JPH0313897B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cautery hemostasis device equipped with means for detecting deterioration of a heating element.

[Prior art] In recent years, by inserting an elongated insertion section,
BACKGROUND ART Endoscopes, which are capable of diagnosing or performing therapeutic treatments deep within body cavities without requiring incisions from the body wall, have become widely used.

In addition to the observation means, the above-mentioned endoscope is generally provided with a hollow channel through which a treatment instrument can be inserted, and various therapeutic procedures can be performed with a treatment instrument suitable for the therapeutic operation inserted through this channel. It's becoming like that.

By the way, there is a laser coagulation device that coagulates by irradiating a laser beam as a means to stop bleeding when removing a tumor in a body cavity, etc., but currently it is expensive, requires skill, and is dangerous. big.

For this reason, a device has been developed that uses a heating probe that can be inserted into the channel and energizes a heating coil provided at the tip of the heating probe to coagulate the pressed bleeding site.

However, because the responsiveness of the temperature rise and fall during solidification is low, the amount of heat transferred to the surrounding tissue increases during the time it takes to solidify or the time it takes to cool down after solidification. However, it had the disadvantage of causing necrosis of surrounding tissue other than the target area.

For this reason, as disclosed in Japanese Patent Application Laid-Open No. 58-69556, an ablation method using a heating element with good heating and cooling response in a thermal ablation probe (heater probe) that can be passed through the channel. There is a hemostatic device.

The above conventional example uses a Zener diode or an electron avalanche diode as a heat generating element, and uses one with a small heat capacity (that is, a small volume and mass), so the power supplied to the heat generating element is controlled on and off. It is a convenient device because it has good thermal response during heating and cooling, has almost no drawback of causing necrosis of surrounding tissue, and can stop bleeding only at the desired site.

[Problems to be Solved by the Invention] However, in order to improve the thermal response of the above heating element, the amount of electricity consumed per unit time is very large compared to an element with a small heat capacity, and the temperature The amount of increase was also very large, and there was a problem that deterioration of characteristics was unavoidable when used repeatedly under severe conditions that far exceeded the maximum rating.

Therefore, when used repeatedly, the heat generation amount changes due to deterioration of the characteristics of the heating element, and when trying to treat the target area with a heat generation amount depending on the target area, the actual heat generation amount will deviate from the set value. , there is a drawback that appropriate treatment cannot be performed. Further, as the deterioration progresses, there is a risk that the device will break during use, causing reliability problems such as having to interrupt treatment.

[Object of the Invention] The present invention has been made in view of these circumstances, and it is possible to detect whether or not the heating element is within the permissible range, so that cauterization and hemostasis can be performed in an appropriate state at all times, and the above-mentioned fever can be stopped. A small constant current supply means for detecting whether the element is within the allowable range is provided separately from the heating current supply means, and the connection to the heating element can be selected, and the characteristics of the heating element can be adjusted independently of heating control. It is an object of the present invention to provide a cautery hemostasis device in which deterioration can be identified.

[Means and effects for solving the problem] In order to achieve the above object, the cauterizing hemostatic device according to the present invention is a cauterizing hemostatic device for heating a heater probe containing a heating element at the tip to perform therapeutic treatments such as hemostasis. , whether the heating current supply means for heating the heating element, the means for supplying a minute constant current to the heating element, and the voltage across the heating element in a state where the minute constant current is supplied are within an allowable range. A characteristic detecting means comprising a comparison circuit for detecting whether or not the heating current is supplied, and a switching means for selectively connecting the heating current supplying means and the minute current supplying means to the heating element are provided, and the switching means is switched to select the minute current supplying means as the heating element. By connecting, it becomes possible to detect deterioration of characteristics, short circuit, disconnection, etc. of the heat generating element.

[Embodiment] FIGS. 1 to 3 relate to an embodiment of the present invention, in which FIG. 1 shows the configuration of the main part of the embodiment, FIG. 2 shows the external appearance of the embodiment, and FIG. The figure shows a specific circuit configuration of a probe drive circuit in one embodiment.

As shown in FIG. 2, one embodiment of the cautery hemostasis device 1
The power supply box 3 has an operation panel 2 on its sloped front surface, and connectors 5A and 5A are mounted on connector receivers 4A and 4B at the lower front of the power supply box 3, respectively.
An elongated heater probe 5 that can be detachably attached to a connector 5B, and a connector 7 that can be detachably attached to a connector receiver 6A provided at the lower front of the power supply box 3.
It consists of a foot switch 7 provided with A, a water supply tank 8 attached to the side, and a probe drive circuit 9 shown in FIG. 1 provided inside the power supply box 3.

The heater probe 5 is inserted into the probe section 10 in order to energize the heating element housed in the distal end section 11 through a flexible probe section 10 with a small diameter that can be inserted into the hollow channel of an endoscope (not shown). A coaxial cable is inserted through the pipe, and a water supply channel is provided for supplying cleaning water. Then, the electric connector 5A and the water supply connector 5B on the proximal side of the heater probe 5 are attached to the connector receivers 4A and 4B of the power supply box 3, and the foot switch 7
With the connector 7A also attached to the connector receiver 6A of the power supply box 3, by pressing the water supply (cleaning) switch side of the foot switch 7, the cleaning liquid in the water supply tank 8 is supplied through the water supply channel, and the water is supplied to the heater probe. By spraying water from the nozzle of the distal end 11 of 5 towards the affected area for cleaning, or by pressing the heating switch side of the foot switch 7, the heating element is heated via the coaxial cable and the distal end 11 is pressed against it. It is now possible to perform therapeutic procedures such as stopping bleeding at the site.

Incidentally, the jet amount of the washing water and the heating amount of the heating element can be selected and set according to the affected area using setting buttons 2a and 2b provided on the panel 2.

In addition, since the power supply box 3 handles the electrical system and the water supply system, an intermediate chassis is provided at the position shown by the broken line A in the power supply box 3 in FIG. In addition to ensuring safety by separating the water pump and housing it in a waterproof frame, the manufacturing process is also easy, as each system can be worked on separately and then assembled to create a finished product. It is made so that it can be done.

By the way, the probe drive circuit 9 in the first embodiment
The configuration of the main parts is shown in Figure 1.

The probe drive circuit 9 includes a drive constant current circuit 12
and a Zener diode 1 as a heating element to which a constant current is supplied by the driving constant current circuit 12.
3, when switched by the switch 14, a minute constant current is supplied from the minute constant current circuit 15 to the Zener diode 13, and the voltage on the cathode side, for example, of the Zener diode 13 in this state is taken in, and a predetermined voltage is generated. Comparison circuit 1 to compare with reference voltage
6, and a control circuit that takes in the discrimination output of the characteristic detection circuit 17 and maintains the same operating state or operates an alarm circuit 18 to warn of deterioration depending on the discrimination result. 19, a calorific value detection circuit 21 for detecting the calorific value displayed on the LED panel 20, and the like.

By the way, in addition to the control function related to determining the deterioration of the Zener diode 13, the control circuit 18 also controls the setting button 2 of the panel 2 described above.
In accordance with the operation contents of a and 2b, the responding LED panel 20 is turned on or off, and the time constant parameter of the heat generation amount detection circuit 21 is set and controlled in accordance with the operation contents.

The Zener diode 13 used is, for example, of a type with a Zener voltage V ₂ of approximately 20 [V] and a maximum rating of 5 [W]. The anode of this Zener diode 13 is the negative feeding end -V _B (V _B = 15
Connected to [V]. In use, the cathode of the Zener diode 13 is connected to the drive constant current circuit 12 side by the switch 14, and the cathode is connected to the constant voltage IC 12 of the drive constant current circuit 12.
It is connected to the emitter of the control transistor 12b controlled by the resistor 12r1 via the resistor _12r1 .

On the other hand, before and after use, the Zener diode 13 (its cathode) is connected to the characteristic detection circuit 17 side by the switch 14, and a constant current of about 10 [mA] is applied from the minute constant current circuit 15. The cathode voltage of the Zener diode 13 (voltage relative to the negative feed end potential -15 [V]) is the voltage of the comparator 1.
The comparator 16b detects whether the voltage is, for example, 18 [V] or higher, and the comparator 16b detects, for example, whether the voltage is within 25 [V].

When the Zener diode 13 is within the allowable range, the outputs of both comparators 16a and 16b are both high level, the light emitting diode 17Cd is off, and the phototransistor 17Cp forming a photocoupler with the light emitting diode 17Cd is off. The potential of this collector is held at a high level. On the other hand, when the cathode voltage of the Zener diode 13 shifts to the lower or higher side and becomes out of the allowable range, one of the outputs of the comparators 16a and 16b becomes low level, and the light emitting diode 17Cd
lights up, and the collector of phototransistor 17Cp becomes low level. The low level potential of this collector is taken in from the terminal _C6 of the control circuit 19, and the alarm circuit 18 is designed to warn that the Zener diode 13 should be replaced.

A specific circuit configuration of the probe drive circuit 9 is shown in FIG.

As mentioned above, the probe drive circuit 9 includes the drive constant current circuit 12, the Zener diode 13 as a heating element to which a constant current is supplied by the drive constant current circuit 12, and the function of the Zener diode 13 to prevent deterioration of the characteristics of the Zener diode 13. For detection, a minute constant current circuit 15 switches a switch 14 with a relay 23 to flow a minute constant current (for example, 10 mA) to the Zener diode 13 side, and when this constant current is flowing, the cathode potential of the Zener diode 13 is A characteristic detection circuit 17 detects whether the characteristics are deteriorated or short-circuited or disconnected within a specified range, an alarm circuit 18 operates in an abnormal state, and detects whether the total heat generation amount has reached a set value. In addition to the heat generation amount detection circuit 21 for controlling the temperature of the Zener diode 13, a heat generation control circuit 25 for controlling the heat generation temperature of the Zener diode 13 by utilizing the temperature dependence of the Zener voltage _VZ , and a heating current for the Zener diode 13 are provided. A clock circuit 2 constitutes a current interrupting means capable of measuring time from the time when the current is passed, and using the output signal to switch the switch 14 of the relay 23 to forcibly stop the output current.
7, and each of these circuits is controlled by a control circuit 19 formed by a one-chip microcomputer.

The drive constant current circuit 12 uses a constant voltage IC (for example, μA723) 12a, and the control output terminal of this IC 12a
A voltage of V _put is applied to the base to control the collector-emitter current of the control transistor 12b,
The current value can be regulated to a predetermined value, for example, 540 mA or 400 mA, depending on whether the heater probe 5 has a large diameter or a small diameter. For example, when a large diameter heater probe 5 is attached, a resistor ra is connected to the connector 5A in this case, and this resistor ra is connected to the connector 5A.
This allows the current flowing through the Zener diode 13 to be larger than that in the case of a small diameter one in which the resistor ra is not provided. That is, this resistance ra
As a result, the combined resistance value on the emitter side of the control transistor 12b in the drive constant current circuit 12 becomes the parallel connection value of the resistor _12r1 and the resistor ra, and becomes smaller, and the limiting current value is increased.

In addition, by adjusting this value using the variable resistor _rb provided in the connector 5A, it is possible to set the current value to an appropriate value even if there is some variation in the Zener voltage _Vz of the Zener diode. There is.

The constant voltage IC _12a is provided with a current limiting terminal C _LIM , and a phototransistor 12C _P1 forming a photocoupler is connected to this terminal C _LIM , and a light emitting diode (LED )12C When _d1 emits light, it becomes conductive (turned on) and the output current limit is released. The light emitting diode 12C _d1 constituting this photocoupler has its anode connected to the (positive) power supply terminal V _A (+5V) via a resistor, and its cathode connected to the control circuit 19 via a buffer B ₁ formed by an open collector inverter. The LED 12C _d1 emits light when _{the terminal C 1 becomes} high level. Also, when this terminal C ₁ becomes high level, the LED 15C _d connected to the buffer B ₁ emits light and the phototransistor 15C _P provided in the minute constant current circuit 15 turns on, stopping this minute constant current function. It is designed to let you do so.

Further, the drive constant current circuit 12 includes a phototransistor 12C _P2 connected to the frequency correction terminal F _COM .
When turned on, the output current of the drive constant current circuit 12 is cut off. The LED 12C _d2 paired with the phototransistor 12C _P2 is controlled by the output level of the terminal C ₂ of the control circuit 19.

By the way, in the control circuit 19, when the connector 5A is connected to the connector receiver 4A, the terminal _C4 changes from a high level to a low level through the electrically connected terminals 5a and 5b of the connector 5A, and the heater probe 5 changes from a high level to a low level. The control circuit 19 can detect that the connector 5A is attached. However, this terminal
When C ₄ becomes low level, terminal C ₁ is set to high level, LED 15C _d is turned on, phototransistor 15C _P is turned on, and minute constant current circuit 15 is operated. In this case, the terminal _C5 in the control circuit 19 is at low level,
(Nand) Transistor Q ₁ via gate G ₁ is in an off state, no current flows through solenoid 23s of relay 23, and in this state, switch 14 has conduction between contacts 14a and 14c as shown by the solid line. Therefore, the Zener diode 1 is connected from the minute constant current circuit 15 through the connector 5A of the heater probe 5.
A minute constant current of, for example, 10 mA will flow through 3. The minute constant current circuit 15 has a load resistance 15r ₁ by an operational amplifier 15a.
The voltage of _15r2 is fed back to the resistor 15
It is controlled so that a predetermined current (10mA) flows through _r1 .

When the minute constant current flows, the potential of the cathode of the Zener diode 13 is detected by the characteristic detection circuit 17.

That is, one comparator 16 in the comparison circuit 16
The inverting input terminal of a connects +V _B and -V _B to resistors 16r ₁ and 16
It is set so that a predetermined voltage divided by r ₂ (+18V for -V _B , +3V for zero level) V _L is applied, and the non-inverting input terminal is the cathode voltage of the Zener diode 13 mentioned above. is applied. In the other comparator 16b, the non-inverting input terminals +V _B , -V _B
A _{predetermined} voltage ( _{-V B}
+25V) _VH is applied to the inverting input terminal, and the above cathode voltage is applied to the inverting input terminal.

The output terminals of both comparators 16a and 16b are LEDs.
It is connected to the power supply end +V _B via 17Cd and a resistor. (Incidentally, the output terminals of both comparators 16a and 16b may not be connected directly, but may be connected through a resistor. Also, there is an input voltage difference between both input terminals of each comparator 16a, 16b. It is also possible to connect a (Zenner) diode in which the forward and reverse directions are connected in parallel to protect the comparators 16a and 16b when is too large (in the case of a short circuit, etc.).It can also be used in other circuit parts. ) Therefore, if the Zener diode 13 has a regular Zener voltage V _Z in a constant current state of 10 [mA] as specified in the product standard, both comparators 1
The outputs of 6a and 16b become high level, and the LED
17Cd does not emit light. However, if the Zener voltage deviates from the normal Zener voltage V _Z due to deterioration of characteristics during use, the output of one of the comparators 16a and 16b becomes low level and the LED 17Cd emits light. When this LED 17Cd emits light, the paired phototransistor 17Cp is turned on and the terminal _C3 changes from high level to low level. This terminal C ₃
When becomes low level, the control circuit 19
detects an abnormality in the characteristics and activates the alarm circuit 18 to warn that the characteristics of the Zener diode 13 are not within the allowable range and should be replaced. Furthermore, even if the Zener diode 13 that has been replaced is not due to characteristic deterioration but is significantly deviated from the specified value, it can be known from the operation of the alarm circuit 18 that the Zener diode 13 is not appropriate.

By the way, the collector of the control transistor 12b is connected to the heating power supply terminal V _B (+15V) via a resistor _25r1 (in the heat generation control circuit 25), and the voltage corresponding to the voltage drop due to this resistor _25r1 is connected to the operational amplifier. It is applied to one input terminal of the (operational amplifier) 25a, and the other input terminal is held at the reference potential _VS. This operational amplifier 25a amplifies the voltage between both input terminals (between them) by a factor of 3.9, for example, and this output is applied to the input terminal of the multiplexer 26a of the heat generation detection circuit 26, and the resistor 25r ₂ and the transistor 2
It flows through the emitter-collector of 5b and the resistor _25r3 to the negative power supply end _-VB side.

This current changes the potential at the connection point between the resistor _25r3 and the collector of the transistor 25b, and this potential changes the voltage at the (non-inverting) control input terminal _IN of the constant voltage IC 12a via the resistor _25r4 . The voltage at the control input terminal I _N changes the output level at the control output terminal V _put to control the heating current. The feedback loop in this case is set to provide positive feedback. For example, when the current flowing through the resistor _25r1 increases, the potential at the inverting input terminal decreases, so the output level of the operational amplifier 25a increases, the potential at the collector of the transistor 25b also increases, and the potential at the control input terminal _IN of the constant voltage IC 12a increases. As a result, the output level of the control output terminal _Vput also increases, and the heating current flowing through the control transistor 12b increases. In the opposite case, the heating current is reduced.

Note that the control input terminal I _N is connected to the reference voltage terminal V _REF via a resistor 12r ₂ .

On the other hand, the heat generation amount detection circuit 21 detects a series resistance group 21r at the output end by a digital signal outputted from the terminal (group) _C6 of the control circuit 19.
A combination of (four shown in the figure) to be short-circuited is selected, and its series combined resistance value can be selected. This combined resistance and the operational amplifier 21b
The integration time constant of the integration circuit can be selected by the capacitance of a capacitor 21C connected between the inverting input terminal and the output terminal of the integration circuit.

Both ends of the capacitor 21C of the operational amplifier 21b that constitute the above integration circuit are connected to the photo FET 21C _P1 , and when the LED 21C _d1 is emitting light, both ends of the capacitor 21C are short-circuited, and the output of the operational amplifier 21b is at a level lower than the non-inverting input terminal of the operational amplifier 21d. Retained.

When the terminal _C2 of the control circuit 19 is set to high level, the short circuit of the capacitor 21C is released and the integration operation is started. When the output of the operational amplifier 21b exceeds the reference level at the next stage operational amplifier 21d, the operational amplifier 21d The output becomes low level, and LED21C _d2 emits light. However, when this LED21C _d2 emits light,
The paired phototransistor 21C _P2 turns on,
Terminal _C7 becomes low level via buffer _B4 .
When this terminal C ₇ becomes low level, the control circuit 19 sets the terminal C ₂ to low level, for example.
The LED 12C _d2 is made to emit light, the phototransistor 12C _P2 is turned on, and the current output from the drive constant current circuit 12 to the load side is cut off.

By the way, switch 1 in the relay 23
When the contacts 14a and 14c of 4 are made conductive and a minute constant current is passed, if no short circuit or characteristic deterioration is detected, when the foot switch 7 is pressed, the terminal
_C8 outputs a trigger signal that changes from high level to low level. This signal is transmitted to a timer IC (for example,
Applied to the trigger input terminal T _RIG of NE555) 27a,
From the rising edge of this trigger signal, the timer IC2
7a outputs a high level signal from the output terminal OUT for a predetermined time (for example, 10 seconds) set by the resistor 27r and capacitor 27c, and this output signal is applied to the gate _G1 and also to the clock terminal CK of the flip-flop 28. is applied to The flip-flop 28 is configured to output a low level signal, which is the output stop signal level, from the output terminal Q to the terminal _C7 of the control circuit 19 via the buffer _B5 at the falling edge of the clock signal. In other words, since this output stop means is provided, even if an accident occurs such as when the heater probe is disconnected during use, the output will stop after a predetermined period of time has elapsed.
The flip-flop 28 is activated by the output of the clock circuit 27.
Since _the terminal _C7 is forcibly set to low level through will not be output. Furthermore, even if the control circuit 19 goes out of control due to external noise, etc., the output of the timer IC 27a becomes low level after a predetermined period of time, so the transistor Q ₁ via the gate G ₁ is turned off, and the relay 23 is turned off. Switch contacts 14a and 14b are turned off and no power supply line is formed.

Therefore, the clock circuit 27 using the timer IC 27a, the flip-flop 28, the gate _G1, etc., which are operated by the output of the clock circuit 27, can prevent the relay from running even if the control circuit 19 goes out of control. Since the switch contacts 14a and 14b in the middle of the power supply line 23 are turned off, measures are taken to prevent current from continuing to flow through the Zener diode 13.

Furthermore, when the terminal _C7 goes to low level, if the control circuit 19 is functioning normally, it turns off the switch contacts 14a and 14b of the relay 23, and also sets the terminal _C2 to low level to turn off the constant voltage IC.
This will activate the output current cutoff function of 12a.

Note that the heat generation control circuit 25 controls the heat generation temperature of the Zener diode 13 in the following manner.

That is, the Zener diode 1 as a heating element
3, the Zener voltage V _Z exhibits a slight positive temperature dependence, and when heat is generated due to this temperature dependence, the amount of temperature rise changes depending on the heat dissipation state at the tip 11 of the probe 5. do. This temperature rise becomes the current change, and this current change is the resistance 25r ₁
The voltage drop amount is detected by the operational amplifier 25a, and the current amount is controlled by a positive feedback loop including the operational amplifier 25a. In other words, when the temperature rise becomes large, the current is reduced to prevent the temperature at the tip 11 from rising too much, and when the heat dissipation is large, the amount of heat generated is increased to maintain the temperature at a temperature suitable for hemostasis. It's like this.

The operation of one embodiment configured in this manner will be described below.

When the connector 5A of the heater probe 5 is connected to the connector receiver 4A of the power supply box 3, the terminal 5
Terminals of the control circuit 19 via a and 5b
_C4 becomes low level, and it is detected that the connector 5A is connected. When this connection is detected, the control circuit 19 sets the terminal C ₁ to a low level, turns off the LED 15C _d , turns off the phototransistor 15C _P , and turns off the micro constant current circuit 1.
5 is activated to supply a minute current to the Zener diode 13 side via terminal 4H _P. In this case, the terminal
When _C5 becomes low level, the transistor
Since _Q1 is turned off, the switch contacts 14a and 14c of the relay 23 are turned on. Therefore, both the comparators 16a and 16b detect whether the cathode potential of the Zener diode 13 is within the allowable level range and whether or not the heater probe 5 side is short-circuited. Ru.
(Zener voltage V _Z of the Zener diode 13 above
If the Zener diode 13 at the time of this detection is short-circuited, it will be detected by one comparator 16a, and if there is a disconnection, it will be detected by the other comparator 16b. In addition to detecting characteristics, the presence or absence of short circuits and disconnections is also detected. ) The minute constant current circuit 15, when the load is released,
The voltage between the terminals 4Hp and -4Hp to which the Zener diode 13 is connected is almost 30 [V], and the emitter terminal of the turned-on phototransistor 15Cp is almost 15V (15, IV). resistance 15
r ₁ , 15r ₂ etc. are set. Therefore, the above terminal
If the voltage of 4Hp is V _E and the load resistance between both terminals 4Hp and -4Hp is R, then (30-V _E )/R ₁₅ r ₁ =
V _E /R + (V _E -15) / R ₁₅ r ₂ . here
R ₁₅ r ₁ and R ₁₅ r ₂ are the resistance values of the resistors 15r ₁ and 15r ₂ , respectively. Therefore, when the Zener diode 13 is connected as the load, the Zener voltage V _Z is 9,
9 to 10, 7 [mA], and its characteristics can be investigated under the same conditions as the manufacturer's product specifications.

