Patent Description:
Such electrodes are used for establishing electrical contact between the skin of humans or animals and electrical measuring equipment for measuring or detecting bioelectrical signals caused by physiological processes, such as the heart function. Plotting of curves indicative of this function is called electrocardiography, abbreviated as ECG, and electrodes of this type are therefore often called ECG electrodes.

<CIT> discloses a biomedical electrode using a conductive adhesive gel layer for attaching the electrode to the skin. The conductive adhesive gel layer is covered by an air-permeable protective member and the electrode is provided with a centrally arranged electrical connector for connection to monitoring equipment. The electrode is furthermore provided with a ring-formed reinforcing member arranged on the top of the air-permeable protective member, at the rim of the conductive adhesive gel layer in order to suppress deformation of the electrode and in order to suppress the occurrence of displacement between the protective member and the adhesive gel layer caused by the water absorption and the adhesion of the gel to the clothes or the like.

<CIT>discloses a medical electrode comprising a sensor which is attached to a person's skin. Spaced from the sensor, the electrode is provided with a relief which is also adhered to the person's skin. The electrode is shaped in such a manner between the sensor and the attachment point as to permit and compensate for mutual movements between the sensor and the attachment point, without such movements loading the sensor.

<CIT> discloses a biomedical electrode including a conductive metal layer arranged under a retainer sheet. In the preferred embodiment, the retainer sheet and metal layer are preattached to each other, and the retainer sheet is comprised of a gravure printed, silver/silver chloride treated, polyester film. The polyester film is a dielectric material that can insulate the remainder of the electrode from stray electrical signals that could otherwise be picked up from the surroundings including static charges from nearby clothing, bedding or the like.

<CIT> discloses a medical electrode for contacting the skin, comprising a foam plastic disc which is formed with an aperture, and the part of the disc surrounding the aperture is covered by a cover foil on one side thereof. A sensor strip is placed below the foil in the aperture and is connected to the stripped end of a plastic insulated lead, whose end portion is covered by the cover foil.

<CIT> discloses an ECG electrode which can be placed within the direct path of x-rays during an imaging scan without inducing an x-ray induced erroneous current. The ECG electrode has a support element with a conductive post on one side electrically connected to a conductive plate on the other side. A dissipative anti-static element in or near the ECG electrode dissipates static electricity which forms on the surfaces of the insulating components in the ECG electrode. The dissipative anti-static element may be, for example, a slightly conductive property of the bulk material used to make the insulating material, or a conductive coating added to the insulating material surfaces. The dissipative anti-static element may also be incorporated in the clamp attached to the conductive post.

<CIT> relates to signal monitoring leads with dissipative covers and is described with particular application to electrocardiography. In one aspect, a lead set for transferring an electrical biological signal from an electrode to a monitoring device, includes an electrode connector, a monitor connector, a cable, and an electro-static dissipative cover. The electrode connector is configured to electrically connect to an electrode. The monitor connector is configured to electrically connect to a monitor. The first end of the cable is electrically coupled to the electrode connector and a second end electrically coupled to the monitor connector. The static dissipative cover is configured to cover at least one of the electrode connector or the cable.

<CIT> discloses a well-known type of disc-formed medical electrode having a centred snap connector placed directly over and in direct contact with an electrolyte gel. The centred snap connector projects through an aperture in a foam body. Optionally, a label may be included on the top surface of the foam body. The foam body includes an adhesive backing on its bottom surface. A release liner is adhered to the adhesive backing of the foam body.

However, all the existing prior art electrodes are more or less prone to signal artifacts induced by electrostatic noise and/or signal artifacts caused by mechanical impact on the electrode. Such signal artifacts may be caused by movement of the patient being monitored, movement of clothing, and/or electrostatic charges in the surroundings. These artifacts may complicate visual inspection of the signals by clinicians. In order to reduce this problem, different kinds of software filtering are usually applied to the signals before visual inspection by the clinicians.

Signal artifacts may in particular be problematic in clinical applications such as stress tests, for instance on a bike or running on a treadmill. Misinterpretation of the signals as well as re-recordings due to artefacts in the signal may be a concern. Furthermore, during telemetry monitoring in hospitals, false alarms may be a result of artefacts in the signals. Also during long-term Holter monitoring, that is, ECG monitoring at home doing everyday activities, artefacts in the signals may be a concern.

