Cardiac Catheter And Shunt Electrode

Abstract

An elongated tubular catheter having a tube for discharging a liquid into a heart. A body of electrically conductive material is connected to the tube. The body has a passage for carrying liquid from a dispenser into the tube. An electrical plate electrode connected to the body with a line shunts electric current from the heart. The plate electrode is a disposable item having a flexible sheet base. An electrically conductive skin, as an aluminum sheet, is attached to one side of the base.

Parent Case Text

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U. S. application Ser. No. 92,767 filed Nov. 25, 1970, now U. S. Pat. No. 3,720,209. Application Ser. No. 92,767 is a continuation-in-part of U. S. patent application Ser. No. 711,949 filed Mar. 11, 1968, now U. S. Pat. No. 3,543,760 and U. S. patent application Ser. No. 866,630 filed Oct. 15, 1969, now U. S. Pat. No. 3,642,008.

Description

BACKGROUND OF INVENTION

The use of catheters in the human body provides potential for electrocution because the instruments can be conductors of electricity. Many of the electrocution accidents are caused by faulty equipment and people who fail to recognize the hazards. The remedy to this problem is to ground all elements of the system. Many factors make total grounding of all elements of the system at all times almost impossible. The plate electrode of the invention can be used with catheters and other electrical apparatus to reduce these electrocution hazards.

SUMMARY OF THE INVENTION

The invention relates to a catheter and electrical conductor means for carrying electrical current from the catheter. The catheter includes a tubular member and means having a passage and electrically conductive properties. A dispensing means discharges liquid through the passage and into the tubular member. The conductor means can be a disposable plate electrode connected to the means of the catheter to carry electrical current away from the catheter and liquid flowing through the catheter.

IN THE DRAWINGS

FIG. 1 is a diagrammatic view of a device having a cardiac catheter attached to a plate electrode located under the body of a patient positioned on a table; and

FIG. 2 is a diagrammatic view, partly sectioned, of the cardiac catheter and plate electrode of FIG. 1.

The disposable plate electrode shown in FIG. 1 is usable with a patient during surgery, catheterization and routine electrocardiography to ground and provide an alternate electrical circuit to the patient. The plate electrode is used to minimize the induction of ventricular fibrillation or multiple extra systoles when an electrical apparatus is connected to the patient. It is known that alternating current having 60 cycle per second frequency, as used in the United States of America, is among the most prone to cause ventricular fibrillation. The threshold of ventricular fibrillation with 60 cycle alternating current shocks administered to human hearts is very low, in the neighborhood of 180 microamperes. With a safety factor of 10, it has been found that shocks exceeding 2 microamperes of 60 cycle alternating current are regarded as hazardous if delivered directly to the human heart. Human studies indicate that 60 cycle shocks are 500 to 5000 times more dangerous when delivered directly to the heart rather than the body surface. The very small magnitude of the shocks capable of producing ventricular fibrillation may be appreciated in light of the observation that at 60 cycles currents less than one microampere cannot be detected through the skin. Saline of blood filled cardiac catheters and pacemaker electrodes are the usual means of gaining electrical access to the human heart.

To minimize the electrocution hazards, the voltage difference between the talbe and the patient and the apparatus or device which may be attached directly to the heart or any other part of the body must be eliminated or reduced to less than a few microamperes of current. In the present invention, the apparatus is connected to a disposable plate electrode in surface contact with the skin of the patient to shunt or bypass any electrical current that may flow between the apparatus and the patient's heart.

Referring to FIG. 1, there is shown a patient 300 located on a table 301. An electrical apparatus, indicated generally at 302, having an electrically conductive saline solution 303 is connected directly to the patient's heart 304 and a source of alternating current 305 used to operate the apparatus. The apparatus 302 comprises an intracardiac catheter 306. The catheter 306 is an elongated flexible plastic tube for carrying the saline solution 303 to one of the chambers of the heart 304. A coupling 307 is used to connect the catheter to a dye injector 311. The coupling 307 has an electrically conductive body 308 of metal or the like carrying an electrically insulative coating or skin 309. The dye injector 311 may be replaced with a densimeter or other apparatus for monitoring the condition of the heart.

As shown in FIG. 1, a plate electrode indicated generally at 312 is located on the table 301 in surface engagement with the back of the patient 300. The electrode 312, shown in FIG. 2, has a substantially flat base 313 of electrically insulative material, as cardboard. Secured to one side of the base 313 is an electrically conductive skin 314 of aluminum, tin, or similar conductive metal. The skin and base may be of the same materials as used in electrodes disclosed in U. S. Pat. No. 3,543,760. An electrical conductor 316, as a line or wire, is connected to a clamp 317. Clamp 317 is in engagement with skin 314. The line 316 is secured to the body 308 of the connector 307 and thereby electrically connects the fluid or saline liquid 303 with the electrode 312.

In use, the electrode 312 shunts or shorts away most of the current from the heart 304. The line 316 and electrode 312 together have less resistance to the current than the saline liquid in the catheter 306. The ratio of resistance between the line 316 and electrode 312 together compared to saline column in the catheter 306 is between 300 and 500 to 1. This ratio depends upon the diameter and/or length of the saline column. Accordingly, the amount of current applied to the heart is reduced by this factor. The plate electrode 312 along with the connecting line 316 in electrical contact with the saline liquid 303 will substantially reduce the incidence of ventricular fibrillation of the heart 304.

While there has been shown and described a disposable plate electrode for use with an intracardiac catheter, it is intended that the electrode can be used with other electrical apparatus to ground a patient.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination: a cardiac catheter having a tube adapted to carry a liquid to a patient's heart, means to supply liquid to said tube, electrode means having an electrically conductive surface adapted to engage an area of the patient's body, and electrical conductor means electrically connecting the surface of the electrode means with the liquid in the catheter whereby substantially all electric currents are shunted around the heart.

2. The structure of claim 1 wherein: the electrical conductor means includes a body having a passage connected to the tube, said body being made of electrically conductive material.

3. The structure of claim 2 including: an electrically insulative skin means covering the outside of the body.

4. The structure of claim 1 wherein: said electrode means is a sheet member having an electrically conductive skin.

5. The structure of claim 1 wherein: said electrode means is a sheet member having a generally flat flexible base and electrically conductive skin secured to one side of the base.

6. The structure of claim 1 including: clamp means connecting the conductor means to the electrode means.

7. A catheter and electrical conductor means for shunting electrical current away from the catheter comprising: a tubular member having a longitudinal passage for carrying fluid, means having a passage connected to the tubular member, said passage of the means being in communication with the passage in the tubular member whereby fluid can flow through the tubular member and body means, said means being made of electrically conductive material, electrode means for carrying electric current, and electrical conductor means connecting the means and the electrode means whereby electric power is shunted away from the tubular member.

8. The structure of claim 7 wherein: said electrode means is a sheet member having an electrically conductive skin.

9. The structure of claim 7 wherein: said electrode means is a sheet member having a generally flat flexible base and electrically conductive skin secured to one side of the base.

10. The structure of claim 7 including: clamp means connecting the conductor means to the electrode means.

11. The structure of claim 7 including: means connected to the means having a passage operable to dispense fluid through the passage.