Weighing apparatus

Abstract

To provide a weighing apparatus capable of detecting needle detachment in dialysis treatment.SOLUTION: A weighing apparatus 1 comprises: a weighing part 10 with a load sensor 12 for outputting a weighing signal according to a load applied to a measuring table 4; and a control arithmetic part 20 for calculating a weighing value from the weighing signal. The weighing apparatus 1 is placed on the measuring table 4, and monitors a weight of a patient undergoing dialysis treatment. The control arithmetic part 20 calculates a weighing value W successively at a predetermined interval, calculates a change in the weighing value per unit hour during the patient's dialysis treatment as a weighing value change ΔW / ΔT, and in comparison between the weighing value change ΔW / ΔT and a set water removing speed R, determines whether or not needle detachment of a dialysis needle is present, and provides a notification of the needle detachment.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to weighing devices, and more particularly to weighing devices that weigh a patient over an extended period of time. [Background technology]

[0002] Conventionally, as weighing devices used in hemodialysis treatment, bed-type weighing scales (scale beds) and chair-type weighing scales (reclining scales) are known. The scale bed disclosed in Patent Document 1 is provided with load sensors on the legs, and is capable of measuring the weight of a patient on the bed for a long period of time.

[0003] In hemodialysis treatment, a dialysis needle attached to the end of a tube in a dialysis machine is inserted into a patient's blood vessel, the blood vessel is connected to the dialysis machine with a tube, the blood is taken out of the body, ultrafiltered and solutes are removed, and the blood is returned to the body. The dialysis needle is fixed to the patient with adhesive tape, etc., but needle removal (also known as needle removal accidents) can occur due to insufficient fixation, changes in position such as turning over in bed, or the patient removing the needle or blood circuit themselves.

[0004] For this reason, various means for monitoring needle dislodgement have been proposed. For example, Patent Document 2 discloses a needle dislodgement detection device that includes an ultrasonic probe and a judgment unit. The ultrasonic probe transmits ultrasonic waves to a dialysis needle inserted into a blood vessel and receives ultrasonic waves reflected by the dialysis needle. The judgment unit analyzes the needle signal strength output by the ultrasonic probe to judge the state of the puncture needle in the blood vessel. In addition, some dialysis devices equipped with pumps themselves are equipped with safety means for stopping the operation of the pump when the internal pressure of the blood circuit falls below a threshold value. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-020805 A [Patent Document 2] JP 2015-100546 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, various proposals have been made to detect needle dislodgement, but not all dialysis systems are equipped with perfect monitoring means. Even if a monitoring means is equipped, it may not function reliably. Needle dislodgement causes heavy bleeding in a short period of time, and can lead to serious, life-threatening accidents, which occur quite frequently. For this reason, there has been a demand for the development of a device that can detect needle dislodgement using a different method than conventional methods, that is, a weighing device that measures weight change, as a means of double and triple checking.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide a measuring device that can detect needle dislodgement during dialysis treatment. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention has the following configuration. 1. A weighing device comprising a weighing unit having a load sensor which outputs a weighing signal according to the load applied to the measuring platform, and a control and calculation unit which calculates a weighing value from the weighing signal, and which monitors the weight of a patient placed on the measuring platform undergoing dialysis treatment, wherein the control and calculation unit sequentially calculates the weighing value at predetermined intervals, calculates the change in the weighing value per unit time during the patient's dialysis treatment as the weighing value change, compares the weighing value change with a set water removal speed to determine whether or not the dialysis needle has come out, and notifies the patient of the needle coming out.

[0009] 2. In the above aspect 1, it is also preferable to determine that the measurement value change is normal when it is a value corresponding to the set water removal speed, and to determine that the needle has come out when the measurement value change is not a value corresponding to the set water removal speed.

[0010] 3. In the above aspects 1 and 2, it is also preferable to determine that the needle has come out of the venous side of the dialysis machine when the change in the measurement value is a value corresponding to a negative value of the blood flow rate set for the dialysis machine used for the dialysis treatment.

