CN112168181B - Brain tissue blood oxygen saturation detection device and preparation method thereof - Google Patents

Abstract

The invention discloses a brain tissue blood oxygen saturation detection device and a preparation method thereof, wherein the brain tissue blood oxygen saturation detection device comprises: the measuring body is composed of a plurality of optical fibers which are arranged side by side and fixedly connected with each other, one optical fiber is used as an outgoing optical fiber, the other optical fibers are used as incoming optical fibers, the tip ends of the incoming optical fibers and the outgoing optical fibers are separated by a preset distance, and the mirror surfaces with preset angles are formed by precision cutting or grinding.

Description

A device for detecting blood oxygen saturation in brain tissue and its preparation method

technical field

The invention relates to the technical field of medical devices, in particular to a brain tissue blood oxygen saturation detection device and a preparation method thereof.

Background technique

With the continuous development of modern medical technology and related disciplines, medical monitoring instruments have become an indispensable category of medical electronic instruments, and play an increasingly important role in hospitals. The use of monitoring instruments not only reduces the labor of medical staff, improves the efficiency of medical care, but more importantly, enables doctors to understand the condition in time.

Oxygen supply to brain tissue is the material basis for maintaining the most basic signs of life and advanced life activities (consciousness, thinking, and action). Hypoxia in brain tissue can lead to disturbance of consciousness, hemiplegia, even coma, and death. Understanding the oxygen content in brain tissue has important clinical significance. For patients with craniocerebral injury, cerebral hemorrhage, and craniotomy, it is often accompanied by brain tissue edema, increased intracranial pressure, and insufficient cerebral blood perfusion, so that the oxygen supply to the brain tissue is insufficient, and oxygen partial pressure or oxygen saturation decreases. Seriously threaten the quality of life and life safety of patients, and bring a heavy burden to medical resources and society. Therefore, monitoring the oxygen content of brain tissue is an urgent problem to be solved in clinical practice.

At present, there are two main ways to monitor the oxygen content of brain tissue:

1. Invasive monitoring: that is, the surgical method, the sensor is inserted into the brain tissue through the drill hole on the skull, or the bony seam between the bone flap formed by the craniotomy and the skull, and walks through the subcutaneous tunnel to poke the sensor from the scalp The hole leads out and connects to the external host computer. The upper computer measures the partial pressure of oxygen in the brain tissue through specific signal processing methods and algorithms. At present, the mature products mainly include the German Raumedic cerebral oxygen partial pressure monitoring system and the American Camino cerebral partial pressure oxygen monitoring system. The former (Raumedic) coats the tip (single end) of the ultra-thin Y-shaped optical fiber with a fluorescent substance, which is coated with a biocompatible gas-permeable film material, and oxygen molecules can diffuse to the fluorescent substance. When an external laser with a specific wavelength is injected through a branch at the end of the Y-shaped fiber, the fluorescent substance is excited at a certain pulse frequency, and the fluorescent substance generates fluorescence of a specific wavelength after being excited. Oxygen molecules diffuse from the brain tissue through the gas-permeable membrane and come into contact with fluorescent substances, causing fluorescence quenching. The fluorescent signal can be led out through another branch at the end of the Y-shaped fiber. By analyzing the fluorescence lifetime or intensity with an external device, the oxygen content at the tip can be calculated, so as to understand the partial pressure of oxygen in the brain. The latter (Camino) makes Clark electrodes (materials such as Au, Ag or Pt) at the tip of the catheter. Oxygen in the brain tissue permeates the cell membrane, participates in the electrochemical reaction between the electrodes, and generates current. By monitoring the current between the electrodes with external equipment, the brain oxygen content at the electrodes can be known.

However, in fact, both the optical fiber sensor based on laser excitation fluorescence quenching and the electrochemical sensor based on the Clark electrode principle have relatively large limitations. The brain oxygen monitored by the two sensors is the oxygen molecule infiltrated from the brain tissue cells. The former oxygen molecules need to pass through the gas-permeable membrane, and the oxygen molecule permeability of the gas-permeable membrane seriously affects the accuracy of the measurement results. Moreover, when the monitoring time is a little longer, the fluorescent substance will be greatly inactivated or even lost, which seriously affects the measurement accuracy. In the latter, once blood clots or other substances are attached to the surface of the Clark electrode (a very common situation), the oxygen in the brain tissue will not be able to participate in the electrochemical reaction between the electrodes, resulting in inaccurate or even failure of measurement. In addition, the current generated by the electrochemical sensor is weak, and the signal is easily disturbed during transmission, which affects the measurement accuracy.

