Medical electrodes and their systems

Abstract

The present invention is a medical electrode comprising: an electrolyte; an absorbent material in contact with the electrolyte, the absorbent material comprising a plurality of strands, each strand being infused with the electrolyte; a pressing device in contact with the absorbent material, the pressing device comprising a plurality of protrusions for pushing the strands of absorbent material through the stratum corneum of a target skin area of ​​a patient; and a conductive device positioned adjacent to the pressing device and in contact with the absorbent material. The present medical electrode system reduces skin impedance at the site of electrode placement and generates low baseline noise, thereby enabling accurate measurement of small or weak signals.

Description

Technical Field

[0001] The present invention relates to a medical electrode and a system thereof. The medical electrode reduces skin impedance at the electrode placement site without exfoliating the skin and generates low baseline noise, thereby enabling accurate measurement of small or weak signals, including but not limited to fetal electrocardiogram (ECG). Background Art

[0002] Medical electrodes are used to detect electrical potentials on the skin surface for various health diagnostics. There is market demand for medical electrodes that can effectively sense and detect small or weak electrical signals. In fetal monitoring technology, fetal ECG is used to monitor fetal heart rate. Surface electrodes with either wet or solid gel are used to pick up this signal. However, acquiring fetal ECG signals from the mother's abdomen is challenging because the amplitude of the fetal ECG ranges from 5 to 20 microvolts. Furthermore, this signal is buried within a complex network of maternal ECG signals, signals generated by uterine activity due to maternal contractions, and ambient noise. The high electrical impedance of the stratum corneum—the outermost layer of the skin—makes picking up this small signal even more challenging. The stratum corneum suppresses the fetal ECG signal and causes noise at the electrode-skin interface. When measuring fetal ECG, electrodes are placed on the patient's abdomen. To reduce skin impedance at the electrode placement site, the stratum corneum is exfoliated using mild abrasive paper tape. Prior art electrodes, such as those used in the Monica electronic fetal monitor, have electrodes with a fixed gel area that are available in a range of sizes to reduce skin-related impedance and noise signals to acceptable levels, with each size requiring a minimum number of exfoliation strokes with an abrasive material. However, this approach is skill-dependent and often requires multiple attempts, which can cause patient discomfort and leave scars. Therefore, there is a need for electrodes that can generate low baseline noise and reduce skin-induced impedance to detect small or weak signals without requiring exfoliation of the skin at the site where the electrode contacts the skin.

[0003] Another prior art electrode from Aspect Medical Systems uses tines to separate the outermost layers of the skin and keep them separated. When the tines are pressed, a gel electrolyte contained in the sponge is depressed, and this gel electrolyte seeps into the channels created by the tines. However, this approach is limited because the action of pressing on the tines and their attached pads results in an uneven distribution of the gel and the formation of air pockets between the skin-electrode interface and the pads. The sponge includes multiple cells that hold the electrolyte gel. However, some of the sponge cells contain air. When the sponge is depressed, the air is squeezed out along with the gel, causing bubbles to form in the electrode system, resulting in uneven electrolyte distribution and high baseline noise. Therefore, there is a need for an electrode that evenly distributes the electrolyte without generating bubbles when pressure is applied.

[0004] In addition, the system is particularly ineffective when the electrodes are placed on areas of skin that lack bone structure underneath, such as the skin of the abdomen. Pressing the tines into such skin through the sponge results in poor separation of the skin. In addition, cavitation results in high electrical noise that masks small or weak signals, including but not limited to, fetal ECG. Therefore, the above system will be particularly ineffective for fetal monitoring because the electrodes will be placed on the mother's abdominal skin. In addition, since the mother is not under anesthesia, multiple presses trying to get the electrodes to separate the skin to measure small fetal signals make her feel uncomfortable. Therefore, there is a need for electrodes that can measure signals on any part of the body, especially on parts that lack bone structure underneath the skin.

[0005] Since commercially available electrodes are expensive, low-cost electrodes are also needed.

[0006] Therefore, there is a need for a low-cost medical electrode that effectively reduces skin impedance at the electrode-skin interface, has low baseline noise, enables uniform electrolyte distribution without air bubbles, can be placed on any part of the body, and avoids skin exfoliation before electrode placement, thereby reducing patient discomfort during electrode placement. Summary of the Invention

[0007] In one embodiment, the present invention is a medical electrode comprising: an electrolyte; an absorbent material in contact with the electrolyte, the absorbent material comprising a plurality of strands such that each strand is infused with the electrolyte; a pressing device in contact with the absorbent material, the pressing device comprising a plurality of protrusions for pushing the strands of absorbent material through the stratum corneum of a target skin area of ​​a patient; a conductive device positioned adjacent to the pressing device and in contact with the absorbent material, wherein each electrolyte-infused strand of the absorbent material serves as a conductive path from an entry site in the stratum corneum to the conductive device; and a support device for supporting the electrode and maintaining the electrode in contact with the target skin area of ​​the patient.