When the Zener diode 13 emits light, the Zener voltage V _Z appears to increase.

In reality, the temperature reaches its highest immediately after a large current is applied due to heating. Therefore, when measuring after use, it is necessary to take into account the rise in Zener voltage V _Z due to this temperature rise.

If the room temperature is 25°C, the maximum temperature of the Zener tip during heating is 225°C, so the temperature rise up to this point is 200°C. The temperature coefficient of the Zener voltage V _Z of the Zener diode 13 used is 15 mV/℃
Therefore, the increase in Zener voltage due to a temperature increase of 200℃ is 15mV x 200℃ = 3V Therefore, the threshold can be set by adding 3V to the upper limit of the normal selection range. Actually, since there is an error in the operational amplifier 15a, 25V is set as the upper limit threshold with -4HP as the reference. Regarding the lower threshold, since the temperature coefficient of the Zener voltage V _Z is positive, the Zener voltage of the Zener diode 13 incorporated in the tip is
You can set it to the lower limit of _VZ , but the lower limit should be 18V, including variations in the main unit. Therefore, a signal that is determined to be normal is output only to the probe 5 within the range of 18 to 25 V, including the temperature rise of the Zener voltage V _Z due to heating or the flow of the detection current. If there is no characteristic deterioration etc., when the foot switch 7 is pressed, the terminal _C5 is set to high level,
When the constant voltage IC 12a operates, the relay 23
The switch contacts 14a and 14b are turned on to form a power supply line, so that a heating current flows to the Zener diode 13 side. Also, the above terminal
C ₅ is set to high level and terminal C ₈ is for example several tens of mS
becomes low level for a period of . This time may be determined by using a built-in clock means of the control circuit 19, or by using a timer IC or the like. or,
At the rising edge when terminal _C8 changes from low level to high level, the timer IC 27a of the clock circuit 27
The output of is at high level for a predetermined period of time, and this output is applied to the other input terminal of gate _G1 .

Therefore, when the output of the gate _G1 , that is, the base potential of the transistor _Q1 is at a low level, the transistor _Q1 is turned on, operating the relay 23 and turning on the switch contacts 14a and 14b, forming a power supply line. do it like this.

After allowing for the delay operation time (several tens of milliseconds) of the relay 23 mentioned above (this time is also
This can be achieved using the built-in clock or for a timer.
It may also be formed using an IC or the like. ) The control circuit 19 sets the terminal C ₂ to high level, turns off the LED 12C _d2 , turns off the phototransistor 12C _P2 so that current flows to the Zener diode 13 side, turns off the LED 21C _d1 , and turns off the operational amplifier 21b. Activate the integration circuit consisting of etc.

The current flowing through the Zener diode 13 becomes a large current (for example, about 1.5 A) with the current limit released due to the positive feedback loop using the operational amplifier 25d, and is rapidly heated. After heating, a timer circuit (not shown) etc. When the elapsed time has elapsed, the elapsed signal is input to the control circuit 19, and the control circuit 19 sets the terminal _C1 to a low level. When this terminal C ₁ becomes low level, the LED 12C _d1 is turned off and the current flows through the Zener diode 13 in the current limit state.

Since the Zener voltage V _Z of the Zener diode 13 has temperature dependence, when the temperature rise increases, the current decreases, and this decrease is detected by the heat generation control circuit 25, and a positive feedback loop controls the temperature rise. Even if the state of heat dissipation at the distal end portion 11 changes, the temperature is maintained at a temperature suitable for hemostasis.

The current flowing through the Zener diode 13 is:
It is integrated by the integrating circuit via the multiplexer 21a, and when the preset amount of heat is reached, the output of the operational amplifier 21d becomes low level, and the LED 21C _d2
lights up, phototransistor 21C _P2 turns on,
Terminal _C7 becomes low level and an interrupt is generated.

Then, the control circuit 19 connects the terminals C ₂ and C ₅
Set the signal level to low.

