Drip monitoring device

Abstract

To provide an intravenous drip monitoring device capable of accurately measuring a drip interval.SOLUTION: A intravenous drip monitoring device 1 comprises: a signal change detection unit 82 that detects, as a signal change, a change in light received by a light receiving unit 6; a droplet recognition unit 83 that recognizes, as a droplet, a change in a signal detected by the signal change detection unit 82; a droplet processing unit 84 that sets a mask period during which the droplet recognition unit 83 does not recognize, as a droplet, a change in the signal detected by the signal change detection unit 82; and a drip interval measurement unit 85 that measures, as a drip interval, an interval between changes in the signal recognized as a droplet by the droplet recognition unit 83.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an infusion monitor. [Background technology]

[0002] Conventionally, drip monitoring devices are known that monitor droplets formed at the drip outlet of an infusion set used during infusion therapy. The drip monitoring device monitors the flow rate of the infusion, etc., and medical professionals such as doctors and nurses can take appropriate measures based on the monitoring results.

[0003] Such drip monitoring devices include a light-emitting unit and a light-receiving unit, and detect droplets in the drip tube by irradiating light from the light-emitting unit and detecting the light attenuated by the droplets with the light-receiving unit. The flow rate of the infusion is calculated from the interval between droplets. However, such drip monitoring devices can sometimes erroneously detect droplets if droplets bounce back or otherwise occur.

[0004] Therefore, in order to prevent erroneous detection due to droplets bouncing off, etc., an infusion monitor device has been proposed in which a light-emitting element and a light-receiving element are placed on the same side of the infusion tube, and the light output from the light-emitting element hits the droplets falling inside the infusion tube, and the scattered light is detected by the light-receiving element (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-125450 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when a droplet falls inside the drip tube and hits the liquid surface, the droplet may bounce off the liquid surface and reach the light-emitting and light-receiving units. The output of the light-receiving unit may decrease for both droplets falling from above and droplets bouncing off from below, potentially causing the drip monitor to recognize them as droplets. In this case, the drip monitor will falsely detect droplets and be unable to accurately measure the interval between droplets to calculate the infusion flow rate.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an infusion monitor that can accurately measure the interval between drops. [Means for solving the problem]

[0008] The present invention is an infusion monitoring device that monitors the dripping of droplets of infusion fluid within an infusion tube, and includes: a light-emitting unit that irradiates light onto the droplets; a light-receiving unit that receives the light irradiated from the light-emitting unit; a signal change detection unit that detects changes in the light received by the light-receiving unit as signal changes; a droplet recognition unit that recognizes the signal changes detected by the signal change detection unit as droplets; a droplet processing unit that sets a mask period during which the signal changes detected by the signal change detection unit are not recognized as droplets by the droplet recognition unit; and a droplet interval measurement unit that measures the interval between signal changes recognized as droplets by the droplet recognition unit as a droplet interval.

[0009] The droplet processing unit also sets a mask period during which the droplet recognition unit does not recognize the droplets, based on the droplet interval measured immediately before.

[0010] The drip monitoring device further includes a flow rate calculation unit that calculates the flow rate of the infusion based on the drip interval measured by the drip interval measurement unit.

[0011] The flow rate calculation unit calculates the flow rate of the infusion based on the droplet intervals of the droplets recognized by the droplet recognition unit within a certain period of time.

[0012] The drip monitoring device further includes a notification control unit that, when the droplet recognition unit recognizes the droplet, causes a light emitting device to emit light to notify the user that the droplet has been recognized.

[0013] Furthermore, the droplet processing unit does not set the mask period when the droplet interval is less than the processable period.

[0014] The present invention is an infusion monitoring device that monitors the dripping of droplets of infusion fluid within an infusion tube, and includes: a light-emitting unit that irradiates light onto the droplets; a light-receiving unit that receives the light irradiated from the light-emitting unit; a signal change detection unit that detects changes in the light received by the light-receiving unit as signal changes; a droplet recognition unit that recognizes the signal changes detected by the signal change detection unit as droplets; a droplet interval measurement unit that measures the interval between signal changes recognized as droplets by the droplet recognition unit as a droplet interval; and a droplet processing unit that, if the droplet interval is equal to or longer than a predetermined period, determines that the droplet interval is subject to calculation of the infusion flow rate, and, if the droplet interval is shorter than the predetermined period, determines that the signal change detected later, of the two signal changes used to measure the droplet interval, is not subject to measurement of the droplet interval by the droplet interval measurement unit.

