Temperature sensing return electrode pad

• US 7,927,329 B2
• Filed: 09/28/2006
• Issued: 04/19/2011
• Est. Priority Date: 09/28/2006
• Status: Expired due to Fees

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Covidien AG (Medtronic Plc)
• Inventors: McPherson, James W.
• Primary Examiner(s): Gibson; Roy D
• Assistant Examiner(s): SMITH, KAITLYN ELIZABETH
• Application Number:
  US11/529,007
• Publication Number:
  US 20080082092A1
• Time in Patent Office: 1,664 Days
• Field of Search: 606/32, 606/34, 606/35, 307/152
• US Class Current: 606/35
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• CPC Class Codes: A61B 18/16 Indifferent or passive electrodes for grounding
• CPC Class Codes: A61B 2018/00107 Coatings on the energy applicator
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00654 with individual control of each of a plurality of energy emitting elements
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00791 Temperature
• CPC Class Codes: A61B 2018/00797 measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/1253 monopolar
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61N 1/06 for high-frequency therapy

Abstract

An electrosurgical return electrode is disclosed. The return electrode includes a conductive pad having one or more temperature monitoring zones and a patient-contacting surface configured to conduct electrosurgical energy and a temperature sensing circuit coupled to the conductive pad. The temperature sensing circuit includes at least one diode disposed within the at least one temperature monitoring zone, the at least one diode having a predetermined forward voltage drop that is indicative of temperature of at least one temperature monitoring zone.

Claims

1. An electrosurgical return pad, comprising:

a conductive electrode including a plurality of temperature monitoring zones contiguously arranged therein and a patient-contacting surface configured to conduct electrosurgical energy;

a temperature sensing circuit thermally associated with each temperature monitoring zone, the temperature sensing circuit including at least one diode coupled in series with at least one resistor and disposed within each of the plurality of temperature monitoring zones, the at least one diode having a predetermined forward voltage drop that is indicative of an average temperature of the temperature monitoring zone associated with said at least one diode; and

an interconnection wire coupling each temperature sensing circuit to an optical isolation circuit adapted to isolate the temperature sensing circuit from electrosurgical energy.

2. An electrosurgical return pad according to claim 1, wherein the at least one diode is forward biased.

3. An electrosurgical return pad according to claim 1, further comprising a holding substrate for housing the temperature sensing circuit, the holding substrate being configured to electrically insulate the temperature sensing circuit from the patient-contacting surface.

4. An electrosurgical return pad according to claim 1, wherein the temperature sensing circuit is coupled to at least one power source configured to supply current to the at least one diode.

5. An electrosurgical return pad according to claim 4, wherein the at least one resistor is configured to limit the current flowing through the at least one diode to a predetermined level.

6. The electrosurgical return pad according to claim 1, wherein the pad includes an adhesive material disposed on the patient-contacting surface.

7. The electrosurgical return pad according to claim 1, wherein the pad is at least partially coated with a positive temperature coefficient (PTC) material.

8. A method for performing electrosurgery, comprising:

providing an electrosurgical return pad having a conductive electrode that includes a plurality of temperature monitoring zones contiguously arranged therein and a patient-contacting surface configured to conduct electrosurgical energy and a patient-contacting surface configured to conduct electrosurgical energy, and a temperature sensing circuit thermally associated with each temperature monitoring zone, the temperature sensing circuit including at least one diode coupled in series with at least one resistor and disposed within each of the plurality of temperature monitoring zones, the at least one diode having a predetermined forward voltage drop that is indicative of an average temperature of the temperature monitoring zone associated with said at least one diode, and an interconnection wire coupling each temperature sensing circuit to an optical isolation circuit adapted to isolate the temperature sensing circuit from electrosurgical energy;

placing the electrosurgical return pad in contact with a patient;

generating electrosurgical energy from an electrical energy source;

supplying the electrosurgical energy to the patient via an active electrode; and

monitoring the predetermined forward voltage drop to measure the temperature of the plurality of temperature monitoring zones.

9. A method according to claim 8, wherein the at least one diode is forward biased.

10. A method according to claim 8, further comprising a holding substrate for housing the temperature circuit, the holding substrate being configured to electrically insulate the temperature sensing circuit from the patient-contacting surface.

11. A method according to claim 8, further comprising the step of:

supplying current to the at least one diode.

12. A method according to claim 11, further comprising the step of:

limiting the current flowing through the at least one diode to a predetermined level.

13. A method according to claim 8, further comprising:

identifying a segment of the patient-contacting surface corresponding to a temperature monitoring zone wherein current density exceeds that of the surrounding area; and

instructing a user to take action with respect to the identified segment.

14. An electrosurgical system for performing electrosurgery, the electrosurgical system comprising:

an electrosurgical generator configured to provide electrosurgical energy;

an electrosurgical return pad including a conductive electrode including a plurality of temperature monitoring zones contiguously arranged therein and a patient-contacting surface configured to conduct electrosurgical energy, and a temperature sensing circuit thermally associated with each temperature monitoring zone, the temperature sensing circuit including at least one diode coupled in series with at least one resistor and disposed within each of the plurality of temperature monitoring zones, the at least one diode has a predetermined forward voltage drop that is indicative of an average temperature of the at least one temperature monitoring zone associated with said at least one diode, and an interconnection wire coupling each temperature sensing circuit to an optical isolation circuit adapted to isolate the temperature sensing circuit from electrosurgical energy; and

an active electrode to supply electrosurgical energy to a patient.

15. An electrosurgical system according to claim 14, wherein the at least one diode is forward biased.

16. An electrosurgical system according to claim 14, further comprising a holding substrate for housing the temperature sensing circuit, the holding substrate being configured to electrically insulate the temperature sensing circuit from the patient-contacting surface.

17. An electrosurgical system according to claim 14, wherein the temperature sensing circuit is coupled to at least one power source configured to supply current to the at least one diode.

18. An electrosurgical system according to claim 17, wherein the at least one resistor coupled in series with the at least one diode and configured to limit the current flowing through the at least one diode to a predetermined level.