CN1223843C - Method for detecting newborn baby partial tissue oxygen saturation under oxygen absorption stimulation - Google Patents

Abstract

The present invention relates to a method for detecting the oxygen saturation of newborn babies' partial brain tissues under the stimulation of oxygen absorption, which belongs to the technical field of biomedical engineering. The present invention is characterized in that three photoelectric receiving tubes jointly arranged in the same straight line and a light source comprising two light emitting diodes are used as a sensor, and on the basis of different spectral characteristics of oxyhemoglobin and reduced hemoglobin in tissue oxygen metabolism, the oxygen saturation of blood of partial tissues is worked out according to rules of the absorption and the scattering of light in tissues. The variation of the oxygen saturation of newborn babies' partial tissues can be detected and worked out under the condition of absorbing pure oxygen in short time. The photoelectric receiving tubes are arranged at equal intervals, and the two light emitting diodes can respectively emit red light and near infrared light. The present invention can sensitively detect the oxygen saturation of blood of newborn babies and newborn patients' partial brain tissues and the varying process of the oxygen saturation of blood.

Description

Oxygen uptake stimulates the detection method of newborn baby local organization oxygen saturation down

Technical field

The detection method of newborn baby local organization oxygen saturation belonged to the biomedical engineering technology field under oxygen uptake stimulated, and related in particular to newborn baby local organization blood oxygen parameter detecting technical field.

Background technology

Monitoring newborn baby local organization blood fortune situation is observed its time dependent rule, for the sick process monitoring of giving of the baby who suffers from the Hypoxia and ischemia encephalopathic, result of treatment evaluation important definition is arranged.

Determine local organization oxygen metabolism situation, mainly contain based on the direct measuring method that wound PtO2 is arranged of electrochemical principle with based on the lossless detection method of optical measurement.And optical means can be finished noninvasive monitoring, and safety easy to use is reliable and stable.The invention belongs to a kind of in the optical means.The method of describing in the file of publication number CN 1365649A is based on the Lambert-Beer law of classics, this classical law is the situation at no scattering, for human body with strong scattering optical characteristics and other biological tissue, this law could use after must revising in such cases.On principle, directly under strong scattering, use classical Lambert-Beer law and can't obtain any correct result.Compare with CN1331953A with publication number US005632273A, CN1333011A, the present invention and its difference are: (1) the present invention detects " the blood oxygen parameter " of organizing blood oxygen saturation rather than general reference really.(2) the present invention utilizes the method for multiple light courcess and multi-detector to be different from the method for single light source and multi-detector, and our method is to improve the sensitivity and the signal to noise ratio (S/N ratio) of detection.(3) the present invention has provided semiempirical formula.(4) inhaling in short-term under the pure oxygen, obtaining local brain tissue blood oxygen saturation and running parameter.Fig. 1 gives the detection synoptic diagram of the method that has, and wherein a is a light source, and b is a detecting device, and c is probe, and d is a detecting device, and e is a deep layer tissue to be measured, and f is an outer tissue.

Summary of the invention

The object of the present invention is to provide a kind of oxygen uptake to stimulate the detection method of newborn baby local organization oxygen saturation down.

Monitoring newborn baby local organization blood fortune situation is observed its time dependent rule, suffers from the baby's of Hypoxia and ischemia encephalopathic therapeutic process monitoring, result of treatment and evaluates significant.From implementation method, although utilize the something in common of many measuring technologies in this field of absorption spectrum of oxyhemoglobin and reduced hemoglobin, but present patent application is compared its characteristics and superior being with in the past method and present domestic disclosed patented technology: the first, and when measuring tissue oxygenation saturation, its adopt a plurality of light sources to improve detection sensitivity.Second is different with other patents, can detect newborn baby local saturation and variation tendency thereof under oxygen uptake in short-term, provide a reaction normal newborn and an actual parameter suffering from neonate's brain oxygenation status of hypoxie-ischemic encephalopathy.These all are different from the scheme that is proposed in the patent that has now both at home and abroad.

