JPH0292351A - High frequency cautery power supply device for endoscope - Google Patents

Abstract

PURPOSE:To reduce the leak current flowing from an endoscope to an operator and an examinee as low as possible by automatically changing over the impedance inserted between a P-electrode and the endoscope in response to a change of a monitor state by an impedance change-over means. CONSTITUTION:The terminal voltage of a cautery power supply detected by a voltage detection circuit 13 is converted to a detection signal shown as an absolute value by an absolute value circuit 15 to be sent to one of the input terminals of a divider circuit 17. The scope earth potential detected by a voltage detection circuit 14 is converted to a detection signal shown as an absolute value by an absolute value circuit 16 to be sent to the other input terminal of the divider circuit 17. By this method, the mutual division of the outputs of the absolute value circuits 15, 16 is performed in the divider circuit 17 and the division output is sent to a control circuit 18 which in turn controls the driving of a change-over circuit 12 and that of alarms 19, 20. That is, on the basis of the division result of the divider circuit 17, an impedance inserting condition reducing a scope leak current, pref. bringing said current to zero is set.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) Regarding the high-frequency ablation power supply device for endoscopes used in combination with the Jl scope device, improvement of the high-frequency ablation power supply device for endoscopes that has a function of preventing high-frequency current from flowing to unintended locations through the endoscope scope. Regarding.

(Conventional technology) In recent years, radiofrequency ablation using an endoscope has the great advantage of being able to perform procedures with less burden on the patient and operator, and has been used to treat diseased areas within the patient's body cavity. It has come to be used frequently to incise and coagulate specific parts of the body.

However, on the other hand, because the treatment is applied to areas with high current density by applying high-frequency current, if high-frequency leakage current flows to areas unintended by the examinee or surgeon, burns may occur in the unintended areas. There is a possibility that this may occur.

Therefore, conventional high-frequency ablation devices for endoscopes use a so-called floating method, which allows the output terminal of the ablation power source to be electrically floated above the ground. .

However, even if the floating method is applied, it is not possible to completely electrically float the output terminal of the ablation power source above the ground, and for example, the A pole (treatment side electrode) and P pole (subject The mounting side electrodes, ) are both electrically connected through stray capacitance, etc. Further, the treatment instrument and the endoscope are electrically connected by stray capacitance or the like.

For these reasons, with conventional endoscopic high-frequency ablation devices of this type, high-frequency leakage current flows through the endoscope to areas unintended by the operator or patient, resulting in burn accidents. There was a risk.

Therefore, further improved measures to prevent burn accidents have been proposed and put into practical use. This measure to prevent burn accidents is a technology called the so-called S code system, and for example, as shown in FIG. By connecting the return code (S code) 4, the endoscope scope 3 is connected to the P pole 2.
Make it the same potential as. In other words, the endoscope 3 serves as the second return electrode. In addition, 5 is the A pole, 6
is an A code, 7 is a treatment instrument, 8 is a return electrode, and 9 is a P code.

In this case, when an excessive current flows through the endoscope 3, this current can be returned to the P pole 2, reducing the risk of burn injuries compared to the conventional floating method. did.

(Problems to be Solved by the Invention) However, in the case of an endoscopic high-frequency ablation device to which the conventional S-code system is applied, the operator touching the ground or the subject's living body during the initial energization When tissue or the like touches the exposed metal part of the scope, it is electrically connected to the A pole in some way, and a leakage current flows, for example, at the part 2 and 0 in FIG. In this case, there was a risk that burns would occur due to ■ and ■.

The present invention has been made in view of the above-mentioned problems, and its purpose is to automatically adjust the leakage current flowing from the endoscope through the operator, the patient, etc. as much as possible. An object of the present invention is to provide a high-frequency ablation power supply device for an endoscope that can perform the following.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention provides an endoscope having a function of preventing high-frequency current from flowing to an unintended location through an endoscope. A high-frequency ablation power supply device for a mirror, which includes an impedance switching means that can variously change the magnitude of impedance inserted between the P pole and the endoscope, and a potential that monitors the ablation power supply terminal voltage and the scope ground potential, respectively. a monitoring means, a condition setting means for setting an impedance insertion condition under which scope leakage current is reduced based on a detection signal according to the ablation power supply terminal voltage and a detection signal according to the scope ground potential from the potential monitoring means; The gist of the present invention is to include an ablation environment control means for controlling the ablation environment by switching and controlling the impedance switching means in accordance with the impedance insertion conditions set by the condition setting means.

(Function) In the high-frequency ablation power supply device for an endoscope according to the present invention, the ablation power supply voltage and scope-to-ground potential are monitored during the high-frequency ablation process, and the impedance is automatically adjusted in response to changes in the monitoring status. Since the impedance inserted between the P pole and the endoscope is switched by the switching means, the leakage current flowing from the endoscope to the operator, patient, etc. can be minimized, and in principle, can be made zero.