The object of the present disclosure is to provide a medical electrode having, without the application of any software filtering, an improved signal quality as compared to existing medical electrodes.

In view of this object, a protective disc-formed structure having a lid and an outer rim is arranged at the top side of the plastic foam disc, and the outer rim of the protective disc-formed structure is attached to the medical electrode.

In this way, by attaching the protective disc-formed structure to the medical electrode along the outer rim of the protective disc-formed structure, at least a central part of the medical electrode at the contact medium chamber may be mechanically reinforced by the protective disc-formed structure in such a way that mechanical impact on the sensor strip and/or contact medium in the form of gel disposed in the contact medium chamber may be reduced during application of the electrode on the skin of a patient. Thereby, signal artifacts caused by any kind of touch/direct mechanical impact, such as movement of the patient, surroundings such as clothing, or the electrode itself, may be reduced or eliminated. The already stabilising effect of the weld line may be enhanced by the attachment of the protective disc-formed structure such that a particular strong reinforcement of the medical electrode and in particular the contact medium chamber may be obtained. Deformation of the contact medium chamber could lead to disturbances in the signal.

In an embodiment, the lid of the protective disc-formed structure is made of a plastic material having a tensile modulus being higher than <NUM> GPa and preferably higher than <NUM> GPa (Test method: ASTM-D-<NUM>:<NUM>). Thereby, the contact medium chamber may be even better mechanically reinforced by the protective disc-formed structure.

In a structurally particularly advantageous embodiment, the lid of the protective disc-formed structure forms an inner closed chamber when the protective disc-formed structure is attached to the medical electrode. The closed chamber may form a kind of air-cushion in order to dampen or reduce transfer of mechanical impact to the sensor strip and/or contact medium caused by mechanical impacts on the top of the protective disc-formed structure.

In an embodiment, the outer rim of the protective disc-formed structure is attached to the top side of the plastic foil.

In an embodiment, the outer rim of the protective disc-formed structure is attached to the top side of the plastic foil above or radially outside the weld line surrounding the aperture in the plastic foam disc. Thereby, the already stabilising effect of the weld line may be enhanced by the attachment of the outer rim of the protective disc-formed structure and a particular strong reinforcement of the medical electrode may be obtained. Furthermore, the outer rim of the protective disc-formed structure may be attached to the top side of the plastic foil in one operation in which the plastic foil is also being welded to the plastic foam disc, thereby creating the weld line surrounding the aperture in the plastic foam disc.

In an embodiment, a sponge made from a foam material, such as open pore foam or closed cell foam, is arranged between the lid and the top side of the plastic foam disc. Thereby, mechanical impact on the top of the protective disc-formed structure may be even better dampened in that the sponge may create a cushion effect between the lid of the protective disc-formed structure and the top of the contact medium chamber so that mechanical impact on the sensor strip disposed in the contact medium chamber may be further reduced during application of the electrode on the skin of a patient.

In an embodiment, the sponge is arranged between the lid and the top side of the plastic foam disc in a compressed state. Thereby, a slight pressure may be induced on the sensor area of the contact medium chamber and the cushion effect of the sponge may be further enhanced.

In an embodiment, the sponge in its compressed state has a compressed height being less than <NUM> per cent of an uncompressed height of the sponge before compression and arrangement of the sponge between the lid and the top side of the plastic foam disc. Thereby, the cushion effect of the sponge may be even further enhanced.

In an embodiment, the medical electrode includes an electrostatic shielding covering at least the entire top side of the plastic foam disc, and the electrostatic shielding includes at least an upper dissipative layer and a lower conductive layer. Thereby, the medical electrode may be shielded against electrostatic charges of the surroundings and the signal quality may be improved. By providing an upper dissipative layer, an outer shield is obtained, and by providing a lower conductive layer, any charges are allowed to flow to ground.

In an embodiment, the electrostatic shielding forms a rim area extending from an edge of the plastic foam disc, and, in said rim area, a bottom side of the lower conductive layer of the electrostatic shielding is provided with an electrically conductive and adhesive solid gel layer. Thereby, the lower conductive layer of the electrostatic shielding may be in direct electrical contact with skin of the patient through the electrically conductive and adhesive solid gel layer. Thereby, the lower conductive layer may lead any charges to flow to ground in the form of the skin of the patient.

