Liquid amount measurement device, infusion flow rate measurement system, urine flow rate measurement system, computer program, liquid amount measurement method, infusion flow rate measurement method, and urine flow rate measurement method

Abstract

Provided are a liquid amount measurement device, an infusion flow rate measurement system, a urine flow rate measurement system, a computer program, a liquid amount measurement method, an infusion flow rate measurement method, and a urine flow rate measurement method that make it possible to accurately measure the amount of liquid in a wide flow rate range regardless of a proper flow rate range.　This liquid amount measurement device comprises a control unit and a detection unit that detects the number of drops of a liquid in a drip chamber. The control unit calculates the flow rate of the liquid on the basis of the number of drops detected by the detection unit, selects a correction unit according to the calculated flow rate from among a plurality of correction units, and calculates a corrected flow rate or a corrected cumulative amount of the liquid using the selected correction unit.

Description

Fluid volume measuring device, infusion flow rate measuring system, urine flow rate measuring system, computer program, fluid volume measuring method, infusion flow rate measuring method, and urine flow rate measuring method

[0001] The present disclosure relates to a fluid volume measurement device, an infusion flow rate measurement system, a urine flow rate measurement system, a computer program, a fluid volume measurement method, an infusion flow rate measurement method, and a urine flow rate measurement method.

[0002] Patent Document 1 discloses a drip tube that is composed of a container body and a lid, and the container body has a transparent, cylindrical drip section for checking the dripping of liquid, and a cylindrical liquid storage section for storing the liquid.

[0003] Japanese Patent Application Laid-Open No. 2001-29465

[0004] When setting the infusion flow rate, the interval between droplets at the drip section is checked. While research into droplet flow rate and flow rate changes due to inclination of the drip tube and the development of devices for measuring droplet volume are progressing, the number of droplets per mL of infusion set is specified by standards for adult and pediatric drip tubes, and the appropriate flow rate range for the drip tube is predetermined. This is because droplet volume changes depending on the flow rate, and when the infusion flow rate is high, the droplet drip speed increases, resulting in missed detections. For this reason, there is a demand for an infusion tube that can be used regardless of the appropriate flow rate range.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a fluid volume measuring device, an infusion flow rate measuring system, a urine flow rate measuring system, a computer program, a fluid volume measuring method, an infusion flow rate measuring method, and a urine flow rate measuring method that can measure fluid volume with high accuracy over a wide flow rate range regardless of the appropriate flow rate range.

[0006] (1) A liquid volume measuring device according to the present disclosure includes a control unit and a detection unit that detects the number of droplets dropped from a drip tube, and the control unit calculates a flow rate of the liquid based on the number of droplets detected by the detection unit, selects a correction unit from among a plurality of correction units that corresponds to the calculated flow rate, and calculates a corrected flow rate or corrected integrated amount of the liquid using the selected correction unit. Here, an embodiment of the present disclosure is as follows: (2) In the liquid volume measuring device of (1) above, the plurality of correction units are associated with a plurality of flow rate range segments, and the control unit selects a correction unit that corresponds to a flow rate range segment that includes the calculated flow rate. (3) In the liquid volume measuring device of (2) above, the correction unit includes a correction formula that converts the calculated flow rate to a corrected flow rate, and the control unit calculates the corrected flow rate based on the calculated flow rate using the correction formula that corresponds to the flow rate range segment that includes the calculated flow rate. (4) In the liquid volume measuring device of (2) or (3) above, the correction unit includes a conversion formula for converting the calculated flow rate into a volume per drop, and the control unit calculates a corrected volume by correcting the volume per drop for the calculated flow rate using a conversion formula corresponding to a flow rate range section, and calculates the corrected flow rate based on the detected number of drops and the corrected volume. (5) In the liquid volume measuring device of any one of (2) to (4) above, the correction unit includes a conversion formula for converting the calculated flow rate into a volume per drop, and the control unit calculates a corrected volume by correcting the volume per drop for the calculated flow rate using a conversion formula corresponding to a flow rate range section that includes the calculated flow rate, and calculates the corrected integrated amount for the second time point by adding the corrected flow rate calculated based on the number of drops and the corrected volume detected during an update time from the first time point to a corrected integrated amount for the first time point. (6) In any one of the fluid volume measuring devices described above in (2) to (5), the plurality of flow rate range segments are associated with each type of drip tube or each medication used, and the control unit receives a selection of the type of drip tube or each medication used and selects a flow rate range segment corresponding to the selected type of drip tube or each medication used. (7) In any one of the fluid volume measuring devices described above in (1) to (6), the control unit selects the correction unit each time the corrected flow rate or the corrected integrated amount is calculated. (8) An infusion flow rate measurement system includes the aforementioned fluid volume measuring device.(9) A urine flow measurement system includes the aforementioned fluid volume measurement device. (10) A computer program causes a computer to execute a process that calculates a liquid flow rate based on the number of droplets detected by a detection unit that detects the number of droplets from a drip tube, selects a correction formula from multiple correction formulas that corresponds to the calculated flow rate, and calculates a corrected flow rate or corrected integrated volume of the liquid using the selected correction formula. (11) A fluid volume measurement method calculates a liquid flow rate based on the number of droplets detected by a detection unit that detects the number of droplets from a drip tube, selects a correction unit from multiple correction units that corresponds to the calculated flow rate, and calculates a corrected flow rate or corrected integrated volume of the liquid using the selected correction unit. (12) A method for measuring infusion flow rate uses the aforementioned fluid volume measurement method. (13) A method for measuring urine flow rate uses the aforementioned fluid volume measurement method.

