DE102012012180A1 - Device for in-vivo measurement of oxygen partial pressure of intravascular fluid, has polarographic measurement unit for oxygen partial pressure measurement, which is arranged along catheter - Google Patents

Abstract

The device has a catheter (1) with a distal catheter end and a proximal catheter end (5) and a flexible, fluid-tight catheter wall. A polarographic measurement unit is integrated in the catheter and provides a measuring chamber partially limited by the catheter wall. The measuring chamber is filled with electrolyte fluid, in which a polarographic cathode and an anode are arranged. The catheter wall is only permeable to oxygen. The catheter has a flexible metallic catheter tip formed of metallic radio-opaque guide wire. Another polarographic measurement unit for oxygen partial pressure measurement is arranged along the catheter and spaced from the former measurement unit in the region between distal and proximal catheter ends.

Description

Technical area

The invention relates to an apparatus for in vivo measurement of at least the oxygen partial pressure of an intravascular fluid with a catheter having a distal and proximal catheter end and a flexible, fluid-tight catheter wall with a plurality of integrated into the catheter polarographic measurement units, the one through the Catheter wall at least partially limiting measuring chamber provides, which is filled with an electrolyte liquid, in which a polarographic cathode and an anode are arranged, wherein only the measuring chamber delimiting the catheter wall is formed permeable to oxygen. In one embodiment of the invention, individual measurement data are transmitted wirelessly to an evaluation and monitoring station.

State of the art

Devices of the above type are for in vivo measurement of oxygen partial pressure within an intravascular fluid residing in human or animal vasculature. In order to be able to carry out such measurements on the living organism, the measurement sensor system required for the oxygen partial pressure measurement is integrated within a catheter and as a rule consists of electrochemical oxygen sensors based on the amperometric measurement principle, also referred to as the Clark principle. Such oxygen partial pressure sensors have a measuring chamber which is fluid-tight in relation to the environment and within which an electrolyte liquid is contained. In addition, two electrodes protrude into the measuring chamber, of which the cathode consists of a suitable noble metal, preferably platinum, and the anode is typically made of silver, preferably with a silver chloride surface. The measuring chamber is at least partially enclosed by an oxygen-permeable membrane, so that oxygen from the environment diffuses against the diffusion resistance through the membrane into the measuring chamber filled with the electrolyte liquid. In this case, the amount of oxygen entering, which enters the electrolyte liquid of the measuring chamber per unit of time, depends on the oxygen partial pressure of the environment. An electrical voltage is applied between the two electrodes so that oxygen is reduced at the cathode made of noble metal, which is also referred to as the working electrode. In this case, a so-called diffusion limiting current flows, which is proportional to the oxygen partial pressure within the adjacent to the measuring chamber environment, especially since the metrologically detectable diffusion limit current depends directly on the diffusing through the oxygen diffusion membrane amount of oxygen into the measuring chamber.

For local detection of the oxygen partial pressure in certain intracorporeal vascular or tissue areas goes from the US 4,582,064 a catheter system with a catheter needle forth at the catheter tip an oxygen diffusion-permeable membrane is provided, under which a polarographic measurement unit according to the Clark principle, as explained above, is provided.

A suitable trained for brain oxygen partial pressure measurement measuring device is in the document EP 0 880 339 B1 described. The probe has at its distal end via a thin flexible tube which encloses a space filled with electrolyte liquid space in which a polarographic cathode with a limited surface and an anode are arranged, wherein the tube is oxygen permeable at least in the measuring range. Between the electrodes, a polarographic measuring voltage is applied, which is generated by means of a voltage source connected to the probe on the proximal side.

The known measuring catheters serve primarily to determine the partial pressure of oxygen according to the Clark principle at discrete intracorporeal measuring sites. However, if it is the oxygen partial pressure at several locations within certain vascular or tissue areas to determine it is necessary to move the respective catheter-based probe intracorporeally and to place at various new sites. However, this leads to an additional burden on the vascular or tissue areas. In addition, no simultaneous, ie. H. simultaneous measurements of oxygen partial pressure can be made.

In contrast to the above catheter systems, which represent predominantly rigid catheter instruments and the oxygen partial pressure on electrochemical pathways to detect the Clark principle are beyond catheter catheter systems with optical fibers are known, which are quite flexible and designed in blood-filled hollow organs oxygen saturations of the Detecting hemoglobin or the oxygen loading of the erythrocytes by means of light emission. Of the WO 03/017840 A1 is a related flexible catheter, along the lumen of which run at least three optical fiber cables, the ends dull end and two of which light fiber optic cables emit light each having different wavelengths and the third optical fiber cable from the distal environment receives backscattered light and traced back for evaluation on the proximal side.