[0008] In one embodiment, the present invention is a medical electrode system comprising at least one electrode connected to a flexible base that is removably engageable with a measurement device.

[0009] In one embodiment, the present invention is a method of using a medical electrode or medical electrode system, comprising: placing the electrode directly on a target skin area of ​​a patient; pressing the electrode into the skin to push electrolyte-infused strands of absorbent material through the stratum corneum; and displaying a biopotential signal value detected by the electrode on a measuring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Reference will be made to embodiments of the present invention, examples of which may be shown in the accompanying drawings. These figures are intended to be illustrative and non-restrictive. Although the present invention has been generally described in the context of these embodiments, it should be understood that this is not intended to limit the scope of the invention to these specific embodiments.

[0011] Figure 1A :Embodiments of the medical electrode of the present invention

[0012] Figure 1B 、 Figure 1C 、 Figure 1D : Depicts the area of ​​skin that is pressed into the target Figure 1A Medical electrodes

[0013] Figure 1E :Describes the embodiment as a multi-electrode system DETAILED DESCRIPTION

[0014] The present invention aims to solve the above-mentioned technical and economic disadvantages by providing a medical electrode, which includes: an electrolyte; an absorbent material in contact with the electrolyte, the absorbent material including a plurality of strands, such that each strand is infused with the electrolyte; a pressing device in contact with the absorbent material, the pressing device including a plurality of protrusions for pushing the strands of the absorbent material through the stratum corneum of a target skin area of ​​a patient; a conductive device located near the pressing device, the conductive device in contact with the absorbent material, wherein each strand of the absorbent material infused with the electrolyte serves as a conductive path from an entry site in the stratum corneum to the conductive device; and a supporting device for supporting the electrode and maintaining the electrode in contact with the target skin area of ​​the patient.

[0015] When applying pressure via the pressing device, this electrode produces micro-perforations in the topmost dead skin layer (stratum corneum) of the skin. The pressing action causes the gauze strands to be pushed into these perforations. In addition, because the gauze is thin and easily penetrates the skin and sticks to the entry site, it is necessary to apply minimum pressure. The strands pushed into these perforations also eliminate the need for the preparatory exfoliation step at the position where the electrode is placed. The strands injected with gel contact the more conductive layers of the skin below the stratum corneum. The strands injected with gel form a conductive path between the entry site of the stratum corneum and the conductive device of this electrode. Because gel is injected into the gauze strands, it can not be unevenly distributed or have bubbles that interfere with signal transmission. In this way, this electrode makes it possible to reduce skin impedance when not exfoliating the skin, and generates low baseline noise, thereby making it accurate to obtain the weak signals including but not limited to fetal ECG.

[0016] The electrolyte gel in contact with the absorbent material is an electrolytic medium that allows ion exchange between the skin surface and the conductive device. The electrolyte is the medium through which the biopotential measurement is performed. In one embodiment, the electrolyte gel is liquid and slightly sticky or viscous because it is an alginate-based, highly fluid and skin-friendly composition. The liquid nature and viscosity ensure that the electrolyte is completely absorbed by the gauze and allows the electrolyte to spread evenly when pressure is applied, thereby avoiding the formation of bubbles.

[0017] In one embodiment of the medical electrode, the absorbent material comprises a plurality of strands in the form of a network, preferably in a gauze structure. In a preferred embodiment of the medical electrode, the absorbent material is cotton fiber. In the prior art, a sponge is an absorbent material used in medical electrodes, and the sponge comprises a plurality of cells that hold electrolyte gel. When the sponge is pressed, the gel in the cells is squeezed out. However, the electrolyte distribution is often uneven because some sponge cells have trapped air and bubbles are introduced into the system. These bubbles should be avoided because they cause high baseline noise. In contrast, the present invention uses cotton fibers arranged in a gauze structure. The electrolyte gel is absorbed into the individual strands of the gauze, and the electrolyte gel is not squeezed out when the strands are pressed, and the cotton strands themselves become conductive paths.

[0018] In one embodiment of the medical electrode, the compression mechanism is a plastic microbristle structure in contact with multiple strands of absorbent material. In another embodiment, the compression mechanism has an additional mechanism on the top surface of the electrode, which is the surface facing away from the target skin area, to help apply pressure to the electrode. The additional mechanism is an external mechanical or electromechanical device that applies pressure to the electrode. Due to physical, electrical, or chemical properties, the additional mechanism applies a certain range of pressure for a specific amount of time. In one embodiment, the additional mechanism is a bubble on the top of the electrode, which contains a standardized amount of air. A specific amount / range of pressure needs to be applied to cause the bubble to burst. The internally built-up pressure is evenly applied to the bottom surface of the bubble, which is aligned with the compression mechanism on the top surface of the medical electrode, which is the surface facing away from the skin, until the bubble bursts. In another embodiment, the additional mechanism is a plastic disk designed to evenly distribute the pressure until it bursts once a specific amount of pressure is reached.

[0019] In one embodiment of the medical electrode, the conductive device is adjacent to the pressing device. In this context, the term adjacent includes the conductive device being placed near, next to, to the side, on top of, or offset from the pressing device. In one embodiment of the medical electrode, the conductive device is a plastic substrate coated with a conductive metal layer on the surface in contact with the absorbent material, the surface facing the target skin area. In one embodiment of the medical electrode, the conductive metal layer is silver / silver chloride. In one embodiment of the medical electrode, the plastic substrate is electrically attached to a flexible printed circuit board. In one embodiment, the conductive device has a stainless steel component on the top surface that docks with / locks into a standard ECG cable connector to form a connection with any measuring device including but not limited to the following devices: fetal ECG equipment or adult ECG equipment, neural signal measuring equipment (e.g., EEG), etc. The stainless steel components include but are not limited to studs, wiring, alligator clip connectors, banana stud connectors, or universal snap and tab connectors.

[0020] In one embodiment, the medical electrodes are connected to a measurement device for measuring and recording biopotential signals detected by the electrodes. The electrodes can be used to measure any biopotential signal, including but not limited to fetal and adult ECG measurements, neural signal measurements, and the like. The present invention is specifically designed to detect and measure small or weak signals passing through the skin because it reduces skin impedance without requiring exfoliation of the skin at the electrode contact site and produces low baseline noise at the electrode's entry site.

[0021] In one embodiment, a support device is used to support the electrode and maintain contact between the electrode and the patient's target skin area. In one embodiment, the support device includes two adhesive tapes, a backing tape on which the electrode components are assembled, and a foam-based pressure-sensitive adhesive for adhering the assembled electrode to the patient's skin. In another embodiment, the support device further includes a cover, which is a sheet, film, or membrane with liquid-resistant properties on the top surface of the electrode, the top surface facing away from the patient's skin.

[0022] In one embodiment, the medical electrode comprises a medical electrode system comprising at least one electrode connected to a flexible base removably engageable with a measurement device. The at least one electrode system comprises more than one electrode connected to the flexible base to create a multi-electrode system, the multi-electrode system being connected to the measurement device.

[0023] In one embodiment, it is a method of using a medical electrode or a medical electrode system including more than one electrode, the method comprising: placing the electrode directly on a target skin area of ​​a patient; pressing the electrode into the skin to push an electrolyte-infused strand of absorbent material through the stratum corneum; and displaying a biopotential signal value detected by the electrode on a measuring device.

[0024] Figure 1A An embodiment of a medical electrode of the present invention is shown. The figure depicts a medical electrode (100) in its disassembled form, comprising: a soft cotton (8) in a single or multi-layered gauze or gauze-like structure impregnated with an electrolyte (6); a pressing device (7) in contact with the cotton gauze (8) (in assembled form) for pressing the strands of gauze into the skin at multiple locations; and a conductive device (3). The pressing device (7) in this embodiment comprises a plastic micro-bristle structure with vertical plastic bristles. The strands of gauze (8) form an electrical path (9) between the entry site (9) into the stratum corneum (10) and the conductive device (3). Figure 1C The gauze (8), the conductive device (3) and the pressing device (7) are assembled on a backing tape (1) which is encapsulated in a foam-based pressure-sensitive adhesive (2). The cavity (5) in the pressure-sensitive adhesive is shaped to concentrate the gauze strands at the junction with the conductive device (3). In this embodiment, the conductive device (3) is offset from the pressing device (7) so that pressure is applied directly to the gauze (8).

[0025] The assembly of the electrodes involves placing the conductive device (3) on the adhesive side of the backing tape (1), the adhesive side facing the patient's skin. A pressing device (7) with micro-bristles is attached to the adhesive side away from the conductive device (3), with the bristles pointing to the skin side. This structure is now assembled into a cavity (5) in a foam-based pressure-sensitive adhesive (2), with the adhesive side of the pressure-sensitive adhesive facing the skin. The cavity is closed by the backing tape, so the system is closed from the top side, and the surface is not facing the skin. Gauze (8) is placed in the cavity (5) to occupy the remaining volume of the cavity, and an electrolyte gel (6) is added. The gauze absorbs the electrolyte gel. The gel is an electrolytic medium that allows ion exchange between the skin surface and the conductive device coated with silver / silver chloride. The electrolyte is the medium through which biopotential measurement is performed.

