GB1579376A

GB1579376A - Electrode apparatus for picking up signals from the skin surface of living creatures

Info

Publication number: GB1579376A
Application number: GB14723/77A
Authority: GB
Original assignee: DROH R
Current assignee: DROH R
Priority date: 1976-04-10
Filing date: 1977-04-07
Publication date: 1980-11-19
Also published as: FR2347021A1; FR2347021B1

Description

(54) IMPROVEMENTS RELATING TO ELECTRODE APPARATUS FOR PICKING UP SIGNALS FROM THE SKIN SURFACE OF LIVING CREATURES (71) I, ROLAND DROH, DR. MED. a citizen of the Federal Republic of Germany of Hardenbergstrasse 14, 5880 Ludenscheid, Federal Republic of Germany do hereby declare the invention for which I pray that a patent may be granted to me and the method by which it is to be performed to be particularly described in and by the following statement: The invention relates to electrode apparatus for picking up signals from the skin surface of living creatures.

Needle electrodes are known for taking off heart action voltages from the surface of the skin of living creatures, for example.

Such electrodes are stuck into the skin at the required take-off point and, if necessary, located by means of adhesive tape.

Collector electrodes on the other hand are constructed in the form of contact pads and are located at the extremities or on the breast of a patient by means of rubber bands.

With both known types, the electrodes are individual elements which have to be applied separately and this is time consuming and tiresome. Considerable preparatory work is necessary, in a similar manner, for taking off other signals from a patient's skin.

The present invention provides electrode apparatus for picking up electrical signals from the skin surface of a living creature, the apparatus comprising a support presenting a surface on which the living creature is intended to lie, a plurality of electrodes, some at least of which are designed for picking up heart action voltages produced by the heart action of a living creature lying on said surface, supported on, and fixedly attached to, said surface at predetermined spaced locations covering areas of said surface, the boundaries of such areas being spaced inwardly from the boundaries of said surface, and electrical leads for connecting the electrodes in circuit with diagnostic apparatus or with means for transmitting signals representing measured values to diagnostic apparatus, said leads passing through the support.

The support, which is preferably formed as a wedge-shaped cushion, can be pushed under the back of a human patient with a single movement of the hand, the electrodes then being reliably applied to the skin of the patient by the weight of his own body. This ensures a satisfactory take-off of the signals to be measured which are then evaluated in conventional manner.

An apparatus according to the present invention, facilitates work in operating theatres, in particular, where time saving simplification of the manner of applying electrodes to a patient and thereafter removing them is particularly desirable.

Conveniently, said surface may be formed by a cover or overlay of the support so that, in the event of wear of the support proper, it can be replaced with little expense.

At least one of the electrodes may be designed to detect body temperature. This development renders it possible to monitor the patient's body temperature, possibly simultaneously with heart-action voltages, without any effort in handling, which is of particular importance for various applications, particularly during operations under anaesthesia, because variations which occur in temperature are important indications of a change in the patient's state. Thus a rise in temperature occurring during anaesthesia is an indication of the patient's intolerance of the anaesthetic used, which frequently could not be detected previously. This is a phenomenon which requires immediate counter-measures, for example cooling of the patient. In conjunction with the monitoring of the heart-action voltages, the simultaneous monitoring of the patient's temperature renders it possible to draw wider and more accurate conclusions regarding his state during examinations, operations etc. particularly under anaesthesia. The same applies to the measurement of the partial pressure of the patient's tissue oxygen and tissue CO2, so that a detecting element for specific partial pressures of gas in the patient's tissue can also be provided.

The detecting element for the body temperature may advantageously be disposed on or beside an earth electrode or collector electrode for heart-action voltages and be electrically connected to the earth electrode so that a lead which is in any case taken to the earth electrode can be used for the transmission of body temperature signals.

A neutral electrode for electric treatment of the patient may be provided, disposed on said surface of the support, and in turn connected to a lead rendering it possible to carry out electrical treatments on the patient, which may become necessary unexpectedly and quickly, without separate measures, which are otherwise usual, for applying a neutral electrode to the patient being necessary. At the same time, the cables can be combined in one lead which is an advantage for neatness and safety, particularly in operating theatres.

A device for measuring the pulse or measuring the peripheral blood pressure at a finger of a human patient being examined may be provided, for use in conjunction with the electrode apparatus, by means of two measuring members adapted to be applied to opposite sides of the finger and to be connected to evaluation equipment through connecting cables, with a measuring-member holder of resilient material, substantially in the form of a flexible tube, which can be drawn over the finger and on which the measuring members are held with a contact surface exposed at the inside.

