CN104739425A - Optical non-invasive detection method for oxygen saturation of mixed venous blood and oxygen saturation of central venous blood - Google Patents

Abstract

The invention discloses an optical non-invasive detection method for oxygen saturation of mixed venous blood and oxygen saturation of central venous blood. Infrared light is adopted, an absorption spectrum of reflected light is measured, and specific mixed and central vein calculation methods are provided. Compared with existing testing methods for blood oxygen saturation, the optical non-invasive detection method not only achieves non-invasive detection but also can achieve real-time continuous monitoring. The specific algorithms are simple, effective and easy to achieve. During measurement, any part of a human body does not need to be clamped, only the body surface needs to be attached to, then the purpose can be achieved by measuring the absorption spectrum of the reflected light, a patient feels more comfortable during measurement, and measurement is simpler and more convenient. Besides, when the oxygen saturation of central venous blood is measured, jugular veins and subclavian veins are preferably selected for a target deep-layer vascular structure, and measurement is more accurate.

Description

The optics non-invasive detection methods of mixing and central vein oxygen saturation

Technical field

The invention belongs to technical field of medical instruments, particularly a kind of method of mixing and central vein blood oxygen saturation.

Background technology

Spectrometric techniques (Near Infrared Spectroscopy is called for short NIRS) is a kind of noinvasive, continuous, real-time optical diagnostic method, it has different absorption spectrum feature based on detected tissue oxygen conjunction hemoglobin and reduced hemoglobin in near-infrared spectra district, select suitable wavelength, calculate the light intensity attenuation of two or more wavelength, just can be asked by absorption law and calculate reduced hemoglobin (Hb) and HbO2 Oxyhemoglobin (HbO ₂) content.

See from Fig. 1, near infrared light region, along with the wavelength of light increases, Hb and HbO ₂absorptance present different variation tendencies, but Hb and HbO ₂an isobestic point is had near wavelength 805nm.Now general with the near infrared light of 760nm and 850nm two wavelength for medium, obtain blood oxygen information.

Mixed venous oxygen saturation (SvO ₂) refer to the blood oxygen saturation of superior and inferior vena cava blood after right heart mixing, depend on that body tissue's oxygen is for (DO ₂) and oxygen consumption (VO ₂) equilibrium condition therebetween.But, SvO ₂mensuration needs to place pulmonary artery catheter (PAC), but this operational risk benefit than still exists dispute at present, does not study and confirms that this operation can improve patient's prognosis, in addition, places PAC and sometimes has difficulties.SvO ₂with central vein blood oxygen saturation (ScvO ₂) there is physiological correlations therebetween, under physiological conditions the former always low after in person 2% ~ 3%, this closes relevant with blood at the deoxidation of coronary sinus, although the two is numerically different, the two always parallel change, therefore, monitoring ScvO ₂become and measure SvO ₂alternative means.

SvO ₂it is the sensitive indicator of the reflection whole body oxygen equilibrium of supply and demand.But adopt this index to carry out should be taken into account physiological compensatory phenomenon when patient with severe symptoms evaluates, namely internal body viscera oxygen is for can be compensatory by what reduce that peripheral circulation makes impaired internal organs blood flow be maintained when occurring abnormal.Different from mixed venous oxygen saturation, central vein oxygen saturation (ScvO ₂) be the index that directly reflection main organs oxygen supply and demand above the waist changes, therefore, ScvO ₂occurring abnormal, showing that internal organs oxygen is for being on the hazard, and needs actively to give treatment to.

With reference to prior art, SvO ₂measure and mostly need to place pulmonary artery catheter (PAC), but than still there is dispute at present in the risk benefit of this operation, and ScvO ₂mensuration then generally use with visual optical fiber central venous catheter or use the central venous catheter of traditional repeated blood sampling, above two kinds of methods all belong to the method having wound.

At present, CN103961110A in Chinese patent, CN103932713A, the patents such as CN103096791A all have contact in various degree with the present invention, but most of patent is all use fingerstall to disclose " bio signal Analytical system and bio signal determinator " to carry out signals collecting such as Chinese patent CN103961110A, and being limited in scope of acquired signal, when processing critical patient, due to the situation of the peripheral circulation minimizing that the compensatory phenomenon of its physiological causes, this kind of method seems unable to do what one wishes.And disclosing in " a kind of reflectance oximetry " (its disclosure part be incorporated herein as a reference in) although this invention can overcome a upper class and invent problem in the measuring range that faces at comparatively early disclosed China Patent No. CN103932713A, it does not provide and mixes and the measuring method of central venous oxygen saturation.

And Chinese patent CN103096791A discloses " non-invasive measurement of blood oxygen saturation ", itself and relation of the present invention are the tightst, CN103096791A gives the measuring method of mixing and central vein blood oxygen saturation, and the preferred wavelength range of use is about 1045nm to 1055nm and about 1085nm to 1095nm.But this invention unexposed or hint mixing and central vein blood oxygen saturation the specific algorithm of measuring method, and wavelength is relatively poor for the penetration of skin at the light of more than 1000nm, can not measure the blood oxygen saturation compared with deep location relatively accurately.