[0026] Figure 1B 、 Figure 1C and Figure 1D Depicts the area of ​​skin that is pressed into the target Figure 1A The plastic bristles of the pressing device (7) push the strands of absorbent material (8) into the stratum corneum (10) at the entry site (9). Figure 1DThe following is shown: pressure is applied to the pressing means (arrows depict the direction of pressure) to push the bristles into the stratum corneum (10), thereby pushing the electrolyte-infused strands of absorbent material into the stratum corneum (10). The electrode has a stainless steel component (4) on the top surface that docks / locks into a standard ECG cable connector to form a connection with any measurement device. The electrode in this embodiment has additional means (11) on the top surface to help apply pressure to the electrode.

[0027] Figure 1E An embodiment as a multi-electrode system is depicted. In this embodiment, the multi-electrode patch includes six electrodes. The electrodes are connected to a flexible base for removably engaging with a monitoring device to detect maternal electrophysiological signals and / or fetal electrophysiological signals from the electrodes. The flexible base in this embodiment includes a flexible substrate (12), a plastic unit (13), and a pressure-sensitive adhesive foam ring (15) for attaching the base of the multi-electrode patch to the patient's skin. The module has a mechanical device for removably mechanically engaging with the monitoring device, and an electrical connection unit (14) for forming an electrical connection from the electrodes to a readout device. Engaging the patch with the monitoring device includes both a mechanical module unit and an electrical module unit.

[0028] The following experimental examples are illustrative of the present invention, but not intended to limit the scope of the present invention:

[0029] Worked Example 1

[0030] The noise characteristic of electrode of the present invention is compared with the noise characteristic of prior art electrode.This electrode comprises the absorbent material as cotton gauze, and prior art electrode comprises the system based on sponge.Two electrodes are applied to different positions at a distance of 6cm from each other on the abdomen.Use 3M solid gel electrode to measure the noise at these positions, and find that these noises are equivalent.Before using sponge electrode or gauze electrode, these values ​​were used as the baseline of noise level.

[0031] The study sampled 40 subjects of varying ages, genders, and skin types. The results from the five scans are shown in the table below. The noise detected by the cotton gauze electrodes was at least 3 times lower than that detected by the sponge-based electrodes, with subject 2 showing a 20-fold reduction in noise.

[0032]

[0033] Thus, the present invention includes a low-cost medical electrode that effectively reduces skin impedance at the electrode-skin interface, has a low baseline noise signal, avoids exfoliation of the skin prior to electrode placement, enables even distribution of electrolytes without air bubbles, can be placed anywhere on the body, and reduces patient discomfort during electrode placement.

[0034] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A medical electrode, comprising: electrolytes; an absorbent material in contact with the electrolyte, the absorbent material comprising a plurality of strands in a gauze-like structure such that each strand of the absorbent material in the gauze-like structure is impregnated with the electrolyte; a pressing device in contact with the gauze-like structure of the absorbent material, the pressing device comprising a plurality of protrusions for urging the strands of the absorbent material through the stratum corneum of a target skin area of ​​a patient; a conductive means positioned adjacent to the compression means, the conductive means in contact with the absorbent material, wherein each electrolyte-infused strand of the absorbent material serves as a conductive pathway from an entry site in the stratum corneum to the conductive means; as well as A support device is used to support the electrode and keep the electrode in contact with the target skin area of ​​the patient.

2. The medical electrode according to claim 1, wherein The absorbent material is cotton fiber.

3. The medical electrode according to claim 1, wherein The conductive device is a plastic substrate coated with a conductive metal layer on the surface facing the target skin area in contact with the absorbent material.

4. The medical electrode according to claim 3, wherein The conductive metal layer is silver / silver chloride.

5. The medical electrode according to claim 3, wherein The plastic substrate is connected to a flexible printed circuit board.

6. The medical electrode according to claim 1, wherein The compression means has further means on the top surface of the electrode to help apply pressure to the electrode, the top surface being the surface facing away from the target skin area.

7. The medical electrode according to claim 1, connected to a measuring device for measuring and recording biopotential signals detected by the electrode.

8. A medical electrode system comprising at least one electrode according to claim 1 connected to a flexible base removably engageable with a measuring device.

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