CN113171087A

CN113171087A - Noninvasive cerebral blood oxygen monitoring device

Info

Publication number: CN113171087A
Application number: CN202110454462.0A
Authority: CN
Inventors: 季忠; 孙长龙; 钟文韬
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2021-04-26
Filing date: 2021-04-26
Publication date: 2021-07-27

Abstract

The invention discloses a brain blood oxygen non-invasive monitoring device, which comprises a brain blood oxygen information acquisition probe, a non-invasive acquisition subsystem and a monitoring processing subsystem, wherein an area of a human head corresponding to a forehead lobe is used as a brain blood oxygen non-invasive monitoring area, the absorption condition of the brain blood oxygen non-invasive monitoring area to red light is collected as a characteristic value of interference signals to human head tissues, the absorption conditions of the brain blood oxygen non-invasive monitoring area to infrared light with two different wavelengths are respectively collected as characteristic values of brain oxygenated hemoglobin concentration and brain reduced hemoglobin concentration, the brain oxygenated hemoglobin concentration value and the brain reduced hemoglobin concentration value which do not contain the interference signals to the human head tissues are further processed, and continuous real-time monitoring of the brain blood oxygen value can be stably and accurately realized. The invention provides a new solution for the noninvasive monitoring of cerebral blood oxygen, improves the stability and the accuracy of the noninvasive monitoring of cerebral blood oxygen, and is more favorable for promoting the clinical application of the noninvasive monitoring of cerebral blood oxygen.

Description

Noninvasive cerebral blood oxygen monitoring device

Technical Field

The invention relates to the technical field of biomedical signal acquisition and processing, in particular to a cerebral blood oxygen noninvasive monitoring device.

Background

Oxygen is an important substance for maintaining the metabolism of the human body. Hypoxia in human tissues is a significant cause of some diseases, and can even have serious consequences, which directly endanger life. The blood oxygen saturation of human tissues is an important parameter reflecting the oxygen supply of the tissues, and has extremely important clinical value.

The brain tissue has high metabolism rate, oxygen consumption accounts for 20% of total oxygen consumption, and the brain tissue is particularly sensitive to oxygen deficiency, and the short-time oxygen deficiency can cause unrecoverable damage to a central system. In cardiovascular operations of deep hypothermia for circulatory arrest, intravascular operations of neurosurgery, emergency treatment of brain accidents, rescue of critically ill patients, treatment of cerebral resuscitation after cardiac arrest, and the like, brain protection is an important issue. In order to avoid serious disorder of patients caused by hypoxia or ischemia and reduce the occurrence of surgical complications, the blood oxygen content of the brain needs to be continuously monitored, the conditions of brain oxygen supply and brain metabolism are closely concerned, and the oxygen quantity transmitted to the brain is timely optimized to prevent damage to the brain.

The conventional clinical method for obtaining the cerebral oxygen supply condition mainly comprises electroencephalogram measurement, somatosensory evoked potential measurement, jugular vein blood oxygen saturation measurement and transcranial Doppler measurement of the blood flow velocity of arterioles in the brain. However, these methods have some insurmountable problems. They are invasive or extremely complex to perform and the results obtained are difficult to interpret, above all because of the presence of too many false negative and false positive results, making these methods unreliable. Nuclear Magnetic Resonance (NMR) and Positron Emission Tomography (PET) reliably reflect brain oxygen supply, but they do not enable intraoperative real-time monitoring and are expensive in equipment.

The near infrared spectroscopy method for monitoring the brain oxygen supply condition is a very promising technology developed in recent years, provides a portable, real-time, continuous, simple-operation and relatively-cheap noninvasive measuring method for clinic, can be widely used for various occasions of brain oxygen monitoring, and obtains a brain blood oxygen saturation value easy for clinical explanation.

The near infrared spectroscopy measurement of blood oxygen saturation is based on The Lambert-Beer Law and The light scattering theory, and is performed by using The difference in The light absorption coefficients of reduced hemoglobin and oxygenated hemoglobin. Lambert-beer law is:

wherein A is the absorbance and I isIntensity of incident light, I_oTo emit light intensity, mu_aIs the absorption coefficient of the medium, d is the path of light through the medium, e is the molecular extinction coefficient, and c is the concentration of the medium.

In biological tissue spectroscopy, Optical Density (OD) is often used to describe the energy loss of light as it propagates through biological tissue, and the variation of the Optical Density is usually taken as the object of study. The absorbance is defined as:

if path d is constant, the optical density OD is proportional to the concentration c of the substance. In the red spectral region (622 nm-760 nm), HbO₂The absorption coefficient difference from HbR is large, and the shorter the wavelength is, the stronger the absorption capability of HbR to light is. When the wavelength of light gradually increases and enters an infrared spectrum region (780 nm-1 mm), the absorption coefficients of the two occur alternately leading, wherein the interval around 805nm (usually 800 nm-820 nm) is equal absorption points of hemoglobin (oxyhemoglobin and reduced hemoglobin). Since oxyhemoglobin and reduced hemoglobin have their own unique absorption spectra in the red and infrared regions, the relative percentage of each component, i.e., the blood oxygen saturation, can be determined.

Light in the above-mentioned spectral range has a strong penetration ability into the human body, and can penetrate several centimeters deep into the scalp, skull, and brain tissue. Each 100 g of tissue in the human brain contains 600-1000 mg of hemoglobin, so the human brain is an organ which is very suitable for infrared spectrum measurement of hemoglobin and oxygenated hemoglobin. The artery and the vein in the brain tissue are staggered, the vein accounts for 75 percent, the artery accounts for 20 percent, the capillary vessel accounts for 5 percent, and the blood oxygen saturation essence of the brain is the mixed oxygen saturation of local cerebral hemoglobin, and mainly represents the vein part. Because the blood oxygen saturation of the brain is mainly measured by the venous signals, the blood oxygen saturation monitoring device can be used without limitation under the conditions of low blood pressure, weakened pulse pulsation and even heart stop pulsation, can be applied to various occasions for monitoring the supply and demand conditions of the brain oxygen, and has limited effect on the pulse oximeter which is widely used clinically at present under the occasions.

In the method of measuring pulse oximetry, an important concept is: when light passes through vascular tissue, the transmitted light is divided into two parts: one part is the stable or direct current component (DC) which mainly reflects the absorption of various tissues in the non-pulsating part (such as muscle, bone, pigment, fat, venous blood, etc.), and the other part is the pulsating or alternating current part (AC) which mainly reflects the absorption of arterial blood. Since the detected pulse wave is entirely generated by arterial blood, the arterial blood oxygen saturation can be inferred from the transmission change of red light and infrared light. The brain blood oxygen measuring device and the pulse oximeter have different measuring purposes and measuring means and different measuring conditions. The principle of the pulse oximeter shows that the pulse oximeter can work only under the condition of arterial pulsation, so the cerebral oximeter has a special clinical application field and cannot be replaced by the pulse oximeter.

Much research has been done abroad on the technology for monitoring the brain blood oxygen by using the near infrared spectrum, the related technology is mature, and corresponding products are used clinically. In the prior art, the content of oxyhemoglobin and deoxyhemoglobin is obtained by utilizing the difference of the absorptivity of deoxyhemoglobin and oxyhemoglobin to light with different wavelengths of 600-900nm according to the Lambert-beer law, so as to obtain blood oxygen data of a brain region. Foreign cerebral blood oxygen equipments are represented by ETG4000-ETG7000 series systems of Hitachi, FOIRE3000 system of Shimadzu, CW5-CW6 series systems of Techen, USA, and CAS systems, and have been used in departments such as anesthesia department, neurosurgery, thoracic surgery, and monitoring room of hospitals. Most foreign cerebral blood oxygen equipment is large in size and complex to use, and has quite high requirements on operation of instruments and wearing of patient electrodes and quite high requirements on professional knowledge of users. Meanwhile, the high price of the instrument also has certain limitation on the purchase of hospitals, the diagnosis and treatment cost of patients is the height of the water rising boat, and the popularity of the cerebral blood oxygen monitoring equipment is greatly limited. In recent years, small portable cerebral blood oxygen monitoring equipment is developed abroad, but the small portable cerebral blood oxygen monitoring equipment still has the common problems of high price, high introduction cost and the like.

The development of the brain blood oxygen monitoring technology in China is always in a lagging status, but the development is struggled for the years. The research papers of the brain local blood oxygen monitoring device based on near infrared light are published in Qinghua university, Huazhong university of science and technology, Nanjing aerospace university and the like. Domestic medical instrument production enterprises are also beginning to pay attention to the research of cerebral blood oxygen monitoring technology. The Wuhan Yihai digital engineering Limited company introduced ES-5002, ES-5006 dual-wavelength cerebral blood oxygen monitor in 2009; the MNIR-P100 brain blood oxygen noninvasive monitor was introduced by Chongqing Ming xi medical instruments Inc. in 2015; the portable brain blood oxygen noninvasive monitor and the wearable wireless brain blood oxygen headband which are noninvasive, multichannel and real-time monitored are researched and developed by the Kobe-Bioseal technology Limited company in 2019 based on the NIRS principle and combined with the technology accumulated by the research center of the brain network group of the institute of Automation of the Chinese academy of sciences in the aspects of brain structure and optical characteristics. However, as can be seen from the inquiry of the website of the national drug administration, there are very few cerebral blood oxygen non-invasive monitoring products currently acquiring the registration certificate of medical equipment products in China, and only cerebral blood oxygen non-invasive monitors of Chongqing Ming xi medical equipment Limited company and Hebei Jinkangan medical equipment Limited company exist, but the cerebral blood oxygen product registration certificate of Wuhan Yihai digital engineering Limited company has not seen the information of continuous registration after the expiration. Clinical application effect survey also shows that the current domestic cerebral blood oxygen noninvasive monitoring equipment does not completely meet the clinical application requirements.

Disclosure of Invention

Aiming at the defects in the prior art, the technical problem to be solved by the invention is how to provide a brain blood oxygen non-invasive monitoring device scheme, so as to improve the stability and accuracy of the brain blood oxygen non-invasive monitoring, and provide new technical support and guarantee for continuous long-time acquisition and monitoring of clinical brain blood oxygen.