When the terminal C ₂ is set low, the LED 12C _d2 emits light, the phototransistor 12C _P2 is turned on, and the heating current is not output from the driving constant current circuit 12. Furthermore, when the terminal _C5 is set to a low level, one input terminal of the gate _G1 is set to a low level, so the transistor _Q1 is turned off, and the relay 23 turns off the switch contacts 14a and 14b to supply power. Lines are prevented from forming. In this way, heating is reliably stopped. Note that the output of the timer IC 27a becomes low level after a predetermined time.

The above operation occurs when the control circuit 19 works normally, and when the heater probe 5 is disconnected and the current no longer flows, or the control circuit 19 goes out of control due to external noise etc., it is terminated from the heat generation detection circuit 21. It may happen that the signal for the Even in this case, after a predetermined period of time has elapsed, the output of the timer IC 27a becomes low level, and accordingly, the transistor _Q1 via the gate _G1 is turned off in the same manner as described above, and the relay 23 switch opens the contacts 14a and 14b. The heating current is cut off. Also, the output of the flip-flop 28 goes high at the falling edge of the low level, causing the terminal _C7 to go low and causing an interrupt as described above. Therefore, even if the control circuit 19 or the like malfunctions, the timing means ensures that the heating current will not be output after a predetermined period of time, so the hemostasis site will not continue to be abnormally heated, making it safe. .

Note that the means for forcibly cutting off the heating current by the timekeeping means is not limited to the relay 23, and may be formed using a semiconductor such as a thyristor.

Further, when detecting the characteristics (including short circuits, disconnections, etc.) of the Zener diode 13 using the characteristic detection circuit 17, it is desirable to operate the circuit 17 before and after the actual cauterization and hemostasis treatment. In this case, the operating period does not need to be long, and in the first embodiment described above, it can be freely controlled by the period in which the phototransistor 15Cp is turned on, but it is not limited to this embodiment. Further, even during use, the characteristic detection circuit 17 can be operated during a period in which heating for cauterization and hemostasis is stopped.

Note that the comparison circuit 1 provided in the characteristic detection circuit 17
In step 6, a comparator is provided that is set at a level different from the set level of the comparators 16a and 16b, so that a warning that a failure has occurred in the heating element can be issued if the level deviates significantly from the allowable range (i.e., short circuit, disconnection, etc.). You can also do that.

[Effects of the Invention] As explained above, according to the present invention, it is possible to detect whether or not the heating element is within the permissible range, so that hemostasis can be performed by cautery in an appropriate state at all times, and the heating element is within the permissible range. A minute constant current supply means is provided separately from the heating current supply means to detect whether or not the heating current is present, so that connection to the heating element can be selected, and characteristic deterioration of the heating element can be identified independently of heating control. effective.

[Brief explanation of drawings]

1 to 3 relate to one embodiment of the present invention, FIG. 1 is a block diagram showing the main parts of a probe drive circuit in one embodiment, FIG. 2 is a perspective view showing the external appearance of one embodiment, FIG. 3 is a circuit diagram showing a specific circuit configuration of a probe drive circuit according to one embodiment. 1... Cautery hemostatic device, 2... Panel, 3... Power supply box, 5... Heater probe, 5A... Connector, 7
...Foot switch, 9...Probe drive circuit, 12
... Drive constant current circuit, 13... Zener diode,
14...Switch, 15...Minute constant current circuit, 16...
Comparison circuit, 17... Characteristic detection circuit, 18... Alarm circuit, 19... Control circuit, 21... Calorific value detection circuit.

Claims (1)

[Claims] 1. A cautery hemostasis device for performing therapeutic treatment such as hemostasis by heating a heater probe that houses a heating element at its tip, comprising: heating current supply means for heating the heating element; and supplying a minute constant current to the heating element. characteristic detecting means comprising a comparison circuit for determining whether the voltage across the heating element is within a permissible range when a constant minute current is supplied; and the heating current supplying means and the minute current supplying means. A cautery and hemostasis device comprising a switching means selectively connected to the heating element.