[0015] The droplet processing unit also sets the predetermined period based on the droplet interval measured immediately before.

[0016] The drip monitoring device further includes a flow rate calculation unit that calculates the flow rate of the infusion based on the droplet interval determined by the droplet processing unit to be subject to flow rate calculation.

[0017] The flow rate calculation unit calculates the flow rate of the infusion based on the droplet intervals determined by the droplet processing unit to be subject to flow rate calculation within a certain period of time.

[0018] The drip monitoring device further includes a notification control unit that, when the droplet recognition unit recognizes the droplet, causes a light-emitting device to display a light to notify the recognition of the droplet.

[0019] Furthermore, when the droplet interval is less than the processable period, the droplet processing unit does not execute the process of determining the target of flow rate calculation. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide an infusion monitoring device that can accurately measure the interval between drops. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a diagram showing an overview of an infusion monitoring device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an overview of a control unit. [Figure 3] FIG. 10 is a diagram showing the relationship between droplet intervals and calculation of flow rate. [Figure 4] 10 is a diagram showing the relationship between droplet intervals and calculation of the flow rate when rebounding droplets are recognized as dropping droplets. FIG. [Figure 5] FIG. 10 is a diagram showing the relationship between droplet spacing and calculation of flow rate when bouncing droplets are masked. [Figure 6] 3 is a flowchart showing the flow of processing in the infusion monitoring device according to the first embodiment. [Figure 7] 10A and 10B are diagrams illustrating the relationship between droplet spacing and flow rate calculation when rebound droplets are excluded from the calculation of flow rate. [Figure 8] 10 is a flowchart showing the flow of processing in the infusion monitoring device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment of the present invention will be described in detail with reference to the drawings. As shown in Fig. 1, an infusion monitoring device 1 includes a light-emitting unit 5, a light-receiving unit 6, an amplifier circuit 7, a control unit 8, a control circuit 9, an LED driver 10, an LED 11, an LCD driver 12, and an LCD 13. The infusion monitoring device 1 also includes a power supply (not shown) for supplying power to each component.

[0023] The infusion monitor 1 is a device for monitoring infusions, and is used, for example, during infusion therapy in medical institutions. The infusion is supplied from an infusion bag 2 to an infusion tube and enters an infusion cylinder 3 installed midway along the infusion tube. The infusion monitor 1 monitors the drip of a droplet D (hereinafter simply referred to as a droplet) formed at the drip port of the infusion cylinder 3. The amount of infusion is adjusted by a clamp 4 that opens and closes the midway part of the infusion tube.

[0024] The light emitting unit 5 irradiates light onto the droplets dripping inside the drip tube 3. The light irradiated from the light emitting unit 5 may be visible light or infrared light. In this embodiment, infrared light is used as the light irradiated from the light emitting unit 5. The light emitting unit 5 is composed of, for example, one or more LEDs.

[0025] The light receiving unit 6 is a light receiving element configured to change its output voltage according to the intensity of the received light. For example, the light receiving unit 6 outputs a high output voltage when the intensity of the received light is strong, and outputs a low output voltage when the intensity of the received light is weak.

[0026] The light receiving unit 6 is disposed opposite the light emitting unit 5. The light emitted from the light emitting unit 5 is attenuated as it passes through a droplet and is received by the light receiving unit 6. Because the light is attenuated, the intensity of the received light is weaker, and the output voltage from the light receiving unit 6 is lower than when no droplets pass through. Using this, the infusion monitoring device 1 detects the dripping of a droplet.

[0027] The amplifier circuit 7 amplifies the output voltage from the light receiving unit 6 and outputs it to the control unit 8.

[0028] The control unit 8 is a processor such as a CPU (Central Processing Unit). The control unit 8 may also include a ROM (Read Only Memory) in which a program is stored, a RAM (Random Access Memory) for storing data temporarily required for the CPU to execute the program, and the like. The control circuit 9 controls the light emitting unit 5 in accordance with a control signal from the control unit 8 .

