JP2007105459A - Sensor/wire assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor/wire assembly, easy to use and capable of reducing the general cost of operation. <P>SOLUTION: This sensor/wire assembly for measuring a physiologic change includes: a sensor element for measuring a physiologic change in a living body and generating a sensor signal corresponding to the change; and a guide wire having the sensor element at the tip and adaptable for insertion in the living body to locate the sensor element in the living body. The assembly further includes a sensor signal adaptation circuit as an integrated part, and in the adaption circuit, the sensor signal is supplied, and an output signal is automatically generated in a standard format in correlation to the sensor signal. Thus, the measured physiologic change can be read out by an external physiologic monitor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is directed to a sensor wire assembly for measuring physiological changes in vivo in light of the preamble of the independent claim of the present invention.

  In many medical procedures, medical workers need to monitor various physiological conditions within a patient's body cavity. These physiological conditions are typical physiological characteristics such as blood pressure, body temperature, fluid flow rate, etc. and provide doctors and medical technicians with important information about the condition of the patient. The means for monitoring these types of parameters must, of course, be safe, accurate and reliable.

  One widely used device for monitoring such conditions is a blood pressure transducer. The blood pressure transducer detects the height of the patient's blood pressure and converts it into a rendered electrical signal. Next, this electric signal is supplied to a living body display monitor, and the blood pressure level of the patient is displayed, recorded or monitored by the monitor.

  Conventionally, a blood pressure transducer consists of a pressure responsive diaphragm mechanically coupled to a piezoresistive element connected in a Wheatstone bridge type circuit arrangement. When the diaphragm is placed in a fluid flowing through a body cavity (such as in an arterial or venous system), the pressure that causes the diaphragm to deflect stretches the resistive elements (depending on their orientation) (or Shrink). Thereby, the resistance of the element changes in proportion to the applied pressure according to a known principle. As a result, the magnitude of the applied pressure can be detected by monitoring the excitation power signal (usually in the form of voltage) applied to the Wheatstone bridge circuit and the output signal of the bridge. The magnitude of the signal corresponds to the amount by which the resistance of the bridge has changed according to Ohm's law.

  Typically, the Wheatstone bridge portion of the transducer sensor is connected by an electrical cable to a transducer amplifier circuit that includes a biological signal monitor. This amplifier circuit provides an excitation power signal to the Wheatstone bridge and simultaneously monitors the output signal of the bridge. The excitation voltage signal is typically in the form of a voltage, depending on the monitor type and manufacturer, magnitude and format, i.e. time dependent (sine, square and pulse) and non-time dependent. Dependency (DC) is changed.

  Based on the principle of operation of conventional Wheatstone bridge transducers, transducer amplification circuits in most patient monitors require a sensor output signal having a magnitude proportional to the magnitude of the excitation power signal and the sensed pressure. Designed to be Because different monitors provide excitation voltage signals with different magnitudes and / or frequencies, a number of standard proportionality constants have been developed. With these standard proportionality constants, any sensor can be easily applied to any patient monitor and can follow the proportional standard. Such compatibility provides several advantages. The blood pressure transducer can be used interchangeably with patient monitors from different manufacturers. In this way, the medical technician is not required to select a specific transducer for a specific monitor. In addition, the investment the hospital has made in existing patient monitors can be maintained, thereby reducing costs. As a result, biometric display monitors compliant with these proportional standards have achieved almost full common adoption in the medical environment.

  However, the blood pressure transducer and monitor have been used for some time and the built-in standard is not without its drawbacks. For example, the sensors used in these systems are typically placed outside the patient's body and placed in the fluid that is flowing into the body cavity via a catheter tube filled with fluid. Therefore, the pressure change in the body cavity is indirectly transmitted to the diaphragm by the liquid filled in the catheter tube. For this reason, the accuracy of such systems is reduced due to changes in hydraulic pressure and other inconsistencies associated with the liquid column.

  In response to such problems, small sensors using advanced semiconductor technology have been developed. These types of transducer sensors are very precise and inexpensive and still use the known Wheatstone bridge circuit arrangement, which is typically at least partially silicon.・ It is formed directly on the diaphragm. Furthermore, these sensors are small enough that they can actually be attached to the tip of an indwelling guide wire and can be placed directly into a patient's artery, tissue or organ. By eliminating the need for a liquid tube in this way, the hydraulic pressure is directly transmitted to the transducer diaphragm. Because of this, these sensors are often referred to as indwelling or guide wire tip-mounted transducers, and can more accurately measure a patient's blood pressure.