The publication US 2009/0156921 A1 describes a device in which a measurement of blood oxygen saturation is performed through a lateral opening of an ablation catheter. Both measurement arrangements mentioned above are based on the method in which the oxygen saturation in the blood is determined by means of an optically differential absorption method in which light with at least two different wavelengths is used, of which one wavelength is not and the other wavelength is the oxygen contained in the blood is absorbed.

In addition to the knowledge about the oxygen partial pressure of an intravascular fluid, it is very helpful, if not necessary, to record further physiological or chemical properties of an intravascular fluid, such as the pH, the carbon dioxide partial pressure, as well as for a comprehensive diagnosis the temperature as well as the pressure of the intravascular fluid. In one Article by A. Zollinger et al. "Accuracy and clinical performance of a continuous intra-arterial blond-gas monitoring system during thoracoscopic surgery", British Journal of Anesthesia 1997, 79: p. 47-52 , reference is made to a catheter system comprising a plurality of individual sensors capable of detecting both the partial pressure of oxygen as well as the carbon dioxide partial pressure, the pH and the blood temperature. The measuring sensor used here for detecting the oxygen partial pressure is based on the electrochemical measuring principle according to the Clark principle, the sensors for detecting the carbon dioxide partial pressure and the pH are designed as optical sensors, whereas the temperature sensor consists of a suitably selected thermocouple. All sensors are located immediately adjacent to each other within the inner lumen of a catheter which is filled with an oxygen-permeable medium and surrounded by an oxygen-permeable catheter wall.

Patients in need of external cardiovascular and ventilatory support systems, such as extracorporeal membrane oxygenation (ECMO), often have varying oxygen partial pressures and / or pH levels in partially adjacent vascular regions, thereby often interpreting the patient's oxygenation status is very difficult. Thus, in particular in the region between the body's circulatory and oxygen support as well as the machine-generated blood flow of the support system to different oxygen partial pressures or pH values in various organs come, which complicates an adequate therapy of all organs with oxygen or a targeted ventilation therapy of the patient at least considerably. Different oxygen concentrations in different parts of the body are also problematic in multi-organ failure, since differentiated oxygen therapy may be required within different organs with different oxygen consumption. Thus, even with gradually differing oxygen concentrations within individual organs or in individual vessel sections before and after vessel sites with different pH values, ischemic or toxic partial reactions of organ parts can occur, which significantly worsen the chances of recovery. Thus, arterial oxygen partial pressures well above 300 mmHg increase the likelihood of oxygen-induced toxic complications, whereas arterial oxygen partial pressures below 50 mmHg can cause ischemic organ damage.

Presentation of the invention

It is an object of the present invention to provide a device for in vivo measurement of at least the partial pressure of oxygen of an intravascular fluid having a catheter having a distal and a proximal catheter end and a flexible, fluid-tight catheter wall with a first polarographic measurement unit integrated in the catheter, which provides an at least partially bounded by the catheter wall measuring chamber, which is filled with an electrolyte liquid, in which a polarographic cathode and an anode are arranged, with only the measuring chamber delimiting the catheter wall is oxygen permeable, educate in such a way that it should be possible to To detect oxygen partial pressure multifocal at different intracorporal sites, without having to place the catheter multiple times. In this way, it should be achieved to largely avoid intracorporeal tissue irritation. In addition, it should be possible to carry out the multifocal measurements at different measuring sites as simultaneously as possible in order to obtain a diagnosable basis for the current distribution of the oxygen partial pressure within specific organ or body areas in this way.

The solution of the problem underlying the invention is specified in claim 1. The solution ideas advantageously further-forming features are the subject of the dependent claims and the further description with reference to the exemplary embodiments.

According to the invention, a device for in vivo measurement of at least the partial pressure of oxygen of an intravascular fluid with a catheter having the features of the preamble of claim 1 is characterized in that along the catheter, spaced from the first measuring unit, in the region between the distal and proximal end of the catheter, a second polarographic measuring unit suitable for oxygen partial pressure measurement is arranged.

By providing at least two separately formed, polarographic measuring units, which are designed to detect the oxygen partial pressure along a common catheter, it is possible to simultaneously detect the oxygen partial pressure at two different intracorporeal measuring points, without moving the catheter or correspondingly again to have to place.