[0011] 4. In the above aspects 1 to 3, it is also preferable to determine that the needle has dislodged from the arterial side of the dialysis device when the change in the measurement value is a value corresponding to the difference between the blood flow rate set for the dialysis device used in the dialysis treatment and the set water removal rate.

[0012] 5. In the above aspects 1 to 4, it is also preferable that the device further comprises a display for displaying the measurement value and the change in the measurement value, and the control and calculation unit updates the display of the measurement value and the change in the measurement value each time the measurement value is calculated.

[0013] 6. In the above-mentioned aspect 5, it is also preferable that the needle dislodgement is notified by displaying it on the display. Effect of the Invention

[0014] According to the above aspect, it is possible to detect needle dislodgement during dialysis treatment using the measuring device. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing a configuration of a weighing device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a block diagram of the weighing device. [Diagram 3] FIG. 2 is a diagram illustrating the state in which the measuring device is used during dialysis treatment. [Figure 4] FIG. 13 is a diagram for explaining the state of use of the measuring device in dialysis treatment, and is a diagram for explaining the state in which the needle has come out on the venous side. [Diagram 5] 13 is a flowchart showing a process for detecting needle loss using the weighing device. [Figure 6] 13(A) and (B) are diagrams showing an example of the display of the weighing device. [Figure 7] 13 is a flowchart of needle removal detection using a weighing device according to one modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. Note that the dimensions of each part in the drawings are appropriately enlarged or reduced for the convenience of explanation, and the scale is not necessarily accurate.

[0017] 1. Weighing device 1 is a schematic side view of a weighing device 1 according to an embodiment. In this embodiment, the weighing device 1 is a scale bed capable of measuring the weight of a patient P lying thereon. The weighing device 1 is used together with a dialysis machine 9. The weighing device 1 measures the weight of the patient P during dialysis and detects whether the needle has come out based on the rate of change in weight.

[0018] As shown in FIG. 1, the weighing device 1 is configured as a bed 2 in appearance.

[0019] The bed 2 comprises a mattress 3 on which a patient can lie, a frame 4 that holds the mattress 3, and four legs 5 that support the frame 4. A headboard 6 is attached to the head end of the frame 4, and a footboard 7 is attached to the foot end. The frame 4 with the mattress 3 attached thereto corresponds to the measuring table in the claims.

[0020] A load sensor 12 is provided on each of the four legs 5. A display device 30 is attached to the upper part of the footboard 7. The display device 30 is configured with a thick plate-shaped housing, and has a display 31 and an input interface 32 on its surface (see also FIG. 3).

[0021] 2 is a configuration block diagram of the weighing device 1. The weighing device 1 includes a weighing unit 10, a control and calculation unit 20, a display 31, an input interface 32, and a storage unit 40.

[0022] The weighing unit 10 includes the above-mentioned load sensor 12, which may be, for example, a strain gauge type, capacitance type, spring type, or other load cell. The load sensor 12 is connected to the control and calculation unit 20 via an A / D converter (not shown), and is configured to output a weighing signal corresponding to the load applied to the mattress 3 to the control and calculation unit 20.

[0023] The control and calculation unit 20 includes at least one electronic circuit 21 and at least one memory 22. For example, a processor such as a CPU (Central Processing Unit) is used as the electronic circuit 21. For example, a static random access memory (SRAM) or a dynamic random access memory (DRAM) is used as the memory. When a CPU is used, the control and calculation unit 20 executes the functions of the weighing device 1 by reading a program for the CPU to execute the functions into the memory and executing the program.

[0024] Specifically, the control and calculation unit 20 calculates a measurement value in response to a measurement signal input from the load sensor 12. The control and calculation unit 20 also calculates a blood flow rate Q B , the average water removal rate (hereinafter simply referred to as the water removal rate) R, and the target weight W T etc. Furthermore, the weighing value is calculated sequentially at a predetermined interval, and the weighing value change per unit time ΔW / ΔT (i.e., the rate of change in the weighing value) is calculated over time. That is, the time ΔT is the calculation period of the weighing device 1. Furthermore, the weighing value change ΔW / ΔT is compared with the set water removal speed R to determine whether the dialysis needle has come out. The set water removal speed R is also the water removal speed R set in the dialysis device 9 used simultaneously with the weighing device 1. Furthermore, the control calculation unit 20 issues an alarm if needle dislodgement is detected.

[0025] At least a part of the control calculation unit 20 may be configured as hardware using a CPLD (Complex Programmable Logic Device), an FPGA (Field Programmable Gate Array), or the like. When a CPLD or an FPGA is used, a circuit configured on an element realizes the function. That is, the control calculation unit 20 may include a processor that realizes the function using software and a processing circuit that realizes the function using hardware.

[0026] The display 31 is, for example, a liquid crystal display, an organic EL display, or the like, and displays the weight measured by the weighing unit 10, i.e., the patient's weight, and various information related to dialysis treatment. T , water removal rate R, blood flow rate Q B , weight change since the start of treatment, and other information, including a display to notify the patient that dialysis is in progress and an alarm to detect needle dislodgement.

[0027] The input interface 32 is, for example, a key switch, and includes a power button, a mute button, a start / stop button, a setting change button, etc. Measurement start / stop instructions and user settings and selections can be input via the input interface 32. The input interface 32 may be integrated with the display 31 as a touch panel display.

[0028] The storage unit 40 is, for example, a HDD, a flash memory, etc. The storage unit 40 stores programs and the like for the control and calculation unit 20 to execute the functions of the weighing device 1.

[0029] 2. Dialysis machine Here, the dialysis machine 9 used simultaneously with the measuring device 1 will be described. FIG. 3 is a diagram showing the measuring device 1 in use. In the dialysis room, the dialysis machine 9 is placed adjacent to the bed 2 on which the patient P is positioned. The dialysis machine 9 is generally comprised of a dialyzer 91 that removes waste products and excess water from the blood using a dialysis membrane, an arterial tube 92 that connects the dialyzer 91 to the artery of the patient P or a vein in which a shunt has been formed, a venous tube 93 that connects the patient's vein to the dialyzer 91, and a blood flow rate Q B The blood pump 94 pumps the liquid in the arterial tube 92, and the dialysate supply and discharge device 96 supplies the dialysate contained in the dialysate container 95 to the dialyzer 91 and discharges it from the dialyzer 91.

[0030] Dialysis needles 92a, 93a are attached to the tips of the arterial tube 92 and the venous tube 93. The dialysis device 9 also includes a control unit 97 that controls the blood pump 94, an input unit 98 electrically connected to the control unit 97 for inputting operation signals to the control unit 97, and a display unit 99 electrically connected to the control unit 97 for externally displaying output signals from the control unit 97.

[0031] During dialysis treatment, first, the dialysis needles 92a, 93a are inserted into the blood vessels of the patient P and fixed with a fixing tape or the like. Next, by driving the blood pump 94, blood is taken out of the patient P's body from the arterial tube 92 at a set blood flow rate, and is made to permeate the dialysis membrane of the dialyzer 91 to remove dialysis waste products and water, and the blood is returned to the patient's body from the venous tube 93.

[0032] 3. Needle dropout detection method Next, a needle dropout detection method using the weighing device 1 will be described. In general, prior to dialysis treatment, the dry weight DW is determined and the pre-treatment weight W0 is measured. Based on these, the water removal rate R and treatment time T D , blood flow Q B etc. shall be determined.

[0033] Dry weight (DW) is the weight at the time when the extracellular fluid volume is corrected by dialysis treatment, i.e., the target weight after treatment (W T First, the dry weight (DW) is determined by a doctor based on a comprehensive assessment of the patient's physical condition using X-rays, etc.

[0034] Next, the pre-treatment weight W0 and the target weight W T The difference between the maximum water removal rate MR and the maximum water removal rate DW is calculated. This difference is equal to the maximum water removal rate MR by dialysis treatment. Next, the water removal rate R is determined. The guidelines of the Japanese Society for Dialysis Therapy recommend that the water removal rate R be 15 mL / kg / hour or less relative to the dry weight DW. That is, for example, when the dry weight DW is 60 kg, the water removal rate is recommended to be 900 mL / hour, i.e., 15 mL / min or less. The water removal rate R is determined according to this guideline. The water removal rate R is calculated by multiplying the maximum water removal rate MR by the treatment time T D Treatment time T D is determined to meet this requirement. Treatment time is generally around 4 hours.

