JP6749773B2 - Moisture sensor - Google Patents

Description

The present invention relates to the structure of a moisture sensor that detects blood or the like in a medical field.

A device for detecting moisture is used in the medical field. This device is typically used in the field of artificial dialysis treatment to detect the presence or absence of blood leakage due to needle removal. Accidents of blood leakage during artificial dialysis must be reliably prevented, but there is a limit to the method of relying on human attention (for example, a nurse's patrol). BACKGROUND ART Conventionally, there has been proposed a water detection device capable of accurately detecting blood leakage during artificial dialysis (see Patent Document 1).

FIG. 5 is a schematic diagram of a conventional moisture detection device used for artificial dialysis treatment.

As shown in the figure, the moisture sensor 2 used in the moisture detector 1 includes a water absorbing material 5. The water absorbent material 5 has an overlay 3 and an underlay 4 that are electrically insulating in a dry state. The upper layer 3 and the lower layer 4 are water absorbent. An electrode 7 including an electric resistance element 6 is sandwiched between the underlay 4 and the overlay 3. The resistance value of the electric resistance element 6 is set to, for example, about 20 kΩ. When blood leaks due to a needle removal or the like during dialysis treatment, the electrodes 7 are electrically connected via blood. That is, the conductivity between the electrodes 7 is increased, and the resistance value is set to suddenly drop to several kΩ. Due to this decrease in resistance value, the current flowing between the electrodes 7 increases, and this is sent as a signal to the notification device S via the connector C. The notification device S that has received this signal emits an alarm sound or turns on the LED. The conventional moisture sensor 2 reliably detects the leakage of blood due to the removal of the needle or the like in this manner, and the notification device S notifies the fact.

FIG. 6 is a perspective view showing a usage state of a conventional moisture detecting device.

As shown in the figure, the moisture sensor 2 is laid under the forearm of the patient undergoing artificial dialysis and in a range capable of receiving the blood leaking from the arm of the patient. However, when the moisture sensor 2 is used in the state shown in the figure, the notification device S cannot notify the leakage of blood until the leaked blood reaches the moisture sensor 2 along the forearm of the patient. For this reason, a large amount of blood may leak from the patient's body before the nurse or the like notices the blood leak by the notification of the notification device S. Further, the dialysis needle is not always pierced into the patient's forearm during artificial dialysis treatment, and may be pierced into the blood vessel of the patient's neck or groin, for example. In this case, it is difficult to properly arrange the moisture sensor 2 and it may be difficult to detect blood leakage.

FIG. 7: is a perspective view which shows the use condition of the conventional improved moisture detection apparatus.

In order to eliminate the above-mentioned inconvenience, the applicant can improve the shape of the moisture sensor as shown in FIG. 7 so that the moisture sensor can be placed at any part of the body, thereby preventing blood leakage during artificial dialysis. A moisture sensor 2 that can be discovered early was proposed (see Patent Documents 2 and 3).

JP2012-196293A JP, 2005-167697, A Utility model registration No. 3190733

However, the moisture sensor 2 disclosed in Patent Documents 2 and 3 is attached along the arm of a patient, and the work is not necessarily easy for the patient himself or a nurse. It was Therefore, it may take a long time to attach the moisture sensor 2, or in some cases, the moisture sensor 2 may not be placed at an appropriate position on the patient's arm or a required site.

Therefore, an object of the present invention is to provide a compact moisture sensor that can be quickly and accurately attached to any part of the body and that can detect blood leakage during artificial dialysis at an early stage.

The inventor of the present application has found that the place where blood leakage occurs during artificial dialysis is the part where the dialysis needle is punctured, so that it does not interfere with the puncture procedure and only the vicinity of the part is reliably surrounded by the moisture sensor. It was thought that the above objective could be achieved if it could be achieved.

(1) In order to achieve the above object, the moisture sensor according to the present invention,
Adhesive to a first annular sheet having water absorption and having an adhesive on the lower surface, and an electrically conductive adhesive showing insulation on drying and electrical conductivity on absorbing water on the upper surface of the first annular sheet. The second annular sheet, the anchor sheet that continuously extends in the radial direction to the first annular sheet and the second annular sheet, and the anchor sheet that is sandwiched between the first annular sheet and the second annular sheet, and the circumferential direction thereof. And an annular electrode extending along. The annular electrode has a pair of electrode wires made of a conductive ink, and the electrode wires are arranged side by side inside and outside in the radial direction of the first annular sheet and the second annular sheet while being insulated from each other. The ends of the electrode wires extend into the anchor sheet while gradually increasing in width .

According to this structure, a hole is formed in the central portion of the moisture sensor by combining the first annular sheet and the second annular sheet. The electrode wires are annularly arranged along the circumference of the hole. One electrode wire is arranged inside the first annular sheet and the second annular sheet in the radial direction, and the other electrode wire is arranged outside the first annular sheet and the second annular sheet in the radial direction. The electrodes are always insulated from each other.

In artificial dialysis treatment, a dialysis needle is punctured into a patient's arm or other required site. The water sensor according to the present invention is attached to a patient's arm or the like such that the puncture site of the dialysis needle is exposed (so that the puncture site is located inside the hole) prior to puncture. Since the adhesive is attached to the lower surface of the first annular sheet, the moisture sensor can be easily adhered and fixed to the patient's arm or the like. Even if blood leaks from the puncture site during dialysis, this blood immediately reaches the first annular sheet and permeates the annular electrode. When the pair of electrode wires arranged between the first annular sheet and the second annular sheet are electrically connected via the blood, the electric resistance value between the two decreases. That is, a current flows between both electrode lines, and this is detected as a signal to detect blood leakage.

This moisture sensor is attached to the patient's arm or the like, but may have any shape as long as it can expose the puncture site of the dialysis needle as described above. That is, the inner diameter of the hole does not have to be set large, and the outer shapes of the first annular sheet and the second annular sheet are designed compact. Thus, it can be easily attached to the patient's arm as well as to the neck and groin, anywhere on the patient's body, and if blood leaks, it is quickly detected. Further, since the adhesive is applied to the first annular sheet, the moisture sensor can be easily and reliably fixed to any part of the patient's body without using another member such as a tape.

(2) It is preferable that an electric resistance element is connected between the pair of electrode wires.

In this configuration, the presence or absence of disconnection of each electrode wire is detected by constantly applying a predetermined voltage between the pair of electrode wires. That is, when no break occurs in each electrode wire, a constant current corresponding to the applied voltage and the resistance value of the electric resistance element flows in each electrode wire, but when a break occurs in the electrode wire, The electrodes are insulated from each other, and no current flows. When blood leaks, the resistance value between the electrode wires is extremely lowered by the blood, and a large current flows through each electrode wire.

(3) One end of each electrode wire is close to the other end of each electrode wire, and the first annular sheet and the second annular sheet are between the one end and the other end of each electrode wire. Is preferably detachably cut.

In this configuration, since the first annular sheet and the second annular sheet are partially cut in the radial direction, one end and the other end of each electrode wire are separated from each other. Therefore, at the site of artificial dialysis treatment, one end and the other end of each electrode wire are separated after the dialysis needle has been punctured in the patient in advance, and the dialysis needle is placed in the hole of the moisture sensor. .. This makes it easier for doctors and nurses to puncture the dialysis needle and perform other procedures.

Further, one end of each electrode wire is close to the other end portion of each electrode wire, and the first annular sheet and the second annular sheet are provided between one end and the other end portion of each electrode wire. Perforations may be formed.

In this configuration, since the first annular sheet and the second annular sheet are partially pulled in the radial direction with the perforation as a boundary, the both are cut at the perforation, so that one end of each electrode wire is cut. Is separated from the other end. Therefore, at the site of artificial dialysis treatment, one end and the other end of each electrode wire are separated after the dialysis needle has been punctured in the patient in advance, and the dialysis needle is placed in the hole of the moisture sensor. .. This makes it easier for doctors and nurses to puncture the dialysis needle and perform other procedures.

When the first annular sheet and the second annular sheet are cut between one end and the other end of each electrode wire, or when the perforations are provided, the site of artificial dialysis treatment In the above, not only does the work of cutting the moisture sensor with scissors or the like become unnecessary, but also the risk of adhering bacteria etc. to the cut surface is avoided when cutting with the scissors or the like.

(4) It is preferable that an adhesive is provided on the lower surface of the first annular sheet.

With this configuration, the lower surface of the first annular sheet is attached to the skin of the patient via the adhesive. Therefore, since the lower surface of the first annular sheet faces the patient's skin with the adhesive in between and the annular electrode is arranged on the upper surface of the first annular sheet, sweat is generated from the patient's skin during treatment. Even if it does, the sweat does not cause conduction between the annular electrodes. That is, malfunction due to sweat is avoided.

(5) The adhesive may be provided on the lower surface of the first annular sheet via a waterproof sheet.

In this configuration, since the waterproof sheet is interposed between the patient's skin and the annular electrode, even if sweat is generated from the patient's skin during treatment, the sweat causes conduction between the annular electrodes. Is reliably prevented.

(6) It is preferable that an anchor sheet extending in the radial direction is provided continuously to the first annular sheet and the second annular sheet, and the other end of each electrode wire extends into the anchor sheet.

In this configuration, since the other end of each electrode wire extends to the anchor sheet, a connector or the like can be easily connected to this anchor sheet. As a result, when the above-mentioned blood leakage or electrode wire breakage occurs, a signal as a change in current is easily detected via the connector or the like.

According to the present invention, since the moisture sensor is designed compactly, it can be quickly and accurately attached to any part of the body. Moreover, leakage of blood during artificial dialysis is immediately detected.

FIG. 1 is a diagram schematically showing a moisture detecting device in which a moisture sensor according to an embodiment of the present invention is adopted. FIG. 2 is a perspective view schematically showing the cross-sectional structure of the moisture sensor according to the embodiment of the present invention. FIG. 3 is an electrical system diagram of a moisture detecting device using the moisture sensor according to the embodiment of the present invention. FIG. 4 shows a usage state when the water detection device according to one embodiment of the present invention is used for artificial dialysis treatment. FIG. 5 is a conceptual diagram of a conventional moisture detecting device used for artificial dialysis treatment. FIG. 6 is a perspective view showing a usage state of a conventional moisture detecting device. FIG. 7: is a perspective view which shows the use condition of the conventional improved moisture detection apparatus.

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the drawings as appropriate.

FIG. 1 is a diagram schematically showing a moisture detecting device in which a moisture sensor according to an embodiment of the present invention is adopted.

The water detecting device 10 mainly monitors bleeding from a patient during artificial dialysis treatment. The moisture detector 10 includes a moisture sensor 11. If water sensor 11 is attached to the arm of a patient during treatment and blood leaks, water sensor 11 detects this. The moisture sensor 11 is connected to the alarm 13 via the connector 14. The alarm 13 includes a buzzer 12, and the buzzer 12 sounds when the water sensor 11 detects a blood leak.

In the present embodiment, the moisture detecting device 10 is used to monitor blood leakage during artificial dialysis, but the moisture detecting device 10 may be used for other purposes, such as a device for monitoring liquid leakage during infusion. , It can be used as a device for monitoring blood leakage from a wound after surgery. Further, in the present embodiment, the moisture sensor 11 is attached to the arm of the patient, but the moisture sensor 11 may be attached to a part other than the arm. For example, when this moisture detecting device 10 is used for artificial dialysis treatment, the location where the moisture sensor 11 is attached is, for example, the neck or groin in addition to the arm.

1. Moisture sensor structure

The moisture sensor 11 is formed in a ring shape as shown in FIG. 1, and is thin and flexible as a whole. That is, the moisture sensor 11 includes a flexible main sheet 31 and the like (see FIG. 2) which will be described later, and has an annular portion 27 and a leg portion 28 (an “anchor sheet” described in the claims). Equivalent). Both are integrally formed. A pair of annular electrodes 25 and 26 are arranged side by side on the annular portion 27, and further, an electric resistance element 29 is arranged so as to bridge the electrodes. The electric resistance element 29 is arranged at the ends of the annular electrodes 25 and 26. Each annular electrode 25, 26 extends on the leg 28 side. By attaching the connector 14 to the leg portion 28, the annular electrodes 25 and 26 are electrically connected to the connector 14. Further, the annular portion 27 is cut in the radial direction, and the slit 18 is formed.

In the present embodiment, the outer diameter of the annular portion 27 is set to 38 mm and the inner diameter is set to 18 mm. The size of the annular portion 27 is not particularly limited as long as the inner diameter is about 10 mm or more. Therefore, the outer shape of the annular portion 27 is not limited to the circular shape and may be any other shape as long as it is a ring shape. However, it is desirable that the annular portion 27 be designed compact. The leg portion 28 has a rectangular shape with a width dimension of 18 mm and a longitudinal dimension of 25 mm. The size of the leg portion 28 is not particularly limited as long as it is large enough for the connector 14 to be connected. The electric resistance element 29 does not necessarily have to be arranged at the ends of the annular electrodes 25 and 26, and may be omitted.

FIG. 2 is a perspective view schematically showing the cross-sectional structure of the moisture sensor 11. In FIG. 2, the arrow 15 indicates the lower side of the moisture sensor 11, and the lower surface of the moisture sensor 11 in the figure contacts the arm of the patient. The arrow 16 indicates the inside of the moisture sensor 11, and the arrow 17 indicates the circumferential direction of the annular portion 27.

As shown in FIG. 2, the moisture sensor 11 has a multilayer structure. That is, the moisture sensor 11 includes a main sheet 31 (corresponding to the “first annular sheet” described in the claims) including the annular electrodes 25 and 26 and the electric resistance element 29 (see FIG. 1), and the main sheet. 31 and a sub-sheet 32 (corresponding to the “second annular sheet” recited in the claims) disposed above the electro-conductive adhesive 34 between the main sheet 31 and the sub-sheet 32. Intervened. The main sheet 31 includes a waterproof sheet 33 and a release sheet 40. An adhesive agent 35 is interposed between the main sheet 31 and the waterproof sheet 33, and an adhesive agent is also applied between the waterproof sheet 33 and the release sheet 40. 41 is interposed.

The main seat 31 and the sub-seat 32 are formed in a shape as shown in FIG. 1, and each of them constitutes the annular portion 27 and the leg portion 28. In the present embodiment, the main sheet 31 is made of Japanese paper. However, the material forming the main sheet 31 need not be limited to Japanese paper. In short, paper or cloth may be used as long as it is flexible and water-absorbent, hardly soluble in water, and electrically insulating in a dry state. The thickness of the main sheet 31 is set to about 0.3 mm to 0.8 mm. Slits are formed in the main sheet 31. That is, the portion of the main seat 31 that constitutes the annular portion 27 is cut in the radial direction. The slit formed in the main sheet 31 constitutes the slit 18 formed in the annular portion 27.

The annular electrodes 25, 26 are composed of electrode wires made of silver paste ink. The annular electrodes 25 and 26 are not limited to the silver paste ink as long as they are conductive inks, and may be conductive water-soluble carbon inks, for example. The annular electrodes 25 and 26 are printed on the upper surface 38 (see FIG. 2) of the main sheet 31, and extend along the circumferential direction of the main sheet 31, as shown in FIG.

The annular electrode 25 is arranged radially outside the main seat 31, and the annular electrode 26 is arranged radially inside the main seat 31. Both are arranged so as not to contact each other, and as shown in FIG. 2, the distance s between the annular electrodes 25 and 26 is set to about 5 mm. The width w of the annular electrodes 25, 26 is set to about 2 mm. As shown in FIG. 1, in the present embodiment, since the electric resistance element 29 is arranged, the annular electrodes 25 and 26 are electrically connected, but the electric resistance element 29 is omitted as described above. If so, the annular electrodes 25, 26 are insulated from each other.

One end 19 of the annular electrode 25 circulates on the main seat 31 from one side in the vicinity of the slit 18 and extends toward the leg portion 28 side. The other end 20 of the annular electrode 25 is formed so as to have a large width, and is electrically connected to the connector 14 reliably. One end 21 of the annular electrode 26 circulates on the main seat 31 from one side near the slit 18, passes through the leg portion 28, and extends to the other side near the slit 18. Further, the annular electrode 26 is inverted on the other side near the slit 18, extends on the main seat 31 along the circumferential direction, and then extends to the leg portion 28 side. The other end 22 of the annular electrode 26 is formed to have a larger width like the other end 20 of the annular electrode 25, and is electrically connected to the connector 14 reliably.

In this embodiment, the annular electrodes 25 and 26 are formed by various printing methods using silver paste ink. That is, gravure printing, offset printing, silk printing, letterpress printing is adopted according to the characteristics (thickness, conductivity, etc.) required for the annular electrodes 25, 26. For example, by adopting silk printing, the thickness of the annular electrodes 25 and 26 is set extremely small, and as a result, the flexibility of the main sheet 31 is not impaired.

The sub seat 32 is formed in the same shape as the main seat 31 and has slits formed therein. That is, the portion of the sub-sheet 32 that constitutes the annular portion 27 is cut in the radial direction. The slit formed on the sub-sheet 32 constitutes the slit 18 formed on the annular portion 27. The sub-seat 32 completely covers the upper surface 38 of the main seat 31. The sub-sheet 32 is also made of Japanese paper in this embodiment, and its thickness is set to about 0.3 mm to 0.8 mm. The material of which the sub-sheet 32 is made is not limited to Japanese paper. In short, any material can be used as long as it is highly water-absorbent, hardly soluble in water, and electrically insulating in a dry state. The sub-sheet 32 may be omitted.

In this embodiment, the conductive adhesive 34 is a water-soluble adhesive in which sodium chloride (salt) is kneaded. However, instead of sodium chloride, magnesium chloride, potassium chloride, calcium carbonate or the like may be adopted. Note that the saline solution may be absorbed in the sub-sheet 32 in advance and dried before the sub-sheet 32 is bonded to the main sheet 31. As a result, the annular electrodes 25 and 26 are sandwiched between the main sheet 31 and the sub-sheet 32, and the conductive adhesive 34 and the sub-sheet 32 are electrically insulated in a dry state, and the conductive adhesive 34 or the sub-sheet 32 is provided. Is electrically connected with water being absorbed.

As the conductive adhesive 34, specifically, a paste composed of, for example, potato starch 1% by mass or more and 5% by mass or less, salt 5% by mass or more and 21% by mass or less, and water 74% by mass or more and 94% by mass or less is adopted. obtain. The amount of this salt may be an amount in the vicinity of its saturated solubility that allows it to be dissolved in water at room temperature. This glue is produced by mixing water, salt and potato starch, and stirring with heating. Then, if the agitated product has a uniform consistency, the agitated product is cooled to produce a conductive paste. The conductive adhesive 34 may be omitted.

The waterproof sheet 33 is formed in the same shape as the main sheet 31, and has slits. That is, the portion of the waterproof sheet 33 that constitutes the annular portion 27 is cut in the radial direction. The slit formed on the waterproof sheet 33 constitutes the slit 18 formed on the annular portion 27. The waterproof sheet 33 completely covers the lower surface of the main sheet 31. The waterproof sheet 33 is made of, for example, a polyethylene terephthalate film. Since this polyethylene terephthalate film is highly flexible, the flexibility of the moisture sensor 11 is not impaired. The material forming the waterproof sheet 33 is not particularly limited, and polypropylene, ethylene vinyl acetate copolymer film, polytetrafluoroethylene film, etc. may be adopted. The waterproof sheet 33 may be omitted.

As the adhesive 35 for adhering the waterproof sheet 33 to the main sheet 31, that is, the adhesive 35 applied to the upper surface of the waterproof sheet 33, urethane glue or other general-purpose industrial glue can be adopted. Needless to say, when the waterproof sheet 33 is omitted, the adhesive 35 is also omitted.

As the adhesive 41 attached to the lower surface of the waterproof sheet 33, an acrylic adhesive, a rubber adhesive, a silicone adhesive, or any other adhesive used for a bandage may be used. When the waterproof sheet 33 is omitted, the adhesive 41 is attached to the lower surface of the main sheet 31.

The release sheet 40 is formed in the same shape as the main sheet 31 and has slits. That is, the part of the release sheet 40 that constitutes the annular portion 27 is cut in the radial direction. The slit formed in the release sheet 40 constitutes the slit 18 formed in the annular portion 27. The release sheet 40 completely covers the lower surface of the waterproof sheet 33. The release sheet 40 is composed of paper such as glassine paper as a base material and a release layer in contact with the adhesive 41. The peeling layer is made of, for example, silicon resin. When the moisture sensor 11 is in the unused state, the release sheet 40 is in a state of being bonded to the waterproof sheet 33 via the adhesive 41. When the moisture sensor 11 is used, the release sheet 40 is released from the waterproof sheet 33. Then, the moisture sensor 11 is attached to the arm or other part of the patient with the adhesive 41.

As described above, the electric resistance element 29 is arranged on the upper surface 38 of the main sheet 31 and is bridged between the annular electrodes 25 and 26, so that the annular electrodes 25 and 26 are electrically connected. By arranging the electric resistance element 29, current is supplied between the annular electrodes 25 and 26 even when the sub-sheet 32 and the conductive adhesive 34 do not contain water. Thereby, it is possible to easily confirm that the moisture sensor 11 is in an operable state (no disconnection or the like has occurred in the annular electrodes 25, 26) without requiring application of a high voltage.

What is the resistance value of the electric resistance element 29? Usually, it is set to about 20 kΩ to 5 kΩ. Therefore, when the sub-sheet 32 and the conductive adhesive 34 are in a dry state, the electric resistance value between the annular electrodes 25 and 26 is the same as the resistance value of the electric resistance element 29. When water is present in the sub-sheet 32 and the conductive adhesive 34, the annular electrodes 25 and 26 are energized via the water, so that the electrical resistance value between the two rapidly decreases. Therefore, the moisture sensor 11 can reliably detect the presence of moisture, that is, the presence or absence of bleeding.

This electric resistance element 29 can also be formed by printing using conductive ink. Carbon ink is preferably used as the conductive ink forming the electric resistance element 29. The carbon used in this carbon ink is preferably a non-graphitizable material such as phenol resin, furfuryl alcohol, vinylidene chloride, cellulose and wood. This conductive ink is prepared by kneading carbon powder and a binder made of a resin such as phenol or epoxy to form a paste. The conductive ink forming the electric resistance element 29 is printed on the upper surface 38 of the main sheet 31.

FIG. 3 is an electric system diagram of the moisture detector 10 using the moisture sensor 11.

The moisture detector 10 includes divided resistance circuits C1, C2, C3, comparators H1, H2, buzzers BZ1, BZ2, light emitting diodes LR1, LR2, LB, and resistors r4, r5. .. The resistor circuits C1, C2, C3, the comparators H1, H2, the buzzers BZ1, BZ2, the light emitting diodes LR1, LR2, LB and the resistors r4, r5 are mounted on the alarm device 13. In the moisture detector 10, the output values of the resistance circuits C1 to C3 are compared with each other, and based on the result, five kinds of signals are selectively emitted as will be described later.

The resistance R0 (electrical resistance element 29: see FIG. 1) of the moisture sensor 11 is set to 20 kΩ. The resistance circuit C1 includes a power supply and a resistance r1 (20 kΩ), the resistance circuit C2 includes a resistance r2 (100 kΩ) and a variable resistance R1 (10 kΩ to 20 kΩ), and the resistance circuit C3 includes a resistance r3 (20 kΩ) and a variable resistance. R2 (50 kΩ to 100 kΩ). When the circuit of the moisture detection device 10 is normal, the voltage V0 of the power supply is dispersed into the voltage applied to the resistor R0 and the voltage applied to the resistor r1, and the negative signal input terminal of the comparator H1 and the comparison signal are compared. Is input to the positive signal input terminal of the container H2. When the moisture sensor 11 is not connected or has a poor contact, a value corresponding to the voltage drop due to the resistance r1 of the voltage V0 of the power supply is input to the comparators H1 and H2. In the resistance circuit C2, for example, when the variable resistance R1 is 20 kΩ, a voltage of V0×R1/(r2+R1)=V0/6 is applied to the negative signal input terminal of the comparator H2. In the resistance circuit C3, when the variable resistance R2 is 100 kΩ, the voltage V0×R2/(r3+R2)=V0×5/6 is applied to the positive signal input terminal of the comparator H1.

The power source is connected to the output terminal of the comparator H1 via a resistor r4 (470 kΩ), a red light emitting diode LR1 and a buzzer BZ1. The power source is connected to the output terminal of the comparator H2 via a resistor r4 (470 kΩ), a red light emitting diode LR2, and a buzzer BZ2. The voltage V0 of the power supply is grounded via a resistor r4 and a resistor r5 (470 kΩ). The output terminals of the comparator H1 and the comparator H2 are connected to the signal input terminals of the two-input AND gate AG. The output terminal of the two-input AND gate AG is connected to the blue light emitting diode LB.

When the moisture sensor 11 is not connected, the output of the comparator H1 becomes low level. The low level output of the comparator H1 causes the red diode LR1 to emit light and the buzzer BZ1 to sound. When the moisture sensor 11 is connected, the two outputs of the comparator H1 and the comparator H2 become high level. The output of the two-input AND gate AG, to which these two signals are input, switches to a high level, causing the blue light emitting diode LB to emit light. When the moisture sensor 11 contains blood and the resistance between the electrodes 19 drops to several tens of Ω, the output of the comparator H2 becomes low level, and the red light emitting diode LR2 and the buzzer BZ2 are activated.

2. How to use the moisture detector

FIG. 4 shows a usage state when the moisture detection device 10 is used for artificial dialysis treatment.

The moisture detector 10 is used in the following manner. As shown in the figure, the moisture sensor 11 is used to monitor blood leakage in artificial dialysis treatment.

A dialysis needle is punctured into the patient's arm. Although the part to be punctured in the figure is the arm, it may be punctured not only in the arm but also in a required part. The moisture sensor 11 is attached to the patient's arm so as to surround the puncture site. Specifically, the annular portion 27 is twisted and expanded at the slit 18, and the moisture sensor 11 is positioned so that the dialysis needle is relatively arranged inside the annular portion 27. That is, the water sensor 11 is arranged between the patient's skin and the dialysis needle so as to avoid the dialysis needle and surround the dialysis needle. Then, the release sheet 40 (see FIG. 2) is released, and the moisture sensor 11 is attached so as to surround the vicinity of the puncture site. When blood leaks from the place where the dialysis needle is punctured in this state, the blood comes into contact with the moisture sensor 11 and wets the sub-sheet 32 and the conductive adhesive 34. That is, blood permeates from the upper surface 38 side of the main sheet 31, the annular electrodes 25 and 26 are electrically connected via blood, and the buzzers BZ2a and BZ2b operate as described above.

The water sensor 11 according to the present embodiment is sufficient if it can surround the puncture site of the dialysis needle, and therefore can be designed compactly. Therefore, the moisture sensor 11 can be quickly and accurately attached to any part of the body other than the arm, and moreover, leakage of blood during artificial dialysis can be immediately detected.

In the present embodiment, since the electric resistance element 29 is connected between the annular electrodes 25 and 26, a predetermined voltage is constantly applied between the annular electrodes 25 and 26, so that the annular electrodes 25 and 26 are not broken. Is detected. That is, when no disconnection occurs in each annular electrode 25, 26, a constant current corresponding to the voltage applied to each annular electrode 25, 26 and the resistance value of the electric resistance element 29 flows, but the disconnection occurs. If this happens, this current will stop flowing. Therefore, the presence or absence of disconnection of each annular electrode 25, 26 is detected. When a blood leak occurs, the resistance value between the annular electrodes 25 and 26 is extremely lowered by the blood, and thus the blood leak is detected in the above-described manner. However, the electric resistance element 29 may be omitted.

Further, since the slit 18 is provided in the annular portion 27, the moisture sensor 11 is arranged around the puncture site after the dialysis needle is punctured in the patient in advance at the site of artificial dialysis treatment. This makes it easier for doctors and nurses to puncture the dialysis needle and perform other procedures. The slit 18 may be omitted. In that case, prior to the puncture of the dialysis needle, the moisture sensor 11 is attached to the patient's arm or the like so that the puncture site of the dialysis needle is exposed.