[0007] According to the present disclosure, the amount of liquid can be measured with high accuracy over a wide range of flow rates, regardless of the appropriate flow rate range.

[0008] 1 is a diagram showing an example of the configuration of a liquid volume measurement device of this embodiment; FIG. 2 is a diagram showing an example of the configuration of a control unit; FIG. 3 is a diagram showing an example of a dead time of a measurement unit; FIG. 4 is a diagram showing an example of a dead time of a measurement unit; FIG. 5 is a diagram showing an example of flow rate correction by a liquid volume measurement device of this embodiment; FIG. 6 is a diagram showing an example of a correction formula; FIG. 7 is a diagram showing an example of flow rate correction using the correction formula; FIG. 8 is a diagram showing an example of a change in droplet volume derived from flow rate; FIG. 9 is a diagram showing an example of a processing procedure for flow rate correction by a liquid volume measurement device of this embodiment; FIG. 10 is a diagram showing an example of a processing procedure for integrated volume correction by a liquid volume measurement device of this embodiment; FIG. 11 is a diagram showing an example of an infusion flow rate measurement system of this embodiment; FIG. 12 is a diagram showing an example of a urine flow measurement system of this embodiment; FIG. 13 is a diagram showing an example of the configuration of a urinary catheterization management device; FIG. 14 is a diagram showing an example of a processing procedure for a urinary catheterization management device.

[0009] An embodiment of the present disclosure will be described below. FIG. 1 is a diagram showing an example of the configuration of a liquid volume measuring device according to this embodiment. The liquid volume measuring device according to this embodiment can be used as both a drip tube and a flow sensor. The liquid volume measuring device has a configuration similar to that of a drip tube. The liquid volume measuring device includes a cylindrical container body having a transparent, cylindrical dripping portion 10, and a cap portion 11. A tube 21 for flowing liquid 30 is connected to the upper portion of the container body through the cap portion 11. The lower portion of the container body has a storage portion for temporarily storing liquid 30, and the liquid 30 stored in the storage portion flows through tube 22. The liquid 30 may be a drug or a specimen such as urine.

[0010] The liquid volume measuring device includes a measurement unit 40 that can be detachably attached to the dripping unit 10. The measurement unit 40 includes a light-emitting unit 41 and a light-receiving unit 42 that are arranged opposite each other across the longitudinal axis of the dripping unit 10 (the direction in which the droplets fall and pass), as well as a control unit 50. The light-emitting unit 41 continuously irradiates the required light toward the light-receiving unit 42. The light-receiving unit 42 can receive the light irradiated by the light-emitting unit 41. When a droplet drips from the dripping unit 10, the light irradiated from the light-emitting unit 41 is blocked by the droplet, and the light-receiving unit 42 cannot receive the light. The light-receiving unit 42 outputs a light-receiving signal corresponding to the received light to the control unit 50.

[0011] 2 is a diagram showing an example of the configuration of the control unit 50. The control unit 50 includes a control unit 51 that controls the entire control unit 50, a communication unit 52, a detection unit 53, a display unit 54, an operation unit 55, a timer unit 56, a memory 57, and a storage unit 58.

[0012] The control unit 51 may be configured by incorporating a required number of CPUs (Central Processing Units), MPUs (Micro-Processing Units), GPUs (Graphics Processing Units), etc. The control unit 51 may also be configured by combining DSPs (Digital Signal Processors), FPGAs (Field-Programmable Gate Arrays), etc. The control unit 51 can control the operations of the light-emitting unit 41 and the light-receiving unit 42.

[0013] The communication unit 52 includes a communication module and has a function of communicating with external devices via a communication network such as an in-hospital network.

