Dual channel air monitoring system for dialysis

Abstract

The application discloses a kind of double-channel air monitoring systems for dialysis related to blood purification technical field, comprising: air monitoring component, setting on intravenous line, including at least two sensing units for independent acquisition circuit signal;Monitoring component includes mutually independent main control processing unit and protection processing unit;Main control processing unit is electrically connected with the first sensing unit in air monitoring component;Protection processing unit is electrically connected with the second sensing unit in air monitoring component;Wherein, main control processing unit and protection processing unit respectively according to received circuit signal carry out bubble determination, and when main control processing unit and / or protection processing unit determine that there is bubble, pass through series control logic drive blocking component executed on intravenous line and carry out the operation of blocking intravenous line.The system can improve the reliability of system operation in the process of bubble detection, and enhance the security capability of dialysis process.

Description

Technical Field

[0001] This invention relates to the field of blood purification technology, and in particular to a dual-channel air monitoring system for dialysis. Background Technology

[0002] During hemodialysis treatment, the patient's blood is drawn through an extracorporeal circulation loop, undergoes substance exchange in the dialyzer, and is then returned to the body. The safety of the intravenous tubing is directly related to the patient's life. Air entering the circulatory system can cause gas embolism, which can seriously harm vital organs such as the heart and brain. Therefore, effective detection and timely handling of air bubbles in the intravenous tubing are critical safety aspects of dialysis equipment.

[0003] Dialysis equipment typically detects air bubbles in the circuit using air monitoring devices. Common methods include ultrasound-based bubble detection technology or indirect detection based on changes in liquid level and optical signals. However, these technologies often use a single detection channel for bubble identification. If the detection unit or signal processing link malfunctions during the detection process, the detection results may fail, reducing the overall system safety. Furthermore, in practical use, factors such as changes in the flow state of the venous tubing, tubing deformation, and signal drift can easily interfere with the detection signal, affecting the accuracy of bubble detection. Additionally, the system structure design of these detection schemes often features independently configured functional modules, increasing system complexity and installation and maintenance difficulties.

[0004] Therefore, under the relevant technological conditions, how to improve the reliability and security of system operation while ensuring detection accuracy remains an issue that needs further attention in this field. Summary of the Invention

[0005] This invention aims to at least partially address one of the technical problems in related technologies. Therefore, the object of this invention is to provide a dual-channel air monitoring system for dialysis to improve the reliability of bubble detection and the safety of the dialysis process.

[0006] To achieve the above objectives, a first aspect of the present invention provides a dual-channel air monitoring system for dialysis, comprising: An air monitoring component, installed on a vein line, includes at least two sensing units for independently acquiring loop signals; The monitoring component includes a main control processing unit and a protection processing unit that are independent of each other; the main control processing unit is electrically connected to a first sensing unit in the air monitoring component; the protection processing unit is electrically connected to a second sensing unit in the air monitoring component. The main control processing unit and the protection processing unit respectively determine the presence of bubbles based on the received loop signals. When the main control processing unit and / or the protection processing unit determine that a bubble exists, the blocking component set on the vein is driven to perform a vein blocking operation through serial control logic.

[0007] In addition, the system of the above embodiments of the present invention may also have the following additional technical features: According to one embodiment of the present invention, the main control processing unit and the protection processing unit respectively filter the received loop signal to obtain the current detection voltage value for bubble detection.

[0008] According to one embodiment of the present invention, the main control processing unit and the protection processing unit dynamically update the current reference value based on the current detection voltage value and the reference value at the previous moment, and perform bubble determination by using the current reference value and the current detection voltage value.

[0009] According to one embodiment of the present invention, when updating the reference value, a first difference between the current detection voltage value and the reference value at the previous moment is calculated, and the current detection voltage value corresponding to the first difference exceeding a preset abnormal threshold is discarded as an abnormal value.

[0010] According to one embodiment of the present invention, the bubble determination includes large bubble determination logic: Calculate the second difference between the current detected voltage value and the current reference value; When the second difference exceeds the preset large bubble alarm threshold, a large bubble alarm is triggered and the blocking component is activated.