Summary of the invention

For solving the problems of the technologies described above, the present invention proposes the optics non-invasive detection methods of a kind of mixing and central vein oxygen saturation.

The technical scheme that the present invention adopts for its technical problem of solution is: the optics non-invasive detection methods of mixing and central vein oxygen saturation, specifically comprises the following steps:

The initial outgoing voltage U that A, basis record ₀(λ) and outgoing voltage signal in time t change function U (λ, t), calculate transmitted light intensity than I (λ, t)/I ₀(λ),

Wherein, I (λ, t) is transmitted light intensity, I ₀(λ) be initial transmission light intensity;

B, the transmitted light intensity ratio calculated according to steps A, calculate the knots modification Δ μ that biological tissue is the absorption coefficient of light under the near infrared light of λ at wavelength _a(λ, t);

C, according to HbO ₂with the absorption coefficient of light μ of Hb and biological tissue _athe linear relationship of (λ, t), draws HbO ₂Δ [HbO is respectively with the differential transfer data of Hb ₂] and Δ [Hb];

D, according to Fourier transformation, by the HbO obtained in step C ₂with the differential transfer data Δ [HbO of Hb ₂] and Δ [Hb] transform to frequency domain and obtain Δ [HbO ₂] _fwith Δ [Hb] _f, then to the result Δ [HbO after Fourier transformation process ₂] _fwith Δ [Hb] _frevise;

Result Δ [HbO after E, the Fourier transformation process that obtained by narrow band filter treatment step D ₂] _fwith Δ [Hb] _f, at Δ [HbO ₂] _fwith Δ [Hb] _ffrequency domain in select the signal produced within the scope of predeterminated frequency by the respiratory frequency of measured, zero phase-shift Filtering Processing is carried out to the signal selected, obtains Δ [HbO ₂] _rwith Δ [Hb] _r;

F, according to the Δ [HbO obtained in step e ₂] _rwith Δ [Hb] _r, the meansigma methods calculating their amplitude is respectively and according to the mean value calculation ScvO of the amplitude calculated ₂or SvO ₂.

Further, described step e also comprises E0: data verification, by calculating HbO respectively ₂with the signal to noise ratio of Hb, the result obtained and predetermined threshold value are compared, if be all more than or equal to predetermined threshold value, then data are effective, otherwise data invalid.

Further, when measuring the position of peripheral circulation, method according to claim 1 obtains SvO ₂value, when measuring central vein position or groin position in neck, method according to claim 1 obtains ScvO ₂value.

Further, also comprise steps A 0: launch near infrared light by light source, described light source at least comprises one, and each light source at least launches the near infrared light of two kinds of wavelength.

Further, when comprising a light source, this light source comprises two different wave length λ ₁, λ ₂infrared light, then obtain the knots modification Δ μ of the absorption coefficient of light _a(λ ₁, t), Δ μ _a(λ ₂, t) as follows:

$\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_1,t)=\frac{{\log }_{10}(I({\mathrm{\λ}}_1,t)/I_0\left({\mathrm{\λ}}_1\right))}{d\×\mathrm{DPF}}---(2.a)$

$\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_2,t)=\frac{{\log }_{10}(I({\mathrm{\λ}}_2,t)/I_0\left({\mathrm{\λ}}_2\right))}{d\×\mathrm{DPF}}---(2.b)$

Wherein, I (λ ₁, t), I (λ ₂, be t) wavelength be λ ₁, λ ₂the transmitted light intensity of near infrared light, I ₀(λ ₁), I ₀(λ ₂) wavelength is λ ₁, λ ₂the initial transmitted light intensity of near infrared light, d is the distance that light transmits in biological tissues, and DPF is derivative paths length factor.

Further, when light source launches two kinds of wavelength X ₁, λ ₂near infrared light time, draw HbO ₂with the differential transfer data Δ [HbO of Hb ₂], the arithmetic expression of Δ [Hb] is:

$\mathrm{\Δ}\left[\mathrm{Hb}{O}_2\right]=\frac{\begin{array}{c}[{{\mathrm{\ϵ}}_{\mathrm{hb}}}^2\left({\mathrm{\λ}}_1\right)+{{\mathrm{\ϵ}}_{\mathrm{hb}}}^2\left({\mathrm{\λ}}_2\right)][{\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_1,t)+{\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_2,t)]-\\ [{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)+{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)][{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right)\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_1,t)+{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right)\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_2,t)]\end{array}}{{[{{\mathrm{\ϵ}}_{\mathrm{hb}}}^2\left({\mathrm{\λ}}_1\right)+{{\mathrm{\ϵ}}_{\mathrm{hb}}}^2\left({\mathrm{\λ}}_2\right)][{{\mathrm{\ϵ}}_{\mathrm{hbO}2}}^2\left({\mathrm{\λ}}_1\right)+{{\mathrm{\ϵ}}_{\mathrm{hbO}2}}^2\left({\mathrm{\λ}}_2\right)]-[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)+{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)]}^2}---(3.a)$