Known devices for measuring the pulse or for measuring the peripheral blood pressure, particularly those with a measuring member which transmits light and a measuring member which receives light passing through the finger and modulated at the pulse frequency, are conventionally secured by a plaster or adhesive tape to a thumb or another finger of a person to be examined, after which the measuring arrangement has to be screened from the outside light. As a result, the application and removal of the known device is extremely expensive.

Furthermore, there is the risk of damaging the sensitive, unprotected measuring members, particularly when they are transported or put down in the un-applied state, together with their connecting lead. The measuring-member holder proposed avoids such labour and also the risk of damage.

When not in use, the device for measuring the pulse or for measuring the peripheral blood pressure may be accommodated, to particular advantage, in a tray or pocket provided for this purpose in the support of the electrode apparatus in which case a spring-driven roller may be provided in the tray or pocket to wind up the connecting cord.

Specific embodiments of the present invention will now be described by way of example and not by way of limitation with reference to the accompanying drawings in which: Fig. 1 shows a perspective view of an apparatus according to the invention, in a first embodiment, Fig. 2 shows a broken-away side view of a second embodiment of apparatus according to the invention, Fig. 3 shows a device for measuring the pulse at a patient's finger, and Fig. 4 shows a partial view of the apparatus, equipped with a device for measuring the pulse.

With reference to the accompanying drawings, Fig. 1 shows a support, designated as a whole by 1, in perspective view, which has a rectangular outline and increases in thickness in a wedge shape towards the end adjacent to a patient's head. The top surface of the support 1 contains contact elements 2, 3, 4 which form collector electrodes for taking off heart action voltages and which are connected to cables 5, 6 and 7 respectively. These cables 5, 6 and 7, which extend in the interior of the support 1 combine to form a lead 8 which is taken out of the end of the support 1 and which carries an attachment plug 9 at its end. Through this attachment plug 9, a connection can be established to an electrocardiograph and a temperature-indicating device.

Of the collector electrodes 2, 3 and 4, the collector electrode 2 serves as an earth electrode and is constructed in the form of an annular electrode, in the middle of which there is disposed a contact element 10.

Alternatively, the collector electrode 2 and contact 10 may be combined to form a circular unit, each forming one sector thereof.

This contact element 10 forms the sensor of an electrical detecting element for the body temperature and may, in turn, be constructed as an electrode. The temperature electrode 10 is electrically connected to the earth electrode 2 so that the cable 5 can be used for the transmission of measured values. Instead of this embodiment, the contact element 10 or the temperature electrode may also be disposed beside and separate from the earth electrode at the top of the support 1. In this case, a separate cable can lead to the attachment plug 9 or a length of cable may establish the connection to the cable 5.

In cases where an electrical connection between the electrodes 2, 10 and a joint use of the cable 5 is impossible or inappropriate, a changeover switch, illustrated diagrammatically at 11 may be introduced into the cable 5, which switch is provided with a second input and is connected, at the input side, to the temperature electrode 10 through a short length of cable 5'. This changeover switch 11 can connect one of the two inputs to its output selectively or continuously alternating periodically and so ensure the transmission of measured values from both electrodes 2, 10 via the main part of the cable 5.

Further provided in the top surface of the support 1 is a contact element 12 having a comparatively large area, which forms a neutral electrode for electrical treatment, for example electrosurgical operations etc.

This neutral electrode has its own cable 13 for an earth connection, which cable can be included in the lead 8. Instead, it is also possible to take the cable 13 out of the support 1 separately and to provide it with an attachment plug similar to the attachment plug 9. This is a particular advantage when the cables 5, 6, 7 are taken to the input of a measured-value transmitter which is illustrated diagrammatically at 14 and which is let into the support and permits a wireless transmission of measured values. Such a construction is particularly desirable in cases where there are considerable distances between the patient and the measurement indicating and/or recording equipment.

The earth electrode 2 and the neutral electrode 12 may be replaced by a single electrode unit. In this case, the neutral electrode may be annular and surround the earth electrode. Alternatively, the neutral electrode and the earth electrode may be combined to form a circular electrode unit the two electrodes each constituting one sector of the unit.

Figure 2 illustrates the apparatus of Figure 1 in an embodiment wherein the support 1 is united, through a flexible connecting strip 15, to a holding member 16 for a patient's head. This holding member 16 is constructed in the form of a hollow annular body, the interior of which is in communication with the interior of the support 1 through a connecting line 17. In this case, for example, the support 1 is inflatable and is provided with an air-filled interior 18 which, when the support is placed underneath a patient, is compressed under the bearing pressure of the body with the result that the air is displaced out of the interior 18, through the connecting line 17, into the interior of the holding ring, and inflates this to a greater or lesser extent. Instead, however, the holding ring 16 may also be constructed in the form of an enclosed member filled with air which is connected to the support 1 via the intermediate connecting strip 15. This is made flexible for adaptation to different body measurements so that the spacing between the annular member 16 and the support 1 can be adapted to the particular requirements.