  Unfortunately, however, the electrical structure of these small semiconductor sensors is not always compatible with existing patient monitor transducer amplifiers. For example, the miniature sensors often cannot operate over the full range of excitation signal magnitudes and frequencies found in many patient monitors. Therefore, the small sensor cannot be directly connected to many already used patient monitors. In order to use such an existing monitor, a special interface must be installed between the sensor and the monitor. Since existing monitors are designed to supply only a limited amount of power, such an arrangement requires that a circuit be added to the interface, which has an independent power source. Necessary. Therefore, the use of the novel small sensor often increases the cost and complexity of the entire system.

  In addition, due to the limitations described above, the miniature sensor often has an output signal that is proportional to the sensed pressure, but does not correlate to the excitation signal supplied by the sensor and can be used directly in the physiological monitor. For example, it must be configured so that its sensitivity is different. As mentioned above, this miniature sensor is not compatible with the electrical format required for many commercially available monitors that are already widely used. Thus, the new sensor can only be used for special monitor types, thus requiring the purchase of additional, often extra equipment. This is unacceptable in light of the cost perception prevailing in today's medical environment.

  Patent Document 1 discloses an interface circuit for connecting a sensor to a patient monitor. The interface circuit includes a power supply circuit that receives the excitation power signal generated by the patient circuit and generates unspecified and specified supply voltages for use by electrical components on the interface circuit. Furthermore, the power supply circuit generates a suitable sensor excitation signal. The interface circuit further includes a receiving circuit for receiving a sensor output signal generated by the sensor. A counting circuit then converts the signal into a parameter signal proportional to the physiological condition detected by the sensor and proportional to the excitation electrode signal generated by the patient monitor. The obvious problem of the device described in Patent Document 1 is that a separate additional unit is required in the configuration of the interface circuit in order to connect the sensor to the monitor.

  A similar solution is disclosed in US Pat. This publication relates to a signal conditioner for connecting various sensor devices such as a guide wire attached pressure sensor to a physiological monitor. The signal conditioning device has a processor for controlling a built-in sensor excitation and signal conditioning circuit. The processor also provides a signal representing the processed sensor signal received by the sensor interface of the signal conditioner to an output stage on the signal conditioner. Power for the signal conditioning device processor is provided by an excitation signal received from a physiological monitor that drives the output stage. Further, the temperature compensation current source supplies an adjustment current to at least one of the pair of resistance sensor elements to compensate for a temperature change difference between the pair of resistance sensor elements, thereby invalidating the temperature effect in the resistance sensor elements. To.

  The Medical Instrument Development Association (“AAMI”) defines power requirements for physiological monitoring, and in particular, input / output couplings to sensor wire assemblies are a standard set by the American National Standards Institute (“ANSI”). It was determined that AAMI BP22-1994 (hereinafter referred to as “BP22”) must be followed.

  According to the BP22 standard, the input / output coupler attached to the tip of the five-wire connecting cable has a pair of differential output signal lines. The output signal is driven by an output digital-to-analog converter of a sensor matching circuit (described in more detail below). The differential output signal operates at 5 μV / mmHg, for example. Therefore, an operating range of −150 μV / V to 1650 μV / V represents a detected pressure range of −30 to 330 mmHg. A typical resolution (minimum step) of the differential output signal is 0.2 mmHg.

  The obvious problem with the commercially available prior art interfaces is that they are large, require user input and add to the complexity of the device used in intensive care operating rooms.

  Furthermore, a commercially available interface device requires inspection, calibration, software update, etc., and the back support management of the device increases, and a spare unit used when some of the devices are under inspection. Need to be retained, all of which together increase costs.

US Pat. No. 5,568,815 US Pat. No. 6,585,660

  The present invention has been made in view of the above-described conventional circumstances, and an object thereof is to provide a sensor wire assembly that is easy to use and can reduce the overall cost of operation. .

  The object is achieved by the invention according to the independent claims.

  Therefore, the sensor wire assembly according to the present invention does not require a standard input / output coupler of a physiological monitor, ie directly, ie without the additional interface devices required for the prior art described above. Can be connected.