[0011] According to one embodiment of the present invention, the bubble determination further includes small bubble determination logic: Within a preset sliding time window, the second difference between the current detection voltage value and the current reference value of a single detection point is continuously monitored. When the second difference is within the preset small bubble amplitude range, it is included in the cumulative pressure drop value; When the cumulative pressure drop exceeds the preset small bubble alarm threshold, a small bubble alarm is triggered and the blocking component is activated.

[0012] According to one embodiment of the present invention, the preset large bubble alarm threshold and the preset small bubble alarm threshold are dynamically adjusted according to the sensitivity level set by the host computer.

[0013] According to one embodiment of the present invention, the dual-channel air monitoring system further includes: The blood sensor component is integrated with the air monitoring component on the same monitoring housing. The blood sensing component includes a blood identification sensor; the blood identification sensor is electrically connected to the main control processing unit and is used to perform redundancy verification on the bubble determination result of the monitoring component by monitoring the optical parameters in the vein.

[0014] According to one embodiment of the present invention, the monitoring component is configured with a self-test mode, wherein, During the self-test phase, the air monitoring component performs a functional self-test, and the initial voltage of the blood recognition sensor is adjusted to a first preset value. During the blood priming stage, the main control processing unit and the protection processing unit respectively adaptively adjust the sensing unit in the air monitoring component to make the initial voltage of the sensing unit at a second preset value.

[0015] According to one embodiment of the present invention, the blood sensing component further includes at least a blood temperature sensor for monitoring blood temperature and a blood volume sensor for monitoring relative blood volume; The blood temperature sensor is used to monitor the temperature of venous blood in the venous tubing in real time to reflect changes in the thermal state of the blood. The blood volume sensor is used to monitor the blood volume in the venous tubing to characterize the blood circulation status and volume changes during dialysis.

[0016] The dual-channel air monitoring system for dialysis in this invention improves overall detection reliability by incorporating at least two independent sensing units within the air monitoring component. These units are independently detected by a main control processing unit and a protection processing unit, respectively. This ensures that the system can still detect bubbles even if an anomaly occurs in either detection path. Furthermore, the serial control logic between the main control processing unit and the protection processing unit allows the blocking component to be activated to block the venous tubing upon detection of a bubble by either unit. This enables a rapid response when bubbles appear, effectively reducing the risk of bubbles entering the body. Based on this structural design, the safety and stability of air monitoring during dialysis are improved without significantly increasing system complexity. Attached Figure Description

[0017] Figure 1 This is a structural block diagram of a dual-channel air monitoring system for dialysis in one embodiment. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] like Figure 1 As shown in the figure, this embodiment provides a structural block diagram of a dual-channel air monitoring system for dialysis. The system includes an air monitoring component disposed on the intravenous line and a monitoring component electrically connected thereto. The air monitoring component is used to collect status signals in the intravenous line, and the monitoring component is used to determine air bubbles based on the status signals and execute corresponding control operations. The implementation details of the technical solution of this embodiment are described in detail below.

[0020] In one embodiment, an air monitoring component is disposed on a vein conduit for detecting the state of air bubbles within the conduit. The air monitoring component includes at least two sensing units for independently acquiring loop signals, each sensing unit constituting an independent detection channel.

[0021] In the specific implementation, each sensing unit employs a detection structure based on the ultrasonic detection principle, installed on the venous tubing. It acquires loop signals by detecting changes in the acoustic properties of the blood. When air bubbles are present in the blood, their influence on the ultrasonic propagation characteristics causes changes in the detection signal, thus reflecting the presence and state of the air bubbles. Specifically, the loop signals output by each sensing unit are processed to form corresponding detection voltage values. When the blood is in a continuous and stable flow state, the detection voltage value remains within a relatively stable range; when air bubbles are present in the blood, the detection voltage value deviates, allowing for the identification of the air bubble state based on this change. Two sensing units acquire the detection signals of their respective channels and output them to different processing units to achieve independence between the detection channels.

[0022] like Figure 1 As shown, this embodiment includes a monitoring component, which comprises an independent main control processing unit and a protection processing unit. The main control processing unit is electrically connected to the first sensing unit in the air monitoring component, and the protection processing unit is electrically connected to the second sensing unit in the air monitoring component, thereby receiving the loop signals output from the corresponding detection channels.