As illustrated by broken lines in Figure 1, the electrodes may also be incorporated in an overlay 19 or cover for the support, in which then the electrical connecting lines 5, 6, 7 are simultaneously incorporated. This overlay may have a thickness of about 2 to 3 mm and be connected to the support proper, at its narrow sides, for example by means of press-studs 20. The overlay may consist of cloth, but preferably of plastics sheet for the purpose of more rapid cleaning.

The device for measuring the pulse, which is designated as a whole by 21 in Figure 3 consists, first, in conventional manner, of two measuring members 22 and 23 and a connecting cable 24 which, in the vicinity of the measuring members 22 and 23, branches into two branch cables 25 and 26 leading towards these and ends, at its opposite, free end, in an attachment plug 27 for the connection to evaluation equipment or to the support 1.

The device is further equipped with a measuring-member holder 28 of resilient foam plastics which is substantiallv in the form of a flexible tube or funnel with a wider opening 29 as an entrance for the finger and a narrower opening 30 as a free opening for the passage of the finger tip. In the region of the entrance 29, the measuring-member holder 28 is drawn out to form a tongue-like holding flap 31. The shape represented in section in the drawing, supplemented by the front half, coinciding in mirror-image but not illustrated, forms a one-piece shape which is closed all round.

For location inside the measuringmember holder, the substantially parallelepiped measuring members 22 and 23 are sunk in corresponding recesses in the inside of the foam plastics of the measuringmember holder 28, but they project with contact surfaces 32, 33 facing one another.

Furthermore the associated cable branches 25 and 26 extend through corresponding holes or slots through the foam plastics to the outside.

Alternative forms of embodiment or modifications, differing from the particularly appropriate form of embodiment described above, are possible in various ways, which permit simple handling and a reliable contact of the measuring members, shielded from the outside light. Thus various other, easily flexible or resilient materials, for example textiles, may be used, it being important for the location of the measuring members inside the measuring-member holder, not that there should be a possibility of sinking in the measuring member holder but simply that there should be the possibility of adequate fixing. Furthermore, the passage of the cable branches 25 and 26 through the measuring-member holder is not absolutely essential, they can be taken out internally to the opening 30 or to the entrance 29 without any disturbance during use. The measuring-member holder in the form of a flexible tube can also be closed at the end, but the opening is comfortable in view of the heat generated by the measuring members and furthermore it enables the measuring-member holder to be pulled appropriately far over the finger tip or the finger to compensate for different thicknesses of finger.

In order to integrate this device 21 in the measuring unit combined by the support 1, a connection (not illustrated) particularly a plug-in connection must be provided on the latter. In addition; as Figure 4 shows, a pocket or tray 33 may be provided in the support 1, preferably in a side wall, in which the device 21 can be safely and tidily accommodated when not in use. As illustrated, a roller 34, for example supported on a holder 35, is preferably provided for rolling up the connecting cable 24. The roller 34 may appropriately be equipped with a spring drive on the inside so that the cable 24 has to be pulled out against the force of the spring and rolls up automatically with the force of the spring on being released.

WHAT I CLAIM IS: 1. Electrode apparatus for picking up electrical signals from the skin surface of a living creature, the apparatus comprising a support presenting a surface on which the living creature is intended to lie, a plurality of electrodes, some at least of which are designed for picking up heart action voltages produced by the heart action of a living creature lying on said surface, supported on, and fixedly attached to, said surface at predetermined spaced locations covering areas of said surface, the boundaries of such areas being spaced inwardly from the boundaries of said surface, and electrical leads for connecting the electrodes in circuit with diagnostic apparatus or with means for transmitting signals representing measured values to diagnostic apparatus, said leads passing through the support.

2. Apparatus as claimed in claim 1 wherein the support is formed as a wedgeshaped cushion.

3. Apparatus as claimed in claim 1 or 2 wherein said surface is formed by a cover or overlay of the support.

4. Apparatus as claimed in any preceding claim wherein at least one of the electrodes is designed to detect body temperature.

5. Apparatus as claimed in claim 4 wherein the electrode for detecting body temperature is disposed at or near an earth electrode for detecting heart action voltages and is electrically connected to the earth electrode and has an electrical lead in common therewith.

