WO1989011819A1 - Low resistance electrical pick-up - Google Patents
Low resistance electrical pick-up Download PDFInfo
- Publication number
- WO1989011819A1 WO1989011819A1 PCT/GB1989/000631 GB8900631W WO8911819A1 WO 1989011819 A1 WO1989011819 A1 WO 1989011819A1 GB 8900631 W GB8900631 W GB 8900631W WO 8911819 A1 WO8911819 A1 WO 8911819A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- low resistance
- silver
- resistance electrical
- coated
- electrical pick
- Prior art date
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/43—Detecting, measuring or recording for evaluating the reproductive systems
- A61B5/4306—Detecting, measuring or recording for evaluating the reproductive systems for evaluating the female reproductive systems, e.g. gynaecological evaluations
- A61B5/4343—Pregnancy and labour monitoring, e.g. for labour onset detection
- A61B5/4362—Assessing foetal parameters
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
- A61B5/279—Bioelectric electrodes therefor specially adapted for particular uses
- A61B5/28—Bioelectric electrodes therefor specially adapted for particular uses for electrocardiography [ECG]
- A61B5/283—Invasive
- A61B5/288—Invasive for foetal cardiography, e.g. scalp electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/49117—Conductor or circuit manufacturing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/49117—Conductor or circuit manufacturing
- Y10T29/49204—Contact or terminal manufacturing
Abstract
A low resistance electrical pick-up, such as a fetal scalp electrode (17), comprises a stainless steel wire (10), with an arcuate needle (18) on the outer end of a radial arm (19), the arcuate needle (18) being plated with nickel (14) and then silver (15), optionally with an intervening layer of copper (16), and then an area (11) of the silver layer (15) at least on the outside of the curve of the needle (18), and possibly spaced from the point of the needle, is chloridized and then coated with bio-compatible plastics (12).
Description
LCW RESISTANCE ELECTRICAL PICK-UP
This invention relates to a low resistance electrical pickup - more particularly - but not exclusively - for use in a fetal scalp electrode or other biosensing electrode.
It is known that a chloridized silver wire can constitute a low resistance electrical pick-up, but the silver chloride is not bio-compatible.
The primary object of the invention is to overcome this difficulty.
Another object is to provide a fetal scalp electrode or other biosensing electrode with a low resistance electrical pick-up capable of subcutaneous introduction.
According to the present invention, a low resistance electrical pick-up comprises a length of wire having an area of its surface coated with silver chloride and the area of silver chloride coated ith a bio-compatible plastics material. Such a material is that known under the registered trade mark "Tecoflex".
The wire may be a silver wire having a length chloridized and then coated with bio-compatible plastics over the chloridized length, and any further non-chlor idized length or lengths of the wire may also be coated with the bio-compatible plastics; alternatively, any further length or lengths of the wire may be coated with a non-conducting varnish.
According to an aspect of the invention of independent significance, a low resistance electrical pick-up comprises a length of stainless steel wire having a first coating layer of nickel, and a subsequent coating layer of silver,
optionally with an intervening layer of copper, an area of the silver layer being chloridized and then coated with bio- compatible plastics material, e.g., "Tecoflex". A further length or lengths of non-chloridized silver layer may be coated with a non-conducting varnish.
In a particular application of the invention to a fetal scalp electrode or other biosensing electrode of the type having an arcuate needle of stainless steel - which may serve as a reference electrode and/or measuring electrode and/or introducer for a separate electrode - the arcuate needle is plated with nickel and then silver, optionally with an intervening layer of copper, and an area of the silver layer at least on the outside of the curve of the needle, and possibly spaced from the point of the needle, is chloridized and then coated ith bio-compatible plastics, and the remainder of the silver layer is coated with a non-conducting varnish.
The coating of the chloridized silver area can be given a thin coating of "Tecoflex" by dipping it into a solution of "Tecoflex" in tetrahydrof uran (THF) which is allowed to set (approximately 12 to 24 hours) before the remaining areas of the electrode are painted ith a non¬ conducting varnish.
A number of embodiments of the invention will now be described by way of example only, with reference to the accompanying diagrammatic drawings, in which:-
Figure 1 is a fragmentary enlarged side elevation of a basic low resistance electrical pick-up in accordance with the invention;
Figure 2 is an even greater enlarged cross-section on the line II-II of Figure 1;
Figure 3 corresponds to Figure 1 but illustrates an alternative basic embodiment of the invention;
Figure 4 also corresponds to Figure 1 but illustrates a preferred embodiment of the invention;
Figure 5 is an enlarged cross-section on the line V-V of Figure 4;
Figure 6 corresponds to Figure 5 but includes a slight modification;
Figure 7 is a greatly enlarged skeletal perspective view of the head member of a "Sur gicraf t-Copeland" fetal scalp electrode (FSE) including a low resistance electrical pick-up in accordance with the invention;
Figure 8 is a fragmentary ECG trace obtained using a
FSE as in Figure 7; and
Figure 9 is a fragmentary ECG trace obtained with an un-modified "Surgi craft- Co pel and" FSE for comparison with the trace of Figure 8, the paper speed in Figure 8 being twice that in Fi gur e 9.