[0023] During dialysis treatment, the main control processing unit and the protection processing unit process the received loop signals in real time and independently perform bubble detection. The two processing units operate independently of each other, and if an anomaly occurs in either processing path, the other processing path can still continue bubble detection, thereby improving the reliability of the system operation.

[0024] In terms of control logic, the main control processing unit and the protection processing unit form a series control relationship. When either processing unit detects the presence of an air bubble, it can trigger a control signal output and drive the blocking component installed on the venous line to perform a blocking operation, thereby achieving timely disconnection of the venous line. In practical applications, the blocking component can be an actuator used to clamp the blood line, such as a flow clamp. After receiving the control signal, it closes the venous line, thereby preventing air bubbles from entering the patient's body.

[0025] During system operation, the main control processing unit and the protection processing unit continuously monitor and judge the detection signals. When an abnormality is detected, they can quickly respond and execute control operations, thus forming a closed-loop processing mechanism from signal acquisition and judgment to control execution. Through the above structural setup, the system has independent redundancy capabilities at both the detection and control levels, thereby improving the safety level during dialysis.

[0026] In one embodiment, the main control processing unit and the protection processing unit respectively filter the received loop signal to obtain the current detection voltage value for bubble detection. In the specific implementation, the loop signal output by the air monitoring component is collected at a preset sampling frequency, which can be 2000 sps, and stored in a buffer space. In practical applications, the buffer space can have a capacity of 128 sampling points, and the data in the buffer space is updated in a first-in-first-out manner with a data update interval of 0.5 ms.

[0027] Subsequently, mean filtering is performed on a preset number of sampled data points to obtain a smoothed detection voltage value. Specifically, during data processing, the 20 most recent sampled data points are selected from the buffer space every 10ms for mean filtering to obtain the current detection voltage value. And the corresponding judgment frequency is 100 times / second.

[0028] By filtering the original signal, random noise and fluctuations during the sampling process can be effectively suppressed, the stability of the signal can be improved, and a reliable data basis can be provided for subsequent bubble determination.

[0029] In one embodiment, the main control processing unit and the protection processing unit dynamically update the reference value based on the current detected voltage value and the reference value at the previous moment, respectively, to obtain the current reference value. In the specific implementation, let the reference value at the previous moment be... The current detected voltage value is Then the current benchmark value The update relationship based on the recursive method is represented as follows:

[0030] During dialysis, the detection signal may drift slowly due to changes in blood flow and tubing deformation. Therefore, the baseline value is continuously updated using a recursive method to maintain historical stability to a large extent. At the same time, the current signal changes are tracked in minute increments, so that the baseline value can be dynamically adjusted as the signal in the venous tubing drifts slowly.

[0031] Updated baseline value As a reference value, used to compare with the current detected voltage value A comparison is performed to determine the bubble.

[0032] In one embodiment, when updating the reference value, a first difference between the current detected voltage value and the reference value at the previous moment is calculated, namely:

[0033] The current detection voltage value corresponding to the first difference exceeding the preset abnormal threshold is then discarded as an abnormal value.

[0034] In actual operation, the detection signal may be affected by transient interference or sudden changes, resulting in abnormal fluctuations. If these fluctuations are directly involved in the baseline value update, the baseline value will deviate from the normal range. Therefore, identifying and removing abnormal data before updating the baseline value makes the update process more stable, thereby ensuring the reliability of subsequent bubble determination.

[0035] Specifically, when At that time, determine the current detection voltage value. This is abnormal data; in this case, the baseline value is not updated. .when When the time is right, the baseline value is updated according to the recursive formula.

[0036] The above-mentioned outlier removal mechanism can effectively avoid the impact of transient interference or sudden signal on the update of the benchmark value, thereby improving the stability of the benchmark value and the accuracy of subsequent bubble determination.