  A standard input / output coupler means that it is compliant with an established standard, for example BP22, or the relevant part of such a standard.

  Preferred embodiments are described by the dependent claims of the present invention.

  The present invention is based on the insight that commercially available prior art interface devices are too large and sometimes difficult to use.

  In the solution disclosed in accordance with the present invention, the essential circuitry is significantly miniaturized for integration in a socket connector, in a wire connector, or somewhere along the sensor wire assembly. Yes.

  As the present inventor recognizes, the cost expected when manufacturing the assembly as a disposable device can be significantly reduced by using the standard circuit available now, for example, in a signal conditioning unit. This is because the need for maintenance, calibration and software updates required in prior art interface devices is not required for the sensor wire assembly of the present invention.

  Thus, according to the present invention, a sensor signal adaptation circuit can be provided between a pressure sensor built into the indwelling guide wire and a physiological monitor displaying a human-readable output corresponding to the sensed pressure. The adaptation circuit can receive synchronization information from the physiological monitor, for example in the form of an excitation signal, and emits a regulated and standardized output in the form of an analog voltage output signal.

  According to a preferred embodiment, the adaptation circuit excites a pressure sensor built into the guide wire, for example by sensor current / voltage, adjusts the sensed analog sensor input signal, and mathematically A transformation is performed (using a microprocessor) to display the normalized output on the physiological monitor.

  Furthermore, the main advantage of the present invention is that no input by the user is required to use the assembly; instead, the assembly can be connected and used directly at any time, and the sensor signal adaptation The circuit automatically adapts the output to the applied sensor signal.

  The sensor wire assembly according to the present invention is simple to use and can reduce the overall cost of operation.

  In the prior art, it is known to assemble a sensor on a guide wire, position the sensor in a blood vessel of a living body via the guide wire, and detect physical parameters such as blood pressure and body temperature. The sensor includes an element that directly or indirectly detects the parameter. Applicants own many patents that describe various types of sensors for measuring physiological parameters. For example, as described in US Pat. No. 6,615,067, the temperature can be measured by observing the resistance of a conductor having a temperature sensitive resistance. In another exemplary sensor described in US Pat. No. 6,167,763, blood flow exerts pressure on the sensor, which emits a signal representative of the pressure. A signal is applied to the sensor to indicate a measured physiological change and is transmitted to an external physiological monitor and one or more cables or conductors connected to the sensor for transmitting the signal. , Sent along the guide wire, passed through the housing, and sent to an external physiological monitor via the coupling means. Further, the guide wire typically includes a central metal wire (core wire) that supports the sensor and functions as an electrical connector of the sensor (if necessary), and a surrounding tube. Has been. Thus, the guide wire is typically composed of a core wire, a conducting wire and a protective tube.

  FIG. 1 shows an example of a sensor mounting guide wire according to a conventional design applicable to the present invention. The sensor guide wire 101 includes a hollow tube 102, a core wire 103, a first spiral portion 104, a second spiral portion 105, a jacket or sleeve 106, a dome-shaped tip 107, a sensor element or sensor chip 108, And several electric conductors 109. The tube 102 is typically treated to give the sensor guide structure a smooth outer surface with a low coefficient of friction. The proximal end of the first spiral portion 104 is fixed to the distal end of the hollow tube 102, and the distal end of the first spiral portion 104 is fixed to the proximal end of the jacket 106. The proximal end of the second spiral portion 105 is fixed to the distal end of the jacket 106, and the dome-shaped distal end 107 is fixed to the distal end of the second spiral portion 105. At least a part of the core wire 103 is disposed inside the hollow tube 102, whereby the distal end portion of the core wire 103 extends from the hollow tube 102, and the inside of the second spiral portion 105. In. The sensor element 108 is attached to the core wire at a portion where the jacket 106 is provided, and is connected to an external physiological monitor (not shown in FIG. 1) via an electrical lead 109. The sensor element 108 has a film-like pressure-sensitive device (not shown in FIG. 1) that comes into contact with a medium such as blood covering the tip of the sensor guide wire 101 through the opening 110 of the jacket 106. Yes.

  FIG. 2 shows a schematic configuration of a sensor wire assembly for measuring physiological changes in a living body according to the present invention, and FIG. 3 is a block diagram schematically showing a sensor signal adaptation circuit according to the present invention. A diagram is shown.

