Multi-channel wireless blood oxygen collecting and monitoring device and method

Abstract

The invention relates to the technical field of blood oxygen signal acquisition and monitoring, and provides a multi-channel wireless blood oxygen acquisition and monitoring device and a multi-channel wireless blood oxygen acquisition and monitoring method aiming at solving the problems that a wired data transmission mode is adopted to measure a blood oxygen signal in traditional single photoelectric blood oxygen concentration detection and the accuracy of acquired data is poor. A plurality of photoelectric detectors receive LED reflected light of different depths, blood oxygen signals are calculated according to the received reflected light and are output and displayed, the multi-wavelength LEDs avoid interference of melanin, water molecules and other components on the surface layer of the human brain, and the multi-channel photoelectric detectors are used for detecting oxyhemoglobin of different depths of the human brain and the change of the hemoglobin content. Monitoring data are more accurate and suitable for real-time dynamic monitoring of blood oxygen saturation signals and brain oxygen saturation signals of a patient clinically, a wireless transmission function is achieved, blood oxygen saturation of multiple parts such as the brain and fingertips can be monitored in real time, monitoring precision is high, stability is good, wearing is comfortable, and operation is easy and convenient.

Description

Technical Field

[0001] This invention relates to the field of blood oxygen signal acquisition and monitoring technology, specifically to a multi-channel wireless blood oxygen acquisition and monitoring device and method. Background Technology

[0002] Blood oxygen saturation and brain oxygen saturation are important vital signs in the human body and are important indicators for measuring the oxygen content in the blood. Data on blood oxygen saturation and brain oxygen saturation are obtained through the collection and monitoring of blood oxygen signals.

[0003] In recent years, the detection range and accuracy of pulse oximeters have been significantly improved. However, existing pulse oximeters still have significant shortcomings in the following aspects: most pulse oximeters can only measure the blood oxygen saturation of one finger, and cannot simultaneously monitor cerebral blood oxygenation or the blood oxygen saturation of different fingers. Single-channel measurement cannot reflect the differences in oxygenation status of different tissues in the human body, which limits the application of pulse oximeters in clinical and research applications; some pulse oximeters require wired connection to a monitor or data recording device, which is inconvenient in actual use; wired pulse oximeters have limitations in data transmission, and wireless transmission latency affects the synchronization of multiple devices, making it impossible to achieve remote real-time monitoring and data sharing; traditional cerebral blood oxygenation monitoring equipment uses a two-wavelength LED and two-channel photodiode scheme, which cannot remove data interference from the cerebral cortex; existing blood oxygenation detection methods also have shortcomings in data processing. Due to space constraints, some devices have poor processor data processing capabilities, and motion artifacts and ambient light interference cause data drift, affecting the accuracy and reliability of measurement results. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention aims to provide a multi-channel wireless blood oxygen acquisition and monitoring device and method, which is particularly suitable for real-time dynamic monitoring of patients' blood oxygen saturation signals and brain oxygen saturation signals in clinical practice. It has wireless transmission capabilities and can monitor blood oxygen saturation in multiple locations such as the brain and fingertips in real time. It has the advantages of high monitoring accuracy, good stability, comfortable wear, and simple operation.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A multi-channel wireless blood oxygen acquisition and monitoring device includes several fingertip blood oxygen signal acquisition terminals, one brain blood oxygen signal acquisition terminal, and a host for receiving and transmitting blood oxygen signals. The blood oxygen signal acquisition terminals and the host monitor blood oxygen signals in real time via 2.4G wireless communication. The host and several blood oxygen signal acquisition terminals adopt a master-slave polling mechanism for data acquisition and transmission. According to the preset polling order and rules, the host automatically sends query commands to each blood oxygen signal acquisition terminal in sequence, and displays the blood oxygen signal in the received response signal on the display screen.

[0006] Furthermore, the cerebral blood oxygenation signal acquisition terminal also includes a circuit board fixing assembly. The side of the circuit board fixing assembly that fits against the forehead is a concave arc structure, and the other side is a flat surface. The signal processing circuit of the cerebral blood oxygenation signal acquisition terminal is fixed on the flat surface, and the signal acquisition circuit of the cerebral blood oxygenation signal acquisition terminal is fixed on the arc structure. The signal processing circuit is connected to the signal acquisition circuit through a through hole on one side of the circuit board fixing assembly.