$\mathrm{\Δ}\left[\mathrm{Hb}\right]=\frac{\begin{array}{c}[{{\mathrm{\ϵ}}_{\mathrm{hbo}2}}^2\left({\mathrm{\λ}}_1\right)+{{\mathrm{\ϵ}}_{\mathrm{hbO}2}}^2\left({\mathrm{\λ}}_2\right)][{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right)\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_1,t)+{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right)\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_2,t)]-\\ [{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)+{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)][{\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_1,t)+{\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)\mathrm{\Δ}{\mathrm{\μ}}_a({\mathrm{\λ}}_2,t)]\end{array}}{{[{{\mathrm{\ϵ}}_{\mathrm{hb}}}^2\left({\mathrm{\λ}}_1\right)+{{\mathrm{\ϵ}}_{\mathrm{hb}}}^2\left({\mathrm{\λ}}_2\right)][{{\mathrm{\ϵ}}_{\mathrm{hbO}2}}^2\left({\mathrm{\λ}}_1\right)+{{\mathrm{\ϵ}}_{\mathrm{hbO}2}}^2\left({\mathrm{\λ}}_2\right)]-[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)+{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)]}^2}---(4.a)$

Wherein, ε _hbO2(λ ₁), ε _hbO2(λ ₂) be wavelength be respectively λ ₁, λ ₂time HbO ₂molar absorption coefficient, ε _hb(λ ₁), ε _hb(λ ₂) be wavelength be respectively λ ₁, λ ₂time Hb molar absorption coefficient.

Further, in described step D to the result Δ [HbO after Fourier transformation process ₂] _f, Δ [Hb] _frevise, be specially the result Δ [HbO after by Fourier transformation process ₂] _f, Δ [Hb] _frevise the amplification of Fourier transformation respectively divided by L/2, realized by following formula:

$f\left\{\mathrm{\Δ}\right[\mathrm{Hb}{O}_2\left]\right\}=\frac{\mathrm{\Δ}{\left[\mathrm{Hb}{O}_2\right]}_f}{(L/2)}---(5.a)$

$f\left\{\mathrm{\Δ}\right[\mathrm{Hb}\left]\right\}=\frac{\mathrm{\Δ}{\left[\mathrm{Hb}\right]}_f}{(L/2)}---(5.b)$

Wherein, Δ [HbO ₂] _ffor to Δ [HbO ₂] carry out Fourier transformation, Δ [Hb] _ffor carrying out Fourier transformation to Δ [Hb], f{ Δ [HbO ₂] and f{ Δ [Hb] be through revised Δ [HbO ₂] and Δ [Hb] Fourier transformation result, L is sampling number.

Beneficial effect of the present invention: the optics non-invasive detection methods of mixing of the present invention and central vein oxygen saturation, adopt infrared light, by measuring the absorption spectrum of reflected light, and concrete computational methods, compared with the existing method of testing about blood oxygen saturation, method provided by the invention not only achieves Non-invasive detection, and can accomplish that real-time continuous is monitored, specific algorithm provided by the present invention, effectively simple, be easy to realize, and do not need any position of clamping human body when the present invention measures, only need to touch body surface then just can be achieved the goal by the absorption spectrum measuring reflected light, measure more comfortable easy, when entreating venous oxygen saturation in addition in the measurements, the preferred internal jugular vein of target deep-level blood vessel structure and subclavian vein, it is more accurate to measure.In the present invention, mixed venous oxygen saturation is the same with the algorithm of central vein oxygen saturation, different unlike the position measured.The probe measuring mixed venous oxygen saturation should be placed on the position of peripheral circulation, preferred position is at brain or frontal lobe, and probe can only be placed in two positions when measuring central vein oxygen saturation, one is in neck near central vein, and another is near groin.

Accompanying drawing explanation

Fig. 1 is Hb and HbO ₂absorptance with wavelength change figure.

Fig. 2 is the solution of the present invention flow chart.

The experimental provision figure that Fig. 3 provides for the embodiment of the present invention.

Outgoing voltage curve chart over time measured by the optic probe that Fig. 4 provides for the embodiment of the present invention.

The HbO that Fig. 5 provides for the embodiment of the present invention ₂with the differential transfer data curve chart over time of Hb.

The HbO that Fig. 6 provides for the embodiment of the present invention ₂with the spectrogram of Hb after fast Fourier transform.

HbO after the Filtering Processing that Fig. 7 provides for the embodiment of the present invention ₂with the differential transfer data change curve in time of Hb.

Fig. 8 judges the protocol procedures figure of signal to noise ratio for band that the embodiment of the present invention provides.

Δ [the HbO that about the respiratory frequency that Fig. 9 provides for the embodiment of the present invention, the frequency band of 1% is corresponding ₂] _rwith Δ [Hb] _rwith the comparison diagram of other frequency band.

Detailed description of the invention

For making content of the present invention clearly, now with the following Examples, and by reference to the accompanying drawings technology contents of the present invention is described in detail.

