JP7474232B2 - Leak detection device - Google Patents

Description

The present invention relates to a leakage detection device that detects leakage of injected fluid outside a blood vessel.

A leakage detection device that detects when an injection fluid that is to be injected into a blood vessel leaks out of the blood vessel has been known (see Patent Document 1).

This leakage detection device includes multiple thermocouples attached around the puncture site of the injection needle through which the injection fluid is injected, and a determination unit that determines whether the injection fluid has leaked outside the blood vessel based on the temperatures (body surface temperatures) obtained from the multiple thermocouples.

This determination unit repeatedly samples the body surface temperature at the location where the thermocouple is attached in advance to calculate the average body surface temperature, and each time it samples the real-time body surface temperature, it calculates the amount of variation from the average body surface temperature, and checks whether the body surface temperature deviates from the normal temperature depending on whether the amount of variation exceeds a threshold, and if it does deviate, it determines that leakage of the injected fluid has occurred outside the blood vessels.

International Publication No. WO2017/179228

The leakage detection device determines whether or not there is extravasation based on the amount of variation in the body surface temperature around the puncture site from a previously calculated average body surface temperature (i.e., a constant value). Therefore, even if the temperature on the body surface fluctuates (especially decreases) over a wide range due to changes in the surrounding temperature or stress, the amount of variation will be large, and there is a concern that this may result in a false positive, i.e., a false positive, in which case the device may determine that there is leakage of the injected fluid outside the blood vessel when there is no leakage.

Therefore, the objective of the present invention is to provide a leakage detection device that can accurately detect leakage of injection fluid outside the blood vessel.

The leakage detection device of the present invention comprises:
A leakage detection device for detecting leakage of an injection liquid injected into a blood vessel outside the blood vessel,
a device body capable of detecting the leakage based on the body temperature around a puncture part of a syringe needle for injecting the injection solution;
The device body includes:
an input unit to which body temperature information, which is a signal corresponding to the body temperature, is input;
a storage unit capable of storing the body temperature information input to the input unit;
a reference temperature derivation unit that derives a reference temperature over time, which is an average body temperature from a first reference time a certain time before the current time to a second reference time that is a first hour after the first reference time and before the current time, based on the body temperature information stored in the storage unit;
The device has a judgment unit that judges that the leakage has occurred when the current body temperature based on the body temperature information at the current time is lower than a threshold temperature that is set lower than the reference temperature based on the reference temperature for a second consecutive hour that is less than the first hour.

With this configuration, even if the body temperature changes over a wide area of the body surface, including the area around the puncture site, due to changes in the surrounding temperature or stress, the average body temperature (reference temperature) for the first hour, which is set based on the current time, is used. In other words, by making a judgment about leakage based on a threshold temperature that is based on a reference temperature that changes in conjunction with changes in body temperature over a wide area of the body surface, the influence of changes in body temperature over the wide area of the body surface on the judgment of the presence or absence of leakage (leakage of injection fluid) is suitably suppressed, and leakage can be detected with high accuracy.

In the liquid leakage detection device,
The second reference time may be earlier than the current time.

If leakage has already occurred at the current time, the body temperature around the puncture site has also begun to drop due to the leakage. For this reason, as in the above configuration, by deriving the threshold temperature (reference temperature) that serves as the criterion for determining leakage without excluding the body temperature at the current time (i.e., by finding the average body temperature between the first reference time and the second reference time), the influence of the drop in body temperature caused by leakage that has already occurred at the current time can be avoided when determining whether or not leakage has occurred, and leakage can be detected more accurately.

In addition, in the liquid leakage detection device,
The device body may be capable of changing the length of the second period of time.

When detecting leakage, there is a trade-off between the accuracy of leakage detection and the shortness of the time from when leakage occurs to when it is detected, but the above configuration makes it possible to adjust the balance between the accuracy of leakage detection and the early detection of leakage (the length of time from when leakage occurs to when it is detected). The details are as follows.

In detecting leakage, lengthening the second time improves the detection accuracy of leakage, but lengthens the time from leakage occurrence to detection. In contrast, shortening the second time shortens the time from leakage occurrence to detection, but decreases the detection accuracy of leakage. Therefore, by making the length of the second time variable as in the above configuration, the leakage detection device can be used in both cases where emphasis is placed on leakage detection accuracy and where emphasis is placed on early detection of leakage.

In addition, in the liquid leakage detection device,
The determination unit also determines that the leakage has occurred when the current body temperature is lower than a body temperature based on the body temperature information at a third reference time that is before the current time and after the second reference time by a first temperature or more,
The first temperature may be greater than a difference between the reference temperature and the threshold temperature.

When the amount of leakage per unit time is large, the body temperature of some areas around the puncture site drops significantly in a short period of time. For this reason, as in the above configuration, by determining that leakage has occurred when a large drop in body temperature (greater than the first temperature) is detected in the short period of time between the third reference time and the current time, it is possible to detect leakage with a large amount of leakage per unit time early (i.e., without the second time having passed).

In this case, in the leakage detection device,
The determination unit may determine that a detection error has occurred when the current body temperature has dropped by at least a second temperature that is greater than the first temperature from a body temperature based on the body temperature information at the third reference time.

When using the leakage detection device, if a sensor or the like that detects temperature (body temperature) detects an ambient temperature such as room temperature, the ambient temperature is sufficiently low compared to body temperature, so the detected temperature drops more than the temperature drop caused by leakage. For this reason, as in the above configuration, a second temperature that is greater than the first temperature is set as a threshold value, and if the detected temperature (temperature based on body temperature information) drops more than this value in a short period of time, it is determined to be a detection error, making it possible to detect that the sensor or the like is not properly detecting body temperature around the puncture site.

The liquid leakage detection device further includes a temperature detection unit having a heat-sensing element capable of detecting the body temperature and outputting the body temperature information, and removably fixing the heat-sensing element to the periphery of the puncture portion;
The heat sensitive element may be connected to the input section of the device body.

This configuration makes it easy to attach and remove the heat-sensing element that detects body temperature around the puncture area.

In addition, in the liquid leakage detection device,
the temperature detection unit has a plurality of the heat-sensitive elements and a sheet-like holder that holds the plurality of heat-sensitive elements and can be attached to the periphery of the puncture portion;
The determination unit may make a determination regarding the leakage for each of the body temperature information from the heat sensitive element.

When leakage occurs, the location (area) where a drop in body temperature (a drop in body temperature caused by leakage) occurs around the puncture site is not constant. However, as in the above configuration, leakage can be detected over a wide area by determining leakage for each body temperature (body temperature information) detected at multiple locations around the puncture site, making it possible to detect leakage more reliably.

In addition, in the liquid leakage detection device,
The reference temperature derivation unit may, when the body temperatures detected by a majority of the multiple heat-sensing elements drop by a third temperature or more during a common third time period, erase the previous reference temperatures corresponding to each of the multiple heat-sensing elements, and determine each reference temperature from the body temperature information corresponding to each of the multiple heat-sensing elements thereafter.

In this way, when the body temperature detected by the majority of the multiple heat-sensitive elements drops significantly (above the third temperature) within a predetermined time (a common third time), the reference temperatures corresponding to each of the multiple heat-sensitive elements are re-derived (i.e., reset), thereby reducing the effect of a drop in overall body temperature due to a drop in ambient temperature, etc., on leakage detection, thereby further improving the accuracy of leakage detection.

As described above, the present invention provides a leakage detection device that can accurately detect leakage of injection fluid outside the blood vessel.

