CN112168181B

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

Info

Publication number: CN112168181B
Application number: CN202011114382.2A
Authority: CN
Inventors: 黄慧瑛
Original assignee: Guangzhou First Peoples Hospital
Current assignee: Guangzhou First Peoples Hospital
Priority date: 2020-10-16
Filing date: 2020-10-16
Publication date: 2023-07-11
Anticipated expiration: 2040-10-16
Also published as: CN112168181A

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

Brain tissue blood oxygen saturation detection device and preparation method thereof

Technical Field

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

Background

With the continuous development of modern medical technology and related disciplines, medical monitoring instruments have become an indispensable instrument for medical electronics, and play an increasingly important role in hospitals. The use of the monitoring instrument not only reduces the labor of medical staff and improves the efficiency of medical care work, but also enables doctors to know the illness state in time.

Oxygen supply to brain tissue is the material basis for maintaining vital basic signs, as well as advanced vital activities (consciousness, thinking, actions). Hypoxia of brain tissue can lead to disturbance of consciousness, hemiplegia, and even coma and death. The knowledge of the oxygen content in brain tissue has important clinical significance. For patients with craniocerebral injury, cerebral hemorrhage and craniotomy, cerebral tissue edema, intracranial pressure increase and cerebral tissue blood flow perfusion deficiency are often accompanied, so that oxygen supply to cerebral tissue is insufficient, oxygen partial pressure or oxygen saturation is reduced, the life quality and life safety of the patients are seriously threatened, and a heavy burden is brought to medical resources and society. Therefore, monitoring of the oxygenation of brain tissue is a critical issue in clinical practice

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

1. invasive monitoring: the sensor is inserted into brain tissue through a drill hole on the skull or a bone seam between a bone flap formed by craniotomy and the skull in a surgical mode, and is led out from a head skin poking hole in a subcutaneous tunnel running mode to be connected to an external upper computer. The upper computer measures the oxygen partial pressure of brain tissue through a specific signal processing method and algorithm. The current mature products mainly comprise a Germany Raumedic brain oxygen partial pressure monitoring system and a U.S. Camino brain oxygen partial pressure monitoring system. The former (raumadic) is coated with a fluorescent substance on the tip (single end) of an extremely fine Y-shaped optical fiber, and the outer surface is coated with a gas-permeable film material having biocompatibility, and oxygen molecules can diffuse to the fluorescent substance. When external laser with specific wavelength is injected through one branch at the tail end of the Y-shaped optical fiber, fluorescent substances are excited at a certain pulse frequency, and fluorescent light with specific wavelength is generated after the fluorescent substances are excited. Oxygen molecules diffuse from brain tissue through the gas permeable membrane and contact the fluorescent material, causing quenching of fluorescence. The fluorescent signal can be led out through the other branch of the tail end of the Y-shaped optical fiber. By analyzing the fluorescence lifetime or intensity through external equipment, the tip oxygen content can be calculated, so that the brain oxygen partial pressure condition can be known. The latter (Camino) then makes Clark electrode (Au, ag or Pt material) at the catheter tip, oxygen in brain tissue permeates cell membrane, takes part in electrochemical reaction between electrodes, and generates current. The brain oxygen content at the electrodes can be known by monitoring the current between the electrodes through external equipment.

However, in fact, there are major limitations to either fiber optic sensors based on laser-excited fluorescence quenching or electrochemical sensors based on the Clark electrode principle. The brain oxygen monitored by both sensors is an oxygen molecule that permeates out of brain tissue cells. The former oxygen molecules need to pass through the breathable film, and the oxygen molecule transmittance of the breathable film seriously influences the accuracy of the measurement result. And when the monitoring time is slightly long, the fluorescent substance can be greatly inactivated or even lost, and the measurement accuracy is seriously influenced. In the latter case, once there is a clot or other material attached to the surface of the Clark electrode (very often), oxygen in the brain tissue will not participate in the electrochemical reaction between the electrodes, resulting in inaccurate or even failure of the measurement. In addition, the current generated by the electrochemical sensor is weak, and the signal is very easy to be interfered in the transmission process, so that the measurement accuracy is affected.

As a result of the limitations described above, and the high production costs of both technical routes of sensors, even though brain oxygen monitoring is of great importance, both types of sensors have almost failed to be used clinically.