1 is to be the optical sensor OPSU1 of r1 with light source LS1, LS2 distance in Fig. 2, the 2nd, with light source LS1, LS2 distance be the optical sensor OPUS2 of r2, the 3rd, with light source LS1, LS2 distance be the optical sensor OPUS3 of r3, the 4th, light source LS1, LS2,5 are the 1st layer tissue and represent with T1,6 are the 2nd layer tissue and represent that with T2 7 are the 3rd layer tissue and represent with T3, in the organize models that newborn baby blood oxygen is measured, T1 is a skin, T2 is skull and cerebrospinal fluid, and T3 is brain tissue (grey matter and a white matter).B1, b2, b3 are the track of photon transport.Detect the tissue of different depth, optical sensor OPUS is placed on the different distance with LS, what OPUS3 detected mainly is the information of T1 layer, and what OPUS2 detected is the information of T1 and T2 layer, and what OPUS1 detected mainly is the information of T1, T2 layer and T3 layer.Light source OPUS1, OPUS2, OPUS3 are r to the distance of LS ₁, r ₂, r ₃

The invention is characterized in that it contains following each step successively:

(1) on equally spaced each other three positions, biological tissue to be measured surface, respectively lays a photoelectric receiving tube OPUS.Extended line one end at above-mentioned three photoelectric receiving tube lines, lay the light source that two LEDs of a usefulness are formed, the centre distance of two adjacent photoelectric receiving tubes is between 2mm～10mm, the centre distance of all photoelectric receiving tubes and light source is between 20mm～50mm, in light source, a light emitting diode sends ruddiness, and another sends near infrared light.

(2) in not oxygen uptake of neonate and when being in rest state, detect each photoelectric receiving tube according to the following steps and receive same scattered light intensity, and calculate its optical density value OD according to this.

(2.1) under microprocessor controls, drive red light-emitting diode LED1 and send wavelength X ₁Light, in 0.5 millisecond, measure the value of scattered light intensity correspondence successively with three photoelectric receiving tube OPUS1～OPUS3; Under microprocessor controls, drive near infrared light LED 2 and send wavelength X again ₂Light, measure the value of scattered light intensity correspondence successively with three photoelectric receiving tube OPUS1～OPUS3;

(2.2) utilize optical density to calculate formula and calculate different the detection apart from down corresponding to the optical density value OD of different optical wavelengths by microcontroller _k ^{λ i}:

${\mathrm{OD}}_k^{{\mathrm{\λ}}_i}=\log \frac{I_o}{I_{\mathrm{kr}}},$

Wherein, k=1,2,3, represent three photoelectric receiving tubes from left to right respectively,

λ ⁱ=1,2, i=1,2, represent optical wavelength λ respectively ₁, λ ₂,

I _OiBe the light intensity of LED 1 or LED2 outgoing, I ₀₁, I ₀₂Represent optical wavelength λ respectively ₁, λ ₂Light send I _KrBe the reflective light intensity after the detected process of the photoelectric receiving tube OPUS biological tissue to be measured scattering-in that places diverse location;

(3) OD that measures according to step (2) _k ^{λ i}Value is calculated partial groups with oxygen saturation rSO by following step ₂, show and keeping records:

Earlier under the same oxygen condition, but the different optical density value that detects under the distance subtracts each other, and gets

$\mathrm{\ΔO}{D}_2^{{\mathrm{\λ}}_i}={\mathrm{OD}}_2^{{\mathrm{\λ}}_i}-{\mathrm{OD}}_1^{{\mathrm{\λ}}_i},$

$\mathrm{\Δ}{\mathrm{OD}}_1^{{\mathrm{\λ}}_i}={\mathrm{OD}}_3^{{\mathrm{\λ}}_i}-{\mathrm{OD}}_2^{{\mathrm{\λ}}_i},$

Calculate rSO by following experimental formula again ₂:

$\mathrm{rS}{O}_2=C{\left(\frac{\mathrm{\ΔO}{D}_1^{{\mathrm{\λ}}_1}}{{\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_2}}\right)}^2+B_1\left(\frac{{\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_1}}{\mathrm{\ΔO}{D}_1^{{\mathrm{\λ}}_2}}\right)+B_2\left(\frac{\mathrm{\Δ}{\mathrm{OD}}_2^{{\mathrm{\λ}}_1}}{\mathrm{\ΔO}{D}_2^{{\mathrm{\λ}}_2}}\right)+A,$

Wherein, the C value is 0.16～0.25,

B ₁Value is-1.66～-2.5,

B ₂Value is-0.13～-0.25,

The A value is 1.8～2.7;

(4) allow neonate's oxygen uptake a period of time, measure, calculate and record rSO with said method again ₂

(5) stop oxygen supply after oxygen uptake a period of time, measure, calculate and note down rSO through a period of time with above-described method again ₂, stop measuring.

Evidence: it can obviously detect normal youngster and infant at the notable difference of tissue oxygenation saturation, shows its change procedure, and local detection is highly sensitive.

Description of drawings

Fig. 1. existing detection method synoptic diagram.

Fig. 2. detection method synoptic diagram of the present invention.

Fig. 3. the haemoglobin absorption spectrum that the present invention obtains.

Fig. 4. the program flow diagram of the method for the invention.

Fig. 5. press the schematic appearance of the pick-up unit of the present invention's design.

Fig. 6. by the schematic block circuit diagram of designed system of the present invention.

Fig. 7. the rSO of normal newborn and infant ₂Curve map.

Embodiment

Inhaling in short-term under the pure oxygen condition, detecting and organize the parametric technique of blood oxygen saturation and its variation to contain following steps successively.

1. be ready to oxygen mask or oxygen ventilation pipe, the neonate is in rest state, and the basic value when writing down its not oxygen uptake detects each distance last OD value and record.

2. the 1. middle result who tests of foundation calculates local organization oxygen saturation rSO ₂, show and saving result.

3. with oxygen mask or directly allow neonate's oxygen uptake 60 seconds with the oxygen ventilation pipe with the 2L/min flow, record also shows rSO ₂

4. oxygen uptake after 60 seconds is removed oxygen mask or oxygen ventilation pipe, and record 120 is second local organization oxygen saturation rSO ₂, data are preserved the back and are finished test.

The described suction in short-term under the pure oxygen condition, the step that detects the parameter organize blood oxygen saturation and its variance values are contained following steps in 1. successively

The step of described Non-Destructive Testing blood oxygen contains following steps in 1. successively

1) photoelectric detector OPUS1, OPUS2, OPUS3 are placed and go up in position.

2) the 1st wavelength that drives among LS1 and the LS2 under microprocessor controls is luminous, and measures the value of scattered light intensity correspondence with OPUS1-OPUS3 according to sequential; The 2nd wavelength that drives among LS1 and the LS2 under microprocessor controls is luminous, and measures the value (see figure 2) of scattered light intensity correspondence with OPUS1-OPUS3 according to sequential.

3) utilize the formula of optical density to calculate the different optical density OD that detect under the distance _k

${\mathrm{OD}}_k=\log \frac{I_0}{I_{\mathrm{kr}}}----\left(1\right)$

K=1, the footnote of the different photoelectric detectors of 2,3 expressions, I _KrDetect through the reflective light intensity after the organization internal scattering for placing in the photoelectric detector OPUS of diverse location.I ₀Light intensity during for light source (LS1 among Fig. 2 and LS2) outgoing.

The step of described Non-Destructive Testing blood oxygen can be calculated the local organization oxygen saturation in 2., will contain following steps.