FIG. 1 is a diagram showing an attached state of a temperature detection unit provided in a leakage detection device according to the present embodiment. FIG. 2 is a diagram showing the configuration of the leakage detection device. FIG. 3 is a diagram showing a configuration of the temperature detection unit. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. FIG. 5 is a functional block diagram of a main body of the liquid leakage detection device. FIG. 6 is a functional block diagram of a determination unit in the calculation unit provided in the device main body. FIG. 7 is a diagram showing an example of a change in body temperature over time detected by one temperature sensor around the puncture site, and a change in the reference temperature associated with the change in body temperature. FIG. 8 is a diagram showing another example of the change in body temperature over time detected by one temperature sensor around the puncture site, and the change in reference temperature associated with the change in body temperature. FIG. 9 is a flow diagram of leakage detection by the leakage detection device. FIG. 10 is a flow diagram of leakage detection in the first mode. FIG. 11 is a flow diagram of leakage detection in the second mode. FIG. 12 is a flow diagram of leakage detection in the third mode. FIG. 13 is a flow diagram of leakage detection in the fourth mode. FIG. 14 is a diagram for explaining a temperature detection unit according to another embodiment. FIG. 15 is a diagram for explaining a temperature detection unit according to another embodiment.

One embodiment of the present invention will be described below with reference to Figures 1 to 13.

As shown in FIG. 1, the leakage detection device according to this embodiment is used to detect leakage of an injection liquid, such as an anticancer drug, that is to be injected into a blood vessel Bv in the arm or the like, outside the blood vessel Bv (hereinafter also referred to as "leakage"), and is used together with an infusion device 100 that injects the injection liquid into the blood vessel Bv. Below, a brief description of the infusion device 100 will be given, followed by a detailed description of the leakage detection device 1.

This drip infusion device 100 has a container (not shown) that contains the injection fluid, and an infusion set 110 that carries the injection fluid from the container to the patient through equipment such as an infusion pump (not shown) and an infusion controller (not shown). The infusion set 110 has a patient line 111 (between the above equipment and the patient) that serves as a flow path for the injection fluid, and a syringe 112 connected to the tip of the patient line 111, and the injection fluid is injected into the patient's blood vessel Bv by puncturing the blood vessel Bv with an injection needle 113. At this time, the syringe 112 and the tip side portion of the patient line 111 are fixed with tape 115 so as to be aligned with the patient's body surface.

2, the leakage detection device 1 includes a device main body 2 that detects leakage of the injection fluid out of the blood vessel Bv based on the body temperature (body surface temperature) around the puncture site of the injection needle 113 that injects the injection fluid. The leakage detection device 1 of this embodiment includes a temperature detection unit 3 that is attached around the puncture site on the body surface of a patient, etc., and a cable 4 that connects the device main body 2 and the temperature detection unit 3.

As shown in Figures 3 and 4, the temperature detection unit 3 has a temperature sensor (thermal element) 32 that detects body temperature and outputs a signal (body temperature information) corresponding to the body temperature, and is configured to removably fix the temperature sensor 32 around the puncture site. The temperature detection unit 3 of this embodiment has multiple temperature sensors 32 and a sheet (holding unit) 31a that holds the multiple temperature sensors 32 and can be attached around the puncture site.

Specifically, the temperature detection unit 3 has a sheet portion 31 and a plurality of temperature sensors (thermal elements) 32 arranged on the sheet portion 31. The temperature detection unit 3 also has a connector 33 to which the cable 4 and the device main body 2 are connected. The cable 4 is connected to the connector 33 in this embodiment.

The sheet portion 31 is a sheet-like member having a sheet 31a that is attached to the area around the puncture site of a patient's blood vessel Bv punctured by the injection needle 113, and a release sheet 311d that can be peeled off from the sheet 31a.

The sheet 31a may be translucent. In this embodiment, the sheet 31a is translucent and therefore translucent. This allows observation of color changes, etc., at the site on the body surface where the sheet 31a is attached, when the sheet 31a is attached around the puncture site.

The sheet 31a may have a guideline 312 that extends vertically through the center of the rectangular sensor arrangement section 311 in which the multiple temperature sensors 32 are arranged. The guideline 312 is used to position the sheet 31a when attaching the sheet 31a to the periphery of the puncture site. Specifically, the sheet 31a is attached to the periphery of the puncture site so that the guideline 312 overlaps with the injection needle 113 inserted into the blood vessel Bv.

In the sheet 31a of this embodiment, a protective film 311a, a temperature sensor film 311b, and an adhesive sheet 311c are laminated in this order. A release sheet 311d is laminated on the sheet 31a so as to face the adhesive sheet 311c, and when the sheet 31a is attached to the periphery of the puncture site, the sheet 31a is attached so that the release sheet 311d is peeled off from the adhesive sheet 311c and the adhesive sheet 311c comes into contact with the periphery of the puncture site (body surface).

The temperature sensors 32 are arranged at intervals in the direction in which the sheet 31a extends in the sensor arrangement section 311 of the sheet 31a. Each of the temperature sensors 32 is arranged on the temperature sensor film 311b of the sheet 31a, and faces the periphery of the puncture site (body surface) via the adhesive sheet 311c when the sheet 31a is attached to the periphery of the puncture site. In the sheet 31a of this embodiment, the temperature sensors 32 are arranged in a lattice pattern. More specifically, the temperature sensors 32 are arranged in a line in the direction in which the guide line 312 extends and in a direction perpendicular to the direction in which the guide line 312 extends. Each temperature sensor 32 is electrically connected to the connector 33 and outputs a signal (body temperature information) corresponding to the detected body temperature.

5, the device body 2 has an input unit 21 to which body temperature information is input, a calculation unit 22 connected to the input unit 21, an alarm unit 23 connected to the calculation unit 22, and an operation unit 24 for operating the device body 2. The device body 2 also has a display unit 25 that displays the body temperature information input to the input unit 21. In the device body 2 of this embodiment, the input unit 21 is an input terminal to which the cable 4 is connected.

The calculation unit 22 is composed of a microcomputer that includes, for example, a CPU (Central Processing Unit), non-volatile memory elements such as a ROM (Read Only Memory) or an EEPROM (Electrically Erasable Programmable Read Only Memory) that store in advance various programs executed by the CPU and data necessary for their execution, and volatile memory elements such as a RAM (Random Access Memory) that serves as the so-called working memory of the CPU, and its peripheral circuits, etc.

When the calculation unit 22 executes a predetermined program, the calculation unit 22 is functionally configured to include a reference temperature derivation unit 221 and a judgment unit 222. The calculation unit 22 also has a memory unit 223 that can store body temperature information input over time from each temperature sensor 32 to the input unit 21.

The reference temperature derivation unit 221 derives a reference temperature T for each piece of body temperature information corresponding to each temperature sensor 32 stored in the memory unit 223 (see FIG. 7). This reference temperature T is the average body temperature for a predetermined time (first time t1) before the current time t10. FIG. 7 is a graph showing an example of a case where injection fluid gradually leaks out of the blood vessel Bv, and shows an example of a change over time in body temperature (more specifically, body surface temperature) detected by one temperature sensor 32 (e.g., the first temperature sensor 32a shown in FIG. 1) around the puncture site, and a change in the reference temperature T with a change in body temperature. In this graph, the horizontal axis is time and the vertical axis is body temperature, and the time when leakage started on the horizontal axis is set to 0 seconds.

More specifically, the reference temperature derivation unit 221 derives a reference temperature T, which is the average body temperature over time, for each piece of body temperature information corresponding to each temperature sensor 32, based on the body temperature information over time stored in the memory unit 223. The reference temperature T is the average body temperature over time from a first reference time t11, which is a certain time before the current time t10, to a second reference time t12, which is a time a first time t1 after the first reference time t11 and before the current time t10. In this embodiment, the second reference time t12 is before the current time t10.

For example, when focusing on the body temperature information input to the calculation unit 22 over time from one temperature sensor (first temperature sensor) 32a of the temperature detection unit 3 (see Figures 1 and 7), the reference temperature derivation unit 221 of this embodiment derives the average body temperature for 60 seconds (first time t1) from a first reference time t11, 180 seconds ago (a certain time ago), to a second reference time t12, 120 seconds before the current time t10 (after the first reference time t11), as the reference temperature T at the current time t10, when the current time t10 is set to 0 seconds in Figure 7. When the body temperature changes over time, this reference temperature T changes in the same way with a predetermined time delay relative to the change in body temperature (see Figure 7). The reference temperature derivation unit 221 derives this reference temperature T over time (continuously or intermittently) for each body temperature information input from each temperature sensor 32.

In addition, in the leakage detection device 1, the interval between the current time t10 and the first reference time t11 when detecting leakage is preferably 1 to 300 seconds, more preferably 120 to 180 seconds. If the interval between the current time t10 and the first reference time t11 exceeds 300 seconds, there is a disadvantage that when the temperature change of the body surface becomes large, the difference between the temperature at the current time t10 and the reference temperature T becomes large, and leakage is falsely detected. In addition, if the interval between the current time t10 and the first reference time t11 is less than 1 second, when the injection liquid starts to leak out of the blood vessel and the temperature has already dropped, the difference between the temperature at the current time t10 and the reference temperature T is small, so there is a disadvantage that the detection accuracy of leakage decreases. In addition, the first time t1, which is the interval between the first reference time t11 and the second reference time t12, is preferably 10 to 300 seconds, more preferably 60 to 180 seconds. If the first time t1, which is the interval between the first reference time t11 and the second reference time t12, exceeds 300 seconds, the time required to calculate the average temperature (reference temperature T) during that time will be longer, and the detection start time will be delayed. Also, if the first time t1, which is the interval between the first reference time t11 and the second reference time t12, is less than 10 seconds, the time required to obtain the average temperature (reference temperature T) during that time will be shorter, and the accuracy of the reference temperature T will be reduced.

In addition, when the body temperatures detected by the majority of the temperature sensors 32 among the multiple temperature sensors 32 drop by a predetermined temperature (third temperature) or more during a common predetermined time (third time), i.e., when the body temperatures detected by the majority of the temperature sensors 32 drop significantly all at once in a short period of time, the reference temperature derivation unit 221 erases the previous reference temperatures T corresponding to each of the multiple temperature sensors 32 and determines each reference temperature T (reference temperature T corresponding to each temperature sensor 32) from the body temperature information input from each of the multiple temperature sensors 32 thereafter. In other words, each reference temperature T corresponding to the body temperature information input from each temperature sensor 32 is reset.

In this embodiment, when the body temperatures detected by 80% or more of the multiple temperature sensors 32 drop by 2°C (third temperature) or more within 2 seconds (common third time), the reference temperature derivation unit 221 erases the reference temperatures T corresponding to the previous temperature sensors 32 and calculates the reference temperatures T from the body temperature information input from each temperature sensor 32 thereafter.

In the leakage detection device 1, the common third time is preferably 1 to 20 seconds, and more preferably 1 to 3 seconds. The third temperature is preferably 1 to 6°C, and more preferably 2 to 6°C. If the common third time exceeds 20 seconds, there is a disadvantage that leakage of the injection liquid outside the blood vessel will not be detected until it occurs over a wide area. If the third temperature exceeds 6°C, there is a disadvantage that even if peeling from the body surface occurs and some temperature sensors 32 detect an ambient temperature such as room temperature and the temperature detected by the temperature sensors 32 drops significantly, this is determined to be leakage of the injection liquid outside the blood vessel (false detection). If the third temperature is less than 1°C, there is a disadvantage that a temperature change due to a change in physical condition will be erroneously recognized as leakage.

The judgment unit 222 judges the presence or absence of leakage by comparing the current body temperature based on the body temperature information at the current time t10 with the threshold temperature T1 for each body temperature information input from each temperature sensor 32. This threshold temperature T1 is a value that the judgment unit 222 sets lower than the reference temperature T based on the reference temperature T, and is set for each body temperature information input from each temperature sensor 32. Similarly to the reference temperature T, the threshold temperature T1 changes similarly when the body temperature changes over time, but with a predetermined time delay from the change. The threshold temperature T1 of this embodiment is set to a predetermined temperature (for example, 1°C) lower than the reference temperature T. In addition, in the leakage detection device 1, the threshold temperature T1 is preferably set to 0.25 to 6.0°C lower than the reference temperature T, and more preferably set to 0.5 to 2.0°C lower. If the difference between the threshold temperature T1 and the reference temperature T is set to more than 6.0°C, there is a disadvantage in that the detection accuracy decreases when a small amount of injection liquid leaks. Furthermore, if the difference between the threshold temperature T1 and the reference temperature T is set to less than 0.25°C, there is a disadvantage in that it is easier for erroneous detections to occur.

Specifically, as shown in FIG. 6, the judgment unit 222 has multiple algorithms (leakage detection algorithms) for judging the presence or absence of leakage, and changes the leakage detection algorithm to be used by switching the leakage detection mode by operating the operation unit 24 of the device main body 2. The judgment unit 222 of this embodiment has first to fifth algorithms A1 to A5 as multiple leakage detection algorithms. Of these first to fifth algorithms A1 to A5, the first to third algorithms A1 to A3 are algorithms for detecting gradual leakage of the injection fluid from the blood vessel Bv, and the fourth and fifth algorithms A4 and A5 are algorithms for detecting sudden leakage of the injection fluid from the blood vessel Bv. Specifically, they are as follows.

The first algorithm A1 is the algorithm with the highest sensitivity to detect leakage among the first to third algorithms A1 to A3, and for each piece of body temperature information input from each temperature sensor 32, it compares the current body temperature based on the body temperature information at the current time t10 with the threshold temperature T1 corresponding to the body temperature information, and determines that leakage has occurred when, in the body temperature information input from one temperature sensor 32, the current body temperature based on the body temperature information at the current time t10 is lower than the threshold temperature T1 continuously for a second time t2, which is a time less than the first time t1. The first algorithm A1 of this embodiment determines that leakage has occurred when, in the body temperature information input from one of the multiple temperature sensors 32, the body temperature at the current time t10 is lower than the threshold temperature T1 continuously for 10 seconds (second time t2).

The second algorithm A2 determines that leakage has occurred when, in body temperature information input from one of the multiple temperature sensors 32 (e.g., the first temperature sensor 32a: see FIG. 1), the current body temperature based on the body temperature information at the current time t10 is lower than the threshold temperature T1a corresponding to the body temperature information input from the first temperature sensor 32a for a second consecutive time t2 (see the range indicated by t2 in FIG. 7), and, in body temperature information input from the second temperature sensor 32b (see FIG. 1) adjacent to the first temperature sensor 32a, the current body temperature based on the body temperature information at the current time t10 is lower than the threshold temperature T1b corresponding to the body temperature information input from the second temperature sensor 32b.

In the second algorithm A2 of this embodiment, the second time t2 is 30 seconds. This second time t2 is preferably 10 to 60 seconds, and more preferably 20 to 40 seconds. If the second time t2 exceeds 60 seconds, there is a disadvantage that the time until leakage is detected becomes longer. Also, if the second time t2 is less than 20 seconds, there is a disadvantage that the sensitivity becomes closer to the first algorithm A1, and the difference between the first algorithm A1 and the second algorithm A2 becomes smaller. Also, in the temperature detection unit 3, the second temperature sensor 32b adjacent to the first temperature sensor 32a is a plurality of temperature sensors 32b (four in the example shown in FIG. 1) arranged around the first temperature sensor 32a, and in the second algorithm A2, if the body temperature at the current time is lower than the corresponding threshold temperature T1b in the body temperature information input from at least one of the plurality of second temperature sensors 32b, it is determined that leakage has occurred.

On the other hand, in the second algorithm A2, even if the current body temperature based on the body temperature information at the current time t10 input from the first temperature sensor 32a is lower than the threshold temperature T1a for 30 consecutive seconds (second time t2), if the current body temperature based on the body temperature information at the current time t10 input from the second temperature sensor 32b is the same as or higher than the threshold temperature T1b, it is determined that there is no leakage.

The third algorithm A3 is the algorithm with the lowest sensitivity to detect leakage among the first to third algorithms A1 to A3, and is the same as the second algorithm A2, except that the second time t2 is 60 seconds. In this third algorithm A3, the second time t2 is preferably 40 to 90 seconds, and more preferably 50 to 70 seconds. If the second time t2 exceeds 90 seconds, the temperature of the leaked liquid approaches body temperature, and the body temperature becomes higher than the threshold temperature T, which is a disadvantage in that the accuracy of leakage detection decreases. In addition, if the second time t2 is less than 50 seconds, the sensitivity becomes closer to that of the second algorithm A2, and the difference between the second algorithm A2 and the third algorithm A3 becomes smaller.

The fourth algorithm A4 is an algorithm with a higher sensitivity for detecting leakage than the fifth algorithm A5, and determines that leakage has occurred when, in the body temperature information input from one of the temperature sensors 32, the current body temperature is lower than the body temperature based on the body temperature information at a third reference time t13 before the current time t10 and after the second reference time t12 by a first temperature (first threshold) T11 or more (see FIG. 8). Note that FIG. 8 is a graph showing an example of a case where a large amount of injection fluid has leaked out of the blood vessel Bv, and shows an example of a change over time in body temperature (more specifically, body surface temperature) detected by one temperature sensor 32 (e.g., the first temperature sensor 32a shown in FIG. 1) around the puncture site, and a change in the reference temperature T with a change in body temperature. In this graph, the horizontal axis is time and the vertical axis is body temperature, and the time when leakage began on the horizontal axis is set to 0 seconds.

Furthermore, the fourth algorithm A4 judges that a detection error has occurred when, in the body temperature information input from one of the multiple temperature sensors 32 (for example, the first temperature sensor 32a: see FIG. 1), the current body temperature has dropped by a second temperature (second threshold) T12 or more, which is greater than the first temperature T11, from the body temperature based on the body temperature information at the third reference time t13. That is, the fourth algorithm A4 of this embodiment judges that a leak has occurred when the current body temperature has dropped by the first temperature (first threshold) T11 or more and less than the second temperature T12 from the body temperature based on the body temperature information at the third reference time t13, and judges that a detection error has occurred when the current body temperature has dropped by the second temperature T12 or more.

In the fourth algorithm A4 of this embodiment, the third reference time t13 is 10 seconds before the current time t10, the first temperature T11 is 0.6°C when the current body temperature drops by 3°C in 50 seconds, and the second temperature T12 is 6°C. In addition, in the fourth algorithm A4, the third reference time t13 is preferably 1 to 10 seconds before the current time t10, and more preferably 5 to 15 seconds before. If the third time t13 is within the range of 1 to 10 seconds before the current time t10, there is an advantage in that leakage can be detected earlier.

The fifth algorithm A5 is an algorithm with a lower sensitivity for detecting leakage than the fourth algorithm A4, and similarly to the fourth algorithm A4, it is determined that leakage has occurred when, in body temperature information input from one of the multiple temperature sensors 32, the current body temperature is lower by a first temperature (first threshold) T11 or more than the body temperature based on the body temperature information at a third reference time t13 that is before the current time t10 and after the second reference time t12. In the fifth algorithm A5 of this embodiment, the third reference time t13 is 10 seconds before the current time t10, similarly to the fourth algorithm A4, and the first temperature T11 is 0.6°C.

The fifth algorithm A5 determines that a detection error has occurred when the current body temperature is lower than the body temperature based on the body temperature information at the third reference time t13 by the second temperature T12 or more in each of the body temperature information input from two or more of the multiple temperature sensors 32. In the fifth algorithm A5 of this embodiment, the second temperature T12 is 6°C, as in the fourth algorithm A4.

In other words, the fifth algorithm A5 of this embodiment determines that leakage has occurred when, in the body temperature information input from one of the multiple temperature sensors 32, the current body temperature is equal to or higher than the first temperature (first threshold value) T11 and lower than the second temperature T12 compared to the body temperature based on the body temperature information at the third reference time t13, and determines that a detection error has occurred when, in each of the body temperature information input from two or more of the multiple temperature sensors 32, the current body temperature is equal to or higher than the second temperature T12 compared to the body temperature based on the body temperature information at the third reference time t13.

In addition, in the fifth algorithm A5, the third reference time t13 is the time set in the second algorithm A2 and the third algorithm A3. It may also be set individually.

The judgment unit 222 has the above-mentioned leakage detection algorithms (first to fifth algorithms A1 to A5), and the detection mode (first to sixth modes M1 to M6) is switched by operating the operation unit 24, thereby switching the leakage detection algorithms A1 to A5 used by the judgment unit 222 to judge leakage detection (see Figure 6).

Specifically, when the detection mode is switched to the first mode M1 by operating the operation unit 24, the judgment unit 222 judges whether or not there is a leak using the first algorithm A1.

When the detection mode is switched to the second mode M2 by operating the operation unit 24, the judgment unit 222 judges the presence or absence of leakage using the first algorithm A1 and the fourth algorithm A4. In this second mode M2, when the leakage condition is satisfied in one of the first algorithm A1 and the fourth algorithm A4, the judgment unit 222 judges that leakage has occurred.

When the detection mode is switched to the third mode M3 by operating the operation unit 24, the judgment unit 222 judges whether or not there is a leak using the second algorithm A2.

When the detection mode is switched to the fourth mode M4 by operating the operation unit 24, the judgment unit 222 judges the presence or absence of leakage using the second algorithm A2 and the fifth algorithm A5. In this fourth mode M4, when the leakage condition is satisfied in one of the second algorithm A2 and the fifth algorithm A5, the judgment unit 222 judges that leakage has occurred.

In addition, when the detection mode is switched to the fifth mode M5 by operating the operation unit 24, the judgment unit 222 judges whether or not there is a leak using the third algorithm A3.

When the detection mode is switched to the sixth mode M6 by operating the operation unit 24, the judgment unit 222 judges the presence or absence of leakage using the third algorithm A3 and the fifth algorithm A5. In this sixth mode M6, when the leakage condition is satisfied in one of the third algorithm A3 and the fifth algorithm A5, the judgment unit 222 judges that leakage has occurred.

The determination unit 222 determines whether or not there is a leak using algorithms A1 to A5 corresponding to the leak detection modes M1 to M6 selected by operating the operation unit 24 as described above, and if it determines that there is a leak, it outputs a leak signal to the alarm unit 23. In addition, if the determination unit 222 determines that there is a detection error, it outputs an error signal to the alarm unit 23.

When the leakage signal is input from the judgment unit 222, the alarm unit 23 outputs an alarm to the outside. Specifically, the alarm unit 23 outputs an alarm to the outside by sound, display, etc. in response to the input of the leakage signal. The alarm unit 23 in this embodiment has at least a speaker, and outputs an alarm sound to the outside in response to the input of the leakage signal. In addition, the alarm unit 23 outputs an error sound (a sound different from the alarm sound) to the outside in response to the input of an error signal.

The display unit 25 displays the body temperature and changes in body temperature around the puncture site based on the body temperature information input from each temperature sensor 32 to the device body 2. Specifically, the display unit 25 has multiple squares 251 arranged in a manner corresponding to the arrangement of the multiple temperature sensors 32 on the sheet 31a, and each square 251 displays the body temperature detected by the corresponding temperature sensor 32 using a color gradation. Note that the display of the display unit 25 in FIG. 2 corresponds to the leakage state in FIG. 1. In addition, each square 251 of the display unit 25 displays the temperature difference between a reference value (reference temperature T in this embodiment) and the body temperature detected by the temperature sensor 32 using a color gradation corresponding to the temperature difference, by operating the display switch button of the operation unit 24.

The display unit 25 of this embodiment has a 2-inch screen, and multiple squares 251 are arranged in rows of 5 squares each. Each square 251 of the display unit 25 displays the current body temperature every 25 seconds.

Next, we will explain how the leakage detection device 1 detects leakage, with reference to Figure 9.

First, the temperature detection unit 3 is attached around the puncture site of the patient's blood vessel Bv where the injection needle 113 of the infusion set 110 in the drip device 100 is inserted (see FIG. 1). At this time, the temperature detection unit 3 (more specifically, the sheet 31a) is attached so that the guide line 312 of the sheet 31a overlaps with the injection needle 113 inserted into the blood vessel Bv. More specifically, the sheet 31a is attached around the puncture site on the body surface so that the tip 113a of the injection needle 113 overlaps with the center of the sensor arrangement section 311 or with the temperature sensor 32c (see FIG. 3) located at the center of the multiple temperature sensors 32 arranged in a lattice pattern.

Next, the temperature detection unit 3 (more specifically, the connector 33) and the device body 2 (more specifically, the input terminal) are connected by the cable 4. Note that the connection between the temperature detection unit 3 and the device body 2 by the cable 4 may be performed before the temperature detection unit 3 is attached to the area around the puncture site.

When the injection needle 113 of the drip device 100 is inserted into the blood vessel and the temperature detection unit 3 of the leakage detection device 1 is attached to the area around the puncture site, leakage detection by the leakage detection device 1 begins, and the injection of the injection fluid into the blood vessel Bv begins.

Specifically, the leakage detection mode M1 to M6 is selected by operating the operation unit 24 of the device main body 2 (step S1), and the start button (not shown) of the operation unit 24 is pressed.

The determination unit 222 detects leakage using algorithms A1 to A5 corresponding to the selected leakage detection mode (first to sixth modes M1 to M6) (step S2). The determination unit 222 continues to detect leakage until it determines that leakage has occurred (step S3: No). When the determination unit 222 determines that leakage has occurred, i.e., when leakage has been detected (step S3: Yes), it outputs a leakage signal to the alarm unit 23 (step S4). The alarm unit 23, to which the leakage signal has been input, outputs an alarm sound from the speaker (step S5) to notify people in the vicinity (doctors, nurses, etc.) that leakage has occurred.

The determination of the presence or absence of leakage by the determination unit 222 differs for each selected leakage detection mode M1 to M6. Specifically, it is as follows.

Normally, the temperature of the injection fluid injected into the blood vessel Bv is lower than body temperature, so when leakage occurs, the body temperature of a portion of the area around the puncture site (first area Ar1 in the example shown in Figure 1) drops first. The first mode M1 uses the first algorithm A1 to detect the occurrence of leakage based on this drop in body temperature.

Specifically, as shown in FIG. 10, the reference temperature derivation unit 221 derives a reference temperature T for each piece of body temperature information from each temperature sensor 32 stored in the memory unit 223 (step S11).

Once the reference temperature T is derived for each piece of body temperature information, the judgment unit 222 compares the current body temperature based on the body temperature information at the current time t10 with the threshold temperature T1 corresponding to the body temperature information for each piece of body temperature information input from each temperature sensor 32 (step S12).

Then, when the current body temperature based on the body temperature information at the current time t10 input from the temperature sensor 32 (first temperature sensor 32a: see Figure 1) at a position corresponding to the area Ar1 where the temperature first decreased around the puncture area is lower than the threshold temperature T1 (more specifically, the threshold temperature T1a corresponding to the body temperature information input from the first temperature sensor 32a) for 10 consecutive seconds (second time t2) (Step S13: Yes), the judgment unit 222 judges that a leak has occurred (Step S14).

On the other hand, in step S13, if the current body temperature becomes higher than the threshold temperature T1 within 10 seconds (second time t2) after it becomes lower than the threshold temperature T1 (step S13: No), the judgment unit 222 judges that there is no leakage and continues to compare the current body temperature based on the body temperature information at the current time t10 for each body temperature information input from each temperature sensor 32 with the threshold temperature T1 corresponding to that body temperature information (return to step S12).

In addition, leakage does not only occur when the injection fluid gradually leaks out of the blood vessel Bv, but also when a large amount of injection fluid leaks out of the blood vessel Bv in a short time, such as when the injection needle 113 penetrates the blood vessel Bv. At this time, the body temperature drops significantly in a short time in a part around the puncture site (for example, the first area Ar1). In such a case, it is necessary to make a judgment (leakage detection) earlier than waiting for the second time t2 to elapse after the body temperature drops to a predetermined temperature (threshold temperature T1) as in the first mode M1. In the second mode M2, in addition to detecting leakage using the first algorithm A1 similar to the first mode M1, leakage detection using the fourth algorithm A4 is performed in parallel, so that in addition to detecting leakage where the injection fluid gradually leaks out of the blood vessel Bv, leakage where a large amount of injection fluid leaks out of the blood vessel Bv can be detected in a shorter time.

Specifically, as shown in FIG. 11, the judgment unit 222 performs leakage detection (steps S11 to S14) using a first algorithm A1 that is the same as the first mode M1.

In parallel with this leakage detection, the judgment unit 222 compares the body temperature based on the body temperature information at a time 10 seconds before the current time t10 (third reference time t13) with the current body temperature for each body temperature information input from each temperature sensor 32. Then, when the body temperature based on the body temperature information at the current time t10 input from one temperature sensor 32 (e.g., the first temperature sensor 32a) is lower than the body temperature at a time 10 seconds before the current time t10 by 0.6°C (first temperature) or more (step S21: Yes) and by less than 6°C (second temperature) (step S22: No) (see FIG. 8), the judgment unit 222 judges that leakage has occurred (step S14).

Here, for any body temperature information input from any temperature sensor 32, if the current body temperature based on the body temperature information at the current time t10 has dropped by less than 0.6°C (first temperature) from the body temperature at the time 10 seconds before the current time t10 (step S21: No), the comparison of the body temperature based on the body temperature information at the time 10 seconds before the current time t10 (third reference time t13) with the current body temperature continues for each body temperature information input from each temperature sensor 32.

On the other hand, when the body temperature information input from one temperature sensor 32 (for example, the first temperature sensor 32a) shows that the current body temperature based on the body temperature information at the current time t10 has dropped by 6°C (second temperature) or more from the body temperature at a time 10 seconds before the current time t10 (third reference time t13) (step S21: Yes, step S22: Yes), the temperature drop is too large, and it is highly likely that the first temperature sensor 32a has detected the outside air (ambient temperature) due to peeling of the sheet 31a of the temperature detection unit 3 from the periphery of the puncture area, etc., and as a result, the judgment unit 222 judges that a detection error has occurred (step S23) and outputs an error signal to the alarm unit 23. Then, when the error signal is input, the alarm unit 23 outputs an error sound (a sound different from the alarm sound) from the speaker.

In addition, in the case of leakage, the range of the injection fluid leaked from the blood vessel Bv subcutaneously gradually expands over time as the leakage continues. Therefore, after the temperature of a part of the area Ar1 on the body surface (around the puncture site) is lowered by the injection fluid leaked from the blood vessel Bv, the area of the part (area) where the temperature is lowered on the body surface gradually expands to the area Ar2 surrounding the area Ar1 where the temperature was initially lowered (see symbols Ar1 and Ar2 in FIG. 1). The third mode M3 uses the second algorithm A2 to accurately detect the occurrence of leakage based on the expansion of the area where the body temperature is lowered due to the leakage. In the third mode M3 of this embodiment, the second time t2 is longer than in the first mode M1 to lower the sensitivity of leakage detection, and then the spread of the leaked injection fluid (range of body temperature decrease) is detected, thereby improving the accuracy (precision) of leakage detection compared to the first mode M1.

Specifically, as shown in FIG. 12, the reference temperature derivation unit 221 derives a reference temperature T for each piece of body temperature information from each temperature sensor 32 stored in the memory unit 223 (step S31).

Once the reference temperature T is derived for each piece of body temperature information, the judgment unit 222 compares the current body temperature based on the body temperature information at the current time t10 with the threshold temperature T1 corresponding to the body temperature information for each piece of body temperature information input from each temperature sensor 32 (step S32).

Then, when the current body temperature based on the body temperature information input from the temperature sensor 32 (e.g., the first temperature sensor 32a: see FIG. 1) at a position corresponding to the area (first area) Ar1 where the temperature first dropped around the puncture site is lower than the threshold temperature T1a corresponding to the body temperature information input from the first temperature sensor 32a for 30 consecutive seconds (second time t2) (step S33: Yes), and the current body temperature based on the body temperature information at the current time t10 is lower than the threshold temperature T1b corresponding to the body temperature information input from the second temperature sensor 32b based on the temperature information input from the second temperature sensor 32b located adjacent to the first temperature sensor 32a and adjacent to the first area Ar1 around the puncture site (step S34: Yes), the judgment unit 222 judges that leakage has occurred (step S35).

Here, in step S33, if the current body temperature becomes higher than the threshold temperature T1 within 30 seconds (second time t2) after it becomes lower than the threshold temperature T1 (step S33: No), the judgment unit 222 judges that there is no leakage and continues to compare the current body temperature based on the body temperature information at the current time t10 for each body temperature information input from each temperature sensor 32 with the threshold temperature T1 corresponding to that body temperature information (return to step S32).

In addition, in step S34, when the second time t2 has elapsed, based on the temperature information input from the second temperature sensor 32b, if the current body temperature based on the body temperature information at the current time t10 is higher than the threshold temperature T1b corresponding to the body temperature information input from the second temperature sensor 32b (step S34: No), the judgment unit 222 also judges that there is no leakage and continues to compare the current body temperature based on the body temperature information at the current time t10 for each body temperature information input from each temperature sensor 32 with the threshold temperature T1 corresponding to that body temperature information (return to step S32).

Furthermore, the fourth mode M4 detects leakage using the fifth algorithm A5 in parallel with the detection of leakage using the second algorithm A2 similar to the third mode M3, thereby detecting leakage where injection fluid gradually leaks out of the blood vessel Bv, and also detecting leakage where injection fluid leaks out of the blood vessel Bv in a shorter time. In the fourth mode M4 of this embodiment, a detection error is detected when the number of pieces of body temperature information where the current body temperature has dropped by the second temperature T12 or more from the body temperature based on the body temperature information at the third reference time t13 is two or more, so that it is possible to more accurately determine whether a detected large temperature drop is a detection error or not than in the second mode M2.

Specifically, as shown in FIG. 13, the judgment unit 222 performs leakage detection (steps S31 to S35) using the second algorithm A2, which is the same as the third mode M3.

In parallel with this leakage detection, the judgment unit 222 compares the body temperature based on the body temperature information at a time 10 seconds before the current time t10 (third reference time t13) with the current body temperature for each body temperature information input from each temperature sensor 32. Then, when the body temperature based on the body temperature information at the current time t10 in the body temperature information input from one temperature sensor 32 (e.g., the first temperature sensor 32a) is lower than the body temperature at a time 10 seconds before the current time t10 by 0.6°C (first temperature) or more (step S21: Yes) and by less than 6°C (second temperature) (step S22: No) (see FIG. 8), the judgment unit 222 judges that leakage has occurred (step S35).

Here, for any body temperature information input from any temperature sensor 32, if the current body temperature based on the body temperature information at the current time t10 has dropped by less than 0.6°C (first temperature) from the body temperature at the time 10 seconds before the current time t10 (step S21: No), the comparison of the body temperature based on the body temperature information at the time 10 seconds before the current time t10 (third reference time t13) with the current body temperature continues for each body temperature information input from each temperature sensor 32.

On the other hand, when the body temperature information input from two or more (plurality) temperature sensors 32 indicates that the current body temperature based on the body temperature information at the current time t10 has dropped by 6°C (second temperature) or more from the body temperature at a time 10 seconds before the current time t10 (third reference time t13) (step S21: Yes, step S22: Yes), the temperature drop is too large, and it is highly likely that the first temperature sensor 32a has detected the outside air (ambient temperature) due to the sheet 31a of the temperature detection unit 3 peeling off from the periphery of the puncture area, etc. As a result, the judgment unit 222 judges that a detection error has occurred (step S23) and outputs an error signal to the alarm unit 23. When the error signal is input, the alarm unit 23 outputs an error sound (a sound different from the alarm sound) from the speaker.

In addition, in the fifth mode M5, the second time t2 is set to 60 seconds in order to improve the detection accuracy of leakage (a type of leakage in which the injection fluid gradually leaks out of the blood vessel Bv) more than in the third mode M3. That is, in the fifth mode M5, the presence or absence of leakage is determined using the third algorithm A3, and therefore, except for the second time t2 being 60 seconds, the determination of the presence or absence of leakage by the determination unit 222 follows the same flow as that of the third mode M3 shown in FIG. 12.

The sixth mode M6 also has a second time t2 of 60 seconds to improve the detection accuracy of leakage (a type of leakage in which the injection fluid gradually leaks out of the blood vessel Bv) more than the fourth mode M4. That is, in the sixth mode M6, leakage detection is performed using the fifth algorithm A5 in parallel with leakage detection using the third algorithm A3. Therefore, except for the second time t2 being 60 seconds, the determination of the presence or absence of leakage by the determination unit 222 follows the same flow as that of the fourth mode M4 shown in FIG. 13.

According to the above-described leakage detection device 1, even if the body temperature of a wide area of the body surface, including the area around the puncture site, changes due to changes in the surrounding temperature or stress, as in the case of detecting leakage using the first algorithm A1, the average body temperature (reference temperature T) for the first time t1, which is set based on the current time t10, is used. In other words, by making a judgment about leakage based on the threshold temperature T1, which is based on the reference temperature T that changes in conjunction with the wide-area body temperature change on the body surface, the influence of the change in body temperature over the wide area of the body surface on the judgment of the presence or absence of leakage (leakage of injection fluid) is suitably suppressed, and leakage can be detected with high accuracy.

In more detail, when the value used to compare the body temperature (body surface temperature) around the puncture site to determine whether or not there is leakage is constant, it may be erroneously determined that there is leakage when the body temperature of the patient or the like drops over a wide area of the body surface, including the area around the puncture site, due to a drop in the ambient temperature (ambient temperature) such as room temperature or stress, etc. However, as in the leakage detection device 1 of this embodiment, by determining leakage using a value (threshold temperature T1 based on reference temperature T) that varies in response to fluctuations in body temperature over a wide area of the body surface, it is possible to prevent erroneous detection of leakage due to fluctuations in body temperature over a wide area of the body surface, and as a result, the accuracy of leakage detection is improved.

If leakage has already occurred at the current time t10, the body temperature around the puncture site has also begun to drop due to the leakage. Therefore, in the leakage detection device 1 of this embodiment, the second reference time t12 is set before the current time t10, and the threshold temperature T1 (reference temperature T) that serves as the criterion for determining leakage is derived excluding the body temperature at the current time t10 (i.e., the average body temperature between the first reference time t11 and the second reference time t12 is calculated). This makes it possible to avoid the influence of the drop in body temperature caused by leakage that has already occurred at the current time t10 when determining whether or not leakage has occurred, and thereby makes it possible to detect leakage more accurately.

In addition, in the leakage detection device 1 of this embodiment, for example, when detecting leakage using the fourth algorithm A4, the judgment unit 222 judges that leakage has occurred when the current body temperature has dropped by more than the first temperature T11 compared to the body temperature based on the body temperature information at the third reference time t13, which is before the current time t10 and after the second reference time t12, and the first temperature T11 is greater than the difference between the reference temperature T and the threshold temperature T1.

When the amount of leakage per unit time is large, the body temperature of some areas around the puncture site drops significantly in a short period of time. For this reason, as in the above configuration, by determining that leakage has occurred when a large drop in body temperature (greater than or equal to the first temperature T11) is detected in the short period of time between the third reference time t13 and the current time t10, it becomes possible to detect leakage with a large amount of leakage per unit time early (i.e., without passing the second time t2).

In addition, in the leakage detection device 1 of this embodiment, for example, when detecting leakage using the fourth algorithm A4, the judgment unit 222 judges that a detection error has occurred when the current body temperature drops by or exceeds a second temperature T12 that is greater than the first temperature T11 from the body temperature based on the body temperature information at the third reference time t13.

When using the leakage detection device 1, if the temperature sensor 32 detects an ambient temperature such as room temperature due to a part of the sheet 31a peeling off from the body surface (around the puncture site), the ambient temperature is sufficiently lower than body temperature, so the detected temperature drops more than the drop in body surface temperature caused by leakage. For this reason, as in the above configuration, a detection error is determined when the detected temperature (temperature based on body temperature information) drops below a threshold value of the second temperature T12, which is higher than the first temperature T11, in a short period of time, and it is possible to detect that a sensor or the like is not properly detecting body temperature around the puncture site. This allows proper detection of leakage around the puncture site by reattaching the sheet 31a, etc.

The leakage detection device 1 of this embodiment also has a temperature sensor (thermal element) 32 capable of detecting body temperature and outputting body temperature information (a signal corresponding to body temperature), and is equipped with a temperature detection unit 3 that removably fixes the temperature sensor 32 around the puncture site, and the temperature sensor 32 is directly or indirectly connected to the input unit 21 of the device main body 2. This allows the temperature sensor 32 that detects body temperature to be easily fixed around the puncture site and removed.

In addition, in the leakage detection device 1 of this embodiment, the temperature detection unit 3 has multiple temperature sensors 32 and a sheet (holding unit) 31a that holds the multiple temperature sensors 32 and can be attached around the puncture area, and the judgment unit 222 makes a judgment about leakage for each body temperature information from the temperature sensor 32.

When leakage occurs, the location (area) where a drop in body temperature (a drop in body temperature due to leakage) occurs around the puncture site is not constant. However, as in the above configuration, leakage can be detected over a wide range by determining leakage for each body temperature (body temperature information) detected at multiple locations around the puncture site, so leakage can be detected more reliably. Moreover, since multiple temperature sensors 32 are held on sheet 31a, multiple temperature sensors 32 can be appropriately positioned simply by attaching sheet 31a around the puncture site.

In addition, in the leakage detection device 1 of this embodiment, when the body temperatures detected by the majority (80% or more in this embodiment) of the plurality of temperature sensors 32 drop by the third temperature or more during the common third time period, the reference temperature derivation unit 221 erases the reference temperatures T corresponding to the previous plurality of temperature sensors 32 and obtains the reference temperatures T from the body temperature information corresponding to the subsequent plurality of temperature sensors 32. In this way, when the body temperatures detected by the majority of the plurality of temperature sensors 32 drop significantly (by the third temperature or more) simultaneously during a predetermined time period (common third time period), the reference temperatures T corresponding to the plurality of temperature sensors 32 are re-derived (i.e., reset), thereby suppressing the effect of an overall drop in body temperature due to a drop in ambient temperature, etc., on leakage detection, and thereby improving the accuracy of leakage detection. In other words, injection fluid leaking from the blood vessel Bv does not cause a simultaneous drop in body temperature (more specifically, a drop in the temperature of the body surface) over a wide area of the body surface (around the puncture site), so by determining that such a case is a drop in body temperature throughout the body due to the influence of room temperature, etc., and resetting (re-deriving) the reference temperature T, the effect of a drop in body temperature throughout the body on the detection of leakage can be suitably suppressed.

The leakage detection device of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, part of the configuration of one embodiment can be deleted.

In the above embodiment of the leakage detection device 1, the judgment unit 222 has five leakage detection algorithms A1 to A5, but is not limited to this configuration. The leakage detection device 1 may have one to four leakage detection algorithms, or six or more leakage detection algorithms. Furthermore, the combination of leakage detection algorithms may be a combination other than the combinations in the second mode M2, the fourth mode M4, and the sixth mode M6. Furthermore, the number of leakage detection algorithms to be combined may be three or more.

In addition, in the above embodiment of the leakage detection device 1, the length of the second time t2 is fixed for each leakage detection mode M1 to M6 and each leakage detection algorithm A1 to A5. In other words, the length of the second time t2 is changed by switching the leakage detection mode M1 to M6, but this configuration is not limited. The leakage detection device 1 may be capable of changing the length of the second time t2.

For example, the leakage detection device 1 may be configured such that only the second time t2 is changeable while the leakage detection algorithm used by the judgment unit 222 is fixed to one of the first to third algorithms A1 to A3.

When detecting leakage, there is a trade-off between the accuracy of leakage detection and the shortness of the time from when leakage occurs to when it is detected, but the above configuration makes it possible to adjust the balance between the accuracy of leakage detection and the early detection of leakage (the length of time from when leakage occurs to when it is detected). The details are as follows.