[0007] Furthermore, the circuit board fixing assembly also includes adjustable forehead straps at both ends for fixing the cerebral blood oxygen signal acquisition end.

[0008] Furthermore, the signal acquisition circuit includes several LEDs of different wavelengths and several photodetectors for receiving the reflected signals from the LEDs. All the LEDs are located at one end of the FPC board of the signal acquisition circuit, and the photodetectors are located at the other end of the FPC board of the signal acquisition circuit and are equidistantly distributed. A black silicone pad for eliminating ambient light interference is provided on the signal acquisition circuit, and several through holes are opened in the black silicone pad at the corresponding positions of the LEDs and photodetectors.

[0009] A multi-channel wireless blood oxygen acquisition and monitoring method, implemented using the aforementioned multi-channel wireless blood oxygen acquisition and monitoring device, utilizes LEDs of different wavelengths as light sources. Several photodetectors receive LED reflected light at different depths, calculate the blood oxygen signal based on the received reflected light, and output and display it. Specifically, it includes the following steps: Step a. The main control chip of the cerebral blood oxygen signal acquisition terminal outputs multiple PWM signals in a cyclical manner according to the preset timing and the number of LEDs to control the constant current source circuit to drive the LEDs, ensuring that the brightness of each LED is constant; single cycle T cycle The total duration is 10ms, and the timing distribution satisfies: High-level output time Dead time ; Step b. Under the action of the PWM signal, only one LED illuminates at a time. When each LED illuminates, the photodetector collects the light intensity signal of the current LED. The cycle period is a single cycle. T cycle ; Step c. Calculate the change in optical density based on the collected light intensity signal. ,in Let be the wavelengths of the incident light and the received light. r i This indicates the detection distance between the LED and the photodetector. For the incident light intensity, To receive light intensity; based on the extended modified Beer-Lambert equation, a model incorporating changes in hemoglobin concentration is constructed. Changes in oxyhemoglobin concentration melanin concentration and water content The system of equations; the coefficient matrix of the system of equations Extinction coefficients corresponding to each wavelength Differential path factor and detection range Calculated; Step d. Convert the system of equations from step c into matrix form. The coefficient matrix elements in Where k is the coefficient matrix A The row index corresponds to the measurement data of the k-th wavelength-distance combination, and the coefficient matrix. A Number of rows = Number of wavelengths × Number of distances For different indexes j for different wavelengths The extinction coefficient of LEDs, The parameter vector to be solved corresponds to the result of the detection index. , Let be the observed optical density vector, where each element is . .

[0010] Furthermore, by synchronously triggering the light intensity signal acquisition with the alternating emission sequence of LEDs of different wavelengths, ambient light noise and motion artifacts are suppressed; among them, the main control module of the blood oxygen signal acquisition end is in a single cycle T cycle The system collects signals from each LED multiple times and eliminates transient interference using a moving average algorithm.

[0011] Further steps In this process, based on the signal differences of all photodetectors, a set of equations is constructed, and the extended modified Beer-Lambert equation is as follows: Follow the steps Change in optical density The parameters are obtained by solving the equations simultaneously. , .

[0012] Furthermore, the change in brain oxygen saturation is as follows: .

[0013] In summary, compared with the prior art, the present invention has the following beneficial effects: This invention enables simultaneous acquisition and monitoring of blood oxygen saturation signals from multiple sites via multiple blood oxygen signal acquisition terminals connected to a host computer, resulting in more accurate blood oxygenation status. The invention utilizes 2.4G wireless transmission technology to monitor the patient's blood oxygen signal in real time, providing timely alarm prompts when abnormalities are detected. Furthermore, it employs multiple LEDs of different wavelengths to perform high-precision measurements of blood oxygen at multiple sites, ensuring the accuracy of the acquired and monitored data.

[0014] The blood oxygen signal acquisition terminals of this invention are all small in size and lightweight, making them easy to wear. Furthermore, each blood oxygen signal acquisition terminal is wirelessly connected, reducing the activity restrictions of the subject during the monitoring process. They also support connection and data sharing with other medical devices, which contributes to the future intelligence and informatization of medical devices.

