode into the patient'"'"'s body at a position on an opposite side of the heart from the first measuring electrode so that a straight-line heart-traversing projection extends through the heart between the first and the second measuring electrodes. In one embodiment the second measuring electrode is in a blood vessel and in another embodiment there are a plurality of second measuring electrodes with the best one being determined by Electrocardiogram equipment.

Claims

1. Procedure of determining cardiac output volume of a heart of a patient by sensing a varying systolic impedance of tissue of the heart, with at least one first measuring electrode (B) and at least a second measuring electrode (E-L), said procedure including the steps of:

applying an electrical potential to the patient to thereby create a current flow through tissues of the heart;

placing the first measuring electrode on the skin of the patient near the heart;

inserting the second measuring electrode into a blood vessel at a position on an opposite side of the heart from the first measuring electrode so that a straight-line heart-traversing projection extending between the first and second measuring electrodes passes through the heart;

sensing the varying systolic impedance of the heart with the first and second measuring electrodes.

2. Procedure according to claim 1, wherein is further included a depiction step for producing a picture of the second measuring electrode and the heart to properly position the second measuring electrode inside the blood vessel.

3. Procedure according to claim 1, wherein an electrocardiographic vector signal is produced and displayed to properly position the second measuring electrode in the blood vessel.

4. Procedure according to claim 1, wherein the first and second measuring electrodes are used for recording an electrocardiogram.

5. Procedure according to claim 4, wherein a plurality of second measuring electrodes are arranged on a catheter, with each second measuring electrode registering on an electrocardiogram, and wherein these electrocardiogram registrations are used to determine a specific second electrode whose straight-line projection with the first measuring electrode provides the best indication of heart impedance, and wherein the impedance variables determined by this specific second electrode are used for determining cardiac output volume.

6. Procedure according to claim 5, wherein several first measuring electrodes are placed on the skin, with each second measuring electrode having a straight-line heart traversing projection with one of the first measuring electrodes for sensing the varying systolic impedance of the heart along said straight-line heart traversing projection.

7. Procedure according to claim 1, wherein said electrical potential is applied to the patient by using first and second current driving electrodes and wherein said first current driving electrode is applied to the skin close to an apex of the heart.

8. Procedure according to claim 7, wherein said electrical potential is applied by arranging first and second current driving electrodes in such a manner that the straight-line projection between the first and second measuring electrodes conforms closely to a current path between the current driving electrodes.

9. Device for determining cardiac output volume of a heart of a patient by sensing a varying systolic impedance of tissue of the heart, wherein is included:

at least one first measuring electrode for being placed on the skin of the patient near his heart and a plurality of second measuring electrodes for being inserted into a body vessel of the patient at positions on an opposite side of the heart from the first measuring electrode so that straight-line heart-traversing projections extending between the first and second measuring electrodes pass through the heart;

a means for applying an electrical potential to the patient to thereby create a current flow through tissues of the heart;

electrocardiogram equipment; and

cardiac output volume measuring equipment;

wherein said plurality of second measuring electrodes are arranged on a catheter, with each second measuring electrode being coupled to both the electrocardiogram equipment and the cardiac output volume measuring equipment, and wherein is further included a measuring means for evaluating electrocardiogram equipment registrations from the electrocardiogram equipment to determine a specific second electrode whose straight-line projection with the first measuring electrode provides the best indication of heart impedance and for then causing the cardiac output volume measuring equipment to use this specific second electrode to determine cardiac output volume.

10. Device according to claim 9, wherein the means for applying an electrical potential includes:

first and second current driving electrodes, with the first current driving electrode for being placed on the skin of the patient near his heart; and

an alternating current generator coupled to the first and second current driving electrodes.

11. Device according to claim 9, wherein the catheter is a tube-like catheter in which said plurality of second measuring electrodes are axially spaced therealong on an outer cover thereof, said tube-like catheter defining an axial suction canal which is open to outside the catheter.

12. Device according to claim 11, wherein the tube-like catheter further includes an axial working canal for receiving an endoscope.

13. Device according to claim 11, wherein the plurality of second measuring catheters are approximately-equally spaced from one another along the tube-like catheter, and are electrically insulated from one another.

14. Device according to claim 9, wherein the means for applying an electrical potential includes first and second current driving electrodes and wherein the catheter is a tube-like catheter in which said second measuring electrodes and said second current driving electrode are axially arranged, the second measuring electrodes being arranged closer to a free end of the tube-like catheter than is the second current driving electrode.

15. Device according to claim 9, wherein said measuring electrodes are connected by a frequency switch so that a low-frequency part of a measured signal is fed to the electrocardiogram equipment and a high-frequency, impedance-alteration-representing part of the measuring signal is fed to the cardiac output volume measuring equipment.