CN115530817A - Method and device for measuring central venous blood oxygen saturation - Google Patents

Abstract

A measuring device and measuring method for central venous blood oxygen saturation, the measuring device includes a central venous catheter, a first wafer arranged on the central venous catheter, a second wafer and an optoelectronic device for collecting optical signals, the first The first wafer and the second wafer are respectively used to emit at least two channels of light with different wavelengths to the blood to be tested to obtain a corresponding first light intensity ratio and a second light intensity ratio, and the signal processing circuit is used to The blood oxygen saturation of the blood to be measured is obtained by calculating the ratio of the light intensity to the second light intensity ratio; among the light emitted by the first wafer and the second wafer, the value of the optical signal intensity corresponding to at least one light is smaller than the light corresponding to the other light. The value of the signal intensity to increase at least one light intensity ratio to be obtained. The measurement method above improves the measurement accuracy of the blood oxygen saturation by increasing at least one light intensity ratio to be obtained.

Description

Method and device for measuring central venous blood oxygen saturation

technical field

The invention relates to the technical field of medical machinery, in particular to a measuring method and measuring device for central venous blood oxygen saturation.

Background technique

Blood oxygen saturation (SaO ₂ ) is the percentage of the capacity of oxygen-bound oxyhemoglobin (HbO ₂ ) in the blood to the total hemoglobin (Hb, hemoglobin) capacity that can be combined, that is, the concentration of blood oxygen in the blood, which is the breath Important physiological parameters of circulation. Wherein, central venous blood oxygen saturation (ScvO ₂ ) is blood oxygen saturation measured by a central venous catheter. Using a specific device in the central venous catheter to directly measure the oxygen saturation of venous blood has the advantages of not increasing any risk for the patient, easy to operate, and economical and applicable. When using a central venous catheter to measure blood oxygen saturation, a device containing ScvO ₂ can be used to continuously monitor ScvO ₂ , so that it can dynamically reflect the oxygen supply and oxygen consumption level of tissues and organs, and accurately evaluate whether the cell function and internal environment are stable , so as to guide clinical treatment to avoid tissue hypoxia and subsequent organ failure, and also to establish the effectiveness of treatment measures and judge prognosis according to the change of ScvO ₂ , therefore, using central venous catheter to measure central venous oxygen saturation It has irreplaceable clinical value.

The existing central venous oxygen saturation measurement method is mainly to install an optical fiber through the cavity of the medical device in the central venous catheter. The optical fiber is in contact with the blood at the end of the central venous catheter. Red light and infrared light are emitted, reflected by cells, and then the receiving optical fiber in the optical fiber performs digital processing on the received light intensity, and then calculates ScvO ₂ . However, since factors such as blood flow velocity and Hct value (hematocrit) have a great influence on ScvO ₂ , when the patient's state fluctuates greatly, the measurement results need to be calibrated. Since the light intensity reflected by red blood cells in the body is much smaller than the light intensity emitted to red blood cells, the light intensity received by the receiving optical fiber is not only affected by the different absorption characteristics of oxygenated hemoglobin and reduced hemoglobin, but also by Affected by many factors, such as blood flow velocity, blood pH and hematocrit (Hct), etc. Especially at low oxygen saturation, Hct has a great influence on the measured value, how to further improve the measurement accuracy of central venous blood oxygen saturation is one of the problems to be solved or improved at present.

Contents of the invention

According to a first aspect, an embodiment discloses a device for measuring central venous blood oxygen saturation, comprising:

a central venous catheter having a distal end for insertion into a central vein, the central venous catheter comprising a lumen;

The first wafer, located on the outer wall of the cavity, is used to emit at least two lines of light with different wavelengths to the blood to be tested, and the at least two lines of light are used to form optical signals reflected by the blood to be tested, and the at least two lines of light The light is used to obtain a first light intensity ratio through the ratio of the respective light signal intensities;

The second wafer, located on the inner wall of the cavity, is used to emit at least two lines of light with different wavelengths to the blood to be tested, and the at least two lines of light are used to pass through the blood to be tested to form optical signals, and the at least two lines of light The light is used to obtain a second light intensity ratio through the ratio of the respective light signal intensities;

An optoelectronic device, including a first sensor located on the outer wall of the cavity and a second sensor on the inner wall of the cavity, the first sensor is arranged side by side with the first wafer, and is used to collect and output the blood to be tested The optical signal formed by reflection, the second sensor is arranged opposite to the second wafer, and is used to collect and output the optical signal formed after being transmitted through the blood to be measured;

A signal processing circuit, which is respectively coupled to the output ends of the first sensor and the second sensor, for receiving and processing the light signals output by the first sensor and the second sensor, to obtain the first light intensity ratio and the second light intensity ratio , and used to calculate the blood oxygen saturation of the blood to be measured according to the first light intensity ratio and the second light intensity ratio; wherein, among the light rays emitted by the first wafer and the second wafer, at least one path of light corresponds to The value of the optical signal intensity of the light is smaller than the value of the optical signal intensity corresponding to the light of other paths, so as to increase at least one light intensity ratio to be obtained.

According to the second aspect, an embodiment provides a method for measuring central venous blood oxygen saturation, comprising:

emitting at least two light beams with different wavelengths to the blood to be measured in the central vein;

Obtaining light signals obtained after at least two paths of light have passed through the blood to be tested, and the at least two paths of light are used to obtain at least one light intensity ratio through the ratio of the respective light signal intensities;

calculating the ratio of the optical signal intensity of the light with a longer wavelength to the light with a smaller wavelength among the at least two paths of light, so as to increase at least one light intensity ratio to be obtained;

The blood oxygen saturation of the blood to be tested is calculated according to at least one light intensity ratio.

According to a third aspect, an embodiment provides a device for measuring central venous blood oxygen saturation, comprising:

A central venous catheter, the end of which is inserted into a central vein:

a wafer positioned at the end of the central venous catheter for emitting at least one path of light to the blood to be tested;

A photoelectric device, located at the end of the central venous catheter, is used to receive the at least one path of light after being acted on by the blood to be tested, so as to obtain at least one light signal;

The signal processing circuit is signal-connected with the photoelectric device, and is used to calculate the blood oxygen saturation of the blood to be measured according to the intensity of at least one light signal.

In the above embodiment, at least two lines of light with different wavelengths are emitted to the blood to be tested in the central venous catheter, and the ratio of the optical signal intensity of the light with a larger wavelength to the light with a smaller wavelength among the at least two lines of light is calculated to increase At least one light intensity ratio is to be obtained, and then the central venous blood oxygen saturation is calculated according to the at least one light intensity ratio. In the calculation of central venous blood oxygen saturation, the greater the light intensity ratio, the lower the blood oxygen saturation of the same blood to be measured and is close to the real value, so the above method improves the measurement accuracy of central venous blood oxygen saturation.

Description of drawings

Fig. 1 is a schematic structural view of a central venous catheter of an embodiment;

Fig. 2 is a schematic diagram of a first base of an embodiment;

Fig. 3 is a schematic diagram of a second base of an embodiment;

Fig. 4 is a schematic diagram of a third base of an embodiment;

Fig. 5 is a schematic diagram of a signal processing circuit of an embodiment;

Fig. 6 is a schematic diagram of a calculation processing circuit of an embodiment;

Fig. 7 is a flow chart of a method for measuring central venous blood oxygen saturation in an embodiment;

100. Central venous catheter;

110, cavity; 120, first base; 130, second base; 140, third base;

200. The first wafer;

300. The second wafer;

410. The first sensor;

420. The second sensor;

500. Signal processing circuit;

510. Signal amplification/conditioning circuit; 520. Analog-to-digital conversion circuit; 530. Calculation processing circuit.

detailed description

The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings. Wherein, similar elements in different implementations adopt associated similar element numbers. In the following implementation manners, many details are described for better understanding of the present application. However, those skilled in the art can readily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the application are not shown or described in the description, this is to avoid the core part of the application being overwhelmed by too many descriptions, and for those skilled in the art, it is necessary to describe these operations in detail Relevant operations are not necessary, and they can fully understand the relevant operations according to the description in the specification and general technical knowledge in the field.

In addition, the characteristics, operations or characteristics described in the specification can be combined in any appropriate manner to form various embodiments. At the same time, the steps or actions in the method description can also be exchanged or adjusted in a manner obvious to those skilled in the art. Therefore, various sequences in the specification and drawings are only for clearly describing a certain embodiment, and do not mean a necessary sequence, unless otherwise stated that a certain sequence must be followed.

The serial numbers assigned to components in this document, such as "first", "second", etc., are only used to distinguish the described objects, and do not have any sequence or technical meaning. The "connection" and "connection" mentioned in this application all include direct and indirect connection (connection) unless otherwise specified.

The most important idea of the present invention is: ① calculate the oxygen saturation of the central venous blood through the light intensity ratio, and emit at least one light with a smaller wavelength, so as to improve the measurement accuracy; ② use the wafer as the light-emitting element, thereby reducing the error; ③ The transmission blood oxygen saturation measurement method and the reflective blood oxygen saturation measurement method are combined to further improve the measurement accuracy.

Please refer to Fig. 1 to Fig. 5, present embodiment provides a kind of central venous blood oxygen saturation measuring device, this measuring device comprises central venous catheter 100, first wafer 200, second wafer 300, optoelectronic device and signal processing circuit 500 .

The central venous catheter 100 is a type of intravascular tube, and the end thereof is inserted into a central vein and comes into contact with blood. In the prior art, the central venous catheter 100 may have one or more lumens 110 , hereinafter, the central venous catheter 100 has a single lumen 110 as an example for illustration.

The first wafer 200 is located on the outer wall of the cavity 110, and the first wafer 200 is used to emit two paths of light with different wavelengths to the blood to be tested. In other embodiments, the first wafer 200 may also emit more than two paths of light, that is, the first wafer 200 may emit at least two paths of light in this application. As shown in FIGS. 1 to 2 , a first base 120 is installed on the outer wall of the cavity 110 , and two first wafers 200 are installed on the first base 120 . In this embodiment, the wavelength of one path of light emitted by the first wafer 200 is λ1, and the wavelength of another path of light emitted by the first wafer 200 is λ2. The two paths of light are used to reflect from the blood to be measured to form two light signals collected by the photoelectric device.

The second wafer 300 is located on the inner wall of the cavity 110 and is used for emitting two paths of light with different wavelengths to the blood to be tested. In other embodiments, the second wafer 300 may also emit more than two paths of light, that is to say, the second wafer 300 may emit at least two paths of light in this application. As shown in FIGS. 1 and 3 , a second base 130 is installed on the inner wall of the cavity 110 , and two second wafers 300 are installed on the second base 130 . In this embodiment, the wavelength of one path of light emitted by the second wafer 300 is λ3, and the wavelength of another path of light emitted by the second wafer 300 is λ4. Two paths of light are used to pass through the blood to be tested to form light signals collected by the photoelectric device.

The optoelectronic device includes a first sensor 410 located on the outer wall of the cavity 110 and a second sensor 420 located on the inner wall of the cavity 110 . As shown in Figure 2, the first sensor 410 is also installed on the first base 120, the first sensor 410 is arranged side by side with the first wafer 200, and the first sensor 410 is used to collect and output to the signal processing circuit 500 the tested The light signal formed by blood reflection, that is to say, the light emitted by the first wafer 200 will not only pass through the blood to be tested, but also be reflected by the blood to be tested. The first sensor 410 only collects the light signal formed by the blood reflection. . The second sensor 420 is arranged opposite to the second wafer 300. For example, as shown in FIGS. Installed on the third base 140, the second sensor 420 is used to collect and output to the signal processing circuit 500 the optical signal formed after being transmitted through the blood to be measured, that is to say, the light emitted by the second wafer 300 will pass through the The blood to be tested is also reflected by the blood to be tested, and the second sensor 420 only collects the light signal formed through the blood.

The existing central venous blood oxygen saturation measuring device is mainly to install the emitting optical fiber and the receiving light in the cavity 110 of the central venous catheter 100, and the emitting optical fiber is in contact with the blood and periodically emits red light and infrared light, and the emitted The light is reflected by the cells and then received by the receiving optical fiber. Since the blood flows in the blood vessel in the form of pulsation, the optical fiber in the central venous catheter 100 will also move uncontrollably, thereby affecting the light intensity received by the receiving optical fiber.

Compared with the existing central venous blood oxygen saturation measuring device, the structure of the measuring device of the present application has the following advantages:

(1) The wafer is used as the light emitting element. The volume of the wafer is small, so that the light-emitting element in the measuring device can be directly placed at the end of the central venous catheter 100, that is, the first wafer 200 above is located on the outer wall of the cavity 110, and the second wafer 300 is located on the outer wall of the cavity 110. The inner wall of the body 110. Since the light-emitting element is arranged on the central venous catheter 100, there will be no uncontrolled swing, thereby preventing the light intensity received by the photoelectric device from being affected and causing subsequent calculation errors of central venous blood oxygen saturation.

(2) The transmissive blood oxygen measurement method and the reflective blood oxygen measurement method are combined in the same measuring device, thereby further reducing the error that may be caused by a single measurement method.

The signal processing circuit 500 is respectively coupled to the output ends of the first sensor 410 and the second sensor 420, and is used for receiving and processing the light signals output by the first sensor 410 and the second sensor 420, and the signal processing circuit 500 is used for The first light intensity ratio is obtained from the optical signal intensity of the light emitted by the wafer 200 , and the second light intensity ratio is obtained according to the optical signal intensity of the light emitted by the second wafer 300 . Then, the signal processing circuit 500 calculates the oxygen saturation of the blood to be measured according to the first light intensity ratio and the second light intensity ratio. Among the light beams emitted by the first wafer 200 and the second wafer 300 , the value of the optical signal intensity corresponding to at least one line of light is smaller than the value of the optical signal intensity corresponding to other lines of light. Take the light rays with wavelengths λ1 and λ2 emitted by the first wafer 200 and the light rays with wavelengths λ3 and λ4 emitted by the second wafer 300 as an example above. Wherein, the optical signal intensity of light with wavelength λ1 is I1, the optical signal intensity of light with wavelength λ2 is I2, the optical signal intensity of light with wavelength λ3 is I3, and the optical signal intensity of light with wavelength λ4 is I4, The relationship between the four optical signal intensities can be I1>I2 and I3>I4, then the first light intensity ratio can be: I1/I2, and the second light intensity ratio can be: I3/I4, where I3 can be equal to I2, or I4 Can be equal to I2.

Through the setting of the above optical signal intensity, the signal processing circuit 500 can increase the obtained light intensity ratio. After theoretical and practical verification, the increase of the light intensity ratio can improve the measurement accuracy under low oxygen saturation, thereby improving the central venous Measurement accuracy of blood oxygen saturation. The above-mentioned method of calculating the blood saturation based on the ratio of light intensity may adopt an existing algorithm or an algorithm that may appear in the future.

In some embodiments, the wavelength of at least one line of light emitted by the first wafer 200 and/or the second wafer 300 is smaller than the wavelength of other lines of light, and the signal processing circuit 500 is also used to calculate at least two lines of light from the same wafer The ratio of the optical signal intensity of light with a longer wavelength to light with a smaller wavelength in order to increase the desired light intensity ratio. For example, among the light rays emitted by the first wafer 200 and the second wafer 300 , λ1 is respectively smaller than λ2 , λ3 and λ4 , then the first light intensity ratio may be: I2/I1.

The measurement device in the above embodiment emits at least one low-wavelength light signal. After theoretical and practical verification, in cell biology, oxyhemoglobin and reduced hemoglobin absorb light with a smaller wavelength to a greater extent, and the signal processing circuit The 500 determines the calculation method of the light intensity ratio according to the wavelength, which can increase the desired light intensity ratio.

In some embodiments, as shown in FIG. 5 (the coupling of the signal processing circuit 500 and the second sensor 420 is shown in this figure), the signal processing circuit 500 includes a signal amplification/conditioning circuit 510, an analog-to-digital conversion circuit 520 and calculation processing circuit 530 .