  As shown in FIGS. 2 and 3, the assembly includes a sensor element that measures the physiological change and generates a sensor signal corresponding to the physiological change, and the sensor element at its tip, preferably near its tip. And a guide wire that can be inserted into a living body in order to position the sensor element in the living body. Furthermore, the assembly has a sensor signal adaptation circuit (FIG. 3) that is an integral part of the assembly, in which the sensor signal is sent to the adaptation circuit, which automatically The output signal is generated in a format such that the measured physiological change can be read out by an external physiological monitor. The sensor signal adaptation circuit includes a programmable sensor adjustment unit and a calibration means supplied with calibration data, recorded and modified, eg, an electrically erasable programmable read only memory (EEPROM). It has a unit, an energy means, and an output amplification unit.

  The programmable sensor adjustment unit is preferably a PGA309 programmable analog sensor adjuster (commercially available from Texas Instruments) specifically designed for bridge sensors.

  Also, the coupling means shown in FIG. 2 couples the assembly to the physiological monitor input / output coupling.

  Further, the assembly includes a connecting cable, which is connected to the guide wire via a wire connector disposed on the connecting cable, and in this configuration, the guide wire Is located at the tip of the assembly. The adaptation circuit is preferably located in the wire coupler, but may be located somewhere along the coupling means or the assembly.

  The sensor wire assembly according to the preferred embodiment of the present invention shown in FIG. 4 has a sensor element 308, which is attached to a guide wire 301. A male connector 313 is provided at the tip. The sensor assembly further includes a sensor signal adaptation circuit 312 that formats the sensor element signal representative of the measured physiological change. The sensor assembly also includes a wire connector in the form of a female connector 314, which is provided at one end of a connecting cable 315. In this particular embodiment, the signal adaptation circuit 312 is located and attached to the female coupler 314. However, the adaptation circuit may be located substantially along the sensor assembly as long as it is integral to the sensor assembly. In use, the sensor assembly is connected through its male connector 313 to a female connector 314 provided at one end of the interface connection cable 315. The male connector 313 and the female connector 314 constitute the wire connector shown in FIG. The other end of the cable is provided with an insertion terminal for connection to a physiological monitor 316, and the physiological monitor 316 can display a value indicating the pressure measured by the sensor element 308.

  In addition, the balloon catheter 311 shown in FIG. 4 is connected to the guide wire 301 after the therapist places the guide wire 301 at an appropriate position in the living body. This is accomplished by removing the guide wire male connector 313 from the female connector 314 of the connection cable 315 and passing the balloon catheter 311 over the guide wire. Once the balloon catheter 311 is properly positioned, the guide wire is reconnected to the interface cable for further measurements.

  The physiological monitor 316 supplies a reference voltage to the sensor assembly via the cable 315. By adapting the signal standard to which the physiological monitor 316 conforms and examining the signal standard presented to the sensor assembly by the reference voltage and the effective value of the physiological parameter measured by the sensor element 308 A circuit 312 processes the signal from the sensor element, and a signal adapted based on the standard required by the monitor is sent back through the cable 315.

  5 and 6 show a wire coupler according to a preferred embodiment of the present invention. In FIG. 5, the coupler is in an assembled state, and in FIG. 6, it is in an unassembled state.

  The wire coupler includes a wire coupler casting that is a body of a female coupler that further includes a circuit casting that includes the programmable sensor adjustment unit (PGA 309), and the calibration unit, for example, an electrically erasable program. A possible read only memory (EEPROM), energy means and the output amplification unit for connecting the adaptation circuit to the connecting cable. The wire coupler is constituted by a guide wire housing tube into which the guide wire can be inserted. A plurality of connector sockets are arranged along the tube and are electrically connected to electrical connection points along the insertion portion of the guide wire. The connecting point is connected to the aforementioned electrical conductor in the hollow tube of the guide wire. The guide wire is inserted into the storage tube and fixed by a fixture and a collar nut.

  The aforementioned programmable sensor adjustment unit is preferably constituted by a PGA309 programmable analog sensor conditioner schematically illustrated in FIG. The PGA 309 is specifically designed for resistance bridge sensor products and includes three main gain blocks for measuring different input bridge sensor signals. Thus, as described above, the signal representative of the measured physiological change is adapted such that a signal is generated according to the format required by the monitor. The PGA 309 can be configured to be used with an internal or external reference voltage. In a specific example, an external reference voltage of + 5V is supplied to the PGA 309.