[0029] The LED driver 10 controls the LED 11 in accordance with a control signal from the control unit 8 . An LED (Light Emitting Diode) 11 emits light under the control of an LED driver 10. For example, the LED 11 is controlled so as to light up for a certain period of time when a droplet falls.

[0030] The LCD driver 12 controls the LCD 13 in accordance with a control signal from the control unit 8 . An LCD (Liquid Crystal Display) 13 displays an image under the control of the LCD driver 12. The LCD 13 is controlled to display, for example, the flow rate (mL / h) of the infusion.

[0031] As shown in FIG. 2, the control unit 8 includes an A / D conversion unit 81, a signal change detection unit 82, a droplet recognition unit 83, a droplet processing unit 84, a droplet interval measurement unit 85, a flow rate calculation unit 86, and a notification control unit 87.

[0032] The A / D conversion unit 81 converts the voltage output from the amplifier circuit 7 from an analog signal to a digital signal (A / D conversion). The signal change detection section 82 detects a change in the signal output from the A / D conversion section 81. That is, the signal change detection section 82 detects a change in the light received by the light receiving section 5 as a change in the signal.

[0033] The droplet recognition unit 83 recognizes the change in the signal detected by the signal change detection unit 82 as a drop of droplets from the infusion bag 2.

[0034] The droplet processing unit 84 sets a mask period during which the change in the signal detected by the signal change detection unit 82 is not recognized as a droplet by the droplet recognition unit 83. Furthermore, the droplet processing unit 84 does not set a mask period if the droplet interval measured by the droplet interval measurement unit 85 (described later) is shorter than the processable period.

[0035] The droplet interval measuring unit 85 measures the droplet interval from when a signal change is detected by the signal change detecting unit 82 to when the next signal change is detected. Here, the signal change and the next signal change are signal changes corresponding to droplets recognized by the droplet recognition unit 83, respectively. In other words, the droplet interval measuring unit 85 measures the interval between signal changes corresponding to droplets recognized by the droplet recognition unit 83 as the droplet interval.

[0036] The flow rate calculation unit 86 calculates the flow rate of the infusion based on the droplet intervals between droplets recognized by the droplet recognition unit 83. The flow rate calculation unit 86 also calculates the flow rate of the infusion based on the droplet intervals determined by the droplet processing unit 84 to be subject to flow rate calculation.

[0037] When the droplet recognition unit 83 recognizes a droplet, the notification control unit 87 outputs a control signal to the LED driver 10 to cause the LED 11 to emit light in order to notify the recognition of the droplet.

[0038] Next, the operation of the control unit 8 when a mask period is not set will be described in detail with reference to Figures 3 to 5. Figure 3 is a diagram showing the relationship between droplet intervals and calculation of the flow rate.

[0039] First, the droplet recognition unit 83 recognizes the change in the signal detected by the signal change detection unit 82 as a drop of droplets from the infusion bag 2. The droplet interval measurement unit 85 measures the time from when a signal change detected by the signal change detection unit 82 and recognized as a droplet by the droplet recognition unit 83 is detected to when the next signal change is detected, and extracts the measured time as the droplet interval. For example, as shown in FIG. 3, the droplet interval measurement unit 85 extracts the droplet intervals of droplets corresponding to the five signal changes detected by the signal change detection unit 82 and recognized by the droplet recognition unit 83.

[0040] The flow rate calculation unit 86 calculates the flow rate of the infusion based on the droplet intervals of the five droplets extracted by the droplet interval measurement unit 85.

[0041] Specifically, the flow rate calculation unit 86 calculates the flow rate of the infusion using the following formula (1) (when an infusion set that drips 1 mL in 20 drops is used). Flow rate calculation value A1 (mL / h) = 1 (mL) × 5 (droplets) / 20 (droplets) / (droplet interval (seconds)) × 3600 (seconds) (1) Here, the droplet spacing is as shown in Figure 3. Droplet interval = Droplet interval D1 + Droplet interval D2 + Droplet interval D3 + Droplet interval D4 + Droplet interval D5 (2) It is shown as follows.

[0042] Furthermore, the control unit 8 updates the drop interval used for calculating the flow rate with each drop from the sixth drop onwards, and calculates the infusion flow rate. Specifically, the control unit 8 calculates a flow rate calculation value A2 based on the updated drop interval for the second to sixth drops, and calculates a flow rate calculation value A3 based on the updated drop interval for the third to seventh drops.