In order to solve the technical problems, the invention adopts the following technical scheme:

a brain blood oxygen non-invasive monitoring device comprises a brain blood oxygen information acquisition probe, a non-invasive acquisition subsystem and a monitoring processing subsystem;

the brain blood oxygen information acquisition probe is used for acting on an area of the head of a human body corresponding to the forehead of the brain and serving as a brain blood oxygen non-invasive monitoring area to acquire the photoelectric information of the brain blood oxygen; the acquired brain blood oxygen photoelectric information comprises: collecting the absorption condition of the brain blood oxygen non-invasive monitoring area on red light as a characteristic value of interference signals on human head tissues, collecting the absorption conditions of the brain blood oxygen non-invasive monitoring area on infrared light with two different wavelengths as a characteristic value of the concentration of local oxygenated hemoglobin in a prefrontal area and the concentration of local reduced hemoglobin in the prefrontal area, and collecting the absorption condition of the brain blood oxygen non-invasive monitoring area on infrared light with the wavelengths of absorption points such as hemoglobin and the like as a characteristic value of an individual difference correction factor;

the non-invasive acquisition subsystem is used for carrying out brain blood oxygen photoelectric information acquisition control on the brain blood oxygen information acquisition probe and transmitting the acquired brain blood oxygen photoelectric information to the monitoring processing subsystem;

the monitoring processing subsystem is used for carrying out cerebral blood oxygen monitoring analysis processing on the cerebral blood oxygen photoelectric information, respectively obtaining a local oxyhemoglobin concentration value of a prefrontal lobe area and a local reduced hemoglobin concentration value of the prefrontal lobe area, from which human head tissue interference signals are removed, so as to calculate and obtain a local blood oxygen saturation monitoring value of the prefrontal lobe area from which the human head tissue interference signals are removed, and further carrying out individual difference correction on the local blood oxygen saturation monitoring value of the prefrontal lobe area by using the individual difference correction factor to obtain cerebral blood oxygen non-invasive monitoring result data.

In the above noninvasive cerebral blood oxygen monitoring device, as a preferred scheme, the cerebral blood oxygen information collecting probe includes a flexible adhesive patch and a collecting probe connector;

one surface of the soft sticky material patch is used as a joint part which is jointed on the head of a human body in a region corresponding to the forehead of the brain, and the other surface and the peripheral part of the soft sticky material patch are shielded by a soft shading shell and used for reducing the light interference of ambient light to the joint part; one surface of the soft sticky material patch serving as the attaching part is provided with a red light source with the luminous wavelength of 680 nm-700 nm, a first infrared light source with the luminous wavelength of 760 nm-790 nm, a second infrared light source with the luminous wavelength of 840 nm-900 nm, a third infrared light source with the luminous wavelength of 800 nm-820 nm and two photodetectors which are arranged at intervals; the method comprises the following steps of detecting the difference value of the emergent light intensity of red light reflected by a red light source irradiating a cerebral blood oxygen non-invasive monitoring area through two photodetectors as a characteristic value of interference signals on human head tissues, detecting the difference value of the emergent light intensity of infrared light reflected by a first infrared light source irradiating the cerebral blood oxygen non-invasive monitoring area through the two photodetectors as a characteristic value of local reduced hemoglobin concentration of a prefrontal lobe area, detecting the difference value of the emergent light intensity of infrared light reflected by a second infrared light source irradiating the cerebral blood oxygen non-invasive monitoring area through the two photodetectors as a characteristic value of local oxygenated hemoglobin concentration of the prefrontal lobe area, and detecting the difference value of the emergent light intensity of infrared light reflected by a third infrared light source irradiating the cerebral blood oxygen non-invasive monitoring area through the two photodetectors as a characteristic value of an individual difference correction factor;

the power supply ends of the red light source, the first infrared light source, the second infrared light source and the third infrared light source and the signal output ends of the two photoelectric detectors are electrically connected with the collected signal output connector through cables.

In the above noninvasive cerebral blood oxygen monitoring device, as a preferred scheme, the red light source, the first infrared light source, the second infrared light source and the third infrared light source in the cerebral blood oxygen information collecting probe are closely arranged and integrated to form a multi-light-source patch lamp set; the arrangement distance between a first photoelectric detector in the two photoelectric detectors and the multi-light-source patch lamp group is 15-25 mm, and the arrangement distance between a second photoelectric detector and the multi-light-source patch lamp group is twice of the arrangement distance between the first photoelectric detector and the multi-light-source patch lamp group.

In the above-mentioned cerebral blood oxygen non-invasive monitoring device, as a preferred scheme, the non-invasive collection subsystem includes a collection probe interface for making electrical signal connection with the cerebral blood oxygen information collection probe, a signal preprocessing circuit for making signal conversion and filtering amplification preprocessing on the collected cerebral blood oxygen photoelectric information, a light source driving circuit for making light source driving on the cerebral blood oxygen information collection probe, a microcontroller for executing cerebral blood oxygen photoelectric information collection control and data transmission control, and a collection communication module for making data communication transmission with the monitoring processing subsystem; microcontroller carries out data transmission with gathering communication module and is connected, and carry out the electricity through light source drive circuit and signal preprocessing circuit and gather probe interface and be connected, be used for through the signal connection between gathering probe interface and the cerebral blood oxygen information acquisition probe, control light source drive circuit drive cerebral blood oxygen information acquisition probe carries out the collection of cerebral blood oxygen photoelectric information, and the cerebral blood oxygen photoelectric information who gathers transmits to microcontroller through signal preprocessing circuit and realizes the control of cerebral blood oxygen photoelectric information acquisition, microcontroller still is used for transmitting the cerebral blood oxygen photoelectric information who gathers to the monitoring processing subsystem through gathering communication module.

In the above noninvasive cerebral blood oxygen monitoring device, as a preferred scheme, the light source driving circuit is a constant current source driving circuit, a current output end of the light source driving circuit is electrically connected with a red light source, a first infrared light source, a second infrared light source and a third infrared light source in the cerebral blood oxygen information acquisition probe through an acquisition probe interface, and an enable control end of the light source driving circuit is electrically connected with the microcontroller;

the microcontroller outputs PWM signals through an I/O pin to control the light source driving circuit to drive the red light source, the first infrared light source, the second infrared light source and the third infrared light source in the brain blood oxygen information acquisition probe to emit light.

In the above-mentioned cerebral blood oxygen non-invasive monitoring device, as a preferred scheme, the microcontroller controls the light source driving circuit to drive the red light source, the first infrared light source, the second infrared light source and the third infrared light source in the cerebral blood oxygen information collecting probe to alternately emit light through a time-sharing interval, so that the photoelectric detector in the cerebral blood oxygen information collecting probe can detect the intensity of emergent light reflected by the cerebral blood oxygen non-invasive monitoring area irradiated by different light sources at different time intervals.

In the above-mentioned noninvasive cerebral blood oxygen monitoring device, as a preferred embodiment, the signal preprocessing circuit includes a current-voltage conversion circuit unit, a primary blocking circuit unit, a primary low-pass filter circuit unit, a primary amplifying circuit unit, a secondary low-pass filter circuit unit, a secondary amplifying circuit unit, a secondary blocking circuit unit, and a voltage-raising circuit unit, which are electrically connected in sequence;

the current-voltage conversion circuit unit is used for converting current signals of a photoelectric detector in the cerebral blood oxygen information acquisition probe into voltage signals;

the primary blocking circuit unit is used for carrying out primary direct current signal filtering processing on the voltage signal;

the primary low-pass filter circuit unit is a 10Hz low-pass filter circuit and is used for filtering interference signals above 10 Hz;

the primary amplifying circuit unit is used for carrying out primary amplifying processing on the voltage signal, and the amplification factor is 30-40 times;

the second-stage low-pass filter circuit unit is also a 10Hz low-pass filter circuit and is used for filtering interference signals above 10 Hz;

the secondary amplification circuit unit is used for carrying out secondary amplification processing on the voltage signal, and the amplification factor is 10-15 times;

the secondary DC blocking circuit unit is used for carrying out secondary DC signal filtering processing on the voltage signal;

the voltage boosting circuit unit is used for boosting the voltage signal to reach the voltage acquisition range of the microcontroller.

In the above-mentioned noninvasive cerebral blood oxygen monitoring device, as a preferred scheme, the monitoring processing subsystem includes a monitoring communication module for performing data communication transmission with the noninvasive acquisition subsystem, a monitoring processor for performing cerebral blood oxygen monitoring analysis on the cerebral blood oxygen photoelectric information, a data storage module for performing data storage, and a display module for performing data display of the noninvasive cerebral blood oxygen monitoring result; the monitoring communication module is used for acquiring the cerebral blood oxygen photoelectric information acquired by the non-invasive acquisition subsystem through the monitoring communication module, respectively calculating a local oxyhemoglobin concentration value of a prefrontal lobe area and a local reduced hemoglobin concentration value of the prefrontal lobe area, which are used for removing human head tissue interference signals, so as to calculate and obtain a local blood oxygen saturation monitoring value of the prefrontal lobe area, from which the human head tissue interference signals are removed, and further performing individual difference correction on the local blood oxygen saturation monitoring value of the prefrontal lobe area by using the individual difference correction factor, so that cerebral blood oxygen non-invasive monitoring result data is obtained, and the display module is controlled to display the data.

In the above-mentioned cerebral blood oxygen noninvasive monitoring device, as a preferred scheme, the noninvasive acquisition subsystem and the monitoring processing subsystem are integrated into a noninvasive monitoring all-in-one machine;

the non-invasive monitoring all-in-one machine comprises a machine case shell, wherein a display panel arrangement space close to the operation surface of the shell, a battery arrangement space close to the upper part of the back of the shell and an integrated circuit arrangement space close to the lower part of the back of the shell are arranged in the shell; the operating surface of the case shell is provided with a display window at a position corresponding to the arrangement space of the display panel, and the back surface or the side surface of the lower part of the case shell is provided with an interface mounting hole and a charging port mounting hole at a position corresponding to the arrangement space of the integrated circuit;

a battery is arranged in a battery arrangement space of the case shell and used for supplying power to each device of the noninvasive acquisition subsystem and the monitoring processing subsystem; an acquisition probe interface in the non-invasive acquisition subsystem is arranged at an interface mounting hole of a chassis shell; the display module in the monitoring processing subsystem is arranged in a display panel arrangement space of the case shell, and the display surface of the display module is arranged opposite to the display window on the case shell; an integrated circuit board is installed in an integrated circuit arrangement space of the case shell, a signal preprocessing circuit, a light source driving circuit, a microcontroller and an acquisition communication module in the non-invasive acquisition subsystem and a monitoring communication module, a monitoring processor and a data storage module in the monitoring processing subsystem are integrated on the integrated circuit board, and a power supply control circuit and a charging control circuit which are electrically connected with a battery are further integrated on the integrated circuit board; the power supply control circuit is a power supply connection circuit for supplying power to each device of the noninvasive acquisition subsystem and the monitoring processing subsystem by a battery, and a power supply switch is connected in the power supply control circuit and is arranged on the outer surface of the chassis shell; the charging interface is further installed at the position of the charging interface installation hole of the case shell and electrically connected to the battery through the charging control circuit, and is used for being connected to a power supply and charging the battery through the charging control circuit.