In the present embodiment, as shown in FIG. 2, since the adhesive 41 is provided on the lower surface of the main sheet 31, the lower surface of the moisture sensor 11 is attached to the skin of the patient via the adhesive 41. .. That is, the lower surface of the main sheet 31 faces the skin of the patient with the adhesive 41 interposed therebetween. Moreover, since the annular electrodes 25 and 26 for detecting blood leakage are arranged on the upper surface 38 of the main sheet 31, even if sweat is generated from the skin of the patient during the treatment, the sweat causes a gap between the annular electrodes 25 and 26. Is not conducted, and malfunction due to sweat is avoided.

Moreover, in this embodiment, since the main sheet 31 includes the waterproof sheet 33, the adhesive 41 is arranged on the lower surface of the main sheet 31 via the waterproof sheet 33. In other words, since the waterproof sheet 33 is interposed between the adhesive 41 and the annular electrodes 25 and 26, even if sweat is generated from the skin of the patient during treatment, the annular electrode 25, It is possible to reliably prevent electrical connection between the 26 and 26.

Furthermore, the moisture sensor 11 includes a leg portion 28, and the annular electrodes 25 and 26 are extended to the leg portion 28. Therefore, the connector 14 is easily connected to the leg portion 28, and the setting of the moisture detecting device 10 is facilitated. Further, when blood leaks during dialysis or disconnection of the annular electrodes 25 and 26 occurs, a signal as a change in current value can be detected simply and quickly via the connector 14. The leg portion 28 may be omitted. In that case, the connector 14 is directly connected to the annular electrodes 25 and 26 of the annular portion 27.

3. Modification

In the present embodiment, as shown in FIG. 1, the moisture sensor 11 is provided with the slit 18, but perforations may be formed instead of the slit 18. By forming the perforations, a nurse or the like cuts the perforations when the moisture sensor 11 is attached to the patient. This work is easily performed by pulling the moisture sensor 11 in the radial direction with the perforation as a boundary. By forming the slits 18 and the perforations, the work of cutting the water sensor 11 with scissors or the like becomes unnecessary at the site of artificial dialysis treatment. In addition, when cutting with scissors or the like, there is a risk that bacteria and the like will adhere to the cut surface, but this risk is also avoided.

10... Moisture detector 11... Moisture sensor 18... Slit 19... One end 20... The other end 21... The other end 25... Annular electrode 26... Annular electrode 29... -Electrical resistance element 31... Main sheet 32... Sub-sheet 33... Waterproof sheet 34... Conductive adhesive 35... Adhesive 38... Top surface 40... Release sheet 41... ·adhesive

Claims (6)

A first annular sheet having water absorption and having an adhesive on its lower surface;
A second annular sheet adhered to the upper surface of the first annular sheet via a conductive adhesive that exhibits insulating properties when dried and exhibits conductivity when absorbing water;
An anchor sheet continuously extending in the radial direction to the first annular sheet and the second annular sheet,
An annular electrode sandwiched between the first annular sheet and the second annular sheet, and extending along the circumferential direction thereof,
The annular electrode has a pair of electrode wires made of conductive ink,
The respective electrode wires are arranged side by side inside and outside in the radial direction of the first annular sheet and the second annular sheet, while being insulated from each other ,
A moisture sensor in which an end portion of each of the electrode wires extends into the anchor sheet while gradually increasing in width . The moisture sensor according to claim 1, wherein an electric resistance element is connected between the pair of electrode wires. One end of each electrode wire is close to the other end of each electrode wire, and the first annular sheet and the second annular sheet can be separated from one end of the electrode wire and the other end thereof. The moisture sensor according to claim 1, which is cut into pieces. One end of each electrode wire is close to the other end of each electrode wire, and the first annular sheet and the second annular sheet are perforated between one end and the other end of each electrode wire. The moisture sensor according to claim 1, wherein the moisture sensor is formed. The moisture sensor according to claim 1, wherein an adhesive is provided on the lower surface of the first annular sheet. The moisture sensor according to claim 5, wherein the adhesive is provided on the lower surface of the first annular sheet via a waterproof sheet.

Images