  Thus, the adjustment unit generates an analog output voltage associated with the sensor signal so that the measured physiological change is read out by the physiological monitor.

  Since each sensor element is an individual component in its characteristics, each sensor assembly has a component unit, preferably an electrically erasable programmable read only memory (EEPROM). This memory contains individual calibration data obtained during calibration of the sensor elements that function for each individual sensor wire assembly. This calibration is performed in conjunction with the manufacture of the sensor wire assembly. The calibration data is taken into evaluation parameters such as voltage correction and temperature deviation.

The bridge pressure sensor is preferably excited from the PGA 309 by an excitation voltage V _EXC generated by the PGA 309. Alternatively, the pressure sensor may be excited from a separate energy source, such as a battery or capacitor means.

  The PGA309 circuit may be excited from a separate energy source (although it may be the same as or different from the energy source that excites the sensor), such as a battery or capacitor means, or the physiological monitor or combined energy source Excited by energy obtained from The energy source may be charged by the excitation voltage.

For example, for the excitation voltage V _EXC generated by the PGA 309 circuit, the bridge output voltage (V _IN1 −V _IN2 ) is a voltage proportional to the pressure applied to the sensor. Therefore, the sensor output voltage (V _IN1 −V _IN2 ) (sensor signal in FIG. 3) of this bridge is proportional to the pressure applied to the sensor, and changes with the applied excitation voltage with respect to the applied pressure. Is done. This sensor output voltage is preferably compensated for temperature changes at the sensor location and applied to the PGA 309. The PGA309 circuit also includes a gain block for adjusting the output signal from the circuit and used in addition to the output amplification unit.

According to another preferred embodiment, a processing unit, preferably a microprocessor (eg PIC16C770, shown in dotted lines in FIG. 3), is provided to process the analog output voltage V _OUT of the conditioned sensor. Adapt. The output voltage is supplied through the PGA309 programmable analog sensor regulator. The analog output signal from the PGA309 circuit is A / D converted before being sent to the processing unit. In order to adapt the sensor signal to the BP22 signal standard, the sensor signal may be further processed before being sent to the physiological monitor. For example, digital data (eg, 12-bit words) representing the signal measured by the sensor element and the reference voltage are sent to a multiple digital-to-analog converter (DAC), preferably provided in the processing unit. The manufactured product is sent to the monitor (after being filtered) and is proportional to the measured sensor signal and the reference voltage.

If pulse width modulation is required, the circuit schematically shown in FIG. 7 may be used. Here, the signal representing the measured change is used to generate a pulse train by opening and closing the reference voltage V _REF according to an opening and closing signal from the processing unit. The pulse train is filtered and the resulting voltage is a function of the measurement signal and a reference voltage.

  The sensor wire assembly may be directly coupled to the physiological monitor via the coupling means. In some cases, the pin structure of the connecting means is not compatible with what can be connected to the physiological monitor. In such a case, an adapter is installed between the connecting means and the physiological monitor. Link. The adapter may be a single unit or may have a cable that interconnects the two parts of the adapter. One of the two parts is adapted to the coupling means and the other part is connected to the physiological monitor.

  According to another embodiment, the communication between the sensor wire assembly and the physiological monitor is performed wirelessly. This is achieved by integrating a wireless communication unit (not shown) into the assembly. For example, a wireless communication unit is provided in a modified wire coupler and a wireless communication connection is established with an external physiological monitor using established communication protocols such as Bluetooth.

  The sensor wire assembly according to the present invention can be sterilized before use.

  The present invention is not limited to the preferred embodiments described above. Various substitutions, modifications and equivalents are possible. Therefore, the above examples should not be taken as limiting the scope of the invention, which is defined by the appended claims.

  As described above, the sensor wire assembly according to the present invention can easily and accurately measure physiological changes in a living body, and can greatly reduce the manufacturing cost. It is useful for medical devices that measure physiological changes in a living body.

It is a figure which shows an example of the guide wire to which the sensor concerning a prior art applicable to this invention was attached. 1 schematically shows a sensor wire assembly for measuring physiological changes in a living body according to the present invention. FIG. 1 is a block diagram schematically illustrating a sensor signal adaptation circuit according to the present invention. FIG. FIG. 2 is a block diagram schematically illustrating a sensor assembly according to a preferred embodiment of the present invention. 1 is a view showing a wire coupler according to a preferred embodiment of the present invention, in which the connector is in an assembled state. FIG. 1 is a view showing a wire connector according to a preferred embodiment of the present invention, in which the connector is in an unassembled state. FIG. 6 is a simplified diagram of a circuit for adapting a sensor signal to a BP22 standard (or related portion of the standard) using pulse width modulation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Sensor guide wire 102 Hollow tube 103 Core wire 104 1st spiral part 105 2nd spiral part 106 Jacket or sleeve 107 Dome-shaped tip 108 Sensor element or sensor chip 109 Electrical lead 110 Opening 301 Guide wire 308 Sensor element 311 Balloon catheter 312 Sensor signal matching circuit 313 Male connector 314 Female connector 315 Connection cable 316 Physiological monitor

Claims (16)

A sensor element for measuring a physiological change in a living body and generating a sensor signal corresponding to the change;
A sensor wire for measuring physiological changes, comprising a sensor wire at the tip of the sensor element and a guide wire adapted to be inserted into the living body to position the sensor element in the living body・ Assembly:
Furthermore, it has a sensor signal adaptation circuit as an integrated part, which is supplied with the sensor signal and automatically generates an output signal in a standard format in correlation with the sensor signal, A sensor wire assembly wherein the measured physiological change is read out by an external physiological monitor. A sensor element for measuring a physiological change in a living body and generating a sensor signal corresponding to the change;
A guide wire having the sensor element at its tip and adapted to be inserted into the living body to position the sensor element in the living body;
A connecting cable connected to the guide wire via the wire connector;
A sensor wire assembly for measuring said physiological change having said guide wire at its distal end:
Furthermore, it has a sensor signal adaptation circuit as an integral part, the adaptation circuit being arranged in the wire connection base, the adaptation circuit being fed with the sensor signal, correlated with the sensor signal and output A sensor wire assembly characterized in that a signal is automatically generated in a standard format whereby the measured physiological change is read out by an external physiological monitor.   The sensor wire assembly according to claim 1 or 2, wherein the standard format is a BP22-standard or a related part of the BP22-standard.   Sensor wire assembly according to claim 1 or 2, characterized in that the sensor signal adaptation circuit comprises a programmable sensor adjustment unit, a calibration unit, an energy means and an output amplification unit.   The sensor wire assembly of claim 4, wherein the programmable sensor conditioning unit is a PGA309 programmable analog sensor regulator.   3. A sensor wire assembly according to claim 1 or 2, further comprising coupling means for coupling to an input / output coupler of the physiological monitor.   Sensor wire assembly according to claim 6 or 1, characterized in that the adaptation circuit is arranged in the coupling means.   And further comprising a connecting cable, the connecting cable having a wire connector, connected to the guide wire via the wire connector, the adapting circuit being disposed in the wire connector, 2. A sensor wire assembly according to claim 1, comprising a wire at its tip.   The sensor wire assembly of claim 1, further comprising a wireless communication unit that establishes a wireless communication connection to the external physiological monitor using an established communication protocol, such as Bluetooth.   9. Sensor sensor according to claim 4 or 8, characterized in that the wire coupler comprises a circuit casting containing the programmable sensor adjustment unit, the calibration unit, the energy means and the output amplification unit. Wire assembly.   3. A sensor wire assembly according to claim 1 or 2, wherein the sensor signal adaptation circuit is energized via the physiological monitor.   3. A sensor wire assembly according to claim 2, wherein the sensor signal adaptation circuit is energized by energy means such as battery means or capacitor means which are an integral part of the assembly.   13. A sensor wire assembly according to claim 12, wherein the energy means is disposed within the wire coupler.   3. A sensor wire assembly according to claim 1 or 2, wherein the sensor element is energized via the sensor signal adaptation circuit.   Sensor wire assembly according to claim 1 or 2, characterized in that the sensor element is energized by separate energy means, for example battery means or capacitor means, which are an integral part of the assembly.   3. The sensor wire assembly according to claim 1, wherein the sensor wire assembly is sterilized before use.

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