GB2123965A - A cannular sensor and a method of measuring polarographic PO2 using the sensor - Google Patents
A cannular sensor and a method of measuring polarographic PO2 using the sensor Download PDFInfo
- Publication number
- GB2123965A GB2123965A GB8318587A GB8318587A GB2123965A GB 2123965 A GB2123965 A GB 2123965A GB 8318587 A GB8318587 A GB 8318587A GB 8318587 A GB8318587 A GB 8318587A GB 2123965 A GB2123965 A GB 2123965A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sensor
- cannular
- probe
- sensing
- measuring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 6
- 239000000523 sample Substances 0.000 claims description 17
- 238000003780 insertion Methods 0.000 claims description 8
- 230000037431 insertion Effects 0.000 claims description 8
- 239000012528 membrane Substances 0.000 claims description 6
- 239000011248 coating agent Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 3
- 210000001124 body fluid Anatomy 0.000 claims 1
- 239000010839 body fluid Substances 0.000 claims 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 238000005259 measurement Methods 0.000 description 4
- 210000003205 muscle Anatomy 0.000 description 4
- 210000001519 tissue Anatomy 0.000 description 4
- 229910021607 Silver chloride Inorganic materials 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 210000000056 organ Anatomy 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 2
- 229920002994 synthetic fiber Polymers 0.000 description 2
- 241000282326 Felis catus Species 0.000 description 1
- 206010028980 Neoplasm Diseases 0.000 description 1
- 239000007767 bonding agent Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000009545 invasion Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue
- A61B5/14542—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue for measuring blood gases
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue
- A61B5/1468—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using chemical or electrochemical methods, e.g. by polarographic means
- A61B5/1473—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using chemical or electrochemical methods, e.g. by polarographic means invasive, e.g. introduced into the body by a catheter
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6846—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
- A61B5/6847—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive mounted on an invasive device
- A61B5/6848—Needles
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Animal Behavior & Ethology (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Medical Informatics (AREA)
- Veterinary Medicine (AREA)
- Surgery (AREA)
- Biophysics (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
A cannular sensor having a plurality of embedded, filamentary electrodes (3), is constructed in such a way that it is possible to pick up a large number of measured values. For this purpose, the measuring surfaces (5) of the electrodes (3) are arranged on the wall surface (7) of the cannular sensor lying one after the other in the longitudinal direction and are provided with separate, electrical connections. The cannular sensor may be advantageously used in a method for measuring polarographic PO2 for the preparation of PO2 histograms. Each electrode is connected, in succession to a measuring circuit and a bias voltage is applied to all the electrodes that are not connected to the measuring circuit. <IMAGE>
Description
SPECIFICATION
A cannular sensor and a method of measuring polarographic P02 using the sensor
This invention relates to a cannular sensor and a method of measuring polarographic P02 using the sensor.
Various embodiments of cannular sensors for polarographic oxygen measurements are known.
Thus, for example, in the paper by W.J. Whalen and
J.l. Spande entitled "A hypodermic needle P02 electrode", J. Appl.Phyiol.: Respirat.Environ.Exercise Physiol. 48(1), (1980) 186-187, there is described a needle electrode in which 10 to 20 filamentary electrodes, which are firmly embedded in a casing tube with synthetic resin, lie at the point of the tubular casing which serves as an anode. Compensation must be made for the parallel connection of the measuring surfaces by establishing the average value of different individual measured values.
For various uses it seems advantageous to record the local tissue oxygen pressure, for example in muscle tissues, in the form of a PO2 histogram. In a publication by D.W. Libbers, entitled "Die
Bedeutung des lokalen Gewebesauerstoffdruckes und des PO2-Histrogrammes für die Beurteilung der
Sauerstoffversorgung eines Organes" in Prakt.A nästh.12(1977) 184-193, published by Georg Thieme,
Stuttgart it is shown that inside organs and muscles the local oxygen partial pressures very locally to a great extent.If a large number of PO2 pressure values is determined, for example, inside the coat of a muscle, and the individual pressure values are organised into corresponding classes, over which the percentage number of the measured values in question, relative to the total number of the measurements, is plotted, then a PO2 histogram is given having the form of an unsymmetrical frequency distribution. A shift towards lower PO2 values indi- cates a deterioration in the oxygen supply of the muscle tissue.
As a large number, usually more than a hundred, of PO2 measured values must be detected for measurements of this kind, difficulties arise in obtaining these measured values, for example through advancement and shifting of singular or multiple insertion probes.
In accordance with one aspect of the present invention there is provided a cannular sensor or probe having an external, elongate, sensing suface and a plurality of filamentary electrodes with sensing, end regions which lie at the sensing surface of the sensor, wherein said end regions are spaced apart, in a longitucdinal direction, along the length of the sensing surface.
Although the word "cannular" is usually used to describe a tubular instrument for insertion into a cavity or tumour, it will be appreciated that in the present specification the word "cannular" is not necessarily used to described a hollow member, but is used as an indication to practitioners in the art of the context in which the sensor of the present invention may be taken.
Preferably each electrode is provided with a separate electrical connection.