[0015] The brain blood oxygenation signal acquisition terminal of this invention uses multi-wavelength LEDs to avoid interference from melanin, water molecules and other components on the surface of the human brain. It uses a multi-channel photodetector to detect changes in oxygenated hemoglobin and hemoglobin content at different depths of the human brain, making the monitoring data more accurate. The LEDs are driven by constant current, which can better achieve constant LED power and make the acquired data more stable. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the signal connection of the device of the present invention, wherein the host and each blood oxygen signal acquisition terminal use 2.4G wireless communication, and the host and mobile phone or computer host use Bluetooth communication; Figure 2 This is a flowchart of the host polling method of the present invention; Figure 3 This is a flowchart of the response process of each blood oxygen signal acquisition terminal in this invention; Figure 4 This is a block diagram of the host circuit. Figure 5 This is a block diagram of the circuit principle for the cerebral blood oxygenation signal acquisition terminal. Figure 6 This refers to the circuit block diagram of the blood oxygen signal acquisition terminal; Figure 7 This is a diagram of the circuit board mounting device for the brain blood oxygen signal acquisition terminal, which includes 660nm, 780nm, 850nm, and 940nm LEDs and three photodetectors. Figure 8 This is a diagram showing the relative positions of LEDs and photodetectors, including 660nm, 780nm, 850nm, and 940nm LEDs and three photodetectors. Figure 9 This is a timing diagram for driving four LEDs; Figure 10 This is a schematic diagram of an LED constant current drive circuit, a low-pass filter amplifier circuit, and a transimpedance amplifier.

[0017] Figure 11 This is a reflection path diagram of a photon in a homogeneous medium, where , h To detect depth, d The distance between the light source and the detector; Figure 12 This is a flowchart of the brain blood oxygen signal acquisition terminal.

[0018] In the figure, 1 is the PCB rigid board fixing surface, 2 is the FPC flexible board fixing surface, 3 is the top and bottom connecting groove for the FPC flexible board to pass through and connect to the PCB rigid board, 4 is the spring strap connecting groove, 5 is three photoelectric receivers, the distances between the three photoelectric receivers and the LEDs are 15mm, 22.5mm and 30mm respectively, and 6 is LEDs of different wavelengths, which in this embodiment are 660nm, 780nm, 850nm and 940nm LEDs respectively. Detailed Implementation

[0019] The present invention will now be further described with reference to the accompanying drawings.

[0020] like Figures 1-12 As shown, this invention discloses a multi-channel wireless blood oxygen acquisition and monitoring device, including several fingertip blood oxygen signal acquisition terminals, one brain blood oxygen signal acquisition terminal, and a host for receiving and transmitting blood oxygen signals. The blood oxygen signal acquisition terminals and the host monitor blood oxygen signals in real time via 2.4G wireless communication. The host and several blood oxygen signal acquisition terminals adopt a master-slave polling mechanism for data acquisition and transmission. According to the preset polling order and rules, the host automatically sends query commands to each blood oxygen signal acquisition terminal in sequence, and displays the blood oxygen signal in the received response signal on the display screen.

[0021] The cerebral oxygenation signal acquisition unit also includes a circuit board fixing assembly. One side of the assembly, which conforms to the forehead, is a concave, curved structure. This biomimetic curved structure adapts to the contours of the human forehead to support the FPC flexible circuit board. The other side is flat. The signal processing circuit of the cerebral oxygenation signal acquisition unit is fixed on the flat side, while the signal acquisition circuit is fixed on the curved structure. The signal processing circuit is connected to the signal acquisition circuit through a through-hole on one side of the circuit board fixing assembly. Both ends of the circuit board fixing assembly also include adjustable forehead straps for securing the cerebral oxygenation signal acquisition unit.

[0022] The signal acquisition circuit includes several LEDs of different wavelengths and several photodetectors for receiving the reflected signals from the LEDs. All the LEDs are located at one end of the FPC board of the signal acquisition circuit, and the photodetectors are located at the other end of the FPC board of the signal acquisition circuit and are equidistantly distributed. The signal acquisition circuit is provided with a black silicone pad for eliminating ambient light interference. The black silicone pad has several through holes at the corresponding positions of the LEDs and photodetectors.

[0023] The signal acquisition circuit includes several LEDs of different wavelengths and several photodetectors for receiving the reflected signals from the LEDs. All the LEDs are located at one end of the FPC board of the signal acquisition circuit, and the photodetectors are located at the other end of the FPC board and are equidistantly distributed. Figure 7 In the illustrated embodiment, all LEDs are positioned close to one end of the FPC board and their distribution direction is perpendicular to the distribution direction of the photodetectors. The distances between the multi-wavelength LEDs and the three photodetectors are 15mm, 22.5mm, and 30mm, respectively. A black silicone pad is provided on the signal acquisition circuit to eliminate ambient light interference. During use, the FPC board is attached to the forehead, and the gap between them is filled with the black silicone pad. Several through holes are opened in the black silicone pad at the corresponding positions of the LEDs and photodetectors. The four wavelength LEDs and three photodetectors are placed on the same circuit board, which is an FPC board. The multi-wavelength LEDs are placed at one end of the FPC board, the three photodetectors are placed in the middle of the FPC board, and the gold fingers of the flexible connector are placed at the other end. The multi-wavelength LEDs and three photodetectors are placed on the same side of the FPC board, and the gold fingers of the flexible connector are placed on the other side of the FPC board. The LEDs and photodetectors are distributed on the same side, and the gold fingers are on the other side. After the FPC board is connected to the PCB rigid board, the board bends, and the LEDs and photodetectors are more closely aligned with the head, reducing errors caused by ambient light. Placing the LED and photodetector on the same side of the FPC allows them to fit snugly against the forehead, while placing the flexible circuit board's gold fingers on the other side facilitates connection. This is related to the structure of the brain oxygen acquisition terminal, and setting different distances allows for the detection of different depths.

[0024] This invention also discloses a multi-channel wireless blood oxygen acquisition and monitoring method, implemented using the aforementioned multi-channel wireless blood oxygen acquisition and monitoring device. It utilizes LEDs of different wavelengths as light sources, and several photodetectors receive LED reflected light at different depths. The blood oxygen signal is calculated based on the received reflected light and then displayed. Specifically, the method includes the following steps: Step a. The main control chip of the cerebral blood oxygen signal acquisition terminal outputs multiple PWM signals in a cyclical manner according to the preset timing and the number of LEDs to control the constant current source circuit to drive the LEDs. The PWM signals drive the LEDs through the constant current source, and each PWM signal drives one LED through the constant current source, ensuring that the brightness of each LED is constant; single cycle T cycle The total duration is 10ms, and the timing distribution satisfies: The high-level output time Dead time ;exist Figure 7In the illustrated embodiment, four LEDs and three photodetectors are used. The main control chip controls the four wavelength LEDs to operate in the following timing sequence: First stage: The 660nm LED emits light for 1.8ms, during which the three photodiodes collect corresponding light intensity data; the LED then stops emitting light. Second stage: The 780nm LED emits light for 1.8ms, during which the three photodiodes collect corresponding light intensity data; the LED then stops emitting light. Third stage: The 850nm LED emits light for 1.8ms, during which the three photodiodes collect corresponding light intensity data; the LED then stops emitting light. Fourth stage: The 940nm LED emits light for 1.8ms, during which the three photodiodes collect corresponding light intensity data; the LED then stops emitting light. The cycle period is 10ms, and the emission periods of each wavelength do not overlap. The 660nm, 780nm, 850nm, and 940nm LEDs are used as input signals for brain blood oxygenation to monitor components such as melanin, hemoglobin, oxyhemoglobin, and water molecules. Three photodetectors collect brain region reflection signals. Transimpedance amplifiers and low-pass filters are used to perform hardware filtering and amplification of the blood oxygenation signal.

[0025] Step b. Under the action of multiple PWM signals, only one LED illuminates at a time. When each LED illuminates, the photodetector collects the light intensity signal of the current LED. The cycle period is a single cycle. T cycle ; Step c. Calculate the change in optical density based on the collected light intensity signal. ,in r i This indicates the detection distance between the LED and the photodetector. In this embodiment, , For the incident light intensity, To receive light intensity; based on the extended modified Beer-Lambert equation, a model incorporating changes in hemoglobin concentration is constructed. Changes in oxyhemoglobin concentration melanin concentration and water content The system of equations; the coefficient matrix of the system of equations Extinction coefficients corresponding to each wavelength Differential path factor and detection range Calculations show that different substances have different extinction coefficients for different wavelengths. The equations within the coefficient matrix are solved using the least squares method. Based on the signal differences of all photodetectors, an extended modified Beer-Lambert equation is constructed: The change in optical density in step c is the data value measured by the sensor. The absorption of these substances leads to the sensor's measurement result. The extended modified Beer-Lambert equation, combined with the formula in step c, forms the matrix equation A·c=b. (Following the steps...) Change in optical density The parameters are obtained by solving the equations simultaneously. , .

