A method and apparatus for detecting red blood cell extravasation

Abstract

The application discloses a red blood cell overflow detection method and device, and belongs to the field of blood separation. The device comprises a light source module, which is used for emitting light of a first wavelength and a second wavelength to a blood component collecting tube; a photoelectric sensor, which is arranged on the same side of the collecting tube and is used for receiving reflected light and converting the reflected light into a current signal; a signal processing circuit, which is electrically connected with the photoelectric sensor and is used for amplifying and filtering the current signal and outputting a voltage signal reflecting the intensity of the reflected light; and a controller, which is electrically connected with the signal processing circuit and the light source module and is configured to judge the red blood cell overflow state based on the intensity ratio of the reflected light of the first wavelength to the second wavelength. The application adopts the intensity ratio of the reflected light of the two wavelengths as the judgment basis, arranges the light source and the sensor on the same side, and does not need to flatten the pipeline; the signal processing circuit adopts a two-stage amplification plus a direct-current blocking capacitor structure, effectively filters out environmental light interference, can stably detect a red blood cell concentration as low as 0.5%, and has a low misjudgment rate.

Description

Technical Field

[0001] This invention relates to the field of blood separation technology, and in particular to a method and apparatus for detecting red blood cell spillage. Background Technology

[0002] Apheresis blood separators are used to separate whole blood into various components, such as platelets, red blood cells, and plasma. These components flow out of the separator individually through blood collection tubes. Typically, the collection tubes of the blood separator are continuously monitored to detect any undesirable spillage of blood components into the collection tube. For example, monitoring for red blood cells spilling into a collection tube containing only platelets.

[0003] The traditional technique for monitoring red blood cell spillage in the collection tube is to measure the color index of the non-red blood components flowing through the tube. This measurement is performed at a point downstream of the blood separator. By using a green light source and measuring the optical density of the non-red blood components, the total number of particles in the flowing non-red blood components and the green light absorption rate of the non-red blood components can be monitored. An increase in green light absorption rate relative to optical density is associated with the occurrence of red blood cell spillage.

[0004] This type of detection equipment typically requires physically positioning the light source on one side of the collection tube and the photodetector on the other side. For the system to operate effectively, the portion of the collection tube closest to the light source must provide a roughly flat surface for both the light source and the photodetector. Relatively expensive solutions or custom-made containers are required to create this flat surface, thereby improving optical efficiency. For example, the collection tube can be flattened.

[0005] Another problem with this type of detection equipment is that measuring optical density requires measuring the intensity of light received by the optical sensor. Artifacts such as dirt particles that affect the intensity of light received by the optical sensor often lead to false positives for red blood cell overflow.

[0006] Therefore, there is an urgent need for a more sensitive detection device to detect red blood cell spillage in blood collection tubes. Summary of the Invention

[0007] To achieve the above-mentioned objectives and other advantages of the present invention, a first objective of the present invention is to provide a red blood cell spillage detection device for monitoring whether red blood cells are mixed in with a blood component collection tube, comprising: A light source module is used to emit light of a first wavelength and a second wavelength into the collection tube; A photoelectric sensor, disposed on the same side of the collecting tube, is used to receive reflected light of the first wavelength and the second wavelength reflected back by the liquid inside the tube, and convert it into a current signal; The signal processing circuit, electrically connected to the photoelectric sensor, is used to amplify and filter the current signal and output a voltage signal reflecting the intensity of the reflected light. The controller is electrically connected to the signal processing circuit and the light source module. The controller is configured to control the operating timing of the light source module, receive and process the voltage signal, and determine the red blood cell overflow state based on the ratio of the reflected light intensity of the first wavelength to the second wavelength.

[0008] Furthermore, the signal processing circuit includes: The first amplification stage is connected to the photoelectric sensor and is used to convert the current signal into a first voltage signal; A DC blocking element is connected to the output terminal of the first amplifier stage to filter out the DC component caused by ambient light in the first voltage signal and retain the AC component caused by the light source. The second amplification stage is connected to the output terminal of the DC blocking element and is used to amplify the AC component a second time and output a second voltage signal to the controller.

[0009] Furthermore, the first amplification stage is a transimpedance amplifier, and the value of its feedback resistor is set to generate an output voltage of 0.4V to 0.6V for a unit microamp input current; The second amplification stage is an in-phase amplifier with a magnification factor set to 50 to 100 times.

[0010] Furthermore, the light source module includes: A first light source used to emit light of the first wavelength; A second light source used to emit light of a second wavelength; The first light source and the second light source are arranged at a symmetrical tilt angle relative to the photoelectric sensor, so that the light emitted by them can be reflected and focused onto the photoelectric sensor after shining on the collecting tube.

[0011] Furthermore, it also includes: The housing, in which the first light source, the second light source, and the photoelectric sensor are all fixed; The circuit board is tightly attached to the bottom of the housing, and the circuit board is made of an opaque material; A light guide column, disposed inside the housing and corresponding to the photoelectric sensor, is used to guide reflected light to the photoelectric sensor; An elastic element is disposed inside the housing and connected to the light guide post, for applying an elastic force toward the collection tube to the light guide post, so that the light guide post is in close contact with the outer wall of the collection tube when in the detection state.

[0012] Furthermore, the housing is also provided with light guide columns corresponding to the first light source and the second light source, respectively, for guiding the light emitted by them to the collection tube.