The thickness of the coating layers in Figures 1 to 6 have been greatly exaggerated, even compared to the enlarged scale, for the sake of clarity.
In Figures 1 and 2, a low resistance electrical pick¬ up comprises a length of wire 10 having an area 11 of its surface coated with silver chloride and the area of silver chloride coated with a bio-compatible plastics material 12, such as that known under the registered trade mark "Tecoflex".
In Figure 3r a length of silver wire 10 has a length
11 chloridized and then coated with bio-compatible plastics
12 over the chloridized length.
Any further non-chloridized length (or area) or lengths 13 of the wire 10 in either of the above embodiments may be coated with a non-conducting varnish.
However, the preferred embodiment illustrated by Figures 4 and 5 comprises a length of stainless steel wire 10 having a first coating layer 14 of nickel, and a subsequent coating layer 15 of silver, an area (or length) 11 of the silver layer being chloridised (indicated in Figure 4 by the thicker broken line) and then coated ith bio-compatible plastics material, e.g., "Tecoflex". Further lengths 13 of non-chloridized silver layer 15, and preferably also adjacent exposed lengths of the nickel layer 14 and stainless steel wire 10 may be coated with a non-conducting varnish.
Figure 6 corresponds closely to Figure 5 but indicates a layer 16 of copper between the nickel layer 14 and the silver layer 15.
In Figure 7f the head member 17 of a "Surgicraft- Copeland" FSE, as described in GB-PS 1316 072 or GB-PS 1 523
263 (or US-PS 4151 835) , has an arcuate needle 18 formed on the outer end of a radial arm 19 from a main stainless steel wire 10, the arcuate needle 18 being plated with nickel 14 and then silver 15 (optionally with an intervening copper layer, not shown, but refer to Figure 6) , an area (not shown) of the silver layer at least on the outside of the curve of the needle 18, and possibly spaced from the point of the needle, is chloridized and then coated with bio-compatible
plastics 12, and the remainder of the silver layer is coated with a non-conducting varnish.
The fundamental advantage of the low resistance "Surgicraf t-Copeland" FSE of Figure 7 can be appreciated by comparing Figures 8 and 9. The bare stainless steel arcuate needle electrode of the unmodified "Surgicraf t-Copeland" FSE is highly resistant to low frequency electrical activity, so the trace of Figure 9 is erratic, and it also shows enormous variability because of the added effect of f eto-maternal movement. In contrast, the trace of Figure 8 shows that low frequency electrical activity from the fetus can be picked up with great accuracy by the low resistance "surgicraft- Copeland" FSE of Figure 7, and consistent waveforms (P,QRS and T waves) of the cardiac cycle can be more easily identified. This allows more complex fetal ECG waveform analysis and reduces the need for extensive signal processing and averaging, as has been necessary with the unmodified "Surgicraf t-Copeland" FSE.
The invention is also applicable to other types of fetal scalp electrodes, such as the spiral electrodes of Corometrics Medical Systems Inc. US Re 28990, the clip-like electrodes of T.C. Neward EP 0 007 702, and the outwardly splayed electrodes of Kontron Inc. EP 0 099077, or to other electrodes or probes, such as the outwardly splayed anchor needles in the cardiac probe of . Mohl EP 0 004 967.
Claims
1. A low resistance electrical pick-up comprising a length of wire having an area of its surface coated with silver chloride and the area of silver chloride coated with a bio-compatible plastics material.
2. A low resistance electrical pick-up as in Claim
1, wherein the wire is a silver wire having a length chloridized and then coated with bio-compatible plastics over the chloridized length.
3. low resistance electrical pick-upas in Claim
2, wherein, any further non-chloridized length or lengths of the wire is/are coated with the bio-compatible plastics.
4. low resistance electrical pick-u as in Claim 2, wherein any further non-clor idized length or lengths of the wire is/are coated with a non-conducting varnish.
5. A low resistance electrical pick-up comprising a length of stainless steel wire having a first coating layer of nickel, and a subsequent coating layer of silver, an area of the silver layer being chloridized and then coated with bio-compatible plastics material.
6. A low resistance electrical pick-up as in Claim
5, wherein an intervening layer of copper is provided between the nickel and silver layers.
7. A low resistance electrical pick-up as in Claim 5 or Claim 6, wherein a further length or lengths of non- chloridized silver layer is/are coated with a non-conducting varnish.
8. A fetal scalp electrode or other biosensing electrode of the type having an arcuate needle of stainless steel, wherein the arcuate needle is plated with nickel and then silver and an area of the silver layer at least on the outside of the curve of the needle, is chloridized and then coated with bio-compatible plastics, and the remainder of the silver layer is coated with a non-conducting varnish.
