CN116831558B - Breath impedance calculation method and calculation device based on forced oscillation - Google Patents
Breath impedance calculation method and calculation device based on forced oscillation Download PDFInfo
- Publication number
- CN116831558B CN116831558B CN202310789822.1A CN202310789822A CN116831558B CN 116831558 B CN116831558 B CN 116831558B CN 202310789822 A CN202310789822 A CN 202310789822A CN 116831558 B CN116831558 B CN 116831558B
- Authority
- CN
- China
- Prior art keywords
- oscillation
- impedance
- signal
- pressure
- flow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000010355 oscillation Effects 0.000 title claims abstract description 117
- 238000004364 calculation method Methods 0.000 title claims abstract description 84
- 230000000241 respiratory effect Effects 0.000 claims abstract description 100
- 238000012360 testing method Methods 0.000 claims abstract description 40
- 238000000926 separation method Methods 0.000 claims abstract description 17
- 238000003491 array Methods 0.000 claims abstract description 16
- 238000006243 chemical reaction Methods 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 230000029058 respiratory gaseous exchange Effects 0.000 claims description 15
- 230000036760 body temperature Effects 0.000 claims description 10
- 230000002093 peripheral effect Effects 0.000 claims description 9
- 230000007613 environmental effect Effects 0.000 claims description 8
- 238000012937 correction Methods 0.000 claims description 7
- 238000004590 computer program Methods 0.000 claims 4
- 101100202428 Neopyropia yezoensis atps gene Proteins 0.000 claims 2
- 238000000034 method Methods 0.000 abstract description 15
- 210000004072 lung Anatomy 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000000691 measurement method Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- 238000003556 assay Methods 0.000 description 1
- 208000006673 asthma Diseases 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 210000000621 bronchi Anatomy 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 210000000038 chest Anatomy 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000004064 dysfunction Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000001727 in vivo Methods 0.000 description 1
- 230000004199 lung function Effects 0.000 description 1
- 230000000414 obstructive effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000036581 peripheral resistance Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000002685 pulmonary effect Effects 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 210000002345 respiratory system Anatomy 0.000 description 1
- 102220065682 rs77311724 Human genes 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/08—Detecting, measuring or recording devices for evaluating the respiratory organs
- A61B5/085—Measuring impedance of respiratory organs or lung elasticity
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
- A61B5/7253—Details of waveform analysis characterised by using transforms
- A61B5/7257—Details of waveform analysis characterised by using transforms using Fourier transforms
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Medical Informatics (AREA)
- Animal Behavior & Ethology (AREA)
- Pathology (AREA)
- Physiology (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Veterinary Medicine (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Biophysics (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Pulmonology (AREA)
- Artificial Intelligence (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Psychiatry (AREA)
- Signal Processing (AREA)
- Mathematical Physics (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
The invention relates to a breath impedance calculating method and a calculating device based on forced oscillation, wherein the calculating method comprises the following steps: s1, acquiring a tested mixed pressure signal and a mixed flow signal; s2, generating a preset number of separation arrays according to the mixed pressure signals and the mixed flow signals, and performing FFT (fast Fourier transform) calculation on the separation arrays; s3, acquiring Amplitude value Amplitude and Phase corresponding to a preset oscillation signal frequency range based on an array after FFT fast Fourier transform calculation, and respectively calculating a complex real part and a complex imaginary part of an oscillation Pressure signal Pressure and an oscillation Flow signal Flow; s4, calculating and generating complex numbers of respiratory impedance corresponding to each frequency. Through the technical scheme, the problem that an original signal of the current respiratory impedance test is disordered and an oscillation signal cannot be extracted to obtain respiratory impedance can be solved.
Description
Technical Field
The invention relates to the technical field of respiratory impedance testing, in particular to a respiratory impedance calculating method and a calculating device based on forced oscillation.
Background
Vital activities require oxygen, which is required to be obtained by respiration. The external fresh air needs to pass through the air pipe which is continuously branched and narrowed and thinned to reach the alveolar part of the air exchange, and the process needs to consume energy and has respiratory resistance.
The most common clinically is obstructive ventilation dysfunction, increased airway resistance, such as asthma, slow lung obstruction, etc. The conventional lung ventilation function test is to indirectly reflect the smoothness of the airway by using a Flow (Flow) index, and the Flow parameter is obtained by a Flow sensor.
In fact the flow is pressure dependent; the coordination degree of the test subject is good, the forced expiration action is good, the pressure is high, and the flow index is high, so the test is influenced by subjective factors. If the flow rate can be tested and the pressure (namely the respiratory resistance) can be tested, the clinical examination is not influenced by the fit degree of the patient, and the unobstructed degree of the respiratory tract can be reflected directly most ideally.
As shown in fig. 1, the principle of measurement of respiratory resistance is similar to that of resistance measurement of a circuit. Where respiratory resistance = respiratory pressure difference/respiratory flow.
The measured respiratory resistance is divided into physical properties: the viscous, elastic and inertial resistances of the airways are known as respiratory resistance (Zrs).