The signal amplification/conditioning circuit 510 is connected to the output terminals of the first sensor 410 and the second sensor 420 respectively. After the first sensor 410 and the second sensor 420 collect the optical signal, the optical signal is sent to the signal amplification/conditioning circuit 510 in the form of an electrical signal, and the signal amplification/conditioning circuit 510 can amplify the electrical signal and perform other processing ( Other processing such as filtering), the analog-to-digital conversion circuit 520 performs analog-to-digital conversion on the amplified signal, and then outputs it to the calculation processing circuit 530 .

A kind of specific structure of calculation processing circuit 530 is shown in Figure 6, and this calculation processing circuit 530 comprises a plurality of dividers (1a, 2a, 3a and 4a), multiplier (1b and 2b), amplifier (1c, 2c, 3c , 4c, 5c, 6c, 7c, 8c, 9c and 10c), adders (1f, 2f, 3f and 4f) and other necessary electronic components. In this figure, the analog-to-digital conversion circuit 520 outputs the optical signal intensity I1 and the optical signal intensity I2 to the divider 1a, and outputs the optical signal intensities I3 and I4 to the divider 2a, wherein the optical signal intensity I1 corresponds to the wavelength λ1 of the light that is greater than the light The signal intensity I2 corresponds to the wavelength λ2 of the light, and the optical signal intensity I3 corresponds to the wavelength λ3 of the light greater than the optical signal intensity I4 corresponds to the wavelength λ4 of the light. The first light intensity ratio can be obtained by using the divider 1a, and the first light intensity ratio is: I1/I2. The second light intensity ratio can be obtained by using the divider 2a, and the second light intensity is I3/I4.

The signal output from the divider 1a is applied to the multiplier 1b to obtain the square of the first light intensity ratio, and the signal output from the divider 2a is applied to the multiplier 2b to obtain the square of the second light intensity ratio. Amplifier 1c processes the signal output from multiplier x with appropriate gain and calibration coefficient A2 to obtain signal A2(I1/I2) ² , and similarly, amplifier 2c processes the signal output from multiplier with calibration coefficient B2 to obtain Obtain signal B2(I1/I2) ² , similarly, amplifier 3c and amplifier 4c amplify the first light intensity ratio with appropriate gain and calibration coefficients A1 and B1 respectively, and obtain signal A1(I1/I2) and signal B1(I1/I2). Similarly, amplifier 5c, amplifier 6c, amplifier 7c and amplifier 8c respectively output signals C2(I3/I4) ² , D2(I3/I4) ² , C1(I3/I4) and D1(I3/I4). The voltage source 1d acts together with the resistors 1e and 2e to generate the signal A0. An output signal is then generated at the adder 1f: A0+A1(I1/I2)+A2(I1/I2) ² . Similarly, use adder 2f, adder 3f, adder 4f and adder 5f to generate output signals respectively: B0+B1(I1/I2)+B2(I1/I2) ² , C0+C1(I3/I4)+ C2(I3/I4) ² and D0+D1(I3/I4)+D2(I3/I4) ² .

Further output the first blood oxygen saturation calculation value through the divider 3a, and output the second blood oxygen saturation calculation value through the divider 4a, wherein the first blood oxygen saturation calculation value is:

The calculated value of the second blood oxygen saturation is:

After obtaining the first blood oxygen saturation calculation value and the second blood oxygen saturation calculation value, the signal processing circuit 500 further performs the first blood oxygen saturation calculation value and the second blood oxygen saturation calculation value through the amplifier 9c and the amplifier 10c. The weighted average is used to obtain the blood oxygen saturation of the blood to be tested. In Figure 6, the central venous oxygen saturation is:

Wherein Q1 and Q2 are weight coefficients of the first blood oxygen saturation calculation value and the second blood oxygen saturation calculation value respectively, and the sum of Q1 and Q2 is 1. In some embodiments, the weight coefficient is determined based on the historical trend of the blood oxygen saturation of the blood to be measured. For example, after multiple measurements, the measuring device can obtain the real average value of the historical trend, and if the calculated blood oxygen saturation value differs greatly from the real average value, the weight coefficient will be small.

The signal processing circuit 500 with the above-mentioned structure can eliminate measurement errors caused by various factors as much as possible by performing weighted average of each calibration coefficient and the obtained blood oxygen saturation calculation value, so as to obtain more accurate measurement results.

Please refer to Fig. 7, the present invention also provides a method for measuring central venous oxygen saturation, comprising steps:

Step S10 , emitting at least two paths of light rays with different wavelengths to the blood to be measured in the central vein.

In this step, the existing emitting optical fiber can be used to emit the above-mentioned light with different wavelengths, or the wafer in the previous embodiment can be used to emit light with different wavelengths.

Step S20 , acquiring light signals obtained after at least two paths of light have passed through the blood to be tested, and the at least two paths of light are used to obtain at least one light intensity ratio through the ratio of the respective light signal intensities.

In this step, the light signal obtained by the blood to be tested refers to the light signal obtained after passing through the blood to be tested, or the light signal obtained after being reflected by the blood to be tested. In some embodiments, the optical signal obtained by the action of the blood to be tested includes not only the optical signal obtained after passing through the blood to be tested, but also the optical signal obtained after being reflected by the blood to be tested, so that the transmissive and reflective Combined with the method of obtaining blood oxygen saturation, more accurate measurement results can be obtained.

Step S30 , calculating the ratio of the optical signal intensity of the light with a longer wavelength to the light with a smaller wavelength among the at least two paths of light, so as to increase at least one light intensity ratio to be obtained.

In some embodiments, in step S10, one path of light with a wavelength of λ1 and another path of light with a wavelength of λ2 are emitted to the blood to be tested, wherein, λ1>λ2, the optical signal intensity of the light with a wavelength of λ1 is I1, and its wavelength is λ2 The light signal intensity of the light rays is I2, and the light intensity ratio obtained from the two light rays is: I1/I2.

In some other embodiments, in addition to the above-mentioned light rays with wavelengths λ1 and λ2, light with a wavelength of λ3 is also emitted to the blood to be tested in step S10, the corresponding optical signal intensity of this light is I3, and there is a relationship: λ1 >λ2>λ3. Then, the light intensity ratio obtained according to the three light rays may include two other light intensity ratios: I1/I3 and I2/I3 in addition to the above-mentioned I1/I2.

How to obtain the corresponding light intensity ratio when there are more light paths can be deduced reasonably from the above two examples, and will not be repeated here.

Step S40, calculating the blood oxygen saturation of the blood to be tested according to at least one light intensity ratio.

In this step, an existing algorithm or an algorithm that may appear in the future may be used for the method of calculating the blood saturation according to the light intensity ratio.

In some embodiments, when light rays of different wavelengths include at least three paths, the light rays of at least three paths can form at least N light groups, where N is greater than or equal to 2, and each light group can obtain a corresponding light intensity ratio , the light intensity ratio corresponding to each light group is the ratio of the optical signal intensity of the light with a larger wavelength to the light with a smaller wavelength in the light group. Then one way to calculate the central venous oxygen saturation is:

First, the corresponding blood oxygen saturation calculation value is calculated according to each light intensity ratio, and then the N blood oxygen saturation calculation values are weighted and averaged to obtain the blood oxygen saturation of the blood to be measured.

Specifically, the formula for obtaining the corresponding blood oxygen saturation calculation value according to the i-th light intensity ratio is as follows:

Among them, Si is the blood oxygen saturation calculation value obtained according to the i-th light intensity ratio, i is greater than or equal to 1 and less than or equal to N, and A _i0 , A _i1 , A _i2 , B _i0 , B _i1 and B _i2 are preset Calibration coefficients, each calibration coefficient can be obtained through clinical trials. R _i is the i-th light intensity ratio, and the calculation formula of the i-th light intensity ratio is as follows:

Among them, I _i1 is the light intensity obtained after the light with a larger wavelength in the i-th light group reacts with the blood to be tested, and I _i2 is the light obtained after the light with a smaller wavelength in the i-th light group reacts with the blood to be tested powerful. Then, the above S is weighted and averaged to finally obtain the blood oxygen saturation of the blood to be measured. For example, the final obtained central venous oxygen saturation can be obtained by the following formula:

Among them, ScvO ₂ is the central venous blood oxygen saturation, and Qi is the weight coefficient corresponding to the i-th blood oxygen saturation calculation value. In some embodiments, the weight coefficient is determined based on the historical trend of the blood oxygen saturation of the blood to be measured. For example, after multiple measurements, the measuring device can obtain the real average value of the historical trend, and if the calculated blood oxygen saturation value differs greatly from the real average value, the weight coefficient will be small.

The above embodiments improve the measurement accuracy of the central venous blood oxygen saturation by increasing the light intensity ratio. In addition, the wafer is used as the light emitting element, and the transmission measurement and the reflection measurement are combined to further reduce the measurement error, thereby reducing the Number of calibrations or no subsequent recalibration required.

Those skilled in the art can understand that all or part of the functions of the various methods in the foregoing implementation manners can be realized by means of hardware, or by means of computer programs. When all or part of the functions in the above embodiments are implemented by means of a computer program, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, magnetic disk, optical disk, hard disk, etc., through The computer executes the program to realize the above-mentioned functions. For example, the program is stored in the memory of the device, and when the processor executes the program in the memory, all or part of the above-mentioned functions can be realized. In addition, when all or part of the functions in the above embodiments are realized by means of a computer program, the program can also be stored in a storage medium such as a server, another computer, a magnetic disk, an optical disk, a flash disk, or a mobile hard disk, and saved by downloading or copying. To the memory of the local device, or to update the version of the system of the local device, when the processor executes the program in the memory, all or part of the functions in the above embodiments can be realized.

The above uses specific examples to illustrate the present invention, which is only used to help understand the present invention, and is not intended to limit the present invention. For those skilled in the technical field to which the present invention belongs, some simple deduction, deformation or replacement can also be made according to the idea of the present invention.

Claims (11)

1. A device for measuring central venous blood oxygen saturation, comprising:

a central venous catheter having a distal end for insertion into a central vein, the central venous catheter comprising a lumen;

the first wafer is positioned on the outer wall of the cavity and used for emitting at least two paths of light rays with different wavelengths to blood to be detected, the at least two paths of light rays are used for forming optical signals through reflection of the blood to be detected, and the at least two paths of light rays are used for obtaining a first light intensity ratio through the ratio of the respective optical signal intensities;

the second wafer is positioned on the inner wall of the cavity and used for emitting at least two paths of light rays with different wavelengths to blood to be detected, the at least two paths of light rays are used for forming optical signals through the blood to be detected, and the at least two paths of light rays are used for obtaining a second light intensity ratio through the ratio of the respective optical signal intensities;

the photoelectric device comprises a first sensor and a second sensor, the first sensor is positioned on the outer wall of the cavity body, the second sensor is positioned on the inner wall of the cavity body, the first sensor and the first wafer are arranged in parallel and used for collecting and outputting optical signals formed by reflection of blood to be detected, and the second sensor and the second wafer are arranged oppositely and used for collecting and outputting optical signals formed by transmission of the blood to be detected;

the signal processing circuit is respectively coupled to the output ends of the first sensor and the second sensor, and is used for receiving and processing the optical signals output by the first sensor and the second sensor to obtain a first light intensity ratio and a second light intensity ratio and calculating the blood oxygen saturation of the blood to be detected according to the first light intensity ratio and the second light intensity ratio; among the light rays emitted by the first wafer and the second wafer, the value of the optical signal intensity corresponding to at least one path of light ray is smaller than the values of the optical signal intensities corresponding to other paths of light rays, so that at least one light intensity ratio to be obtained is increased.

2. The measurement apparatus according to claim 1, wherein the wavelength of at least one of the light beams emitted from the first wafer and/or the second wafer is smaller than the wavelengths of the other light beams, and the signal processing circuit is further configured to increase the ratio of the optical signal intensities of the light beams with the larger wavelength and the light beams with the smaller wavelength in the at least two light beams of the same wafer, so as to increase the ratio of the light intensities to be obtained.

3. The measuring device according to claim 1, wherein calculating the blood oxygen saturation level of the blood to be measured according to the first light intensity ratio and the second light intensity ratio comprises:

calculating a first blood oxygen saturation calculation value according to the first light intensity ratio;

calculating a second calculated value of the blood oxygen saturation according to the second light intensity ratio; and

and carrying out weighted average on the first blood oxygen saturation calculation value and the second blood oxygen saturation calculation value to obtain the blood oxygen saturation of the blood to be detected.

4. A central venous blood oxygen saturation measurement method is characterized by comprising the following steps:

emitting at least two paths of light rays with different wavelengths to blood to be detected in the central vein;

obtaining optical signals obtained by at least two paths of light rays after the action of blood to be detected, wherein the at least two paths of light rays are used for obtaining at least one light intensity ratio through the ratio of the respective optical signal intensities;

calculating the ratio of the optical signal intensity of the light with larger wavelength to the optical signal intensity of the light with smaller wavelength in the at least two paths of light so as to increase at least one light intensity ratio to be obtained;

and calculating the blood oxygen saturation of the blood to be detected according to at least one light intensity ratio.

5. The method of claim 4, wherein the light of different wavelengths emitted toward the blood under test comprises at least three light rays, the at least three light rays being used to form at least two light ray groups, each light ray group comprising two light rays of different wavelengths, each light ray group being used to obtain an intensity ratio, the method further comprising:

calculating the ratio of the light signal intensity of the light with larger wavelength to the light with smaller wavelength in the at least two light ray groups so as to increase the at least two light intensity ratios to be obtained;

and calculating the blood oxygen saturation of the blood to be detected according to the at least two light intensity ratios.

6. The method of claim 5, wherein calculating the blood oxygen saturation level of the blood to be measured from the at least two intensity ratios comprises:

calculating at least two calculated values of the blood oxygen saturation according to at least two light intensity ratios, wherein one calculated value of the blood oxygen saturation is obtained based on one light intensity ratio;

and carrying out weighted average on the at least two calculated values of the blood oxygen saturation to obtain the blood oxygen saturation of the blood to be detected.

7. The method of claim 6, wherein in the weighted averaging to obtain the blood oxygen saturation, the weight coefficient of each calculation value of the blood oxygen saturation is determined based on a historical trend of the blood oxygen saturation of the blood to be measured.

8. The method of claim 6, wherein the calculated value of the blood oxygen saturation is obtained from the ith intensity ratio by the following formula:

wherein Si is a calculated value of the oxygen saturation of blood obtained from the ith light intensity ratio, i is not less than 1 and not more than the number of the obtained light intensity ratios, A _i0 、A _i1 、A _i2 、B _i0 、B _i1 And B _i2 Respectively, a preset calibration coefficient, R _i For the ith light intensity ratio, the calculation formula of the ith light intensity ratio is as follows:

wherein, I _i1 The light intensity, I, of the light with larger wavelength in the ith light group after the blood to be measured acts _i2 The light intensity of the light with smaller wavelength in the ith light group is obtained after the light with smaller wavelength is acted by the blood to be measured.

9. The method according to claim 5, wherein at least one of the at least two light beams with different wavelengths is used for transmitting the blood to be measured to form an optical signal, and at least one of the at least two light beams is used for reflecting the blood to be measured to form an optical signal.

10. The method of claim 4, wherein emitting at least two different wavelengths of light to the blood to be measured in the central vein comprises:

and emitting two paths of light rays with different wavelengths to the blood to be detected in the central vein by using the wafer at the tail end of the central venous catheter inserted into the central vein.

11. A central venous oxygen saturation measurement device, comprising:

a central venous catheter, the end of which is for insertion into a central vein:

the wafer is positioned at the tail end of the central venous catheter and used for emitting at least one path of light to blood to be detected;

the photoelectric device is positioned at the tail end of the central venous catheter and used for receiving the at least one path of light acted by the blood to be detected so as to obtain at least one optical signal;

and the signal processing circuit is in signal connection with the photoelectric device and is used for calculating the blood oxygen saturation of the blood to be measured according to the intensity of at least one optical signal.

Images