In an embodiment, the electrostatic shielding is adapted to cover the electric connector. Thereby, also the electric connector may be shielded against electrostatic charges of the surroundings and the signal quality may be further improved. The electric connector is adapted to be electrically connected to not shown monitoring equipment in a well-known way by means of a cable, lead or wire, in that the electric connector has a first snap lock part, for instance a male part, to which a second snap lock part, for instance a female part, of the cable may connect.

A mating connector on a lead/wire and preferably also a first part of the lead/wire may also be covered by the electrostatic shielding. Thereby, the signal quality may be even further improved by reducing electrostatically induced signal disturbances caused at/near the connector and/or wire.

In an embodiment, the electrostatic shielding is provided with at least one flap adapted to be folded about the electric connector and possibly part of a cable connected thereto. Thereby, every side of the electric connector may be shielded against electro-static charges of the surroundings and the signal quality may be even further improved.

In an embodiment, the upper dissipative layer of the electrostatic shielding is oriented polypropylene (OPP), and the lower conductive layer of the electrostatic shielding is preferably formed by electrically conductive ink printed on a lower side of the upper dissipative layer. Preferably, the electrically conductive ink is printed as a grid on a lower side of the upper dissipative layer.

The invention disclosure will now be explained in more detail below by means of examples of embodiments with reference to the very schematic drawing, in which.

In the following, generally, similar elements of different embodiments have been designated by the same reference numerals.

<FIG> illustrate a well-known prior art medical electrode <NUM> including a plastic foam disc <NUM> having a top side <NUM> and a bottom side <NUM>. The plastic foam disc <NUM> may be more or less circular or may have any other suitable form. The electrode <NUM> may typically be of the type used for establishing electrical contact between the skin of humans or animals and electrical measuring equipment when performing electrocardiography. The electrode could for instance be a BlueSensor R available from Ambu (Registered Trademark).

A preferably circular aperture <NUM> extends at a central part of the plastic foam disc <NUM> from the top side <NUM> to the bottom side <NUM> of the plastic foam disc <NUM> and thereby forms a contact medium chamber <NUM>. A plastic foil <NUM> has a top side <NUM> and a bottom side <NUM> and is arranged on the top side <NUM> of the plastic foam disc <NUM>, thereby covering the aperture <NUM> and at least a part of the surrounding plastic foam disc <NUM>. The bottom side <NUM> of the plastic foil <NUM> is welded to the top side <NUM> of the plastic foam disc <NUM> along a weld line <NUM> surrounding the aperture <NUM>. Furthermore, an electric connector <NUM> is mounted on the plastic foil <NUM> eccentrically in relation to the central part of the plastic foam disc <NUM> at which the aperture <NUM> is arranged. As seen, in the illustrated embodiment, the plastic foil <NUM> has a teardrop form with the electric connector <NUM> arranged at a thin end of the teardrop form. The electric connector <NUM> is adapted to be electrically connected to not shown monitoring equipment in a well-known way by means of a cable <NUM> in that the electric connector <NUM> has a first snap lock part <NUM> to which a second snap lock part <NUM> of the cable may connect. The second snap lock part <NUM> and the cable <NUM> is only illustrated in <FIG> and <FIG>. In this embodiment, the first snap lock part <NUM> is a male connector and the second snap lock part <NUM> is a female connector. This female connector part <NUM> on the cable <NUM> may often be referred to as "cable connector". It may actually also be a crocodile clip. An alternative connector can be an "interface plug" is arranged on the male stud on the electrode (or integrated instead of the male stud) and is adapted to receive a banana plug. Alternatively, the cable or wire can be integrated into the electrode, e.g. as in Ambu® BlueSensor QR.

A sensor strip <NUM> is disposed in the contact medium chamber <NUM> and is electrically connected to the electric connector <NUM> by means of an extension <NUM> of the sensor strip <NUM> or possibly by means of a dedicated conductive element. The sensor strip <NUM> may for instance have the form of a metal strip, for instance a silver chloride coated silver strip, a carbon strip, or a sensor area printed by means of conductive ink on a strip. A layer <NUM> of pressure-sensitive adhesive is applied to the bottom side <NUM> of the plastic foam disc <NUM>.