[0037] In one embodiment, bubble detection includes large bubble detection logic. Specifically, a second difference between the current detection voltage value and the current reference value is calculated, and the second difference can be specifically expressed as:

[0038] The effect of air bubbles on the detection signal is reflected by the calculated second difference. When large air bubbles appear in the venous tubing, the detection voltage value... A significant decrease, resulting in the second difference. Increase. When the second difference... When the preset large air bubble alarm threshold is exceeded, a large air bubble is detected and an alarm signal is triggered. At the same time, the blocking component is driven to perform a blocking operation on the venous line to prevent the air bubble from entering the patient's body.

[0039] In one embodiment, bubble detection further includes small bubble detection logic. Similar to the second difference definition in the large bubble detection logic, small bubble detection is also based on... Calculations are performed, but identification is achieved using a cumulative voltage drop within a sliding time window, rather than a single threshold comparison. Specifically, within a preset sliding time window, the second difference between the detected voltage value and the reference value is continuously monitored. In each detection cycle, when the second difference at a single detection point... Within the preset small bubble amplitude range (e.g.) If the difference is zero, the difference is included in the cumulative pressure drop value. Otherwise, the detection point is recorded as 0 and not included in the cumulative value.

[0040] In practical applications, a single small bubble has a relatively small impact on the detection signal, making it difficult to identify through a single judgment. Therefore, multiple small changes are accumulated within a time window. Specifically, the detection voltage value is continuously collected based on a sampling rhythm of once every 10ms, and the collected multiple detection points are statistically processed every 500ms to form a cumulative voltage drop value corresponding to a statistical period. Based on this, a sliding accumulation processing is performed on the cumulative voltage drop value sequence formed with a statistical period of 500ms, with a sliding time window of 60 seconds. The corresponding window length is 120 data points, and the cumulative voltage drop value is continuously calculated through a sliding update method.

[0041] When the cumulative pressure drop exceeds the preset small bubble alarm threshold, it is determined that there is a continuous small bubble input within the time window, thereby triggering the small bubble alarm and driving the blocking component to perform the blocking operation of the vein.

[0042] The aforementioned cumulative mechanism based on time windows enables effective identification of continuous microbubbles, avoiding the problem of difficulty in detection with a single test.

[0043] In one embodiment, the alarm thresholds for large bubbles and small bubbles are dynamically adjusted based on the sensitivity levels set by the host computer. In actual dialysis processes, different application scenarios have different requirements for bubble detection sensitivity. Therefore, by setting different sensitivity levels on the host computer and adjusting the alarm thresholds accordingly, the system can achieve a balance between detection sensitivity and false alarm rate, thereby meeting the usage requirements under different operating conditions.

[0044] Specifically, for the determination of large bubbles, the alarm threshold for large bubbles can be set according to the following rules: When set to low sensitivity, the large bubble alarm threshold is expressed as follows: The corresponding bubble volume is approximately 0.2 ml; When set to medium sensitivity, the large bubble alarm threshold is expressed as follows: The corresponding bubble volume is approximately 0.1 ml; When set to high sensitivity, the large bubble alarm threshold is expressed as follows: The corresponding bubble volume is approximately 0.02 ml.

[0045] For the detection of small bubbles, the alarm threshold for small bubbles can be set according to the following rules: When set to low sensitivity, the small bubble alarm threshold is expressed as follows: The corresponding bubble rate is approximately 0.9 ml / min; When set to medium sensitivity, the small bubble alarm threshold is expressed as follows: This corresponds to a bubble rate of approximately 0.6 ml / min; When set to high sensitivity, the small bubble alarm threshold is expressed as follows: The corresponding bubble rate is approximately 0.3 ml / min.

[0046] By setting alarm thresholds in different levels, the system can adjust the detection sensitivity and false alarm rate according to different application requirements, thereby improving the system's adaptability and configurability.

[0047] In one embodiment, the dual-channel air monitoring system also includes a blood sensing component, which is integrated with the air monitoring component onto the same monitoring housing to form an integrated detection module. By structurally integrating air monitoring and blood-related parameter detection, the complexity of piping connections caused by the dispersed arrangement of multiple modules can be reduced, and the risks of installation and operation can be lowered.