In the above noninvasive monitoring device for cerebral blood oxygen, as a preferred scheme, the top of the housing is further provided with a suspension bracket.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention discloses a noninvasive monitoring device for the blood oxygen saturation of partial tissues of human brain based on the different absorption degrees of oxyhemoglobin and deoxyhemoglobin to near infrared light, which comprises a brain blood oxygen information acquisition probe, a noninvasive acquisition subsystem and a monitoring processing subsystem, wherein the region of the head corresponding to the prefrontal lobe of the brain is used as a brain blood oxygen noninvasive monitoring region, the absorption condition of the brain blood oxygen noninvasive monitoring region to red light is used as the characteristic value of interference signals to the head tissues of the human body, the absorption conditions of the brain blood oxygen noninvasive monitoring region to two infrared lights with different wavelengths are respectively used as the characteristic values of the oxyhemoglobin concentration and the brain reducthemoglobin concentration of the brain, so as to obtain the surface interference signals and the deep useful signals of the brain blood oxygen noninvasive monitoring region, and further process to obtain the brain oxyhemoglobin concentration value and the brain reducthemoglobin concentration value which do not contain the interference signals of the head tissues of the human body, and realizing noninvasive monitoring of cerebral blood oxygen. The device can not cause the injury to the human body, and can be stable, accurate realization to the continuous real-time supervision of brain blood oxygen value.

2. The brain blood oxygen information acquisition probe which is designed autonomously and has four-wavelength photoelectric signal acquisition is adopted, so that the interference signals in the skin tissues of a test area are detected while the oxygenated hemoglobin and the reduced hemoglobin in the local tissues of the brain are detected, and in addition, near infrared light with one wavelength is added in consideration of individual difference and is used for calculating a correction factor; in addition, the brain blood oxygen information acquisition probe adopts the mode of pegging graft to improve convenience and interference immunity of brain blood oxygen device, be convenient for the change of brain blood oxygen noninvasive monitoring sensing probe, reduce the replacement cost of brain blood oxygen information acquisition probe.

3. According to the cerebral blood oxygen noninvasive monitoring device, the monitoring area selects the area of the human head corresponding to the forehead of the brain without dense hair coverage, so that the interference is reduced, near infrared light can smoothly penetrate extracranial tissues to enter the brain tissues, and the information containing the deep cerebral tissue blood oxygen saturation is obtained; in addition, the influence of melanin in human tissues is considered, the red light absorption condition is used as the representation of melanin interference signals of human head tissues, surface interference signals and deep useful signals are detected respectively, the acquired signal content is richer, the brain blood oxygen signals with high signal-to-noise ratio are obtained through convenient processing, and then the brain blood oxygen saturation monitoring value for removing the human head tissue interference signals is obtained, so that the brain blood oxygen continuous monitoring stability is better, and the monitoring precision is higher.

4. The design of the cerebral blood oxygen non-invasive monitoring device can be researched and developed based on an embedded technology, so that the hardware cost and the development cost of the product are greatly reduced, the price of the cerebral blood oxygen non-invasive monitoring product is reduced, the use cost of a patient is reduced, and the popularity of the cerebral blood oxygen non-invasive monitoring product is improved.

5. The cerebral blood oxygen noninvasive monitoring device disclosed by the invention also has good expansibility, and the richness of the functions of the system is easy to realize. For example, different algorithm models are designed and adopted according to different processing modes of acquired data by selecting different functional designs of a monitoring processing subsystem (upper computer), so that different types of monitoring of local blood oxygen saturation values of the brain, such as relative and absolute brain blood oxygen saturation, can be realized; in addition, the same hardware board card can be added to be connected with a reserved interface of a microcontroller core board, tissue blood oxygen data and the like of different positions of multiple channels can be collected, and therefore hardware support functions can be expanded.

6. The cerebral blood oxygen noninvasive monitoring device disclosed by the invention adopts a modular all-in-one machine design, and the modules are connected through simple ordered flat cables, so that the later maintenance of the cerebral blood oxygen noninvasive monitoring device and the updating and upgrading treatment of hardware boards are facilitated. The noninvasive acquisition subsystem (lower computer) and the monitoring processing subsystem (upper computer) are integrally packaged in a case shell, and only a charging interface, an acquisition probe interface and a power supply switch are reserved outside, so that the exposure of the line connection of the upper computer and the lower computer is avoided, the anti-interference capability of the cerebral blood oxygen device is improved, the workload of medical staff is reduced, the complicated line connection work is avoided, the risk of medical accidents is reduced, and the safety of patient monitoring is improved; therefore, an independent miniaturized device can be formed, and the device has the advantages of portability, good flexibility, low cost, convenience in popularization and strong adaptability.

7. The brain blood oxygen noninvasive monitoring device can optimize the well-designed human-computer interaction function, simplify the operation and enhance the display effect, can display the brain blood oxygen waveform and the brain blood oxygen value, and can display the reference value and the relative variation of the corresponding monitoring area so as to facilitate the observation and comparison of multiple parameters and timely react when abnormal conditions occur; and the adjustment control of the signal acquisition mode and the display mode can be realized through the design of system setting of a human-computer interaction interface, so that the system is suitable for more modes to deal with more application scenes.

Drawings

Fig. 1 is a schematic block diagram of the cerebral blood oxygen apparatus of the present invention.

Fig. 2 is a schematic diagram of a design of a brain blood oxygen collecting probe of the brain blood oxygen device of the present invention.

Fig. 3 is a schematic diagram of a signal preprocessing circuit for acquiring cerebral blood oxygen information in the cerebral blood oxygen apparatus of the present invention.

Fig. 4 is a block diagram of an exemplary process of executing a brain blood oxygen data collecting process by a microcontroller in the brain blood oxygen device according to the present invention.

Fig. 5 is a diagram illustrating an example of a control timing sequence for a microcontroller to perform four channels of cerebral blood oxygen information collection in the cerebral blood oxygen apparatus according to the present invention.

Fig. 6 is a flowchart illustrating an example of establishing communication connection between an upper computer and a lower computer in the cerebral blood oxygen apparatus according to the present invention.

Fig. 7 is a front view perspective structure schematic diagram of the brain blood oxygen apparatus all-in-one machine scheme of the invention.

Fig. 8 is a schematic left-view perspective structure view of the integrated cerebral blood oxygen apparatus of the present invention.

Detailed Description

In recent years, more and more scientific researchers develop brain blood oxygen non-invasive monitoring equipment at home and abroad, but the mature equipment is still scarce in terms of the current domestic situation, and the foreign brain blood oxygen non-invasive monitoring equipment is expensive in purchase price, high in diagnosis cost and low in domestic popularization rate. Therefore, the invention can effectively fill part of the vacancy in the field and provide certain support for the development of the domestic cerebral blood oxygen monitoring equipment. For the problem of monitoring the cerebral blood oxygen signal, due to the particularity of the application environment, the equipment is often used in the clinical operation environment, so the types of the monitoring position and the monitoring parameter need to be fully considered. Firstly, the object of the invention is a patient who is operated after clinical anesthesia, and the patient is usually laid on an operating table, so that the monitored cerebral blood oxygen signal is less interfered, and the area of the head of the human body corresponding to the forehead lobe of the brain is selected as a cerebral blood oxygen non-invasive monitoring area. The research of non-invasive monitoring is also in consideration of the operation experience of patients, the detection of the cerebral blood oxygen value in most of domestic operations at present is obtained by analyzing the blood and gas of arterial and venous blood, and the methods cannot achieve continuous monitoring and are traumatic and have certain danger. In the operation, two pieces of information related to the cerebral blood oxygen, which are needed by doctors most, are the change condition of the cerebral blood oxygen signal waveform, and whether severe mutation occurs or not; and secondly, the cerebral blood oxygen value of the human body is in a stable range when the human body is in a normal state, and if the value is abnormal or fluctuates greatly during the operation, a certain means is required to make up the cerebral blood oxygen value.

By combining the background reasons, more intensive research shows that the signal which interferes with the monitoring of the cerebral blood oxygen in the head tissue of the human body mainly comes from the influence of melanin components in the skin tissue of the human body on the continuous monitoring of the cerebral blood oxygen signal, the melanin components can absorb near infrared light, if the absorption of the melanin components is not monitored, the absorption of hemoglobin on the near infrared light is high, the interference can be generated on the final cerebral blood oxygen value, and the calculated cerebral blood oxygen value is not real. Further research finds that the absorption coefficient of the melanin component in the human body to red light is far greater than that of hemoglobin, so that the variation of the optical density of emergent light after the red light irradiates a monitoring area can be approximately considered to be mainly caused by the absorption of the melanin component in the human body; in addition, in the near infrared band, the absorption coefficient of human melanin to near infrared light does not change much as the wavelength increases. Therefore, the condition that the red light is absorbed by the brain blood oxygen non-invasive monitoring area can be taken as the representation of the interference signal to the head tissue of the human body, and the interference signal value is removed, so that the stability and the accuracy of the brain blood oxygen non-invasive monitoring are improved.

Based on the research, the invention provides a cerebral blood oxygen noninvasive monitoring device. The method aims to realize continuous real-time cerebral blood oxygen monitoring of a patient by utilizing a continuous cerebral blood oxygen prediction model through the difference of the absorption degrees of two hemoglobins of a human brain on red light and near infrared light, and provides a new solution for noninvasive monitoring of cerebral blood oxygen.