Each individual polarographic measuring unit includes a measuring chamber which is fluid-tight with respect to the catheter and which is delimited axially relative to the catheter by correspondingly fluid-tight partitions and on the other hand by the catheter wall. The catheter wall radially delimiting the respective measuring chamber is at least partially made of an oxygen-permeable material, so that dissolved oxygen in the intravascular fluid can diffuse through this catheter wall area into the interior of the measuring chamber. The measuring chamber is filled with an electrolyte fluid. Within each measuring chamber, in a manner known per se, the oxygen entering the measuring chamber, counter to the diffusion resistance, is reduced and correspondingly detected at the working electrode made of a noble metal, preferably of platinum, the so-called polarographic cathode.

The at least two, preferably three or more polarographic measuring units formed and arranged separately along the catheter and used for measuring the oxygen partial pressure, may be in shape and size, ie. H. with respect to their axial length to the catheter, be the same or different, depending on the location and size of the intracorporeal to be detected vascular or tissue areas. The diameter of the individual polarographic measuring units is identical to the rest of the catheter diameter, so that the catheter, which is flexible over its entire length, has a uniform catheter cross-section and can thus be introduced into the intracorporeal circulation path through tissue channels as unobstrusively as possible.

In order to enable exact intracorporeal positioning and ultimately verifiable localization of the catheter and in particular the polarographic measuring units distributed along the catheter relative to intracorporeal measuring locations, each polarographic measuring unit is provided with a radiopaque marker, for example in the form of a ring-shaped sleeve, which is flush the catheter outer wall at least on one side a measuring chamber axially bounded directly to the catheter.

In a first embodiment variant, the catheter designed in accordance with the invention has at least one inner lumen, preferably a plurality of inner lumens, of which an inner lumen, which extends completely from the proximal to the distal end of the catheter, is used to pass a guide wire. Furthermore, it is necessary to supply the polarographic electrodes provided in each individual measuring chamber with an electrical measuring voltage and to supply the measuring current which can be detected with the aid of the electrodes to an evaluation unit provided correspondingly with extracorporeality. Electrical connection lines thus run through a further lumen to be provided along the catheter and connect the polarographic electrodes provided in the individual measuring chambers with external supply and evaluation units.

In contrast, a second preferred variant of the embodiment of the device according to the invention provides a wireless connection to the individual polarographic measuring units arranged along the catheter. For example, the polarographic electrodes present in the measuring units are connected to a radio connection unit integrated within the catheter, preferably in the form of a Blutooth or WLAN radio unit, via which at least measuring signals to a radio unit located outside the catheter can be transmitted. At the same time, the at least two measuring units arranged along the catheter for purposes of supplying electrical energy each have an induction unit integrated within the catheter, which can be brought into interaction with an external electromagnetic field and in this way interpose the polarographic measuring voltage required for the measurement of the oxygen partial pressure generates both electrodes and also serves to power the radio units. The wireless implementation of the device according to the invention allows a significant reduction in the diameter of the catheter to only a few millimeters and depending on applicable and future catheter technology down to the submicrometer range, especially as all lumens within the catheter can be dispensed with. In particular, there is no need for wire feed to the individual measuring chambers, which in the case of the provision of two, three or more measuring chambers along the catheter decisively contribute to the macroscopic diameter formation of the catheter. It is also possible to dispense with a guide wire extending through the catheter, provided that a flexible, radiopaque wire is attached to the catheter tip, with which the catheter can be navigated during insertion into the catheter intracorporeal vascular system using appropriate monitoring techniques, such as X-ray imaging technology, is possible.

To additionally, as described above for oxygen partial pressure measurement to detect a further physiological or chemical intravascular fluid value, in the longitudinal direction of the catheter at least one suitable for Sauerstoffpartialdruckmessung polarographic measuring unit medium or immediately adjacent to the carbon dioxide partial pressure, short pCO ₂ and a the pH continuously measuring unit arranged. The additional measuring units can be connected in the same way as the polarographic measuring unit for detecting the oxygen partial pressure via connecting lines with external, extracorporeal provided supply and evaluation units as well as wirelessly using modern wireless technology based on Bluetooth or WLAN.

Optionally, it is also conceivable to provide at least one pressure-detecting measuring unit and / or a temperature-detecting measuring unit in addition to the measuring units for detecting the oxygen partial pressure, the carbon dioxide partial pressure and the pH. For the design of each optionally additionally to be provided measuring units can be used on known sensor technology.

The solution according to the device thus enables a simultaneous, multi-local measurement of the oxygen partial pressure and optionally of other chemical and / or physiological properties of an intravascular fluid, such as the carbon dioxide partial pressure, the pH, the prevailing pressure and the temperature with the help of only one single catheter.

Since the device according to the invention measures the oxygen partial pressure measurement with the aid of an electrochemical measuring unit, the oxygen saturation in the blood can be determined independently of the hemoglobin, which would not be possible within the scope of a light emission measurement.

Of course, it is possible to provide the catheter for purposes of intracorporeal fixation with suitable inflatable means, such as with a inflatable at the distal end balloon, which is dilatable about a filling lumen in a suitable manner. Also, such an inflatable balloon mounted at the distal end serves to facilitate the introduction of the catheter into a vascular system through which blood passes, in that the balloon is flushed into the desired target region together with the catheter.

Furthermore, the device according to the invention provides a further lumen, a so-called injection lumen, along the catheter, via which suitable temperature-controlled or fluid-displaced liquids can be injected specifically into the vascular system through which fluid flows. For example, with the help of such an injection lumen, blood flow rates and cardiac output can be measured exactly with the aid of the so-called thermo-dilution method. For this purpose, the outlet opening of the additional injection lumen is at a defined distance upstream of a, preferably attached to the catheter end thermal sensor, which is able to determine the flow rate of the intravascular fluid based on a detectable temperature change. For this purpose, a injection fluid which is colder than the intravascular fluid is injected from the injection lumen, the overflow of which at the location of the thermal sensor generates a temperature change and thus a measurement signal.

Brief description of the invention

The invention will now be described by way of example without limitation of the general inventive idea by means of embodiments with reference to the drawings. Show it:

1 schematic overall view of a solution designed according to the device for the multifocal detection of oxygen partial pressure and the detection of the carbon dioxide partial pressure and pH value using a single catheter,

2a , b longitudinal cross-section through a measuring unit suitable for oxygen partial pressure measurement along the catheter,

3 Longitudinal section through a chemiluminescence measuring cell suitable for detecting the carbon dioxide partial pressure and the pH,

4 Cross section through wire-based, multi-lumen catheters, as well

5 Longitudinal section through wireless catheter

Ways to carry out the invention, industrial usability

In 1 is an overall view of the solution designed according to device for in vivo measurement of at least the oxygen partial pressure of an intravascular fluid with a multifunctional catheter 1 shown. The catheter made of a biocompatible polymer material 1 has a high flexibility transverse to the catheter extension. This is said to swing through the trained catheter presentation in 1 to be expressed. The catheter 1 is formed mehrlumig, ie the catheter wall comprises a plurality of individual, mutually separated hollow channels 6 . 7 . 8th . 10 . 14 extending from the proximal end 5 of the catheter 1 , which is in the form of a channel guide bushing, far different distal side through the catheter 1 extend. At least one catheter 1 completely penetrating lumen, a so-called balloon lumen 8th , is for purposes of inflation of a distally provided balloon 4 provided, the proximal side via a connector 9 , Preferably in the form of a three-way cock with a pressure source is connectable. Alternatively to or in combination with inflation of the balloon 4 through the balloon lumen 8th may be a guidewire (not shown) through this lumen 8th for purposes of insertion and navigation of the catheter 1 in or within the intracorporeal vascular or tissue area.

In the in 1 illustrated embodiment, the catheter has 1 via three, the oxygen partial pressure sensing polarographic measurement units 2.1 . 2.2 . 2.3 of which the first pO ₂ measuring unit 2.1 immediately adjacent to the distal end of the catheter, a second pO ₂ measuring unit 2.2 proximally spaced to the first pO ₂ measuring unit 2.1 attached and a third pO2 measuring unit 2.3 with a clear distance on the proximal side to the second pO ₂ measuring unit 2.2 is appropriate. With the help of the pO ₂ measuring units 2.1 . 2.2 . 2.3 All of which are based on the same measuring principle, namely the Clark principle, and thus capable of detecting the oxygen partial pressure in an electrochemical manner and thus independently of the hemoglobin content of the blood, it is possible to use three simultaneous oxygen partial pressure measurements at three different measuring locations single catheter 1 perform. The measurement signals originating from the individual pO2 measurement units are all wired via a multi-core pO ₂ cable harness 10 discharged, the end via a switching and connection station 11 with a signal amplifier 12 connected to the further signal evaluation with a computer-based monitor unit 13 connected is.

The individual pO ₂ measurement units 2.1 . 2.2 . 2.3 are with a radiopaque marker 24 provided, which conforms like a ring to the catheter wall immediately after the respective pO2-measuring unit.

In the in 1 illustrated embodiment extends along the catheter 1 between the second pO ₂ measuring unit 2.2 and third pO ₂ measuring unit 2.3 another, the carbon dioxide partial pressure and the pH-detecting measuring unit 3 which preferably works on the chemiluminescence measuring principle. Alternatively to the illustrated arrangement of the pCO ₂ - and pH measuring unit 3 can also each two, three or more such the pCO ₂ or pH-measuring measuring units 3 along the catheter 1 be provided, for example in the same number as those along the catheter 1 provided pO ₂ measuring units 2.1 . 2.2 . 2.3 ,

In the same way as in the case of the pO ₂ measuring units, the measured values obtained in the pCO ₂ measurement and in the pH measurement are also transmitted via a cable harness 14 guided separately proximally to the outside and via a switching and connection station 15 with a signal amplifier 16 connected, the amplified measuring signals to a CO ₂ partial pressure and the pH-determining evaluation 17 forwards.

In a further embodiment of the solution according to the catheter 1 sees this for purposes of detecting the blood flow rate and cardiac output a lateral catheter opening 25 ago, through which a cooled liquid over the lumen 7 intracorporeally within a blood-bearing vessel. Using a distal end on the catheter 1 attached temperature sensor 26 in the form of a thermistor, the overflow of the liquid which has been cooled with respect to the blood can be detected and thus closed back to the flow velocity of the blood flow. These are the at the thermistor 26 detected sensor signals via the cable guide 27 to an extracorporeal evaluation unit 32 , which is designed to be suitable for temperature monitoring led out.

Further, as an option for pressure sensing within the intravascular fluid, the entire catheter is included 1 interspersing lumen 6 provided, which can be used as an alternative to performing a guide wire for pressure detection, by the proximal side of the lumen 6 can be connected to an external pressure monitor (not shown).

All along the catheter 1 provided measuring units nestle flush with the catheter outer wall and form a common smooth uniform catheter outer wall surface.

The dimensioning of the total catheter length as well as the number and the mutual distance of the individual measuring units to each other are specifically determined by the anatomy and by predetermined measurement tasks, especially since the oxygen partial pressure and the pH values may be different at different locations within the body, especially in the case of a patient for whose treatment extracorporeal oxygen generators are used.

In 2a is a longitudinal section through an oxygen partial pressure sensing unit 2.1 . 2.2 . 2.3 shown. Such a measuring unit has a measuring chamber sealed in a fluid-tight manner 28 on that with an electrolyte fluid 19 is filled. The measuring chamber is axially on the proximal and distal sides of oxygen-impermeable wall parts 18 limited. Radial side is the measuring chamber 28 from an oxygen-permeable catheter wall 20 surround. In the center of the measuring chamber 28 runs a lumen 29 , among other things, electrical connection cable 23 for the energy and signal supply of the individual measuring units.

The measuring units designed to detect the oxygen partial pressure 2.1 . 2.2 . 2.3 each within the measuring chamber 28 a working electrode made of precious metal 21 as well as an anode 22 between, an operating voltage for purposes of oxygen reduction at the working cathode 21 is created. Depending on the oxygen content of the catheter wall 20 circulating intravascular fluid (not shown) are capable of delivering varying amounts of oxygen through the oxygen permeable catheter wall 20 into the measuring chamber 28 diffuse with the help of the polarographic measuring unit 2.1 . 2.2 . 2.3 is detected.

The catheter wall 20 preferably consists exclusively in the region of the measuring chamber 28 from an oxygen-permeable material, for example in the form of a metallic or plastic film, the axially on both sides of the measuring chamber 28 fluid-tight flush with the otherwise flexible, but oxygen-impermeable catheter wall adjacent. Thus, the polarographic measuring unit can be understood as a measuring cylinder unit implemented along the catheter or completely integrated. For purposes of exact positioning of the in 2 illustrated polarographic measuring unit 2.1 . 2.2 . 2.3 relative to an intracorporeal measuring site, is additionally a radiopaque marker 24 immediately adjacent to the measuring chamber 82 mounted in the catheter wall, which are visible on X-ray image recordings for a surgeon.

In 2 B is an alternative embodiment for the catheter 1 with a polarographic measuring unit integrated therein 2.1 . 2.2 . 2.3 shown. This is the way the catheter points 1 an at least two-layered catheter wall 20 on, with an inner wall layer 20.1 and an outer wall layer 20.2 , The inner wall layer 20.1 consists of an oxygen-permeable material, whereas the outer catheter wall layer 20.2 is oxygen impermeable. In the area of the polarographic measuring unit 2.1 . 2.2 . 2.3 is the outer catheter wall 20.2 interrupted, leaving the electrolyte-filled measuring chamber 28 exclusively through the inner, ie oxygen-permeable catheter wall 20.1 separated from the environment surrounding the catheter. Same as the one in 2a Illustrated embodiment are also in the case of 2 B two polarographic electrodes 21 . 22 within the measuring chamber 28 each axially axially on both sides of oxygen-impermeable, fluid-tight wall sections 18 is limited. Outside the measuring chamber 28 is located immediately adjacent to this one induction unit 30 , which interacts inductively with an electromagnetic alternating field prevailing externally to the catheter, to thereby supply an electrical supply voltage between the two polarographic electrodes 21 . 22 to create. For detecting and removing the between the two polarographic electrodes 21 . 22 detected measuring signals representing the measured oxygen partial pressure, serves a likewise with both electrodes and with the induction unit 30 connected radio connection unit 31 which wirelessly transmits the acquired measurement signals to an external evaluation and control unit. Likewise, it is possible to have corresponding external control signals by means of the radio connection unit 31 to recieve.

With the help of wireless energy and signal transmission between the polarographic measuring unit 2.1 . 2.2 . 2.3 and an external power supply unit as well as a control and evaluation unit can be adapted to a cable guide that requires space within the catheter in accordance with the method described in US Pat 2a illustrated embodiment, see electrical wiring harness 23 , be waived. This makes it possible to significantly reduce the catheter cross-section and make the entire catheter miniaturizable.

For the realization of the carbon dioxide partial pressure and the pH value measuring unit 3 are used in per se known sensor techniques, which can be carried out as it were, as in the case described above, for measuring the oxygen partial pressure in the form of an electrochemical measuring unit as well as in the form of a chemiluminescent sensor. In 3 is a longitudinal sectional view through a chemiluminescent sensor shown schematically. In contrast to the embodiment according to 2a , b, in which the polarographic measuring unit for detecting the oxygen partial pressure is illustrated, in the case of the carbon dioxide partial pressure measurement and the pH measurement, the measuring chamber 28 with an optically sensitive polymer 32 filled, such as polyurethane hydrogel, poly-HEMA, cellulose or polysiloxanes. The sensitive polymers 32 are mixed with chromophores. The the measuring chamber 28 radially surrounding catheter wall 20 is, as it were, permeable to oxygen, and also axially of oxygen-impermeable wall sections 18 limited. Inside the measuring chamber 28 are at least two optical light guides 33 . 34 arranged, by the light into the optically sensitive polymer 32 which interacts with the polymer and produces fluorescence effects whose fluorescent light is emitted from the same or different optical waveguide 34 is detected and forwarded to a corresponding light detector unit. Both the light supply and discharge via the respective light guide 33 . 34 takes place in the 3 illustrated embodiment along a central cable guide 23 to a proximal side extracorporeal control and evaluation provided. Likewise, it is also possible to realize the chemiluminescence measurement with the aid of integrated components within the catheter, to the energy supply and also Meßsignalzu- and derivation can be made of non-contact method, such as the illustrated induction method for energy transfer and the described radio communication technology for Transmission of appropriate control and measuring signals.

4 FIG. 12 illustrates a cross-section through a conventional wire delivery catheter design through suitably within the catheter. FIG 1 led lumen 29 . 6 . 9 . 8th , The cross section runs through a pO2 measuring unit 2.1 holding a measuring chamber 28 provides, at least partially, of an oxygen-permeable catheter wall 20 is limited and in the anode 22 and cathode 21 are placed. In a lateral lumen area 38 run the lumen 6 for the catheter wire or the external blood pressure measurement, the balloon lumen 8th as well as the lumen 7 for the thermo-dilution measurement as well as a lumen for a cable connection 27 from the thermistor to the monitor system. The area of the catheter wall 20 who has the lumen area 38 is limited radially outward not or at least not necessarily oxygen permeable formed. Inside the measuring chamber 28 centrically penetrating lumens 28 the lumens run 10 . 14 for the pCO ₂ as well as pH cables.