[0048] The blood sensing component includes a blood identification sensor, which is electrically connected to the main control processing unit and is used to monitor optical parameters within the venous tubing in real time. During dialysis, when a large amount of air enters the venous tubing, it causes changes in the optical signal transmission characteristics, resulting in a decrease in the light intensity received by the blood identification sensor.

[0049] The main control processing unit processes the corresponding detection signal based on changes in light intensity, converting the light intensity changes into changes in pressure drop to characterize abnormal states in the venous tubing. When a large number of bubbles appear, the pressure drop change corresponding to the blood recognition sensor increases, which can then be used to identify the abnormal bubble state.

[0050] Based on this, the detection results of the blood recognition sensor are used to redundantly verify the bubble detection results of the main control processing unit and the protection processing unit. When the detection results of the air monitoring channel are consistent with those of the blood recognition channel, the reliability of the judgment is improved. When any channel malfunctions, the other channel can still provide auxiliary judgment information, thereby improving the overall safety and stability of the detection.

[0051] In one embodiment, the monitoring component is configured with a self-test mode for initializing and calibrating the detection channel at different stages of the dialysis process.

[0052] During the self-test phase, a functional self-test is performed on the air monitoring component to detect the signal acquisition capability and channel status of the sensing unit in the air monitoring component. At the same time, the blood recognition sensor is initialized and adjusted so that its output voltage is adjusted to the first preset value range, such as about 4V, in order to establish a stable initial detection benchmark.

[0053] During the blood intake stage, as blood enters the venous tubing, the main control processing unit and the protection processing unit adaptively adjust their respective corresponding sensing units to adjust the output voltage of the sensing units to a second preset value range, such as about 3.6V, so that the detection signal matches the acoustic characteristics of blood under actual working conditions.

[0054] By using the aforementioned phased adjustment method, the air monitoring channel and the blood recognition channel can be in the appropriate working range at different operating stages, thereby improving the signal stability and judgment accuracy in subsequent detection processes.

[0055] In one embodiment, the blood sensing component further includes a blood temperature sensor and a blood volume sensor, which are integrated with the air monitoring component on the same monitoring housing.

[0056] The blood temperature sensor is used to monitor the temperature of venous blood in the venous tubing in real time and output a corresponding temperature signal to reflect changes in the thermal state of the blood during dialysis. In practical applications, the blood temperature sensor is electrically connected to the main control processing unit. The main control processing unit judges the thermal state of the blood based on the temperature signal. When an abnormal venous blood temperature is detected, it can trigger corresponding safety control strategies to adjust or block the venous tubing to avoid the abnormal temperature from affecting the patient.

[0057] A blood volume sensor is used to monitor changes in blood volume within the venous tubing. By detecting changes in blood volume during dialysis, it obtains parameters reflecting hemodynamic status, characterizing the blood circulation status and volume changes during dialysis. Specifically, the venous blood volume data acquired by the blood volume sensor reflects the combined impact of dialyzer consumption and the venous tubing on blood volume changes. This data can be jointly analyzed with data acquired by the arterial blood volume monitoring module to calculate the circulation ratio parameters during extracorporeal circulation. In practical applications, the blood volume sensor is electrically connected to the main control processing unit. Based on the blood volume data and circulation ratio parameters, the main control processing unit can assess the blood circulation status during dialysis, providing data support for medical staff to adjust the dialysis process and improve the adequacy and effectiveness of dialysis treatment.

[0058] By integrating blood temperature detection and blood volume detection functions into the same monitoring component, blood-related parameters can be monitored simultaneously while air monitoring is being implemented. This improves the overall functional integration of the system and reduces the structural complexity and operational burden caused by multiple independent modules.

[0059] In the above embodiments, the dual-channel air monitoring system, by setting at least two independent sensing units on the intravenous line and connecting them respectively to the main control processing unit and the protection processing unit, allows bubble detection to be performed in parallel in two independent channels. This ensures that even if one channel experiences an anomaly or malfunction, the other channel can continue to detect bubbles, improving the system's fault tolerance and operational reliability. Simultaneously, the main control processing unit and the protection processing unit independently detect bubbles based on their respective acquired loop signals, and form a linked control relationship with the blocking component through serial control logic. This allows either processing unit to trigger a blocking operation on the intravenous line upon detecting a bubble, enabling rapid response and timely handling of bubble risks and reducing the risk of bubbles entering the patient's body. Through the synergistic cooperation of the above structure and control methods, the system possesses redundancy and linkage capabilities at both the detection and execution layers, comprehensively improving the safety and stability of the dialysis process.

[0060] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0062] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A dual-channel air monitoring system for dialysis, characterized in that, include: An air monitoring component, installed on a vein line, includes at least two sensing units for independently acquiring loop signals; The monitoring component includes a main control processing unit and a protection processing unit that are independent of each other; the main control processing unit is electrically connected to a first sensing unit in the air monitoring component; the protection processing unit is electrically connected to a second sensing unit in the air monitoring component. The main control processing unit and the protection processing unit respectively determine the presence of bubbles based on the received loop signals. When the main control processing unit and / or the protection processing unit determine that a bubble exists, the blocking component set on the vein is driven to perform a vein blocking operation through serial control logic.

2. The dual-channel air monitoring system for dialysis according to claim 1, characterized in that, The main control processing unit and the protection processing unit respectively filter the received loop signal to obtain the current detection voltage value used for bubble detection.

3. The dual-channel air monitoring system for dialysis according to claim 2, characterized in that, The main control processing unit and the protection processing unit dynamically update the current reference value based on the current detection voltage value and the reference value at the previous moment, and determine the bubble by comparing the current reference value with the current detection voltage value.

4. The dual-channel air monitoring system for dialysis according to claim 3, characterized in that, When updating the reference value, the first difference between the current detection voltage value and the reference value at the previous moment is calculated, and the current detection voltage value corresponding to the first difference exceeding the preset abnormal threshold is regarded as an abnormal value and removed.

5. The dual-channel air monitoring system for dialysis according to claim 3, characterized in that, The bubble detection includes logic for detecting large bubbles: Calculate the second difference between the current detected voltage value and the current reference value; When the second difference exceeds the preset large bubble alarm threshold, a large bubble alarm is triggered and the blocking component is activated.

6. The dual-channel air monitoring system for dialysis according to claim 5, characterized in that, The bubble detection also includes small bubble detection logic: Within a preset sliding time window, the second difference between the current detection voltage value and the current reference value of a single detection point is continuously monitored. When the second difference is within the preset small bubble amplitude range, it is included in the cumulative pressure drop value; When the cumulative pressure drop exceeds the preset small bubble alarm threshold, a small bubble alarm is triggered and the blocking component is activated.

7. The dual-channel air monitoring system for dialysis according to claim 6, characterized in that, The preset large bubble alarm threshold and the preset small bubble alarm threshold are dynamically adjusted according to the sensitivity level set by the host computer.

8. The dual-channel air monitoring system for dialysis according to claim 1, characterized in that, The dual-channel air monitoring system also includes: The blood sensor component is integrated with the air monitoring component on the same monitoring housing. The blood sensing component includes a blood identification sensor; the blood identification sensor is electrically connected to the main control processing unit and is used to perform redundancy verification on the bubble determination result of the monitoring component by monitoring the optical parameters in the vein.

9. The dual-channel air monitoring system for dialysis according to claim 8, characterized in that, The monitoring component is configured with a self-test mode, wherein, During the self-test phase, the air monitoring component performs a functional self-test, and the initial voltage of the blood recognition sensor is adjusted to a first preset value. During the blood priming stage, the main control processing unit and the protection processing unit respectively adaptively adjust the sensing unit in the air monitoring component to make the initial voltage of the sensing unit at a second preset value.

10. The dual-channel air monitoring system for dialysis according to claim 8, characterized in that, The blood sensing component further includes at least a blood temperature sensor for monitoring blood temperature and a blood volume sensor for monitoring relative blood volume. The blood temperature sensor is used to monitor the temperature of venous blood in the venous tubing in real time to reflect changes in the thermal state of the blood. The blood volume sensor is used to monitor the blood volume in the venous tubing to characterize the blood circulation status and volume changes during dialysis.

Images