The brain blood oxygen non-invasive monitoring device comprises a brain blood oxygen information acquisition probe, a non-invasive acquisition subsystem and a monitoring processing subsystem, and the schematic diagram of the brain blood oxygen non-invasive monitoring device is shown in figure 1. The brain blood oxygen information acquisition probe can be designed as an independent detection acquisition device, the noninvasive acquisition subsystem can be designed as an independent lower computer, and the monitoring processing subsystem can be designed as an independent upper computer; the brain blood oxygen information acquisition probe and the end of the lower computer can be connected in a data transmission way in a data interface way; the lower computer end and the upper computer end can establish data transmission connection through wired communication modes such as a data transmission serial port and the like or wireless communication modes such as Bluetooth, WIFI and the like. The brain blood oxygen information acquisition probe is used for acting on an area of the head of a human body corresponding to the prefrontal lobe of the brain to serve as a brain blood oxygen non-invasive monitoring area to acquire the photoelectric information of the brain blood oxygen; the acquired brain blood oxygen photoelectric information comprises: the method comprises the steps of collecting the absorption condition of red light by a brain blood oxygen non-invasive monitoring area as a characteristic value of interference signals to human head tissues, collecting the absorption conditions of infrared light with two different wavelengths by the brain blood oxygen non-invasive monitoring area as a characteristic value of the concentration of local oxygenated hemoglobin in a brain prefrontal lobe area and the concentration of local reduced hemoglobin in the brain prefrontal lobe area, and collecting the absorption condition of infrared light with wavelengths of absorption points such as hemoglobin and the like by the brain blood oxygen non-invasive monitoring area as a characteristic value of individual difference correction factors. The non-invasive acquisition subsystem is used for carrying out brain blood oxygen photoelectric information acquisition control on the brain blood oxygen information acquisition probe and transmitting the acquired brain blood oxygen photoelectric information to the monitoring processing subsystem. The monitoring processing subsystem is used for carrying out cerebral blood oxygen monitoring analysis processing on the cerebral blood oxygen photoelectric information, respectively obtaining a local oxyhemoglobin concentration value of a prefrontal lobe area and a local reduced hemoglobin concentration value of the prefrontal lobe area, from which human head tissue interference signals are removed, so as to calculate and obtain a local blood oxygen saturation monitoring value of the prefrontal lobe area from which the human head tissue interference signals are removed, and further carrying out individual difference correction on the local blood oxygen saturation monitoring value of the prefrontal lobe area by using the individual difference correction factor to obtain cerebral blood oxygen non-invasive monitoring result data.

The brain blood oxygen non-invasive monitoring device has the working principle that the area of the head of a human body, which corresponds to the forehead of the brain, is used as a brain blood oxygen non-invasive monitoring area, the absorption condition of the brain blood oxygen non-invasive monitoring area to red light is collected and used as a characteristic value of an interference signal to the head tissue of the human body, and the absorption conditions of the brain blood oxygen non-invasive monitoring area to two kinds of infrared light with different wavelengths are collected and used as characteristic values of the concentration of oxygenated hemoglobin and the concentration of reduced hemoglobin of the brain, so that a surface interference signal and a deep useful signal of the brain blood oxygen non-invasive monitoring area are obtained. Based on the method, the cerebral blood oxygen signal with high signal-to-noise ratio is obtained through processing, and then the cerebral oxygenated hemoglobin concentration value and the cerebral reduced hemoglobin concentration value which do not contain the human head tissue interference signal are obtained, so that the cerebral blood oxygen saturation monitoring value without the human head tissue interference signal is obtained, and the non-invasive monitoring of the cerebral blood oxygen is realized.

According to the cerebral blood oxygen noninvasive monitoring device, the monitoring part selects the area of the human head corresponding to the forehead of the brain, dense hair coverage is avoided, interference is reduced, near infrared light can better penetrate extracranial tissues to enter the brain tissues, and information containing deep cerebral tissue blood oxygen saturation is obtained. In addition, the interference of melanin in human tissues is considered, the absorption condition of red light is used as the representation of the interference signal of the melanin in the human head tissues, the cerebral blood oxygen saturation monitoring value for removing the interference signal of the human head tissues is convenient to obtain, and the cerebral blood oxygen continuous monitoring has better stability and higher monitoring precision.

In order to better embody the technical feasibility and technical advantages of the noninvasive cerebral blood oxygen monitoring device of the present invention, the noninvasive cerebral blood oxygen monitoring device of the present invention is further described below.

1. The design of the brain blood oxygen noninvasive monitoring sensing probe.

In the cerebral blood oxygen non-invasive monitoring device, one or more groups of cerebral blood oxygen information acquisition probes for acquiring cerebral blood oxygen information can be designed. The main structural design of each group of blood oxygen information acquisition probes comprises a soft sticky material patch and an acquisition probe connector; one surface of the soft sticky material patch is used as a joint part which is jointed on the head of a human body corresponding to the prefrontal area of the brain, and the other surface and the peripheral part of the soft sticky material patch are shielded by the soft shading shell and used for reducing the light interference of ambient light to the joint part. One surface of the soft sticky material patch serving as the attaching part is provided with a red light source with the luminous wavelength of 680 nm-700 nm, a first infrared light source with the luminous wavelength of 760 nm-790 nm, a second infrared light source with the luminous wavelength of 840 nm-900 nm, a third infrared light source with the luminous wavelength of 800 nm-820 nm and two photodetectors arranged at intervals. The method comprises the steps of detecting the difference value of the emergent light intensity of red light reflected by a red light source irradiating the cerebral blood oxygen non-invasive monitoring area through two photodetectors as a characteristic value of interference signals to human head tissues, detecting the difference value of the emergent light intensity of infrared light reflected by a first infrared light source irradiating the cerebral blood oxygen non-invasive monitoring area through the two photodetectors as a characteristic value of local reduced hemoglobin concentration of a prefrontal lobe area, detecting the difference value of the emergent light intensity of infrared light reflected by a second infrared light source irradiating the cerebral blood oxygen non-invasive monitoring area through the two photodetectors as a characteristic value of local oxygenated hemoglobin concentration of the prefrontal lobe area, and detecting the difference value of the emergent light intensity of infrared light reflected by a third infrared light source irradiating the cerebral blood oxygen non-invasive monitoring area through the two photodetectors as a characteristic value of an individual difference correction factor. And the power supply ends of the red light source, the first infrared light source, the second infrared light source and the third infrared light source and the signal output ends of the two photoelectric detectors are electrically connected with the collected signal output joint through cables and are used for carrying out data transmission with the non-invasive collecting subsystem.

Besides, the specific design of the brain blood oxygen information collecting probe can also take some detail factors into consideration as follows.

1, a) in order to miniaturize the volume of the brain blood oxygen information acquisition probe as much as possible, various light sources can be designed in an integrated mode as much as possible, and a red light source, a first infrared light source, a second infrared light source and a third infrared light source in the brain blood oxygen information acquisition probe are preferentially arranged and integrated next to each other to form a multi-light-source patch lamp set; therefore, for the type selection of the multiple light source patch lamp set, the specification of selecting the four wavelengths of LED light sources to be integrally packaged as one multiple light source patch lamp set is preferably considered. LEDs with four wavelengths are selected, wherein a red light source with the light-emitting wavelength of 700nm, a first infrared light source with the light-emitting wavelength of 760nm, a second infrared light source with the light-emitting wavelength of 850nm and a third infrared light source with the light-emitting wavelength of 805nm are preferably selected respectively. The red light with the wavelength of 700nm is used for monitoring the absorption condition of melanin components in skin tissues to the red light and representing interference signals of head tissues; the red light with the wavelength of 760nm is used for monitoring the concentration change condition of the deoxyhemoglobin and is used for representing the concentration of the reduced hemoglobin; near infrared light with wavelength of 805nm is an equal absorption point of two hemoglobin and is used for representing individual difference; near infrared light of 850nm wavelength is used to monitor the change in the concentration of oxyhemoglobin and is used to characterize the concentration of oxyhemoglobin. The 5050-specification multi-light-source patch lamp group is selected, the LED lamps with various wavelengths are closely arranged, the space occupied by each LED is greatly reduced, the condition that the LEDs with various wavelengths and two photoelectric detectors are approximately in a linear relation in spatial arrangement is guaranteed, spatial offset in the signal acquisition process is negligible, the signal acquisition precision is guaranteed, and the signal-to-noise ratio of the cerebral blood oxygen signal is greatly improved.

1, b) similarly, in order to miniaturize the volume of the brain blood oxygen information acquisition probe and consider the design of detection precision, the type selection of the photoelectric detector preferentially selects a high-precision photoelectric detector with 5054 specification, the packaging specification of the photoelectric detector is similar to that of an LED, and the linear relation between the LED and the photoelectric detector on the spatial arrangement is favorably ensured. In addition, the wavelength receiving range of the selected photoelectric detector comprises four wavelengths of the multi-light-source patch lamp group, and light of the LEDs with the four wavelengths after diffuse reflection of forehead tissues can be effectively received. Meanwhile, the selected photoelectric detector has higher sensitivity, can receive optical signals after diffuse reflection of the deep brain tissue, and effectively detects the cerebral blood oxygen information of the deep brain tissue.

1, c) for the selection of the probe wrapping material, black soft sticky substances are preferred. Firstly, the material has good biocompatibility, and can not cause any harm to human bodies after long-term contact. Secondly, this material has fine flexibility, when having guaranteed the person's that is detected comfort level, can also closely laminate human forehead and reduce energy loss, can also fine protection inlay many light sources paster banks and photoelectric detector wherein. In addition, the black material is selected for shading, light leakage is avoided, and interference of ambient light on brain blood oxygen information acquisition is prevented. Finally, the adhesive material is selected, so that the brain blood oxygen non-invasive monitoring sensing probe is convenient to fix, the brain blood oxygen non-invasive monitoring sensing probe is effectively prevented from shifting or even falling off in the brain blood oxygen signal acquisition process, and the accuracy of brain blood oxygen information acquisition is improved.

1, d) selecting the specification of the connecting data wire between the soft adhesive material patch and the collecting probe connector, preferably selecting the connecting wire carrying the shielding layer. The shielding layer of the connecting wire is connected with the shell ground of the equipment, so that the brain blood oxygen signal is prevented from being interfered by electromagnetic signals generated by the instrument and electric charges carried on the human body.

1, e) designing the space arrangement between the multiple light source patch lamp group and the photoelectric detector on the flexible adhesive patch according to the forehead tissue structure of the human body. Because the skull and the extracranial tissue of the human body do not have great effect on monitoring the blood oxygen saturation of the brain tissue, the interference of the part is eliminated. The thickness of human skull and extracranial tissue is about 1cm thick, the distance between the brain tissue of the forehead leaf and the skull is about 1cm, and the distance between the photoelectric detectors and the LED is twice of the penetration depth of the LED light source, so that the two photoelectric detectors and the multi-light source patch lamp set are preferably ensured to be in a linear relationship in spatial arrangement, meanwhile, the arrangement distance between the two photoelectric detectors and the multi-light source patch lamp set is preferably 15-25 mm, preferably 20mm, according to the relationship, and the arrangement distance between the second photoelectric detector and the multi-light source patch lamp set is twice of the arrangement distance between the first photoelectric detector and the multi-light source patch lamp set, and is 30-50 mm, preferably 40 mm. A preferred arrangement of the two photodetectors P1 and the multiple light source patch lamp group P2 on the side of the attachment portion P0 of the flexible adhesive material patch is shown in fig. 2. Therefore, the LED and the two photoelectric detectors with each wavelength are approximately in a linear relation in spatial arrangement, spatial offset in the signal acquisition process can be ignored, the signal acquisition accuracy can be better ensured, and the signal to noise ratio of the brain blood oxygen signal acquisition is greatly improved.

