Catheter for spinal epidural injection of drugs and measurement of evoked potentials

• US 5,081,990 A
• Filed: 05/11/1990
• Issued: 01/21/1992
• Est. Priority Date: 05/11/1990
• Status: Expired due to Fees

• Current Assignee: New York University
• Original Assignee: New York University
• Inventors: Deletis, Vedran
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Getzow, Scott M.
• Application Number:
  US07/522,008
• Time in Patent Office: 620 Days
• Field of Search: 128/642, 128/784, 128/785, 128/786, 128/740, 128/741, 128/905, 128/739
• US Class Current: 600/555
• CPC Class Codes: A61B 17/3401 Puncturing needles for the peridural or subarachnoid space or the plexus, e.g. for anaesthesia local anaesthesia A61M19/00
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes

Abstract

An spinal epidural catheter apparatus and method are shown and described. The apparatus provides for injection of drugs into the spinal epidural area, and measurement of evoked potentials at the point of injection by means of electrodes located on the tip of the catheter and a voltage detector connected to the free end of the catheter.

Claims

1. A method for determining the effect of epidurally administered drugs on the spinal cord electrical activity of an animal, comprising the steps of:

(1) insertion of a catheter into the epidural space of the spinal cord, said catheter having at least two electrodes and a means for injecting drugs;

(2) administration of a drug through said catheter into the epidural space;

(3) administering an electrical stimulus to the animal;

(4) detecting the evoked response at the electrodes of said catheter; and

(5) comparing said detected response with the response detected in the same animal when drugs have not been inserted into the epidural space.

2. A method in accordance with claim 1, wherein the animal is a human.

12. A device in accordance with claim 13, wherein said second electrode means includes at least two electrodes, each being separately electrically connectable to the external electrical transmission or reception device.

13. A device in accordance with claim 2, wherein the animal is a human.

3. A device for epidurally administering a drug to the spine of an animal and measuring spinal cord electrical activity, comprising:

a catheter sized and dimensioned for insertion into the spinal epidural space and having a distal tip and a proximal end, said catheter having drug passage means for passage of a drug through the catheter and including an outlet opening for allowing the drug to exit the catheter into the epidural space when the catheter is in use, and said catheter further having first electrode means and second electrode means, both being connectable by means of separate electrical connections within the catheter to an external electrical transmission or reception device, wherein said first electrode means is disposed at or near the distal tip of the catheter and distal to said outlet opening, and said second electrode means is disposed proximal to said outlet opening.

4. A device in accordance with claim 3, wherein the portion of said catheter intended to be inserted into the spinal epidural space when in use is small enough to pass through a 15-gauge epidural needle.

5. A device in accordance with claim 3, wherein the portion of said catheter intended to be inserted into the spinal epidural space when in use is small enough to pass through an 18-gauge epidural needle.

6. A device in accordance with claim 3, wherein said first electrode means includes at least two electrodes, each being separately electrically connectable to the external electrical transmission or reception device.

7. A device in accordance with claim 6, wherein one electrode of said first electrode means is disposed at the distal tip of the catheter and each additional electrode of said first electrode means is disposed approximately one centimeter from the electrode next distal thereto.

8. A device in accordance with claim 7, wherein said drug passage means outlet opening is disposed about 2 to about 20 cm proximal to the electrode farthest from the distal tip of the catheter.

9. A device in accordance with claim 3, wherein said catheter is sized and dimensioned for insertion into the spinal epidural space of a human patient.

10. A method for monitoring the effect of spinal epidural anaesthesia using a device for epidurally administering a drug to the spine of an animal and measuring spinal cord electrical activity, comprising:

a catheter sized and dimensioned for insertion into the spinal epidural space and having a distal tip and a proximal end, said catheter having drug passage means for passage of a drug through the catheter and including an outlet opening for allowing the drug to exit the catheter into the epidural space when the catheter is in use, and said catheter further having first electrode means and second electrode means, both being connectable by means of separate electrical connections within the catheter to an external electrical transmission or reception device, wherein said first electrode means is disposed at or near the distal tip of the catheter and distal to said outlet opening, and said second electrode means is disposed proximal to said outlet opening, said method comprising;

inserting the catheter into the spinal epidural space of the animal to be anesthetized until the drug passage means outlet opening is at the desired location;

administering anaesthetic via said drug passage means, through said outlet opening, into the epidural space;

applying triggered electrical stimuli by means of one of said first and second electrode means;

measuring the evoked potential at the other of said first and second electrode means; and

adjusting the amount of anaesthetic being administered dependent on the nature of the measured evoked potential to assure that sufficient anaesthetic is being administered for the desired anaesthetic effect without overloading the animal with anaesthesia.

11. A method in accordance with claim 10, wherein the animal is a human.

14. A method for monitoring the effect on an animal of spinal epidural anaesthesia using a device comprising a catheter sized and dimensioned for insertion into the spinal epidural space of the animal to be anesthetized, said catheter having drug passage means for passage of a drug through the catheter and including an outlet opening for allowing the drug to exit the catheter into the epidural space when the catheter is in use, and said catheter further having first electrode means disposed at or near the distal tip of the catheter, said first electrode means being connectable by means of an electrical connection within the catheter to an external electrical transmission or reception device, the method comprising:

inserting the catheter into the spinal epidural space of the animal to be anesthetized until the drug passage means outlet opening is at the desired location;

administering anaesthetic via said drug passage means, through said outlet opening, into the epidural space;

applying triggered electrical or mechanical stimuli to the animal;

measuring the evoked potential at said electrode means; and

adjusting the amount of anaesthetic being administered dependent on the nature of the measured evoked potential to assure that sufficient anaesthetic is being administered for the desired anaesthetic effect without overloading the animal with anaesthesia.

15. A method in accordance with claim 14, wherein the animal is a human.