Because of the above limitations and the high production cost of the sensors of the two technical routes, even though, as mentioned above, cerebral oxygen monitoring is of great significance, these two types of sensors are hardly used in clinical practice.

2. Non-invasive monitoring: Non-invasive cerebral oxygen monitoring based on the principle of NIRS (Near Infrared Spectroscopy) has been applied clinically in recent years. The basic principle is: the blood oxygen saturation sensor is attached to the forehead of the patient's brain, and the blood oxygen sensor probe is equipped with two different bands of visible light and near-infrared diodes, as well as a photoelectric sensor that can accept this band. The light signals of two frequencies emitted by visible light and infrared diodes pass through the scalp and skull, enter the brain tissue, are scattered by various cells in the brain tissue, return in a parabola-like arc, pass through the skull, scalp and other tissues, and are absorbed by the scalp The attached photoelectric sensor receives. For hemoglobin and oxyhemoglobin, the absorption peaks correspond to the emitted light signals of the two frequencies. According to the Lambert-Beer law, the absorption intensity of optical signals in the two frequency bands is positively correlated with the concentration of hemoglobin and oxyhemoglobin. The ratio of oxyhemoglobin to hemoglobin reflects the oxygen saturation in brain tissue.

The above method is convenient for monitoring and low in cost, but its limitations are also obvious: after visible light or near-infrared light passes through the skin, it needs to pass through the skull before entering the brain tissue. The thinner part of the skull. At present, these products can only be applied to the forehead, and there is no hair covering the area. Even so, the light signal needs to pass through the skull twice to enter the brain tissue and scatter to the photoelectric sensor. The blood supply of the scalp and the skull itself will also absorb and reflect the photoelectric signal, resulting in large background noise. And after passing through the scalp and skull, the signal attenuation is serious, so the detectable brain tissue is superficial, about 5-10mm deep in the brain tissue. Moreover, the optical signal is diffuse, so it cannot be accurately positioned, and the brain oxygen condition of specific brain tissue cannot be monitored.

Contents of the invention

In order to overcome the deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide a brain tissue blood oxygen saturation detection device and its preparation method, so that by designing a simple reflection structure at the tip of the optical fiber, the optical signal is introduced and extracted to realize The need for monitoring the oxygen saturation of specific parts of the brain.

In order to achieve the above and other purposes, the present invention proposes a brain tissue blood oxygen saturation detection device, including: a measurement body, the measurement body is composed of several optical fibers arranged side by side and fixed to each other, one of which is used as an outgoing Optical fibers, and the rest of the optical fibers are used as incoming optical fibers. The tips of each incoming optical fiber and outgoing optical fiber are separated by a preset distance, and are precisely cut or ground to form a mirror surface with a preset angle.

Preferably, the optical fibers are fixed by bonding with an implantable medical device adhesive.

Preferably, the tip of each optical fiber is precisely cut or ground to form a bevel with a preset angle, and the bevel is plated with gold or other metals to form a mirror surface.

Preferably, the exterior of the metal is coated or otherwise modified to make it biocompatible for use within brain tissue.

Preferably, heat-shrinkable tubes and coatings are used outside each optical fiber to make the surface regular and keep the positional relationship of the optical fibers within it fixed.

Preferably, the distance between the tips of the incoming optical fiber and the outgoing optical fiber depends on the need for detection depth during design.

Preferably, the mirror angle formed by the tip of each optical fiber is 0°-90°, excluding 0° and 90°.

Preferably, at a certain length at the tip of each optical fiber, the optical fiber is ground, cubed, and prism processed, and then a mirror surface with a preset angle is formed to destroy the total reflection of light in the optical fiber, so that the light can be emitted or transmitted.

In order to achieve the above object, the present invention also provides a method for preparing a brain tissue blood oxygen saturation detection device, comprising the following steps:

Step S1, precision cutting or grinding the tips of several optical fibers to form a mirror surface with a preset angle;

In step S2, the plurality of optical fibers are arranged side by side and fixed to each other, one of the optical fibers is used as an outgoing optical fiber, and the remaining optical fibers are used as incoming optical fibers, and the tip of each incoming optical fiber is separated from the tip of the outgoing optical fiber by a preset distance.