[0043] However, when the droplets falling inside the drip tube 3 hit the liquid surface, the droplets that bounce off the liquid surface may reach the positions of the light-emitting unit 5 and the light-receiving unit 6. In this case, the drip monitoring device 1 detects both the droplets falling from above and the droplets that bounce off from below, and recognizes them as dripping droplets.

[0044] FIG. 4 is a diagram showing the relationship between droplet intervals and flow rate calculations when rebounding droplets are recognized as actual droplets. In FIG. 4, all droplets fall at equal intervals. In this state, if the third droplet rebounds from the liquid surface, the drip monitoring device 1 will recognize the rebounding droplet as an actual droplet. Therefore, the drip monitoring device 1 extracts five droplet intervals without waiting for the sixth droplet, and calculates flow rate calculation values ​​B1, B2, B3, etc. that are greater than the actual flow rate.

[0045] As a result, the calculated flow rate value displayed on the LCD 13 of the drip monitoring device 1 will be greater than the actual flow rate value. Also, if the interval between droplets (flow rate) is relatively slow and the droplets bounce off the liquid surface as described above, it will take several tens of seconds for the drip monitoring device 1 to update the calculated flow rate value displayed on the LCD 13 to the correct value.

[0046] Therefore, the drip monitoring device 1 according to the first embodiment sets a mask period during which the droplet recognition unit 83 does not recognize the signal change detected by the signal change detection unit 82 as a droplet. This allows the drip monitoring device 1 to prevent the short droplet intervals caused by the rebounding droplets from affecting the flow rate calculation value and the display on the LCD 13.

[0047] 5 is a diagram showing the relationship between droplet spacing and flow rate calculation when masking rebound droplets. As shown in Fig. 5, droplet processing unit 84 sets a masking period during which the droplet recognition unit 83 does not recognize the signal change detected by signal change detection unit 82 as a droplet.

[0048] Specifically, the droplet processing unit 84 sets a mask period during which the droplet recognition unit 83 does not recognize a change in the signal detected by the signal change detection unit 82 as a droplet, based on the droplet interval measured immediately before. For example, the droplet processing unit 84 sets a period that is 50% of the droplet interval measured immediately before as the mask period. As a result, if a rebound droplet is less than 50% of the previous droplet interval, the droplet recognition unit 83 does not recognize the rebound droplet as a droplet. Furthermore, the droplet processing unit 84 may set a period that is 50% of the average value of the five droplet intervals measured immediately before as the mask period. Furthermore, the droplet processing unit 84 may preset a predetermined mask period as an initial value.

[0049] The droplet interval measurement unit 85 measures the time from when a signal change is detected by the signal change detection unit 82 to when the next signal change is detected, and extracts the measured time as the droplet interval. Here, the droplet interval measurement unit 85 measures the interval between signal changes corresponding to droplets recognized by the droplet recognition unit 83 as the droplet interval. In other words, signal changes corresponding to rebound droplets detected during the set mask period are not recognized as droplets by the droplet recognition unit 83, and are therefore not used in measuring the droplet interval.

[0050] In the example shown in Figure 5, a rebound droplet occurs at the third droplet, but a signal change corresponding to the rebound droplet is detected by signal change detection unit 82 within the mask period. Therefore, droplet recognition unit 83 does not recognize the rebound droplet, shown as droplet interval D3-1 in Figure 5, as a droplet. Therefore, the droplet intervals that are the subject of flow rate calculation by flow rate calculation unit 86 are droplet interval D1, droplet interval D2, droplet interval D3-2, droplet interval D4, and droplet interval D5.

[0051] Therefore, the flow rate calculation unit 86 calculates a flow rate calculation value C1 as the infusion flow rate using the drop interval D1, drop interval D2, drop interval D3-2, drop interval D4, and drop interval D5, and the above-mentioned equations (1) and (2).

[0052] Furthermore, for the sixth drop, the flow rate calculation unit 86 updates the drop interval to a new drop interval D1 to D5 and calculates a flow rate calculation value C2 as the infusion flow rate. This allows the drip monitoring device 1 to calculate an appropriate flow rate value and display the calculated flow rate value on the LCD 13.

