CN110547808B - Blood oxygen measuring device and system and blood oxygen signal detecting method thereof - Google Patents
Blood oxygen measuring device and system and blood oxygen signal detecting method thereof Download PDFInfo
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- CN110547808B CN110547808B CN201910906425.1A CN201910906425A CN110547808B CN 110547808 B CN110547808 B CN 110547808B CN 201910906425 A CN201910906425 A CN 201910906425A CN 110547808 B CN110547808 B CN 110547808B
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 155
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 155
- 239000001301 oxygen Substances 0.000 title claims abstract description 155
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- 238000002496 oximetry Methods 0.000 claims description 17
- 238000001514 detection method Methods 0.000 claims description 16
- 238000001303 quality assessment method Methods 0.000 claims description 9
- 230000008569 process Effects 0.000 abstract description 7
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- 238000002106 pulse oximetry Methods 0.000 description 2
- 230000000241 respiratory effect Effects 0.000 description 2
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- 241001465754 Metazoa Species 0.000 description 1
- 108010064719 Oxyhemoglobins Proteins 0.000 description 1
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Classifications
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
- A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
- A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
- A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
- A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
- A61B5/14557—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases specially adapted to extracorporeal circuits
Abstract
The blood oxygen measuring device and system and the blood oxygen signal detecting method comprise at least four photoelectric amplifying circuits; the main control module sequentially and respectively accesses the four photoelectric amplifying circuits to obtain four measuring signals, wherein the photoelectric amplifying circuit with the measuring signal of 700-900 millivolts is selected to be used as a subsequent measuring photoelectric amplifying circuit. When the four measurement signals are not between 700 and 900 millivolts, the output power of the light source is adjusted to be N times or 1/N times of the previous output power until the measurement signal of at least one photoelectric amplifying circuit is between 700 and 900 millivolts. The method of combining multipath photoelectric amplification and optical drive adjustment is adopted, and the amplification factor and bias of a later amplifying circuit are set according to the method, so that the circuit is quickly adapted to external measurement conditions, the adaptation process between an optical signal and the external measurement conditions is greatly shortened, and therefore, quick blood oxygen measurement is realized, and especially, the initial blood oxygen response time is far superior to that of the prior art.
Description
Technical Field
The invention relates to the technical field of medical equipment, in particular to an oxygen measuring device, an oxygen measuring system and an oxygen signal detection method for pulse oxygen measurement by utilizing red light and infrared light.
Background
Blood oxygen saturation (SpO 2) is the percentage of the volume of oxyhemoglobin (HbO 2) bound by oxygen in the blood to the volume of total hemoglobin (Hb) bound, i.e. the concentration of blood oxygen in the blood, which is an important physiological parameter of the respiratory cycle. Monitoring arterial oxygen saturation (SaO 2) allows an estimate of the oxygenation of the lung and the oxygen carrying capacity of hemoglobin. The blood oxygen saturation of normal human arterial blood is 98% and venous blood is 75%.
Pulse oximetry is a medical device that measures the oxygen content of a patient's arterial blood. Pulse oximeters provide a method for non-invasively measuring blood oxygen saturation or arterial hemoglobin saturation and for measuring the heart rate of a patient. Pulse oxygen monitoring is one of key parameters in modern clinical operations, intensive care, conventional monitoring and other applications, is widely applied, and can be applied to multi-parameter monitors, portable multi-parameter monitors and respiratory sleep monitors.
The pulse oximetry technique currently applied to the above-mentioned instruments is generally to alternately irradiate the region to be tested (typically, the tip of the circulation such as the fingertip, earlobe or forehead) with two light sources of visible red light spectrum (660 nm) and infrared light spectrum (940 nm), and the amount of light absorbed by the two light sources during the blood pulsation is related to the oxygen content in the blood, so that the change in the amount of light absorbed during the arterial pulsation is detected, and the ratio of the absorbed energy of the two spectra is calculated, and the result is compared with a saturation value table in a memory, thereby obtaining the blood oxygen saturation. The photoelectric driving light source and the photoelectric conversion circuit amplify and digitize the electric signal, and then perform digital signal processing calculation to obtain human body parameter indexes such as pulse oxygen saturation value, pulse rate, perfusion index and the like.