When detecting leakage, by lengthening the second time t2, the detection accuracy of leakage is improved, but the time from the occurrence of leakage to its detection is lengthened. In contrast, by shortening the second time t2, the time from the occurrence of leakage to its detection can be shortened, but the detection accuracy of leakage is reduced. For this reason, by making the length of the second time t2 variable as in the above configuration, the leakage detection device 1 can be adapted to both cases where the emphasis is on the detection accuracy of leakage and cases where the emphasis is on early detection of leakage.

In addition, in the leakage detection device 1 of the above embodiment, the calculation unit 22 that performs the process of determining whether or not there is leakage, the alarm unit 23, and the display unit 25 are arranged in the device body 2, but this configuration is not limited to this. For example, the display unit 25 may be configured as a separate unit from the device body 2, and a signal from the device body 2 may be input via a wired or wireless connection.

The leakage detection device 1 may have at least an alarm unit 23 as a configuration for outputting information regarding leakage, such as the presence or absence of leakage and the temperature of the body surface, to the outside. In other words, the leakage detection device 1 may not have a display unit 25.

The display unit 25 is not limited to a configuration that displays body temperature, temperature difference, etc., with shades of color, but may be configured to display different colors depending on body temperature or temperature difference. The display unit 25 may also have a portion other than the grid 251 that displays numbers, letters, etc. related to body temperature or leakage.

In addition, although the leakage detection device 1 of the above embodiment includes a temperature detection unit 3, this is not limited to this configuration. The leakage detection device 1 may not include a dedicated temperature detection unit 3, but may instead include a heat-sensing element (such as a temperature sensor) included in another device, and the signal from the heat-sensing element may be attached around the puncture site for purposes other than leakage detection, and may be input to the input unit 21.

In addition, in the temperature detection unit 3 of the leakage detection device 1 of the above embodiment, the multiple temperature sensors 32 are arranged in a grid pattern, but this configuration is not limited to this. In the temperature detection unit 3, the multiple temperature sensors 32 may be arranged in multiple concentric circles with different diameters, or in a radial arrangement. In other words, the multiple temperature sensors 32 only need to be arranged with a gap between each adjacent temperature sensor 32 within a specified area (range) of the sheet 31a.

In addition, in the temperature detection unit 3 of the leakage detection device 1 of the above embodiment, the multiple temperature sensors 32 are arranged on one sheet 31a, but this configuration is not limited to this. Each of the multiple temperature sensors 32 may be attached to the periphery of the puncture area in an independent state (for example, a configuration in which one temperature sensor 32 is arranged on one sheet 31a).

In addition, in the above embodiment of the leakage detection device 1, the temperature detection unit 3 has, for example, 25 temperature sensors, but is not limited to this configuration. The temperature detection unit 3 may have 24 or less or 26 or more temperature sensors 32.

In addition, in the temperature detection unit 3 of the leakage detection device 1 of the above embodiment, the sensor arrangement portion 311 of the sheet 31a is rectangular, and multiple temperature sensors 32 are arranged so as to spread over almost the entire area of the sensor arrangement portion 311, but this configuration is not limited to this. For example, as shown in FIG. 14, the sensor arrangement portion 311 may have a notch 3110, and the temperature detection unit 3 (more specifically, the sheet 31a) may be attached to the periphery of the puncture portion so that the inserted syringe 112 is located within the notch 3110. Also, as shown in FIG. 15, an extension portion 3111 where the temperature sensor 32 is not arranged may be provided at the end of the sensor arrangement portion 311 opposite the connector 33, and the extension portion 3111 may be attached to the body surface so as to overlap the syringe 112, thereby fixing the syringe 112 to the body surface.

In addition, in the above embodiment of the leakage detection device 1, the device body 2 and the temperature detection unit 3 are connected by a cable 4, but this configuration is not limited to this. The device body 2 and the temperature detection unit 3 may be directly connected. Furthermore, the device body 2 and the temperature detection unit 3 are not limited to being connected by a wire such as a cable 4, and may be connected wirelessly.

1...Leakage detection device, 2...Device body, 21...Input section, 22...Calculation section, 221...Reference temperature derivation section, 222...Judgment section, 223...Memory section, 23...Alarm section, 24...Operation section, 25...Display section, 251...Grid, 3...Temperature detection section, 31...Sheet section, 31a...Sheet (holding section), 311...Sensor arrangement section, 311a...Protective film, 311b...Temperature sensor film, 311c...Adhesive sheet, 311d...Release sheet, 312...Guideline, 32...Temperature sensor (thermal sensor), 32a...First temperature sensor, 32b...Second temperature sensor, 32c...Central temperature sensor, 33...Connector, 4...Cable, 100...Infusion device, 110...Infusion set, 111 ...Patient line, 112...syringe, 113...needle, 113a...tip, 115...tape, A1...first algorithm, A2...second algorithm, A3...third algorithm, A4...fourth algorithm, A5...fifth algorithm, Ar1...first region, Ar2...second region, Bv...blood vessel, M1...first mode, M2...second mode, M3...third mode, M4...fourth mode, M5...fifth mode, M6...sixth mode, T...reference temperature, T1, T1a, T1b...threshold temperature, T11...first temperature, T12...second temperature, t1...first time, t2...second time, t10...current time, t11...first reference time, t12...second reference time, t13...third reference time

Claims (8)

A leakage detection device for detecting leakage of an injection liquid injected into a blood vessel outside the blood vessel,
a device body capable of detecting the leakage based on the body temperature around a puncture part of a syringe needle for injecting the injection solution;
The device body includes:
an input unit to which body temperature information, which is a signal corresponding to the body temperature, is input;
a storage unit capable of storing the body temperature information input to the input unit;
a reference temperature derivation unit that derives a reference temperature over time, which is an average body temperature from a first reference time a certain time before the current time to a second reference time that is a first hour after the first reference time and before the current time, based on the body temperature information stored in the storage unit;
The leakage detection device has a judgment unit that judges that the leakage has occurred when the current body temperature based on the body temperature information at the current time is lower than a threshold temperature that is set lower than the reference temperature based on the reference temperature for a second consecutive hour, which is a time that is shorter than the first hour. The leakage detection device according to claim 1, wherein the second reference time is earlier than the current time. The leakage detection device according to claim 1 or 2, wherein the device body is capable of changing the length of the second time. The determination unit also determines that the leakage has occurred when the current body temperature is lower than a body temperature based on the body temperature information at a third reference time that is before the current time and after the second reference time by a first temperature or more,
The leakage detection device of claim 2 , wherein the first temperature is greater than a difference between the reference temperature and the threshold temperature. The leakage detection device according to claim 4, wherein the judgment unit judges that a detection error has occurred when the current body temperature has dropped by a second temperature greater than the first temperature from the body temperature based on the body temperature information at the third reference time. a temperature detection unit having a heat-sensing element capable of detecting the body temperature and outputting the body temperature information, and removably fixing the heat-sensing element to the periphery of the puncture part;
6. The leakage detection device according to claim 1, wherein the heat sensitive element is connected to the input section of the device body. the temperature detection unit has a plurality of the heat-sensitive elements and a sheet-like holder that holds the plurality of heat-sensitive elements and can be attached to the periphery of the puncture portion;
The leakage detection device according to claim 6 , wherein the determination unit determines whether or not leakage has occurred for each of the body temperature information from the heat sensitive element. The leakage detection device according to claim 7, wherein when the body temperatures detected by a majority of the plurality of heat-sensitive elements drop by a third temperature or more during a common third time period, the reference temperature derivation unit erases the reference temperatures corresponding to the plurality of heat-sensitive elements prior to that time and determines the reference temperatures from the body temperature information corresponding to the plurality of heat-sensitive elements thereafter.

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