Also in connection with the embodiment according to 1 said sensors for detecting the pressure within an intravascular fluid and also thermosensors for detecting temperature changes may also be formed without wired connections to an extracorporeal control unit. 5 illustrates such a catheter device. Along the catheter 1 are in each case three separate pO ₂ measurement units 2.1 . 2.2 . 2.3 arranged.

A pressure measuring unit 35 is characterized, for example, by a length of the catheter 1 or optionally at the distal catheter end to be provided measuring chamber in which there is negative pressure relative to the ambient pressure, which is connected via a flexible membrane with the catheter flowing around the intravascular fluid in operative connection. The membrane is part of an inductive capacitive resonance circuit, so-called LC circuit whose resonant vibration behavior is due to the diaphragm deflection, which in turn is influenced by the blood pressure. The measuring chamber is connected to an induction-sensitive sensor, which interacts with an externally applied magnetic field, via which both the corresponding power supply and a continuous signal detection can be realized.

In the same way, the thermosensor suitable for carrying out thermodilution measurements is 26 attached to the distal end of the catheter and measuring the temperature change of the blood upon injection of cooled fluids to determine the cardiac output, to operate by wireless signal interrogation.

Although the measurement of a change in temperature at the probe can be preferably by means of a liquid injection into a through the catheter 1 realize extending lumen, which is extracorporeally connected to a liquid pump. On the other hand, the measurement of the temperature of an endogenous fluid, eg. As the blood temperature, inter alia after application of intravascular applied cooling fluids without an additional catheter lumen possible. Nevertheless, it is part of the design to operate the thermocouple attached to the distal end of the catheter in the same way inductively as well as with the aid of radio communication technology known per se, in order to ensure, on the one hand, the power supply and, on the other hand, the continuous measurement signal removal.

Between the second and third pO ₂ measuring unit 2.2 and 2.3 is along the catheter 1 a pCO ₂ and pH measuring unit 3 intended. Because the catheter 1 has no lumen, he also offers no way to carry a guidewire. To navigate the catheter 1 for intra-oral insertion and positioning, the catheter tip is a flexible, radiopaque wire 36 provided, which can be pre-bent in a suitable manner.

The catheter system designed in accordance with the invention thus serves for the exact, multifocal and simultaneous determination of the degree of oxygenation, the pH and optionally the CO ₂ partial pressure, the intravascular pressure and the temperature within a cavity filled with bodily fluid, ie for example in the arterial and venous blood, plasma , Urine or cerebrospinal fluid. Due to the possibility of miniaturization, in particular when using a wireless signal and power supply, it is possible to use the catheter system in intracorporeal vessel areas, the require correspondingly small sized catheter diameter. Advantageously, the catheter has 1 at its proximal end via a fixed rotary device 37 with which an operator can accurately position the catheter by metered rotation of the catheter 1 can make about its longitudinal axis.

Basically, the catheter can be used in arterial as well as venous vascular systems of the heart, brain and kidneys, genital and intrauterine systems as well as in the CSF space.

LIST OF REFERENCE NUMBERS

1

catheter

2.1, 2.2., 2.3

Sauerstoffpartialdruckmesseinheiten

3

Carbon Dioxide and pH measurement units

4

balloon

5

Proximal catheter end, channel guide bush

6

Lumen for catheter wire or external blood pressure measurement

7

Lumen for thermo-dilution measurement

8th

balloon lumen

9

Three-way valve

10

pO2 cable

11

Switching station of the oxygen measuring regions

12

signal amplifier

13

PC and monitor system

14

pCO2 and PH cables

15

Switching station of the PH measuring unit

16

signal amplifier

17

PC and monitor system

18

Oxygen-impermeable wall

19

electrolyte fluid

20

Oxygen permeable diffusion membrane

20.1

Oxygen permeable catheter wall layer

20.2

Oxygen-impermeable catheter wall layer

21

cathode

22

anode

23

Isolated electrical cable, wiring harness

24

Radiopaque marking

25

Lateral catheter opening to a catheter lumen

26

Thermistor, thermocouple

27

Cable management with connection to PC and monitor

28

measuring chamber

29

lumen

30

induction unit

31

radio unit

32

Fluorescent polymer

33

optical fiber

34

optical fiber

35

Pressure-measuring unit

36

Radiopaque wire

37

Fixed rotary device

38

Lateral area of the lumbar

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 4582064 [0003]
• EP 0880339 B1 [0004]
• WO 03/017840 Al [0006]
• US 2009/0156921 A1 [0007]