Preferably the electrodes are firmly embedded in an interior region of the sensor. The sensing, end regions may be covered with a selectively permeable resin and may, when the sensing surface is substantially cylindrical, lie along a line of the cylindrical surface.
The number of sensing, end regions advantageously lies in the range of from 5 to 150, the diameter of the end regions amounting to approximately 20 to 30,am.
If the reference electrode is not mounted separately near the puncture point of the sensor, it can be advantageous to arrange the reference electrode on the outside of the sensor. A plane, metallic coating of the membrane, which covers the measuring surfaces, seems suitable. The coating can be made of a silver/silver chloride film. To facilitate the insertion of the sensor the latter can advantageously be provided with an insertion point, in the form of a tapering, leading end region.
Thus, in an embodiment of this aspect of the present invention, the end regions or measuring surfaces are arranged on the wall surface of the sensor lying one after the other in the longitudinal direction and are provided with separated electrical connections. In this way an advantageous, rectilinear arrangement of measuring sufaces, which each enter into gaseous interchange, with the surrounding tissue through the intermediary of the covering membrane, can develop on the wall surface of the cannular sensor.
A single turn of the sensor, which can be carried out in a sensitive manner about few degrees without substantial discomfort for the person who is to be examined, results in a new series of measured values so that with a sensor of such a kind, which comprises, for example, 100 adjacent measuring surfaces, 1,000 P02 measuring points are obtained without difficulties in 10 sections of turn and can be recorded separately.
In accordance with another aspect of the present invention there is provided a method of measuring polarographic P02, using a cannular sensor or probe, wherein each electrode is connected, in succession, to a measuring circuit and wherein a bias voltage of polarisation is applied to the others of the electrodes, which are not connected to the measuring circuit, when one of the electrodes is connected to the measuring circuit.
For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which the Figure shows a cannular sensor, according to an embodiment of the present invention, in isometric representation and partly in section.
In a cannular carrier 1, which has an insertion point 2 at its distal end, seven filamentary electrodes 3 lie one after the other on a wall surface. These electrodes 3 are connected to a multiwire coaxial cable 4 and have end regions which are offset by 900 so that the sensing or measuring surfaces 5 lie on the wall surface 7 of the cannular carrier 1. There may be provision for an intermediate piece 6 at the junction between the cannular carrier 1 and the connection of the coaxial cable 4.
The free, interior spaces of the cannular carrier 1 and the intermediate piece 6 are filled up with epoxy resin up to the connection of the multiwire coaxial cable 4, and in this way the electrodes 3 and their measuring surfaces 5 are fixed and are insulated against each other.
The cannular sensor is constructed by using a commercially available cannula, for use once only, having an outside diameter of 0.5-1 mm. The said cannula is slit on one side to a length of approximately 0.1 mm. After the electrodes, having end regions which are offset at right angles, have been inserted, the cannula is connected to a low pressure system, with the aid of which an epoxy resin bonding agent can be drawn into the interior space of the cannular carrier 1. After this synthetic material has hardened, the cannula is smoothed on its outside wall surface, whereby the measuring surfaces 5 develop. A membrane coat can be produced through immersion into an appropriate synthetic material solution. Subsequently, if necessary, a silver/silver chloride film may be applied on a section of the membrane coat and in this way a reference electrode is formed.The electrodes are then connected with the conductors in the coaxial cable, and a coaxial protective surface of the cable is bonded to the reference electrode.
The sensor has a simple overall construction which is not very susceptible to disturbance. Further the sensor makes it possible to obtain a large number of measured values with little invasion of the tissue. The discomfort of the person who is to be examined is considered to be slight, as a large number of different measured values can be tested without having to change the place, thereby damaging the tissue, or newly orientate the sensor.
If the cannular sensor or probe is used to carry out polarographic P02 measurements when inserted into an insertion channel, the measuring equipment is constructed in a known way from two circuit sections, of which a first circuit section comprises a constant voltage source (approximately 1.5 volt) and a asecond, measuring circuit section comprises an indicating and/or recording measuring instrument having series-connected amplifier. The measured values are advantageously recalled in such a way that the measuring surface 5, which forms a cathode, whose value is to be scanned, is connected to the measuring circuit section, which is connected to a measuring instrument, while all the other measuring surfaces 5, also forming cathodes, remain connected to the first circuit section, which is generating a bias voltage of polarisation, until their measured value is to be recalled. To produce a histogram it is necessaryto scan the values of the individual measuring surfaces or cathodes 5 quickly one after the other (preferably within a second) before the oxygen concentration in the insertion channel changes substantially.
Claims (11)
1. A cannular sensor or probe having an external, elongate, sensing surface and a plurality of filamentary electrodes with sensing, end regions which lie at the sensing surface of the sensor, wherein said end regions are spaced apart, in a longitudinal direction, along the length of the sensing surface.
2. A cannular sensor or probe as claimed in claim 1, wherein each electrode is provided with a separate electrical connection.
3. A cannular sensor or probe as claimed in claim 1 or 2, wherein the electrodes are firmly embedded in an interior region of the sensor.