2. And (4) designing a non-invasive acquisition subsystem.

The non-invasive collection subsystem is mainly designed to comprise a collection probe interface for carrying out electric signal connection with a brain blood oxygen information collection probe, a signal preprocessing circuit for carrying out signal conversion and filtering amplification preprocessing on collected brain blood oxygen photoelectric information, a light source driving circuit for carrying out light source driving on the brain blood oxygen information collection probe, a microcontroller for executing brain blood oxygen photoelectric information collection control and data transmission control, and a collection communication module for carrying out data communication transmission with a monitoring processing subsystem. Microcontroller carries out data transmission with gathering communication module and is connected, and carry out the electricity through light source drive circuit and signal preprocessing circuit and gather probe interface and be connected, be used for through the signal connection between gathering probe interface and the cerebral blood oxygen information acquisition probe, control light source drive circuit drive cerebral blood oxygen information acquisition probe carries out the collection of cerebral blood oxygen photoelectric information, and the cerebral blood oxygen photoelectric information who gathers transmits to microcontroller through signal preprocessing circuit and realizes the control of cerebral blood oxygen photoelectric information acquisition, microcontroller still is used for transmitting the cerebral blood oxygen photoelectric information who gathers to the monitoring processing subsystem through gathering communication module.

In the non-invasive collection subsystem, the design quantity of the collection probe interfaces, the signal preprocessing circuit and the light source driving circuit needs to be correspondingly grouped with the arrangement quantity of the cerebral blood oxygen information collection probes, namely, several groups of cerebral blood oxygen information collection probes need to be designed, and several groups of collection probe interfaces, the signal preprocessing circuit and the light source driving circuit need to be correspondingly arranged. In addition, the specific design of the non-invasive acquisition subsystem may take into account some of the following details.

2.1, the non-invasive collection subsystem is used for driving the brain blood oxygen non-invasive monitoring sensing probe.

2.1.a) for the construction of the light source driving circuit in the non-invasive collection subsystem, preferably adopting a constant current source driving circuit with a constant current source driving chip as a core, wherein the current output end of the constant current source driving circuit is electrically connected with a red light source, a first infrared light source, a second infrared light source and a third infrared light source in the brain blood oxygen information collection probe through a collection probe interface, and the enabling control end of the constant current source driving circuit is electrically connected with the microcontroller. The constant current source driving chip is externally connected with a load resistor and is used for regulating and controlling the current of the constant current source. The constant current source driving chip enable control end is the enable control end of the constant current source driving circuit, is connected with a pin of the microcontroller and is used for controlling the switch of the constant current source driving chip. The current output end of the constant current source driving chip is used as the current output end of the constant current source driving circuit and is connected with a multi-light-source patch lamp group in the brain blood oxygen information acquisition probe through an acquisition probe interface. The constant current source driving chip with a plurality of channels can be adopted, the LED lamps with the same wavelength of the plurality of brain blood oxygen noninvasive monitoring sensing probes can be controlled to be turned on and off simultaneously, and the synchronism of brain blood oxygen information acquisition of the plurality of brain blood oxygen noninvasive monitoring sensing probes is ensured.

2.1.b) for the external drive control of the light source driving circuit, a microcontroller is adopted to output PWM signal type control through an I/O pin of the microcontroller, and the light source driving circuit is controlled to drive a red light source, a first infrared light source, a second infrared light source and a third infrared light source in the brain blood oxygen information acquisition probe to perform light emitting work. In specific implementation, the driving control mode of the constant current source module can be selected according to a data manual of the constant current source driving chip. When the enabling end of the constant current source driving chip receives a high level signal, the constant current source driving chip enables, and the current output end of the constant current source driving chip outputs a constant current; when the enable end receives a low level signal, the constant current source driving chip is closed, and the current output end stops working. The LED lamps with four wavelengths can be controlled to be alternately turned on and off by adopting the PWM wave with high and low levels which appear in a crossed manner to control the light source driving circuit.

2.2, the non-invasive collection subsystem collects the cerebral blood oxygen photoelectric information.

The main circuit design of each signal preprocessing circuit in the non-invasive acquisition subsystem comprises a current-voltage conversion circuit unit, a primary blocking circuit unit, a primary low-pass filter circuit unit, a primary amplifying circuit unit, a secondary low-pass filter circuit unit, a secondary amplifying circuit unit, a secondary blocking circuit unit and a voltage lifting circuit unit which are electrically connected in sequence. If there are multiple channels of brain blood oxygen information acquisition probes, it is necessary to design multiple channels of signal preprocessing circuits correspondingly, as shown in fig. 3.

2.2.a) the current-voltage conversion circuit unit is used for converting current signals of a photoelectric detector in the brain blood oxygen information acquisition probe into voltage signals. For the current-voltage conversion circuit, a current-voltage conversion chip with large across-stop bandwidth, low bias current, small bias voltage, low temperature drift and low quiescent current is selected as a core. The high-precision current-voltage conversion chip is selected, so that the photoelectric signal received by the photoelectric detector can be effectively converted into a voltage signal which can be processed. The current-voltage conversion chip needs to carry a large resistor on a peripheral circuit module, plays a role in voltage amplification on photocurrent, and converts a weak current signal received from a photoelectric detector end into a voltage signal which can be processed. Meanwhile, a series of capacitors are carried in a peripheral circuit to play a role in signal filtering and filter noise interference.

2.2.b) the primary blocking circuit unit is used for carrying out primary direct current signal filtering processing on the voltage signal. The primary blocking circuit is mainly provided with a large-capacitance mounted resistor. After the current-voltage conversion circuit converts the current signals received by the photoelectric detector into voltage signals, some direct current signals are mixed in the voltage signals, the direct current signals are filtered, the brain blood oxygen signals are effectively stored, and meanwhile, direct current components are removed, so that subsequent amplification processing is facilitated.

2.2.c) for the primary low-pass filter circuit, an operational amplifier with high input impedance, wide common mode, low input bias current and low power consumption is selected as a circuit core. Because the frequency range of the cerebral blood oxygen signal is extremely low and is generally below 1Hz, in order to effectively store the effective components of the collected cerebral blood oxygen signal, a low-pass filter circuit with the cut-off frequency of 10Hz is selected, and the useful signal is stored to the maximum extent while the high-frequency interference noise signal above 10Hz is filtered out, so that the useful signal components are not attenuated. The primary low-pass filter circuit takes an operational amplifier as a core, and carries a peripheral filter capacitor resistor, so that the low-pass filter circuit with the cut-off frequency of 10Hz is realized.

2.2.d) the primary amplification circuit unit is used for carrying out amplification processing on the voltage signal for the first time. For the primary amplifying circuit, an operational amplifier with high input impedance, wide common mode, low input bias current and low power consumption is selected as a circuit core. Because the cerebral blood oxygen signal is weak, the amplitude range capable of carrying out A/D sampling can be achieved by amplifying for many times. Due to the fact that the single amplification factor is too large, large noise interference can be introduced into the cerebral blood oxygen signal, the cascade form of the multistage amplification circuit is selected, and the effects that the cerebral blood oxygen signal can be effectively amplified and the large noise interference can be effectively avoided are achieved. The primary amplifying circuit takes an operational amplifier as a core, carries a peripheral resistor, and selects a feedback resistor with proper resistance value, so that the amplification factor reaches 30-40 times. The amplification factor of the primary amplification circuit unit is preferably designed to be 36 times.

2.2.e) for the two-stage low-pass filter circuit unit, an operational amplifier with high input impedance, wide common mode, low input bias current and low power consumption is also selected as a circuit core. Because the low-pass filtering is carried out, the first-stage amplification is carried out, in order to prevent noise interference introduced by the circuit, a second-stage amplification circuit is used, the cut-off frequency is also 10Hz, high-frequency interference noise signals above 10Hz are filtered, and the cerebral blood oxygen signals are purified. The second-stage low-pass filter circuit takes an operational amplifier as a core, and carries a peripheral filter capacitor resistor, so that the low-pass filter circuit with the cut-off frequency of 10Hz is realized.

And 2.2.f) the secondary amplifying circuit unit is used for carrying out secondary amplification processing on the voltage signal. For the two-stage amplifying circuit, an operational amplifier with high input impedance, wide common mode, low input bias current and low power consumption is selected as a circuit core. The amplitude of the brain blood oxygen signal after primary amplification is lower, and the brain blood oxygen signal after filtering processing is subjected to secondary amplification. The second-stage amplifying circuit takes an operational amplifier as a core, carries a peripheral resistor, and selects a feedback resistor with proper resistance value, so that the amplification factor reaches 10-15 times. The amplification factor of the two-stage amplification circuit unit is preferably designed to be 10 times.

And 2.2.g) the secondary DC blocking circuit unit is used for carrying out secondary DC signal filtering processing on the voltage signal. And for the secondary blocking circuit, a large capacitor is selected to carry a resistor. The brain blood oxygen signal amplified for many times inevitably introduces some direct current components, and a secondary blocking circuit is used for removing direct current interference to obtain a relatively pure brain blood oxygen signal.

And 2.2.h) the voltage boosting circuit unit is used for boosting the voltage signal to reach the voltage acquisition range of the microcontroller. For the voltage boost circuit, an operational amplifier with high input impedance, wide common mode, low input bias current and low power consumption is selected as a circuit core. The operational amplifier used for filtering and amplifying the cerebral blood oxygen signal uses double power supplies until the voltage is raised by the voltage raising module, the voltage of the obtained cerebral blood oxygen signal has a negative value, and in order to prevent the loss of useful information of the cerebral blood oxygen signal, the addition circuit is used, so that the voltage change of the cerebral blood oxygen signal is completely changed into a positive value and is within the voltage range in which the microcontroller can carry out A/D acquisition.

And 2.3, the microcontroller collects and processes the cerebral blood oxygen information.