In order to calculate the local organization oxygen saturation, with (less than 0.5ms), approximate same blood oxygen condition in the approaching time interval down but r respectively the optical density expression formula under the different distance situation subtract each other, so obtain:

$\mathrm{\Δ}{\mathrm{OD}}_2^{{\mathrm{\λ}}_j}={\mathrm{OD}}_2^{{\mathrm{\λ}}_j}-{\mathrm{OD}}_1^{{\mathrm{\λ}}_j}$

${\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_j}={\mathrm{OD}}_3^{{\mathrm{\λ}}_j}-{\mathrm{OD}}_2^{{\mathrm{\λ}}_j}---\left(2\right)$

J=1,2 expression wavelength 1 and 2

Use rSO here, ₂Expression local organization oxygen saturation with difference and arterial oxygen saturation, and is represented with experimental formula (3).

$r{\mathrm{SO}}_2=C{\left(\frac{{\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_1}}{{\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_2}}\right)}^2+B_1\left(\frac{{\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_1}}{{\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_2}}\right)+B_2\left(\frac{{\mathrm{\ΔOD}}_2^{{\mathrm{\λ}}_1}}{{\mathrm{\ΔOD}}_2^{{\mathrm{\λ}}_2}}\right)+A---\left(3\right)$

The C value is between 0.16 ~ 0.25, and the B1 value is between-1.66 ~-2.5, and the B2 value is between-0.13 ~-0.25, and the A value is between 1.8 ~ 2.7.

Constitute by sensor, preamplifier circuit, A/D converter, embedded microcontroller, external SRAM, LCD by designed system of the present invention, as shown in Figure 6.

The typical hardware unit that goes out according to the diffused light principle design, as shown in Figure 6.Light source LS (becomes a line) with 3 OPUS with 2 LED (each LED has two wavelength) on different distances, detect light intensity by OPUS and change, and OPUS adopts 2CU30S.OPUS is connected to prime amplifier TLC27L4, and the LF398 work of microcontroller AT89C52 control sampling holder also starts A/D TLC2543 conversion, and transformation result is read and write down sampled value.LS is luminous for the microcontroller driving light source, and will be saved in storage chip 6264 by the A/D conversion value of OPUS detected value, and above-mentioned advantage: the consistance of passage is fine, makes data that comparability be arranged.

There are 2 LED to be used for improving signal to noise ratio (S/N ratio), r in the probe among the present invention in the device ₂, r ₃2 influences that OPUS is used to proofread and correct outer tissue at place.In whole tissue, owing to certain feature that is absorbed with of biological tissue, have only the selection suitable wavelengths, could calculate local organization oxygen saturation and blood oxygen concentration preferably and change.The measurement medium wavelength of different tissues is selected some difference, the 780nm/840nm when brain tissue detects, so we have adopted the component leds of 780nm/840nm.For biological tissue is not produced any injury, the luminous power of LED should be less than 10mW.

Introduction by above-mentioned hardware configuration and principle of work, the system signal flow process can reduce: (1) microcontroller sends control signal to the LS driver element, LED luminous (2) light is connected to prime amplifier (4) 3 road sampling holders signal sampling is kept from detection position outgoing (3) OPUS1, OPUS2, OPUS3 detection light intensity through tissue (5T1 among Fig. 1,6T2,7T3), A/D converter is changed, and by microprocessor controls transformation result is read in SRAM and preserves.(5) by calculating in the microcontroller and demonstration local organization oxygen saturation rSO2.

In microcontroller, calculate the OD value on 3 distances, utilize formula, calculate rSO2.

Experiment effect

Utilize the present invention to test baby's oxygen uptake process under rest state of normal infant and trouble encephalopathic, tissue oxygenation saturation and change procedure as shown in Figure 7, are checked normal and infant significant difference (P＜0.005) through Aspin-Welch.

The effect of bringing after the invention process can reduce: (1) is owing to adopt two light sources that detection sensitivity, signal to noise ratio (S/N ratio) are improved, make tissue oxygenation saturation parameter detecting reliable and stable (2) under oxygen uptake in short-term, can detect newborn baby local saturation and variance values thereof, provide a reaction normal newborn and an actual parameter suffering from neonate's brain oxygenation status of hypoxie-ischemic encephalopathy, in time reflect newborn baby local circulation situation.

Claims (1)

1. oxygen uptake stimulates the detection method of newborn baby local organization oxygen saturation down, contains the detection step of near infrared biological tissue blood oxygen parameter, it is characterized in that it contains following each step successively:

(1) on equally spaced each other three positions, biological tissue to be measured surface, respectively lays a photoelectric receiving tube OPUS.Extended line one end at above-mentioned three photoelectric receiving tube lines, lay the light source that two LEDs of a usefulness are formed, the centre distance of two adjacent photoelectric receiving tubes is between 2mm～10mm, the centre distance of all photoelectric receiving tubes and light source is between 20mm～50mm, in light source, a light emitting diode sends ruddiness, and another sends near infrared light.

(2) in not oxygen uptake of neonate and when being in rest state, detect each photoelectric receiving tube according to the following steps and receive same scattered light intensity, and calculate its optical density value OD according to this.

(2.1) under microprocessor controls, drive red light-emitting diode LED1 and send wavelength X ₁Light, in 0.5 millisecond, measure the value of scattered light intensity correspondence successively with three photoelectric receiving tube OPUS1～OPUS3; Under microprocessor controls, drive near infrared light LED 2 and send wavelength X again ₂Light, measure the value of scattered light intensity correspondence successively with three photoelectric receiving tube OPUS1～OPUS3;

(2.2) utilize optical density to calculate formula and calculate different the detection apart from down corresponding to the optical density value OD of different optical wavelengths by microcontroller _k ^{λ i}:

${\mathrm{OD}}_k^{{\mathrm{\λ}}_i}=\log \frac{I_o}{I_{\mathrm{kr}}},$

Wherein, k=1,2,3, represent three photoelectric receiving tubes from left to right respectively,

λ ⁱ=1,2, i=1,2, represent optical wavelength λ respectively ₁, λ ₂,

I _OiBe the light intensity of LED 1 or LED2 outgoing, I ₀₁, I ₀₂Represent optical wavelength λ respectively ₁, λ ₂Light send I _KrBe the reflective light intensity after the detected process of the photoelectric receiving tube OPUS biological tissue to be measured scattering-in that places diverse location;

(3) OD that measures according to step (2) _k ^{λ i}Value is calculated partial groups with oxygen saturation rSO by following step ₂, show and keeping records:

Earlier under the same oxygen condition, but the different optical density value that detects under the distance subtracts each other, and gets

${\mathrm{OD}}_2^{{\mathrm{\λ}}_i}=O{D}_2^{{\mathrm{\λ}}_i}-{\mathrm{OD}}_1^{{\mathrm{\λ}}_i},$

$\mathrm{\Δ}{\mathrm{OD}}_1^{{\mathrm{\λ}}_i}=O{D}_3^{{\mathrm{\λ}}_i}-{\mathrm{OD}}_2^{{\mathrm{\λ}}_i},$

Calculate rSO by following experimental formula again ₂:

${\mathrm{sSO}}_2=C{\left(\frac{\mathrm{\ΔO}{D}_1^{{\mathrm{\λ}}_1}}{{\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_2}}\right)}^2+B_1\left(\frac{{\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_1}}{{\mathrm{\ΔOD}}_1^{{\mathrm{\λ}}_2}}\right)+B_2\left(\frac{\mathrm{\Δ}{\mathrm{OD}}_2^{{\mathrm{\λ}}_1}}{\mathrm{\Δ}{\mathrm{OD}}_2^{{\mathrm{\λ}}_2}}\right)+A,$

Wherein, the C value is 0.16～0.25,

B ₁Value is-1.66～-2.5,

B ₂Value is-0.13～-0.25,

The A value is 1.8～2.7;

(4) allow neonate's oxygen uptake a period of time, measure, calculate and record rSO with said method again ₂

(5) stop oxygen supply after oxygen uptake a period of time, measure, calculate and note down rSO through a period of time with above-described method again ₂, stop measuring.

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