[0035] Next, the blood flow rate Q is set to achieve this water removal rate R. B Determine the blood flow rate Q B is determined taking into consideration the balance of the shunt vessel, physique, age, patient condition, type of dialyzer, etc. B The flow rate is generally around 200 mL / min. Note that mass and volume, such as body weight, can be converted using the density of blood. For convenience, it is acceptable to convert using a density of 1 g / mL.

[0036] The treatment time T determined in this way D and blood flow rate Q B is set in the dialysis device 9, a dialysis needle is inserted into the patient to connect the blood circuit, and the dialysis device 9 is operated at the set blood flow rate Q B By this, the patient's weight is measured at any time during dialysis and the target weight W TDialysis is continued until the weight W (patient P's weight) decreases at a weight change ΔW / ΔT that is approximately equal to the water removal rate R. Here, the weight change ΔW / ΔT in the case of a decrease is a negative value, and the weight change ΔW / ΔT in the case of an increase is a positive value.

[0037] When the dialysis needle 93a of the venous tube 93 is removed from the puncture site, as shown in FIG. 4, blood stops flowing into the body from the venous tube 93, and blood flows out of the arterial tube 92 at a blood flow rate Q B In other words, if the tip of the venous tube 93 comes off from the dialysis bed, the change in the weight value ΔW / ΔT will differ from the water removal speed R.

[0038] On the other hand, when the dialysis needle 92a of the arterial tube 92 is removed from the punctured portion, blood does not flow out of the body, and a flow rate Q B Therefore, the weight change ΔW / ΔT does not decrease with the water removal rate R, and the blood flow rate Q B and the water removal rate R.

[0039] In this way, when the needle is in a normal state (i.e., when the needle does not slip out), the change in the weight value ΔW / ΔT corresponds to the negative value -R of the water removal speed R. On the other hand, when the needle slips out on the venous side, the change in the weight value ΔW / ΔT corresponds to the blood flow rate Q B Negative value of -Q B When the needle is removed from the artery, the change in the weight ΔW / ΔT is the blood flow rate Q B and the difference between the water removal rate Q and the water removal rate R B -R. The water removal rate R is 15 mL / min, and the blood flow rate Q B Considering that the water removal rate is about 200 mL / min, the difference in the weight change ΔW / ΔT between normal and needle dislodgement is significant. Therefore, it is possible to determine that needle dislodgement has occurred when the weight change ΔW / ΔT does not correspond to the water removal rate R.

[0040] 4. Operation during use 5 is a flowchart of the operation of the weighing device 1 during dialysis treatment. This operation is started by turning on the power of the weighing device 1 or starting the needle dropout monitoring mode. When the weighing device 1 starts its operation, the load sensor 12 constantly outputs a load signal to the control and calculation unit 20. The control and calculation unit 20 calculates the weighing values ​​W1, W2, W3,... at a predetermined interval (ΔT). Furthermore, the control and calculation unit 20 displays the weighing values ​​W1, W2, W3,... on the display 31 and updates the display each time it calculates them.

[0041] The dry weight DW is determined in advance. The body weight before treatment W0 is also measured. Based on these, the water removal rate R and treatment time T D , blood flow Q B etc. are determined in advance.

[0042] The dialysis machine 9 is provided with at least a blood flow rate Q B In addition, to monitor the progress of dialysis treatment, the pretreatment weight W0, the water removal rate R, and the target weight W T、 Treatment time T D etc. may be set.

[0043] When the weighing device 1 starts to operate, first, in step S01, the control and calculation unit 20 calculates the blood flow rate Q B For example, the control and calculation unit 20 displays the blood flow rate Q B In response to the display, the operator inputs the blood flow rate Q via the input interface 32. B By inputting the value of B The blood flow rate Q set in the measuring device 1 is B and the blood flow rate set in the dialysis machine 9 are the same value.

[0044] Next, in step S02, the control and calculation unit 20 sets the water removal speed R. For example, the control and calculation unit 20 displays a message on the display 31 prompting the operator to input the water removal speed R, and the operator sets the water removal speed R by inputting the value of the water removal speed R via the input interface 32 in response to the display.

[0045] Next, in step S03, the control calculation unit 20 calculates the target weight W T The setting is performed by setting a value input via the input interface 32, similarly to steps S01 and S02.

[0046] After step S03, when the dialysis machine 9 is driven, the control and calculation unit 20 starts needle dislodgement monitoring in step S04. Needle dislodgement monitoring is started, for example, by an operator issuing an instruction via the input interface 32.

[0047] Next, in step S05, the control calculation unit 20 calculates the weight value W n (n is a natural number) is calculated, and the display on the display 31 is updated. FIG. 6(A) shows an example of a display image on the display 31. As shown in FIG. 6(A), the display 31 displays the current weighing value W n (i.e., body weight) and the change in the weighing value (change in body weight) ΔW / ΔT calculated in the next step S06 is, for example, the target body weight W T , water removal rate R, blood flow rate Q B The display shows the set value and a message indicating that dialysis is in progress.

[0048] Next, in step S06, the control calculation unit 20 calculates the weight value change ΔW / ΔT. The weight value change ΔW / ΔT is calculated by the following formula 1. ΔW / ΔT=(W n -W n-1 ) / ΔT (Equation 1) (Where, n is the current measurement value, W n-1 is the previous measurement value, and ΔT is the calculation period.)

[0049] Next, in step S07, the control calculation unit 20 compares the measurement value change ΔW / ΔT with the set water removal speed R to determine whether the measurement value change ΔW / ΔT is a value corresponding to the negative value -R of the set water removal speed R. Here, whether the measurement value change ΔW / ΔT is a value corresponding to the negative value -R of the water removal speed R is determined based on a predetermined threshold value T RSet the weight change ΔW / ΔT to -R±T R This is done by judging whether the threshold T R Setting this as above is advantageous in that it makes it possible to ignore fluctuations in the weight values ​​due to the movement of the patient P, the vibration of the bed, disturbances, and the like.

[0050] In step S07, if the weight value change ΔW / ΔT is a value corresponding to the negative value -R of the set water removal speed R (YES), the control calculation unit 20 determines that it is normal (needle dislodgement has not occurred), and in step S08, waits for a time ΔT before calculating the weight value.

[0051] Next, in step S09, the control calculation unit 20 calculates the weight value W n+1 Then, in step S10, the weight value W n+1 But my target weight is W T Determine whether the weight value W is equal to or less than the following. n+1 But my target weight is W T If it is not equal to or less than n (NO), the process returns to step S06, n is incremented to n=n+1, and the process is repeated. n+1 But my target weight is W T If the following is true (YES), the process ends.

[0052] On the other hand, in step S07, if the weight change ΔW / ΔT is not a value corresponding to the negative value −R of the set water removal speed R (NO), in step S11, the control calculation unit 20 determines that needle dislodgement has occurred.

[0053] Then, in step S12, the control and calculation unit 20 notifies the user that the needle has fallen out, and ends the process. The notification may be performed, for example, by displaying a message on the display 31 to warn that the needle has fallen out, as shown in Fig. 6(B). Alternatively, the entire display 31 may be made to flash, so that the user can be aware of the abnormality from a distance.

[0054] Furthermore, instead of or in addition to the above-described notification by the display 31, the weighing device 1 may be provided with a speaker (not shown) and may issue an alarm or a voice notification when a needle has fallen out. These notification methods may also be combined.

[0055] In this way, the weighing device 1 is configured to calculate the change in weighing value ΔW / ΔT over time and compare it with the water removal rate R set in the dialysis device 9 used at the same time, thereby making it possible to detect needle dislodgement from the patient P during dialysis treatment by the dialysis device 9. This makes it possible to detect needle dislodgement by a method different from the conventional method. Since the detection of needle dislodgement by the weighing device 1 is performed independently of the dialysis device 9, it is useful as a means of double-checking and triple-checking even if the needle dislodgement monitoring means provided in the dialysis device 9 does not function properly.

[0056] The above-mentioned method for detecting needle dislodgement by the weighing device 1 is effective when the dialysis needles 92a, 93a are completely removed from the patient's blood vessels and blood flows out of the bed 2, but it is not possible to detect needle dislodgement when the dialysis needles 92a, 93a are not completely removed from the patient's blood vessels or when the needles remain inside the bed 2 even after they are completely removed. However, about half of the causes of needle dislodgement are self-removal, where the patient removes the needle themselves due to discomfort with the fixed dialysis needles 92a, 93a or dialysis circuit, and blood often flows out of the bed 2. In this case, it can be a serious accident that threatens the patient's life, so this new method for detecting needle dislodgement is effective.

[0057] In addition, if the blood pump 94 is equipped with an internal pressure sensor and a safety means for emergency stopping the pump when the internal pressure drops as a needle drop monitoring means of the dialysis device 9, the pump will be stopped in an emergency when the internal pressure sensor drops below a predetermined threshold. However, the response time of the load sensor 12, specifically, the measured value W nIf the measurement interval (i.e., time ΔT) is shorter than the response time of the internal pressure sensor of the dialysis device 9, the metering device 1 can detect needle dislodgement before the dialysis device 9 does.

[0058] In addition, the weighing device 1 monitors the needle dropout and also records the weighing value W n and the change in weight value ΔW / ΔT are displayed for each calculation. Normally, the dialysis machine 9 itself does not have the function of measuring the patient's weight. Therefore, during dialysis treatment, it is assumed that dialysis is proceeding at the theoretical water removal rate R, and the change in weight is measured after dialysis treatment to confirm that dialysis has been performed without any problems. The weighing device 1 displays the actual weight value W n Since the display is updated every time the change in the weight values ​​ΔW / ΔT is calculated, an operator such as a nurse can compare the display of the dialysis device 9 with the display of the measuring device 1 to visually confirm that dialysis is being performed at the set water removal speed R. Furthermore, in the unlikely event that there is a discrepancy between the set water removal speed R and the change in the weight values ​​ΔW / ΔT, it becomes possible to take prompt action to correct this.

[0059] 5. Variation 1 FIG. 7 is a flowchart of the operation of the weighing device 1a according to the first modification. The mechanical configuration of the weighing device 1a is the same as that of the weighing device 1. As described above, when the needle dislodges on the venous side, the weight change ΔW / ΔT is B Negative value of -Q B If the needle comes out from the artery, the blood flow rate Q B The value Q obtained by subtracting the water removal rate R from B For example, if the water removal rate R is 15 mL / min and the blood flow rate Q B If the flow rate is 200 mL / min, the change in the measured value ΔW / ΔT will be -15 mL / min under normal circumstances, but if the needle dislodges on the venous side, it will be -200 mL / min, and if the needle dislodges on the arterial side, it will be +185 mL / min.

[0060] In the weighing device 1a, based on this difference, a control calculation unit (not shown) adds the weight change ΔW / ΔT to the water removal speed R to obtain the blood flow rate Q BThis is then compared to determine whether the needle dislodgement occurred on the venous or arterial side.

[0061] When the process starts in the weighing device 1a, the same process as steps S01 to S10 is executed in steps S101 to S110. Then, when it is determined in step S107 that the weight value change ΔW / ΔT is not a value corresponding to the negative value -R of the set water removal speed R (NO), in step S111, the control calculation unit converts the weight value change ΔW / ΔT into the blood flow rate Q B By comparing this, it is possible to determine whether the needle dislodgement occurred on the venous or arterial side.

[0062] In step S111, the change in the measurement value ΔW / ΔT is calculated based on the blood flow rate Q B Negative value of -Q B If the value corresponds to, in step S112, the control and calculation unit determines that the needle dislodgment occurred on the vein side. Then, in step S113, the control and calculation unit notifies that the needle dislodgment occurred on the vein side, and ends the process.

[0063] In step S111, the change in the measurement value ΔW / ΔT is calculated based on the blood flow rate Q B and the difference between the water removal rate Q and the water removal rate R B If the value corresponds to -R, in step S114, the control and calculation unit determines that needle dislodgement has occurred on the arterial side. Then, in step S115, the control and calculation unit notifies that needle dislodgement has occurred on the arterial side, and ends the process.