[0013] Furthermore, the controller includes: A digital-to-analog converter interface is used to output analog control signals to the light source module to adjust the driving current of the first light source and the second light source respectively; An analog-to-digital converter interface is used to receive and digitize the voltage signal output by the signal processing circuit. Furthermore, the controller is configured to execute an initialization calibration procedure, which includes: With the collection tube empty, the average intensity of the reflected light at the first wavelength and the average intensity of the reflected light at the second wavelength were obtained respectively. Calculate the initial ratio of the average intensity of reflected light at the first wavelength to the average intensity of reflected light at the second wavelength; The driving current of the first light source or the second light source is adjusted through the digital-to-analog conversion interface so that the initial ratio approaches a preset reference value.

[0014] Further, the step of obtaining the average value of the reflected light intensity of the first wavelength and the average value of the reflected light intensity of the second wavelength respectively when the collection tube is empty includes: The light source is controlled to work at a preset frequency for N cycles. In each cycle, the reflected light intensity is measured when the light source is lit and when the light source is turned off. Calculate the average reflected light intensity during N cycles when the light is on and the average reflected light intensity when the light is off; Subtracting the average value when the light is on from the average value when the light is off gives the average value of the reflected light intensity after eliminating ambient light interference.

[0015] Furthermore, the first wavelength is red light with a wavelength range of 700 to 710 nm; the second wavelength is green light with a wavelength range of 540 to 550 nm.

[0016] Furthermore, the controller is also configured to: Calculate the ratio of the intensity of reflected light at the first wavelength to the intensity of reflected light at the second wavelength; The ratio is compared with a preset threshold. If the ratio exceeds the preset threshold, it is determined that red blood cell spillage has occurred, and an alarm signal is issued through the communication module.

[0017] A second objective of this invention is to provide a method for detecting red blood cell spillage, employing the aforementioned apparatus and comprising the following steps: The light source module emits light of the first and second wavelengths into the blood component collection tube; The first and second wavelengths of reflected light reflected back from the liquid inside the tube are received by a photoelectric sensor and converted into current signals. The current signal is amplified and filtered by a signal processing circuit to output a voltage signal that reflects the intensity of the reflected light. The controller receives and processes the voltage signal, and determines the red blood cell overflow status based on the ratio of the reflected light intensity of the first wavelength to the second wavelength.

[0018] Furthermore, the step of amplifying and filtering the current signal through a signal processing circuit to output a voltage signal reflecting the intensity of the reflected light includes: The current signal is converted into a first voltage signal through a first amplification stage; The DC component caused by ambient light in the first voltage signal is filtered out by the DC blocking element, while the AC component caused by the light source is retained. The AC component is amplified a second time by a second amplification stage to output a second voltage signal.

[0019] Furthermore, an initialization calibration step is included before performing the red blood cell spill detection: When the collection tube is empty, the average value of the reflected light intensity of the first wavelength and the average value of the reflected light intensity of the second wavelength are obtained by the controller. Calculate the initial ratio of the average intensity of reflected light at the first wavelength to the average intensity of reflected light at the second wavelength; By adjusting the driving current of the first or second light source, the initial ratio is made to approach a preset reference value.

[0020] Furthermore, the step of obtaining the average value of the first wavelength reflected light intensity and the average value of the second wavelength reflected light intensity respectively through the controller when the collection tube is empty includes: The light source is controlled to work at a preset frequency for N cycles. In each cycle, the reflected light intensity is measured when the light source is lit and when the light source is turned off. Calculate the average reflected light intensity during N cycles when the light is on and the average reflected light intensity when the light is off; Subtract the average value when the light is on from the average value when the light is off to get the average value of the reflected light intensity after eliminating ambient light interference.

[0021] Furthermore, the step of determining the state of red blood cell overflow includes: Calculate the ratio of the intensity of reflected light at the first wavelength to the intensity of reflected light at the second wavelength; The ratio is compared with a preset threshold. If the ratio exceeds the preset threshold, it is determined that red blood cell overflow has occurred, and an alarm signal is issued.

[0022] Compared with the prior art, the beneficial effects of the present invention are: This invention places the light source and photoelectric sensor on one side of the blood component collection tube, which facilitates the installation of the sensor and the tube. It also does not have special requirements for the shape of the tube, and there is no need to flatten the collection tube or customize a collection tube with a flat surface. It has a wider range of applications and lower costs.

[0023] This invention uses photoelectric sensors to collect and compare the reflected light intensity of red and green light sources to determine the leakage of red blood cells in plasma or platelets. This greatly reduces the possibility of misjudgment caused by the influence of artifacts such as dirt particles on the reflected light intensity of a single light source in traditional detection equipment, making the detection more sensitive and the detection results more reliable.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 A schematic diagram illustrating an application scenario for a red blood cell overflow sensor; Figure 2 Diagram of the red blood cell overflow sensor structure; Figure 3 Red blood cell spill detection process Figure 1 ; Figure 4 Initialize the calibration process Figure 1 ; Figure 5 This is a block diagram of the electrical control for a red blood cell spillage sensor. Figure 6 This is a circuit diagram for an LED driver. Figure 7 This is a circuit diagram for signal processing. Figure 8 Red blood cell spill detection process Figure 2 ; Figure 9 Initialize the calibration process Figure 2 ; Figure 10 Flowchart for obtaining the average value of reflected light intensity; Figure 11 This is a flowchart of the signal processing procedure. Figure 12 Flowchart for determining the state of red blood cell spillage; Figure 13 A schematic diagram of computer equipment; Figure 14 This is a schematic diagram of a computer-readable storage medium. Detailed Implementation

[0026] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0027] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0028] The drawing numbers in this application are only used to distinguish the steps in the scheme and are not used to limit the execution order of the steps. The specific execution order is as described in the specification.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0030] This invention provides a method and apparatus for detecting red blood cell spillage, used to monitor a transparent blood tubing downstream of a blood separator to detect the presence of red blood cells in collection tubes for different blood components (such as platelets). Figure 1 As shown, red and green light sources are positioned relative to the blood vessel, directing the red light towards the blood vessel and the blood components flowing within it, respectively. The red light source generates red reflected light from red blood cells, with its intensity increasing with red blood cell concentration. The green light source generates green reflected light from red blood cells, with its intensity decreasing with increasing red blood cell concentration. These two reflected lights are sensed by one or two photoelectric sensors. The output is provided by calculating the ratio of the red to green reflected light intensities.

