System for monitoring integrity of a patient return circuit

• US 4,121,590 A
• Filed: 03/14/1977
• Issued: 10/24/1978
• Est. Priority Date: 03/14/1977
• Status: Expired due to Term

• Current Assignee: Dentsply Research & Development Corporation (Astrazeneca PLC)
• Original Assignee: Dentsply Research & Development Corporation (Astrazeneca PLC)
• Inventors: Gonser, Donald I.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US05/777,330
• Time in Patent Office: 589 Days
• Field of Search: 128/303.13, 128/303.14, 128/303.17, 128/303.18, 128/2.1 P, 307/326, 323/9, 328/7
• US Class Current: 606/35
• CPC Class Codes: A61B 18/16 Indifferent or passive electrodes for grounding
• CPC Class Codes: Y10S 323/911 Medical electronics

Abstract

A monitor for a patient return circuit of a radiofrequency electrosurgical device in which an interrogation or measurement circuit is powered by a photovoltaic cell. Characteristics of the photovoltaic cell can limit the interrogation or measurement current to a value considered to be safe to a patient.

Claims

1. A system for monitoring the integrity of a patient intended return of a radiofrequency electrosurgical device including a passive electrode and a return lead means attached to the passive electrode, said system comprising a monitoring circuit including said passive electrode, said return lead means, a photovoltaic cell, and current sensing means, said passive electrode, said return lead means, said photovoltaic cell, and said current sensing means being connected in series, means for illuminating the photovoltaic cell, and means actuated by the current sensing means for indicating a discontinuity in the monitering circuit, the voltage in the monitoring circuit being limited by the limiting voltage of the photovoltaic cell.

2. A system as in claim 1 wherein the monitoring circuit includes radiofrequency inductance means isolating the photovoltaic cell and the current sensing means from the passive electrode and the return lead means.

3. A system as in claim 1 wherein the monitoring circuit includes a second return lead means connected to the passive electrode, the passive electrode, the second return lead means, the return lead means, the photovoltaic cell, and the current sensing means are connected in series, the return lead means is coupled to ground, and capacitor means couples the second return lead means and the return lead means.

4. A system as in claim 3 wherein the passive electrode includes two sections, the return lead means is connected to one of the sections, and the second return lead means is connected to the other section.

5. The combination of a radiofrequency electrosurgical device which includes a radiofrequency generator, an active electrode, means actuated by the radiofrequency generator for supplying radiofrequency current to the active electrode, a passive electrode and a return lead means attached to the passive electrode for returning radiofrequency current to the generator with a monitoring circuit including said passive electrode, said return lead means, a photovoltaic cell, and current sensing means, said passive electrode, said return lead means, said photovoltaic cell, and said current sensing means being connected in series, means for illuminating the photovoltaic cell, means actuated by the current sensing means for indicating a discontinuity in the monitoring circuit, and means activated by the current sensing means to disable the radiofrequency generator from supplying radiofrequency current to the active electrode when indicating the discontinuity, the voltage in the monitoring circuit being limited by the limiting voltage of the photovoltaic cell.

6. The combination of a radiofrequency electrosurgical device which includes a radiofrequency generator, an active electrode, means actuated by the radiofrequency generator for supplying radiofrequency current to the active electrode, a passive electrode and a return lead means attached to the passive electrode returning radiofrequency current to the generator with a monitoring circuit including said passive electrode, said return lead means, a photovoltaic cell, and current sensing means, said passive electrode, said return lead means, said photovoltaic cell, and said current sensing means being connected in series, means for illuminating the photovoltaic cell, means actuated by the current sensing means for indicating a discontinuity in the monitoring circuit, a warning device and means activated by the current sensing means to activate the warning device when indicating the discontinuity, the voltage in the monitoring circuit being limited by the limiting voltage of the photovoltaic cell.

7. A system for monitoring the integrity of a patient return of a radiofrequency electrosurgical device which includes a passive electrode including a pair of sections, a first return lead means connected to one of said sections, a second return lead means connected to the other of said sections, a photovoltaic cell and a current sensing means connected in series between the first return lead means and the second return lead means, means for illuminating the photovoltaic cell, and means actuated by the current sensing means for indicating a discontinuity in the lead means, the voltage in the monitoring system being limited by the limiting voltage of the photovoltaic cell.

8. A system as in claim 7 which includes radiofrequency inductance means isolating the photovoltaic cell and the current sensing means from the passive electrode sections, the first return lead means and the second return lead means.

9. A system as in claim 7 which includes capacitor means coupling the first return lead means and the second return lead means.

10. The combination of a radiofrequency electrosurgical device which includes a radiofrequency generator, an active electrode, means actuated by the radiofrequency generator for supplying radiofrequency current to the active electrode, a passive electrode including a pair of sections, a first return lead means connected to one of said sections, and a second return lead means connected to the other of said sections, said lead means for returning radiofrequency current to the generator with a monitoring circuit which includes the passive electrode, the first return lead means, the second return lead means, a photovoltaic cell and a current sensing means, the photovoltaic cell and the current sensing means being connected in series between the first return lead means and the second return lead means, means for illuminating the photovoltaic cell, means actuated by the current sensing means for indicating a discontinuity in the lead means, and means activated by the current sensing means to disable the radiofrequency generator from supplying radiofrequency current to the active electrode when indicating the discontinuity, the voltage in the monitoring circuit being limited by the limiting voltage of the photovoltaic cell.

11. The combination of a radiofrequency electrosurgical device which includes a radiofrequency generator, an active electrode, means actuated by the radiofrequency generator for supplying radiofrequency current to the active electrode, a passive electrode including a pair of sections, a first return lead means connected to one of said sections, and a second return lead means connected to the other of said sections, said lead means for returning radiofrequency current to the generator, with a monitoring circuit which includes the passive electrode, the first return lead means, the second return lead means, a photovoltaic cell and a current sensing means, the photovoltaic cell and the current sensing means being connected in series between the first return lead means and the second return lead means, means for illuminating the photovoltaic cell, means actuated by the current sensing means for indicating a discontinuity in the lead means, a warning device, and means activated by the current sensing means to activate the warning device when indicating the discontinuity, the voltage in the monitoring circuit being limited by the limiting voltage of the photovoltaic cell.