[0064] The notification in steps S113 and S115 can be performed by using a method such as displaying a warning message on the display 31, emitting a warning sound through a speaker, or notifying by voice, as in step S12. In this case, it is preferable to notify in steps S113 and S115 in a manner that allows instant identification of whether it is the venous side or the arterial side, such as by flashing in a different color or making different warning sounds. In this way, the operator can easily search for the needle dislodged site.

[0065] In step S111, the change in the weight value ΔW / ΔT is calculated based on the blood flow rate QB Negative value of -Q B The value of the blood flow Q B and the difference between the water removal rate Q and the water removal rate R B If the value does not correspond to −R, the control calculation unit determines in step S116 that there is another abnormality. For example, the other abnormality is when the needle comes out from both the arterial side and the venous side, or when there is an abnormality in the water removal speed R itself. In this case, the process proceeds to step S117, where the control calculation unit issues a warning to that effect using a display device or a speaker (not shown), and ends the process.

[0066] In the determination of step S111, the blood flow rate Q B Negative value of -Q B The value corresponding to the blood flow rate Q B and the difference between the water removal rate Q and the water removal rate R B The determination of the value corresponding to −R is performed in the same manner as in step S07, using the blood flow rate Q B Negative value of -Q B , blood flow Q B and the difference between the water removal rate Q and the water removal rate R B Upper and lower thresholds are set for each of -R, and a judgment is made based on whether or not the value is within the range of the thresholds.

[0067] In this way, in the weighing device 1a according to the first modification, the change in the weighing value ΔW / ΔT is calculated based on the blood flow rate Q in addition to the water removal rate R. B In comparison with the conventional needle dislodgement technique, this technique is configured to determine whether the needle dislodgement occurred on the venous side or the arterial side, making it easier for the operator to identify the location of the needle dislodgement.

[0068] Although the preferred embodiment and modifications of the present invention have been described above, these can be modified and combined based on the knowledge of those skilled in the art, and such modifications are also within the scope of the present invention. In the above embodiment, the present invention has been described as being applied to a scale bed, but it goes without saying that the present invention is not limited to this, and can be applied to any weighing device that can measure changes in a patient's weight over an extended period of time, such as a stretcher scale or a reclining scale. [Explanation of symbols]

[0069] 1:Measuring device 9: Dialysis machine 10:Measuring part 12: Load sensor 20: Control calculation section 31: Display 92a: Dialysis needle (arterial side) 93a: Dialysis needle (venous side)

Claims

1. a weighing unit including a load sensor that outputs a weighing signal corresponding to a load applied to the measurement table; a control and calculation unit for calculating a weight value from the weight signal, A weighing device for monitoring the weight of a patient undergoing dialysis treatment placed on the measurement table, The control calculation unit is The measured value is calculated sequentially at a predetermined interval; Calculating a change in the metric value per unit time during the dialysis treatment of the patient as a metric value change; A measuring device characterized by comparing the change in the weighing value with a set water removal speed to determine whether or not the dialysis needle has come out, and notifying the user of the needle coming out.

2. When the change in the measured value corresponds to the set water removal speed, the change is determined to be normal; The weighing device according to claim 1, characterized in that it is determined that the needle has come out when the change in the weighing value is not a value corresponding to the set water removal speed.

3. The measuring device according to claim 2, characterized in that it is determined that the needle has come out of the venous side of the dialysis device when the change in the measured value is a value corresponding to a negative value of the blood flow rate set for the dialysis device used for the dialysis treatment.

4. The measuring device according to claim 2, characterized in that it is determined that the needle has come out of the arterial side of the dialysis device when the change in the measured value is a value corresponding to the difference between the blood flow rate set for the dialysis device used in the dialysis treatment and the set water removal rate.

5. a display for displaying the metric value and the metric value change; 3. The weighing device according to claim 1, wherein the control and calculation unit updates the display of the weight value and the change in the weight value every time the weight value is calculated.

6. 6. The weighing device according to claim 5, wherein the needle loss is notified by displaying the information on the display.

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