Preferably, in step S1, the tip of each optical fiber is given a certain length, and the optical fiber is ground, cubed and prism processed to form a mirror surface with a preset angle, so as to destroy the total reflection of light in the optical fiber, so that the light is emitted or transmitted enter.

Compared with the prior art, the present invention provides a brain tissue blood oxygen saturation detection device and its preparation method, so that by designing a simple reflection structure at the tip of the optical fiber, the optical signal is introduced and extracted, and realized in the body (not only can It is brain tissue, and it can also be intravascular, liver, kidney, etc.) for the purpose of invasive tissue oxygen saturation monitoring.

Description of drawings

Fig. 1 is a schematic structural view of a brain tissue blood oxygen saturation detection device of the present invention;

2 is a schematic diagram of the principle of the brain tissue blood oxygen saturation detection device of the present invention;

Fig. 3 is a schematic diagram of avoiding total reflection of light in a specific embodiment of the present invention;

FIG. 4 is a flow chart of steps of a method for manufacturing a device for detecting blood oxygen saturation in brain tissue according to the present invention.

Detailed ways

The implementation of the present invention is described below through specific examples and in conjunction with the accompanying drawings, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific examples, and various modifications and changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

FIG. 1 is a schematic structural diagram of a brain tissue blood oxygen saturation detection device according to the present invention. As shown in Figure 1, a brain tissue blood oxygen saturation detection device of the present invention includes: a measuring body, the measuring body is arranged side by side, one of the optical fibers is used as an outgoing optical fiber, and the remaining optical fibers are used as incoming optical fibers. There is a certain distance between the tips of the incoming optical fibers and the outgoing optical fibers, and the optical fibers are fixed to each other, for example, by bonding (such as using an implantable adhesive for medical devices) to fix them. If necessary, they can be fixed at each Heat-shrinkable tube (C) and coating are used outside the optical fiber to make the surface regular and keep the positional relationship of the optical fiber inside; the tip of each optical fiber is precisely cut or ground to form a bevel at a certain angle, Gold plating or other metals are carried out on the slope to form a mirror surface. Preferably, the exterior of the metal can be coated or modified in other ways if necessary, so as to meet the biocompatibility for use in brain tissue. Preferably, for in vivo use, the optical fiber used should be sterilizable. In the present invention, the number of specific optical fibers and the angle of the slope can be adjusted according to actual needs.

In a specific embodiment of the present invention, two optical fibers (A, B) are taken as an example, wherein A is an incoming optical fiber, B is an outgoing optical fiber, and the distance between the tips of the incoming optical fiber A and the outgoing optical fiber B with two mirror surfaces is, Depending on the need for detection depth (detection range) during design, if a larger range of brain tissue needs to be detected, the distance between the two mirrored tips can be increased as required, and vice versa. The specific distance parameters are related to The relationship between the detection range can be calculated according to the parabola fitting formula, which has been disclosed in the literature of the prior art, and will not be repeated here.

For the angle of the two mirrors formed by the incoming fiber A and the outgoing fiber B, it can be set between 0°-90° (0° and 90° are not included here, because when 0°, the reflecting mirror is almost the same as the incident If the light is parallel, the diffuse reflection light cannot be reflected after entering the fiber; if it is 90°, the fiber cannot be processed). The specific angle value needs to be designed according to fiber processing and actual application scenarios. Generally speaking, when the light enters the light at 45°, it can be transmitted along the long axis of the light after being reflected by the mirror surface. Theoretically, the attenuation is the least, the maximum detection light intensity can be obtained, and the detection is more sensitive. Therefore, in the specific embodiment of the present invention, transmission The slope (M, N) angle between the input fiber A and the output fiber B is 45°, and the slope (M, N) is plated with gold or other metals to form a mirror.

As shown in Figure 2, when in use, optical signals of different frequencies are alternately introduced from the incoming fiber A, the signal is reflected by the M mirror at the tip of the incoming fiber A, and enters the brain tissue, and the scattered light is reflected by the N mirror of the B fiber, The optical signal is led out from the B optical fiber, and the in vitro device is used for synchronous measurement. When the light signals of the specific absorption peak wavelengths of hemoglobin and oxyhemoglobin are alternately introduced, the corresponding absorption intensity can be measured alternately, so as to understand the oxygen saturation of the brain tissue.

In fact, the change of oxygen saturation of brain tissue is relatively stable in the time of ms level. Therefore, when the optical signals of different wavelengths introduced by the incoming fiber A are switched at a faster frequency (ms level), it can be approximately considered that the measured The obtained hemoglobin absorption peak intensity and oxyhemoglobin absorption peak intensity are at the same time.

Preferably, if there are strict requirements, and it is necessary to "simultaneously" measure the absorption intensity of optical signals of two frequencies, an optical fiber can be added as an incoming optical fiber, which is still arranged side by side according to the above requirements, and its tip is spaced from the B optical fiber at a certain distance.

Preferably, total reflection of light needs to be avoided in order that the optical signal transmitted into the optical fiber can exit the optical fiber smoothly, and the optical signal reflected by the brain tissue can enter the outgoing optical fiber smoothly. Therefore, it is necessary to cut the fiber tip to a certain length, and process the original cylindrical shape into a prism or a cubic column with four sides by grinding or other means. Generally speaking, the function of an optical fiber is to allow light to transmit in the glass material without passing through the material, which means that the optical fiber cannot pass through the circular interface between the optical fiber and the surrounding air or other substances due to the principle of total reflection during transmission. Therefore, in the part where each fiber needs to be emitted or passed in (that is, at the mirror surface of the fiber tip), two methods including but not limited to the following can be adopted: 1. Corrosion with hydrofluoric acid (HF) on the surface of the fiber to make it "atomized" ", the smooth surface becomes rough, similar to the effect of "frosted glass", destroying the circular interface between the optical fiber and the adjacent medium to achieve the purpose of injection or transmission; 2. Grinding the circular interface to become a plane or polygon , can also make the light exit or pass in, as shown in Figure 3, only need to destroy the circular shape of the fiber interface at d, whether it is ground, atomized, or formed into other shapes (prisms), the light in the fiber can be destroyed The total reflection of the light exits or enters.

FIG. 4 is a flow chart of steps of a method for manufacturing a device for detecting blood oxygen saturation in brain tissue according to the present invention. As shown in Figure 4, a method for preparing a brain tissue blood oxygen saturation detection device of the present invention comprises the following steps:

In step S1, the tips of several optical fibers are precisely cut or ground to form a slope with a certain angle, and gold or other metals are plated on the slope to form a mirror surface.

In a specific embodiment of the present invention, the angle of each fiber tip bevel is between 0°-90° (excluding 0° and 90° here, because when 0°, the mirror surface is almost parallel to the incident light, and the diffuse reflection light enters It cannot be reflected behind the fiber; at 90°, the fiber cannot be processed). The specific angle value needs to be designed according to fiber processing and actual application scenarios. Generally speaking, when the light enters the light at 45°, it can be transmitted along the long axis of the light through mirror reflection. Theoretically, the attenuation is the least, the maximum detection light intensity can be obtained, and the detection is more sensitive. Therefore, in the specific embodiment of the present invention, Take two optical fibers A and B as an example. The tips are precisely cut or ground to form a tip bevel (M, N) with an angle of 45°, and the bevel (M, N) is plated with gold or other metals to form a mirror. If necessary, the exterior of the metal can be coated or modified in other ways to meet the biocompatibility for use in brain tissue.

In step S2, the plurality of optical fibers are arranged side by side and fixed to each other, one of which is used as an outgoing optical fiber, and the others are used as incoming optical fibers, and each incoming optical fiber is at a certain distance from the outgoing tip. In a specific embodiment of the present invention, each optical fiber is fixed by means of bonding or the like. If necessary, heat-shrinkable tubes, coatings, etc. can be used on the outside of the optical fiber to make the surface regular and keep the positional relationship of the optical fiber inside it fixed.

In the specific embodiment of the present invention, still taking the above two optical fibers (A, B) as an example, the A and B optical fibers are arranged side by side, with the tips separated by a certain distance, and are fixed by bonding or other methods, wherein A is the incoming optical fiber, and B is the incoming optical fiber. As the outgoing fiber, the distance between the two mirrored tips of the incoming fiber A and the outgoing fiber B depends on the need for detection depth (detection range) during design. If a larger range of brain tissue needs to be detected, the The distance between the tips of the two mirrors increases, and vice versa. The relationship between the specific distance parameter and the detection range can be calculated according to the parabola fitting formula, which has been disclosed in the literature of the prior art. Here I won't go into details.

Preferably, total reflection of light needs to be avoided in order that the optical signal transmitted into the optical fiber can exit the optical fiber smoothly, and the optical signal reflected by the brain tissue can enter the outgoing optical fiber smoothly. Therefore, in step S1 , it is also necessary to grind the tip of the optical fiber to a certain length, and process the original cylindrical shape into a prism or a cubic column with four sides by grinding or other means. Generally speaking, the function of an optical fiber is to allow light to transmit in the glass material without passing through the material, which means that the optical fiber cannot pass through the circular interface between the optical fiber and the surrounding air or other substances due to the principle of total reflection during transmission. Therefore, in the part where each fiber needs to be emitted or passed in (that is, at the mirror surface of the fiber tip), two methods including but not limited to the following can be adopted: 1. Corrosion with hydrofluoric acid (HF) on the surface of the fiber to make it "atomized" ", the smooth surface becomes rough, similar to the effect of "frosted glass", destroying the circular interface between the optical fiber and the adjacent medium to achieve the purpose of injection or transmission; 2. Grinding the circular interface to become a plane or polygon , also allows light to exit or enter.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Any person skilled in the art can modify and change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be listed in the claims.

Claims (10)

1. A brain tissue blood oxygen saturation detection device comprising: the measuring body is composed of a plurality of optical fibers which are arranged side by side and fixedly connected with each other, one optical fiber is used as an outgoing optical fiber, the other optical fibers are used as incoming optical fibers, the tip ends of the incoming optical fibers and the outgoing optical fibers are separated by a preset distance in the length direction of the optical fibers, and the optical fibers are precisely cut or ground to form a mirror surface with a preset angle;

and (3) grinding the optical fibers, processing the optical fibers by using a prism or a prism to form a mirror surface with a preset angle at a certain length at the tip of each optical fiber so as to destroy the total reflection of light in the optical fibers and enable the light to be emitted or transmitted.

2. A brain tissue blood oxygen saturation detection device according to claim 1, wherein: the optical fibers are fixed by adopting an adhesive of an implantable medical device in an adhesive mode.

3. A brain tissue blood oxygen saturation detection device according to claim 1, wherein: the tips of the optical fibers are precisely cut or ground to form inclined planes of a preset angle, and metal plating is performed on the inclined planes to form mirror surfaces.

4. A brain tissue blood oxygen saturation detection apparatus according to claim 3, wherein: the metal comprises gold.

5. A brain tissue blood oxygen saturation detection apparatus according to claim 3 or 4, wherein: modification is performed outside the metal to make it compatible for use in brain tissue.

6. A brain tissue blood oxygen saturation detection apparatus according to claim 5, wherein: the modification includes a coating.

7. A brain tissue blood oxygen saturation detection apparatus according to claim 6, wherein: the outer part of each optical fiber is provided with a heat shrinkage tube or a coating mode, so that the surface of each optical fiber is regular, and the position relation of the optical fiber in each optical fiber can be kept fixed.

8. A brain tissue blood oxygen saturation detection apparatus according to claim 6, wherein: the distance between the tips of the incoming and outgoing fibers depends on the design requirements for the depth of detection.

9. A brain tissue blood oxygen saturation detection apparatus according to claim 6, wherein: the tips of the fibers form a specular angle of 0 ° -90 °, excluding 0 ° and 90 °.

10. A preparation method of a brain tissue blood oxygen saturation detection device comprises the following steps:

step S1, precisely cutting or grinding the tips of a plurality of optical fibers to form a mirror surface with a preset angle;

s2, arranging the optical fibers side by side and fixedly connecting the optical fibers with each other, wherein one optical fiber is used as an outgoing optical fiber, the other optical fibers are used as incoming optical fibers, and the tip ends of the incoming optical fibers and the outgoing optical fibers are separated by a preset distance in the length direction of the optical fibers;

in step S1, the tips of the optical fibers are polished to a certain length, and then the optical fibers are processed into a mirror surface with a predetermined angle after being flattened, a prism or a prism, so as to destroy the total reflection of the light in the optical fibers and make the light emitted or transmitted.

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