[0026] Step d. Convert the system of equations from step c into matrix form. The coefficient matrix elements in , For different indexes j for different wavelengths The extinction coefficient of LEDs, The parameter vector to be solved , Let be the observed optical density vector, where each element is . .

[0027] By synchronously triggering the light intensity signal acquisition with the alternating emission sequence of LEDs of different wavelengths, ambient light noise and motion artifacts are suppressed; among them, the main control module of the blood oxygen signal acquisition end is in a single cycle T cycle The system collects signals from each LED multiple times and eliminates transient interference using a moving average algorithm.

[0028] Total hemoglobin concentration and total oxyhemoglobin concentration: brain oxygen saturation .

[0029] in Figure 1 This is a schematic diagram of wireless communication between different components of the present invention. Each blood oxygen signal acquisition terminal only communicates with the host, while the host can communicate with all blood oxygen signal acquisition terminals. Figure 2 This is a flowchart of the polling communication mechanism of the present invention.

[0030] This invention utilizes photoplethysmography (PPG) to obtain blood oxygen saturation data at corresponding locations based on the different absorption coefficients of oxyhemoglobin and hemoglobin to LEDs of different wavelengths. When an artery pulsates, the volume of oxyhemoglobin and hemoglobin in the artery changes. The differences in photoelectric signals generated by different LEDs after reflection or transmission are used to acquire blood oxygen saturation data. The complete process of acquiring blood oxygen signals specifically includes the following steps: Step 1. When measuring, correctly wear the fingertip blood oxygen signal acquisition terminal and the brain blood oxygen signal acquisition terminal; the fingertip blood oxygen signal acquisition terminal should fit the fingertip with a curved surface; the brain blood oxygen signal acquisition terminal should fit the forehead with a concave curved surface to match the forehead contour, be fixed with an elastic band, and use a black silicone pad to eliminate light leakage.

[0031] Step 2. After wearing all the pulse oximetry signal acquisition terminals, turn on the pulse oximetry monitoring device. The system automatically detects the connection status of each acquisition terminal and establishes a link with the host through the 2.4GHz wireless communication module. Step 3. The multi-channel pulse oximetry monitoring system host starts working, polling the pulse oximetry signal in the following order: brain pulse oximetry signal acquisition terminal, fingertip pulse oximetry signal acquisition terminal 1, fingertip pulse oximetry signal acquisition terminal 2, fingertip pulse oximetry signal acquisition terminal 3, fingertip pulse oximetry signal acquisition terminal 4, fingertip pulse oximetry signal acquisition terminal 5, fingertip pulse oximetry signal acquisition terminal 6, fingertip pulse oximetry signal acquisition terminal 7, fingertip pulse oximetry signal acquisition terminal 8, fingertip pulse oximetry signal acquisition terminal 9, and fingertip pulse oximetry signal acquisition terminal 10.

[0032] Step 4. After each blood oxygen signal acquisition terminal receives the query command from the host, it sends the current blood oxygen signal to the host.

[0033] Step 5. After the host receives the data sent by the queried slave, it processes and calculates the data and displays it on the screen.

[0034] Step 6. After the host computer processes and displays the blood oxygen signal for that area, it queries the next blood oxygen signal acquisition terminal for the blood oxygen signal. exist Figure 1 and Figure 2 In this embodiment, the host actively polls the blood oxygen signal in the order of the brain blood oxygen signal acquisition terminal and the 10 fingertip blood oxygen signal acquisition terminals. When each blood oxygen signal acquisition terminal receives the query signal from the host, it sends the blood oxygen signal it has acquired to the host. After being processed by the host, the signal is displayed on the display.

[0035] See Figure 3 The diagram shows the circuit principle of the main unit of this invention. The entire unit is powered by a 5V DC voltage, which is reduced to 3.3V by an AMS1117 voltage regulator chip to power the microcontroller, display and 2.4G wireless communication module.

[0036] The fingertip oxygenation signal acquisition unit uses alternating flashes of 660nm red LEDs and 940nm infrared LEDs as input signals for fingertip oxygenation. When the two wavelengths of light shine on the finger, they are absorbed by hemoglobin and oxyhemoglobin. Some of the unabsorbed light is reflected back. By collecting the corresponding light intensities of the two wavelengths, the content of the two proteins can be reflected. A photodetector is used to collect the reflected signals after the arterial hemoglobin and oxyhemoglobin in the fingertip absorb light of different wavelengths. Transimpedance amplifiers, differential amplifiers, filters and other circuits are used to perform hardware filtering and amplification of the blood oxygenation signal. The fingertip oxygenation signal acquisition unit contacts the fingertip, and its contact surface is curved to fit the fingertip, with a black silicone pad filling the gap between the two.

[0037] See Figure 4 This is a block diagram of the circuit principle of the fingertip blood oxygen signal acquisition terminal of the present invention. The host of the multi-channel wireless blood oxygen monitoring device is powered by a 5V DC power supply. An STM32H743IIT6 microcontroller is used as the main control MCU. The main control MCU is connected to a 2.4G wireless communication module through a serial port. The lithium battery is charged through a TYPE-C interface via a lithium battery management chip. After the lithium battery is charged, the voltage of the lithium battery is reduced to 3.3V by an AMS1117 voltage regulator chip to power the main control MCU STM32F103C8T6, the photoelectric signal acquisition circuit, and the 2.4G wireless communication module. The microcontroller drives a 660nm and a 900nm LED to blink alternately by outputting two PWM waves. It also collects the analog signal of a photodiode after passing through a transimpedance amplifier, a differential amplifier, and a filter through an ADC. When the main control MCU receives the query signal from the host through the 2.4G wireless communication module, it sends the acquired blood oxygen signal to the host through the 2.4G wireless communication module.

[0038] See Figure 5 This is a block diagram of the cerebral blood oxygen signal acquisition circuit of the present invention. A TYPE-C interface is used to charge the lithium battery via a lithium battery management chip. After charging, the lithium battery voltage is reduced to 3.3V by an AMS1117 voltage regulator chip to power the main control microcontroller STM32F103C8T6, the photoelectric signal acquisition circuit, and the 2.4G wireless communication module. The microcontroller drives 660nm, 780nm, 850nm, and 940nm LEDs to blink alternately through four PWM time-division multiplexing outputs. The analog signals from the three photodiodes are acquired via an ADC, passing through a transimpedance amplifier and a low-pass filter. When the main control microcontroller receives an interrogation signal from the host via the 2.4G wireless communication module, it transmits the acquired blood oxygen signal to the host via the 2.4G wireless communication module. The device of the present invention is equipped with a Bluetooth module. When connected to a mobile phone or computer host, it transmits the blood oxygen signal to the Bluetooth device via Bluetooth.

[0039] See Figure 12 The cerebral oxygenation acquisition unit uses a main control chip to control PWM output to drive four wavelength light sources: 660nm, 780nm, 850nm, and 940nm. The LEDs are driven by a constant current to ensure constant brightness. The total duration of a single cycle is 10ms, and the timing distribution meets the following requirements: High-level output time Dead time Simultaneously, light intensity data at three different detection distances after light is absorbed and reflected by human brain tissue are collected. This data is then processed by a transimpedance amplifier and a low-pass filter before being acquired by the main control chip via an ADC, which calculates the change in optical density. in .

[0040] Based on the extended modified Beer–Lambert equation, a model incorporating changes in hemoglobin concentration is constructed. Changes in oxyhemoglobin concentration melanin concentration and water content The system of equations, the coefficient matrix of the system of equations The extinction coefficient corresponding to each wavelength ( ), Differential path factor and detection range Calculated. Convert the system of equations into matrix form. The coefficient matrix Its dimensions are 12×4. ( The wavelength of the current row. This represents the detection distance for the current row. wavelength The following parameters (extinction coefficient) The parameter vector to be solved , Let be the observed optical density vector, where each element is . .

[0041] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A multi-channel wireless blood oxygen acquisition and monitoring device, characterized in that, It includes several fingertip blood oxygen signal acquisition terminals, one brain blood oxygen signal acquisition terminal, and a host for receiving and transmitting blood oxygen signals. The blood oxygen signal acquisition terminals and the host monitor blood oxygen signals in real time via 2.4G wireless communication. The host and several blood oxygen signal acquisition terminals adopt a master-slave polling mechanism for data acquisition and transmission. According to the preset polling order and rules, it automatically sends query commands to each blood oxygen signal acquisition terminal in sequence, and displays the blood oxygen signal in the received response signal on the display screen.

2. The multi-channel wireless blood oxygen acquisition and monitoring device according to claim 1, characterized in that, The cerebral blood oxygenation signal acquisition terminal also includes a circuit board fixing assembly. The side of the circuit board fixing assembly that fits against the forehead is a concave arc structure, and the other side is a flat surface. The signal processing circuit of the cerebral blood oxygenation signal acquisition terminal is fixed on the flat surface, and the signal acquisition circuit of the cerebral blood oxygenation signal acquisition terminal is fixed on the arc structure. The signal processing circuit is connected to the signal acquisition circuit through a through hole on one side of the circuit board fixing assembly.

3. The multi-channel wireless blood oxygen acquisition and monitoring device according to claim 2, characterized in that, The circuit board fixing assembly also includes adjustable forehead straps at both ends for fixing the cerebral blood oxygen signal acquisition end.

4. The multi-channel wireless blood oxygen acquisition and monitoring device according to claim 2, characterized in that, The signal acquisition circuit includes several LEDs of different wavelengths and several photodetectors for receiving the reflected signals from the LEDs. All the LEDs are located at one end of the FPC board of the signal acquisition circuit, and the photodetectors are located at the other end of the FPC board of the signal acquisition circuit and are equidistantly distributed. A black silicone pad for eliminating ambient light interference is provided on the signal acquisition circuit. Several through holes are opened in the black silicone pad at the corresponding positions of the LEDs and photodetectors.

5. A multi-channel wireless blood oxygen acquisition and monitoring method, implemented using the multi-channel wireless blood oxygen acquisition and monitoring device according to any one of claims 1 to 4, characterized in that: Using LEDs of different wavelengths as a light source, several photodetectors receive LED reflected light at different depths. The blood oxygen signal is calculated based on the received reflected light and displayed. The specific steps include: Step a. The main control chip of the cerebral blood oxygen signal acquisition terminal outputs multiple PWM signals in a cyclical manner according to the preset timing and the number of LEDs to control the constant current source circuit to drive the LEDs, ensuring that the brightness of each LED is constant; single cycle T cycle The total duration is 10ms, and the timing distribution satisfies: High-level output time Dead time ; Step b. Under the action of the PWM signal, only one LED illuminates at a time. When each LED illuminates, the photodetector collects the light intensity signal of the current LED. The cycle period is a single cycle. T cycle ; Step c. Calculate the change in optical density based on the collected light intensity signal. ,in Let be the wavelengths of the incident light and the received light. r i This indicates the detection distance between the LED and the photodetector. For the incident light intensity, To receive light intensity; based on the extended modified Beer-Lambert equation, a model incorporating changes in hemoglobin concentration is constructed. Changes in oxyhemoglobin concentration melanin concentration and water content The system of equations; the coefficient matrix of the system of equations Extinction coefficients corresponding to each wavelength Differential path factor and detection range Calculated; Step d. Convert the system of equations from step c into matrix form. The coefficient matrix elements in Where k is the coefficient matrix A The row index corresponds to the measurement data of the k-th wavelength-distance combination, and the coefficient matrix. A Number of rows = Number of wavelengths × Number of distances For different indexes j for different wavelengths The extinction coefficient of LEDs, The parameter vector to be solved corresponds to the result of the detection index. , Let be the observed optical density vector, where each element is . .

6. The multi-channel wireless blood oxygen acquisition and monitoring method according to claim 5, characterized in that: By synchronously triggering the light intensity signal acquisition with the alternating emission sequence of LEDs of different wavelengths, ambient light noise and motion artifacts are suppressed; among them, the main control module of the blood oxygen signal acquisition end is in a single cycle T cycle The system collects signals from each LED multiple times and eliminates transient interference using a moving average algorithm.

7. The multi-channel wireless blood oxygen acquisition and monitoring method according to claim 5, characterized in that, The steps In this process, based on the signal differences of all photodetectors, a set of equations is constructed, and the extended modified Beer-Lambert equation is as follows: Follow the steps Change in optical density The parameters are obtained by solving the equations simultaneously. , .

8. The multi-channel wireless blood oxygen acquisition and monitoring method according to claim 7, characterized in that: The change in brain oxygen saturation is: 。

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