Cited non-patent literature

• Article by A. Zollinger et al. "Accuracy and clinical performance of a continuous intra-arterial blond-gas monitoring system during thoracoscopic surgery", British Journal of Anesthesia 1997, 79: p. 47-52 [0008]

Claims (15)

Device for in vivo measurement of at least the oxygen partial pressure of an intravascular fluid with a catheter having a distal and proximal catheter end and a flexible, fluid-tight catheter wall, with a first polarographic measuring unit integrated into the catheter, which comprises a measuring chamber delimiting at least partially through the catheter wall is provided, which is filled with an electrolyte liquid, in which a polarographic cathode and an anode are arranged, wherein only the measuring chamber delimiting the catheter wall is oxygen permeable, characterized in that along the catheter, spaced from the first measuring unit in the region between the distal and proximal Catheter end, a second suitable for oxygen partial pressure measurement polarographic measuring unit is arranged. Device according to claim 1, characterized in that at least one third polarographic measuring unit suitable for oxygen partial pressure measurement is arranged along the catheter, in each case spaced from the first and second measuring unit in the region between the distal and proximal catheter ends. Apparatus according to claim 1 or 2, characterized in that only the measuring chamber limiting oxygen-permeable catheter wall is made of a different material, as the material from which the rest of the flexible, fluid-tight catheter wall is made and has a catheter outer wall side, flush with the catheter outer wall side, the remaining flexible, fluid-tight catheter wall. Apparatus according to claim 3, characterized in that the measuring chamber partially delimiting the catheter wall is formed in the form of a metallic or plastic-based wall portion, which is materially connected to the other flexible, fluid-tight catheter wall. The device of claim 1 or 2, characterized in that the flexible, fluid-tight catheter wall comprises at least two layers of material, an inner catheter wall layer surrounding an inner catheter lumen and made of an oxygen-permeable material, and an outer catheter wall layer applied to the inner catheter wall layer and is made of an oxygen-impermeable material, and that the outer catheter wall layer at those wall regions provides recesses corresponding to the catheter walls bounding the measuring chambers. Device according to one of claims 1 to 5, characterized in that in the longitudinal direction of the catheter in each case at least one suitable for Sauerstoffpartialdruckmessung polarographic measurement unit medium or immediately adjacent to a carbon dioxide partial pressure, short pCO ₂ , and pH continuously detected measuring unit is arranged , Apparatus according to claim 6, characterized in that the pH and pCO ₂ value detecting measuring unit comprises a chemiluminescence sensor or an electrochemical measuring unit. Device according to one of claims 1 to 7, characterized in that in the longitudinal direction of the catheter in each case at least one suitable for oxygen partial pressure measurement polarographic measurement unit directly or indirectly adjacent to a pressure-detecting measuring unit is arranged. Device according to one of claims 1 to 8, characterized in that in the longitudinal direction of the catheter in each case at least one suitable for Sauerstoffpartialdruckmessung polarographic measurement unit directly or indirectly adjacent to a temperature-detecting measuring unit is arranged. Device according to one of claims 1 to 9, characterized in that the measuring units are connected for purposes of supply of electrical energy and the Meßsignalabführung each within the catheter proximal cables extending, which are connectable to at least one located outside the catheter control and evaluation , Device according to one of claims 1 to 9, characterized in that the measuring units are connected for purposes of Meßsignalabführung each with at least one integrated within the catheter radio connection unit via which at least measurement signals to a radio unit located outside the catheter, and in that the measuring units are each connected, for purposes of supplying electrical energy, to at least one induction unit integrated within the catheter, which can be brought into interaction with an external electromagnetic field. Device according to one of claims 1 to 11, characterized in that the catheter has at least one inner lumen through which a guide wire can be guided from the proximal catheter end to the distal end of the catheter. Device according to one of claims 1 to 12, characterized in that the catheter has at least one inner lumen through which the At the proximal end of the catheter, a balloon located at the distal end of the catheter is inflatable. Apparatus according to claim 11, characterized in that the catheter comprises a flexible catheter tip of a metallic, radiopaque guide wire Device according to one of claims 1 to 14, characterized in that the measuring chamber at least the first polarographic measuring unit, at least one radiopaque marker provides.

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