The microcontroller controls the A/D acquisition module to perform A/D acquisition on the cerebral blood oxygen signals processed by the cerebral blood oxygen information acquisition module, and if a plurality of groups of cerebral blood oxygen information acquisition probes exist, multi-channel continuous sampling can be selected, and the cerebral blood oxygen signals with four wavelengths of four channels are sampled at a sampling rate of 2000 Hz.

The microcontroller enables the timer and A/D conversion to drive the light source driving block, so that LEDs with four wavelengths are lighted alternatively, the photoelectric receiver converts received optical signals into current signals, the current signals pass through the information acquisition module, and finally, the A/D conversion module of the microcontroller converts the acquired cerebral blood oxygen analog signals into digital signals.

A total of 5A/D samples may be taken during the light emission interval of each LED. The microcontroller further processes the obtained brain blood oxygen digital signal. In order to avoid interference of an afterglow effect of an LED on the collected cerebral blood oxygen signal, the collected cerebral blood oxygen signal is abandoned, 5 groups of data collected in a light-emitting interval of each LED lamp are abandoned, the front 2 groups of data are abandoned, the rear 3 groups of data are reserved, and the data values of the rear 3 groups are averaged to serve as the data value in the light-emitting interval of the LED with the current wavelength.

The microcontroller is internally provided with a receiving cache array and a sending cache array, when the receiving cache array is full of 100ms of data, the receiving cache array transfers the data to the sending cache array, and meanwhile, the receiving cache array is emptied and used for receiving new data. And the sending cache array sends the data in the sending cache array to the upper computer, and after the sending cache array completely sends the data to the upper computer, the sending cache array is emptied, and the next time of storing and receiving the data transferred by the cache array is waited.

A flow chart of the acquisition and processing of the cerebral blood oxygen data by the microcontroller is shown in fig. 4.

In addition, the microcontroller can be designed to control the light source driving circuit to drive the red light source, the first infrared light source, the second infrared light source and the third infrared light source in the brain blood oxygen information acquisition probe to alternately emit light through time-sharing intervals, so that the photoelectric detector in the brain blood oxygen information acquisition probe can detect the emergent light intensity reflected by the brain blood oxygen non-invasive monitoring area irradiated by different light sources at different time intervals. If a plurality of groups of cerebral blood oxygen information acquisition probes exist, the time sequence control of the cerebral blood oxygen signal acquisition can be respectively carried out on each group of cerebral blood oxygen information acquisition probes in a multi-channel mode. For example, as shown in fig. 5, if there are four channels of cerebral blood oxygen information acquisition, the cerebral blood oxygen data of the four channels are separated according to the time sequence control of the microcontroller on the cerebral blood oxygen signal acquisition, and the cerebral blood oxygen data of 4 wavelengths of each channel are separated at the same time. The time sequence of the microcontroller controlling the light emitting of the LED lamps with four wavelengths can be respectively designed as follows: the lamp at 700nm is on, and the lamps at other 3 wavelengths are off; the lamps at 760nm are on, and the lamps at other 3 wavelengths are off; the 805nm lamp is on, and the other 3 wavelengths are off; the 850nm lamp was on and the other 3 wavelengths were off. And the data of the first channel is acquired by the time sequence of the A/D sampling, the data of the first channel is acquired, the data of the second channel is acquired, and the like until the data of the four channels are acquired. Based on this timing, the data for each channel and each wavelength for each channel can be completely separated out for later processing.

5. The connection and data transmission between the non-invasive acquisition subsystem (lower computer) and the monitoring processing subsystem (upper computer).

The communication mode between the non-invasive acquisition subsystem (lower computer) and the monitoring processing subsystem (upper computer) is that data transmission is directly carried out if the communication mode is wired communication; if the wireless communication is adopted, the data transmission between the wireless communication connection and the wireless communication connection can be executed after the connection is completed by selecting and establishing the wireless communication connection. During wireless communication connection and specific application, the software of the upper computer can be opened, a correct communication mode is selected according to different configurations of the lower computer, the upper computer starts to search for corresponding communication equipment until pairing connection is completed, and a connection pairing flow between the upper computer and the lower computer is shown in fig. 6. After the upper computer and the lower computer are connected in a matched mode, the upper computer sends an opening instruction, the lower computer receives the instruction to start working, the acquired data are packaged and sent to the upper computer in a data packet mode, the situation that data are dropped due to the fact that sampling is conducted while sending the data is avoided, and stability and safety of the acquired cerebral blood oxygen data are guaranteed.

6. And the monitoring processing subsystem processes, displays and stores the cerebral blood oxygen data.

The monitoring processing subsystem comprises a monitoring communication module for carrying out data communication transmission with the non-invasive acquisition subsystem, a monitoring processor for carrying out cerebral blood oxygen monitoring analysis on cerebral blood oxygen photoelectric information, a data storage module for carrying out data storage, and a display module for carrying out data display on the cerebral blood oxygen non-invasive monitoring result. The monitoring communication module is used for acquiring the cerebral blood oxygen photoelectric information acquired by the non-invasive acquisition subsystem through the monitoring communication module, respectively calculating a local oxyhemoglobin concentration value of a prefrontal lobe area and a local reduced hemoglobin concentration value of the prefrontal lobe area, from which human head tissue interference signals are removed, so as to calculate and obtain a local blood oxygen saturation monitoring value of the prefrontal lobe area from which the human head tissue interference signals are removed, and further performing individual difference correction on the local blood oxygen saturation monitoring value of the prefrontal lobe area by using the individual difference correction factor, so that cerebral blood oxygen non-invasive monitoring result data is obtained, and the display module is controlled to display the data.

In addition, the specific design of the monitoring processing subsystem may take into account some of the details as follows.

And 6.a) for processing the cerebral blood oxygen signal, firstly, carrying out digital filtering once by adopting a self-adaptive filtering method to filter low-frequency noise superposed on the cerebral blood oxygen signal. Because the low-frequency signals of respiration, heartbeat and the like are inevitably introduced in the process of collecting the cerebral blood oxygen signals, the low-frequency signals cannot be filtered only by a low-pass filter of a hardware circuit and the superposition average processing in a microcontroller, and in order to reduce the interference on the cerebral blood oxygen signals, the self-adaptive filtering method is adopted to filter the components of the low-frequency signals of respiration, heartbeat and the like superposed on the cerebral blood oxygen signals.

6, b) in the monitoring processing subsystem, the data of the noninvasive monitoring result of the cerebral blood oxygen obtained by processing of the monitoring processor is a partial blood oxygen saturation monitoring value rSO of the prefrontal area of the brain corrected by individual difference₂(P), can be calculated using the brain blood oxygen model as follows:

wherein, K₁、K₂Respectively a first correction coefficient and a second correction coefficient;

local reduction of hemoglobin concentration, C, in the prefrontal area of the brain to remove interfering signals from human head tissue_HbRLocal oxygenated hemoglobin concentration value, C, in the prefrontal area of the brain for removing interfering signals of human head tissues_IDIs an individual difference correction factor and has:

wherein, Δ OD^redThe difference value of the emergent light intensity of the red light reflected by the two photodetectors in the cerebral blood oxygen non-invasive monitoring area is detected; delta OD^inf1The two photodetectors are used for detecting the difference value of the emergent light intensity of the infrared light reflected by the brain blood oxygen noninvasive monitoring area irradiated by the first infrared light source; delta OD^inf2The two photodetectors are used for detecting the difference value of the emergent light intensity of the infrared light reflected by the brain blood oxygen noninvasive monitoring area irradiated by the second infrared light source;

respectively representing molar extinction coefficients of the brain reduced hemoglobin aiming at the first infrared light source, the second infrared light source and the third infrared light source;

respectively represents the molar extinction coefficients of the brain oxyhemoglobin aiming at the first infrared light source, the second infrared light source and the third infrared light source.

When the method is applied specifically, the model can be programmed and realized based on application software at a computer terminal, and the dual-channel cerebral blood oxygen value is calculated in real time based on the cerebral blood oxygen noninvasive prediction model and displayed in a human-computer interaction interface, so that the real-time condition of a tested person can be conveniently observed, and meanwhile, the reference value and the relative variation of the cerebral local tissue blood oxygen saturation are displayed.

And 6, c) calculating the cerebral blood oxygen value and drawing a waveform, substituting the cerebral blood oxygen data subjected to the adaptive filtering treatment into a cerebral blood oxygen model, calculating the cerebral blood oxygen value, and realizing real-time display of the cerebral blood oxygen waveform by using a winform-carried control. The brain blood oxygen signal processed by the self-adaptive filtering is clean and pure, the data of four wavelengths received by the far and near two photoelectric detectors are directly substituted into the brain blood oxygen model to obtain the absolute value and the relative value of the current brain blood oxygen value, and the absolute value and the relative value are displayed on a human-computer interaction interface. And displaying the absolute value of the cerebral blood oxygen on a canvas carried by winform. The method comprises the steps that firstly, calculated cerebral blood oxygen data values are stored in a large array, the length of the large array is the number of data points of cerebral blood oxygen required by displaying a whole screen cerebral blood oxygen curve, and the required number of data points of the cerebral blood oxygen value is determined according to the time length of the screen data. The canvas is updated again every 300ms, the data in the first 300ms of the array is removed, and the data in the last 300ms of the array is added, so that the brain blood oxygen curve appears to move continuously to the left side along with the time, and the effect of continuous dynamic display is achieved. When the value of cerebral blood oxygen is abnormal, the upper computer sends an instruction to the lower computer, the microcontroller controls the hardware board to give an alarm, and the doctor is alerted to take corresponding measures in time.

And 6, d) the monitoring processing subsystem stores data through the data storage module, can include any one or more of collected cerebral blood oxygen photoelectric data, processed cerebral blood oxygen noninvasive monitoring result data, drawn cerebral blood oxygen waveform data and the like, and is convenient to look up. For the storage of cerebral blood oxygen data, two storage modes can be designed, one mode is that a doctor selects to store the cerebral blood oxygen data by himself, and the other mode is that the doctor selects a default storage mode. The doctor selects the folder for storing data, the doctor needs to select the folder for storing the data, and after the folder is selected, the acquired cerebral blood oxygen original data, the cerebral blood oxygen absolute value and the relative value data are stored in the three subfolders and stored below the selected folder. The doctor selects a default storage mode, the upper computer software firstly establishes a folder according to the information of the patient, then establishes subfolders according to the inquiry time of the patient, and stores the original data of the cerebral blood oxygen, the absolute value and the relative value data in the three folders and stores the data in the subfolders established according to the file time of the patient. And the data storage is completed, so that the doctor can conveniently carry out subsequent research and analysis on the cerebral blood oxygen change condition of the patient.