[0031] This invention is particularly applicable to the continuous monitoring of one or more blood collection tubes at one or more locations downstream of a continuous blood separator to detect an undesirable situation where blood components (red blood cells) spill into the collection tubes. The specific solution is as follows: Example 1 A red blood cell spillage detection device is used to monitor whether red blood cells are mixed in with blood component collection tubes, such as... Figure 2 , Figure 5 As shown, it includes: A light source module is used to emit light of a first wavelength and a second wavelength into the collection tube; A photoelectric sensor, disposed on the same side of the collecting tube, is used to receive reflected light of the first wavelength and the second wavelength reflected back by the liquid inside the tube, and convert it into a current signal; The signal processing circuit, electrically connected to the photoelectric sensor, is used to amplify and filter the current signal and output a voltage signal reflecting the intensity of the reflected light. The controller is electrically connected to the signal processing circuit and the light source module. The controller is configured to control the operating timing of the light source module, receive and process the voltage signal, and determine the red blood cell overflow state based on the ratio of the reflected light intensity of the first wavelength to the second wavelength.

[0032] Preferably, the controller controls the two light sources in the light source module to alternately light up and turn off at a set frequency, and then only one photoelectric sensor collects the intensity of the reflected light from the two light sources. Since the reflected light from the two light sources occurs in different time intervals, interference between the reflected light can be prevented.

[0033] Preferably, the two light sources and the photoelectric sensor are physically located on the same side of the collection tube. In this configuration, the blood component collection tube can be automatically loaded into the device of the present invention. Furthermore, the structure and arrangement of the present invention eliminates the need for cuvettes and flattening of the tubing, reduces the likelihood of misjudging red blood cell spillage, and provides efficient and sensitive detection of red blood cell spillage.

[0034] In other embodiments, the outputs of the two light sources in the light source module are continuous, requiring each light source to be equipped with a photoelectric sensor to collect the reflected light intensity of its respective light source. Then, the ratio of the red reflected light intensity to the green reflected light intensity is calculated to determine whether red blood cells have leaked from the blood component collection tube.

[0035] In some embodiments, such as Figure 2 As shown, the light source module includes: A first light source is used to emit light of a first wavelength; preferably, the first wavelength is red light, that is, the first light source is a red LED light source with a wavelength range of 700 to 710 nm, which ensures the accuracy of the light source wavelength and helps to ensure the accuracy of the detection results.

[0036] A second light source is used to emit light of a second wavelength; preferably, the second wavelength is green light, that is, the second light source is a green LED light source with a wavelength range of 540 to 550 nm, which ensures the accuracy of the light source wavelength and helps to ensure the accuracy of the detection results.

[0037] The first light source and the second light source are arranged at a symmetrical tilt angle relative to the photoelectric sensor, so that the light emitted by them can be reflected and focused onto the photoelectric sensor after shining on the collecting tube.

[0038] In some embodiments, such as Figure 2 As shown, it also includes: The housing, in which the first light source, the second light source, and the photoelectric sensor are all fixed; The circuit board is tightly attached to the bottom of the housing, and the circuit board is made of an opaque material; A light guide column, disposed inside the housing and corresponding to the photoelectric sensor, is used to guide reflected light to the photoelectric sensor; An elastic element, disposed within the housing and connected to the light guide post, applies an elastic force toward the collection tube to the light guide post, causing the light guide post to adhere tightly to the outer wall of the collection tube during the detection state. Preferably, the elastic element is a spring.

[0039] In this embodiment, the top surface of the outer shell is provided with a spring and a light guide column structure for fitting the collection tube, so as to isolate ambient light interference to the greatest extent. Figure 2 In the photoelectric sensor, the light guide column is held in place by a spring and can move up and down within a certain range. When detecting the overflow of red blood cells in the detection tube, it can be pressed down by the tube to make it fit tightly against the tube and reduce interference from ambient light.

[0040] Furthermore, the housing is also equipped with light guide pillars corresponding to the first and second light sources, respectively, to guide the emitted light to the collection tube. Specifically, the red LED light source, the green LED light source, and the photoelectric sensor are each equipped with a light guide pillar to guide the light path and reduce light loss during propagation. The red LED light source, the green LED light source, and their light guide pillars are arranged symmetrically at a certain tilt angle relative to the photoelectric sensor, facilitating the entry of reflected light from the blood component collection tube into the light guide pillar of the intermediate photoelectric sensor. The reflected light is then guided by the light guide pillar to the photoelectric sensor, which converts the received reflected light into an electrical signal for processing by the sensor circuit board.

[0041] Figure 2 In the sensor housing, the red LED light source, green LED light source, and photoelectric sensor are all fixed inside the sensor housing and soldered onto the sensor circuit board below. The bottom surface of the sensor housing and the circuit board are tightly fitted and are both made of opaque material, enclosing the red and green light sources and photoelectric sensor. The entire sensor must be arranged close to the blood component collection tube to minimize ambient light interference and ensure that the light emitted and reflected by the red and green light sources can be effectively propagated.