6. Apparatus as claimed in claim 5 wherein a changeover switch is provided connecting the temperature electrode and the earth electrode with said common electrical lead.

7. Apparatus as claimed in any preceding claim wherein a detecting element for gas partial pressures in the tissue of a living creature lying on said surface of said support is disposed on said surface of the support.

8. Apparatus as claimed in any preceding claim further comprising a neutral electrode for electrical treatment of a living creature lying on said surface of the support.

9. Apparatus as claimed in claims 5 and 8 wherein the neutral electrode is united with said earth electrode to form a single electrode unit.

10. Apparatus as claimed in claim 9 wherein the neutral electrode is annular and surrounds the earth electrode.

11. Apparatus as claimed in claim 9 wherein the neutral electrode and the earth electrode are formed as sectors of a circular electrode unit.

12. Apparatus as claimed in any preceding claim including a signal transmitter disposed in the support, said transmitter being electrically connected with said electrodes by said leads.

13. Apparatus as claimed in any preceding claim including a holding member for the head of a living creature lying on said surface of said support.

14. Apparatus as claimed in claim 13 wherein the holding member is constructed in the form of an annular inflatable member and the support is also inflatable, the inflatable cavities of the support and the holding member being in communication with one another.

15. Apparatus as claimed in claim 13 or 14 wherein the holding member is united with the support by means of a flexible, foldable strip.

16. Apparatus as claimed in any preceding claim in combination with a device for sensing the pulse rate, or for sensing the peripheral blood pressure, at a finger of a living creature lying on said surface of the support by means of two sensors which are to be applied to opposite sides of the finger, the device comprising a sensor holder of resilient material which is substantially in the form of a flexible tube such that it can be drawn over the finger and on which said sensors are mounted with their finger contacting surfaces exposed towards the inside

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. holder, not that there should be a possibility of sinking in the measuring member holder but simply that there should be the possibility of adequate fixing. Furthermore, the passage of the cable branches 25 and 26 through the measuring-member holder is not absolutely essential, they can be taken out internally to the opening 30 or to the entrance 29 without any disturbance during use. The measuring-member holder in the form of a flexible tube can also be closed at the end, but the opening is comfortable in view of the heat generated by the measuring members and furthermore it enables the measuring-member holder to be pulled appropriately far over the finger tip or the finger to compensate for different thicknesses of finger. In order to integrate this device 21 in the measuring unit combined by the support 1, a connection (not illustrated) particularly a plug-in connection must be provided on the latter. In addition; as Figure 4 shows, a pocket or tray 33 may be provided in the support 1, preferably in a side wall, in which the device 21 can be safely and tidily accommodated when not in use. As illustrated, a roller 34, for example supported on a holder 35, is preferably provided for rolling up the connecting cable 24. The roller 34 may appropriately be equipped with a spring drive on the inside so that the cable 24 has to be pulled out against the force of the spring and rolls up automatically with the force of the spring on being released. WHAT I CLAIM IS:

1. Electrode apparatus for picking up electrical signals from the skin surface of a living creature, the apparatus comprising a support presenting a surface on which the living creature is intended to lie, a plurality of electrodes, some at least of which are designed for picking up heart action voltages produced by the heart action of a living creature lying on said surface, supported on, and fixedly attached to, said surface at predetermined spaced locations covering areas of said surface, the boundaries of such areas being spaced inwardly from the boundaries of said surface, and electrical leads for connecting the electrodes in circuit with diagnostic apparatus or with means for transmitting signals representing measured values to diagnostic apparatus, said leads passing through the support.

of the tube.

17. Apparatus as claimed in claim 16 wherein the sensor holder has the shape of a funnel, the sensors being disposed close to the open, narrow end of the funnel.

18. Apparatus as claimed in claim 16 or 17 wherein the sensor holder comprises a tongue-like holding flap at its finger entrance end.

19. Apparatus as claimed in claim 16, 17 or 18 wherein the sensor holder consists of resilient foamed plastics material.

20. Apparatus as claimed in claim 19 wherein the sensors are sunk into the foamed plastics material.

21. Apparatus as claimed in claim 16, 17, 18, 19 or 20 wherein the support comprises a tray or pocket to receive the pulse rate measuring or blood pressure measuring device.

22. Apparatus as claimed in claim 21 wherein the tray or pocket contains a spring driven roller to wind up the leads of the measuring device.

23. Electrode apparatus substantially as hereinbefore described with reference to, and as shown in, Fig. 1 of the accompanying drawings.

24. Electrode apparatus substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

drawings.

25. Electrode apparatus substantially as hereinbefore described with reference to Figs. 3 and 4 of the accompanying drawings.