7) An all-in-one machine design scheme of a cerebral blood oxygen noninvasive monitoring device.

The cerebral blood oxygen non-invasive monitoring device can also adopt the design scheme of an all-in-one machine, namely, a cerebral blood oxygen information acquisition probe is used as an information acquisition pluggable component, and a non-invasive acquisition subsystem and a monitoring processing subsystem are integrated into the non-invasive monitoring all-in-one machine.

As shown in fig. 7 and 8, the integrated noninvasive monitoring machine comprises a housing 1, the side of the housing facing the user when in use is defined as an operation surface 11 of the housing, and a display panel arrangement space near the operation surface of the housing, a battery arrangement space near the upper part of the back of the housing, and an integrated circuit arrangement space near the lower part of the back of the housing are arranged in the housing. The operation surface of the cabinet housing 10 is provided with a display window 12 at a position corresponding to the display panel arrangement space, and the back surface or the side surface of the lower part of the cabinet housing 10 is provided with an interface mounting hole 13 and a charging port mounting hole 14 at a position corresponding to the integrated circuit arrangement space. A battery 20 is installed in the battery arrangement space of the housing 10 for supplying power to the devices of the non-invasive acquisition subsystem and the monitoring processing subsystem. An acquisition probe interface in the non-invasive acquisition subsystem is arranged at the position of an interface mounting hole 13 of the chassis shell. The display module 30 in the monitoring processing subsystem is installed in the display panel arrangement space of the case shell, and the display surface of the display module is arranged opposite to the display window 12 on the case shell. Install integrated circuit board 40 in the integrated circuit arrangement space of casing 10, it all integrates on integrated circuit board not have signal preprocessing circuit, light source drive circuit, microcontroller and the monitoring communication module, monitoring processor and the data storage module of gathering communication module and monitoring processing subsystem among the collection subsystem, and still integrated on integrated circuit board has the power supply control circuit and the control circuit that charges that carry out the electricity with the battery and be connected. The power supply control circuit is a power supply connection circuit for supplying power to each device of the noninvasive acquisition subsystem and the monitoring processing subsystem by a battery, a power supply switch 41 is connected in the power supply control circuit, and the power supply switch 41 is installed on the outer surface of the chassis shell 10. The charging interface is further installed at the position of the charging interface installation hole 14 of the case shell 10, and the charging interface is electrically connected to the battery through the charging control circuit and used for being connected to a power supply and charging the battery through the charging control circuit. The top of the housing 10 may also be provided with a suspension bracket 15 for suspension fixation during clinical use.

By the design, on one hand, the internal space of the case shell can be fully utilized, so that the noninvasive acquisition subsystem and the monitoring processing subsystem are highly integrated into the noninvasive monitoring all-in-one machine, the space utilization rate is improved, the overall volume of the noninvasive monitoring all-in-one machine is not too large, and the product miniaturization design of the noninvasive monitoring all-in-one machine is facilitated; on the other hand, when considering that the clinical use, the noninvasive monitoring all-in-one machine is mainly used for hanging and establishing fixed use scenes (can be hung on a wall or an infusion support, and excessive ground space occupation is avoided), in the components of the noninvasive monitoring all-in-one machine, the battery with relatively heavy weight is arranged in the space close to the upper part in the case shell, the display module with relatively light weight and the integrated circuit board are respectively arranged in the space close to the front part and the lower part in the case shell, so that the whole gravity center of the noninvasive monitoring all-in-one machine is close to the upper part, the noninvasive monitoring all-in-one machine is more favorable for hanging and establishing fixed stability for hanging and establishing fixed equipment, meanwhile, a charging interface, a collection probe interface and the like are arranged in the lower part area of the case shell, and the noninvasive monitoring all-in-one machine is convenient for a user to operate.

An example description of the noninvasive cerebral blood oxygen monitoring operation of the noninvasive cerebral blood oxygen monitoring device of the present invention is given below to embody the detection operation and processing procedures of the noninvasive cerebral blood oxygen monitoring device of the present invention:

step 1) connecting and attaching the cerebral blood oxygen probe.

In the step, a connecting wire interface is connected with an interface of the non-invasive collection subsystem, and the brain blood oxygen non-invasive monitoring sensing probe is connected with a connecting wire of the brain blood oxygen non-invasive monitoring device, so that the connecting work of the brain blood oxygen non-invasive monitoring sensing probe is completed. A pair of cerebral blood oxygen non-invasive monitoring sensing probes are respectively attached to the head of a human body in the area corresponding to the forehead of the brain, the attachment parts of the cerebral blood oxygen non-invasive monitoring sensing probes are at least 2cm above the upper part of an eyebrow, and the frontal midline is avoided to prevent the influence of the venous sinuses on the acquisition of the cerebral blood oxygen information, and in addition, the attachment parts of the left cerebral blood oxygen non-invasive monitoring sensing probe and the right cerebral blood oxygen non-invasive monitoring sensing probe are symmetrical about the frontal midline.

And 2) connecting the upper computer system with the lower computer system.

The brain blood oxygen noninvasive monitoring device is started, and the system power supply supplies power to the upper computer system and the lower computer system. Starting an upper computer software system of the cerebral blood oxygen noninvasive monitoring device, inputting patient information, starting automatic searching and pairing of an upper computer, and trying to establish communication connection in a wired mode (such as a serial port) or a wireless mode (WiFi or Bluetooth) with a lower computer system by the upper computer until the communication connection between the upper computer and the lower computer is completed.

And 3) driving the cerebral blood oxygen probe by the lower computer.

After the communication connection between the upper computer and the lower computer is successfully established, the upper computer clicks a start button, the upper computer sends a starting instruction to the lower computer, and the lower computer judges the instruction after receiving the instruction and makes a corresponding action. When the lower computer determines that the command received from the upper computer is started, the lower computer exits from the low power consumption mode and starts to operate. The microcontroller controls the on-off state of the constant current source chip in a PWM wave mode, so that the constant current source chip is controlled to be switched between a rated current output state and an off state. Therefore, the LED lamps with four wavelengths of the cerebral blood oxygen probe are controlled to be alternately lightened, and the power of each LED lamp is ensured to be consistent when the LED lamps are lightened.

And 4) collecting cerebral blood oxygen information by the lower computer.

The LED lamps with various wavelengths of the brain blood oxygen noninvasive monitoring sensing probe sequentially penetrate through the scalp, the subcutaneous tissue, the skull, the cerebrospinal fluid and the deep brain tissue in a banana arc path, finally sequentially penetrate through the cerebrospinal fluid, the skull, the subcutaneous tissue and the scalp, and are received by a remote photoelectric detector. The LED lamps with various wavelengths of the cerebral blood oxygen probe sequentially penetrate through the scalp, the subcutaneous tissue and the skull in a banana arc path, finally sequentially penetrate through the subcutaneous tissue and the scalp, and are received by the near-end photoelectric detector. The photoelectric detector converts the received optical signals into current signals, and in order to realize subsequent signal processing, the current signals containing the cerebral blood oxygen information are converted into voltage signals through a current-voltage conversion circuit. And then a direct current isolating circuit is followed to remove the direct current bias in the cerebral blood oxygen information. Then a 10Hz low-pass filter circuit is followed to filter out high-frequency noise. And then, the primary amplification circuit is used for carrying out primary amplification on the cerebral blood oxygen signal, the 10Hz filter circuit is used for filtering high-frequency noise, and then the secondary amplification circuit is used for enabling the amplitude of the cerebral blood oxygen signal to be in the range capable of carrying out AD sampling. And removing unnecessary direct current components by using a direct current isolating circuit, and enabling the cerebral blood oxygen signal to be in an amplitude range capable of carrying out A/D sampling by using a voltage raising circuit. All the configurations of the four channels are completely the same, and the accuracy of analyzing and processing the cerebral blood oxygen data is ensured.

And 5) data transmission between the lower computer and the upper computer.

A total of 5A/D samples were taken during the light emission interval of each LED. The microcontroller further processes the obtained brain blood oxygen digital signal. In order to avoid interference of an afterglow effect of an LED on the collected cerebral blood oxygen signal, the collected cerebral blood oxygen signal is abandoned, 5 groups of data collected in a light-emitting interval of each LED lamp are abandoned, the front 2 groups of data are abandoned, the rear 3 groups of data are reserved, and the data values of the rear 3 groups are averaged to serve as the data value in the light-emitting interval of the LED with the current wavelength. Two large arrays are created inside the microcontroller, namely an accepting buffer array and a sending buffer array. When the receiving cache array is full of 100ms of data, the receiving cache array transfers the data to the sending cache array, meanwhile, the receiving cache array is emptied to receive new data, the sending cache array sends the data to the upper computer, and after the sending cache array completely sends the data to the upper computer, the sending cache array is emptied to wait for the next time of receiving the data transferred by the cache array.

And 6) processing and storing the cerebral blood oxygen data by the upper computer.

The upper computer separates the cerebral blood oxygen data of the four channels according to the time sequence control of the microcontroller on the acquisition of the cerebral blood oxygen signals, and simultaneously separates the cerebral blood oxygen data of 4 wavelengths of each channel. The time sequence of the microcontroller controlling the light emitting of the LED lamps with the four wavelengths is respectively as follows: the lamp at 700nm is on, and the lamps at other 3 wavelengths are off; the lamps at 760nm are on, and the lamps at other 3 wavelengths are off; the 805nm lamp is on, and the other 3 wavelengths are off; the 850nm lamp was on and the other 3 wavelengths were off. And the data of the first channel is acquired by the time sequence of the A/D sampling, the data of the first channel is acquired, the data of the second channel is acquired, and the like until the data of the four channels are acquired. Based on this timing, the data for each channel and each wavelength for each channel can be completely separated out. And then filtering low-frequency noise such as heartbeat, respiration and the like superposed on the cerebral blood oxygen signal by adopting a self-adaptive filtering method. And calculating the absolute value and the relative value of the cerebral blood oxygen by using the cerebral blood oxygen model. And displaying the absolute value and the relative value of the cerebral blood oxygen on a human-computer interaction interface, and drawing a cerebral blood oxygen waveform according to the calculated cerebral blood oxygen value by using a canvas control carried by a winform. In the process of monitoring the cerebral blood oxygen signal, the cerebral blood oxygen curve fluctuates too much or the absolute value and the relative value of the cerebral blood oxygen change greatly, the lower computer of the upper computer sends an instruction, an alarm bell is turned on, and alarm information is displayed on a human-computer interaction interface. And after the monitoring of the cerebral blood oxygen signals is completed, storing the cerebral blood oxygen data.