A sponge <NUM> is arranged across the contact medium chamber <NUM>, e.g. by a peripheral edge of the sponge <NUM> being adhered to the bottom side <NUM> of the plastic foam disc <NUM> by means of the layer <NUM> of pressure-sensitive adhesive. The necessary electrical contact between the sensor strip <NUM> and the skin of a person can be established by means of a contact medium <NUM> which has been at least partly absorbed in the sponge <NUM>. The contact medium <NUM> may generally be a paste-like electrolyte. The contact medium <NUM> is typically a conductive (wet) gel. The conductive gel typically comprises ions, such as chloride ions ( CI-) that transfer bioelectric signals from the patient's skin to the sensor strip <NUM>. Preferably, the gel is a NaCl + KCI containing gel. The layer <NUM> of pressure-sensitive adhesive applied to the bottom side <NUM> of the plastic foam disc <NUM> may ensure that the medical electrode <NUM> is securely adhered to the skin of a person during use.

As patients are often to be monitored for long periods of time, e. several days, it is important that the medical electrode <NUM> adds as little to the discomfort of the patient or carrier as possible. This is provided for to a great extent by the use of the plastic foam disc <NUM>, which is a soft and pliable material. The preferred foam plastics for the plastic foam disc <NUM> is PVC foam; however, other materials may be used, such as polyolefines, natural or synthetic rubber, biopolymers, polyesters, polyethers, polyurethanes, polyamides, or copolymers such as ABS or mixtures thereof or laminates comprising one or more of these may further be used. It is also important that the gel-like contact medium <NUM>, which is generally used for establishing good electrical connection between the sensor strip <NUM> and the skin, can be kept intact during the entire period of operation. This means that the walls defining the contact medium chamber <NUM> must be so tight as to allow no considerable diffusion of the constituent components of the contact medium <NUM>.

Although in <FIG>, as explained above, it has been illustrated that the plastic foil <NUM> is welded to the top side <NUM> of the plastic foam disc <NUM> along a weld line <NUM> surrounding the aperture <NUM>, in reality, the weld line <NUM> may be broader than illustrated and may extend to the edge of the contact medium chamber <NUM> as it will be explained in the following. The preferred material for the plastic foil <NUM> which in the case of the Ambu BlueSensor is in blue colour, is polyvinylChloride (PVC); however, other materials may be used, such as polyolefines, natural or synthetic rubber, biopolymers, polyesters, polyethers, polyurethanes, polyamides or copolymers such as ABS or mixtures thereof or laminates comprising one or more of these may also be used.

The prior art medical electrode <NUM> illustrated in <FIG> may be manufactured by placing the various parts in their proper mutual positions between a not shown flat metal substrate and a not shown metal pressing plate, and whereby the pressing plate is subsequently moved so far down towards the substrate that the part of the plastic foam disc <NUM> aligned with the plastic foil <NUM> is somewhat compressed. The substrate and the pressing plate may form a capacitor inserted in a high-frequency circuit (not shown), and heat may be developed between these plates as a consequence of dielectric losses. The heat causes walls of compressed plastic foam cells to fuse partly so that the part of the plastic foam disc <NUM> in question is fixed in the compressed shape. At the same time the plastic foil <NUM> is welded to the plastic foam disc <NUM>. The extension <NUM> of the sensor strip <NUM> extends through the welding formed to the electric connector <NUM>. Other suitable manufacturing methods are, of course, also possible.

The compression of the part of the plastic foam disc <NUM> surrounding the aperture <NUM> causes the aperture to become so shallow that the necessary electrical contact between the sensor strip <NUM> and the skin can easily be established by means of the sponge <NUM>, in which the contact medium <NUM> has been absorbed and which is adhered to the plastic foam disc <NUM> around the aperture <NUM>.

<FIG> illustrate a medical electrode <NUM> according to the present disclosure wherein a protective disc-formed structure <NUM> having a lid <NUM> and an outer rim <NUM> is arranged at the top side <NUM> of the plastic foam disc <NUM>. The outer rim <NUM> of the disc-formed structure is attached to the underlying medical electrode <NUM>, preferably by being attached to the top side <NUM> of the plastic foil <NUM>, and preferably by adhesion, welding or hot melting. Adhesion may for instance by performed by means of sticky double-sided tape <NUM> arranged between the outer rim <NUM> and the top side <NUM> of the plastic foil <NUM>. Thereby, at least a central part of the medical electrode <NUM> at the contact medium chamber <NUM> may be mechanically reinforced by the protective disc-formed structure <NUM> in such a way that mechanical impact on the sensor strip <NUM> disposed in the contact medium chamber <NUM> may be reduced during application of the medical electrode on the skin of a patient. Further, the presence of the lid <NUM> in combination with weld line <NUM> that surrounds the contact medium chamber <NUM> may provide stability against deformation of the contact medium chamber that could induce mechanical artifacts in the biosignals detected by the electrode. Thereby, signal artifacts caused by any kind of mechanical impact, such as movement of the patient, surroundings such as clothing, or the medical electrode itself, may be reduced or eliminated. As a further advantage, the addition of the protective disc-formed structure <NUM> also strengthens the medical electrode <NUM> in such a way that it may be avoided that the contact medium <NUM>, arranged in the contact medium chamber <NUM> and at least partly absorbed in the sponge <NUM>, inadvertently is pressed out of its location when handling the medical electrode.

Preferably, the lid <NUM> of the protective disc-formed structure <NUM> is made of a plastic material having a tensile modulus being higher than <NUM> GPa and preferably higher than <NUM> GPa. The material of the protective disc-formed structure <NUM> may be a combination film in the form of A-PET / LDPE laminate or film or other alternative stiff materials such as PE, PP, ABS, PET or laminates comprising one or more layers thereof. The protective disc-formed structure <NUM> may have a thickness of <NUM>-<NUM>, preferably <NUM>-<NUM>, for instance <NUM>.

As seen, the lid <NUM> of the protective disc-formed structure <NUM> forms an inner closed chamber <NUM> when the protective disc-formed structure <NUM> is attached to the medical electrode <NUM>. In the illustrated embodiment, the lid <NUM> is formed by a top wall <NUM> and a side wall <NUM> connecting the top wall <NUM> and the outer rim <NUM>. The inner closed chamber <NUM> may form a kind of air-cushion in order to prevent or at least reduce transfer of mechanical impact from the top of the protective disc-formed structure <NUM> to the contact medium chamber <NUM> and the sensor strip <NUM>. Such mechanical impact on the contact medium chamber <NUM> could otherwise induce artefacts in the biosignals obtained from the medical electrode.

In the illustrated embodiment, the outer rim <NUM> of the protective disc-formed structure <NUM> is attached to the top side <NUM> of the plastic foil <NUM> above the weld line <NUM> surrounding the aperture <NUM> in the plastic foam disc <NUM>. However, the outer rim <NUM> of the protective disc-formed structure <NUM> may just as well be attached to the top side <NUM> of the plastic foil <NUM> slightly radially outside the weld line <NUM> surrounding the aperture <NUM> in the plastic foam disc <NUM>. These embodiments are preferred due to enhanced stability of the medical electrode <NUM> against general deforming. The already stabilising effect of the weld line <NUM> may be enhanced by the attachment of the outer rim <NUM> of the protective disc-formed structure <NUM> such that a synergistic effect may be obtained and thereby a particular strong reinforcement of the contact medium chamber <NUM> and the medical electrode <NUM> may be obtained against mechanical impact. In the case that the protective disc-formed structure <NUM> is attached to the plastic foil <NUM> by means of welding, the welding process may be performed in one welding step whereby the three components, the protective disc-formed structure <NUM>, the plastic foil <NUM> and the plastic foam disc <NUM> are connected together.

As further illustrated in <FIG>, a sponge <NUM> made from a foam material, such as open pore foam or closed cell foam, may be arranged between the lid <NUM> and the top side <NUM> of the plastic foam disc <NUM>. Furthermore, in the illustrated embodiment, the sponge <NUM> is arranged between the lid <NUM> and the top side <NUM> of the plastic foil <NUM>. Thereby, mechanical impact on the top of the protective disc-formed structure <NUM> may be even better dampened in that the sponge <NUM> may create a cushion effect between the lid <NUM> of the protective disc-formed structure <NUM> and the top of the contact medium chamber <NUM> so that mechanical impact on the sensor strip <NUM> disposed in the contact medium chamber <NUM> may be further reduced during application of the medical electrode <NUM> on the skin of a patient.

The sponge <NUM> is arranged between the lid <NUM> and the top side of the plastic foam disc <NUM> in a compressed state. Thereby, a slight pressure may be induced on a sensor area of the contact medium chamber <NUM> and the cushion effect of the sponge <NUM> may be further enhanced. Preferably, the sponge <NUM> in its compressed state has a compressed height being less than <NUM> per cent of an uncompressed height of the sponge <NUM> before compression and arrangement of the sponge <NUM> between the lid <NUM> and the top side <NUM> of the plastic foam disc <NUM>.

The sponge <NUM> may for instance be formed of a polyurethane or polyether foam, such as polyurethane <NUM> commercially available from Bramming Plast-Industri A/S, Denmark. The thickness may for instance be more than <NUM> for a lid <NUM> with a height of about <NUM>, the density may for instance be about <NUM>/m<NUM>(ISO <NUM>), a compression hardness may for instance be about <NUM> kPa (ISO <NUM> (<NUM>%)) and a tensile strength may for instance be about <NUM> kPa (ISO <NUM>).

<FIG> illustrate a medical electrode <NUM> according to the present disclosure wherein the medical electrode <NUM> includes an electrostatic shielding <NUM> in the form of a sheet covering the entire medical electrode <NUM>. The electrostatic shielding <NUM> includes at least an upper dissipative layer <NUM> and a lower conductive layer <NUM>. Thereby, the medical electrode <NUM> may be shielded against electrostatic charges of the surroundings and the signal quality may be improved. By providing an upper dissipative layer <NUM> , an outer shield is obtained, and by providing a lower conductive layer <NUM>, any charges are allowed to flow to ground. A not shown adhesive material, such as acrylic, silicone etc., may be attached to the lower side of the lower conductive layer <NUM> in order to adhere the electrostatic shielding <NUM> to the medical electrode <NUM>. In the embodiment of <FIG>, the medical electrode <NUM> has not been provided with a protective disc-formed structure <NUM> as illustrated in the embodiment of <FIG>.

The embodiment disclosed in <FIG> is defined as a medical electrode <NUM> including a plastic foam disc <NUM> having a top side <NUM> and a bottom side <NUM>. Furthermore, an aperture <NUM> extends at a central part of the plastic foam disc from the top side to the bottom side and thereby forms a contact medium chamber <NUM>. A plastic foil <NUM> has a top side <NUM> and a bottom side <NUM> and is arranged on the top side of the plastic foam disc, thereby covering the aperture and at least a part of the surrounding plastic foam disc. The bottom side of the plastic foil is welded to the top side of the plastic foam disc along a weld line <NUM> surrounding the aperture. An electric connector <NUM> is mounted on the plastic foil eccentrically in relation to the central part of the plastic foam disc. The electric connector is adapted to be electrically connected to monitoring equipment. A sensor strip <NUM> is disposed in the contact medium chamber and is electrically connected to the electric connector. A layer of pressure-sensitive adhesive <NUM> is applied to the bottom side of the plastic foam disc. Furthermore, the medical electrode includes an electrostatic shielding <NUM> covering at least the entire top side of the plastic foam disc, and the electrostatic shielding includes at least an upper dissipative layer <NUM> and a lower conductive layer <NUM>. Preferably, in this embodiment, the upper dissipative layer of the electrostatic shielding is oriented polypropylene (OPP), and preferably, the lower conductive layer of the electrostatic shielding is formed by electrically conductive ink printed as a grid on a lower side of the upper dissipative layer.

As seen, the electrostatic shielding <NUM> forms a rim area <NUM> extending from an edge <NUM> of the plastic foam disc <NUM>, and in said rim area <NUM>, a bottom side <NUM> of the lower conductive layer <NUM> of the electrostatic shielding <NUM> is provided with an electrically conductive and adhesive solid gel layer <NUM>. Thereby, the lower conductive layer <NUM> of the electrostatic shielding <NUM> may be in direct electrical contact with skin of the patient through the electrically conductive and adhesive solid gel layer <NUM>. Thereby, the lower conductive layer <NUM> may lead any charges to flow to the skin of the patient, thereby acting as ground connection. The electrically conductive and adhesive solid gel layer <NUM> may for instance be of the type AG625 SENSING GEL commercially available from Axelgaard Manufacturing CO.

<FIG> illustrates an embodiment of the medical electrode <NUM> according to the present disclosure corresponding to the embodiment illustrated in <FIG>, however, in the embodiment of <FIG>, the medical electrode <NUM> includes an electrostatic shielding <NUM> covering the entire medical electrode <NUM> including a protective disc-formed structure <NUM> including optionally a sponge <NUM> as described above. The protective disc-formed structure <NUM> provides further distance between the remaining part of the medical electrode <NUM> and the electrostatic shielding <NUM> which under certain circumstances may improve the electrostatic shielding of the medical electrode <NUM>. It is noted, however, that in an alternative embodiment, the protective disc-formed structure <NUM> including the sponge <NUM> or without the sponge <NUM> may be arranged on the top side of the electrostatic shielding <NUM> so that the protective disc-formed structure <NUM> and the sponge <NUM> are not covered by the electrostatic shielding <NUM>. This may not alter the electrostatic shielding function provided by the electrostatic shielding <NUM>, but possibly, it may facilitate production of the medical electrode <NUM>.

As seen in the embodiments of <FIG> and <FIG>, the electrostatic shielding <NUM> may also be adapted to cover the electric connector <NUM>. Thereby, also the electric connector <NUM> may be shielded against electrostatic charges of the surroundings and the signal quality may be further improved. As mentioned above, the electric connector <NUM> is adapted to be electrically connected to not shown monitoring equipment in a well-known way by means of a cable <NUM>. The electric connector <NUM> has a first snap lock part <NUM> to which a second snap lock part <NUM> of the cable may connect. According to the embodiments of <FIG> and <FIG>, both the first snap lock part <NUM> and the second snap lock part <NUM> and at least a part of the cable <NUM> may be covered by the electrostatic shielding <NUM>. Preferably, the cable <NUM> is a shielded wire, such as a coax wire.

<FIG> and <FIG> illustrate two different embodiments in which the sheet forming the electrostatic shielding <NUM> is provided with two flaps <NUM> adapted to be folded about the electric connector <NUM>. Each flaps <NUM> is arranged bendable in relation to a midportion <NUM> of the electrostatic shielding <NUM>. In <FIG> optional bending lines <NUM> between the midportion <NUM> and the respective flaps <NUM> are illustrated. Alternatively, only one flap may be provided which may be bent one or two times in order to appropriately cover all sides of the electric connector <NUM>. For instance, the one or two flaps <NUM> adapted to be folded about the electric connector <NUM> may be provided with one or more not shown separate release liner(s) to be removed before folding the flap or flaps about the electric connector <NUM>. The foldable electrostatic shielding may be applicable to cover the cable <NUM> and connector <NUM> irrespective of the connector type employed. Different connector types are discussed above. If the cable <NUM> is pre-attached to the medical electrode (no connector), then the electrostatic shielding <NUM> may be bent around the cable at the factory.

Preferably, generally, the upper dissipative layer <NUM> of the electrostatic shielding <NUM> is oriented polypropylene (OPP), and preferably, the lower conductive layer <NUM> of the electrostatic shielding is formed by electrically conductive ink printed on a lower side of the upper dissipative layer. However, other suitable materials may also be employed for the upper dissipative layer <NUM> of the electrostatic shielding, such as for instance polypropylene in general or polyethylene in general. Preferably, the electrically conductive ink is printed as a grid on the lower side of the upper dissipative layer. Such electrostatic shielding is commercially available, for instance in the form of "ESD Anti-static Grid Tapes" from Conrad Electronic SE, Germany. The upper dissipative layer <NUM> of the electrostatic shielding <NUM> may for instance have a surface resistance of <NUM><NUM> Ohm to <NUM><NUM> Ohm, such as about <NUM><NUM> Ohm, and the lower conductive layer <NUM> may for instance have a resistivity of about <NUM> Ohm·m.

In order to demonstrate the effect of the different embodiments of the medical electrode <NUM> according to the present disclosure, a number of tests have been performed as described in the following.

<FIG> illustrates the test setup, whereby for each test, prototype medical electrodes 38A, 38B according to the present disclosure as well as reference prior art medical electrodes 39A, 39B and a single neutral (ground) medical electrode <NUM> are placed as illustrated in the figure on a torso of a test person. In each case, the reference prior art medical electrodes 39A, 39B are of the type Ambu BlueSensor. The ECG recordings were obtained using AMEDTEC ECGpro CardioPart and their standard software adapted to be able to record bipolar signals. No pre-defined software filters were applied during recording. The signals were recorded with two sets of medical electrodes, so the prototype signal and the reference signal could be recorded simultaneously. Importantly, the amplitudes of the ECG signals were similar on both leads. If not the case, the prototypes were replaced and repositioned until the amplitudes were substantially similar as on the ECG signal illustrated in <FIG>.

According to the test protocol, the following activities were performed simultaneously on the four test electrodes:.

A selection of the test results are illustrated in <FIG> as follows. In each test performed, it has been seen that the signal of the prototype medical electrodes 38A, 38B represents a substantive reduction of the signal artefacts which are present in the signal of the reference medical electrodes 39A, 39B.

<FIG> illustrates ECG signals for prototype medical electrodes 38A, 38B provided with an electrostatic shielding <NUM> (similar to medical electrode shown in <FIG>) and reference medical electrodes 39A, 39B, respectively, when shaking a shirt of a test person in order to induce electrostatic disturbances.

<FIG> illustrates ECG signals for prototype medical electrodes 38A, 38B provided with an electrostatic shielding <NUM> (similar to medical electrode shown in <FIG>) and reference medical electrodes 39A, 39B, respectively, when tapping on top of the electrodes.

<FIG> illustrates ECG signals for prototype medical electrodes 38A, 38B provided with a protective disc-formed structure <NUM> enclosing a sponge <NUM> (similar to medical electrode shown in <FIG>) and reference medical electrodes 39A, 39B, respectively, when tapping on top of the electrodes.

<FIG> illustrates ECG signals for prototype medical electrodes 38A, 38B provided with a protective disc-formed structure <NUM> (similar to medical electrode shown in <FIG>, but without sponge <NUM>) and reference medical electrodes 39A, 39B, respectively, when tapping on top of the electrodes. In is noted that in the diagram of <FIG>, the ECG signal for the prototype medical electrodes 38A, 38B is shown below the ECG signal for the reference medical electrodes 39A, 39B, as opposed to the corresponding diagrams illustrated in the other figures.

<FIG> illustrates ECG signals for prototype medical electrodes 38A, 38B provided with an electrostatic shielding <NUM> (similar to medical electrode shown in <FIG>, but without sponge <NUM>) and a protective disc-formed structure <NUM>, and reference medical electrodes 39A, 39B, respectively, when shaking a shirt of a test person.

<FIG> illustrates ECG signals for prototype medical electrodes 38A, 38B provided with an electrostatic shielding <NUM> and a protective disc-formed structure <NUM> enclosing a sponge <NUM> (similar to medical electrode shown in <FIG>), and reference medical electrodes 39A, 39B, respectively, when shaking a shirt of a test person.

Claim 1:
A medical electrode (<NUM>) including a plastic foam disc (<NUM>) having a top side (<NUM>) and a bottom side (<NUM>), an aperture (<NUM>) extending at a central part of the plastic foam disc (<NUM>) from the top side (<NUM>) to the bottom side (<NUM>) and thereby forming a contact medium chamber (<NUM>), a plastic foil (<NUM>) having a top side (<NUM>) and a bottom side (<NUM>) and being arranged on the top side (<NUM>) of the plastic foam disc (<NUM>), thereby covering the aperture (<NUM>) and at least a part of the surrounding plastic foam disc (<NUM>), the plastic foil (<NUM>) being welded to the plastic foam disc (<NUM>) along a weld line (<NUM>) surrounding the aperture (<NUM>), an electric connector (<NUM>) being mounted on the plastic foil (<NUM>) eccentrically in relation to the central part of the plastic foam disc (<NUM>), the electric connector (<NUM>) being adapted to be electrically connected to monitoring equipment, a sensor strip (<NUM>) disposed in the contact medium chamber (<NUM>) and electrically connected to the electric connector (<NUM>), and a layer of pressure-sensitive adhesive (<NUM>) applied to the bottom side (<NUM>) of the plastic foam disc (<NUM>), wherein a protective disc-formed structure (<NUM>) has a lid (<NUM>) and an outer rim (<NUM>) and is arranged at the top side (<NUM>) of the plastic foam disc (<NUM>), and wherein the outer rim (<NUM>) of the protective disc-formed structure (<NUM>) is attached to the medical electrode (<NUM>).