The blood oxygen measuring system in the prior art comprises measuring probes in two measuring modes, wherein the measuring probes comprise a reflection type blood oxygen probe and a transmission type blood oxygen probe; the reflection type blood oxygen probe is usually arranged on the body surface, and the blood oxygen saturation value is obtained by measuring the intensity of reflected light in the body surface and the tissue and performing contrast calculation; the transmission type blood oxygen probe is usually clamped on certain parts of a human body, such as the parts of fingers, toes, earlobes and the like, and after the light energy output by the two light sources passes through the parts of the human body, the transmitted light intensity is obtained for comparison calculation to obtain the blood oxygen saturation value. Because the characteristics of human body media have great differences, such as skin color, thickness of the measurement media and light transmission characteristics of the measurement media have great individual differences, the energy output by a light source in the blood oxygen measurement system needs to be well matched with the photoelectric detection capability of a subsequent circuit to obtain a good measurement result.
In the case of thin measurement media, such as thin fingers, earlobes, small animal tongues, neonatal palms, particularly weak perfusion, etc., no result is often measured due to the limited regulatory capacity of the system. In a system in which a probe part with partial light emission and a signal acquisition circuit are separated, the signal acquisition circuit is also generally required to be adjusted for different probes, so that the characteristic matching of a signal processing system and the probe becomes a great problem. The complexity of the signal processing system is also greatly increased if the circuit adjustment with respect to the large dynamic range of the measured object is performed on the basis of the circuit adjustment.
In the prior art, in order to realize the maximum dynamic range of signal amplification, the adjustment of driving a light source or the preliminary and slight staged adjustment (1, 2, 4, 8 times of gain) of signal gain is usually adopted, and the linkage gain adjustment often needs a long time and cannot realize quick response of output signals; the linkage gain adjustment cannot realize a larger dynamic range so as to adapt to different signal characteristics generated by different crowds and different measurement positions; in some critical situations, measurement is often failed due to failure of dynamic range adjustment, so that errors of measurement failure are generated, and application is affected.
In the prior art, a set of photoelectric output control circuit is generally adopted for red light and infrared light, and the red light and the infrared light are respectively driven through different driving combinations so as to adapt to different monitoring objects. The infrared and the red light share one set of driving circuit, so that the adjustment range of the driving of the light source is limited to a certain extent.
As shown in fig. 3, in the prior art, a first-stage photoelectric amplifying circuit is generally adopted, the photoelectric amplifying circuit is connected with an adjustable gain amplifying circuit, and means such as light source driving adjustment are combined to realize the adaptation of a measurement system to a medium to be measured and the signal intensity, and the first-stage photoelectric amplifying circuit enables the joint adjustment of the light source driving circuit, the first-stage amplifying circuit and the adjustable gain amplifying circuit to be a serial process, so that the adjustment speed is low, the adaptation range is not wide enough, and the condition of overshoot easily occurs, namely, the few extreme measurement conditions can exceed the adjustment range of the circuit.
Disclosure of Invention
In order to avoid the defects of the prior art, the invention provides a blood oxygen measuring device, a system and a blood oxygen signal detection method capable of rapidly measuring blood oxygen, the invention adopts a step-shaped amplifying circuit with parallel 4 circuits for amplifying performance and a light source driving circuit to cooperate, the driving and amplifying circuit multiple suitable for the current medium to be measured is rapidly found by sequentially round-robining each first-stage amplifying circuit, and the bias setting adjustment of the second-stage amplification is carried out by utilizing the signal output by the first-stage amplifying circuit, and the two are cooperated, so that the adaptation process between the optical signal and the medium to be measured by the system is greatly shortened, thereby realizing rapid blood oxygen measurement, and especially the initial blood oxygen response time is far superior to the prior art.