[0014] The detector 53 includes an amplifier, amplifies the light-receiving signal acquired from the light-receiving unit 42, and detects the number of droplets dropped from the dripping unit 10 (drip tube) based on the amplified light-receiving signal. The detector 53 can set a sampling period for detecting the number of droplets, and shortening the sampling period can shorten the dead time. Details of the dead time will be described later.

[0015] The display unit 54 can be configured with a liquid crystal panel, an organic EL (Electro Luminescence) display, etc. Instead of the display unit 54, an external display device may be provided.

[0016] The operation unit 55 is configured with a touch panel or the like, and allows the user to operate icons displayed on the display unit 54, move and operate a cursor, input characters, etc. The operation unit 55 may also be a mouse or a keyboard.

[0017] The timer unit 56 can measure time under the control of the control unit 51. The timer unit 56 outputs the measured time to the control unit 51.

[0018] The storage unit 58 can be configured with a semiconductor memory or the like, and stores a computer program 60 (program product), a correction unit 61, and required information. The correction unit 61 will be described in detail later.

[0019] The computer program 60 is an application program that defines the operation of the liquid volume measuring device. The computer program 60 may be downloaded from an external device via the communication unit 52 and stored in the storage unit 58. Alternatively, the computer program 60 may be stored in the storage unit 58 after being read by a storage medium reader from a storage medium (for example, an optically readable disk storage medium such as a CD-ROM).

[0020] The memory 57 can be configured with semiconductor memory such as SRAM (Static Random Access Memory), DRAM (Dynamic Random Access Memory), flash memory, etc. A computer program 60 can be loaded into the memory 57, and the control unit 51 can execute the computer program 60. The control unit 51 can execute processing defined by the computer program 60. In other words, processing by the control unit 51 is also processing by the computer program 60.

[0021] FIG. 3 is a diagram showing an example of the dead time of the measurement unit 40. The dead time is the interval from when the measurement unit 40 detects the drop of a droplet to when it can detect the next droplet, and is the time during which the measurement unit 40 cannot detect a droplet. In FIG. 3, the drop time is a waveform indicating the drop detection, and the rising point of the waveform corresponds to the point when the light receiving unit 42 cannot receive light, indicating the point when the drop is detected. The dead time is represented by the time the waveform is in a high (H) level state; in the example of FIG. 3A, the dead time is T1, and in FIG. 3B, it is T2.

[0022] 3A is a comparative example showing a case where the dead time T1 is relatively long. As shown in FIG. 3A, when a drop is detected, the dead time T1 begins. Even if a drop is detected next, if the detection occurs within the dead time T1, the measurement unit 40 will not be able to detect the drop, resulting in a missed detection. Thus, even if a drop is detected during the dead time T1, the detection will not be accurate, and the missed detection will result in an error in the number of drops detected. When a missed detection occurs in the number of drops, the actual flow rate relative to the measured flow rate will not be consistent.

[0023] FIG. 3B shows the case of this embodiment. In FIG. 3B, the dead time T2 is set to a time shorter than the dead time T1. As shown in FIG. 3B, when a drop is detected, the dead time T2 begins. When the next drop is detected, the dead time T2 has ended because the dead time T2 is set to a short time. This allows the next drop to be detected. As described above, in this embodiment, the dead time is set to be shorter than the drop interval, so drops can be detected without omission, preventing missed detections and determining a single actual flow rate for a measured flow rate. This reduces measurement errors and makes it possible to correct the flow rate or integrated amount of liquid, as described below.

[0024] Next, correction of the liquid volume (flow rate or cumulative volume) will be described.

[0025] The applicant has discovered that flow rate measurements using drip tubes contain errors due to changes in droplet volume caused by the flow rate, as well as errors specific to the type of drip tube and the drug used. Therefore, in this embodiment, multiple appropriate correction methods (correction units) are defined depending on the type of drip tube, the drug used, and the flow rate range of the liquid, such as the drug. The correction method is selected based on the type of drip tube, drug, and measured flow rate used to correct the flow rate and the integrated amount. This is explained in detail below.

[0026] FIG. 4 is a diagram showing an example of flow rate correction by the liquid volume measuring device of this embodiment. As described above, when correcting the liquid flow rate, an appropriate correction method can be selected depending on the type of drip tube, the drug used, and the range of measured flow rates. As shown in FIG. 4, in this embodiment, an appropriate correction method can be selected by dividing into the type of drip tube, the drug used, the number of flow rate categories, the flow rate range, and flow rate correction formulas f and g corresponding to the flow rate range. The correction unit 61 described above has a configuration as shown in FIG. 4.

[0027] For example, the types of drip tubes are D1, D2, .... Here, for convenience, the types of drip tubes are represented by symbols such as D1, D2, .... The drugs used for drip tube D1 are represented by symbols such as X1, X2, .... For drug X1 used, the number of flow rate categories is N1, and the flow rate ranges are F1, F2, F3. The number of flow rate categories is the number of categories when dividing the usable flow rate range into multiple flow rate categories. In the example of Figure 4, N1 = 3, but N1 may be greater than 3. The flow rate range is the flow rate range for each flow rate category, and the usable flow rate range is divided into flow rate ranges F1, F2, F3.

[0028] Flow rate correction formula f is intended to correct measurement errors depending on the flow rate range, primarily due to the type of drip tube and the drug used, while flow rate correction formula g is intended to correct measurement errors depending on the flow rate range, primarily due to changes in droplet volume with flow rate. In other words, flow rate correction formula f and flow rate correction formula g can correct measurement errors depending on the flow rate range, which are caused by the fact that the appropriate flow rate range is predetermined for each type of drip tube, and that the droplet volume at a certain flow rate may change due to different viscosities depending on the type of drug. In the example of Figure 4, the flow rates for flow rate ranges F1, F2, and F3 may be corrected using correction formulas f1, f2, and f3, respectively, or the flow rates may be corrected using correction formulas g1, g2, and g3.

[0029] Similarly, for the drug X2, the number of flow rate sections is N2 and the flow rate ranges are F11, F12, ..., F15. For each of the flow rate ranges F11, F12, ..., F15, the flow rate may be corrected using correction formulas f1, f12, ..., f15, or g11, g12, ..., g15. The same applies to the other drugs used and the other drip tubes D2, ....

[0030] FIG. 5 is a diagram showing an example of a correction formula. As shown in FIG. 5, the input variable of the flow rate correction formula f is x, and the output variable is y. The input variable x is the flow rate before correction, and the output variable y is the corrected flow rate (the flow rate after correction). The correction formula f1 for the flow rate range F1 is y=a1·x 2 + a2 x + a3, and the correction formula f2 for the flow rate range F2 is y = b1 x 2 + b2 x + b3, and the correction formula f3 for the flow rate range F3 is y = c1 x 2 +c2·x+c3. The constants a1 to a3, b1 to b3, and c1 to c3 can be set appropriately.

[0031] Figure 6 shows an example of flow rate correction using correction formula f. Conventionally, the appropriate flow rate for an adult drip tube is set at 60 mL / h or more, while the appropriate flow rate for a pediatric drip tube is set at 60 mL / h or less. As shown in Figure 6, in this embodiment, the liquid volume can be measured with high accuracy over a wide flow rate range, for example, with an apparent flow rate (measured flow rate, pre-correction flow rate) of 0 to 5000 mL / h and an actual flow rate (corrected flow rate) of 0 to 600 mL / h.

[0032] As shown in Figure 6, the relationship between the apparent flow rate and the actual flow rate varies depending on the range of the apparent flow rate. Therefore, the range of the apparent flow rate is divided into three flow rate range sections F1, F2, and F3. Section F1 is for an apparent flow rate of 0 to 360 mL / h, section F2 is for an apparent flow rate of 360 to 1100 mL / h, and section F3 is for an apparent flow rate of 1100 to 5000 mL / h. To approximate the apparent flow rate to the actual measured amount, in section F1, the constants a1 to a3 of correction formula f1 can be, for example, -0.0008, 1.1294, and 0. In section F2, the constants b1 to b3 of correction formula f2 can be, for example, -0.0003, 0.6007, and 122.61. In section F3, the constants c1 to c3 of correction formula f3 can be, for example, -0.000004, 0.015290, and 426.78. Note that these numerical values ​​are merely examples and are not limited to these values. Different values ​​may result depending on the type of drip tube and the drug used. These values ​​may also vary depending on the number of flow rate sections.

[0033] Returning to FIG. 5 , the input variable of flow rate correction formula g is x and the output variable is y. The input variable x is the flow rate before correction, and the output variable y is the corrected volume (volume after correction). Correction formula g1 for flow rate range F1 can be expressed as y = number of drops × corrected volume per drop, in this case, the corrected volume is expressed as corrected volume = a4 · exp(a5 · x). Correction formula g2 for flow rate range F2 can be expressed as y = number of drops × corrected volume per drop, in this case, the corrected volume is expressed as corrected volume = b4 · exp(b5 · x). Correction formula g3 for flow rate range F3 can be expressed as y = number of drops × corrected volume per drop, in this case, the corrected volume is expressed as corrected volume = c4 · exp(c5 · x).

[0034] FIG. 7 shows an example of droplet volume change due to flow rate. In FIG. 7, the vertical axis represents the actual droplet volume (corrected volume), and the horizontal axis represents the apparent flow rate (measured flow rate, uncorrected flow rate). As shown in FIG. 7, the actual droplet volume decreases nonlinearly with the apparent flow rate. FIG. 7 also illustrates the ideal volume per droplet. As the apparent flow rate increases, the droplet volume gradually decreases compared to the ideal volume. To approximate the apparent flow rate to the measured volume, in section F1, the corrected volume constants a4 and a5 in correction formula g1 can be set to, for example, 19.7118 and 0.0008. In section F2, the corrected volume constants b4 and b5 in correction formula g2 can be set to, for example, 20.5410 and 0.0009. In section F3, the corrected volume constants c4 and c5 in correction formula g3 can be set to, for example, 12.6169 and 0.0005. These values ​​are merely examples and are not intended to be limiting, and may vary depending on the type of drip tube and the medication used. These values ​​may also vary depending on the number of flow rate categories.

[0035] As described above, the control unit 51 calculates the flow rate of the liquid based on the number of drops detected by the detection unit 53, selects a correction formula from multiple correction formulas (correction units) corresponding to the calculated flow rate, and calculates the corrected flow rate or corrected volume of the liquid using the selected correction formula. This allows the liquid volume to be measured with high accuracy over a wide flow rate range regardless of the appropriate flow rate range for each drip tube. Note that the flow rate correction formula f and flow rate correction formula g may be selected in advance depending on whether the corrected flow rate or corrected volume is to be calculated. Alternatively, a correction formula may be selected from both flow rate correction formula f and flow rate correction formula g, and both the corrected flow rate and corrected volume may be displayed on the corrected flow rate and correction display unit 54.

[0036] 4, multiple correction formulas are stored in association with multiple flow rate range segments, and the control unit 51 can select a correction formula corresponding to the flow rate range segment that includes the calculated flow rate. This makes it possible to correct the flow rate and integrated amount over a wide flow rate range that connects the flow rate range segments. Furthermore, because an appropriate correction formula can be selected for each flow rate range segment, it is possible to calculate the flow rate and integrated amount with high accuracy over a wide flow rate range.

[0037] The correction unit 61 includes a correction formula that converts the calculated flow rate into a corrected flow rate. The control unit 51 can calculate the corrected flow rate based on the calculated flow rate using the correction formula corresponding to the flow rate range segment. This makes it possible to correct the flow rate over a wide flow rate range formed by connecting the flow rate range segments. In addition, because an appropriate correction formula can be selected for each flow rate range segment, it is possible to calculate the flow rate and integrated amount with high accuracy over a wide flow rate range.

[0038] The correction unit 61 includes a conversion formula for converting the flow rate into a volume per droplet. The control unit 51 calculates a corrected volume by correcting the volume per droplet for the calculated flow rate using the conversion formula corresponding to the flow rate range segment, and can calculate the corrected flow rate based on the detected number of drops and the corrected volume. This makes it possible to calculate an appropriate droplet volume according to the flow rate even when the flow rate changes, and therefore to correct the flow rate over a wide flow rate range connecting flow rate range segments.

[0039] The correction unit 61 includes a conversion formula for converting the flow rate into a volume per droplet. The control unit 51 calculates a corrected volume by correcting the volume per droplet for the calculated flow rate using the conversion formula corresponding to the flow rate range category, and calculates the current corrected integrated amount by adding the corrected flow rate calculated based on the number of drops and the corrected volume detected during the update time from the previous time to the current time (second time point) to the previous corrected integrated amount (first time point). This makes it possible to determine an appropriate integrated amount even if the droplet volume per droplet differs from the ideal volume depending on the flow rate.

[0040] In addition, a flow rate range category is stored in association with each type of drip tube or drug used. The control unit 51 can accept the selection of the type of drip tube or drug used and select a flow rate range category corresponding to the selected type of drip tube or drug used. This makes it possible to apply a correction formula corresponding to the type of drip tube or drug used, and to determine the appropriate flow rate and cumulative amount regardless of the type of drip tube or drug used.

[0041] 8 is a diagram showing an example of the processing procedure for flow rate correction by the liquid volume measurement device of this embodiment. The control unit 51 accepts the selection of the type of drip tube and the medication to be used (S11) and selects a flow rate range category according to the accepted selection (S12). For the selection of the flow rate range category, see FIG. 4. The control unit 51 determines whether the start button has been operated (S13), and if no operation has been performed (NO in S13), continues the processing of step S13.