9. A fetal scalp electrode or other biosensing electrode as in Claim 8, wherein an intervening layer of copper is provided between the nickel and silver layers.
10. A low resistance electrical pick-up substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.
11. A low resistance electrical pick-up substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.
12. A low resistance electrical pick-up substantially as hereinbefore described with reference to Figures 4 and 5 of the accompanying drawings.
13. A low resistance electrical pick-up substantially as hereinbefore described with reference to Figure 6 of the accompanying drawings.
14. A fetal scalp electrode substantially as hereinbefore described with reference to Figure 7 of the accompanying drawings.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP89906414A EP0422029B1 (en) | 1988-06-08 | 1989-06-07 | Low resistance electrical pick-up |
DE68922215T DE68922215D1 (en) | 1988-06-08 | 1989-06-07 | ELECTRIC SENSOR WITH A LOW RESISTANCE. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB888813570A GB8813570D0 (en) | 1988-06-08 | 1988-06-08 | Low resistance electrical pick-up |
GB8813570 | 1988-06-08 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1989011819A1 true WO1989011819A1 (en) | 1989-12-14 |
Family
ID=10638288
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1989/000631 WO1989011819A1 (en) | 1988-06-08 | 1989-06-07 | Low resistance electrical pick-up |
Country Status (7)
Country | Link |
---|---|
US (1) | US5183043A (en) |
EP (1) | EP0422029B1 (en) |
AT (1) | ATE120942T1 (en) |
DE (1) | DE68922215D1 (en) |
ES (1) | ES2015710A6 (en) |
GB (1) | GB8813570D0 (en) |
WO (1) | WO1989011819A1 (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5330525A (en) * | 1993-04-29 | 1994-07-19 | Medtronic, Inc. | Epicardial lead having dual rotatable anchors |
GB2370776B (en) * | 2000-09-13 | 2004-10-13 | Neoventa Medical Ab | Fetal scalp electrode |
JP2002228668A (en) * | 2001-01-31 | 2002-08-14 | Shimadzu Corp | Automatic sampler |
JP4728571B2 (en) * | 2003-10-31 | 2011-07-20 | 古河電気工業株式会社 | Manufacturing method of silver-coated stainless steel strip for movable contacts |
GB0902069D0 (en) | 2009-02-06 | 2009-03-25 | Neoventa Medical Ab | Fetal electrode assembly and fetal electrode |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4589418A (en) * | 1982-12-06 | 1986-05-20 | Cardiac Pacemakers, Inc. | Coating for silver/silver chloride reference electrode |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3568662A (en) * | 1967-07-07 | 1971-03-09 | Donald B Everett | Method and apparatus for sensing bioelectric potentials |
US3989038A (en) * | 1974-11-25 | 1976-11-02 | Neward Theodore C | Fetal electrode and biopsy device |
DE3502913C1 (en) * | 1985-01-29 | 1986-07-03 | Günter Prof. Dr.rer.nat. 5100 Aachen Rau | Sensor for non-invasive detection of electrophysiological values |
-
1988
- 1988-06-08 GB GB888813570A patent/GB8813570D0/en active Pending
-
1989
- 1989-06-07 AT AT89906414T patent/ATE120942T1/en not_active IP Right Cessation
- 1989-06-07 WO PCT/GB1989/000631 patent/WO1989011819A1/en active IP Right Grant
- 1989-06-07 DE DE68922215T patent/DE68922215D1/en not_active Expired - Lifetime
- 1989-06-07 EP EP89906414A patent/EP0422029B1/en not_active Expired - Lifetime
- 1989-06-07 US US07/613,904 patent/US5183043A/en not_active Expired - Fee Related
- 1989-06-08 ES ES8902005A patent/ES2015710A6/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4589418A (en) * | 1982-12-06 | 1986-05-20 | Cardiac Pacemakers, Inc. | Coating for silver/silver chloride reference electrode |
Non-Patent Citations (3)
Title |
---|
IEEE Transactions on Biomedical Engineering, vol. BME-24, no. 2, March 1977, (New York, US), G.E. Loeb et al.: "Parylene as a chronically stable, reproducible microelectrode insulator", pages 121-128 * |
Medical Progress through Technology, vol. 9, nos. 2/3, 1982, Springer Verlag (Berlin, DE), M.R. Neuman: "Physical and chemical sensors for medical instrumentation", pages 95-104 * |
Obstetrics and Gynecology, vol. 30, no. 2, August 1967, E.H. Hon: "Instrument and Method. Instrumentation of fetal heart rate and fetal electrocardiography", pages 281-286 * |
Also Published As
Publication number | Publication date |
---|---|
EP0422029B1 (en) | 1995-04-12 |
US5183043A (en) | 1993-02-02 |
EP0422029A1 (en) | 1991-04-17 |
ES2015710A6 (en) | 1990-09-01 |
GB8813570D0 (en) | 1988-07-13 |
DE68922215D1 (en) | 1995-05-18 |
ATE120942T1 (en) | 1995-04-15 |
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