[0053] In the examples of Figures 3 to 5 described above, the flow rate calculation unit 86 calculates the flow rate of the infusion based on the droplet intervals of droplets recognized by the droplet recognition unit 83 within a certain period (for example, five droplet intervals), but the number of droplet intervals is not limited to this and may be less than five or more than six.

[0054] Furthermore, the droplet processor 84 does not set a mask period if the droplet interval is less than the processable period (for example, 30% of the previous droplet interval). This allows the drip monitoring device 1 to calculate the infusion flow rate without setting a mask period when the droplet interval is very short.

[0055] FIG. 6 is a flowchart showing the flow of processing in the infusion monitoring device 1 according to the first embodiment. In step S1, the light receiving unit 6 receives the light emitted from the light emitting unit 5. In step S2, the amplifier circuit 7 amplifies the output voltage from the light receiving unit 6.

[0056] In step S3, the A / D conversion unit 81 A / D converts the voltage output from the amplifier circuit . In step S 4 , the signal change detection unit 82 detects a change in the signal output from the A / D conversion unit 81 .

[0057] In step S5, when the signal change detection unit 82 detects a signal change, the droplet processing unit 84 determines whether the detection of the signal change is within the mask period. If it is determined that the detection of the signal change is within the mask period (YES), the signal change detected by the signal change detection unit 82 is not recognized by the droplet recognition unit 83, and the process returns to step S1 again. On the other hand, if it is determined that the detection of the signal change is not within the mask period (NO), the process proceeds to step S6. Note that if a mask period has not been set, in step S5 the droplet processing unit 84 determines that the detection of the signal change is not within the mask period (NO).

[0058] In step S6, the droplet recognition unit 83 recognizes the change in the signal detected by the signal change detection unit 82 as a dripping of a droplet from the infusion bag 2.

[0059] In step S7, the droplet interval measurement unit 85 measures the interval between signal changes detected by the signal change detection unit 82 and recognized as droplets by the droplet recognition unit 83 as the droplet interval.

[0060] In step S8, the droplet processor 84 determines whether the droplet interval is equal to or greater than the processable period T1 (for example, 30% of the previous droplet interval). If the droplet interval is equal to or greater than the processable period T1 (YES), the process proceeds to step S9. On the other hand, if the droplet interval is less than the processable period T1 (NO), the process proceeds to step S10.

[0061] In step S9, droplet processing unit 84 sets a mask period during which the droplet recognition unit 83 does not recognize the signal change detected by signal change detection unit 82 as a droplet, based on the droplet interval measured by droplet interval measurement unit 85. Then, the process proceeds to step S11.

[0062] In step S10, if the droplet interval is less than the processable period T1, the droplet processor 84 does not set a mask period, and then the process proceeds to step S11. In step S11, the flow rate calculation unit 86 calculates the flow rate of the infusion based on the droplet intervals recognized by the droplet recognition unit 83 (for example, the intervals between five droplets).

[0063] In step S12, when the droplet recognition unit 83 recognizes a droplet, the notification control unit 87 outputs a control signal to the LED driver 10 to cause the LED 11 to emit light in order to notify the recognition of the droplet. After that, each time a droplet is recognized, the control unit 8 updates the droplet interval used for flow rate calculation to a new droplet interval by one, and calculates the flow rate of the infusion.

[0064] [Second embodiment] Next, a drip monitoring device 1 according to a second embodiment will be described. The drip monitoring device 1 according to the second embodiment differs from the first embodiment mainly in the processing of the droplet processing unit 84. In detail, the drip monitoring device 1 according to the second embodiment differs from the drip monitoring device 1 according to the first embodiment in that, instead of the mask period set in the first embodiment, the drip monitoring device 1 according to the second embodiment performs processing to exclude droplets with short droplet intervals from being measured for droplet intervals.

[0065] In the second embodiment, if the drop interval measured by the drop interval measurement unit 85 is equal to or longer than a predetermined period, the drop processing unit 84 determines that the drop interval is subject to calculation of the infusion flow rate, and if the drop interval is shorter than the predetermined period, the drop interval measurement unit 85 determines that the signal change detected later, of the two signal changes used to measure the drop interval, is not subject to measurement of the drop interval by the drop interval measurement unit 85. This allows the infusion monitoring device 1 to prevent short drop intervals due to bouncing drops from affecting the flow rate calculation value and the display on the LCD 13.

[0066] 7 is a diagram showing the relationship between the drop interval and the calculation of the flow rate when the rebounded drops are excluded from the drop interval measurement. As shown in FIG. 7, when the drop interval is equal to or longer than a predetermined period, the drop processing unit 84 determines that the drop interval is included in the calculation of the infusion flow rate, and when the drop interval is shorter than the predetermined period, it determines that the change in the signal detected later, of the two signal changes used to measure the drop interval, is excluded from the drop interval measurement.

[0067] Specifically, droplet processor 84 sets a predetermined period (for example, 50% of the previous droplet interval) based on the previous droplet interval, and if the droplet interval is equal to or greater than the predetermined period (50% of the previous droplet interval), determines that the droplet interval is subject to infusion flow rate calculation. On the other hand, if the droplet interval is less than the predetermined period (50% of the previous droplet interval), droplet processor 84 determines that the signal change detected later, of the two signal changes used to measure the droplet interval, is not subject to measurement of the droplet interval by droplet interval measurement unit 85.

[0068] In the example shown in Figure 7, a rebound droplet occurs at the third drop, but the droplet interval D3-1 due to the rebound droplet is less than 50% of the previous droplet interval. Therefore, of the two signal changes used to measure the droplet interval D3-1, the droplet processing unit 84 determines that the later detected signal change (i.e., the signal change corresponding to the rebound droplet) is not to be measured by the droplet interval measurement unit 85. As a result, the droplet interval D3-1 due to the rebound droplet is not to be calculated in the flow rate calculation. Therefore, the droplet intervals that are to be calculated in the flow rate calculation unit 86 are the droplet interval D1, droplet interval D2, droplet interval D3-2, droplet interval D4, and droplet interval D5.

[0069] Therefore, the flow rate calculation unit 86 calculates a flow rate calculation value C1 as the infusion flow rate using the drop interval D1, drop interval D2, drop interval D3-2, drop interval D4, and drop interval D5, and the above-mentioned equations (1) and (2).

[0070] Furthermore, for the sixth drop, the flow rate calculation unit 86 updates the drop interval to a new drop interval D1 to D5 and calculates a flow rate calculation value C2 as the infusion flow rate. This allows the drip monitoring device 1 to calculate an appropriate flow rate value and display the calculated flow rate value on the LCD 13.

[0071] In the example of Figure 7 described above, the flow rate calculation unit 86 calculates the flow rate of the infusion based on the drop intervals determined by the droplet processing unit 84 to be subject to flow rate calculation within a certain period (e.g., five drop intervals), but the number of drop intervals is not limited to this and may be less than five or more than six.

[0072] Furthermore, the droplet processor 84 does not execute the process of determining whether a droplet interval is subject to flow rate calculation if the droplet interval is less than the processable period T1 (for example, 30% of the previous droplet interval). This allows the drip monitoring device 1 to calculate the flow rate of the infusion without executing the process of excluding short droplet intervals from the flow rate calculation when the droplet interval is very short.

[0073] FIG. 8 is a flowchart showing the flow of processing in the infusion monitoring device 1 according to the second embodiment. In step S21, the light receiving unit 6 receives the light emitted from the light emitting unit 5. In step S22, the amplifier circuit 7 amplifies the output voltage from the light receiving unit 6.

[0074] In step S23, the A / D conversion unit 81 A / D converts the voltage output from the amplifier circuit . In step S24, the signal change detection unit 82 detects a change in the signal output from the A / D conversion unit 81.

[0075] In step S25, the droplet recognition unit 83 recognizes the change in the signal detected by the signal change detection unit 82 as a dripping of a droplet from the infusion bag 2.

[0076] In step S26, when the droplet recognition unit 83 recognizes a droplet, the notification control unit 87 outputs a control signal to the LED driver 10 to cause the LED 11 to emit light in order to notify the recognition of the droplet.

[0077] In step S27, droplet interval measurement unit 85 measures the interval between signal changes detected by signal change detection unit 82 and recognized as droplets by droplet recognition unit 83 as the droplet interval.

[0078] In step S28, the droplet processor 84 determines whether the droplet interval is equal to or greater than the processable period T1 (for example, 30% of the previous droplet interval). If the droplet interval is equal to or greater than the processable period T1 (YES), the process proceeds to step S30. On the other hand, if the droplet interval is less than the processable period T1 (NO), the process proceeds to step S29.