2. Non-invasive monitoring: noninvasive brain oxygen monitoring based on NIRS (near infrared spectroscopy) principle has been applied to clinic in recent years. The basic principle is as follows: the blood oxygen saturation sensor is attached to the forehead of the cranium of the patient, and the blood oxygen sensor probe is provided with two visible light diodes and near infrared diodes with different wave bands and a photoelectric sensor capable of receiving the wave bands. The light signals with two frequencies emitted by the visible light diode and the infrared diode penetrate through the scalp and the skull, enter brain tissues, are scattered by various cells in the brain tissues, return in a parabolic-like arc shape, penetrate through the tissues such as the skull and the scalp, and are received by the photoelectric sensor attached to the scalp. Hemoglobin and oxyhemoglobin, the absorption peaks correspond to the emitted two frequencies of optical signals. According to Lambert-Beer law, the absorption intensity of optical signals in two frequency bands is positively correlated with hemoglobin and oxygenated hemoglobin concentrations. And the ratio of oxyhemoglobin to hemoglobin, i.e., the oxygen saturation in brain tissue, is reflected.

The method is convenient to monitor and low in cost, but the limitation is also obvious: visible light or near infrared light needs to pass through the skull to enter brain tissue after passing through the skin, so that diodes and sensors are required to be closely attached to the scalp and can only be applied to the thinner parts of the skull. At present, the products can only be applied to the forehead without hair covering parts. Even if the optical signals enter brain tissues and scatter to the photoelectric sensor, the optical signals need to pass through the skull twice, and the scalp and the blood supply of the skull can absorb and reflect the optical signals, so that larger background noise is brought. And after passing through the scalp and the skull, the signal attenuation is serious, so that the detectable brain tissue is shallow, and the depth of the brain tissue is about 5-10 mm. And the optical signals are dispersed, so that the accurate positioning is not realized, and the brain oxygen condition of specific brain tissues cannot be monitored.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a brain tissue blood oxygen saturation detection device and a preparation method thereof, so that an optical signal is led in and led out by designing a simple reflection structure at the tip of an optical fiber, and the monitoring requirement of the brain oxygen saturation of a specific part is realized.

To achieve the above and other objects, the present invention provides 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, and the mirror surfaces with preset angles are formed by precision cutting or grinding.

Preferably, the optical fibers are secured by adhesive means using an implantable medical device.

Preferably, the tip of each optical fiber is precisely cut or ground to form a bevel of a predetermined angle, and gold plating or other metals are performed at the bevel thereof to form a mirror surface.

Preferably, the coating or other modification is done on the outside of the metal so that it meets the biocompatibility for use in brain tissue.

Preferably, a heat shrinkage tube and a coating are used outside each optical fiber, so that the surface of each optical fiber is regular, and the position relation of the optical fibers in each optical fiber can be kept fixed.

Preferably, the distance between the tips of the incoming and outgoing fibers depends on the design requirements for the depth of detection.

Preferably, the tips of the fibers form a specular angle of 0 ° -90 °, excluding 0 ° and 90 °.

Preferably, the optical fibers are polished flat, square columns and prisms at a certain length at the tips of the optical fibers, and then a mirror surface with a preset angle is formed, so that the total reflection of light in the optical fibers is destroyed, and the light is emitted or transmitted.

In order to achieve the above purpose, the invention also provides a preparation method of the brain tissue blood oxygen saturation detection device, comprising 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;

and S2, arranging the optical fibers side by side and fixedly connecting the optical fibers with each other, wherein one optical fiber serves as an outgoing optical fiber, the other optical fibers serve as incoming optical fibers, and the tip ends of the incoming optical fibers and the outgoing optical fibers are separated by a preset distance.

Preferably, in step S1, the tip of each optical fiber is polished to a certain length, and then the optical fiber is processed into a prism, and then a mirror surface with a predetermined angle is formed, so as to destroy the total reflection of the light in the optical fiber, and make the light emitted or transmitted.

Compared with the prior art, the invention provides the brain tissue blood oxygen saturation detection device and the preparation method thereof, so that the optical signals are led in and out through designing a simple reflection structure at the tip end of the optical fiber, and the aim of monitoring the oxygen saturation of the invasive tissue in vivo (not only brain tissue, but also blood vessel, liver, kidney and the like) is fulfilled.

Drawings

FIG. 1 is a schematic diagram of a brain tissue blood oxygen saturation detection device according to the present invention;

FIG. 2 is a schematic diagram of a brain tissue blood oxygen saturation detection device according to the present invention;

FIG. 3 is a schematic diagram illustrating the total reflection of light avoidance in an embodiment of the present invention;

fig. 4 is a flowchart showing steps of a method for manufacturing a brain tissue blood oxygen saturation detection device according to the present invention.

Detailed Description

Other advantages and effects of the present invention will become readily apparent to those skilled in the art from the following disclosure, when considered in light of the accompanying drawings, by describing embodiments of the present invention with specific embodiments thereof. The invention may be practiced or carried out in other embodiments and details within the scope and range of equivalents of the various features and advantages of the 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 fig. 1, a brain tissue blood oxygen saturation detection device of the present invention includes: the measuring body is formed by arranging a plurality of optical fibers side by side, wherein 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 at a certain distance, the optical fibers are fixedly connected with each other, for example, the optical fibers are fixed in a bonding mode (for example, an adhesive of an implantable medical device is adopted), if necessary, a heat shrinkage tube (C), a coating mode and the like can be used outside the optical fibers, so that the surfaces of the optical fibers are regular, and the position relation of the optical fibers in the optical fibers can be kept fixed; the tips of the individual fibers are precision cut or polished to form an angled bevel and gold plated or other metal is applied to the bevel to form a mirror surface. Preferably, the metal exterior may be coated or otherwise modified as necessary to provide biocompatibility for use in brain tissue. Preferably, to meet in vivo use, the optical fiber used should be sterilizable. In the invention, the number of specific optical fibers and the angle of the inclined plane can be adjusted according to actual requirements.

In the embodiment of the present invention, two optical fibers (a, B) are taken as an example, where a is an incoming optical fiber, B is an outgoing optical fiber, and the distances between two mirrored tips of the incoming optical fiber a and the outgoing optical fiber B depend on the requirements of detection depth (detection range) during design, if a larger range of brain tissue needs to be detected, the distance between two mirrored tips can be increased as required, and vice versa, and the specific relationship between the distance parameters and the detection range can be calculated according to a parabolic fitting formula, which is disclosed in the literature of the prior art and is not repeated herein.

The angle of the two mirrors formed by the incoming fiber a and the outgoing fiber B may be set to be between 0 ° -90 ° (here, 0 ° and 90 ° are not included, because when 0 ° is included, the reflecting mirror is almost parallel to the incident light, and the diffuse reflection light cannot be reflected after entering the fiber, and 90 °, the fiber cannot be processed). Specific angle values need to be designed according to the optical fiber processing and practical application scenes. Generally, at 45 °, the light enters the light, and the light can be transmitted along the long axis of the light through specular reflection, so that the light has the least attenuation theoretically, the maximum detection light intensity can be obtained, and the detection is more sensitive, so that in the embodiment of the present invention, the angle of the inclined plane (M, N) of the incoming optical fiber a and the outgoing optical fiber B is 45 °, and gold plating or other metals are performed at the inclined plane (M, N) to form a mirror surface.

As shown in fig. 2, in use, optical signals with different frequencies are alternately introduced from the incoming optical fiber a, the signals are reflected by the M mirror surface of the tip of the incoming optical fiber a, enter brain tissue, scattered light is reflected by the N mirror surface of the B optical fiber, the optical signals are led out from the B optical fiber, and synchronous measurement is performed in an extracorporeal device. When the optical signals with specific absorption peak wavelengths of the hemoglobin and the oxyhemoglobin are alternately introduced, the corresponding absorption intensities can be alternately measured, so that the oxygen saturation condition of the brain tissue can be known.

In fact, the oxygen saturation change of the brain tissue is relatively stable in the ms-scale time, so that when the switching frequency is fast (ms-scale) of the optical signals of different wavelengths introduced into the optical fiber a, the measured hemoglobin absorption peak intensity and the oxygenated hemoglobin absorption peak intensity can be approximately considered to be at the same time.

Preferably, if stringent requirements require "simultaneous" measurement of the optical signal absorption intensities at two frequencies, one fiber may be added as the incoming fiber, still arranged side-by-side as required, with its tip spaced a distance from the B fiber.

Preferably, in order that the optical signal transmitted into the optical fiber can be smoothly emitted out of the optical fiber, and that the optical signal reflected by brain tissue can be smoothly transmitted into the outgoing optical fiber, it is necessary to avoid the total reflection of light. Therefore, the optical fiber tip needs to be processed into a prism or a four-sided cubic column by grinding or the like with a certain length. Generally, the optical fiber is used to transmit light in a glass material without transmitting through the material, which means that the optical fiber cannot pass through a circular interface between the optical fiber and the surrounding air or other substances due to the principle of total reflection. Thus, where each fiber is required to be ejected or launched (i.e., at the fiber tip mirror), one can take any of two ways including, but not limited to: 1. carrying out hydrofluoric acid (HF) corrosion on the surface of the optical fiber to enable the surface to be atomized and the smooth surface to be roughened, and damaging the circular interface between the optical fiber and the adjacent medium to achieve the aim of injection or transmission, wherein the effect is similar to that of ground glass; 2. the circular interface is ground to be a plane or a polygon, and light can be emitted or transmitted, as shown in fig. 3, the circular shape of the optical fiber interface at the position d is only required to be damaged, and the light can be totally reflected in the optical fiber to be emitted or transmitted whether the circular interface is ground, atomized or formed into other shapes (prisms).

Fig. 4 is a flowchart showing steps of a method for manufacturing a brain tissue blood oxygen saturation detection device according to the present invention. As shown in fig. 4, the preparation method of the brain tissue blood oxygen saturation detection device of the invention comprises the following steps:

and S1, precisely cutting or grinding the tips of a plurality of optical fibers to form an inclined plane with a certain angle, and carrying out gold plating or other metals on the inclined plane to form a mirror surface.

In an embodiment of the invention, the angle of each fiber tip slope is between 0 ° -90 ° (here, 0 ° and 90 ° are not included, because at 0 ° the reflecting mirror surface is almost parallel to the incident light, and the diffuse reflected light cannot be reflected after entering the fiber; 90 °, and the fiber cannot be processed). Specific angle values need to be designed according to the optical fiber processing and practical application scenes. Generally, at 45 degrees, the light enters the light, the light can be conducted along the long axis of the light through specular reflection, the theoretical attenuation is minimum, the maximum detection light intensity can be obtained, and the detection is more sensitive, so in the specific embodiment of the invention, the tips of the two optical fibers A and B are precisely cut or ground by taking the two optical fibers A and B as examples, the angle of the formed tip inclined plane (M and N) is 45 degrees, and gold plating or other metals are carried out at the inclined plane (M and N) to form a mirror surface. Coatings or other modifications may also be made on the exterior of the metal as necessary to provide biocompatibility for use in brain tissue.

And S2, arranging the optical fibers side by side and fixing the optical fibers with each other, wherein one optical fiber serves as an outgoing optical fiber, the other optical fibers serve as incoming optical fibers, and each incoming optical fiber is separated from an outgoing tip by a certain distance. In a specific embodiment of the present invention, the optical fibers are fixed by means of bonding or the like. If necessary, the optical fiber can be provided with a heat-shrinkable tube, a coating and the like outside, so that the surface is regular, and the position relation of the optical fiber in the optical fiber can be kept fixed.

In the embodiment of the present invention, the two optical fibers (a, B) are taken as an example, the optical fibers a, B are arranged side by side, the tips are spaced apart by a certain distance, and the fixation is performed by bonding or the like, where a is an incoming optical fiber, B is an outgoing optical fiber, and the distance between the two mirrored tips of the incoming optical fiber a and the outgoing optical fiber B depends on the requirement of the 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, and the relation between the specific distance parameter and the detection range can be calculated according to a parabolic fitting formula, which is disclosed in the literature of the prior art and is not described herein.

Preferably, in order that the optical signal transmitted into the optical fiber can be smoothly emitted out of the optical fiber, and that the optical signal reflected by brain tissue can be smoothly transmitted into the outgoing optical fiber, it is necessary to avoid the total reflection of light. Therefore, in step S1, the optical fiber tip needs to be processed into a prism or a four-sided cubic prism by grinding or the like. Generally, the optical fiber is used to transmit light in a glass material without transmitting through the material, which means that the optical fiber cannot pass through a circular interface between the optical fiber and the surrounding air or other substances due to the principle of total reflection. Thus, where each fiber is required to be ejected or launched (i.e., at the fiber tip mirror), one can take any of two ways including, but not limited to: 1. carrying out hydrofluoric acid (HF) corrosion on the surface of the optical fiber to enable the surface to be atomized and the smooth surface to be roughened, and damaging the circular interface between the optical fiber and the adjacent medium to achieve the aim of injection or transmission, wherein the effect is similar to that of ground glass; 2. the circular interface is ground to become a plane or a polygon, and light can be emitted or transmitted.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is to be indicated by the appended claims.

Claims

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:

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.