4. A cannular sensor or probe as claimed in any preceding claim, wherein the sensing, end regions are covered with a selectively permeable membrane.
5. A cannular sensor or probe as claimed in any preceding claim, wherein the sensing surface of the sensor is substantially cylindrical, and wherein the sensing, end regions lie along a line of the cylindrical surface.
6. A cannular sensor or probe as claimed in any preceding claim, wherein the number of sensing, end regions lies in the range of from 5 to 150.
7. A cannular sensor or probe as claimed in any preceding claim, wherein a reference electrode is arranged on the external surface of the sensor.
8. A cannular sensor or probe as claimed in claims 4 and 7, wherein the reference electrode is constructed as a metallic coating which covers the permeable membrane.
9. A cannular sensor or probe as claimed in any preceding claim, wherein the sensor or probe has a tapering leading end region to assist in insertion of the sensor or probe into a body fluid or tissue.
10. A cannular sensor or probe substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.
11. A method of measuring polarographicPO2, using a cannular sensor or probe according to any preceding claim, wherein each electrode is connected, is succession, to a measuring circuit and wherein a bias voltage of polarisation is applied to the others of the electrodes, which are not connected to the measuring circuit, when one of the electrodes is connected to the measuring circuit.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19823225871 DE3225871A1 (en) | 1982-07-10 | 1982-07-10 | CANNEL SENSOR AND MEASUREMENT METHOD THEREFOR |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8318587D0 GB8318587D0 (en) | 1983-08-10 |
| GB2123965A true GB2123965A (en) | 1984-02-08 |
| GB2123965B GB2123965B (en) | 1986-03-26 |
Family
ID=6168138
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8318587A Expired GB2123965B (en) | 1982-07-10 | 1983-07-08 | A cannular sensor and a method of measuring polarographic po2 using the sensor |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE3225871A1 (en) |
| GB (1) | GB2123965B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2163055A (en) * | 1984-08-14 | 1986-02-19 | Consiglio Nazionale Ricerche | Intracardiac catheter |
| GB2215846A (en) * | 1988-03-23 | 1989-09-27 | Nat Res Dev | Method and apparatus for measuring the type and concentration of ion species in liquids |
| WO2001094928A2 (en) * | 2000-05-09 | 2001-12-13 | Leszlauer Zoltan | Electrode structure for coaxial, electro-chemical sensors made of metal |
| WO2002006823A1 (en) * | 2000-07-15 | 2002-01-24 | Alexander Wannenwetsch | Measuring probe |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4741343A (en) * | 1985-05-06 | 1988-05-03 | Massachusetts Institute Of Technology | Method and apparatus for measuring oxygen partial pressure and temperature in living tissue |
| DE3537919A1 (en) * | 1985-10-24 | 1987-04-30 | Kessler Manfred | ARRANGEMENT FOR STABILIZING A GAS REFERENCE ELECTRODE |
| DE3700119A1 (en) * | 1987-01-03 | 1988-07-14 | Inst Diabetestechnologie Gemei | IMPLANTABLE ELECTROCHEMICAL SENSOR |
| DE3725597A1 (en) * | 1987-08-01 | 1989-02-09 | Siegert Gmbh | Ionometric sensor |
| DE10112384A1 (en) * | 2001-03-15 | 2002-09-26 | Uwe Thomas | Ultra-micro electrode, for use as a probe for topographical and chemical analysis, has a cylindrical body with a center electrode fiber, and parallel outer electrode fibers insulated against the center fiber |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1454066A (en) * | 1975-01-03 | 1976-10-27 | Vital Signs Inc | Multipurpose oesophageal probe |
-
1982
- 1982-07-10 DE DE19823225871 patent/DE3225871A1/en not_active Withdrawn
-
1983
- 1983-07-08 GB GB8318587A patent/GB2123965B/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1454066A (en) * | 1975-01-03 | 1976-10-27 | Vital Signs Inc | Multipurpose oesophageal probe |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2163055A (en) * | 1984-08-14 | 1986-02-19 | Consiglio Nazionale Ricerche | Intracardiac catheter |
| GB2215846A (en) * | 1988-03-23 | 1989-09-27 | Nat Res Dev | Method and apparatus for measuring the type and concentration of ion species in liquids |
| GB2215846B (en) * | 1988-03-23 | 1992-04-22 | Nat Res Dev | Method and apparatus for measuring the type and concentration of ion species in liquids |
| WO2001094928A2 (en) * | 2000-05-09 | 2001-12-13 | Leszlauer Zoltan | Electrode structure for coaxial, electro-chemical sensors made of metal |
| WO2001094928A3 (en) * | 2000-05-09 | 2002-06-06 | Zoltan Leszlauer | Electrode structure for coaxial, electro-chemical sensors made of metal |
| WO2002006823A1 (en) * | 2000-07-15 | 2002-01-24 | Alexander Wannenwetsch | Measuring probe |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2123965B (en) | 1986-03-26 |
| GB8318587D0 (en) | 1983-08-10 |
| DE3225871A1 (en) | 1984-01-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |