Blood characteristic measurement device, dialysis system, and measurement program

Abstract

To provide a technique capable of measuring more types of blood characteristics with less measurement devices.SOLUTION: A measurement device 100 includes an optical sensor. The optical sensor detects optical characteristics of a fluid passing through the inside of a tube 500. The measurement device 100 uses detection output of the optical sensor and executes estimation of a hematocrit value of blood, estimation of a flow rate of blood, estimation of oxygen saturation of blood, and air bubble detection, with respect to the fluid in the tube 500.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to measuring blood characteristics of a patient, and more particularly, to measuring multiple types of blood characteristics of a patient. [Background technology]

[0002] Various proposals have been made in the past regarding the measurement of blood characteristics. For example, Japanese Patent Laid-Open Publication No. 11-104114 (Patent Document 1) discloses a technique in which a reflector is provided in a blood flow path, light is applied to the reflector, the amount of light reflected from the reflector is measured, and the amount of light is used to specify the hematocrit value and oxygen saturation level. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-104114 Summary of the Invention [Problem to be solved by the invention]

[0004] Obtaining more types of information on a patient's blood characteristics is useful for understanding the patient's condition more accurately. Conventionally, however, in order to obtain more types of information, more types of measuring devices are required, which results in high costs for medical facilities. In addition, an increase in the number of measuring devices increases the number of devices that medical personnel must operate, which places a heavy burden on medical personnel.

[0005] The present disclosure has been made in view of the above circumstances, and has an object to provide a technique that enables measurement of more types of blood characteristics with fewer measurement devices. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a blood characteristic measuring device including an optical sensor that detects optical information in a flow path of a patient's blood, and a controller that uses the detection output of the optical sensor to estimate a hematocrit value, a flow rate, and an oxygen saturation level of the patient's blood, as well as detect air bubbles in the blood flow path.

[0007] According to another aspect of the present disclosure, there is provided a dialysis system comprising a blood purifier, a blood circuit through which a patient's blood is circulated, the blood circuit including a blood inlet and a blood outlet of the blood purifier, a dialysate circuit through which a dialysate is circulated, the dialysate circuit including a dialysate inlet and a dialysate outlet of the blood purifier, a blood pump provided on the blood circuit, an optical sensor that detects optical information in the patient's blood circuit, and a controller that uses the detection output of the optical sensor to estimate the hematocrit value, blood flow rate, and blood oxygen saturation of the patient's blood, as well as detect air bubbles in the blood flow path.

[0008] In accordance with yet another aspect of the present disclosure, there is provided a measurement program that, when executed by one or more processors of a computer, causes the computer to perform the steps of obtaining detection output of an optical sensor in a patient's blood flow path, and using the detection output to estimate a hematocrit value, a blood flow rate, and an oxygen saturation level of the patient's blood, as well as detecting air bubbles in the blood flow path. Effect of the Invention

[0009] According to the present disclosure, techniques are provided that enable a greater variety of blood characteristics to be measured with fewer measurement devices. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of an example of a dialysis system including a first embodiment of a blood characteristic measuring device. [Diagram 2] FIG. 1 is a diagram showing the external appearance of a measuring device 100. [Diagram 3] 3 is a diagram showing the measuring device 100 in FIG. 2 with a door 152 open. [Figure 4] 1 is a diagram showing a state in which a tube 500 is attached to recesses 151A and 151B of the measuring device 100. FIG. [Diagram 5] FIG. 2 is a perspective view of a sensor unit 111. [Figure 6] FIG. 2 is a hardware block diagram of the sensor unit 111. [Figure 7] 13 is a diagram showing an example of a change in luminance in a captured image of a tube 500 in association with a change in a set value for liquid transfer. FIG. [Figure 8] 13 is a diagram showing an example of differences in luminance based on differences in hematocrit values ​​of blood in a captured image of a tube 500. FIG. [Figure 9] 11A and 11B are diagrams showing an example of differences in the relationship between a flow rate conversion value using the brightness of a captured image and a blood flow rate value based on differences in blood hematocrit values. [Figure 10] 1A and 1B are diagrams for explaining the influence of air bubbles generated in blood on an image captured by a sensor 102. [Figure 11] 1 is a diagram for explaining a change in luminance detected by the sensor 102 due to the generation of air bubbles in blood. [Figure 12] 11 is a diagram for explaining the influence of air bubbles generated in a fluid other than blood on an image captured by the sensor 102. FIG. [Figure 13] 1 is a diagram for explaining a change in luminance detected by the sensor 102 due to the generation of bubbles in a fluid other than blood. [Figure 14] 2 is a flowchart of a process executed in the measurement device 100. [Figure 15] FIG. 2 is a diagram showing an example of a display screen on a display 104. [Figure 16] FIG. 1 is a diagram showing the external appearance of a dialysis system 1A according to a second embodiment. [Figure 17] FIG. 2 is a diagram illustrating an example of a hardware configuration of a dialysis system 1A. [Figure 18]FIG. 11 is a diagram showing the configuration of a dialysis system 1 in a third embodiment. [Figure 19] FIG. 19 is a diagram illustrating a hardware configuration of a computer 200 in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of a dialysis system will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, the description thereof will not be repeated.

[0012] <First embodiment> [Dialysis system] Fig. 1 is a diagram showing the configuration of an example of a dialysis system including a first embodiment of a blood characteristic measuring device. The configuration of the dialysis system will be described with reference to Fig. 1. The dialysis system in Fig. 1 performs dialysis by a so-called online HDF (Hemodiafiltration) method. In this specification, online HDF is merely one example of a dialysis method, and the term dialysis system is intended to include any method of performing dialysis.

[0013] The dialysis system 1 includes a dialysis unit 3 having a fluid supply / removal device 2 and a hemodialyzer 30. The dialysis system 1 further includes a measurement device 100 for measuring characteristics of blood circulated in the dialysis unit 3. The measurement device 100 estimates the hematocrit value, flow rate, and oxygen saturation of the patient's blood, and also performs air bubble detection in the tubes through which the blood is circulated.

[0014] The hemodialyzer 30 includes a semipermeable membrane made of, for example, a hollow fiber membrane. The dialysis unit 3 also includes a blood circuit BC having an upstream blood line BC1 and a downstream blood line BC2, a dialysate circuit DC having an upstream dialysate line DC1 and a downstream dialysate line DC2, and a replacement fluid circuit SC.

[0015] One end of an upstream blood line BC1 is connected to a blood inlet BF1 of the hemodialysis machine 30. The other end of the upstream blood line BC1 is provided with an arterial puncture needle 31. The arterial puncture needle 31 is inserted into the arteriovenous shunt of the patient P1 (the portion of the arteriovenous shunt downstream of the blood flow during non-dialysis).

[0016] One end of a downstream blood line BC2 is connected to the blood outlet BF2 of the hemodialysis machine 30. The other end of the downstream blood line BC2 is provided with a venous puncture needle 32. The venous puncture needle 32 is inserted into a vein of a patient P1.

[0017] The blood circuit BC is provided with a blood pump 23 for pumping blood, an arterial drip chamber 41, and a venous drip chamber 42. In the blood circuit BC, the blood of the patient P1 is introduced from the artery to the hemodialyzer 30 via the arterial drip chamber 41 by the blood pump 23, and then returned to the vein via the venous drip chamber 42. The arterial drip chamber 41 and the venous drip chamber 42 are each provided with an upstream pressure measuring device 21 and a downstream pressure measuring device 22 for measuring the pressure of the blood taken from the patient P1 and on the blood circuit BC.

[0018] One end of an upstream dialysate line DC1 is connected to a dialysate inlet DF1 of the hemodialyzer 30. The other end of the upstream dialysate line DC1 is connected to the supply liquid water removal device 2. When the dialysate pump 24 is driven, fresh dialysate is introduced from the supply liquid water removal device 2 to the dialysate inlet DF1.

[0019] One end of a downstream dialysate line DC2 is connected to the dialysate outlet DF2 of the hemodialyzer 30. The other end of the downstream dialysate line DC2 is connected to the supply liquid water removal device 2. When the dialysate pump 24 is driven, the used dialysate is discharged from the dialysate outlet DF2 to the supply liquid water removal device 2.

[0020] The fluid supply / removal device 2 supplies (injects) fresh dialysis fluid through the fluid replacement circuit SC to the arterial drip chamber 41. As a result, in the arterial drip chamber 41, fresh dialysis fluid, which is an example of a replacement fluid, is supplied to the blood of the patient P1.

[0021] The fluid supply / removal device 2 includes a dialysis fluid pump 24. A fluid replacement pump 25 for sending the dialysis fluid from the fluid supply / removal device 2 to the arterial drip chamber 41 is provided on the fluid replacement circuit SC.

[0022] A measuring device 100 is incorporated on the upstream blood line BC1 in the dialysis unit 3. Blood on the upstream blood line BC1 is introduced into the measuring device 100, then discharged from the measuring device 100 and returned to the upstream blood line BC1.

[0023] [Measuring equipment] Fig. 2 is a diagram showing the external appearance of the measurement device 100. As shown in Fig. 2, the measurement device 100 includes a main body 151 and a door 152. The door 152 is provided with an operation unit 103 and a display 104. Fig. 3 is a diagram showing the measurement device 100 of Fig. 2 with the door 152 open.

[0024] 2 and 3, a sensor unit 111 is incorporated in a main body 151. Recesses 151A and 151B are formed in the upper and lower parts of the main body 151, respectively. Fig. 4 is a diagram showing a state in which a tube 500 is attached to recesses 151A and 151B of the measuring device 100. The sensor unit 111 detects optical characteristics of a fluid passing through the tube 500.

[0025] 5 is a perspective view of the sensor unit 111. An aperture member 120 is provided in the center of the sensor unit 111. Eight LEDs (light-emitting diodes) are provided on the outer side of the aperture member 120. An optical sensor (sensor 102, which will be described later with reference to FIG. 6) is provided behind the aperture member 120.

[0026] 6 is a hardware block diagram of the sensor unit 111. As shown in FIG. 6, the sensor unit 111 further includes a controller 110 that controls the operation of the sensor unit 111, in addition to the LED 101, the sensor 102, the operation unit 103, and the display 104.

[0027] The controller 110 may be configured with one or more processors and a memory. The functions of the controller 110 may be realized by one or more processors executing a given program. The controller 110 may also be realized by an integrated circuit such as a field-programmable gate array (FPGA) and / or an application specific integrated circuit (ASIC).

[0028] The controller 110 receives information input by operating the operation unit 103 , and also displays various types of information on the display 104 .

[0029] The sensor 102 is realized by, for example, a complementary metal oxide semiconductor (CMOS) and / or a charge coupled device (CCD). In the measurement device 100, an LED 101 is used as a light source. The sensor 102 detects the luminance and chromaticity (x value, y value) of each of R (red), G (green), and B (blue) from an image of the tube 500. In the measurement device 100, the characteristics of the fluid (blood, dialysis fluid, etc.) in the tube 500 are identified based on these detection results.

[0030] The measurement device 100 further includes a communication interface (I / F) 105 for the controller 110 to communicate with an external device. The communication I / F 105 is realized, for example, by a wireless transceiver. The controller 110 can transmit the detection result of the sensor 102 and / or the determined characteristics of the fluid in the tube 500 to the external device.

[0031] [Hematocrit Estimation] In the measurement device 100, the memory of the controller 110 stores information that specifies a regression equation for determining the hematocrit value of the blood in the tube 500. The regression equation relates the luminance detected by the sensor 102 to the hematocrit value of the blood in the tube 500.

[0032] In one implementation, the regression equation is identified by multivariate analysis using multiple variables (including brightness and hematocrit) that have been identified for blood with known hematocrit values.

[0033] One example of the regression equation expresses the hematocrit estimate as a linear expression of the luminance detected by the sensor 102. Another example expresses the hematocrit estimate as a linear expression of the luminance detected by the sensor 102 and the set value of the flow rate of the blood pump 23.

[0034] Yet another example expresses the hematocrit estimate as a linear expression of the luminance and chromaticity of a particular color detected by sensor 102, as expressed as the following equation (1): In equation (1), Vht represents the hematocrit estimate, Vbg represents the luminance of green detected by sensor 102, Vcy represents the y value of chromaticity detected by sensor 102, and a, b, and c represent constants.

[0035] Vht = ab Vbg-c Vcy … (1) The regression equation may relate the ratio of the luminance of at least two of the three colors detected by the sensor 102 to the hematocrit value.

[0036] [Blood flow estimation] In the measurement device 100, the memory of the controller 110 stores information specifying a regression equation for calculating the flow rate (per unit time) of blood in the tube 500. The regression equation correlates the luminance detected by the sensor 102 with the flow rate of blood in the tube 500. The regression equation may be set for each hematocrit value of blood. The regression equation for calculating the flow rate will be described below.

[0037] Fig. 7 is a diagram showing an example of a change in brightness in a captured image of the tube 500 with a change in the set value of the liquid transfer. Fig. 7 shows two images 71 and 72 of blood captured in the tube 500. Image 71 is an image with the highest overall brightness when the set value of the flow rate of the blood pump 23 is 50 mL / min. Image 72 is an image with the highest overall brightness when the set value is 100 mL / min. As can be seen from Fig. 7, when the flow rate of blood in the tube 500 changes, a difference occurs in the images captured by the sensor 102.

[0038] FIG. 8 is a diagram showing an example of differences in brightness based on differences in hematocrit values ​​of blood in a captured image of a tube 500. In the graph of FIG. 8, the horizontal axis represents the number of frames in the sensor 102, which essentially represents time. The vertical axis represents the average value of the gradation value representing brightness for each frame, based on the luminance of three colors (R, G, B) detected by the sensor 102. The gradation values ​​shown in FIG. 8 represent values ​​in the range of 0 to 255. In one implementation example, the sensor 102 generates a detection output every 1 / 30 seconds. In this case, the detection output of a certain frame represents the detection output 1 / 30 seconds after the detection output of the immediately preceding frame.

[0039] In Fig. 8, line L11 represents the results for blood with a hematocrit value of 26. Line L12 represents the results for blood with a hematocrit value of 38. As can be seen from Fig. 8, the higher the hematocrit value of the blood in tube 500, the smaller the average brightness.

[0040] Fig. 9 is a diagram showing an example of the difference in the relationship between the flow rate conversion value using the brightness of a captured image and the blood flow rate value based on the difference in the hematocrit value of blood. The horizontal axis of the graph in Fig. 9 represents the flow rate conversion value. The flow rate conversion value means the average value of the brightness of three colors (R, G, B) of the sensor 102 for a certain period of time (e.g., 200 frames). The vertical axis represents the measurement result of the blood flow rate (blood flow rate value) measured by a measuring device (e.g., a blood flow meter) other than the sensor 102.

[0041] 9, each triangular plot represents the flow rate equivalent value and measurement result for blood with a hematocrit value of 26. Each circular plot represents the flow rate equivalent value and measurement result for blood with a hematocrit value of 38. Line L21 represents the approximation curve for the hematocrit value of 26, and line L22 represents the approximation curve for the hematocrit value of 38.

[0042] As shown by lines L21 and L22 in the graph of FIG. 9, a regression equation relating the flow rate equivalent value to the measurement result can be set for each blood hematocrit value.

[0043] From the above, a regression equation that relates the flow rate conversion value to the flow rate for each hematocrit value is stored in the memory of the controller 110.

[0044] 9, the regression equation is shown as a quadratic curve. However, the method of expressing the regression equation is not limited to a quadratic curve.

[0045] Furthermore, the value associated with the flow rate in the regression equation does not have to be the average value of the luminance of the three colors (R, G, B), but may be the luminance value of one of the three colors, or the average value of the luminance values ​​of two colors.

[0046] [Oxygen saturation estimation] In the measurement device 100, the memory of the controller 110 stores information specifying a regression equation for determining the oxygen saturation of the blood in the tube 500. The regression equation relates the luminance detected by the sensor 102 to the oxygen saturation of the blood in the tube 500.

[0047] In one implementation, the regression equation is identified by multivariate analysis using multiple variables (including brightness and oxygen saturation) that have been identified for blood with known oxygen saturation.

[0048] An example of the regression equation expresses the estimated value of oxygen saturation as a linear equation of the luminance detected by the sensor 102. Any linear equation is possible as long as it has the luminance of at least one of the three colors as a variable. For example, the linear equation may have the luminance of at least one of the three colors as a variable, may have only the luminance of one of the three colors as a variable, or may have the average value of the luminance of two or more of the three colors as a variable.

[0049] A specific example of the linear expression is expressed as the following expression (2): In expression (2), Vos represents an estimated value of oxygen saturation, Vbg represents the luminance of green detected by the sensor 102, Vbb represents the luminance of blue detected by the sensor 102, and p, q, and r represent constants.

[0050] Vos = p + q Vbg - r Vbb … (2) The regression equation may relate the ratio of the luminance of at least two of the three colors detected by the sensor 102 to the oxygen saturation level.

[0051] [Air bubble detection] In the measuring device 100, the memory of the controller 110 stores information for detecting the occurrence of air bubbles in the tube 500. One example of the information for detecting the occurrence of air bubbles is a threshold value related to the luminance detected by the sensor 102. Another example is a threshold value related to a differential value of a change in luminance. The information for detecting the occurrence of air bubbles will be described below.

[0052] Fig. 10 is a diagram for explaining the effect of air bubbles in blood on an image captured by the sensor 102. Fig. 10 shows images 73 and 74 captured by the sensor 102. Image 73 corresponds to the state before air bubbles are generated in the blood. Image 74 corresponds to the state when air bubbles are generated in the blood. Image 74 is darker overall than image 73.

[0053] 11 is a diagram for explaining a change in luminance detected by the sensor 102 due to the generation of air bubbles in blood. In Fig. 11, the horizontal axis represents the number of frames in the sensor 102, and the vertical axis represents the average value (average luminance) of the luminance of three colors detected by the sensor 102.

[0054] 11, line L31 represents the change in average luminance. Px indicates the timing at which air bubbles occur in the blood in tube 500. In line L31, the value drops sharply at the timing indicated by Px.

[0055] 10 and 11, the occurrence of air bubbles in the blood in the tube 500 affects the detection output of the sensor 102. Based on this, in the measuring device 100, when the controller 110 determines that a change corresponding to the occurrence of air bubbles has occurred in the detection output of the sensor 102, it identifies the occurrence of air bubbles.

[0056] The controller 110 may determine the occurrence of an air bubble when the luminance detected by the sensor 102 (e.g., the average luminance of the three colors) drops in a first manner. One example of the first manner is when the luminance crosses a given threshold and changes below the threshold. Another example is when the luminance detected at a certain point in time changes below a value of a specific ratio with respect to the luminance detected immediately before (e.g., changes to a value less than 10% of the immediately before luminance). Yet another example is when the derivative value of the luminance changes below a given threshold (the derivative value becomes a large negative value).

[0057] The controller 110 is configured to be able to detect the generation of air bubbles not only when blood is circulating in the tube 500 but also when a fluid other than blood is circulating in the tube 500.

[0058] Fig. 12 is a diagram for explaining the influence of air bubbles generated in a fluid other than blood on an image captured by the sensor 102. Fig. 12 shows images 75 and 76 captured by the sensor 102. The images 75 and 76 are images captured when saline is circulating in the tube 500. The image 75 corresponds to a state before air bubbles are generated in the saline. The image 76 corresponds to a state when air bubbles are generated in the saline. Contrary to the example described with reference to Fig. 10, the image 75 before air bubbles are generated is generally darker than the image 76 when air bubbles are generated.

[0059] Fig. 13 is a diagram for explaining a change in luminance detected by the sensor 102 due to the generation of bubbles in a fluid other than blood. In Fig. 13, the horizontal axis represents the number of frames in the sensor 102, and the vertical axis represents the average value (average luminance) of the luminance of three colors detected by the sensor 102. Physiological saline is used as an example of a fluid other than blood.

[0060] 13, line L41 represents the change in average luminance. Px indicates the timing at which air bubbles are generated in the physiological saline in the tube 500. In line L41, the value temporarily rises significantly at the timing indicated by Px.

[0061] 12 and 13, the occurrence of air bubbles in a fluid other than blood in the tube 500 affects the detection output of the sensor 102. Based on this, in the measuring device 100, when the controller 110 determines that a change corresponding to the occurrence of air bubbles has occurred in the detection output of the sensor 102, it identifies the occurrence of air bubbles.

[0062] For example, assume that during priming, a tube for supplying physiological saline is connected between the arterial puncture needle 31 and the measurement device 100, and physiological saline is circulated in the blood circuit BC. In such a case, the controller 110 can identify the occurrence of air bubbles in the physiological saline in the tube 500.

[0063] The controller 110 may determine the occurrence of an air bubble when the luminance detected by the sensor 102 (e.g., the average luminance of the three colors) rises in a second manner. One example of the second manner is when the luminance crosses a given threshold and changes to exceed the threshold. Another example is when the luminance detected at a certain point in time changes to exceed a certain ratio value with respect to the luminance detected immediately before (e.g., the luminance changes to a value exceeding 200% with respect to the immediately before luminance). Yet another example is when the derivative value of the luminance changes to exceed a given threshold (the derivative value becomes a large positive value).

[0064] As described above, controller 110 determines the occurrence of air bubbles in the fluid in tube 500 in response to a change in the luminance detected by sensor 102 in a given manner. More specifically, when the fluid in tube 500 is blood, controller 110 determines the occurrence of air bubbles in response to a decrease in the luminance detected by sensor 102 in a first manner, and when the fluid in tube 500 is other than blood, controller 110 determines the occurrence of air bubbles in response to an increase in the luminance detected by sensor 102 in a second manner.

[0065] [Processing flow] Fig. 14 is a flowchart of a process executed in the measuring device 100. In one implementation example, the process is started in response to power being turned on to the controller 110 of the measuring device 100. In one implementation example, the process of Fig. 14 is performed in the measuring device 100 by one or more processors of the controller 110 executing a given program.

[0066] 14, in step S1, measuring instrument 100 determines whether or not the timing to start measurement has arrived.

[0067] The timing to start the measurement may be the timing when an instruction to start the measurement is input to the measuring device 100, or the timing when an instruction to start the measurement is received from an external device, or may be set in advance by a timer function. The instruction may be input as an operation to the operation unit 103.

[0068] The measuring device 100 repeats the control of step S1 until it determines that the timing to start measurement has arrived (NO in step S1), and when it determines that the timing has arrived (YES in step S1), it proceeds to control to step S2.

[0069] In step S2, the measuring device 100 stores the detection output of the sensor 102 for a certain period of time (for example, 200 frames) in a memory.

[0070] In step S3, the measuring device 100 reads out from the memory the detection output for the certain period of time that was stored in step S2.

[0071] In step S4, measuring device 100 calculates an estimate of the hematocrit value using the detection output read out in step S3. The calculation of the estimate of the hematocrit value of the blood in tube 500 follows, for example, the method described in [Estimation of Hematocrit Value] above.

[0072] In step S5, the measuring device 100 uses the detection output read out in step S3 to calculate an estimate of the blood flow rate in the tube 500. The calculation of the estimate of the blood flow rate in the tube 500 follows, for example, the method described in [Estimation of Blood Flow Rate] above.

[0073] In step S5, the estimated value of the hematocrit value calculated in step S4 may be used. More specifically, a plurality of regression equations for flow rate estimation may be stored in the memory of measurement device 100. Each of the plurality of regression equations corresponds to two or more hematocrit values. Measurement device 100 may select, from the plurality of regression equations, a regression equation corresponding to the hematocrit value calculated in step S4 (or input from outside), and use the selected regression equation to calculate an estimated value of the blood flow rate.

[0074] In step S6, the measuring device 100 uses the detection output read out in step S3 to calculate an estimate of the oxygen saturation of the blood in the tube 500. The calculation of the estimate of the oxygen saturation of the blood in the tube 500 follows, for example, the method described in [Estimation of oxygen saturation] above.

[0075] In step S7, the measuring device 100 uses the detection output read out in step S3 to check whether or not air bubbles have been generated in the tube 500. The check as to whether or not air bubbles have been generated follows the method described in [Air bubble detection] above.

[0076] The measuring device 100 may be notified of information indicating whether the fluid circulating in the tube 500 is blood or something other than blood. When the measuring device 100 is notified that the fluid circulating in the tube 500 is blood, the measuring device 100 detects the generation of air bubbles in the blood in step S7. On the other hand, when the measuring device 100 is notified that the fluid circulating in the tube 500 is something other than blood, the measuring device 100 detects the generation of air bubbles in the fluid other than blood in step S7. When neither of the notifications is received, the measuring device 100 may be configured to detect the generation of air bubbles in the blood in step S7. The above notification may be transmitted to the measuring device 100 from an external device, or may be input to the measuring device 100 as an operation on the operation unit 103.

[0077] In step S8, the measuring device 100 outputs the results of the calculations in steps S4 to S6 and the results of the checks in step S7. The output may be displayed on the display 104, or may be transmitted to an external device.

[0078] Fig. 15 is a diagram showing an example of a display screen on display 104. With reference to Fig. 15, an example of the display on display 104 in step S8 will be described.

[0079] 15 displays an example of an estimated hematocrit value of "31," an example of an estimated blood flow rate (per unit time) of "50 ml / min," and an example of an estimated oxygen saturation of "98%." Screen 80 further displays "none," indicating that the occurrence of air bubbles could not be identified.

[0080] Returning to FIG. 14, in step S9, the measuring device 100 determines whether or not it is time to end the measurement.

[0081] The timing to end the measurement may be when an instruction to end the measurement is input to the measuring device 100, or when an instruction to end the measurement is received from an external device, or may be set in advance by a timer function.

[0082] If the measuring device 100 determines that the time to end the measurement has not arrived (NO in step S9), it returns control to step S2, and if it determines that the time has arrived (YES in step S9), it ends the processing of FIG. 14.

[0083] 14, in the measuring device 100, the detection output from the sensor 102 at regular intervals is used to estimate the hematocrit value, the flow rate, and the oxygen saturation of the blood, and also to detect air bubbles in the tube 500. These operations are repeated until the timing to end the measurement arrives.

[0084] <Second embodiment> In the first embodiment, in the dialysis system 1, the measuring device 100 alone performs the estimation of the hematocrit value, the estimation of the flow rate, and the estimation of the oxygen saturation level, and also performs the detection of air bubbles in the tube 500. In the second embodiment, the dialysis system includes a configuration equivalent to the sensor unit 111 of the measuring device 100. Then, the dialysis system uses the detection output from the configuration to perform the estimation of the hematocrit value, the estimation of the flow rate, and the estimation of the oxygen saturation level, and also performs the detection of air bubbles in the tube 500.

[0085] [External appearance of dialysis system] 16 is a diagram showing the external appearance of a dialysis system 1A in the second embodiment. The dialysis system 1A is covered with a housing 1X, and a rack 2A is provided in the housing 1X. A sensor unit 100A is installed in the rack 2A.

[0086] [Hardware configuration of dialysis system] Fig. 17 is a diagram showing an example of a hardware configuration of the dialysis system 1A. The hardware configuration of the dialysis system 1A will be described with reference to Fig. 17.

[0087] The dialysis system 1A includes a controller 10 that controls the overall operation of the dialysis system 1A. The controller 10 may be realized by one or more processors and memories. The controller 10 may be realized by an integrated circuit such as an FPGA and / or an ASIC.

[0088] The dialysis system 1A further includes a storage device 11. The storage device 11 is realized by a recording medium such as a hard disk or a flash memory. The storage area of ​​the storage device 11 includes a program storage area 11A for storing a program executed by the processor of the controller 10, and a data storage area 11B for storing various data used in executing the program.

[0089] The dialysis system 1A further includes a communication I / F 12, an operation unit 13, and a display 14. The communication I / F 12 is used for communication between the dialysis system 1A and other devices, and is realized, for example, by a wireless transceiver. The operation unit 13 is provided so that the dialysis system 1 can receive operations from outside. The operation unit 13 is realized, for example, by an operation button and / or a touch panel. The display 14 displays various information according to instructions from the controller 10.

[0090] 1, the dialysis system 1A includes an upstream pressure measuring device 21, a downstream pressure measuring device 22, a blood pump 23, a dialysis fluid pump 24, and a replacement fluid pump 25. The controller 10 controls the operations of these components.

[0091] In the second embodiment, the controller 110 uses the detection output from the sensor 102 of the sensor unit 100A to perform the process of Fig. 14. As a result, the dialysis system 1A uses the detection output from the sensor 102 to estimate the hematocrit value, flow rate, and oxygen saturation of the patient's blood, and further performs air bubble detection in the tube through which the blood circulates.

[0092] <Third embodiment> [Dialysis system configuration] 18 is a diagram showing the configuration of a dialysis system 1 in the third embodiment. In the third embodiment, the measuring device 100 of the dialysis system 1 is configured to be able to communicate with a computer 200. The communication may be wired or wireless.

[0093] In the third embodiment, the measurement device 100 transmits the detection output of the sensor 102 to the computer 200. The computer 200 uses the detection output of the sensor 102 to estimate the hematocrit value, the flow rate, and the oxygen saturation of the patient's blood, and further performs air bubble detection in the tube 500.

[0094] [Computer Configuration] Fig. 19 is a diagram showing a hardware configuration of the computer 200 in Fig. 18. The hardware configuration of the computer 200 will be described with reference to Fig. 19.

[0095] Computer 200 is realized by, for example, a general-purpose computer. Computer 200 includes a CPU (Central Processing Unit) 211. CPU 211 realizes a given function by executing a program. The program may include not only a program that can be directly executed by CPU 211, but also a program in a source program format, a compressed program, an encrypted program, and the like.

[0096] The computer 200 includes a ROM (Read Only Memory) 212, an input I / F 213, a RAM (Random Access Memory) 214, a hard disk 215, a media drive 216, a communication I / F 217, and an output I / F 218. The components in the computer 200 are connected to each other via a bus.

[0097] The hard disk 215 stores programs and data used for executing the programs in a non-volatile manner.

[0098] The input I / F 213 is connected to a keyboard 221 and a mouse 222. A CD-ROM 219, a USB (Universal Serial Bus) memory, or other recording media may be attached to the media drive 216. The communication I / F 217 transmits and receives data to and from an external device (e.g., the measuring device 100) via a wired or wireless connection. The CPU 211 communicates with the external device via the communication I / F 217. The output I / F 218 is connected to a display 223. The CPU 211 controls the display of the display 223 via the output I / F 218.

[0099] [Measurement program] A measurement program is installed in computer 200. The measurement program, when executed by CPU 211, causes computer 200 to perform the hematocrit value estimation, flow rate estimation, and blood oxygen saturation estimation described with reference to Fig. 14, and further causes computer 200 to perform air bubble detection in tube 500 described with reference to Fig. 14.

[0100] Each embodiment disclosed herein should be considered as illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. In addition, the inventions described in the embodiments and each modified example are intended to be implemented, as far as possible, either alone or in combination. [Explanation of symbols]

[0101] 1,1A dialysis system, 1X housing, 2 fluid supply / removal device, 2A rack, 3 dialysis unit, 10,110 controller, 11 storage device, 13,103 operation unit, 14,104,223 display, 21 upstream pressure measuring device, 22 downstream pressure measuring device, 23 blood pump, 24 dialysis fluid pump, 25 replacement fluid pump, 30 hemodialysis machine, 31 arterial puncture needle, 32 venous puncture needle, 71-76 image, 80 screen, 100 measuring device, 100A,111 sensor unit, 102 sensor, 120 throttle member, 151 main body, 151A,151B recess, 152 door, 200 computer.

Claims

1. an optical sensor for detecting optical information in a patient's blood flow path; and a controller that uses the detection output of the optical sensor to estimate the hematocrit value, flow rate, and oxygen saturation of the patient's blood, as well as detect air bubbles in the blood flow path.

2. 2. The blood characteristic measuring device according to claim 1, wherein the controller calculates the hematocrit value of the patient by applying the brightness of at least one color detected by the optical sensor to a regression equation for the hematocrit value in estimating the hematocrit value.

3. The blood characteristic measuring device of claim 2 , wherein the at least one color includes green.

4. 4. The blood characteristic measuring device according to claim 2, wherein the controller, in estimating the hematocrit value, further calculates the hematocrit value of the patient by applying a y value of chromaticity detected by the optical sensor to the hematocrit value regression equation.

5. The controller, in estimating the flow rate, selecting one flow rate regression equation corresponding to the hematocrit value estimated in the estimation of the hematocrit value from the two or more flow rate regression equations; 2. The blood characteristic measuring device according to claim 1, wherein the blood flow rate of the patient is calculated by applying the luminance of at least one color of the detection output to the one flow rate regression equation.

6. The blood characteristic measuring device of claim 5 , wherein the luminance of the at least one color is an average luminance of red, blue, and green colors.

7. 3. The blood characteristic measuring device according to claim 1, wherein the controller calculates the oxygen saturation of the patient's blood by applying the brightness of the multiple colors detected by the optical sensor to a regression equation for oxygen saturation in estimating the oxygen saturation.

8. The blood characteristic measuring device according to claim 7 , wherein the plurality of colors include blue and green.

9. 3. The blood characteristic measuring device according to claim 1, wherein the controller, in the bubble detection, identifies the occurrence of bubbles in the blood flow path in response to a change in brightness detected by the optical sensor in a given manner.

10. The controller: When the patient's blood is flowing through the blood flow path, the occurrence of the air bubble is identified when the brightness detected by the optical sensor decreases in a first manner; 10. The blood characteristic measuring device according to claim 9, wherein when a fluid other than the patient's blood is flowing in the blood flow path, the occurrence of the air bubbles is identified when the brightness detected by the optical sensor increases in a second manner.

11. Blood purifier, A blood circuit through which the patient's blood is circulated, the blood circuit including a blood inlet and a blood outlet of the blood purifier; a dialysis fluid circuit in which a dialysis fluid is circulated, the dialysis fluid circuit including a dialysis fluid inlet and a dialysis fluid outlet of the blood purifier; a blood pump provided on the blood circuit; an optical sensor for detecting optical information in the patient's blood circuit; and a controller that uses the detection output of the optical sensor to estimate the hematocrit value, blood flow rate, and blood oxygen saturation of the patient's blood, as well as detect air bubbles in the blood circuit.

12. When executed by one or more processors of a computer, the computer is caused to: obtaining a detection output of an optical sensor in a flow path of the patient's blood; and using the detection output to perform steps of estimating the hematocrit value, blood flow rate, and blood oxygen saturation of the patient's blood, as well as detecting air bubbles in the blood flow path.

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