The technical problem to be solved by the invention is to avoid the defects of the technical proposal, and the technical proposal is an oxygen measuring device, comprising: the first-stage amplifying circuit comprises at least four photoelectric amplifying circuits with different amplifying times ranges, and the photoelectric amplifying circuits are respectively: the amplification factors of the four photoelectric amplifying circuits are arranged in a step shape; the circuit also comprises a secondary amplifying circuit and a bias setting module, wherein the secondary amplifying circuit is an amplifying circuit with adjustable bias; the input end of the secondary amplifying circuit is electrically connected with the output end of the primary amplifying circuit to acquire a blood oxygen measuring signal after primary amplification; the output end of the secondary amplifying circuit is electrically connected with the main control module, and outputs a blood oxygen measurement signal after secondary amplification to the main control module; one end of the bias setting module is electrically connected with the bias input end of the secondary amplifying circuit, and the other end of the bias setting module is electrically connected with the main control module; when measurement is started, the main control module sequentially acquires blood oxygen measurement signals after primary amplification by the four photoelectric amplification circuits; the main control module acquires all paths of blood oxygen measurement signals after primary amplification, and respectively carries out signal quality assessment, and one photoelectric amplification circuit with the amplitude of the blood oxygen measurement signals within a set range is selected from the four photoelectric amplification circuits to be used as a photoelectric amplification circuit for subsequent blood oxygen measurement; the main control module outputs a bias setting value to the bias setting module according to the obtained blood oxygen measuring signal after primary amplification output by the selected photoelectric amplifying circuit, and the bias setting value is used as a bias value of the secondary amplifying circuit.
In the blood oxygen measuring device, the set range of the blood oxygen measuring signal amplitude is 700-900 millivolts in the signal quality evaluation.
The main control module outputs a bias setting value to the bias setting module, wherein the bias setting value is 0.8 to 1.2 times of the blood oxygen measurement signal quantity after the primary amplification, and the blood oxygen measurement signal quantity is used as a bias value of the secondary amplification circuit.
The blood oxygen measuring device also comprises a light source driving circuit capable of adjusting the output power of the red light source or the infrared light source; when the four blood oxygen measuring signals output by the four photoelectric amplifying circuits are all smaller than 700 millivolts, the light source driving circuit adjusts the output power of the light source to be N times of the output power before, and the blood oxygen measuring signals output by the four photoelectric amplifying circuits are detected again until the blood oxygen measuring signal of at least one photoelectric amplifying circuit is larger than or equal to 700 millivolts; when the blood oxygen measuring signals output by the four photoelectric amplifying circuits are all more than 900 millivolts, the light source driving circuit adjusts the output power of the light source to be 1/N times of the previous output power, and the blood oxygen measuring signals output by the four photoelectric amplifying circuits are detected again until the blood oxygen measuring signal of at least one photoelectric amplifying circuit is less than or equal to 900 millivolts; wherein N is a natural number greater than 1.
The blood oxygen measuring device further comprises a first photoelectric amplification channel selection control circuit, wherein the first photoelectric amplification channel selection control circuit is used for selecting a photoelectric amplification channel in four photoelectric amplification circuits of the primary amplification circuit; one end of a first selection control circuit of the photoelectric amplification channel is connected with the sensor to acquire an original blood oxygen measurement signal; the other end of the first selection control circuit of the photoelectric amplification channel is electrically connected with the input end of one of the four photoelectric amplification circuits; the control end of the first selection control circuit of the photoelectric amplification channel is electrically connected with the main control module; the first selection control circuit of the photoelectric amplification channel is controlled by the main control module, and the photoelectric amplification circuit which is electrically communicated with the first selection control circuit of the photoelectric amplification channel is selected.
The technical scheme for solving the technical problems can also be an oxygen measuring system based on the oxygen measuring device, which comprises a secondary amplification channel selection control circuit; the second-stage amplifying channel selection control circuit is used for controlling the connection of the second-stage amplifying circuit and each photoelectric amplifying circuit; the input end of the second-stage amplifying channel selection control circuit is electrically connected with the output ends of the four photoelectric amplifying circuits; the output end of the second-stage amplification channel selection control circuit is electrically connected with the input end of the second-stage amplification circuit; the control end of the second-stage amplification channel selection control circuit is electrically connected with the main control module; the second-stage amplification channel selection control circuit is controlled by the main control module, and one of the four photoelectric amplification circuits is selected to be electrically communicated with the input end of the second-stage amplification circuit.
The technical scheme for solving the technical problems can also be a blood oxygen signal detection method based on the blood oxygen measuring device, which comprises the following steps: step A: sequentially connecting the first photoelectric amplifying circuit, the second photoelectric amplifying circuit, the third photoelectric amplifying circuit and the fourth photoelectric amplifying circuit to a main measuring circuit; obtaining a blood oxygen measurement signal after primary photoelectric amplification; and (B) step (B): the method comprises the steps of obtaining each path of blood oxygen measurement signals after primary photoelectric amplification by a main control module, and respectively carrying out blood oxygen measurement signal quality assessment; step C: and selecting a photoelectric amplifying circuit with the output blood oxygen measuring signal within a set range from the four photoelectric amplifying circuits to be used as a photoelectric amplifying circuit for subsequent measurement.
In the blood oxygen signal detection method, in the step C, the set range of the blood oxygen measurement signal quality assessment is 700-900 millivolts.
The blood oxygen signal detection method further comprises the step D: the main control module outputs a bias setting value to the bias setting module according to the obtained blood oxygen measuring signal after primary amplification output by the selected photoelectric amplifying circuit, and the bias setting value is used as a bias value of the secondary amplifying circuit.
In the blood oxygen signal detection method, the blood oxygen measuring device further comprises a light source driving circuit capable of adjusting the output power of the light source; in the step C, when the measurement signals output by the four photoelectric amplifying circuits are all less than 700 millivolts, the light source driving circuit adjusts the output power of the light source to be N times of the output power before, and the blood oxygen measurement signals output by the four photoelectric amplifying circuits are detected again until the blood oxygen measurement signal output by at least one photoelectric amplifying circuit is more than or equal to 700 millivolts; in the step C, when the measurement signals output by the four photoelectric amplifying circuits are all more than 900 millivolts, the light source driving circuit adjusts the output power of the light source to be 1/N times of the output power before, and the blood oxygen measurement signals output by the four photoelectric amplifying circuits are detected again until the blood oxygen measurement signal of at least one photoelectric amplifying circuit is less than or equal to 900 millivolts; wherein N is a natural number greater than 1.
Compared with the prior art, the invention has the beneficial effects that: 1. the four paths of photoelectric amplifying circuits are adopted to carry out primary screening of measurement signals, and bias setting of the secondary amplifying circuits is carried out according to the primary amplified blood oxygen measurement signals, so that the time for adapting to measurement conditions is greatly accelerated; 2. the secondary amplifying circuit with adjustable bias is arranged on the amplifying circuit, and the time for adjusting the amplifying reference voltage and the amplifying multiple of the amplifying circuit is further shortened by utilizing controllable bias, so that the adapting process between the blood oxygen measuring system and the medium to be measured is further shortened, and the method and the device can be used for rapidly matching the blood oxygen measuring conditions which are difficult to detect by conventional technical means such as thin measuring medium and the like; the mode of joint adjustment of N times of light source drive enables one-time light source adjustment to be sequentially applied to four paths of photoelectric amplifying circuits, and system adjustment time is further shortened; thereby realizing rapid blood oxygen measurement for different blood oxygen measurement, and especially the initial blood oxygen response time is far superior to the prior art.
Drawings
FIG. 1 is one of the schematic block diagrams of an embodiment of an oximetry device of the present invention;
FIG. 2 is a second schematic block diagram of an embodiment of an oximetry device according to the present invention;
FIG. 3 is a schematic block diagram of a prior art oximetry device;
FIG. 4 is a schematic flow chart of a blood oxygen measurement method;
FIG. 5 is a second schematic flow chart of the blood oxygen measurement method.
Detailed Description
Embodiments of the present invention are described in further detail below with reference to the drawings.
In one embodiment of the oximetry device and system shown in FIG. 1, the main control module is a microprocessor, and the main control module controls the optical driving circuit, the bias setting circuit, the first selection control circuit for the photoelectric amplification channel, and the second selection control circuit for the amplification channel, respectively.
As shown in fig. 1, a first selection control circuit of the photoelectric amplification channels is arranged between the sensor and the four photoelectric amplification circuits, and is used for selecting the photoelectric amplification channels in the four photoelectric amplification circuits; one end of a first selection control circuit of the photoelectric amplification channel is connected with the sensor to acquire an original blood oxygen measurement signal; the other end of the first selection control circuit of the photoelectric amplification channel is electrically connected with the input end of one of the four photoelectric amplification circuits; the control end of the first selection control circuit of the photoelectric amplification channel is electrically connected with the main control module; the first selection control circuit of the photoelectric amplification channel is controlled by the main control module, and the photoelectric amplification circuit which is electrically communicated with the first selection control circuit of the photoelectric amplification channel is selected.
In one embodiment of the oximetry device and system shown in FIG. 1, the oximetry device includes a secondary amplification circuit and a secondary amplification channel selection control circuit; the second-stage amplifying circuit is an amplifying circuit with adjustable bias; the device also comprises a bias setting module; one end of the bias setting module is electrically connected with the secondary amplifying circuit, and the other end of the bias setting module is electrically connected with the main control module; the main control module outputs a bias setting value to the bias setting module for use as a bias for the secondary amplifying circuit.
In one embodiment of the oximetry device and system shown in FIG. 1, the secondary amplification channel selection control circuit is disposed between the four-way photoelectric amplification circuit and the bias-adjustable secondary amplification circuit; the second-stage amplification channel selection control circuit is used for controlling the connection of the second-stage amplification circuit and each photoelectric amplification circuit; the input end of the second-stage amplifying channel selection control circuit is electrically connected with the output ends of the four photoelectric amplifying circuits; the output end of the second-stage amplification channel selection control circuit is electrically connected with the input end of the second-stage amplification circuit; the control end of the second-stage amplification channel selection control circuit is electrically connected with the main control module; the second-stage amplification channel selection control circuit is controlled by the main control module, and one of the four photoelectric amplification circuits is selected to be electrically communicated with the input end of the second-stage amplification circuit. In a specific embodiment of the prior art of the blood oxygen measuring device and system shown in fig. 2, only one path of analog amplifying circuit is designed, the sensor is omitted in the figure, the main control module, i.e. the microprocessor, respectively controls the light output control circuit to perform the light source adjustment and the gain adjustment of the first-stage analog amplifying circuit, and the single channel performs the dynamic range adjustment, so that the dynamic range of the single amplifying circuit is extremely high, meanwhile, the time for circuit adjustment is also increased, the quick measurement cannot be realized, the measurement requirements of different media to be measured cannot be quickly adapted, and especially in the blood oxygen measuring application of neonates or peripheral circulation disorder, the situation exceeding the dynamic range of the amplifier may occur, and the measurement failure is caused.
In the blood oxygen signal detection method shown in fig. 4, based on the blood oxygen measurement device, the method includes the following steps:
step A: sequentially connecting the first photoelectric amplifying circuit, the second photoelectric amplifying circuit, the third photoelectric amplifying circuit and the fourth photoelectric amplifying circuit to a main measuring loop; acquiring the blood oxygen measurement signals after photoelectric amplification, namely acquiring four paths of analog signals, and preprocessing the signals;
and (B) step (B): the method comprises the steps of acquiring each path of blood oxygen measurement signals after photoelectric amplification by a main control module, and respectively carrying out blood oxygen measurement signal quality assessment, namely adopting signal window threshold judgment to judge whether the acquired blood oxygen measurement signals are in a set threshold range;
step C: selecting a photoelectric amplifying circuit with the blood oxygen measuring signal within a set range from the four photoelectric amplifying circuits to be used as a photoelectric amplifying circuit for subsequent measurement; the set range of the blood oxygen measurement signal quality assessment is 700 to 900 millivolts;
in the step C, when the measurement signals output by the four photoelectric amplifying circuits are all less than or equal to 700 millivolts, the light source driving circuit adjusts the output power of the light source to be N times of the output power before, and the blood oxygen measurement signals output by the four photoelectric amplifying circuits are detected again until the blood oxygen measurement signal output by at least one photoelectric amplifying circuit is more than 700 millivolts; wherein N is a natural number greater than 1; n can be adjusted and set according to actual needs, if the obtained blood oxygen measurement signal is far less than 700 millivolts, the value of N can be large, and the output power of the light source can be quickly adjusted, for example, N is 8, 6 or 4, and the like, and the adjustment is carried out with higher times; if the obtained blood oxygen measurement signal is close to 700 millivolts, the value of N can be small, micro-adjustment of the output power of the light source can be performed, for example, N is 3 or 2, and finer adjustment of the output power of the light source can be performed;
in the step C, when the measurement signals output by the four photoelectric amplifying circuits are all more than 900 millivolts, the light source driving circuit adjusts the output power of the light source to be 1/N times of the output power before, and the blood oxygen measurement signals output by the four photoelectric amplifying circuits are detected again until the blood oxygen measurement signal of at least one photoelectric amplifying circuit is less than or equal to 900 millivolts; wherein N is a natural number greater than 1; if the obtained blood oxygen measurement signal is far more than 900 millivolts, the value of N can be taken to be large, and the output power of the light source can be quickly adjusted, for example, N is taken to be 8, 6 or 4, and the like, and the adjustment is carried out at a higher multiple; if the obtained oximetry signals are already close to 900 millivolts, the value of N may be small, and fine adjustment of the light source output power may be performed, for example, N may be 3 or 2.
In some embodiments not shown in the drawings, step D is also included: the main control module outputs a bias setting value to the bias setting module according to the obtained blood oxygen measuring signal after primary amplification output by the selected photoelectric amplifying circuit, and the bias setting value is used as a bias value of the secondary amplifying circuit.
In addition to the steps shown in fig. 4, the method for detecting an oxygen blood signal shown in fig. 5 further includes a step of selecting one of four analog signals, that is, obtaining a first-stage amplified oxygen blood measurement signal in one of four photoelectric amplifying circuits, and amplifying the signal again to obtain a second-stage signal amplification.
When the secondary signal is amplified, the secondary signal amplifying circuit can be biased by utilizing the blood oxygen measurement signal quantity output by the primary amplifying circuit; the basis for bias setting of the secondary signal amplifying circuit is that the bias amplitude and the amplification factor of the secondary amplified signal are obtained after signal acquisition and signal preprocessing and are used for determining the bias setting and the target value of adjustment; and after the signal preprocessing, carrying out signal characteristic recognition and calculation, and outputting waveforms and calculation parameters. The main control module outputs a bias setting value to the bias setting module, which is 0.8 to 1.2 times the magnitude of the blood oxygen measurement signal after the primary amplification, and is used as the bias value of the secondary amplification circuit. In one embodiment, the bias value of the secondary signal amplification circuit may be set to the oximetry semaphore; of course, a value of 0.8 to 1.2 times the magnitude of the oximetry signal may also be selected as the offset value. The bias may be a voltage type bias or a current type bias, and the bias may be converted into a corresponding voltage bias when the current type bias is applied. The bias setting mode greatly improves the working efficiency and the adjusting time of the secondary amplifying circuit, and the amplifying capability of the secondary amplifying circuit is fastest applied to the amplifying of differential signals.
The multiple first-stage photoelectric amplifying circuits are used for collecting real-time signals output by the first-stage photoelectric amplifying circuits and collecting one-stage amplified blood oxygen measuring signals, and the multiple first-stage photoelectric amplifying circuits are used for selecting multiple first-stage photoelectric amplifying circuits and the bias setting of the adjustable gain for the second-stage amplification. A large circulation for adjusting the system and adapting to the external measurement conditions is formed between the light source driving circuit and the primary amplifying circuit, and the primary amplifying circuit is adjusted to be in a state of being most suitable for the external measurement conditions through cooperative adjustment between the primary circuit and the light source driving circuit; on the basis, small-cycle cooperative adjustment of the primary amplifying circuit and the secondary amplifying circuit is performed, so that locking of a measurement target condition is realized quickly, quick acquisition of pulse signals and quick calculation of blood oxygen are realized, and a joint adjustment process of the two-stage amplifying circuit belongs to the prior art and is not repeated here.
Compared with other technologies, the blood oxygen measuring device, the blood oxygen measuring system and the blood oxygen signal detection method designed by the invention adopt four paths of photoelectric amplifying circuits to carry out primary screening of measuring signals, thereby greatly accelerating the time for adapting to measuring conditions; the mode of N times of light source driving joint adjustment ensures that the primary light source adjustment can be sequentially applied to four paths of photoelectric amplifying circuits, thereby further accelerating the system adjustment time; the secondary amplifying circuit with adjustable bias is arranged on the amplifying circuit, and the time for adjusting the amplifying reference voltage and the amplifying multiple of the amplifying circuit is further shortened by utilizing controllable bias, so that the adapting process between the blood oxygen measuring system and the medium to be measured is further shortened, and the method and the device can be used for rapidly matching the blood oxygen measuring conditions which are difficult to detect by conventional technical means such as thin measuring medium and the like; thereby realizing rapid blood oxygen measurement for different blood oxygen measurement, and especially the initial blood oxygen response time is far superior to the prior art.
The blood oxygen signal detection mode based on the combined adjustment mechanism of multipath analog signal acquisition and bidirectional light source driving can be rapidly matched with different media to be measured for adjustment, the blood oxygen signal detection method can be applied to different blood oxygen measurement systems and devices, and the adaptability of the blood oxygen signal detection method in different measurement positions such as finger thickness, earlobe and the like and the rapid response of the whole measurement system can be expanded through improvement and optimization of the method.
The method has excellent clinical application value, is one of the requisite blood oxygen monitoring technologies for operation, intensive care and emergency treatment, can completely replace imported similar measurement technologies in terms of measurement function and key indexes, especially in terms of the response capability of rapidly responding to output blood oxygen values, and can generate remarkable economic benefit.
The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent structures or equivalent processes using the contents of the specification and drawings, or direct or indirect application in other related technical fields, are included in the scope of the invention.
Claims (10)
1. An oximetry device comprising:
the first-stage amplifying circuit comprises at least four photoelectric amplifying circuits with different amplifying times ranges, and the photoelectric amplifying circuits are respectively: the amplification factors of the four photoelectric amplifying circuits are arranged in a step shape; the circuit also comprises a secondary amplifying circuit and a bias setting module, wherein the secondary amplifying circuit is an amplifying circuit with adjustable bias; the input end of the secondary amplifying circuit is electrically connected with the output end of the primary amplifying circuit to acquire a blood oxygen measuring signal after primary amplification; second-level
The output end of the amplifying circuit is electrically connected with the main control module, and outputs a blood oxygen measurement signal after secondary amplification to the main control module; one end of the bias setting module is electrically connected with the bias input end of the secondary amplifying circuit, and the other end of the bias setting module is electrically connected with the main control module; when measurement is started, the main control module sequentially acquires blood oxygen measurement signals after primary amplification by the four photoelectric amplification circuits;
the main control module acquires all paths of blood oxygen measurement signals after primary amplification, and respectively carries out signal quality assessment, and one photoelectric amplification circuit with the amplitude of the blood oxygen measurement signals within a set range is selected from the four photoelectric amplification circuits to be used as a photoelectric amplification circuit for subsequent blood oxygen measurement;
the main control module outputs a bias setting value to the bias setting module according to the obtained blood oxygen measuring signal after primary amplification output by the selected photoelectric amplifying circuit, and the bias setting value is used as a bias value of the secondary amplifying circuit.
2. The oximetry device according to claim 1, wherein:
in the signal quality assessment, the set range of the blood oxygen measurement signal amplitude is 700 to 900 millivolts.
3. The oximetry device according to claim 1, wherein:
the main control module outputs a bias setting value to the bias setting module, wherein the bias setting value is 0.8 to 1.2 times of the blood oxygen measurement signal quantity after the primary amplification, and the blood oxygen measurement signal quantity is used as a bias value of the secondary amplification circuit.
4. The oximetry device according to claim 1, wherein:
the light source driving circuit is used for adjusting the output power of the red light source or the infrared light source;
when the four blood oxygen measuring signals output by the four photoelectric amplifying circuits are all smaller than 700 millivolts, the light source driving circuit adjusts the output power of the light source to be N times of the output power before, and the blood oxygen measuring signals output by the four photoelectric amplifying circuits are detected again until the blood oxygen measuring signal of at least one photoelectric amplifying circuit is larger than or equal to 700 millivolts; when the blood oxygen measurement signals output by the four photoelectric amplifying circuits are all more than 900 millivolts, the light source driving circuit adjusts the output power of the light source to be 1/N times of the previous output power, and the four photoelectric amplifying circuits are detected again
The blood oxygen measuring signal output by the circuit is up to 900 millivolts or less; wherein N is a natural number greater than 1.
5. The oximetry device according to claim 1, wherein:
the photoelectric amplification channel first selection control circuit is used for selecting the photoelectric amplification channel in the four photoelectric amplification circuits of the primary amplification circuit;
one end of a first selection control circuit of the photoelectric amplification channel is connected with the sensor to acquire an original blood oxygen measurement signal;
the other end of the first selection control circuit of the photoelectric amplification channel is electrically connected with the input end of one of the four photoelectric amplification circuits; the control end of the first selection control circuit of the photoelectric amplification channel is electrically connected with the main control module; the first selection control circuit of the photoelectric amplification channel is controlled by the main control module, and the photoelectric amplification circuit which is electrically communicated with the first selection control circuit of the photoelectric amplification channel is selected.
6. An oximetry system based on the oximetry device according to any one of claims 1 to 5, characterized in that:
comprises a secondary amplification channel selection control circuit; the second-stage amplifying channel selection control circuit is used for controlling the connection of the second-stage amplifying circuit and each photoelectric amplifying circuit; the input end of the second-stage amplifying channel selection control circuit is electrically connected with the output ends of the four photoelectric amplifying circuits; the output end of the second-stage amplification channel selection control circuit is electrically connected with the input end of the second-stage amplification circuit; the control end of the second-stage amplification channel selection control circuit is electrically connected with the main control module; the second-stage amplification channel selection control circuit is controlled by the main control module, and one of the four photoelectric amplification circuits is selected to be electrically communicated with the input end of the second-stage amplification circuit.
7. A blood oxygen signal detection method based on the blood oxygen measurement device according to any one of claims 1 to 5, comprising the steps of:
step A: sequentially connecting the first photoelectric amplifying circuit, the second photoelectric amplifying circuit, the third photoelectric amplifying circuit and the fourth photoelectric amplifying circuit to a main measuring circuit; obtaining a blood oxygen measurement signal after primary photoelectric amplification;
and (B) step (B): the method comprises the steps of obtaining each path of blood oxygen measurement signals after primary photoelectric amplification by a main control module, and respectively carrying out blood oxygen measurement signal quality assessment;
step C: and selecting a photoelectric amplifying circuit with the output blood oxygen measuring signal within a set range from the four photoelectric amplifying circuits to be used as a photoelectric amplifying circuit for subsequent measurement.
8. The blood oxygen signal detection method according to claim 7, wherein:
in step C, the set range for the blood oxygen measurement signal quality assessment is between 700 and 900 millivolts.
9. The blood oxygen signal detection method according to claim 7, further comprising,
step D: the main control module outputs a bias setting value to the bias setting module according to the obtained blood oxygen measuring signal after primary amplification output by the selected photoelectric amplifying circuit, and the bias setting value is used as a bias value of the secondary amplifying circuit.
10. The blood oxygen signal detection method according to claim 7, wherein:
the blood oxygen measuring device also comprises a light source driving circuit capable of adjusting the output power of the light source;
in the step C, when the measurement signals output by the four photoelectric amplifying circuits are all less than 700 millivolts, the light source driving circuit adjusts the output power of the light source to be N times of the output power before, and the blood oxygen measurement signals output by the four photoelectric amplifying circuits are detected again until the blood oxygen measurement signal output by at least one photoelectric amplifying circuit is more than or equal to 700 millivolts; in the step C, when the measurement signals output by the four photoelectric amplifying circuits are all more than 900 millivolts, the light source driving circuit adjusts the output power of the light source to be 1/N times of the output power before, and the blood oxygen measurement signals output by the four photoelectric amplifying circuits are detected again until the blood oxygen measurement signal of at least one photoelectric amplifying circuit is less than or equal to 900 millivolts; wherein N is a natural number greater than 1.
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