(Embodiment) Fig. 1 is a circuit diagram schematically showing a high-frequency ablation power supply device for an endoscope according to an embodiment of the present invention, and Fig. 2 is a circuit diagram showing the high-frequency ablation power supply device for an endoscope according to an embodiment of the present invention. FIG.

The high-frequency ablation power supply device 1 for an endoscope according to this embodiment has a second
A\i5. It operates while connected to the P pole 2 and the S pole 10. An impedance element group 11 is provided between the P pole 2 and the S pole 10, and in order to switch the impedance element group 11 by a switching circuit 12, a voltage detection circuit 13. 14, and absolute value circuit 15. Same 1
6, a division circuit 17, and a control circuit 18.

Further, 19 and 20 are alarm devices, 21 is a cautery power source, and 22 and 23 are capacitors for cutting off DC.

The ablation power supply terminal voltage detected by the voltage detection circuit 13 is converted into a detection signal represented by an absolute value by the absolute value circuit 15 and sent to one input terminal of the division circuit 17 .

On the other hand, the scope ground potential detected by the voltage detection circuit 14 is converted into a detection signal represented by an absolute value by the absolute value circuit 16 and sent to the other input terminal of the division circuit 17.

As a result, the outputs of the absolute value circuits 15 and 16 are mutually divided in the division circuit 17, and the result of this division is sent to the control circuit 18.

The control circuit 18 includes the switching circuit 12. Alarm 19 and 20
It is used to drive and control the That is, it functions as a condition setting means for setting an impedance insertion condition under which the scope leakage current is reduced based on the division result of the division circuit 17, preferably an impedance insertion condition under which the scope leakage current becomes zero, and this condition setting means The switching circuit 12 is controlled and operated according to the impedance insertion conditions.
It has a function as an ablation environment control means for controlling the ablation environment by switching and controlling the impedance element group 11.

Furthermore, there is a drive control function for causing an alarm 19 to notify an abnormality when the P pole 2 contacts the exposed metal end (not shown) of the endoscope 3, and a drive control function for causing the alarm 19 to notify an abnormality when the P pole 2 contacts the exposed metal end (not shown) of the endoscope 3. It also has a drive control function for causing the alarm 20 to issue an abnormality notification upon contact with the exposed metal end.

Since this embodiment of the high-frequency ablation power supply device for an endoscope is equipped with such various parts, it functions as described below.

FIG. 3 is an equivalent circuit diagram when the S cord 4 from the endoscope 3 is not connected to the S pole 10 when the conventional floating type operation is performed.

In the case of this floating method, when there is no leakage current from the endoscope scope 3, the potential 9 of the point S of the endoscope scope 3
s is equal to the potential 9o of the A pole 5.

and,! Potential MR not equal to 0 (however, QR to 90
) when point R contacts point S, current flows between S and R because IQs-QRI.

Therefore, when the exposed metal part of the scope comes into contact with the living tissue of the operator or the subject, there is a high risk of burns because the contact part comes into contact with the A pole in some way.

Figure 4 shows that when operating according to the conventional S code method and making the necessary connections, the endoscope scope 3 is connected to the S pole 10.
2 is an equivalent circuit diagram in the case where the S cord 4 from the above is connected, but the S pole 10 and the P pole 2 are connected without intervening any impedance element.

In the case of this S code system, the endoscope 3 has the same potential as the P pole 2, so the potential is Vs -0.

Therefore, when point R contacts point S, l Qs −QR−
1vR1 to 0, a current flows between S and R, and since the contact site is the same as if it had somehow touched the A pole, there is a risk of burns occurring.

In this respect, as in the present invention, the S cord 4 from the endoscope 3 is connected to the S pole 10, and the impedance switching function allows changing the magnitude of the impedance inserted between the S pole 10 and the P pole. If a means is provided, the equivalent circuit in this case will be as shown in FIG. 5, and the problems of the conventional floating system and S code system can be avoided.

That is, if the relationship of the equivalent circuit shown in FIG. 5 exists, the matching impedance ZM can be expressed as
By choosing Vo -1'R, Qs-QR can be obtained.

Therefore, it can be set to l ts −VRl −0,
No current will flow between S and R.

More specifically, by configuring the high-frequency ablation power supply device as shown in FIG. 1 and connecting the circuits as shown in FIG. 2, it operates as follows.

The processing tool 7 and the endoscope 3 are coupled through a capacitance Cs, as shown in the equivalent circuit of FIG.
Furthermore, the matching impedance CR provided by the impedance element group 11 is connected.

Now, there is no leakage current from the endoscope 3.
12, the matching impedance CR is Ck-[\7o/(\i5-1) ko・CS
Therefore, Ck = [Vo / (Vs 1)] ・Cs
It is.

According to this formula, Qo with f+=f2 as a parameter
The characteristic curve showing the relationship between / (Qs -1) and Ck is as shown in FIG. Therefore, on the same diagram, 1l
The t+>12 region and the f+<f2 region can be separately represented by the parameter =f2.

That is, when f+>12, Qo/(Vs -1) becomes larger than in the case of 11-12 where there is no leakage current,
Also, when f+>f2, there is no leakage current! Vo/(<75 −1) is smaller than in the case of −12.

Therefore, in one embodiment of the present invention, a plurality of matching impedances Ck are prepared by the impedance element group 11, and each cover area is different.

For example, as shown in FIG. 8, for one Ck, Qo/(Qs
1) Cover the large area Y.

Now, when Vo/(Qs-1)<b is smaller than the b value which is the minimum Qo/(V5-1) value of region Y, Ck is switched to the one with a smaller capacitance.

Also, C which is the maximum Vo/(Vs 1) value of area Y
When Vo/(951)<c is larger than the value, Ck is switched to the one with a larger capacitance than the current one.

By doing this, when the leakage current from the endoscope 3 becomes small regardless of Ck, in other words, what kind of Ck should be selected so that the impedance of the leakage current path is sufficiently large, and when lf+f2 is small, switching can be performed. The control circuit 18 automatically performs control to switch the Ck of the impedance element group 11 to the smallest capacitance by the circuit 12.

Therefore, according to this embodiment, even if a situation occurs in which the operator, patient, etc. comes into contact with the exposed metal part of the scope, leakage current will not flow from the endoscope 3 through the operator, etc. can be prevented.

Further, according to the present embodiment, the tip electrode of the processing tool 7 and the exposed metal end of the endoscope 3 contact each other, so that almost no Qs-
If Qo, Vo in alarm area H2 shown in FIG.
/ (Qs −1). At this time, the control circuit 18 immediately detects that it is impossible to set the impedance switching condition, and sends a detection signal to that effect to the alarm 20. Therefore, the alarm 20 can issue an abnormality alarm to notify that the tip electrode of the processing tool 7 is in contact with the exposed metal end of the endoscope 3.

In addition, when the abnormal exposed metal part of the endoscopic scope 3 comes into contact with the living tissue of the subject and almost becomes Qo-0, Vo / (Vs 1) in the alarm area H shown in FIG. It will be shown. In this case as well, the control circuit 18 immediately detects that it is impossible to set the impedance switching condition, and sends a detection means to that effect to the alarm. Therefore, the alarm 19 can notify the patient that there is an abnormality and that the living tissue of the subject is in contact with the abnormally exposed metal end of the endoscope 3.

[Effects of the Invention] As explained above, the high-frequency ablation power supply device for an endoscope to which the present invention is applied has an S pole and a P pole depending on the respective detection conditions of the ablation power supply terminal voltage and the scope-to-ground potential. Since the configuration automatically changes the matching impedance inserted between the endoscope and the endoscope, leakage current from the endoscope can be
We were able to prevent the leakage to the subjects as much as possible.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram schematically showing a high-frequency ablation power supply device for an endoscope according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an outline of a high-frequency ablation power supply device for an endoscope according to an embodiment of the present invention. 3, 4, and 5 are equivalent circuit diagrams for each state to explain the operating principle of an embodiment of the present invention. FIG. 6 is a block diagram showing the state in which the present invention is used in combination. An equivalent circuit diagram showing an example of the impedance between the A and P poles in one embodiment, Fig. 7 is a graph showing the matching impedance and its respective defense areas and alarm areas, Fig. 8 is the capacitance setting situation of the matching impedance FIG. 9 is a diagram schematically showing a conventional S code system. 1... High frequency ablation power supply device 2... P pole 3... Endoscope scope 4... S code 5... A pole
6...A code 7...Processing tool
8... Ground plate 9... P code
10... S pole 11... Impedance element group 12... Switching circuit 13.14... Voltage detection circuit 15.16... Absolute value circuit 17... Division circuit 18
...Control circuit 19.20...Alarm agent jrJ! l! To: Miyoshi f dumb man Figure 2 Figure 3 ■ Figure 5

Claims (2)

[Claims] (1) A high-frequency ablation power supply device for an endoscope that has a function of preventing high-frequency current from flowing to an unintended location via an endoscope, which impedance switching means that can variously change the magnitude of the impedance inserted between them; potential monitoring means that monitors the ablation power supply terminal voltage and scope ground potential; and a detection signal from the potential monitoring means according to the ablation power supply terminal voltage. and condition setting means for setting an impedance insertion condition under which scope leakage current is reduced based on a detection signal corresponding to the scope-to-ground potential, and switching control of the impedance switching means according to the impedance insertion condition by the condition setting means. A high-frequency ablation power supply device for an endoscope, comprising: an ablation environment control means for controlling an ablation environment. (2) The ablation environment control means is provided with one or more abnormality notification means capable of issuing an abnormality notification such as an alarm according to the impossible state when the impedance switching condition cannot be set by the condition setting means. The high-frequency ablation power supply device for an endoscope according to claim 1, characterized in that: