WO2024048736A1

WO2024048736A1 - Liquid detection device for medical use

Info

Publication number: WO2024048736A1
Application number: PCT/JP2023/031863
Authority: WO
Inventors: 衝貞廣; 健志山口; 康平山辺
Original assignee: ニプロ株式会社
Priority date: 2022-09-01
Filing date: 2023-08-31
Publication date: 2024-03-07

Abstract

Provided is a liquid detection device that is for medical use, that has a novel structure, and in which the detection accuracy is unlikely to be affected even if liquid leakage takes place at a slightly displaced location. A liquid detection device (10) for medical use comprises: a transmission unit (16) which transmits millimeter waves as a transmission signal; a reception unit (18) which receives reflection waves of the transmission signal as a reception signal; and a detection unit (20) which electrically detects a medical detection target liquid (5) on the basis of the reception signal.

Description

Medical liquid detection device

The present invention relates to a medical liquid detection device used to detect blood leakage in the medical field.

In the medical field, fluid leakage can sometimes be a problem in treatments that require long-term treatment, and for this reason, it is necessary to detect fluid leaks as early as possible when they occur. In some cases, For example, during dialysis, liquid leakage (liquid leakage), where blood or drug solution leaks from the puncture site, may occur due to the needle being pulled out of the patient, etc., and it is necessary to detect and deal with liquid leakage before it becomes a major problem. There is. However, since it is not realistic for busy medical personnel to continuously monitor dialysis treatment from start to completion, the adoption of liquid detection devices that automatically detect liquid leakage is being considered.

Conventionally, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 2012-196293 (Patent Document 1), a patient's forearm is placed on a sheet having a plurality of detection wirings, and when leaked liquid such as blood comes into contact with the detection wirings, electricity is generated. An electrical resistance type liquid detection device has been proposed, in which liquid leakage is detected based on a change in electrical resistance when the electrical resistance is short-circuited. Furthermore, as in Japanese Patent No. 6534316 (Patent Document 2), a camera-type liquid detection device that optically monitors a detection target using a camera has also been proposed.

Japanese Patent Application Publication No. 2012-196293 Patent No. 6534316

However, electrical resistance type liquid detection devices such as those disclosed in Patent Document 1 can detect even a small amount of liquid depending on its position and how it spreads, so it may falsely detect liquids that do not need to be detected, such as patient sweating. There was a risk that In addition, in a camera-type liquid detection device such as Patent Document 2, for example, when a puncture site where liquid leakage is expected to occur during sleep is covered with a futon, the liquid to be detected is absorbed by the futon and is not detected. There are also possible situations.

An object of the present invention is to provide a medical liquid detection device with a novel structure that enables more stable detection of liquid leakage.

Hereinafter, preferred embodiments for understanding the present invention will be described. However, each of the embodiments described below is described by way of example, and may not only be adopted in combination with each other as appropriate, but also be described in each embodiment. The plurality of components can be recognized and employed as independently as possible, and can also be appropriately employed in combination with any of the components described in other embodiments. Accordingly, the present invention is not limited to the embodiments described below, and various other embodiments can be realized.

The first aspect is a medical liquid detection device, which includes a transmitter that transmits a millimeter wave as a transmission signal, a receiver that receives a reflected wave of the transmission signal as a reception signal, and a medical liquid detection device that detects a medical liquid. The detection unit includes a detection unit that electrically detects based on the received signal.

According to the medical liquid detection device having the structure according to this aspect, leakage of medical detection target liquids (hereinafter sometimes referred to as detection target liquids) such as blood and drug solutions can be detected by changes in the millimeter wave reception state. For example, if a liquid leak is detected when the amount of liquid increases and there is a sufficiently large change in the reception status of millimeter waves, it will be possible to detect a relatively small amount of liquid, such as sweating, by mistake. becomes difficult to detect. Furthermore, even if the leakage site of the liquid to be detected is covered with clothing, bedding, etc., for example, the reception state of millimeter waves changes depending on the presence or absence of the liquid to be detected, so that accurate detection is possible. Further, since the liquid to be detected is detected based on a change in the reception state of the reflected millimeter wave, the device for detecting a change in the reception state can be separated from the detection target site. Therefore, even if the position of leakage is slightly shifted, the detection accuracy is hardly affected, and highly accurate detection can be stably performed.

In a second aspect, the medical liquid detection device according to the first aspect includes a base member that restricts passage of the medical detection target liquid, and the transmitter is disposed above the base member. and the transmission signal is transmitted from above toward the base member.

According to the medical liquid detection device having the structure according to the present aspect, the intensity of the millimeter wave reflected wave received by the receiving section changes as the amount of the liquid to be detected on the base member increases. , the liquid to be detected can be detected more reliably. Further, since the millimeter wave transmitter can be placed above, it is difficult for a medical worker to unintentionally come into contact with the liquid detection device and cause a malfunction of the transmitter.

In a third aspect, in the medical liquid detection device described in the first or second aspect, the detectable range of the medical detection target liquid is set with reference to the position of the patient's body.

According to the medical liquid detection device structured according to this aspect, for example, when a liquid to be detected such as blood or a drug solution leaks from a puncture site in a patient's arm during artificial dialysis or infusion, the liquid to be detected is Since the liquid accumulates under the patient's arm, by setting the detectable range of the liquid to be detected based on the position of the patient's arm, the liquid to be detected can be detected with high accuracy. Further, even if the patient's arm moves, for example, it is possible to reduce the situation where the patient's arm is out of the detectable range, and it is possible to stably detect the liquid to be detected.

A fourth aspect is the medical liquid detection device according to any one of the first to third aspects, further comprising a notification device that notifies detection of the medical detection target liquid by the detection unit. It is.

According to the medical liquid detection device having the structure according to this aspect, the notification device notifies medical personnel, patients, people around the patient, etc. of the detection of the liquid to be detected, so that liquid leakage can be promptly detected. can be dealt with. Note that the notification method of liquid leakage detection by the notification device is not particularly limited, and for example, sounding a warning sound, lighting a warning light, notifying a mobile device, etc. may be employed.

According to the present invention, more stable detection of liquid leakage is possible in a medical liquid detection device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a case where the medical liquid detection device according to the first embodiment of the present invention is used to detect liquid leakage from a puncture site in a forearm of a blood circuit, and shows a state before liquid leakage occurs. Functional block diagram of the medical liquid detection device shown in Figure 1 FIG. 2 is a diagram showing a case where the medical liquid detection device shown in FIG. 1 is used to detect leakage from a puncture site in a forearm of a blood circuit, and shows a state after fluid leakage has occurred. Flowchart showing the liquid leakage detection process of the medical liquid detection device shown in Figure 1 2 is a graph showing detection results by the medical liquid detection device of FIG. 1 before liquid leakage occurs. 2 is a graph showing detection results by the medical liquid detection device of FIG. 1, where the leakage amount is 100 ml. 2 is a graph showing the detection results by the medical liquid detection device of FIG. 1, where the leakage amount is 300 ml. A diagram showing a medical liquid detection device as another embodiment of the present invention, in which the detection device main body is attached to the ceiling of a room.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a medical liquid detection device 10 as a first embodiment of the present invention. The liquid detection device 10 monitors the leakage of blood 5 as a medical detection target liquid due to needle dislodgement, etc. at the puncture site of the patient's forearm 4 of the blood collection port 2 and blood return port 3 of the artificial dialysis device 1. . In the following description, the vertical direction basically refers to the vertical vertical direction when the liquid detection device 10 is in use.

As shown in FIG. 2, the liquid detection device 10 includes a detection device main body 12 and a notification device 14. The detection device main body 12 includes a transmitting antenna 16 as a transmitting section that transmits millimeter waves as a transmitting signal, and a receiving antenna 18 as a receiving section that receives reflected waves of the millimeter waves transmitted from the transmitting antenna 16 as a received signal. , is equipped. Each of the transmitting antenna 16 and the receiving antenna 18 may be one or more. For example, if the area where there is a risk of blood leakage is likely to be hidden by the patient's body, such as the torso or arms, transmit signals that can see both sides of the body so that both sides of the body can be monitored using millimeter waves. The antenna 16 and the receiving antenna 18 can be installed, and in that case, it is also possible to use a millimeter wave reflector or the like. Further, by providing a transmitting/receiving switch that switches between transmitting and receiving antennas, the transmitting section and the receiving section can be configured with one common antenna. Note that, since a medical field is a place where various people come and go, the detection device main body 12 is preferably located above the patient, and the transmitting and receiving section is preferably incorporated into a single device.

The detection device main body 12 includes a signal processing section 20 as a detection section. The signal processing unit 20 is configured with a microprocessor such as a central processing unit (CPU), and generates a millimeter wave signal (transmission signal) transmitted from the transmission antenna 16 and also generates a millimeter wave signal (transmission signal) transmitted from the transmission antenna 18. A signal (background signal, detection signal) is generated according to the reflected millimeter wave received by the sensor. Note that the signal processing unit 20 may include an amplifier that amplifies a signal, a DA converter that converts a digital signal to an analog signal, an AD converter that converts an analog signal to a digital signal, and the like.

The detection device main body 12 includes a control section 22. For example, the control unit 22 controls power supply from the power supply 24 to the signal processing unit 20 according to the operating state of the switch 26. Further, the control unit 22 controls the signal processing unit 20 according to input from an external device (not shown) connected via the external connection unit 28, and also controls output to the external device. Note that the external connection section 28 may be, for example, a connector that is physically connected to an external device, or may be configured of a communication chip or the like that is wirelessly connected to the external device. Further, the control unit 22 controls the notification device 14 based on the received signal generated by the signal processing unit 20.

The notification device 14 includes, for example, a light 30 and a speaker 32, and controls whether the light 30 emits light and the speaker 32 emits sound, the manner of the light emission and sound generation (for example, the light emission and sound pattern, the color of the light emitted, the pitch), etc. is controlled by the control section 22. Furthermore, it is also possible to notify doctors, family members, etc. by emitting light or emitting sound from a light 30 or a speaker 32 located at a distance from the detection device main body 12 via wireless communication such as Bluetooth (registered trademark). For example, as the notification device 14, in addition to existing notification devices such as a light 30, a speaker 32, and a smartphone installed in a nurse's waiting room, a light 30 and a speaker 32 may be installed near the entrance of the hospital room to notify the outside of an abnormality. You may also notify the

In the liquid detection device 10 of this embodiment illustrated in FIG. 1, the detection device main body 12 and the notification device 14 are separated from each other, and the detection device main body 12 and the notification device 14 are connected to each other by wire or wirelessly. As shown in FIG. 1, the detection device main body 12 is set on a pole 6 extending upward from the artificial dialysis device 1, and is capable of transmitting millimeter waves to a patient from above. The pole 6 of this embodiment extends upward from the artificial dialysis apparatus 1 and has a tip extending horizontally, making it easy to position the detection device main body 12 above the forearm 4. The notification device 14 is set at a lower position in the artificial dialysis apparatus 1 so that the light emission is easily visible and the operation to stop the light emission and sound generation is easy. Note that the pole 6 may be fixed to a bedside pillar or the like separately from the artificial dialysis apparatus 1, or may be of an independent stand type.

In FIG. 1, a patient is lying on his back on a bed 7, and a blood collection port 2 and a blood return port 3, which are the patient-side ends of the blood circuit of the artificial dialysis device 1, are punctured in the patient's forearm 4. . The needles of the indwelling needles constituting the blood collection port 2 and the blood return port 3 may be made of resin or metal. A sheet 34 is placed below the patient's forearm 4 as a base member to prevent the blood 5 from passing through, making it difficult for the blood 5 to adhere to the bed 7 in the event of leakage, and making it difficult for the blood 5 to adhere to the bed 7. By collecting on the sheet 34, the blood 5 spreads on the sheet 34, making it easier to detect the occurrence of leakage. The structure of the sheet 34 is not particularly limited, but for example, by making the upper layer in contact with the patient's forearm 4 a nonwoven fabric layer, the discomfort caused by the sheet 34 sticking to the forearm 4 is reduced, and the blood 5 is absorbed and retained. In addition, the presence of the resin film layer prevents the blood 5 from passing through and prevents the blood 5 from adhering to the bed 7. Since the sheet 34 has a structure in which a thin non-woven fabric layer is superimposed on the upper surface of the resin film layer, the blood 5 is not locally absorbed in the non-woven fabric layer but is dispersed and absorbed over a wide range. The absorbing region rapidly expands in the surface direction of the sheet 34. Therefore, even if there is a relatively small amount of blood 5, the vertical projected area of the absorption region becomes large, which improves the detection accuracy in leakage detection using millimeter waves transmitted downward toward the patient. be able to. Note that there may be no nonwoven fabric layer on the upper surface of the sheet 34, and the upper surface of the sheet 34 may be made of a resin film or the like, and is a non-absorbent layer that does not absorb liquid leakage or a difficult-to-absorb layer that does not easily absorb liquid leakage. Further, the sheet 34 may be made of a flexible material that can be folded, or may be made of a hard material that cannot be folded. Further, the sheet 34 may be provided with a layer (for example, an aluminum layer) having a higher millimeter wave reflectance than the nonwoven fabric layer or the resin film layer.

The detection device main body 12 transmits millimeter waves from above toward the patient's forearm 4 from the transmitting antenna 16 directly below, and receives reflected waves of the millimeter waves using the receiving antenna 18. Therefore, the detection device main body 12 includes both a millimeter wave transmitting section and a millimeter wave receiving section, and the transmission and reception of millimeter waves is performed by one detection device main body 12 at one location. Note that the positions and directivity of the transmitting antenna 16 and the receiving antenna 18 can be set appropriately according to the position of the patient, the position of the part to be monitored where there is a risk of blood leakage, and are not limited. For example, the transmitting antenna 16 and the receiving antenna 18 may be supported by a flexible arm, a movable link arm, etc., so that the installation position can be easily changed depending on the situation.

When the blood 5 leaks from the puncture site of the blood return port 3 on the patient's forearm 4 as shown in FIG. The signal processing unit 20 electrically detects the blood 5 based on the reflected wave (received signal), and the notification device 14 notifies the detection of liquid leakage. Although FIG. 3 illustrates a case in which blood 5 leaks from the blood return port 3, a case in which blood 5 leaks from the blood sampling port 2 is detected in the same manner.

The liquid detection device 10 monitors the occurrence of liquid leakage, for example, by a process as shown in the flowchart shown in FIG. That is, in step (hereinafter referred to as S) 1, the switch 26 is turned on and power supply from the power supply 24 is started, so that the transmission signal generated by the signal processing unit 20 is transmitted from the transmission antenna 16, and the transmission signal is transmitted from the transmission antenna 16. , the reflected wave of the transmitted signal is received by the receiving antenna 18 as a received signal, and the received signal is transmitted to the signal processing section 20. For example, the switch 26 may be provided on the detection device main body 12, may be provided on the notification device 14 connected to the detection device main body 12 by wire or wirelessly, or may be provided separately from the notification device 14. It may be provided in an operating terminal connected to the detection device main body 12 by wireless communication such as infrared communication.

Next, in S2, the signal processing unit 20 generates a background signal based on the received signal. The background signal is a detection result of a non-liquid detection state obtained by a medical worker while visually monitoring to confirm that there is no liquid leakage, and is stored as a reference signal to be compared with a detection signal described later. Ru. As a specific example, FIG. 5A shows a graph of the distribution of the intensity of the received signal for each distance from the detection device main body 12 based on the background signal. In the graph of FIG. 5A, there is a peak due to the reflected wave from the patient's forearm 4 at a position at a distance of about 50 cm from the receiving antenna 18. Other peaks in the graph of FIG. 5A are unique to the environment due to reflected waves from the bed 7, the floor, etc. in addition to noise, and differ depending on the usage environment.

In addition, the background signal includes not only a height signal that is a detection result in the height direction as shown in FIG. 5A, but also a detection result on a plane (horizontal) that is perpendicular to the height direction and approximately parallel to the floor. A horizontal signal may be obtained in addition to the height signal. Based on the horizontal signal, it is also possible to map the strength distribution of reflected waves of millimeter waves on the horizontal plane. For example, by transmitting and receiving millimeter waves radially, it is possible to transmit and receive millimeter waves in the horizontal axis (X-axis or Y-axis) direction that is perpendicular to the height direction (Z-axis). If blood leakage occurs, the blood 5 gradually spreads on the sheet 34, causing a change in the amount of millimeter wave reflection on the X-axis or Y-axis at the same height as the sheet 34 on the Z-axis.

In S3, the signal processing unit 20 determines whether the background signal acquired in S2 is a normal signal. The background signal determination criterion in S3 is not particularly limited, but is determined based on, for example, whether or not the patient's forearm 4 is detected at a predetermined distance from the receiving antenna 18. That is, in this embodiment, since the detectable range of blood 5 is set based on the forearm 4, which is a part of the patient's body, the forearm 4, which is the reference position of the detectable range of blood 5, is set at an appropriate position. Determine whether or not the position is detected.

Whether or not the position of the forearm 4 is properly detected is determined by, for example, determining in the height direction based on the height signal and determining in the direction perpendicular to the height (horizontal direction) based on the horizontal signal. be done. That is, it is determined whether the horizontal position of the forearm 4 with respect to the detection device main body 12 is appropriate or not based on whether there is a point having a predetermined amount of reflection on the horizontal signal at the height position of the forearm 4. . Note that whether or not the position of the forearm 4 in the horizontal direction based on the horizontal signal is appropriate is determined by, for example, whether the forearm 4 is located within a range of 15 cm on one side with the center of the measurement range as a reference. be done.

The relative position between the detection device main body 12 and the forearm 4 in the height direction is, for example, at least one of the length in the height direction of the pole 6 that supports the detection device main body 12 and the height of the support base that supports the forearm 4. It can be made adjustable by making it variable. Further, the relative position between the detection device main body 12 and the forearm 4 in the horizontal direction can be adjusted by, for example, making the length of the pole 6 variable in the horizontal direction or changing the position of the forearm 4 as appropriate. can.

As a means for arranging the forearm 4 at an appropriate horizontal position with respect to the detection device main body 12, for example, a light projector that projects visible light onto the millimeter wave transmission range or approximately the center of the transmission range can be placed on the detection device main body 12. It is conceivable that the forearm 4 be positioned in accordance with the visible light. In addition, for example, the position of the sheet 34 can be adjusted based on the millimeter wave reception condition by placing a member (radio wave shield) with high millimeter wave reflectance such as aluminum foil on the four corners or sides of the sheet 34. If detection is made easy and the projection range of millimeter waves is set on the sheet 34, the forearm 4 can be appropriately positioned in the horizontal direction by placing the forearm 4 on the sheet 34. Furthermore, based on the horizontal position of the forearm 4 in the background signal acquired in S2, the positions and directions of the transmitting and receiving

antennas

16 and 18 are automatically adjusted so that the forearm 4 is approximately in the center of the detectable range. You may also do so. Furthermore, by setting the transmission direction of the millimeter waves from the detection device main body 12 vertically downward and by positioning the forearm 4 vertically below the detection device main body 12, the relative positions of the detection device main body 12 and the forearm 4 in the horizontal direction can be easily adjusted. It can also be set to . In this case, for example, a sight part for visually identifying the vertically downward direction may be provided on the exterior (case) of the detecting device's main body 12 so that the vertically downwardly direction can be easily identified by the outer shape of the detecting device's main body 12. . Note that the method for setting the relative position between the detection device main body 12 and the forearm 4 as described above, in other words, the method for setting the reference position of the detectable range, is merely an example and is not particularly limited.

For example, when setting the relative position in the height direction between the detection device main body 12 and the forearm 4 in advance, the determination of the position based on the height signal may be omitted and only the determination based on the horizontal signal may be performed. . In this case, for example, by making it possible to change the length of the pole 6 in the height direction and adjusting the length of the pole 6 in advance, the relative height of the detection device body 12 to the forearm 4 can be adjusted. You can set the position appropriately. For example, the length of the pole 6 can be easily adjusted by providing a display section (a scale indicating the height or a mark for aligning the pole to the same height position as the forearm 4) on the pole 6. As a result, the relative position of the detection device main body 12 and the forearm 4 in the height direction can be set more accurately and easily.

For example, when positioning the forearm 4 with respect to the detection device main body 12 using visible light, a scale, etc. as described above, the determination of the background signal in S3 can be omitted. In this case as well, the acquisition of the background signal in S2 may be executed, for example, for comparative analysis with an abnormal signal in S7, which will be described later.

Furthermore, if the reference position of the blood 5 detection range is other than the forearm 4, the determination criterion in S3 may be, for example, whether the target at the reference position is detected at an appropriate position. Specifically, for example, it is possible to set the reference position of the detection range of blood 5 to the bed 7, sheet 34, or futon, and in that case, the bed 7, sheet 34, or futon may be located at appropriate positions in the background signal. The criterion for determining the background signal in S3 is whether or not the background signal is detected. Note that the cloth parts of futons and beds have low density and low reflectance of millimeter waves, so it is difficult to directly identify the position using millimeter waves. It is also possible to indirectly specify the position of the bed or the futon placed on the upper side of the forearm 4 based on the detected position of the forearm 4, and use the position of the bed or the futon as the reference position.

If it is determined in S3 that the background signal is not normal (No), the control unit 22 controls the notification device 14 to notify the error by turning on the light 30 and emitting sound from the speaker 32 in S4. In this case, for example, after moving the patient's forearm 4 to an appropriate position, the liquid sensing device 10 may be restarted to acquire the background signal again. In notifying the above-mentioned error, it is also conceivable to prompt the patient or the medical worker to adjust the position of the detection device main body 12 or the position of the patient's forearm 4 by using audio or light guidance. Furthermore, by irradiating the millimeter wave projection range with visible light to make the millimeter wave projection range visible, it is also possible to easily set the relative position between the detection device main body 12 and the forearm 4 appropriately.

If it is determined in S3 that the background signal is normal (Yes), the detected position of the forearm 4 is set as the reference position of the liquid detectable range, and the detectable range of blood 5 is set near the forearm 4. At the same time, in S5, the transmission of the transmission signal from the transmission antenna 16 and the reception of the reflected wave (reception signal) by the reception antenna 18 are started, and monitoring of liquid leakage is started.

In this embodiment, as described above, the range in which liquid leakage is detected by millimeter waves (the range in which blood 5 can be detected) is limited to the vicinity of the forearm 4. Therefore, the amount of processing required to analyze data obtained by transmitting and receiving millimeter waves is reduced, and calculation processing time and calculation load are reduced. The width of the range in which liquid leakage can be detected includes areas on the forearm 4 where liquid leakage is expected to occur, areas where leakage is expected to accumulate, and other areas where liquid leakage detection is considered necessary. If so, there are no particular limitations.

Furthermore, in this embodiment, the position of the forearm 4 is also monitored in addition to monitoring the presence or absence of liquid leakage. For example, when the arm moves on the sheet 34, the amount of reflection at the height of the forearm 4 changes horizontally. Therefore, it is possible to continue monitoring the moving forearm 4, and it is possible to monitor whether the forearm 4 is out of the detectable range. Note that it is desirable that the completion of setting the reference position be notified by sound, light, or the like. Further, after completion of setting the reference position, monitoring for liquid leakage may be started automatically, or monitoring for liquid leakage may be started manually by, for example, pressing a monitoring start switch. Furthermore, after the monitoring of liquid leakage has started, a display mechanism may be provided to indicate that monitoring is in progress. For example, a "beep" sound may be periodically emitted to notify that leakage monitoring is continuing normally.

Since the position of the forearm 4 is set as the reference position of the liquid detectable range, the transmission signal is transmitted from the transmission antenna 16 toward the forearm 4 and its surroundings. However, since the blood 5 leaking from the punctured part of the forearm 4 is detected on the sheet 34, the signal used to detect the presence or absence of blood 5 is preferably transmitted from both sides of the forearm 4 in the width direction. and is transmitted downward by a length corresponding to the thickness of the forearm 4 with respect to the upper surface of the forearm 4. By doing this, even if the forearm 4 moves on the seat 34 and the amount of millimeter waves reflected at the height of the forearm 4 changes, this can be prevented from being mistakenly detected as blood leakage. can. On the other hand, a signal for detecting the position of the forearm 4 is transmitted upward toward the forearm 4 than a transmission signal for detecting the presence or absence of blood 5 . In short, in this embodiment, the blood 5 and the forearm 4 are set as monitoring targets depending on two purposes: whether or not blood leakage has occurred and whether or not the forearm 4 is within the monitoring target range. millimeter waves are transmitted to those monitored targets. Note that from S5 onwards, the liquid detection device 10 automatically monitors liquid leakage, so the medical worker can leave the patient and the liquid detection device 10.

In S6, the signal processing unit 20 generates a detection signal based on the received signal transmitted from the receiving antenna 18 to the signal processing unit 20. 5A to 5C are graphs showing the distribution of the intensity of the received signal for each distance from the receiving antenna 18 based on the detected signal. Note that FIG. 5A is a detection result when no liquid leakage is detected, and is a detection result when the detection signal and the background signal substantially match, so it is an example of a graph based on the detection signal, and the background It is also an example of a graph based on signals. Note that the detection signal is not limited to one based on the detection result in the height direction, and in this embodiment, a detection signal based on the detection result in the horizontal direction is also generated.

In S7, the signal processing unit 20 compares the detection signal and the background signal to determine whether the detection signal is an abnormal signal. That is, the signal processing unit 20 determines whether the detection signal and the background signal substantially match in S7, and if they substantially match (for example, when the detection signal corresponds to FIG. 5A), it is determined that there is no abnormality ( If there is a difference exceeding a preset threshold value (for example, if the detection signal corresponds to FIG. 5B or FIG. 5C), it is determined that there is an abnormality (Yes).

If it is determined in S7 that the detection signal is not abnormal (No), in S8, the light 30 is emitted to notify that it is normal, and the processes from S5 onwards are repeatedly executed. Note that when it is determined that there is no abnormality in S7, the step of notifying normality in S8 is not essential, and the processes from S5 onward may be repeated without notification.

If it is determined in S7 that the detection signal is abnormal (Yes), in S9 the signal processing unit 20 determines whether the abnormality is due to liquid leakage detection. In the case of an abnormality due to liquid leakage detection, blood 5 that has flowed down from the patient's forearm 4 accumulates on the sheet 34 placed under the forearm 4, so that the patient's forearm 4 in the background signal shown in FIG. A stronger reflected wave reaction than that of the forearm 4 occurs at a position farther from the receiving antenna 18 than the reaction (see FIGS. 5B and 5C). Therefore, for example, if the abnormality determination of the detection signal in S7 is due to the detection signal being stronger than the background signal at a position farther than the forearm 4, it is determined in S9 that the abnormality is due to liquid leakage (Yes). , if the abnormality is caused by another difference, it can be determined in S9 that the abnormality is not due to liquid leakage (No). In S9 of this embodiment, for example, if the detection signal exceeds a predetermined threshold at a position farther than the forearm 4 (reference position) by a predetermined distance from the forearm 4 (reference position), the detection signal detects leakage. Perform detection judgment.

An example of an abnormality other than liquid leakage determined in S9 is a case where the patient moves the forearm 4 and the forearm 4 moves out of the detectable range, causing the detection response of the forearm 4 to disappear. Such movement of the forearm 4 is detected, for example, based on detection signals of the Z-axis and an axis perpendicular to the forearm 4 placed on the seat 34, and the forearm 4 is detected to be out of a preset range within the detectable range. Alternatively, when the forearm 4 moves out of the detectable range, an abnormality other than liquid leakage is detected.

It is desirable that the amount of liquid leakage at which an abnormality is detected in S9 is, for example, 30 to 300 ml. By setting the leakage amount, which is the threshold for abnormality detection, to 30 ml or more, false detection due to patient sweating, etc. can be easily avoided. In addition, if the amount of liquid leakage is not a certain amount, for example, it is difficult to change the amount of millimeter wave reflection in the detection signal of the Z axis and the axis perpendicular to the forearm 4 placed on the seat, and the peak due to liquid leakage detection is difficult to become clear. .

Further, for example, when the abnormality of the detection signal in the determination in S7 continues for a predetermined determination time, the determination process in S9 may be performed. That is, a determination factor based on time may be added to the determination factor of abnormality of the detection signal. For example, if a medical worker temporarily blocks millimeter waves, or if a patient moves the forearm 4 out of the detectable range and then immediately returns it to the detectable range, Although the forearm 4 is no longer detected, there is no need to detect an abnormality in this case. Therefore, if the determination time is set in advance for a time that does not cause a major problem in fluid leakage, and if the abnormality determination in S7 continues beyond the determination time, the determination process in S9 is started. , it is possible to reduce the computational processing load and avoid unnecessary notifications. Note that the length of the above-mentioned determination time is not particularly limited, and is appropriately set depending on, for example, the expected leakage rate of the liquid to be detected, etc., but when detecting the leakage of blood 5 from the puncture site, is preferably within the range of 6 to 90 seconds.

If it is determined in S9 that there is an abnormality due to liquid leakage detection (Yes), the notification device 14 notifies the liquid leakage detection in S10. In this embodiment, as shown in FIG. 3, the lighting of the light 30 provided in the liquid detection device 10 and the sounding of a warning sound by the speaker 32 are respectively executed. It is desirable that the lighting of the light 30 and the sound of the speaker 32 at the time of liquid leakage detection are different from the lighting and sound of the speaker 32 to notify an error in S4 in the pattern, color, pitch, etc. of the light and sound. , it becomes possible to easily distinguish between the detection of liquid leakage and the occurrence of an error.

If it is determined in S9 that the abnormality is not due to liquid leakage detection (No), the notification device 14 notifies the occurrence of an error by emitting light and making a sound in S4. This notifies medical personnel, etc. that there is a possibility that effective monitoring of liquid leakage may not be possible. In addition, it is preferable that the light emission and sound emission of the notification device 14 in this case are different from the light emission and sound emission when liquid leakage is detected, and may be the same as the light emission and sound emission in S4, or the light emission and sound emission different from S4. It may be a pattern, a luminescent color, a musical pitch, etc.

In addition, if you want to interrupt monitoring of liquid leakage, such as when the patient goes to the toilet or when you want to add taping, the liquid detection device 10 is completely stopped, and when it is reused, the processes from S1 onwards are performed from the beginning. However, for example, the liquid leakage monitoring process may be temporarily stopped by operating a pause switch on the detection device main body 12. According to this, the processing at the time of restarting can be simplified compared to the case where the system is completely stopped and then restarted.

The detection results shown in FIGS. 5A, 5B, and 5C are based on the radar module "ST219-0003" manufactured by Sharp Takaya Electronics Co., Ltd. (currently Estakaya Electronics Co., Ltd.) as the signal processing section 20 of the detection device main body 12. This was obtained through a test in which the transmitting antenna 16 and the receiving antenna 18 were placed at a position approximately 50 cm vertically above a human body lying supine on a bed indoors to detect fluid leakage from the arm. It is something. As stated in the test results below, we have confirmed that by using millimeter waves indoors to monitor leaks of small amounts of liquid, it is possible to detect leaks with the accuracy level required in the medical field. Ta.

In addition, in the above detection test, simulated blood 5, which can obtain reflected waves equivalent to real blood, was used as the detection target liquid. 5B and 5C both show the detection results in a state where liquid leakage has occurred, but since the leakage amount in FIG. 5B is 100 ml and the leakage amount in FIG. 5C is 300 ml, FIG. 5C is better. However, the peak due to liquid leakage detection appears stronger and more clearly. The notification device 14 may issue a stronger warning by changing the color of the light 30 or increasing the output (sound pressure) of the speaker 32 as the amount of leakage increases. .

According to the liquid detection device 10 according to the present embodiment, leakage of blood 5 can be detected in a non-contact manner by transmitting millimeter waves from the liquid detection device 10 located at a distance from the patient. . This eliminates the need for medical personnel to attach the detection device to the patient, and the patient does not need to continue wearing the detection device, making it possible to move the forearm 4 etc. to a certain extent, making it possible for patients and medical personnel to This can reduce the burden on people.

Furthermore, by detecting the blood 5 using reflected waves of millimeter waves, for example, even if the blood 5 is covered with a bedding, etc., it can be monitored using visible light such as a camera as disclosed in Patent No. 6,534,316. Unlike the futon, it is possible to detect liquid inside the futon by penetrating it. In addition, millimeter waves can be transmitted over a certain range of areas where fluid leakage is expected to occur, so variations in detection results due to the flow direction of blood 5 are less likely to occur, and blood 5 is Stable and accurate detection is possible.

In this embodiment, since a liquid-impermeable sheet 34 is placed below the forearm 4 of the patient who is expected to leak, the blood 5 on the sheet 34 increases as the leak progresses. , more easily detected. As a result, blood 5 can be reliably detected before a large amount of liquid leaks, and the reliability of liquid detection is improved.

Blood 5 flowing out of the patient's forearm 4 flows below the forearm 4 and accumulates on the sheet 34, so the detection position of the blood 5 is slightly below the forearm 4. Further, it is assumed that the blood 5 flowing out from the forearm 4 will collect in the recess formed in the seat 34 by placing the forearm 4 without leaving the forearm 4 significantly. Therefore, by setting the range in which blood 5 can be detected by liquid detection device 10 using the position of forearm 4 as a reference, it becomes possible to limit the detection range and perform more accurate detection.

The liquid detection device 10 that detects the leakage of blood 5 automatically notifies the leakage detection using the light 30 and speaker 32 that are the notification device 14, so that the leakage can be detected without the need for medical personnel to continuously attend to the patient. When liquid occurs, it becomes possible to take immediate action. Although it is desirable that the notification device 14 notifies medical personnel of the occurrence of liquid leakage, for example, the patient may notify the medical personnel based on the warning light or sound of the notification device 14, or other notifications may be made. Leakage can also be dealt with by having people around the patient notify medical personnel based on warning lights and sounds.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited by the specific description. For example, in the embodiment described above, a case is described in which the leakage of blood 5 during artificial dialysis is detected, but for example, in the case of infusion, when the needle of the infusion circuit comes off from the patient's forearm 4, etc., and the drug solution etc. leaks. Additionally, it is also possible to detect a chemical liquid or the like as a liquid to be detected. In addition, fluid leakage from piping, fluid leakage from body cavity fluid, fluid leakage from discharge pipes, etc. that may occur during supply or cleaning of dialysate or dialysis water in a dialysate supply device or dialysis water preparation device can be detected as liquids to be detected. You can also do it. Preferably, the liquid to be detected is a bodily fluid existing in the human body, or a liquid such as a medicinal solution or a blood transfusion supplied to the human body from the outside. Further, in liquid detection using millimeter waves, since the detection accuracy is unlikely to be degraded by bedding or clothing, it can be suitably applied to, for example, detection of patient's urine.

For example, if one detection device main body 12 can be switched to a plurality of detection modes, multiple types of leakage with different leakage speeds and amounts of liquid to be detected can be detected in one detection device main body 12 by switching the detection mode. It is also possible to monitor. Specifically, for example, there is a detection mode that detects leakage of blood 5 from the punctured portion shown in the embodiment, a detection mode that detects leakage of an infusion whose leakage rate is slower than that of blood 5, and a detection mode that detects leakage of blood 5 from the punctured portion. By making it possible to switch between the detection mode that detects the leakage of the circuit cleaning fluid of the artificial dialysis machine 1, which has a faster leakage rate than the dialysis machine, one detection device main body 12 can handle the leakage of these three types of liquids to be detected. can do. Note that the plurality of detection modes may be different from each other in at least one of, for example, the amount of liquid to be detected for liquid leakage, the notification method when liquid leakage is detected, the threshold value for the duration of abnormality detection, and the like.

In the embodiment described above, an example was shown in which the detectable range of blood 5 is set based on the position of the forearm 4, which is a part of the patient's body. It is also possible to set the detectable range based on other than the standard. When the part that supports the forearm 4, such as the bed 7 or the seat 34, is used as the reference position for setting the detectable range, leakage is monitored based on the amount of millimeter wave reflection at approximately the same height as the reference position. , the position of the forearm 4 is monitored above the reference position.

Even when a part of the patient's body is used as the reference position, the reference position can be set according to the part where fluid leakage is expected to occur, and is not limited to the forearm 4, for example, near the leg. If fluid is assumed, the patient's legs may be the reference location. Also, for example, by placing a member with a high millimeter wave reflectance, such as aluminum foil, in advance around the reference part of the detectable range, it is possible to detect the reference position more accurately. You can also do it.

The light 30 and the speaker 32 are one aspect of the notification device 14, and in addition to or in place of the light 30 and the speaker 32, the notification device 14 can be used, for example, to notify a medical professional registered in advance when detecting a liquid leak or when an error occurs. Alternatively, a mobile device may be employed, and the control unit 22 may transmit and notify the notification.

In the embodiment described above, as an automatic response when the liquid detection device 10 detects a liquid leakage, it is exemplified that the light 30 and the speaker 32 notify the occurrence of a liquid leakage. At the time of detection, it is also possible to execute a response to prevent the progress of liquid leakage, such as stopping the artificial dialysis apparatus 1 connected by the external connection part 28 or activating a cutoff device of the infusion circuit. An example of stopping the artificial dialysis apparatus 1 is, for example, stopping a pump for circulating blood in a blood circuit. In this case, in addition to directly controlling and stopping the operation of the pump itself by a control device connected to the pump by wire or wireless, a control device connected to the pump by wire or wireless also controls a clamp that interrupts a part of the blood circuit. The pump can also be stopped by using the safety function of the artificial dialysis machine 1 that increases the pressure in the blood circuit and stops the circulation when the pressure increase is detected. Note that, for example, when a leak in the infusion circuit is detected, the infusion pump may be automatically stopped by the same control as described above.

The detection device main body 12 and the notification device 14 may be provided integrally. Further, an input unit for operating the liquid detection device 10 may be connected to the liquid detection device 10 by wire and extend from the liquid detection device 10, or may be connected wirelessly to the liquid detection device 10, It may be provided separately from the liquid detection device 10.

The liquid detection device 10 may be integrally assembled with other medical equipment such as the artificial dialysis device 1. Further, for example, as shown in FIG. 6, the detection device main body 12 can be installed in advance on the ceiling 8 of a medical facility. In this case, it is possible to reduce the risk of the liquid detection device 10 becoming defective due to application of external pressure or contact with liquid or the like. Further, the liquid detection device 10 may be a stand-alone device independent from other medical equipment, medical facilities, and the like.

As shown in FIG. 1, if radio wave shields 36, 36 with high or low millimeter wave reflectivity are attached to the patient's forearm 4, the position of the forearm 4 can be determined based on the reflected waves of the radio wave shield 36. It can be detected more clearly. In FIG. 1, radio wave shields 36 are attached to both sides of the forearm 4 in the length direction across the puncture site (blood collection port 2, blood return port 3) that requires monitoring of blood leakage. The radio wave shielding body 36 is made of a material with a millimeter wave reflectance higher or lower than that of the forearm 4. For example, a thin metal material (metal foil, film, tape, sheet, etc.) is used as a reflector with a high radio wave reflectance. (including thin plates), resin electromagnetic wave shielding films (films made of materials with high millimeter wave reflectance or absorption, such as flexible radio wave reflective films made by laminating a resin layer and a metal layer) ) etc. The manner in which the radio wave shield 36 is attached to the forearm 4 is not limited. For example, the radio wave shield 36 may be attached to the forearm 4 by being attached to the forearm 4, or it may be attached to the forearm 4 in an extrapolated state. It may be provided on the circumference or a part of the circumference, or it may be provided in advance on the sleeve of the patient's clothing, or it may be provided in advance on the sleeve of the patient's clothing, or for fixing indwelling devices (indwelling needles, dialysis circuits, etc.) on the skin. It may also be provided on medical tape. If such radio wave shields 36, 36 are attached to the forearm 4, the blood leakage detection target area (puncture site) of the forearm 4 located between the radio wave shields 36, 36 can be detected more accurately using reflected millimeter waves. can be monitored. Note that the radio wave shielding body 36 is not limited to the aspect in which it is provided on both sides of the blood leakage detection target area. For example, one radio wave shielding body 36 may be placed near the blood leakage detection target area to monitor the blood leakage detection target area. It is also possible to improve detection accuracy by narrowing the target range, or use it as a standard for setting the monitoring target range. In order to ensure good visibility, the radio wave shield 36 preferably has a minimum width dimension (minimum dimension in a direction orthogonal to the millimeter wave projection direction) of 1 cm or more when projected in the millimeter wave projection direction. More preferably, if the minimum width of the radio wave shield 36 is within the range of 2 to 5 cm, better visibility can be ensured while suppressing the patient's discomfort.

In the above embodiment, a beacon that transmits millimeter waves may be employed instead of or in addition to the radio wave shield 36. The detection device main body 12 receives the millimeter waves transmitted from the beacon, thereby making it possible to clearly grasp the position of the beacon. According to this, clearer millimeter waves can be stably received compared to the case of receiving reflected waves of millimeter waves, and the site to be monitored for blood leakage (puncture site) can be detected more accurately. Can be done. Note that the beacon may be one that transmits radio waves with a frequency other than millimeter waves to a sensor separate from the detection device main body 12, and separate from the monitoring of blood leakage by the detection device main body 12. Blood leakage may be monitored in combination with a sensor.

For example, if a metal body with a high millimeter wave reflectivity is embedded in the patient's forearm 4 in addition to the radio wave shield 36 with a high millimeter wave reflectance, the radio wave shield 36 may be After transmitting the waves and acquiring the reference information, the radio wave shield 36 is attached to the forearm 4 and leakage monitoring is started, and the reflected waves from metal bodies other than the radio wave shield 36 are detected as noise based on the reference information. You may also perform a process to remove it as In this way, the position of the radio wave shielding body 36 can be detected with high accuracy even if another metal object (such as a bolt) is embedded in the area to be detected for liquid leakage.

It is also possible to attach a radio wave shield to the connector of the indwelling needle (blood collection port 2 and blood return port 3) punctured in the forearm 4, the tube of the dialysis circuit connected to the indwelling needle, etc. According to this, when the indwelling needle is pulled out from the forearm 4, it becomes possible to detect by millimeter waves that the indwelling needle or the dialysis circuit is separated from the forearm 4 due to movement. Therefore, it is possible to detect needle dislodgement, which is the cause of liquid leakage, and it is possible to detect that liquid leakage has occurred due to needle dislodgement. Furthermore, if a radio wave shield is provided on each of the forearm 4 and a device such as a connector, it becomes possible to more reliably detect whether or not the forearm 4 and the device have separated. The radio wave shielding body can be used not only for detecting needle dislodgement but also for monitoring whether a detection target part is located within the monitoring target range. Note that the device itself, such as a connector, a puncture needle, or a circuit component (tube) made of metal or the like may be used as a radio wave shield.

The liquid detection device 10 can also be used by being attached to medical equipment other than the artificial dialysis device 1. Specifically, the detection device main body 12 can be attached to a support provided on the bed 7, for example.

In the embodiment described above, an example was shown in which the sheet 34 was used as a base member that prevents permeation of the liquid to be detected, but the base member is not essential. If there is no base member, the liquid to be detected will be absorbed into the bed below the forearm, but even in that case it can be detected because the amount of millimeter waves reflected changes. Furthermore, a waterproof mattress may be used in the bed instead of the base member. Further, the size of the base member is not particularly limited, and may be in the form of a bed pad that covers the entire bed, for example. Further, although the sheet 34 having a laminated structure having a nonwoven fabric layer and a resin film layer is illustrated as the base member, the structure of the base member is not particularly limited as long as it can restrict the permeation of the liquid to be detected. It may also be a resin sheet. Further, the base member may be a plate-like member instead of a sheet-like member. According to this, compared to a sheet-like base member, dents in the mattress of the bed 7 are less likely to affect the detection, and therefore more stable detection is possible. Further, by disposing a member such as aluminum foil with a high reflectance of millimeter waves as the base member, it is possible to simplify the process of positioning the patient's forearm within the monitoring target range.

In the embodiment described above, the detection signal is compared with the background signal, and when the amount of change in signal intensity at a predetermined position is larger than the threshold value, a liquid leak is detected. Liquid leakage may be detected when the absolute amount of the signal strength (the amount of millimeter wave reflection) of the detection signal is greater than a threshold value. In this way, detection of liquid leakage is not necessarily limited to comparison with the detection result (background signal) when no liquid leakage is detected.

10 Medical liquid detection device (first embodiment)
12 Detection device main body 14 Notification device 16 Transmission antenna (transmission section)
18 Receiving antenna (receiving section)
20 Signal processing section (detection section)
22 Control unit 24 Power supply 26 Switch 28 External connection unit 30 Light 32 Speaker 34 Seat (base member)
36 Radio wave shielding body 1 Artificial dialysis device 2 Blood collection port 3 Blood return port 4 Forearm 5 Blood (liquid subject to medical detection)
6 Pole 7 Bed 8 Ceiling

Claims

a transmitter that transmits millimeter waves as a transmission signal;
a receiving unit that receives a reflected wave of the transmitted signal as a received signal;
A medical liquid detection device comprising a detection unit that electrically detects a medical detection target liquid such as blood based on the received signal.
comprising a base member that restricts passage of the medical detection target liquid;
The medical liquid detection device according to claim 1, wherein the transmitting section is arranged above the base member, and the transmitting signal is transmitted from above toward the base member.
The medical liquid detection device according to claim 1 or 2, wherein the detectable range of the medical detection target liquid is set based on the position of the patient's body.
The medical liquid detection device according to claim 1 or 2, further comprising a notification device that notifies the detection of the medical detection target liquid by the detection unit.