Because mixed venous oxygen saturation is the same with the algorithm of central vein oxygen saturation, different unlike the position measured.The probe measuring mixed venous oxygen saturation should be placed on the position of peripheral circulation, preferred position is at brain or frontal lobe, and probe can only be placed in two positions when measuring central vein oxygen saturation, one is in neck near central vein, and another is near groin.Therefore the present embodiment mainly introduces the measuring method of central vein oxygen saturation, and the measurement of mixed venous oxygen saturation, with reference to the measurement of central vein oxygen saturation, only need change measuring point.

Be illustrated in figure 2 the solution of the present invention flow chart, the present invention specifically comprises following steps:

The initial outgoing voltage U that A, basis record ₀(λ) and outgoing voltage signal in time t change function U (λ, t), calculate transmitted light intensity than I (λ, t)/I ₀(λ);

Wherein, I (λ, t) is transmitted light intensity, I ₀(λ) be initial transmission light intensity;

B, the transmitted light intensity ratio calculated according to steps A, calculate the knots modification Δ μ of the absorption coefficient of light of biological tissue under wavelength is the near infrared light of λ _a(λ, t);

C, according to HbO ₂with the absorption coefficient of light μ of Hb and biological tissue _athe linear relationship of (λ, t), draws HbO ₂Δ [HbO is respectively with the differential transfer data of Hb ₂] and Δ [Hb];

D, according to Fourier transformation, by the HbO obtained in step C ₂with the differential transfer data Δ [HbO of Hb ₂] and Δ [Hb] transform to frequency domain and obtain Δ [HbO ₂] _fwith Δ [Hb] _f, then to the result Δ [HbO after Fourier transformation process ₂] _fwith Δ [Hb] _frevise;

Result Δ [HbO after E, the Fourier transformation process that obtained by narrow band filter treatment step D ₂] _fwith Δ [Hb] _f, at Δ [HbO ₂] _fwith Δ [Hb] _ffrequency domain in select the signal produced within the scope of predeterminated frequency by the respiratory frequency of measured, zero phase-shift Filtering Processing is carried out to the signal selected, obtains Δ [HbO ₂] _rwith Δ [Hb] _r;

F, according to the Δ [HbO obtained in step e ₂] _rwith Δ [Hb] _r, calculate the meansigma methods of their amplitude and according to the mean value calculation ScvO of the amplitude calculated ₂.Mentioned in background technology, SvO ₂with central vein blood oxygen saturation (ScvO ₂) there is physiological correlations therebetween, under physiological conditions the former always low after in person 2% ~ 3%, this closes relevant with blood at the deoxidation of coronary sinus, although the two is numerically different, the two always parallel change, therefore, monitoring ScvO ₂become and measure SvO ₂alternative means.So measuring center venous oxygen saturation is just equal to measurement mixed venous oxygen saturation.

Embodiment one

Detector has two light sources, two wavelength in the present embodiment.

In step during specific implementation, two light sources launching two kinds of wavelength X near infrared lights and the light-sensitive detector series that can detect the optical attenuation change that detected part tissue light transmission is returned constitute an optical detector, as shown in Figure 3, the representative value of two kinds of wavelength is respectively λ here ₁=735nm and λ ₂=850nm.In this example, this optical detector is placed in measured's cervical region to measure, be abscissa with time after having measured, voltage is vertical coordinate, make outgoing voltage that optical detector measures over time curve as shown in Figure 4, wherein subscript 1,2 represents light source 1 and light source 2 respectively.By function U (λ, t) and the initial outgoing voltage U of the t change in time of measured outgoing voltage signal ₀(λ) ratio, calculates transmitted light intensity than I (λ, t)/I ₀(λ):

I(λ,t)/I ₀(λ)＝U(λ,t)/U ₀(λ)

Wherein, I (λ, t) and I ₀(λ) be transmitted light intensity and initial transmission light intensity.Initial outgoing voltage U is chosen in this embodiment ₀(λ) the average outgoing magnitude of voltage of representative value for obtain for first 30 seconds.

When step B specific implementation, the transmitted light intensity calculated by steps A is than calculating the knots modification Δ μ that wavelength is the absorption coefficient of light of biological tissue under the near infrared light of λ _a(λ, t), obtain the knots modification of the absorption coefficient of light of two groups of data in this instance respectively:

$\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_1,t)}_1=\frac{{\log }_{10}(I{({\mathrm{\λ}}_1,t)}_2/I_0{\left({\mathrm{\λ}}_1\right)}_1)}{d_2\×\mathrm{DPF}}$

$\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_1,t)}_2=\frac{{\log }_{10}(I{({\mathrm{\λ}}_1,t)}_2/I_0{\left({\mathrm{\λ}}_1\right)}_2)}{d_2\×\mathrm{DPF}}$

$\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_2,t)}_1=\frac{{\log }_{10}(I{({\mathrm{\λ}}_2,t)}_1/I_0{\left({\mathrm{\λ}}_2\right)}_1)}{d_1\×\mathrm{DPF}}$

$\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_2,t)}_2=\frac{{\log }_{10}(I{({\mathrm{\λ}}_2,t)}_2/I_0{\left({\mathrm{\λ}}_2\right)}_2)}{d_2\×\mathrm{DPF}}$