[0079] In step S29, if the droplet interval is less than the processable period T1, the droplet processor 84 does not execute the process of determining the target of flow rate calculation. That is, the droplet processor 84 determines the droplet interval as the target of flow rate calculation, and the process proceeds to step S33.

[0080] In step S30, the droplet processor 84 determines whether the droplet interval is equal to or greater than a predetermined period T2 (e.g., 50% of the previous droplet interval). If the droplet interval is equal to or greater than the predetermined period T2 (YES), the process proceeds to step S31. On the other hand, if the droplet interval is less than the predetermined period T2 (NO), the process proceeds to step S32.

[0081] In step S31, the droplet processor 84 determines that the droplet interval is a target for calculating the infusion flow rate, and then the process proceeds to step S33. In step S32, the droplet processing unit 84 determines that the change in the signal detected later, of the two signal changes used to measure the droplet interval, is not subject to measurement of the droplet interval, and then the processing returns to step S21 again.

[0082] In step S33, the flow rate calculation unit 86 calculates the flow rate of the infusion based on the droplet interval determined by the droplet processing unit 84 to be subject to flow rate calculation, or the droplet interval determined by the droplet processing unit 84 in step S28 to be shorter than the processable period T1. Thereafter, each time a droplet falls, the control unit 8 updates the droplet interval used for flow rate calculation to a new droplet interval, and calculates the flow rate of the infusion.

[0083] As described above, the drip monitoring device 1 comprises an emitter 5 that irradiates light onto droplets, a light receiver 6 that receives the light irradiated from the emitter 5, an amplifier circuit 7 that amplifies the output voltage from the light receiver 6, an A / D converter 81 that A / D converts the voltage output from the amplifier circuit 7, a signal change detector 82 that detects changes in the signal output from the A / D converter 81, a droplet recognition unit 83 that recognizes the signal changes detected by the signal change detector 82 as droplets, a droplet processing unit 84 that sets a mask period during which the signal changes detected by the signal change detector 82 are not recognized as droplets by the droplet recognition unit 83, and a droplet interval measurement unit 85 that measures the interval between signal changes recognized as droplets by the droplet recognition unit 83 as a droplet interval.

[0084] As a result, after detecting a droplet, the drip monitor 1 sets a mask period that varies depending on the flow rate of the droplet, and does not recognize the rebound droplets detected during the mask period as actual droplets. Therefore, the drip monitor 1 can accurately measure the droplet interval without the short interval between droplets caused by the rebound droplets affecting the calculated value of the infusion flow rate.

[0085] The drip monitoring device 1 also includes a flow rate calculation unit 86 that calculates the flow rate of the infusion based on the drop interval measured by the drop interval measurement unit 85. This allows the flow rate of the infusion to be accurately calculated based on the accurately measured drop interval.

[0086] Furthermore, the droplet processing unit 84 sets a mask period during which droplets are not recognized by the droplet recognition unit 83 based on the droplet interval measured immediately before. This allows the drip monitoring device 1 to accurately calculate the flow rate of the infusion without recognizing rebound droplets as dripping droplets during the mask period based on the droplet interval measured immediately before.

[0087] Furthermore, the flow rate calculation unit 86 calculates the flow rate of the infusion based on the droplet intervals between droplets recognized within a certain period (e.g., five droplet intervals) by the droplet recognition unit 83. This allows the infusion monitoring device 1 to accurately calculate the flow rate of the infusion using the droplet intervals recognized within a certain period (e.g., five droplet intervals).

[0088] The drip monitoring device 1 further includes a notification control unit 87 that causes the LED 11 to emit light to notify the user of the recognition of a droplet when the droplet recognition unit 83 recognizes the droplet. This allows the drip monitoring device 1 to notify the user of the recognition of the droplet.

[0089] Furthermore, the droplet processor 84 does not set a mask period if the droplet interval is less than the processable period (for example, 30% of the previous droplet interval). This allows the drip monitoring device 1 to calculate the infusion flow rate without performing processing to exclude short droplet intervals from the flow rate calculation when the droplet interval is very short.

[0090] Furthermore, in the drip monitoring device 1 of the second embodiment, if the drop interval is equal to or longer than a predetermined period, the droplet processing unit 84 determines that the drop interval is subject to calculation of the infusion flow rate, and if the drop interval is shorter than the predetermined period, the droplet interval measurement unit 85 determines that the change in the signal detected later, of the two signal changes used to measure the drop interval, is not subject to measurement of the drop interval, and the flow rate calculation unit 86 calculates the infusion flow rate based on the drop interval determined by the droplet processing unit 84 to be subject to flow rate calculation. This allows the drip monitoring device 1 to accurately calculate the infusion flow rate without allowing short drop intervals due to bouncing droplets to affect the calculated value of the infusion flow rate.

[0091] The droplet processor 84 also sets the predetermined period based on the most recently measured droplet interval, allowing the infusion monitoring device 1 to use the most recently measured droplet interval to determine whether or not to include the interval in the calculation of the infusion flow rate.

[0092] Furthermore, the flow rate calculation unit 86 calculates the flow rate of the infusion based on the droplet intervals between droplets recognized within a certain period (e.g., five droplet intervals) by the droplet recognition unit 83. This allows the infusion monitoring device 1 to accurately calculate the flow rate of the infusion using the droplet intervals recognized within a certain period (e.g., five droplet intervals).

[0093] Furthermore, the droplet processor 84 does not execute the process of determining whether a drop interval is subject to flow rate calculation if the drop interval is less than the processable period (for example, 30% of the previous drop interval). When the drop interval is very short, the drip monitoring device 1 can calculate the infusion flow rate without executing the process of excluding short drop intervals from the flow rate calculation.

[0094] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Furthermore, the effects described in the present embodiments are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the present embodiments.

[0095] For example, in the first embodiment, the control by the notification control unit 87 to cause the LED 11 to emit light is described in step S12, but this is not limiting. The control by the notification control unit 87 to cause the LED 11 to emit light may be performed when a droplet is recognized by the droplet recognition unit 83, and for example, the control by the notification control unit 87 to cause the LED 11 to emit light may be performed between step S6 and step S7.

[0096] In the second embodiment, the signal change detection unit 82 and the droplet recognition unit 83 are described as different functional units, but this is not limiting. That is, the signal change detection unit and the droplet recognition unit may be configured as a single functional unit, and a change in a predetermined signal output from the A / D conversion unit 81 may be recognized as a droplet. [Explanation of symbols]

[0097] 1 Infusion monitoring device 2 infusion bags 3 Drip tube 4. Klemme 5 Light-emitting part 6 Light receiving part 7 Amplification circuit 8 Control Unit 9 Control Circuit 10 LED drivers 11 LED 12 LCD Driver 13 LCD 81 A / D conversion section 82 Signal change detection unit 83 Droplet recognition section 84 Droplet processing section 85 Droplet interval measuring unit 86 Flow rate calculation section 87 Notification control section

Claims

1. An infusion monitoring device for monitoring the dripping of infusion droplets in an infusion tube, a light emitting unit that irradiates the droplets with light; a light receiving unit that receives light emitted from the light emitting unit; a signal change detection unit that detects a change in the light received by the light receiving unit as a change in a signal; a droplet recognition unit that recognizes the change in the signal detected by the signal change detection unit as the droplet; a droplet processing unit that sets a mask period during which the droplet recognition unit does not recognize the change in the signal detected by the signal change detection unit as the droplet; a droplet interval measurement unit that measures the interval between changes in the signal recognized as droplets by the droplet recognition unit as a droplet interval; the droplet processing unit does not set the mask period when the droplet interval is shorter than a processable period; Intravenous drip monitoring device.

2. The drip monitoring device according to claim 1 , wherein the droplet processing unit sets a mask period during which the droplet recognition unit does not recognize the droplets based on the droplet interval measured immediately before.

3. 3. The drip monitoring device according to claim 1, further comprising a flow rate calculation unit that calculates the flow rate of the infusion based on the drip interval measured by the drip interval measurement unit.

4. The infusion monitoring device according to claim 3 , wherein the flow rate calculation unit calculates the flow rate of the infusion based on the droplet intervals between the droplets recognized by the droplet recognition unit within a certain period of time.

5. The drip monitoring device according to any one of claims 1 to 4, further comprising an alarm control unit that causes a light emitting device to emit light when the droplet is recognized by the droplet recognition unit to notify the recognition of the droplet.

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