[0042] like Figure 3As shown, red and green light sources are pointed at the blood component collection tube, which will be monitored for the presence or leakage of red blood cells. The intensity of red and green light reflection can occur within the same time interval; in this case, two identical photoelectric sensors are required to collect the intensity of red and green light reflection, respectively. However, in a preferred embodiment, the intensity of red and green light reflection can be collected alternately at a shorter fixed interval; in this embodiment, only one sensor can be provided, which responds to red light reflection in one time interval and green light reflection in another.

[0043] After collecting the intensity of red and green reflected light, the controller calculates the ratio of the intensity of red reflected light (i.e., the intensity of reflected light at the first wavelength) to the intensity of green reflected light (i.e., the intensity of reflected light at the second wavelength), and compares the ratio with a set threshold. If the ratio is less than the threshold, the blood separation process proceeds normally; if the ratio is greater than the threshold, it is determined that red blood cell overflow has occurred, and an alarm signal is issued through the communication module. The alarm signal can take the form of an audible and visual alarm or a pop-up alarm to alert the blood separator operator that red blood cell overflow has occurred.

[0044] In some embodiments, the controller is configured to execute an initialization calibration procedure, such as Figure 4 As shown, the initialization calibration procedure includes: With the collection tube empty, the average intensity of the reflected light at the first wavelength and the average intensity of the reflected light at the second wavelength were obtained respectively. Specifically, when the collection tube is empty, the steps of obtaining the average intensity of the first wavelength reflected light and the average intensity of the second wavelength reflected light respectively include: The light source is controlled to work at a preset frequency for N cycles. In each cycle, the reflected light intensity is measured when the light source is lit and when the light source is turned off. Calculate the average reflected light intensity during N cycles when the light is on and the average reflected light intensity when the light is off; Subtracting the average value when the light is on from the average value when the light is off gives the average value of the reflected light intensity after eliminating ambient light interference.

[0045] For example, initially, an empty, dried blood collection tube is placed in the red blood cell overflow sensor, with both the red and green LED light sources turned off. The red LED light source operates for N cycles, where one cycle represents the red LED light source turning on and off once at a frequency of 1 kHz. In each of the N cycles of the red LED light source operation, the measured values ​​of the reflected light intensity when the red LED light source is on and when the red LED light source is off are collected and stored, and the average value of the reflected light intensity is calculated for N cycles, as shown in the following formula: in, This represents the average value of the measured intensity of reflected light from the red LED light source. To collect the average value of the reflected light intensity measured N times when the red LED light source is on, This is the average value of the reflected light intensity measured N times when the red LED light source is turned off.

[0046] After calculating the average intensity of the reflected light from the red LED light source, the red LED light source is turned off. The green LED light source operates in the same manner, collecting, storing, and calculating the average intensity of the reflected light from the green LED light source.

[0047] Calculate the initial ratio of the average intensity of reflected light at the first wavelength to the average intensity of reflected light at the second wavelength; The driving current of the first light source or the second light source is adjusted through the digital-to-analog conversion interface so that the initial ratio approaches a preset reference value.

[0048] Specifically, after calculating the average reflected light intensity of both the red and green LED light sources, the ratio of the reflected light intensity of the red LED light source to that of the green LED light source is calculated and adjusted to 1 as a baseline value. This can be achieved by adjusting the current supplied to either the green or red LED light source; only one needs to be adjusted. It is important to note that if the calculated ratio is not 1 after this initialization process, the steps of collecting and calculating the average reflected light intensity of the red and green LED light sources must be repeated after adjusting the current supplied to either the green or red LED light source. If, after multiple adjustments to the current and recalculation of the average reflected light intensity, the ratio of the reflected light intensity of the red and green LED light sources cannot be adjusted to 1, the system should issue an alarm signal. It should also be understood that during the initialization process, the operating frequency of the red and green LED light sources, the number of times the reflected light intensity is collected (N), and the number of times the current of the red or green LED light source is adjusted can all be adjusted within a certain range.

[0049] like Figure 5 As shown, the power supply module converts the external 18~28V DC input voltage into the DC voltage required by each module. The circuit schematics for the red LED light source driver and the green LED light source driver modules are shown below. Figure 6 The diagram shows a constant current LED driver circuit with a single operational amplifier and a MOSFET. LED_RED_DA is the analog signal input terminal, connected to the processor's digital-to-analog converter interface. This analog signal voltage determines the magnitude of the LED driving current. The LED driving current is calculated using the following formula: in, This is the LED driving current. The LED_RED_DA analog signal voltage value. This is a current-limiting resistor.

[0050] The resistance value of R19 can be adjusted according to the driving current of the selected LED light source. In this example, R19 is 100Ω, and VLED_RED_DA is adjustable from 0 to 3.3V, so the driving current of the LED light source can be adjusted between 0 and 33mA. This achieves... Figure 4 The function in the sensor initialization process is to adjust the ratio of the reflected light intensity of the red LED light source to the reflected light intensity of the green LED light source to 1.

[0051] In some embodiments, Figure 7 This is a high-sensitivity photoelectric signal detection and conditioning circuit, used to convert the weak current signal from the photoelectric sensor that senses the intensity of red and green reflected light into a proportional voltage signal, amplify and filter it, and finally output a stable analog voltage. Specifically, the signal processing circuit includes: The first amplification stage is connected to the photoelectric sensor and is used to convert the current signal into a first voltage signal. Preferably, the first amplification stage is a transimpedance amplifier, and the resistance value of its feedback resistor is set to generate an output voltage of 0.4V to 0.6V for a unit microamp input current.

[0052] A DC blocking element is connected to the output terminal of the first amplification stage to filter out the DC component caused by ambient light in the first voltage signal and retain the AC component caused by the illumination of the light source. Preferably, the DC blocking element is a capacitor, and the filter cutoff frequency formed by its capacitance value and the input impedance of the subsequent circuit is lower than the operating modulation frequency of the light source module.

[0053] The second amplification stage is connected to the output terminal of the DC blocking element and is used to amplify the AC component a second time, outputting a second voltage signal to the controller. Preferably, the second amplification stage is a non-inverting amplifier with a magnification factor set to 50 to 100 times.

[0054] like Figure 7 As shown, this circuit consists of two stages of amplifiers. The first stage, U1A, is configured as a classic transimpedance amplifier (TIA). The non-inverting input (pin 3) is grounded to provide a virtual ground reference. The feedback resistor R1 (487kΩ, 0.1%) determines the conversion gain, and the feedback capacitor C1 (10pF) is used for phase compensation to prevent oscillation. Reflected light illuminates the photoelectric sensor (VTB1113BH), generating an induced current. The entire current flows through R1, resulting in the output voltage, as shown in the following formula: in, This is the output voltage of op-amp U1A.

[0055] In this embodiment, R1 is 487kΩ, that is, 1μA of induced current corresponds to 0.487V output.

[0056] In the second-stage amplifier circuit, the input signal is connected from the output terminal (pin 1) of U1A to the non-inverting input terminal (pin 5) of U1B via C4 (47nF / 50V). C4 acts as a DC-blocking and AC-passing circuit, preventing the DC component of the preceding circuit (induced current caused by ambient light) from affecting this stage circuit, allowing only the AC signal (induced current generated by the alternating on and off of the red and green LED light sources) to be amplified through U1B.

[0057] R6 (10KΩ / 0.1%) and R7 (10KΩ / 0.1%) form a voltage divider network, providing a reference voltage for the non-inverting input (pin 5) of U1B. R4 (10KΩ / 0.1%) and R5 (150Ω / 0.1%) form a feedback network, making U1B a non-inverting amplifier. The gain is calculated using the following formula: The output signal is output from pin 7 (OUT) of U1B. The induced current generated by the photoelectric sensor (VTB1113BH) is amplified twice to obtain an analog voltage signal that is easily acquired by the processor, as shown in the formula: This photoelectric signal conversion circuit possesses high-precision weak signal processing capabilities: the photoelectric sensor VTB1113BH used in the circuit has a wide wavelength response (330~720nm) and extremely low dark current (20pA), which can sensitively sense the intensity of reflected light from red and green LED light sources. The LF412CDR dual-channel high-speed operational amplifier has an input bias current of only 50pA and an offset voltage of 1mV. Paired with a high-precision conversion resistor R1 (487KΩ), it can accurately convert and amplify the weak current signal output by the photoelectric sensor, effectively preserving the detailed information of the weak light signal, making it suitable for scenarios with high signal accuracy requirements.

[0058] This photoelectric signal conversion circuit features a robust noise suppression design: multiple filtering components are incorporated throughout the circuit. R2, E1, C2 and R3, E2, C3 filter and regulate the circuit power supply, providing stable positive and negative voltages to the LF412CDR operational amplifier. Simultaneously, C4 acts as a DC-blocking and AC-passing capacitor, preventing DC components from the preceding circuit (induced current caused by ambient light) from affecting this stage. Only the effective AC signal (induced current generated by the alternating on / off state of the red and green LEDs) is amplified by the operational amplifier. This facilitates the acquisition and processing of the amplified signal by the subsequent circuit module (processor).

[0059] In some embodiments, the controller (i.e. Figure 5 The processor in the memory includes: A digital-to-analog converter interface is used to output analog control signals to the light source module to adjust the driving current of the first light source and the second light source respectively; An analog-to-digital converter interface is used to receive and digitize the voltage signal output by the signal processing circuit.

[0060] In this embodiment, the processor uses TI's STM32G431 series microcontroller. This series of microcontrollers features high clock frequency, strong data processing capabilities, and rich peripherals. It has a DA digital-to-analog converter interface to control the LED drive current and an AD analog-to-digital converter interface to collect the analog voltage signal of the photoelectric signal conversion module. It also has multiple communication interfaces (UART, CAN, USB, Ethernet, etc.) to communicate with the host computer and upload and display the collected and processed red blood cell concentration data.

[0061] In this embodiment, an RS485 interface is used to communicate with the host computer; the specific circuit will not be shown in detail.

[0062] Table 1 shows the ratio of red light reflectance to green light reflectance measured using plasma samples containing different concentrations of red blood cells. This indicates that the sensor designed in this embodiment can sensitively detect changes in red blood cell concentration in plasma samples. It is understandable that different plasma samples are not completely colorless and transparent, often exhibiting a slight yellow tint, and the color of plasma from different donors may also vary slightly. Therefore, the data in Table 1 only represents the data from the samples used in the experiment at that time. Differences between the data obtained from repeated experiments and the data in the table are normal, but the overall trend is consistent: the ratio gradually increases with increasing red blood cell concentration.

[0063] Table 1. Data on the concentration of red blood cells in plasma at different concentrations Example 2 A method for detecting red blood cell spillage employs the aforementioned apparatus. For a detailed description of the apparatus, please refer to the corresponding description in the apparatus embodiments described above; it will not be repeated here. Figure 3 , Figure 8 As shown, the method includes the following steps: S100: Light of the first and second wavelengths is emitted to the blood component collection tube through the light source module; Preferably, the controller controls the two light sources in the light source module to alternately light up and turn off at a set frequency, and then only one photoelectric sensor collects the intensity of the reflected light from the two light sources. Since the reflected light from the two light sources occurs in different time intervals, interference between the reflected light can be prevented.

[0064] In other embodiments, the outputs of the two light sources in the light source module are continuous, requiring each light source to be equipped with a photoelectric sensor to collect the reflected light intensity of its respective light source. Then, the ratio of the red reflected light intensity to the green reflected light intensity is calculated to determine whether red blood cells have leaked from the blood component collection tube.

[0065] Preferably, the first wavelength is red light, that is, the first light source is a red LED light source with a wavelength range of 700 to 710 nm; the second wavelength is green light, that is, the second light source is a green LED light source with a wavelength range of 540 to 550 nm, ensuring the accuracy of the light source wavelength, which is conducive to ensuring the accuracy of the detection results.

[0066] S200: Receive the reflected light of the first wavelength and the second wavelength reflected back by the liquid inside the tube through a photoelectric sensor, and convert it into a current signal; like Figure 3 As shown, red and green light sources are pointed at the blood component collection tube, which will be monitored for the presence or leakage of red blood cells. The intensity of red and green light reflection can occur within the same time interval; in this case, two identical photoelectric sensors are required to collect the intensity of red and green light reflection, respectively. However, in a preferred embodiment, the intensity of red and green light reflection can be collected alternately at a shorter fixed interval; in this embodiment, only one sensor can be provided, which responds to red light reflection in one time interval and green light reflection in another.

[0067] S300: The current signal is amplified and filtered by the signal processing circuit, and a voltage signal reflecting the intensity of the reflected light is output. Specifically, such as Figure 11 As shown, the step of amplifying and filtering the current signal through a signal processing circuit to output a voltage signal reflecting the intensity of reflected light includes: S310. The current signal is converted into a first voltage signal through a first amplification stage; like Figure 7 As shown, this circuit consists of two stages of amplifiers. The first stage, U1A, is configured as a classic transimpedance amplifier (TIA). The non-inverting input (pin 3) is grounded to provide a virtual ground reference. The feedback resistor R1 (487kΩ, 0.1%) determines the conversion gain, and the feedback capacitor C1 (10pF) is used for phase compensation to prevent oscillation. Reflected light illuminates the photoelectric sensor (VTB1113BH), generating an induced current. The entire current flows through R1, resulting in the output voltage, as shown in the following formula: in, This is the output voltage of op-amp U1A.

[0068] In this embodiment, R1 is 487kΩ, that is, 1μA of induced current corresponds to 0.487V output.

[0069] S320. The DC component caused by ambient light in the first voltage signal is filtered out by the DC blocking element, while the AC component caused by the light source being lit is retained. Preferably, the cutoff frequency of the DC blocking element is lower than the operating modulation frequency of the light source module, so that the ambient light response signal during the light source being turned off is effectively filtered out.

[0070] S330: The AC component is amplified a second time through the second amplification stage to output a second voltage signal.

[0071] In the second-stage amplifier circuit, the input signal is connected from the output terminal (pin 1) of U1A to the non-inverting input terminal (pin 5) of U1B via C4 (47nF / 50V). C4 acts as a DC-blocking and AC-passing circuit, preventing the DC component of the preceding circuit (induced current caused by ambient light) from affecting this stage circuit, allowing only the AC signal (induced current generated by the alternating on and off of the red and green LED light sources) to be amplified through U1B.

[0072] R6 (10KΩ / 0.1%) and R7 (10KΩ / 0.1%) form a voltage divider network, providing a reference voltage for the non-inverting input (pin 5) of U1B. R4 (10KΩ / 0.1%) and R5 (150Ω / 0.1%) form a feedback network, making U1B a non-inverting amplifier. The gain is calculated using the following formula: The output signal is output from pin 7 (OUT) of U1B. The induced current generated by the photoelectric sensor (VTB1113BH) is amplified twice to obtain an analog voltage signal that is easily acquired by the processor, as shown in the formula: .

[0073] In some embodiments, such as Figure 4 , Figure 9 As shown, an initialization calibration step is included before performing the red blood cell spill detection: S110. When the collection tube is empty, the average value of the reflected light intensity of the first wavelength and the average value of the reflected light intensity of the second wavelength are obtained by the controller. Specifically, such as Figure 10 As shown, the step of obtaining the average value of the first wavelength reflected light intensity and the average value of the second wavelength reflected light intensity through the controller when the collection tube is empty includes: S111. Control the light source to work at a preset frequency for N cycles, and collect the reflected light intensity measurement value when the light source is lit and the reflected light intensity measurement value when the light source is turned off in each cycle. S112. Calculate the average reflected light intensity during N cycles when the light is on and the average reflected light intensity when the light is off. S113. Subtract the average value when the light is on from the average value when the light is off to obtain the average value of the reflected light intensity after eliminating ambient light interference.

[0074] For example, initially, an empty, dried blood collection tube is placed in the red blood cell overflow sensor, with both the red and green LED light sources turned off. The red LED light source operates for N cycles, where one cycle represents the red LED light source turning on and off once at a frequency of 1 kHz. In each of the N cycles of the red LED light source operation, the measured values ​​of the reflected light intensity when the red LED light source is on and when the red LED light source is off are collected and stored, and the average value of the reflected light intensity is calculated for N cycles, as shown in the following formula: in, This represents the average value of the measured intensity of reflected light from the red LED light source. To collect the average value of the reflected light intensity measured N times when the red LED light source is on, This is the average value of the reflected light intensity measured N times when the red LED light source is turned off.

[0075] After calculating the average intensity of the reflected light from the red LED light source, the red LED light source is turned off. The green LED light source operates in the same manner, collecting, storing, and calculating the average intensity of the reflected light from the green LED light source.

[0076] S120. Calculate the initial ratio of the average intensity of reflected light at the first wavelength to the average intensity of reflected light at the second wavelength; S130. By adjusting the driving current of the first light source or the second light source, the initial ratio is made to approach a preset reference value.

[0077] Specifically, after calculating the average reflected light intensity of both the red and green LED light sources, the ratio of the reflected light intensity of the red LED light source to that of the green LED light source is calculated and adjusted to 1 as a baseline value. This can be achieved by adjusting the current supplied to either the green or red LED light source; only one needs to be adjusted. It is important to note that if the calculated ratio is not 1 after this initialization process, the steps of collecting and calculating the average reflected light intensity of the red and green LED light sources must be repeated after adjusting the current supplied to either the green or red LED light source. If, after multiple adjustments to the current and recalculation of the average reflected light intensity, the ratio of the reflected light intensity of the red and green LED light sources cannot be adjusted to 1, the system should issue an alarm signal. It should also be understood that during the initialization process, the operating frequency of the red and green LED light sources, the number of times the reflected light intensity is collected (N), and the number of times the current of the red or green LED light source is adjusted can all be adjusted within a certain range.

[0078] S400: The controller receives and processes the voltage signal, and determines the red blood cell overflow state based on the ratio of the reflected light intensity of the first wavelength to the second wavelength.

[0079] Specifically, such as Figure 12 As shown, the step of determining the state of red blood cell overflow includes: S410. Calculate the ratio of the intensity of the reflected light at the first wavelength to the intensity of the reflected light at the second wavelength; that is, after collecting the intensity of the reflected light at the red and green wavelengths, the controller calculates the ratio of the intensity of the reflected light at the red wavelength to the intensity of the reflected light at the green wavelength. S420. Compare the ratio with a preset threshold; S430. If the ratio exceeds the preset threshold, it is determined that red blood cell overflow has occurred and an alarm signal is issued. The alarm signal can be in the form of an audible and visual alarm or a pop-up alarm to alert the blood separator operator that red blood cell overflow has occurred. S440. If the ratio does not exceed the preset threshold, the blood separation process will proceed normally.

[0080] Example 3 A computer device 500, such as Figure 13 As shown, the system includes a memory 510, a processor 520, and a computer program 530 stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of a red blood cell spillage detection method. For a detailed description of the method, please refer to the corresponding description in the above method embodiments; it will not be repeated here.

[0081] Example 4 A computer-readable storage medium, such as Figure 14 As shown, a computer program is stored thereon, which, when executed by a processor, implements the steps of a method for detecting red blood cell spillage. For a detailed description of the method, please refer to the corresponding description in the above method embodiments, and will not be repeated here.

[0082] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0083] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

[0084] The apparatus, computer device, and non-volatile computer storage medium and method provided in the embodiments of this specification are corresponding. Therefore, the apparatus, computer device, and non-volatile computer storage medium also have similar beneficial technical effects as the corresponding method. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the corresponding apparatus, computer device, and non-volatile computer storage medium will not be repeated here.

[0085] Those skilled in the art will also know that, besides implementing the controller in the form of purely computer-readable program code, the same functions can be achieved by logically programming the method steps, making the controller take the form of logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers (PLCs), and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the devices included within it for implementing various functions can also be considered structures within that hardware component. Alternatively, the devices for implementing various functions can be considered as both software units implementing the method and structures within a hardware component.

[0086] The systems, apparatuses, or units described in the above embodiments can be implemented by computer chips or physical entities, or by products with certain functions. For ease of description, the above apparatuses are described separately as various units based on their functions. Of course, when implementing one or more embodiments of this specification, the functions of each unit can be implemented in one or more software and / or hardware.

[0087] Those skilled in the art will understand that the embodiments of this specification can be provided as methods, systems, or computer program products. Therefore, the embodiments of this specification can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, the embodiments of this specification can take the form of computer program products implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0088] This specification is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this specification. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0089] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0090] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0091] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0092] This specification may be described in the general context of computer-executable instructions, such as program units, that are executed by a computer. Generally, program units include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This specification may also be practiced in distributed computing environments, where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program units may reside in local and remote computer storage media, including storage devices.

[0093] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0094] The above description is merely an embodiment of this specification and is not intended to limit the scope of one or more embodiments of this specification. Various modifications and variations can be made to one or more embodiments of this specification by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of one or more embodiments of this specification should be included within the scope of the claims of one or more embodiments of this specification.

Claims

1. A red blood cell spillage detection device for monitoring whether red blood cells are mixed in with a blood component collection tube, characterized in that, include: A light source module is used to emit light of a first wavelength and a second wavelength into the collection tube; A photoelectric sensor, disposed on the same side of the collecting tube, is used to receive reflected light of the first wavelength and the second wavelength reflected back by the liquid inside the tube, and convert it into a current signal; The signal processing circuit, electrically connected to the photoelectric sensor, is used to amplify and filter the current signal and output a voltage signal reflecting the intensity of the reflected light. The controller is electrically connected to the signal processing circuit and the light source module. The controller is configured to control the operating timing of the light source module, receive and process the voltage signal, and determine the red blood cell overflow state based on the ratio of the reflected light intensity of the first wavelength to the second wavelength.

2. The red blood cell spillage detection device as described in claim 1, characterized in that, The signal processing circuit includes: The first amplification stage is connected to the photoelectric sensor and is used to convert the current signal into a first voltage signal; A DC blocking element is connected to the output terminal of the first amplifier stage to filter out the DC component caused by ambient light in the first voltage signal and retain the AC component caused by the light source. The second amplification stage is connected to the output terminal of the DC blocking element and is used to amplify the AC component a second time and output a second voltage signal to the controller.

3. The red blood cell spillage detection device as described in claim 2, characterized in that, The first amplification stage is a transimpedance amplifier, and the value of its feedback resistor is set to generate an output voltage of 0.4V to 0.6V from a unit microamp input current; The second amplification stage is an in-phase amplifier with a magnification factor set to 50 to 100 times.

4. The red blood cell spillage detection device as described in claim 1, characterized in that, The light source module includes: A first light source used to emit light of the first wavelength; A second light source used to emit light of a second wavelength; The first light source and the second light source are arranged at a symmetrical tilt angle relative to the photoelectric sensor, so that the light emitted by them can be reflected and focused onto the photoelectric sensor after shining on the collecting tube.

5. The red blood cell spillage detection device as described in claim 4, characterized in that, Also includes: The housing, in which the first light source, the second light source, and the photoelectric sensor are all fixed; The circuit board is tightly attached to the bottom of the housing, and the circuit board is made of an opaque material; A light guide column, disposed inside the housing and corresponding to the photoelectric sensor, is used to guide reflected light to the photoelectric sensor; An elastic element is disposed inside the housing and connected to the light guide post, for applying an elastic force toward the collection tube to the light guide post, so that the light guide post is in close contact with the outer wall of the collection tube when in the detection state.

6. The red blood cell spillage detection device as described in claim 5, characterized in that, The housing is also provided with light guide columns corresponding to the first light source and the second light source, respectively, to guide the light emitted by them to the collection tube.

7. The red blood cell spillage detection device as described in claim 1, characterized in that, The controller includes: A digital-to-analog converter interface is used to output analog control signals to the light source module to adjust the driving current of the first light source and the second light source respectively; An analog-to-digital converter interface is used to receive and digitize the voltage signal output by the signal processing circuit. Furthermore, the controller is configured to execute an initialization calibration procedure, which includes: With the collection tube empty, the average intensity of the reflected light at the first wavelength and the average intensity of the reflected light at the second wavelength were obtained respectively. Calculate the initial ratio of the average intensity of reflected light at the first wavelength to the average intensity of reflected light at the second wavelength; The driving current of the first light source or the second light source is adjusted through the digital-to-analog conversion interface so that the initial ratio approaches a preset reference value.

8. The red blood cell spillage detection device as described in claim 7, characterized in that, The steps of obtaining the average value of the first wavelength reflected light intensity and the average value of the second wavelength reflected light intensity respectively when the collection tube is empty include: The light source is controlled to work at a preset frequency for N cycles. In each cycle, the reflected light intensity is measured when the light source is lit and when the light source is turned off. Calculate the average reflected light intensity during N cycles when the light is on and the average reflected light intensity when the light is off; Subtracting the average value when the light is on from the average value when the light is off gives the average value of the reflected light intensity after eliminating ambient light interference.

9. The red blood cell spillage detection device as described in claim 1, characterized in that, The first wavelength is red light, with a wavelength range of 700 to 710 nm; the second wavelength is green light, with a wavelength range of 540 to 550 nm.

10. The red blood cell spillage detection device as described in claim 1, characterized in that, The controller is also configured to: Calculate the ratio of the intensity of reflected light at the first wavelength to the intensity of reflected light at the second wavelength; The ratio is compared with a preset threshold. If the ratio exceeds the preset threshold, it is determined that red blood cell spillage has occurred, and an alarm signal is issued through the communication module.

11. A method for detecting red blood cell spillage, using the apparatus as described in any one of claims 1 to 10, characterized in that, Includes the following steps: The light source module emits light of the first and second wavelengths into the blood component collection tube; The first and second wavelengths of reflected light reflected back from the liquid inside the tube are received by a photoelectric sensor and converted into current signals. The current signal is amplified and filtered by a signal processing circuit to output a voltage signal that reflects the intensity of the reflected light. The controller receives and processes the voltage signal, and determines the red blood cell overflow status based on the ratio of the reflected light intensity of the first wavelength to the second wavelength.

12. The method for detecting red blood cell spillage as described in claim 11, characterized in that, The step of amplifying and filtering the current signal through a signal processing circuit to output a voltage signal reflecting the intensity of the reflected light includes: The current signal is converted into a first voltage signal through a first amplification stage; The DC component caused by ambient light in the first voltage signal is filtered out by the DC blocking element, while the AC component caused by the light source is retained. The AC component is amplified a second time by a second amplification stage to output a second voltage signal.

13. The method for detecting red blood cell spillage as described in claim 11, characterized in that, Before performing the red blood cell spill detection, an initialization and calibration step is also included: When the collection tube is empty, the average value of the reflected light intensity of the first wavelength and the average value of the reflected light intensity of the second wavelength are obtained by the controller. Calculate the initial ratio of the average intensity of reflected light at the first wavelength to the average intensity of reflected light at the second wavelength; By adjusting the driving current of the first or second light source, the initial ratio is made to approach a preset reference value.

14. The method for detecting red blood cell spillage as described in claim 13, characterized in that, The step of obtaining the average value of the first wavelength reflected light intensity and the average value of the second wavelength reflected light intensity through the controller when the collection tube is empty includes: The light source is controlled to work at a preset frequency for N cycles. In each cycle, the reflected light intensity is measured when the light source is lit and when the light source is turned off. Calculate the average reflected light intensity during N cycles when the light is on and the average reflected light intensity when the light is off; Subtract the average value when the light is on from the average value when the light is off to get the average value of the reflected light intensity after eliminating ambient light interference.

15. The method for detecting red blood cell spillage as described in claim 11, characterized in that, The step of determining the state of red blood cell overflow includes: Calculate the ratio of the intensity of reflected light at the first wavelength to the intensity of reflected light at the second wavelength; The ratio is compared with a preset threshold. If the ratio exceeds the preset threshold, it is determined that red blood cell overflow has occurred, and an alarm signal is issued.

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