In summary, the present invention develops a non-invasive monitoring device for the blood oxygen saturation of the local brain tissue based on the different absorption of oxyhemoglobin and deoxyhemoglobin to near infrared light, which comprises a brain blood oxygen information collecting probe, a non-invasive collecting subsystem and a monitoring processing subsystem, wherein the region of the head corresponding to the forehead of the brain is used as a brain blood oxygen non-invasive monitoring region, the absorption of the red light by the brain blood oxygen non-invasive monitoring region is used as the characteristic value of the interference signal to the head tissue of the human body, the absorption of the infrared light with two different wavelengths by the brain blood oxygen non-invasive monitoring region is used as the characteristic values of the brain oxyhemoglobin concentration and the brain reduced hemoglobin concentration, so as to obtain the surface interference signal and the deep useful signal of the brain blood oxygen non-invasive monitoring region, and further process to obtain the brain oxyhemoglobin concentration value and the brain reduced hemoglobin concentration value without the interference signal of the head tissue of the human body, therefore, the monitoring value of the cerebral blood oxygen saturation without the human head tissue interference signal is obtained, and the non-invasive monitoring of the cerebral blood oxygen is realized. The device can not cause the injury to the human body, and can be stable, accurate realization to the continuous real-time supervision of brain blood oxygen value. The method comprises the steps that an autonomously designed brain blood oxygen information acquisition probe with four-wavelength photoelectric signal acquisition is adopted, so that when oxyhemoglobin and reduced hemoglobin in local brain tissues are detected, interference signals in skin tissues in a test area are also detected, and in addition, near infrared light with one wavelength is added in consideration of individual difference and is used for calculating a correction factor; in addition, the brain blood oxygen information acquisition probe adopts the mode of pegging graft to improve convenience and interference immunity of brain blood oxygen device, be convenient for the change of brain blood oxygen noninvasive monitoring sensing probe, reduce the replacement cost of brain blood oxygen information acquisition probe. According to the cerebral blood oxygen noninvasive monitoring device, the monitoring area selects the area of the human head corresponding to the forehead of the brain without dense hair coverage, so that the interference is reduced, near infrared light can smoothly penetrate extracranial tissues to enter the brain tissues, and the information containing the deep cerebral tissue blood oxygen saturation is obtained; in addition, the influence of melanin in human tissues is considered, the red light absorption condition is used as the representation of melanin interference signals of human head tissues, surface interference signals and deep useful signals are detected respectively, the acquired signal content is richer, the brain blood oxygen signals with high signal-to-noise ratio are obtained through convenient processing, and then the brain blood oxygen saturation monitoring value for removing the human head tissue interference signals is obtained, so that the brain blood oxygen continuous monitoring stability is better, and the monitoring precision is higher. The design of the cerebral blood oxygen non-invasive monitoring device can be researched and developed based on an embedded technology, so that the hardware cost and the development cost of the product are greatly reduced, the price of the cerebral blood oxygen non-invasive monitoring product is reduced, the use cost of a patient is reduced, and the popularity of the cerebral blood oxygen non-invasive monitoring product is improved. The cerebral blood oxygen noninvasive monitoring device also has good expansibility, and the richness of the functions of the system is easy to realize. For example, different algorithm models are designed and adopted according to different processing modes of acquired data by selecting different functional designs of a monitoring processing subsystem (upper computer), so that different types of monitoring of local blood oxygen saturation values of the brain, such as relative and absolute brain blood oxygen saturation and the like, can be realized; in addition, the same hardware board card can be added to be connected with a reserved interface of a microcontroller core board, so that tissue blood oxygen data and the like of multiple channels at different positions can be acquired, and the expansion of hardware support functions is realized. And as a preferred design scheme, the cerebral blood oxygen noninvasive monitoring device adopts a modular all-in-one machine design, and the modules are connected through simple ordered flat cables, so that the later maintenance of the cerebral blood oxygen noninvasive monitoring device and the updating and upgrading treatment of hardware boards are facilitated. The noninvasive acquisition subsystem (lower computer) and the monitoring processing subsystem (upper computer) are integrally packaged in a case shell, and only a charging interface, an acquisition probe interface and a power supply switch are reserved outside, so that the exposure of the line connection of the upper computer and the lower computer is avoided, the anti-interference capability of the cerebral blood oxygen device is improved, the workload of medical staff is reduced, the complicated line connection work is avoided, the risk of medical accidents is reduced, and the safety of patient monitoring is improved; therefore, an independent miniaturized device can be formed, and the device has the advantages of portability, good flexibility, low cost, convenience in popularization and strong adaptability. In the aspect of software, the noninvasive cerebral blood oxygen monitoring device can optimize the well-designed human-computer interaction function so as to simplify the operation and enhance the display effect, and can display the reference value and the relative variation of a corresponding monitoring area while displaying the cerebral blood oxygen waveform and the cerebral blood oxygen value so as to facilitate multi-parameter observation and comparison and timely react when abnormal conditions occur; and the adjustment control of the signal acquisition mode and the display mode can be realized through the design of system setting of a human-computer interaction interface, so that the system is suitable for more modes to deal with more application scenes.

Therefore, the invention provides a new solution for noninvasive monitoring of cerebral blood oxygen, improves the stability and accuracy of noninvasive monitoring of cerebral blood oxygen, and is more favorable for promoting clinical application of noninvasive monitoring of cerebral blood oxygen.

Finally, it is noted that the above-mentioned embodiments illustrate rather than limit the invention, and that, while the invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1.A cerebral blood oxygen non-invasive monitoring device is characterized by comprising a cerebral blood oxygen information acquisition probe, a non-invasive acquisition subsystem and a monitoring processing subsystem;

2. The noninvasive cerebral blood oxygen monitoring device according to claim 1, characterized in that the cerebral blood oxygen information collecting probe comprises a soft adhesive material patch and a collecting probe connector;

3. The noninvasive cerebral blood oxygen monitoring device according to claim 2, characterized in that the red light source, the first infrared light source, the second infrared light source and the third infrared light source in the cerebral blood oxygen information collecting probe are arranged and integrated next to each other to form a multi-light-source patch lamp set; the arrangement distance between a first photoelectric detector in the two photoelectric detectors and the multi-light-source patch lamp group is 15-25 mm, and the arrangement distance between a second photoelectric detector and the multi-light-source patch lamp group is twice of the arrangement distance between the first photoelectric detector and the multi-light-source patch lamp group.

4. The cerebral blood oxygen non-invasive monitoring device according to claim 2, wherein the non-invasive collection subsystem comprises a collection probe interface for electrically connecting with the cerebral blood oxygen information collection probe, a signal preprocessing circuit for performing signal conversion and filtering amplification preprocessing on the collected cerebral blood oxygen photoelectric information, a light source driving circuit for performing light source driving on the cerebral blood oxygen information collection probe, a microcontroller for performing cerebral blood oxygen photoelectric information collection control and data transmission control, and a collection communication module for performing data communication transmission with the monitoring processing subsystem; microcontroller carries out data transmission with gathering communication module and is connected, and carry out the electricity through light source drive circuit and signal preprocessing circuit and gather probe interface and be connected, be used for through the signal connection between gathering probe interface and the cerebral blood oxygen information acquisition probe, control light source drive circuit drive cerebral blood oxygen information acquisition probe carries out the collection of cerebral blood oxygen photoelectric information, and the cerebral blood oxygen photoelectric information who gathers transmits to microcontroller through signal preprocessing circuit and realizes the control of cerebral blood oxygen photoelectric information acquisition, microcontroller still is used for transmitting the cerebral blood oxygen photoelectric information who gathers to the monitoring processing subsystem through gathering communication module.

5. The cerebral blood oxygen noninvasive monitoring device of claim 4, characterized in that the light source driving circuit is a constant current source driving circuit, the current output end of which is electrically connected with the red light source, the first infrared light source, the second infrared light source and the third infrared light source in the cerebral blood oxygen information acquisition probe through the acquisition probe interface, and the enabling control end of the light source driving circuit is electrically connected with the microcontroller;

6. The cerebral blood oxygen noninvasive monitoring device of claim 4, wherein the microcontroller drives the red light source, the first infrared light source, the second infrared light source and the third infrared light source in the cerebral blood oxygen information acquisition probe to alternately emit light through the time-sharing interval control light source driving circuit, so that the photodetector in the cerebral blood oxygen information acquisition probe can detect the intensity of emergent light reflected by the cerebral blood oxygen noninvasive monitoring area irradiated by different light sources at different time intervals.

7. The cerebral blood oxygen noninvasive monitoring device of claim 4, characterized in that the signal preprocessing circuit comprises a current-voltage conversion circuit unit, a primary DC blocking circuit unit, a primary low-pass filter circuit unit, a primary amplification circuit unit, a secondary low-pass filter circuit unit, a secondary amplification circuit unit, a secondary DC blocking circuit unit and a voltage raising circuit unit which are electrically connected in sequence;

8. The cerebral blood oxygen non-invasive monitoring device according to claim 4, wherein the monitoring processing subsystem comprises a monitoring communication module for data communication transmission with the non-invasive collection subsystem, a monitoring processor for cerebral blood oxygen monitoring analysis of the cerebral blood oxygen photoelectric information, a data storage module for data storage, and a display module for data display of the cerebral blood oxygen non-invasive monitoring result; the monitoring communication module is used for acquiring the cerebral blood oxygen photoelectric information acquired by the non-invasive acquisition subsystem through the monitoring communication module, respectively calculating a local oxyhemoglobin concentration value of a prefrontal lobe area and a local reduced hemoglobin concentration value of the prefrontal lobe area, which are used for removing human head tissue interference signals, so as to calculate and obtain a local blood oxygen saturation monitoring value of the prefrontal lobe area, from which the human head tissue interference signals are removed, and further performing individual difference correction on the local blood oxygen saturation monitoring value of the prefrontal lobe area by using the individual difference correction factor, so that cerebral blood oxygen non-invasive monitoring result data is obtained, and the display module is controlled to display the data.

9. The cerebral blood oxygen non-invasive monitoring device according to claim 8, wherein the non-invasive collection subsystem and the monitoring processing subsystem are integrated into a non-invasive monitoring all-in-one machine;

10. The noninvasive cerebral blood oxygen monitoring device according to claim 9, characterized in that a suspension bracket is further provided on the top of the housing of the machine case.