Wherein, Δ μ _a(λ ₁, t) ₁with Δ μ _a(λ ₂, t) ₁represent that probe is at light source 1 two wavelength (λ respectively ₁, λ ₂) (under the knots modification of the absorption coefficient of light that calculates, Δ μ _a(λ ₁, t) ₂with Δ μ _a(λ ₂, t) ₂then represent that probe is at light source 2 two wavelength (λ respectively ₁, λ ₂) under the knots modification of the absorption coefficient of light that calculates, d ₁, d ₂the distance between two light sources to light-sensitive detector respectively; DPF is derivative paths length factor; I (λ ₁, t) ₁, I (λ ₂, t) ₁the transmitted light intensity calculated under light source 1 two wavelength, I (λ ₁, t) ₂, I (λ ₂, t) ₂it is the transmitted light intensity calculated under light source 2 two wavelength; I ₀(λ ₁) ₁, I ₀(λ ₂) ₁the initial transmitted light intensity calculated under light source 1 two wavelength, I ₀(λ ₁) ₂, I ₀(λ ₂) ₂the initial transmitted light intensity calculated under light source 2 two wavelength.

When step C specific implementation, pass through HbO ₂with the absorption coefficient of light μ of Hb and biological tissue _athe linear relationship of (λ, t), obtains HbO ₂with the differential transfer data Δ [HbO of Hb ₂], Δ [Hb].During specific implementation, the first differential transfer data of calculating and light source 1 correspondence:

$\mathrm{\Δ}{\left[\mathrm{Hb}{O}_1\right]}_1=\frac{\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right)\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_2,t)}_1\right]-\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right)\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_1,t)}_1\right]}{\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)\right]-\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)\right]}$

$\mathrm{\Δ}{\left[\mathrm{Hb}\right]}_1=\frac{\left[{\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_1,t)}_1\right]-\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right)\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_2,t)}_1\right]}{\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)\right]-\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)\right]}$

Wherein, ε _hbO2(λ ₁), ε _hbO2(λ ₂) be wavelength be respectively λ ₁, λ ₂time HbO ₂molar absorption coefficient, ε _hb(λ ₁), ε _hb(λ ₂) be wavelength be respectively λ ₁, λ ₂time Hb molar absorption coefficient; Δ μ _a(λ ₁, t) ₁for wavelength is λ ₁time the absorption coefficient of light knots modification, Δ μ _a(λ ₂, t) ₁for wavelength is λ ₂time the absorption coefficient of light knots modification.

Then the differential transfer data of calculating and light source two correspondence are as follows below:

$\mathrm{\Δ}{\left[\mathrm{Hb}{O}_2\right]}_2=\frac{\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right)\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_2,t)}_2\right]-\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right)\frac{{\log }_{10}(I{({\mathrm{\λ}}_2,t)}_2/I_0{\left({\mathrm{\λ}}_1\right)}_1)}{d_2\×\mathrm{DPF}}\right]}{\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)\right]-\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)\right]}$

$\mathrm{\Δ}{\left[\mathrm{Hb}\right]}_2=\frac{\left[{\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)\mathrm{\Δ}{\mathrm{\μ}}_a{({\mathrm{\λ}}_1,t)}_2\right]-\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right)\frac{{\log }_{10}(I{({\mathrm{\λ}}_1,t)}_2/I_0{\left({\mathrm{\λ}}_2\right)}_1)}{d_2\×\mathrm{DPF}}\right]}{\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_1\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_2\right)\right]-\left[{\mathrm{\ϵ}}_{\mathrm{hb}}\left({\mathrm{\λ}}_2\right){\mathrm{\ϵ}}_{\mathrm{hbO}2}\left({\mathrm{\λ}}_1\right)\right]}$

Wherein, Δ μ _a(λ ₁, t) ₂for wavelength is λ ₁time the absorption coefficient of light knots modification, Δ μ _a(λ ₂, t) ₂for wavelength is λ ₂time the absorption coefficient of light knots modification; After calculating completes, take time as abscissa, Hb or HbO ₂differential transfer data be that vertical coordinate makes curve chart as shown in Figure 5, wherein subscript 1,2 respectively corresponding light source 1 and light source 2.

Use Fourier transformation to obtain HbO when step D specific implementation ₂with the differential transfer data signal numerical value in a frequency domain of Hb.

To Δ [HbO ₂] and Δ [Hb] carry out Fourier transformation and obtain Δ [HbO ₂] _fwith Δ [Hb] _f, the result then after Fourier transformation process revises the amplification of Fourier transformation divided by L/2:

$f\left\{\mathrm{\Δ}\right[\mathrm{Hb}{O}_2\left]\right\}=\frac{\mathrm{\Δ}{\left[\mathrm{Hb}{O}_2\right]}_f}{(L/2)}$

$f\left\{\mathrm{\Δ}\right[\mathrm{Hb}\left]\right\}=\frac{\mathrm{\Δ}{\left[\mathrm{Hb}\right]}_f}{(L/2)}$

Wherein, f{ Δ [HbO ₂] and f{ Δ [Hb] be through revised Δ [HbO ₂] and Δ [Hb] Fourier transformation result.L is sampling number, conveniently carries out Fourier transformation operation, and usual L gets the integer power of 2.