As shown in fig. 2, the three different properties of respiratory resistance are distributed in the body as follows:
the triangle part (center Resistance Rz, peripheral Resistance Rp) is the viscous Resistance (Resistance) of the airway, distributed in the large and small airways and lung tissues, but most comes from the airways, namely the clinically referred airway Resistance;
the pulmonary profile (Ers) is the elastic resistance of respiration (Capacitance), which is primarily distributed in the lungs, lung tissue, alveoli and the extendible fine bronchi, described clinically by conventional Compliance (Compliance, reciprocal of elastic resistance);
the rim portion (Lz) is the inertial resistance of the airway (insertance), which is mainly present in the large airway and the thorax.
Currently, the respiratory impedance testing apparatus in the prior art is basically a product of yeger in germany (currently purchased by Vyaire corporation in usa), almost monopolizing the global forced oscillation market, and the general principle of the product is as follows:
the loudspeaker is used as a signal source to generate pulse signals; the pressure difference type flow sensor is adopted, the internal structure of the pressure difference type flow sensor is a resistance net, pressure attenuation is generated when gas flows through the resistance net, and the larger the gas flow is, the larger the pressure difference is; the flow rate of the gas can be obtained by the pressure difference while also measuring the oscillation pressure. For the signal source, the reference impedance and the respiratory impedance of the human body are connected in parallel, the total impedance is obtained first, and since the reference impedance is known, the respiratory impedance of the human body can be deduced.
In practice, according to a measurement method of respiratory resistance (i.e. pressure divided by flow), a conventional test method generally makes a subject breathe in cooperation with the respiration to perform a corresponding respiration action, thereby obtaining pressure and flow signals generated by the subject; that is to say the signal source is built-in, i.e. the patient himself, which is completely influenced by the patient's fit.
As shown in fig. 3, the principle of the forced oscillation measurement method is as follows:
the forced oscillation method externally places a signal source, is externally generated and is applied to a human body; that is, the pressure signal is generated by an external machine, and the flow signal is a passive flow change generated by the human body on the external pressure signal, and is not the original breathing flow of the patient.
Such a measurement method is not affected by the patient's compliance; since the excitation signal is generated by an external machine, the device is stable, reliable and has good repeatability. But the greatest difficulty is how to extract the signal from the respiratory wave.
In other words, in the respiratory impedance testing device, the original signals such as flow and pressure obtained from the testing head are very disordered, and the original signals are mixed with the external oscillation signals and the respiratory signals of the human body, so that any rule cannot be seen at all in the time domain; thus, the oscillation signal cannot be extracted from the human respiratory wave, and the respiratory impedance cannot be obtained.
Disclosure of Invention
In order to solve the technical problems, the invention provides a breath impedance calculating method and a breath impedance calculating device based on forced oscillation, wherein the calculating method is used for solving the problems that an original signal of a current breath impedance test is disordered and an oscillation signal cannot be extracted to obtain the breath impedance.
To achieve the above object, the present invention provides a breath impedance calculating method based on forced oscillation, including:
s1, after a breath impedance testing device based on forced oscillation starts an oscillation test, acquiring a tested mixed pressure signal and a mixed flow signal;
s2, generating a preset number of separation arrays according to the mixed pressure signals and the mixed flow signals, and carrying out FFT (fast Fourier transform) calculation on the separation arrays;
s3, acquiring Amplitude value Amplitude and Phase value Phase corresponding to a preset oscillation signal frequency range based on an array after FFT fast Fourier transform calculation, and respectively calculating a complex real part and a complex imaginary part of an oscillation Pressure signal Pressure and an oscillation Flow signal Flow according to the Amplitude value Amplitude and the Phase value Phase;
and S4, calculating and generating a complex number of respiratory impedance corresponding to each frequency according to the oscillation Pressure signal Pressure and the complex real part and the complex imaginary part of the oscillation Flow signal Flow.
Further, S2 specifically includes:
s21, acquiring environmental parameters for BTPS body temperature and environmental pressure correction recorded by the respiratory impedance testing device;
s22, after the respiratory impedance testing device completes oscillation testing, converting the mixed flow signal from ATPS ambient temperature and ambient pressure to BTPS body temperature and ambient pressure; the conversion calculation formula is as follows:
flow btps=flow ATPS BTPS conversion coefficient;
wherein BTPS conversion coefficient= (atmospheric pressure PB-ambient temperature Water vapor partial pressure Prt Water)/(atmospheric pressure PB-body temperature Water vapor partial pressure Pbt Water) ×273+37 ℃ body temperature bt)/(273+ambient temperature rt);
s23, FFT fast Fourier transform calculation is carried out on the separated array.
Further, S3 specifically includes:
s31, acquiring the Amplitude value Amplitude and the Phase value Phase corresponding to the frequency range of the oscillation signal of 5 Hz-30 Hz;
s32, respectively calculating a complex real part and a complex imaginary part of the oscillation Pressure signal Pressure and the oscillation Flow signal Flow according to a first complex calculation formula and the Amplitude and the Phase value Phase; wherein, the first complex calculation formula is:
Pressure(f)＝PressAmplitude(f)*Cos(PressPhase*PI()/180)+jPressAmplitude(f)*Sin(PressPhase*PI()/180)＝a+jb；
Flow(f)＝FlowAmplitude(f)Cos(FlowPhase*PI()/180)+jFlowAmplitude(f)*Sin(FlowPhase*PI()/180)＝c+jd。
further, S4 specifically includes:
calculating the complex number of the respiratory impedance according to a second complex number calculation formula; wherein the second complex calculation formula is:
zrs (f) =pressure (f)/Flow (f) =real impedance+imaginary impedance;
wherein Zrs (f) is respiratory impedance, real part of impedance= (a×c+b×d)/(c×2+d×2); impedance imaginary = (b c-a d)/(c 2+ d 2).
Further, the computing method further includes:
s5, calculating the total respiratory impedance corresponding to the frequency of the 5Hz oscillating signal according to a total respiratory impedance calculation formula; wherein, the total respiratory impedance calculation formula is:
zrs-5 hz=sqrt (real part of impedance ≡2+ imaginary part of impedance ≡2);
s6, calculating a phase angle corresponding to the frequency of the 5Hz oscillating signal according to a phase angle calculation formula; wherein, the phase angle calculation formula is:
phase angle dPhase = phase pressure phase of pressure-phase flow of flow;
s7, respectively obtaining total viscous air passage resistance R5, central air passage resistance R20 and peripheral elastic resistance X5; the total resistance R5 of the viscous air passage is equal to the real part of respiratory impedance corresponding to the 5Hz oscillating signal frequency, the resistance R20 of the central air passage is equal to the real part of respiratory impedance corresponding to the 20Hz oscillating signal frequency, and the peripheral elastic resistance X5 is equal to the imaginary part of respiratory impedance corresponding to the 5Hz oscillating signal frequency.
Further, the computing method further includes:
s8, acquiring a resonance frequency Fres according to the X-ray of the imaginary part of the respiratory impedance; wherein the corresponding frequency of the intersection point of the respiratory impedance imaginary part X line and the zero-point line is the resonance frequency Fres.
Further, the computing method further includes:
s9, calculating reactance area AX according to the respiratory impedance imaginary part X line; the reactance area AX is equal to the area formed by surrounding the respiratory impedance imaginary part X line below the zero line.
The invention also provides a breath impedance calculating device based on forced oscillation, which is used for realizing the breath impedance calculating method based on forced oscillation, and comprises the following steps:
a mixed signal acquisition unit configured to: after the breath impedance testing device based on forced oscillation starts an oscillation test, a tested mixed pressure signal and a mixed flow signal are obtained;
a conversion calculation unit configured to: generating a preset number of separation arrays according to the mixed pressure signals and the mixed flow signals, and performing FFT (fast Fourier transform) calculation on the separation arrays;
an oscillation signal complex calculation unit for: acquiring Amplitude and Phase value Phase corresponding to a preset oscillation signal frequency range based on an array after FFT fast Fourier transform calculation, and respectively calculating a complex real part and a complex imaginary part of an oscillation Pressure signal Pressure and an oscillation Flow signal Flow according to the Amplitude and the Phase value Phase;
a respiratory impedance complex calculation unit for: and calculating and generating a complex number of respiratory impedance corresponding to each frequency according to the oscillation Pressure signal Pressure and the complex real part and the complex imaginary part of the oscillation Flow signal Flow.
Compared with the prior art, the technical scheme provided by the invention has the following technical effects:
in the invention, in order to extract an oscillation signal from an original signal of a respiratory impedance test, a tested mixed signal comprising a mixed pressure signal and a mixed flow signal is firstly obtained;
then, generating a preset number of separation arrays, and performing FFT (fast Fourier transform) calculation to obtain a converted and calculated array;
acquiring amplitude and phase values corresponding to the frequency of the oscillation signal of the detection equipment from the array after conversion calculation, thereby calculating the complex number of the oscillation pressure signal and the complex number of the oscillation flow signal;
then, calculating the complex respiratory impedance corresponding to each frequency based on the two complex numbers;
therefore, the quick FFT conversion (namely, the quick Fourier transform) tool is utilized to convert the disordered original signal of the respiratory impedance test from the time domain signal to the frequency domain, so as to extract the oscillation signal from the respiratory wave of the human body, and then the respiratory impedance is obtained according to the corresponding algorithm.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of the principle of measurement of respiratory resistance in the prior art;
FIG. 2 is a schematic illustration of the prior art in vivo distribution of respiratory resistance;
FIG. 3 is a schematic diagram of a forced oscillation assay;
FIG. 4 is a flow chart of a breath impedance calculation method based on forced oscillation according to the first embodiment of the invention;
FIG. 5 is a schematic diagram of a water vapor partial pressure data table in accordance with an embodiment of the present invention;
fig. 6 is a schematic diagram of the imaginary X-ray and zero-point line of the respiratory impedance in the practical embodiment of the invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Embodiment one:
as shown in fig. 4, an embodiment of the present invention provides a breath impedance calculating method based on forced oscillation, including:
s1, after a breath impedance testing device based on forced oscillation starts an oscillation test, acquiring a tested mixed pressure signal and a mixed flow signal;
s2, generating a preset number of separation arrays according to the mixed pressure signals and the mixed flow signals, and performing FFT (fast Fourier transform) calculation on the separation arrays;
s3, acquiring Amplitude value Amplitude and Phase value Phase corresponding to a preset oscillation signal frequency range based on an array obtained after FFT fast Fourier transform calculation, and respectively calculating a complex real part and a complex imaginary part of an oscillation Pressure signal Pressure and an oscillation Flow signal Flow according to the Amplitude value Amplitude and the Phase value Phase;
s4, calculating and generating complex numbers of breathing impedance corresponding to each frequency according to the complex real parts and the complex imaginary parts of the oscillation Pressure signal Pressure and the oscillation Flow signal Flow.