[0042] If the start button is operated (YES in S13), the control unit 51 acquires the number of drops in a predetermined time (S14) and calculates the pre-correction flow rate (S15). The pre-correction flow rate can be calculated as follows: Pre-correction flow rate = {number of drops in a predetermined time x ideal volume of one drop / predetermined time}. The predetermined time can be set appropriately.

[0043] The control unit 51 selects a correction formula (correction unit) corresponding to the flow rate range segment that includes the pre-correction flow rate (S16). For example, if the pre-correction flow rate is included in flow rate range F1, either flow rate correction formula f1 or g1 can be selected. Similarly, if the pre-correction flow rate is included in flow rate range F2, either flow rate correction formula f2 or g2 can be selected, and if the pre-correction flow rate is included in flow rate range F3, either flow rate correction formula f3 or g3 can be selected.

[0044] The control unit 51 calculates the corrected flow rate (corrects the flow rate) using the selected correction formula (S17) and displays the calculated corrected flow rate on the display unit 54 (S18). The control unit 51 determines whether the stop button has been operated (S19), and if the stop button has not been operated (NO in S19), continues the processing from step S14 onwards. If the stop button has been operated (YES in S19), the control unit 51 stops operation (S20) and ends the processing.

[0045] In the process shown in FIG. 8, when calculating the pre-correction flow rate at each predetermined time, the control unit 51 can determine the flow rate range and select a correction formula according to the flow rate range.

[0046] 9 is a diagram showing an example of the processing procedure for correcting the accumulated amount by the fluid volume measuring device of this embodiment. The control unit 51 accepts the selection of the type of drip tube and the medication to be used (S31) and selects a flow rate range category according to the accepted selection (S32). For the selection of the flow rate range category, see FIG. 4. The control unit 51 determines whether the start button has been operated (S33), and if no operation has been performed (NO in S33), continues the processing of step S33.

[0047] If the start button is operated (YES in S33), the control unit 51 acquires the number of drops per update time (S34) and calculates the pre-correction flow rate (S35). The pre-correction flow rate can be calculated as follows: pre-correction flow rate = {number of drops per update time x ideal volume of one drop / update time}. The update time can be set appropriately.

[0048] The control unit 51 selects a correction formula (correction unit) corresponding to the flow rate range segment that includes the pre-correction flow rate (S36). For example, if the pre-correction flow rate is included in flow rate range F1, flow rate correction formula g1 can be selected. Similarly, if the pre-correction flow rate is included in flow rate range F2, flow rate correction formula g2 can be selected, and if the pre-correction flow rate is included in flow rate range F3, flow rate correction formula g3 can be selected.

[0049] The control unit 51 calculates the corrected volume using the selected correction formula (S37). See FIG. 5 for the formula for calculating the corrected volume. The control unit 51 calculates the current corrected integrated amount based on the previous corrected integrated amount, the number of drops per update time, and the corrected volume (S38). The current corrected integrated amount can be calculated by {current corrected integrated amount = previous integrated amount + number of drops per update time × corrected volume per drop}.

[0050] The control unit 51 displays the calculated cumulative correction amount on the display unit 54 (S39). The control unit 51 determines whether the stop button has been operated (S40), and if the stop button has not been operated (NO in S40), the control unit 51 continues the processing from step S34 onwards. If the stop button has been operated (YES in S40), the control unit 51 stops operation (S41) and ends the processing.

[0051] In the process shown in FIG. 9, when calculating the pre-correction flow rate at each update time, the control unit 51 can determine the flow rate range and select a correction formula according to the flow rate range.

[0052] FIG. 10 is a diagram showing an example of an infusion flow rate measurement system according to this embodiment. The infusion flow rate measurement system includes a fluid volume measurement device. In this case, the fluid volume measurement device can be used as an infusion flow rate sensor. As shown in FIG. 10, the fluid volume measurement device includes a cylindrical container body having a transparent, cylindrical dripping portion 10. One end of a tube 21 through which the infusion flows is connected to the top of the container body, and the other end of the tube 21 is connected to a required infusion bag. The bottom of the container body has a reservoir portion for temporarily storing the infusion, and the infusion temporarily stored in the reservoir portion flows through a tube 22 and is injected into a patient's vein via an indwelling needle.

[0053] By including the fluid volume measuring device of this embodiment, the infusion flow measurement system can correct the flow rate using a correction formula according to the type of fluid, such as a nutrient or medicinal solution, and the type of drip tube. This improves the accuracy of flow rate measurement and allows the infusion flow measurement system to be used over a wide range of flow rates, regardless of the appropriate flow rate ranges for adult and pediatric drip tubes.

[0054] Figure 11 is a diagram showing an example of a urine flow measurement system according to this embodiment. The urine flow measurement system includes a fluid volume measurement device and a urinary drainage management device 100. In this case, the fluid volume measurement device can be used as a urine flow sensor. As shown in Figure 11, the fluid volume measurement device includes a cylindrical container body having a transparent, cylindrical dripping portion 10. The bottom of the container body is connected to a urine bag. One end of a tube is connected to the top of the container body, and the other end of the tube is connected to an indwelling bladder catheter equipped with a fluorescent oxygen partial pressure sensor and a temperature sensor, which extracts urine from the patient's body and drains it into the urine bag.

[0055] FIG. 12 shows an example of the configuration of a urinary catheterization management device 100. The urinary catheterization management device 100 starts operation when a start button 113 is operated and stops operation when a stop button 114 is operated. The urinary catheterization management device 100 has a measurement unit composed of a light-transmitting substrate disposed at the tip of a fluorescent oxygen partial pressure sensor provided at the tip of a catheter and a fluorescent material coated over substantially the entire surface of one side of the substrate. An excitation light is irradiated from a light-emitting unit 131 onto the fluorescent material. The fluorescent material absorbs the energy of the excitation light and becomes excited, emitting fluorescence when returning from the excited state to its original stable state (ground state). When oxygen is present in urine, the fluorescent characteristic quantity (fluorescence intensity or phase) changes due to quenching. This change in the fluorescent characteristic in response to oxygen concentration can be measured and converted into oxygen concentration or partial pressure.

[0056] The storage unit 101 stores acquired values ​​from all sensors such as the fluorescent oxygen partial pressure sensor and the temperature sensor, calculation results, values ​​during calculation, required parameter values, and the like.

[0057] The oxygen partial pressure calculation unit 102 converts a value acquired by a fluorescent oxygen partial pressure sensor that reacts to oxygen that comes into contact with the urinary tract into pO2 (oxygen partial pressure).

[0058] The temperature calculation unit 103 converts the value acquired by the temperature sensor in the flow path into a temperature.

[0059] The conductivity calculation unit 104 calculates the electrical properties (conductivity or resistivity) of urine from the values ​​acquired by the electrodes 134 in the flow path.

[0060] The urine volume calculation unit (correction) 105 has a function of calculating (correcting) the integrated volume of the flow sensor (liquid volume measuring device), and calculates and corrects the integrated volume of urine in the flow path.

[0061] The flow rate calculation unit (correction) 106 has a function of calculating (correcting) the flow rate of the flow sensor (liquid volume measurement device), and calculates and corrects the instantaneous value of the flow rate of urine in the flow path.

[0062] The oxygen excretion calculation unit 107 calculates the oxygen excretion amount from the calculated oxygen partial pressure and urine flow rate.

[0063] The urine volume condition setting unit 108 sets a threshold value for disease risk based on information about the patient (patient information) and the like.

[0064] The pO2-based AKI risk assessment unit 109 determines whether the calculated urinary pO2 exceeds the AKI risk threshold. The AKI risk is the risk of acute kidney injury. The pO2-based AKI risk assessment unit 109 can continuously monitor hypoxia of renal tissue, thereby enabling AKI risk to be detected in real time.

[0065] The oxygen excretion-based AKI risk assessment unit 110 determines whether the calculated oxygen excretion exceeds the AKI risk threshold.

[0066] The hourly urine volume-based disease risk assessment unit 111 determines whether the calculated hourly urine volume exceeds a disease risk threshold. The hourly urine volume-based disease risk assessment unit 111 can continuously monitor the hourly urine volume, and therefore can detect the risk of diseases diagnosed based on the hourly urine volume, such as AKI and diabetes insipidus, in real time.

[0067] The display control unit 112 displays the calculated values, the determination results, and the like on the monitor 120 .

[0068] 13 is a diagram showing an example of the processing procedure of the urinary drainage management device 100. The urinary drainage management device 100 accepts an operation to select the type of drip tube and urine as the liquid (S51), and performs calibration of sensors such as the fluorescent oxygen partial pressure sensor and temperature sensor (S52). The urinary drainage management device 100 determines whether or not the start button 113 has been operated (S53), and if the start button 113 has not been operated (NO in S53), continues the processing of step S53.

[0069] If the start button 113 has been operated (YES in S53), the urinary catheterization management device 100 acquires data from the fluorescent oxygen partial pressure sensor, temperature sensor, flow rate sensor, etc. (S54), and calculates the oxygen partial pressure, temperature, urine volume, and urine conductivity based on the acquired data (S55). The urinary catheterization management device 100 determines the AKI risk based on pO2 (S56), determines the AKI risk based on oxygen excretion (S57), and determines the disease risk based on the hourly urine volume (S58). Note that the order of the processing procedures from S56 to S58 is not limited.

[0070] The urinary catheterization management device 100 displays various information (calculated values, determination results, etc.) on the monitor 120 (S59), and determines whether the stop button 114 has been operated (S60). If the stop button 114 has not been operated (NO in S60), the urinary catheterization management device 100 continues processing from step S54 onwards. If the stop button has been operated (YES in S60), the urinary catheterization management device 100 stops operation (S61) and ends processing.

[0071] As described above, according to this embodiment, the urine flow rate can be corrected using a correction formula that corresponds to the type of drip tube and the type of liquid (urine). This allows for highly accurate flow rate measurement regardless of the appropriate flow rate range for the type of drip tube and the type of liquid (urine). In other words, although the appropriate flow rate ranges for adult and pediatric drip tubes are predetermined, highly accurate flow rate measurement can be achieved over a relatively wide flow rate range that is not dependent on this appropriate flow rate range. Furthermore, measuring urine flow rate allows for quick treatment of patients at risk of renal dysfunction.

[0072] REFERENCE SIGNS LIST 10 dripping part 11 cap part 21, 22 tube 30 liquid 40 measuring unit 41 light emitting part 42 light receiving part 50 control unit 51 control part 52 communication part 53 detection part 54 display part 55 operation part 56 time measuring part 57 memory 58 storage part 60 computer program 61 correction part 100 urinary catheterization management device

Claims

1. A liquid volume measuring device comprising a control unit and a detection unit that detects the number of drops of liquid droplets in a drip chamber, wherein the control unit calculates the flow rate of the liquid based on the number of drops detected by the detection unit, selects a correction unit corresponding to the calculated flow rate from among a plurality of correction units, and calculates a corrected flow rate or a corrected integrated amount of the liquid using the selected correction unit.

2. The liquid volume measuring device according to claim 1, wherein the plurality of correction units are associated with respective plurality of flow rate range sections, and the control unit selects a correction unit corresponding to the flow rate range section in which the calculated flow rate is included.

3. The liquid volume measuring device according to claim 2, wherein the correction unit includes a correction formula for converting the calculated flow rate into a corrected flow rate, and the control unit calculates a corrected flow rate based on the calculated flow rate using the correction formula corresponding to the flow rate range section in which the calculated flow rate is included.

4. The liquid volume measuring device according to claim 2, wherein the correction unit includes a conversion formula for converting the calculated flow rate into a volume per drop, and the control unit calculates a corrected volume obtained by correcting the volume per drop for the calculated flow rate using the conversion formula corresponding to the flow rate range section, and calculates a corrected flow rate based on the detected number of drops and the corrected volume.

5. The liquid volume measuring device according to claim 2, wherein the correction unit includes a conversion formula for converting the calculated flow rate into a volume per drop, and the control unit calculates a corrected volume obtained by correcting the volume per drop for the calculated flow rate using the conversion formula corresponding to the flow rate range section in which the calculated flow rate is included, and calculates the corrected integrated amount at the second time point by adding the corrected flow rate calculated based on the number of drops detected during the update time from the first time point to the second time point and the corrected volume to the corrected integrated amount at the first time point.

6. The liquid volume measuring device according to any one of claims 2 to 5, wherein the plurality of flow rate range sections are associated with each type of drip chamber or each type of drug used, and the control unit receives a selection of a type of drip chamber or a drug used, and selects a flow rate range section corresponding to the selected type of drip chamber or drug used.

7. The liquid volume measuring device according to any one of claims 1 to 5, wherein the control unit selects the correction unit each time the corrected flow rate or the corrected integrated amount is calculated.

8. An infusion flow rate measurement system comprising the liquid volume measurement device according to any one of claims 1 to 5.

9. A urine flow rate measurement system comprising the liquid volume measurement device according to any one of claims 1 to 5.

10. A computer program causing a computer to execute a process of calculating a flow rate of a liquid based on the number of drops detected by a detection unit that detects the number of drops of liquid droplets in a drip chamber, selecting a correction formula corresponding to the calculated flow rate from a plurality of correction formulas, and calculating a corrected flow rate or a corrected integrated amount of the liquid using the selected correction formula.

11. A liquid volume measurement method of calculating a flow rate of a liquid based on the number of drops detected by a detection unit that detects the number of drops of liquid droplets in a drip chamber, selecting a correction unit corresponding to the calculated flow rate from a plurality of correction units, and calculating a corrected flow rate or a corrected integrated amount of the liquid using the selected correction unit.

12. An infusion flow rate measurement method using the liquid volume measurement method according to claim 11.

13. A urine flow rate measurement method using the liquid volume measurement method according to claim 11.

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