Fig. 6 is HbO in this example ₂with the spectrogram of Hb after Fourier transformation.Wherein abscissa is frequency, and vertical coordinate is F (HbO ₂) and F (Hb), subscript 1,2 represents light source 1 and light source 2 respectively.

The band filter processing signals that one narrower is utilized, at HbO when the specific implementation of step e ₂select preferred typical frequencies with in the frequency domain of the differential transfer data signal of Hb---about respiratory frequency 1% frequency band produce signal (namely the predeterminated frequency scope of the present embodiment is: about respiratory frequency 1% frequency band).In order to accurately measure and calculate mixed venous oxygen saturation (SvO ₂) and central vein oxygen saturation (ScvO ₂), adopt the signal that this frequency produces---HbO ₂with the differential transfer data Δ [HbO of Hb ₂] _r, Δ [Hb] _rcarry out calculating below.

In order to obtain Δ [HbO ₂] _rwith Δ [Hb] _r, to Δ [HbO ₂] and Δ [Hb] get passband about respiratory frequency 1% the zero phase-shift filtering of frequency separation.

Take time as abscissa, the HbO after processed ₂be vertical coordinate with Hb differential transfer data, as shown in Figure 7.

By Δ [HbO in step F ₂] _rwith Δ [Hb] _rsolve SvO ₂detailed process as follows:

Obtain Δ [HbO ₂] _rwith Δ [Hb] _ramplitude

oaΔ[HbO ₂] _r＝|Δ[HbO ₂] _r|

oaΔ[Hb] _r＝|Δ[Hb] _r|

Δ [the HbO obtained ₂] _rwith Δ [Hb] _ramplitude be in time t change function, they are averaged

$\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}{O}_2\right]}_r}=\frac{{\mathrm{\Σ}}_t\mathrm{oa\Δ}{\left[\mathrm{Hb}{O}_2\right]}_r}{t}$

$\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}\right]}_r}=\frac{{\mathrm{\Σ}}_t\mathrm{oa\Δ}{\left[\mathrm{Hb}\right]}_r}{t}$

Finally utilize and ask ScvO ₂computing formula computing obtain

$\mathrm{Scv}{O}_2=\frac{\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}\right]}_r}}{\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}\right]}_r}+\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}{O}_2\right]}_r}}\×100\%$

In this instance, the central vein oxygen saturation that can calculate under two light sources is as follows:

$\mathrm{Scv}{O}_2\_1=\frac{\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}\right]}_{r1}}}{\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}\right]}_{r1}}+\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}{O}_2\right]}_{r1}}}\×100\%$

$\mathrm{Scv}{O}_2\_2=\frac{\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}\right]}_{r2}}}{\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}\right]}_{r2}}+\stackrel{\‾}{\mathrm{oa\Δ}{\left[\mathrm{Hb}{O}_2\right]}_{r2}}}\×100\%$

Wherein subscript 1,2 represents light source 1 and light source 2 respectively.

In the present embodiment, data result of calculation is:

ScvO ₂_1＝0.6906，ScvO ₂_2＝0.7012

Embodiment two

In this example, not get Δ [HbO when utilizing a narrower band filter processing signals ₂] and Δ [Hb] frequency domain in about respiratory frequency 1% the signal that produces of frequency, but appoint the one of getting in other frequency bands.The SvO calculated ₂most all beyond the normal SvO of human body ₂scope.Therefrom select one group as shown in Figure 8, the left side four width figure appoints to get Δ [HbO corresponding to other frequency bands ₂] _rwith Δ [Hb] _r, the right four width figure is the Δ [HbO corresponding to frequency band of about respiratory frequency 1% ₂] _rwith Δ [Hb] _r, gap is obvious.So the measurement SvO that about respiratory frequency, the frequency band of 1% is best suited for ₂and ScvO ₂frequency band.

Embodiment three

In the present embodiment, in computational process, add data verification, its particular flow sheet as shown in Figure 9.Calculate signal to noise ratio formula as follows:

${\mathrm{SNR}}_{\mathrm{Hb}}=\frac{f{\left\{\mathrm{\&Delta;}\right[\mathrm{Hb}\left]\right\}}_{f=r}}{{\mathrm{\&sigma;}}_{f<=r}}$

${\mathrm{SNR}}_{\mathrm{HbO}2}=\frac{f{\left\{\mathrm{\&Delta;}\right[\mathrm{Hb}{O}_2\left]\right\}}_{f=r}}{{\mathrm{\&sigma;}}_{f<=r}}$

Wherein, SNR _hbthe signal to noise ratio of Hb, hbO ₂signal to noise ratio, f{ Δ [Hb] } _f=rbe Δ [Hb] after Fourier transformation at the peak value of respiratory frequency data, σ _f<=rthat Δ [Hb] is being less than the standard deviation of frequency band data of respiratory frequency after Fourier transformation; F{ Δ [HbO ₂] _f=rthen Δ [HbO ₂] after Fourier transformation at the peak value of respiratory frequency data, σ _f<=rΔ [HbO ₂] after Fourier transformation, be less than the standard deviation of frequency band data of respiratory frequency.

Judge that in representative value the present embodiment of SNR, predetermined threshold value value is 2.5, works as SNR _hb>=2.5 and SNR _hbO2illustrate during=>2.5 that the quality of data is better, result of calculation is reliably effective.

Calculate in the present embodiment:

SNR _HbO2_1＝2.9115SNR _Hb_1＝3.1544

SNR _HbO2_2＝2.6909SNR _Hb_2＝4.7726

Obvious signal to noise ratio meets checking requirement, continues subsequent calculations, obtains:

ScvO ₂_1＝0.6956，ScvO ₂_2＝0.7032

In sum, the present invention is based on near-infrared spectrum technique and propose a kind of optics non-invasive detection methods measuring mixing and central vein oxygen saturation, not only can accomplish noinvasive, and can accomplish that real-time continuous is reliably monitored, compensate for the deficiency of existing patient's monitoring technology.

Those of ordinary skill in the art will appreciate that, embodiment described here is to help reader understanding's principle of the present invention, should be understood to that protection scope of the present invention is not limited to so special statement and embodiment.For a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within right of the present invention.

Claims (7)

1. the optics non-invasive detection methods of mixing and central vein oxygen saturation, is characterized in that, specifically comprise the following steps:

The initial outgoing voltage U that A, basis record ₀(λ) and outgoing voltage signal in time t change function U (λ, t), calculate transmitted light intensity than I (λ, t)/I ₀(λ),

Wherein, I (λ, t) is transmitted light intensity, I ₀(λ) be initial transmission light intensity;

B, the transmitted light intensity ratio calculated according to steps A, calculate the knots modification Δ μ that biological tissue is the absorption coefficient of light under the near infrared light of λ at wavelength _a(λ, t);

C, according to HbO ₂with the absorption coefficient of light μ of Hb and biological tissue _athe linear relationship of (λ, t), draws HbO ₂Δ [HbO is respectively with the differential transfer data of Hb ₂] and Δ [Hb];

D, according to Fourier transformation, by the HbO obtained in step C ₂with the differential transfer data Δ [HbO of Hb ₂] and Δ [Hb] transform to frequency domain and obtain Δ [HbO ₂] _fwith Δ [Hb] _f, then to the result Δ [HbO after Fourier transformation process ₂] _fwith Δ [Hb] _frevise;

Result Δ [HbO after E, the Fourier transformation process that obtained by narrow band filter treatment step D ₂] _fwith Δ [Hb] _f, at Δ [HbO ₂] _fwith Δ [Hb] _ffrequency domain in select the signal produced within the scope of predeterminated frequency by the respiratory frequency of measured, zero phase-shift Filtering Processing is carried out to the signal selected, obtains Δ [HbO ₂] _rwith Δ [Hb] _r;

F, according to the Δ [HbO obtained in step e ₂] _rwith Δ [Hb] _r, the meansigma methods calculating their amplitude is respectively and according to the mean value calculation ScvO of the amplitude calculated ₂or SvO ₂.

2. method according to claim 1, is characterized in that, described step e also comprises E0: data verification, by calculating HbO respectively ₂with the signal to noise ratio of Hb, the result obtained and predetermined threshold value are compared, if be all more than or equal to predetermined threshold value, then data are effective, otherwise data invalid.

3. method according to claim 1, is characterized in that, when measuring the position of peripheral circulation, method according to claim 1 obtains SvO ₂value, when measuring central vein position or groin position in neck, method according to claim 1 obtains ScvO ₂value.

4. method according to claim 1, is characterized in that, also comprises steps A 0: launch near infrared light by light source, and described light source at least comprises one, and each light source at least launches the near infrared light of two kinds of wavelength.

5. method according to claim 4, is characterized in that, when comprising a light source, this light source comprises two different wave length λ ₁, λ ₂infrared light, then obtain the knots modification Δ μ of the absorption coefficient of light _a(λ ₁, t), Δ μ _a(λ ₂, t) as follows:

$\mathrm{\&Delta;}{\mathrm{\&mu;}}_a({\mathrm{\&lambda;}}_1,t)=\frac{{\log }_{10}(I({\mathrm{\&lambda;}}_1,t)/I_0\left({\mathrm{\&lambda;}}_1\right))}{d\&times;\mathrm{DPF}}---(2.a)$

${\mathrm{\&Delta;\&mu;}}_a({\mathrm{\&lambda;}}_2,t)=\frac{{\log }_{10}(I({\mathrm{\&lambda;}}_2,t)/I_0\left({\mathrm{\&lambda;}}_2\right))}{d\&times;\mathrm{DPF}}---(2.b)$

Wherein, I (λ ₁, t), I (λ ₂, be t) wavelength be λ ₁, λ ₂the transmitted light intensity of near infrared light, I ₀(λ ₁), I ₀(λ ₂) wavelength is λ ₁, λ ₂the initial transmitted light intensity of near infrared light, d is the distance that light transmits in biological tissues, and DPF is derivative paths length factor.

6. method according to claim 5, is characterized in that, when light source launches two kinds of wavelength X ₁, λ ₂near infrared light time, draw HbO ₂with the differential transfer data Δ [HbO of Hb ₂], the arithmetic expression of Δ [Hb] is:

$\mathrm{\&Delta;}\left[{\mathrm{HbO}}_2\right]=\frac{\begin{array}{c}[{{\mathrm{\&epsiv;}}_{\mathrm{hb}}}^2\left({\mathrm{\&lambda;}}_1\right)+{{\mathrm{\&epsiv;}}_{\mathrm{hb}}}^2\left({\mathrm{\&lambda;}}_2\right)][{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_1\right){\mathrm{\&Delta;\&mu;}}_a({\mathrm{\&lambda;}}_1,t)+{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_2\right){\mathrm{\&Delta;\&mu;}}_a({\mathrm{\&lambda;}}_2,t)]-\\ [{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_1\right){\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_1\right)+{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_2\right){\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_2\right)][{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_1\right){\mathrm{\&Delta;\&mu;}}_a({\mathrm{\&lambda;}}_1,t)+{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_2\right){\mathrm{\&Delta;\&mu;}}_a({\mathrm{\&lambda;}}_2,t)]\end{array}}{[{{\mathrm{\&epsiv;}}_{\mathrm{hb}}}^2\left({\mathrm{\&lambda;}}_1\right)+{{\mathrm{\&epsiv;}}_{\mathrm{hb}}}^2\left({\mathrm{\&lambda;}}_2\right)][{{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}}^2\left({\mathrm{\&lambda;}}_1\right)+{{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}}^2\left({\mathrm{\&lambda;}}_2\right)]-[{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_1\right){\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_1\right)+{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_2\right){\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_2\right){]}^2}---(3.a)$

$\mathrm{\&Delta;}\left[\mathrm{Hb}\right]=\frac{\begin{array}{c}[{{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}}^2\left({\mathrm{\&lambda;}}_1\right)+{{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}}^2\left({\mathrm{\&lambda;}}_2\right)][{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_1\right){\mathrm{\&Delta;\&mu;}}_a({\mathrm{\&lambda;}}_1,t)+{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_2\right){\mathrm{\&Delta;\&mu;}}_a({\mathrm{\&lambda;}}_2,t)]-\\ [{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_1\right){\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_1\right)+{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_2\right){\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_2\right)][{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_1\right){\mathrm{\&Delta;\&mu;}}_a({\mathrm{\&lambda;}}_1,t)+{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_2\right){\mathrm{\&Delta;\&mu;}}_a({\mathrm{\&lambda;}}_2,t)]\end{array}}{[{{\mathrm{\&epsiv;}}_{\mathrm{hb}}}^2\left({\mathrm{\&lambda;}}_1\right)+{{\mathrm{\&epsiv;}}_{\mathrm{hb}}}^2\left({\mathrm{\&lambda;}}_2\right)][{{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}}^2\left({\mathrm{\&lambda;}}_1\right)+{{\mathrm{\&epsiv;}}_{\mathrm{hbO}2}}^2\left({\mathrm{\&lambda;}}_2\right)]-[{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_2\right){\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_2\right)+{\mathrm{\&epsiv;}}_{\mathrm{hb}}\left({\mathrm{\&lambda;}}_2\right){\mathrm{\&epsiv;}}_{\mathrm{hbO}2}\left({\mathrm{\&lambda;}}_2\right){]}^2}---(4.a)$

Wherein, ε _hbO2(λ ₁), ε _hbO2(λ ₂) be wavelength be respectively λ ₁, λ ₂time HbO ₂molar absorption coefficient, ε _hb(λ ₁), ε _hb(λ ₂) be wavelength be respectively λ ₁, λ ₂time Hb molar absorption coefficient.

7. method according to claim 1, is characterized in that, to the result Δ [HbO after Fourier transformation process in described step D ₂] _f, Δ [Hb] _frevise, be specially the result Δ [HbO after by Fourier transformation process ₂] _f, Δ [Hb] _frevise the amplification of Fourier transformation respectively divided by L/2, realized by following formula:

$f\left\{\mathrm{\&Delta;}\right[{\mathrm{HbO}}_2\left]\right\}=\frac{\mathrm{\&Delta;}[{\mathrm{HbO}}_2{]}_f}{(L/2)}---(5.a)$

$f\left\{\mathrm{\&Delta;}\right[\mathrm{Hb}\left]\right\}=\frac{\mathrm{\&Delta;}{\left[\mathrm{Hb}\right]}_f}{(L/2)}---(5.b)$

Wherein, Δ [HbO ₂] _ffor to Δ [HbO ₂] carry out Fourier transformation, Δ [Hb] _ffor carrying out Fourier transformation to Δ [Hb], f{ Δ [HbO ₂] and f{ Δ [Hb] be through revised Δ [HbO ₂] and Δ [Hb] Fourier transformation result, L is sampling number.