In a specific embodiment, in order to extract an oscillation signal from an original signal of a respiratory impedance test, a tested mixed signal including a mixed pressure signal and a mixed flow signal is firstly obtained;
then, generating a preset number of separation arrays, and performing FFT (fast Fourier transform) calculation to obtain a converted and calculated array;
acquiring amplitude and phase values corresponding to the frequency of the oscillation signal of the detection equipment from the array after conversion calculation, thereby calculating the complex number of the oscillation pressure signal and the complex number of the oscillation flow signal;
then, calculating the complex respiratory impedance corresponding to each frequency based on the two complex numbers;
therefore, the quick FFT conversion (namely, the quick Fourier transform) tool is utilized to convert the disordered original signal of the respiratory impedance test from the time domain signal to the frequency domain, so as to extract the oscillation signal from the respiratory wave of the human body, and then the respiratory impedance is obtained according to the corresponding algorithm.
In practice, the development of the oscillation signal technology is rapid, the early forced vibration adopts an oscillation signal with a single frequency (such as 5 Hz), and other frequencies are found to be significant later, so that a plurality of frequencies are increased and multi-frequency oscillation is realized; then, the pseudo-random signal is better used as an oscillation signal source, and the pseudo-random signal is used as a forced oscillation signal source, which is called random oscillation; in the last 15 years, a pulse signal source is better, and a pulse signal is adopted as a forced oscillation signal source, which is called pulse oscillation. Starting from different oscillation signal sources has the advantage that many machines now use only one excitation signal.
The breath impedance calculation method based on forced oscillation provided by the embodiment of the invention is suitable for various different test methods such as single frequency, multi-frequency, pulse oscillation and the like.
The original signals such as flow and pressure obtained by the test equipment from the test head are very messy, and the original signals are mixed with the external oscillation signals and the breathing signals of the human body, so that any rule cannot be seen in the time domain.
Specifically, after the test signal reaches the upper computer PC, since the pressure and flow signals mix the oscillation signal and the normal respiratory wave signal, an FFT (i.e., fast fourier transform) must be introduced to convert the time domain signal to the frequency domain for analysis.
Because the respiratory wave frequency is relatively low, about 0.25-0.35Hz, and the oscillating signal frequency is about 5H-35 Hz, the respiratory wave of the human body can be removed very clearly after conversion, and thus, useful oscillating signals are extracted for subsequent analysis.
Namely, the method converts the time domain signal into the frequency domain by using a fast FFT (fast Fourier transform) tool, thereby realizing the extraction of the oscillation signal from the human respiratory wave, and then obtaining the respiratory impedance according to the corresponding algorithm.
In a preferred embodiment, S2 specifically includes:
s21, acquiring environmental parameters for BTPS body temperature and environmental pressure correction recorded by a respiratory impedance testing device;
s22, after the respiratory impedance testing device completes oscillation testing, converting the mixed flow signal from the ambient temperature and the ambient pressure of the ATPS to the ambient temperature and the ambient pressure of the BTPS body; the conversion calculation formula is as follows:
flow btps=flow ATPS BTPS conversion coefficient;
wherein BTPS conversion coefficient= (atmospheric pressure PB-ambient temperature Water vapor partial pressure Prt Water)/(atmospheric pressure PB-body temperature Water vapor partial pressure Pbt Water) ×273+37 ℃ body temperature bt)/(273+ambient temperature rt);
s23, FFT fast Fourier transform calculation is carried out on the separation array.
Thus, the BTPS correction can be performed on the flow signal by a specific algorithm, so that all time domain signals can be converted into frequency domain signals by FFT conversion calculation, and the real part and the imaginary part of the respiratory impedance ZRS can be calculated.
In a preferred embodiment, S3 specifically includes:
s31, amplitude value Amplitude and Phase corresponding to the frequency range of the oscillation signal of 5 Hz-30 Hz are obtained;
s32, respectively calculating a complex real part and a complex imaginary part of an oscillation Pressure signal Pressure and an oscillation Flow signal Flow according to a first complex calculation formula and according to the Amplitude and the Phase value Phase; the first complex calculation formula is as follows:
Pressure(f)＝PressAmplitude(f)*Cos(PressPhase*PI()/180)+jPressAmplitude(f)*Sin(PressPhase*PI()/180)＝a+jb；
Flow(f)＝FlowAmplitude(f)Cos(FlowPhase*PI()/180)+jFlowAmplitude(f)*Sin(FlowPhase*PI()/180)＝c+jd。
in a preferred embodiment, S4 specifically includes:
calculating a complex number of the respiratory impedance according to a second complex number calculation formula; wherein, the second complex calculation formula is:
zrs (f) =pressure (f)/Flow (f) =real impedance+imaginary impedance;
wherein Zrs (f) is respiratory impedance, real part of impedance= (a×c+b×d)/(c×2+d×2); impedance imaginary = (b c-a d)/(c 2+ d 2).
In a preferred embodiment, the computing method further comprises:
s5, calculating the total respiratory impedance corresponding to the frequency of the 5Hz oscillating signal according to a total respiratory impedance calculation formula; the calculation formula of the total respiratory impedance is as follows:
zrs-5 hz=sqrt (real part of impedance ≡2+ imaginary part of impedance ≡2);
s6, calculating a phase angle corresponding to the frequency of the 5Hz oscillating signal according to a phase angle calculation formula; wherein, the phase angle calculation formula is:
phase angle dPhase = phase pressure phase of pressure-phase flow of flow;
s7, respectively obtaining total viscous air passage resistance R5, central air passage resistance R20 and peripheral elastic resistance X5; the total resistance R5 of the viscous air passage is equal to the real part of respiratory impedance corresponding to the 5Hz oscillating signal frequency, the resistance R20 of the central air passage is equal to the real part of respiratory impedance corresponding to the 20Hz oscillating signal frequency, and the peripheral elastic resistance X5 is equal to the imaginary part of respiratory impedance corresponding to the 5Hz oscillating signal frequency.
Thus, the viscous air passage total resistance R5, the central air passage resistance R20 and the peripheral elastic resistance X5 are calculated by a specific algorithm.
In a preferred embodiment, the computing method further comprises:
s8, acquiring a resonance frequency Fres according to the X-ray of the imaginary part of the respiratory impedance; wherein, the corresponding frequency of the intersection point of the respiratory impedance imaginary part X line and the zero point line is the resonance frequency Fres.
In a preferred embodiment, the computing method further comprises:
s9, calculating reactance area AX according to the respiratory impedance imaginary part X line; the reactance area AX is equal to the area formed by enclosing the imaginary part X line of the respiratory impedance below the zero line.
Thus, the reactance area AX and the resonance frequency Fres can be obtained by breathing the imaginary X-ray of the impedance.
In an actual embodiment, the respiratory impedance testing device is an intelligent voice-guided linkage lung function automatic control command system;
the specific test process of the breath impedance calculation method based on forced oscillation and the impedance calculation method are as follows:
step 1: the equipment is verified after capacity calibration, and environmental parameters are recorded for BTPS (namely body temperature, environmental pressure) correction;
wherein BTPS correction refers to data to correct the gas at ambient conditions to 37 degrees, 100% relative humidity and standard atmospheric pressure;
step 2: the patient is provided with a test mouth and a nose clip, presses the cheek and calms the breath;
step 3: after starting oscillation, collecting and recording pressure and flow waveforms (through an Online interface), wherein the pressure and flow waveforms are generally 30-45 seconds;
step 4: after stopping, firstly converting the Flow signal from ATPS (namely ambient temperature and ambient pressure) to BTPS; then separating the data of pressure and flow into an array of 2 n, and delivering the array to an FFT conversion program for calculation;
the specific calculation method is as follows:
flow btps=flow ATPS BTPS conversion coefficient;
wherein BTPS conversion coefficient= (atmospheric pressure PB-ambient temperature Water vapor partial pressure Prt Water)/(atmospheric pressure PB-body temperature Water vapor partial pressure Pbt Water) ×273+37 ℃ body temperature bt)/(273+ambient temperature rt);
the water vapor partial pressure can be obtained by looking up a table according to the table data in the figure, as shown in fig. 5.
Step 5: the Amplitude and the Phase in 5 Hz-30 Hz are found in the array after FFT, and the complex real part and the imaginary part of the Pressure and the Flow are calculated according to the following formulas:
Pressure(f)＝PressAmplitude(f)*Cos(PressPhase*PI()/180)+jPressAmplitude(f)*Sin(PressPhase*PI()/180)＝a+jb；
Flow(f)＝FlowAmplitude(f)Cos(FlowPhase*PI()/180)+jFlowAmplitude(f)*Sin(FlowPhase*PI()/180)＝c+jd；
step 6: respiratory impedance at each frequency was calculated:
zrs (f) =pressure (f)/Flow (f) =real impedance+imaginary impedance;
wherein, the real part of the impedance= (a c+b d)/(c 2+d 2), the imaginary part of the impedance= (b c-a d)/(c 2+d 2);
step 7: calculate the total respiratory impedance at 5 Hz:
zrs-5 Hz=SQRT (real part of impedance ζ2+imaginary part of impedance ζ2)
Step 8: calculate the phase angle at 5 Hz:
phase angle dPhase = phase pressure phase of pressure-phase flow of flow;
step 9: respectively obtaining a breathing impedance real part when the total resistance of the viscous airway is R5=5 Hz, a breathing impedance real part when the central airway resistance is R20=20 Hz and a breathing impedance imaginary part when the peripheral elastic resistance is X5=5 Hz;
step 10: defining and calculating a resonance frequency Fres;
as shown in fig. 6, the point of zero crossing of the imaginary X-ray of the respiratory impedance is the resonance frequency Fres;
the position of the X-ray solid line crossing the dot-like zero-point dashed line in the figure is about 10 Hz;
step 11: calculating a reactance area AX, namely an area formed by all X rays below a zero point is AX; as shown in fig. 6, the reactance area AX is a gray part area.
Thus, the breathing impedance calculating method based on forced oscillation has the following advantages:
1) BTPS correction can be performed on the flow signal, and an algorithm is included;
2) All time domain signals can be converted into frequency domain signals (through FFT conversion);
3) The real and imaginary parts of the respiratory impedance ZRS can be calculated;
4) The total resistance R5 of the viscous air passage, the central air passage resistance R20 and the peripheral elastic resistance X5 can be calculated;
5) The reactance area AX and the resonance frequency Fres can be calculated.
It should be noted that, although the steps in the flowchart are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least a portion of the steps in the flowcharts may include a plurality of sub-steps or stages that are not necessarily performed at the same time, but may be performed at different times, the order in which the sub-steps or stages are performed is not necessarily sequential, and may be performed in turn or alternately with at least a portion of the sub-steps or stages of other steps or other steps.
Embodiment two:
the embodiment of the invention also provides a breath impedance calculating device based on forced oscillation, which is used for realizing the breath impedance calculating method based on forced oscillation, and comprises the following steps:
a mixed signal acquisition unit configured to: after the breath impedance testing device based on forced oscillation starts an oscillation test, a tested mixed pressure signal and a mixed flow signal are obtained;
a conversion calculation unit configured to: generating a preset number of separation arrays according to the mixed pressure signals and the mixed flow signals, and performing FFT (fast Fourier transform) calculation on the separation arrays;
an oscillation signal complex calculation unit for: acquiring Amplitude and Phase value Phase corresponding to a preset oscillation signal frequency range based on an array calculated by FFT (fast Fourier transform), and respectively calculating complex real parts and complex imaginary parts of an oscillation Pressure signal Pressure and an oscillation Flow signal Flow according to the Amplitude and the Phase value Phase;
a respiratory impedance complex calculation unit for: and calculating and generating a complex number of breathing impedance corresponding to each frequency according to the complex real part and the complex imaginary part of the oscillation Pressure signal Pressure and the oscillation Flow signal Flow.
For specific limitations of the above apparatus, reference may be made to the limitations of the method described above, which are not repeated here.
It should be noted that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (8)
1. A breath impedance calculation method based on forced oscillation, comprising:
s1, after a breath impedance testing device based on forced oscillation starts an oscillation test, acquiring a tested mixed pressure signal and a mixed flow signal;
s2, generating a preset number of separation arrays according to the mixed pressure signals and the mixed flow signals, and carrying out FFT (fast Fourier transform) calculation on the separation arrays;
s3, acquiring Amplitude value Amplitude and Phase value Phase corresponding to a preset oscillation signal frequency range based on an array after FFT fast Fourier transform calculation, and respectively calculating a complex real part and a complex imaginary part of an oscillation Pressure signal Pressure and an oscillation Flow signal Flow according to the Amplitude value Amplitude and the Phase value Phase;
s3 specifically comprises:
s31, acquiring the Amplitude value Amplitude and the Phase value Phase corresponding to the frequency range of the oscillation signal of 5 Hz-30 Hz;
s32, respectively calculating a complex real part and a complex imaginary part of the oscillation Pressure signal Pressure and the oscillation Flow signal Flow according to a first complex calculation formula and the Amplitude and the Phase value Phase; wherein, the first complex calculation formula is:
Pressure(f)＝PressAmplitude(f)*Cos(PressPhase*PI()/180)+jPressAmplitude(f)*Sin(PressPhase*PI()/180)＝a+jb；
Flow(f)＝FlowAmplitude(f)Cos(FlowPhase*PI()/180)+jFlowAmplitude(f)*Sin(FlowPhase*PI()/180)＝c+jd；
calculating the complex number of the respiratory impedance according to a second complex number calculation formula; wherein the second complex calculation formula is:
zrs (f) =pressure (f)/Flow (f) =real impedance+imaginary impedance;
wherein Zrs (f) is respiratory impedance, real part of impedance= (a×c+b×d)/(c×2+d×2); impedance imaginary = (b x c-a x d)/(c 2+ d 2);
and S4, calculating and generating a complex number of respiratory impedance corresponding to each frequency according to the oscillation Pressure signal Pressure and the complex real part and the complex imaginary part of the oscillation Flow signal Flow.
2. The forced oscillation-based respiratory impedance calculation method according to claim 1, wherein S2 specifically comprises:
s21, acquiring environmental parameters for BTPS body temperature and environmental pressure correction recorded by the respiratory impedance testing device;
s22, after the respiratory impedance testing device completes oscillation testing, converting the mixed flow signal from ATPS ambient temperature and ambient pressure to BTPS body temperature and ambient pressure; the conversion calculation formula is as follows:
flow btps=flow ATPS BTPS conversion coefficient;
wherein BTPS conversion coefficient= (atmospheric pressure PB-ambient temperature Water vapor partial pressure Prt Water)/(atmospheric pressure PB-body temperature Water vapor partial pressure Pbt Water) ×273+37 ℃ body temperature bt)/(273+ambient temperature rt);
s23, FFT fast Fourier transform calculation is carried out on the separated array.
3. The forced oscillation-based respiratory impedance calculation method according to claim 1, wherein the calculation method further comprises:
s5, calculating the total respiratory impedance corresponding to the frequency of the 5Hz oscillating signal according to a total respiratory impedance calculation formula; wherein, the total respiratory impedance calculation formula is:
zrs-5 hz=sqrt (real part of impedance ≡2+ imaginary part of impedance ≡2);
s6, calculating a phase angle corresponding to the frequency of the 5Hz oscillating signal according to a phase angle calculation formula; wherein, the phase angle calculation formula is:
phase angle dPhase = phase pressure phase of pressure-phase flow of flow;
s7, respectively obtaining total viscous air passage resistance R5, central air passage resistance R20 and peripheral elastic resistance X5; the total resistance R5 of the viscous air passage is equal to the real part of respiratory impedance corresponding to the 5Hz oscillating signal frequency, the resistance R20 of the central air passage is equal to the real part of respiratory impedance corresponding to the 20Hz oscillating signal frequency, and the peripheral elastic resistance X5 is equal to the imaginary part of respiratory impedance corresponding to the 5Hz oscillating signal frequency.
4. The forced oscillation-based respiratory impedance calculation method according to claim 1, wherein the calculation method further comprises:
s8, acquiring a resonance frequency Fres according to the X-ray of the imaginary part of the respiratory impedance; wherein the corresponding frequency of the intersection point of the respiratory impedance imaginary part X line and the zero-point line is the resonance frequency Fres.
5. The forced oscillation-based respiratory impedance calculation method of claim 4, wherein the calculation method further comprises:
s9, calculating reactance area AX according to the respiratory impedance imaginary part X line; the reactance area AX is equal to the area formed by surrounding the respiratory impedance imaginary part X line below the zero line.
6. A breath impedance computing device based on forced oscillation for implementing the breath impedance computing method based on forced oscillation of any of claims 1-5, the computing device comprising:
a mixed signal acquisition unit configured to: after the breath impedance testing device based on forced oscillation starts an oscillation test, a tested mixed pressure signal and a mixed flow signal are obtained;
a conversion calculation unit configured to: generating a preset number of separation arrays according to the mixed pressure signals and the mixed flow signals, and performing FFT (fast Fourier transform) calculation on the separation arrays;
an oscillation signal complex calculation unit for: acquiring Amplitude and Phase value Phase corresponding to a preset oscillation signal frequency range based on an array after FFT fast Fourier transform calculation, and respectively calculating a complex real part and a complex imaginary part of an oscillation Pressure signal Pressure and an oscillation Flow signal Flow according to the Amplitude and the Phase value Phase;
a respiratory impedance complex calculation unit for: and calculating and generating a complex number of respiratory impedance corresponding to each frequency according to the oscillation Pressure signal Pressure and the complex real part and the complex imaginary part of the oscillation Flow signal Flow.
7. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the steps of the forced oscillation based breathing impedance calculation method according to any of claims 1-5 when the computer program is executed.
8. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the forced oscillation based breathing impedance calculation method of any of claims 1-5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310789822.1A CN116831558B (en) | 2023-06-30 | 2023-06-30 | Breath impedance calculation method and calculation device based on forced oscillation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310789822.1A CN116831558B (en) | 2023-06-30 | 2023-06-30 | Breath impedance calculation method and calculation device based on forced oscillation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116831558A CN116831558A (en) | 2023-10-03 |
| CN116831558B true CN116831558B (en) | 2024-03-29 |
Family
ID=88168330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310789822.1A Active CN116831558B (en) | 2023-06-30 | 2023-06-30 | Breath impedance calculation method and calculation device based on forced oscillation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116831558B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0373585A1 (en) * | 1988-12-13 | 1990-06-20 | Schumann, Klaus, Prof. Dr. med. | Determination of respiratory tract impedance by means of oscillation |
| US6142952A (en) * | 1997-10-29 | 2000-11-07 | The Board Of Regents, The University Of Texas System | Method and apparatus for detection and diagnosis of airway obstruction degree |
| CN101511417A (en) * | 2006-08-30 | 2009-08-19 | 雷斯梅德有限公司 | Distinguishing closed and open respiratory airway apneas by complex admittance values |
| CN102488521A (en) * | 2011-12-09 | 2012-06-13 | 东莞理工学院 | Medical respiration monitor respiratory resistance value calculating device |
| CN113558659A (en) * | 2021-07-30 | 2021-10-29 | 重庆安酷科技有限公司 | High-precision ultrasonic lung function detector and detection method thereof |
| CN115702786A (en) * | 2021-08-11 | 2023-02-17 | 深圳市美好创亿医疗科技股份有限公司 | Respiratory impedance detection method and system |
-
2023
- 2023-06-30 CN CN202310789822.1A patent/CN116831558B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0373585A1 (en) * | 1988-12-13 | 1990-06-20 | Schumann, Klaus, Prof. Dr. med. | Determination of respiratory tract impedance by means of oscillation |
| US6142952A (en) * | 1997-10-29 | 2000-11-07 | The Board Of Regents, The University Of Texas System | Method and apparatus for detection and diagnosis of airway obstruction degree |
| CN101511417A (en) * | 2006-08-30 | 2009-08-19 | 雷斯梅德有限公司 | Distinguishing closed and open respiratory airway apneas by complex admittance values |
| CN102488521A (en) * | 2011-12-09 | 2012-06-13 | 东莞理工学院 | Medical respiration monitor respiratory resistance value calculating device |
| CN113558659A (en) * | 2021-07-30 | 2021-10-29 | 重庆安酷科技有限公司 | High-precision ultrasonic lung function detector and detection method thereof |
| CN115702786A (en) * | 2021-08-11 | 2023-02-17 | 深圳市美好创亿医疗科技股份有限公司 | Respiratory impedance detection method and system |
Non-Patent Citations (3)
| Title |
|---|
| 一种便携式强迫振荡呼吸阻抗测试仪的设计与实现;周垂柳等;生物医学工程杂志;第33卷(第5期);951-957 * |
| 强迫振荡技术在无创正压通气中的应用研究;王华;广州医学院硕士论文;全文 * |
| 脉冲振荡肺功能测定慢性注水性肺疾病呼吸阻抗的临床应用;李国栋;青岛大学硕士论文;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116831558A (en) | 2023-10-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4333476A (en) | Comprehensive pulmonary measurement technique | |
| Kaczka et al. | Oscillation mechanics of the respiratory system: applications to lung disease | |
| AU2011325872B2 (en) | Acoustic detection mask systems and/or methods | |
| CN105662345B (en) | heartbeat signal processing method, device and system | |
| US20170055878A1 (en) | Method and system for respiratory monitoring | |
| CA2464029A1 (en) | Non-invasive ventilation monitor | |
| CN110115596A (en) | Lungs sound monitoring device and its lungs sound monitoring method | |
| CN104523262A (en) | Sleep quality detection method based on electrocardiosignals | |
| Van Erck et al. | Measurement of respiratory function by impulse oscillometry in horses | |
| CN106267492A (en) | A kind of Multifunctional internal medicine clinic breathing equipment | |
| Schlegelmilch et al. | Pulmonary function testing | |
| Hao et al. | Dynamic characteristics of a mechanical ventilation system with spontaneous breathing | |
| CN114587347A (en) | Lung function detection method, system, device, computer equipment and storage medium | |
| CN108685575A (en) | Respiratory ft tive resistance test method and device | |
| CN116831558B (en) | Breath impedance calculation method and calculation device based on forced oscillation | |
| GB2055046A (en) | Determining hypersensitivity of the respiratory system | |
| JP2014226422A (en) | Respiratory function testing device, program, and recording medium | |
| Awan et al. | Use of a vortex whistle for measures of respiratory capacity | |
| Reinhold et al. | Validation of impulse oscillometry in Friesian and Blue Belgian calves with respect to changes in extrathoracic upper airway resistance | |
| CN207640405U (en) | Respiratory ft tive resistance test device | |
| Marchal et al. | Forced oscillation technique | |
| CN208065176U (en) | Forced oscillation pulmonary function test (pft) device | |
| Bogomolov et al. | Mathematical justification of the acoustic method for measuring the impedance of the respiratory tract | |
| Bizzotto et al. | A portable fan-based device for evaluating lung function in horses by the forced oscillation technique | |
| Muthusamy et al. | An overview of respiratory airflow estimation techniques: Acoustic vs non-acoustic |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |