RU2001595C1 - Device for determining degree of hyperbilirubinemia - Google Patents

Description

light carrying information about the internal subcutaneous tissue, which improves the accuracy of determining the content of bilirubin.

The disadvantages of the known device are the low accuracy of the measurements, which does not meet the current medical requirements of total screening, and the increased energy consumption. This is related to that. that the signal processing in the known device is based on using the exponential time dependence of the decay in the intensity of the light pulse, flowing as the length of the interval between the times the converted signals reach the preset level is proportional to the bilirubin concentration only under the condition that the decay of the light radiation is exponential with high accuracy.

However, in real pulsed light sources (Lalm flashes), the characteristic of the attenuation of the intensity is close to exponential only in a small portion of the entire time interval of the luminescence, which leads in the known device to significant unproductive energy costs, significantly reducing the battery life of a portable screening device powered from built-in batteries or rechargeable batteries.

In addition, the temporal dependence of the light emission intensity of flash lamps changes during operation due to ablation of the glass bulb, atomization of the cathode material, etc., which leads to a change in the readings of the device when examining the same object, i.e. e. to reduce the accuracy of measurements.

The measurement accuracy is also reduced due to the fact that, as a rule, a pump flash is present in the emission spectrum. shortwave (A 410 nm) component. which excites fluorescence in the volume of biological tissues, which changes the spectral characteristics of the reflected radiation and. therefore, distorting information about the content of bilirubin.

The present invention is aimed at improving the accuracy of measuring the bilirubin content and reducing the energy consumption of the device.

The indicated result is achieved by that. that in a known device containing a pulsed light source coupled to an automatic excitation system, a transmission fiber, the input of which is optically coupled to a light source, a receiving fiber, a photoelectric conversion unit, the input of which is optically coupled to the output of the receiving fiber, and a signal processing unit , a subtraction circuit and two integrating amplifiers are introduced.

connected respectively between the outputs of the photoelectric conversion unit and the inputs of the subtraction circuit, the output of which is connected to the input of the signal processing unit, including in series

connected comparator and pulse width to code converter.

The features of the invention are also the following:

each of the integrating amplifiers

made on the basis of an operational amplifier, the non-inverting input of which is connected to a common bus, and the inverting input is connected to the output through a parallel-connected resistor and capacitance:

the parameters of the elements of integrating amplifiers satisfy the relation

"RCHM C

-Sim.

where is r3en. Cje and RCMM, Diet - the values of the resistors and capacitances of the integrating amplifiers corresponding to the green and blue output signals of the photoelectric conversion unit.

The comparator is made in the form of an operational amplifier, the inverting input of which to eliminate signal processing errors associated with a zero level drift of the signal at the input of the comparator is connected to the output through a frequency-dependent feedback circuit:

a transmitting light guide to exclude the short-wavelength component from the emission spectrum of the light source is made of material. absorbing light radiation with wavelengths less than 410 nm and transparent to visible light with wavelengths greater than 410 nm;

automatic excitation system

comprises a voltage converter connected by the outputs to the light source power supply unit and an energy storage device, a control circuit connected to a control input of the voltage converter, a start key connected to an input of the control circuit, the second input of which is connected to the output of the light source power supply:

the receiving and transmitting optical fibers by means of a fixing element are rigidly fastened to the light guide block, while the output end of the transmitting and input end of the receiving optical fibers are located in the same plane at a predetermined distance from each other to separate the volumetric light from the reflected light bearing information about the content bilirubin, from the smponemt associated with surface reflection, on the light guide block, made with the possibility of movement relative to the housing of the device, a permanent magnet is fixed as starts of the key of the automatic excitation system, a magnetically controlled switch with sealed contacts is used, mounted on the device body with the ability to operate under the action of the magnetic field of the permanent magnet with a certain movement of the light guide side relative to the case,

a holder with guide slots parallel to the axis of longitudinal movement of the light guide and the limiter L o; with a hole, the axis of which is parallel to o and longitudinal displacement, "of one unit, as well as a rod rigidly attached to its inner end with one end, are inserted into the device a light-guide block, while restricting it to another one, let us take a rod of at least two different minions, diameter., ty i, vetosdp01l BL iiij,) HOH n-equal guide and eat axle; end in the guides of the swarm, and dpo-Kc b - n. associated with L, start L jb.c i my city, kg

bci fs. i nv dsta & ng mi sgr / k / rnach s o

VC pOUCinj. Hrl FIG

time diagrams vi m L s and g - apt. I d V and r 3 example i; Nkrz, HOI ii vyuln 1i elektri (Tg oi.

C and .LOUSTIS Hd phi1 4 J ONE OF Pr) T iH1 / B bbiPO., H J-il-H Cn | Iche, (. KOI KuTiriOHOfiKH

 fioiictna Hd Fig. 4 b. One of Vfis Chyun tenn.

The output of the pulsed light source is 1–1 (Fig. 11 connected with the system

2cib iOMSTHHi excitation I transmit the udin and the receiving ceei output 3, 4 Lok 5 photogapic HZ formations ingiriruyuschie amplifiers 8 9 connected between the outputs of the block 5 of the photoelectric conversion and the inputs of the circuit 10, the output of which is connected to the input

R.OKY 11 of the JTOB blue processing, containing a camera 12 and a pulse width converter 13 to the photoelectric conversion code block 5, contains filters 6162 corresponding to the blue and green1 spectral regions, photoelectric converters 71.72

Integrating amplifiers 8 Oe are performed in the form of operational amplifiers with

the inverse of napjii / Gn, - the fifth connection of the capacitance C and the resistor R (Fig. 3) The parameters of the elements of the integrating amplifiers satisfy the relation

Rae i RCHH Est.

Kg mparator 12 REDUCED woofer in the operational amplifier with a frequency-dependent feedback circuit eliminating the influence of drift of zero input S11 input voltage (NALS)

The transmitting light guide 3 can be made, for example, of TF-11 GOSG3514-7b quartz glass, which attenuates the short-wavelength part from acheng.

System 2 of automatic excitation contains a conversion of 14 ntp connected to L iui 15 mg

source of sveg and ml of PRLOM 16 energy

Scheme 17 vripaunemn pr

To the first input of which the key switch N P P OVSSH

key 18 to the second, (code Lпок 15 power supply SSRTL

PreobraJOB3TOJ1K P d / tte / m

heart rate n code contains. connected generator 19 reel 20, d oshfra ir 21 and indie - U 2) (in.nn m cha, 1no. 1 installation and copoui t tkh 20 no t,) nr I ng shown)

PrioPrzogjreni. M n w w zsnch spu

W F D 14 Pr Of) pa3Uh | IDN fLMO CONSTANT AND TI RED 1 W rg i I .CMO C power supply. 1 (ilaicij with il1 akkum, lchgor and i tjnr Znnp)) high

For example, "ZhRNI (. L MLiVCf Т DliTI. I 1НнЦ Л | 1ЭЛ (I H4HL 2 j

TJMOK IS PingPG hl, Ж111 days r) ki muls roanich .iri.ci om 1c (the game about prem pifioni npoof f nov.11 11 and gp. Next 1st bncfr iO pozhen.1 i loi "change and bit to ((and pulse emit c) 1 light and msch be l.

Us etol 16 energy serves to

4th

deer) g, ergroG, tnsggi1 at the time

p.iGoTt npeobpaoUBci .hp 1 1 and subsequent JTOH energy i r4i elmsem | C 9, 11 Nt) -from 16 moss ib would be made in type 1 capacitor

0Start key

on the basis of a magnetically controlled switch with |

f Generator 19 can be performed according to scheme 2, as a counter 20 d chchfra5 torora 21 and indicator 22 are used standard chip microcircuits 564

The mechanical part of the device includes a housing 23, a fixing element 24, fastening the optical fibers 3 4, a permanent magnet 25, the holder 26 and REMOTE 27,

fixed on the housing 23, the rod 28. the return spring 29, the swing axis 30 of the light guide block made in the form of an equal-arm swing. The key switch 18 is mounted on the housing 23 in such a way that, with a certain longitudinal displacement of the optical fibers 3, 4 relative to the housing 23, the magnet 25 is near the magnetically controlled contacts of the key 18, which leads to their closure.

The device operates as follows.

A light pulse from a pulsed light source 1, excited by an automatic excitation system 2, is applied to a portion of the skin surface using a transmitting light guide 3. The irradiating pulse of light containing blue and green components in its spectrum, after reflection, scattering and absorption in the epidermal and true skin tissues, reaches subcutaneous fat, which in newborns contains a large amount of bilirubin (the content of bilirubin in the subcutaneous fatty tissue of due to its content in the blood). Due to the increased bilirubin content in the subcutaneous fat, effective absorption of short-wave, i.e. the blue component of the light pulse. Reflecting on subcutaneous tissue, a spectrally transformed light pulse again passes through the skin tissue, additionally being scattered and absorbed in it.

The reflected radiation, which carries information about the bilirubin content in the subcutaneous fat, is supplied by the receiving optical fiber 4 to the photoelectric conversion unit 5. In the photovoltaic conversion unit 5, the blue and green components are extracted (e.g., using interference filters 6.1, 6.2) and converted into electrical signals using photo converters 7.1, 7.2 (e.g., photodiodes).

Electric signals (blue and green, respectively) are integrated during the action of the light pulse by the integration amplifiers 8. 9. After the end of the light pulse, the integrators 8, 9 are discharged (Fig. 2, a), the output signals of the integrators are subtracted in the subtraction circuit 10, difference the signal (Fig. 2. b) enters the processing unit 11, where the time interval during which the difference signal is positive is determined using the comparator 12 and the pulse width converter 13 to the code

We show that the duration of this time interval is unambiguously related to the bilirubin content in subcutaneous fat.

5Signals from the output of photovoltaic conversion unit 5 charge during the entire duration of the light pulse of the flash lamp of the capacitance of the integration amplifiers 8.9 to some

0 final stresses proportional to the energy of light radiation at the wavelengths DSin. Aze L. At the end of the action of the light pulse, the capacitances begin to discharge through the resistors, at

5 this value of capacitance and resistors RCMH. Nzel. Ssin, Seel selected so. so that the discharge of capacitances occurs over times many times greater than the duration of the light pulse to. Time attenuation

The 0 signals at the outputs of the integrating amplifiers 8, 9 are described by an exact exponential dependence, with the parameters P3el. Counted. ROIM Sines determining the decay time constants are chosen as follows. to satisfy the relation

Raen Szel "RCHH Diet (e.g. 10

Ree Szel Yasin-Ssin). Mathematically, the decay in time of VCHH signals, the Node is described as follows: 0

VCHH - VOCHH-exp (Mo) Lsin, (1)

V3Pn Voiefl exp (t-to) / t3en. (2)

Where 1sim RCHH Ssin. T.Zel Rsen Sze to

5 moment of the end of the light pulse: a VOCHH, / ozel, taking into account the fulfillment of the Buger-Lamberg-Baer law in skin and subcutaneous biological tissues, are determined by the formulas

0VOCHH Asin 1xin Rhine-exp {-Xin X

x Cb-Oy. (3)

Vosen Azel Mosel F-Chel exp -Kzel X

x b - 0. (4)

5 where VOCHH, Vosen respectively the voltage values on the capacitive integrating amplifiers at the end of the light pulse at time t0;

Asin. Azel are the coefficients of photoelectric conversion at the wavelengths of Yasin and Azep, respectively:

(aspen, 1ozel spectral intensity of light incident on the skin, respectively, at the wavelengths Asin and A3el:

5 RSin, Rev - spectral factors of attenuation of light intensity due to its absorption, scattering and reflection by skin and subcutaneous biological tissues at Asin and Aien wavelengths, respectively.

Kb jmi, Kzel — spectral coefficients of light absorption by bilirubin, respectively. On WAVE LENGTHS Yasin and zel;

Cb is the concentration (density) of bilirubin in the subcutaneous tissue;

O, is the equivalent length of the optical absorption of light by bilirubin in the subcutaneous tissues.

If the photoelectric conversion coefficients ASIN and A3el are selected as follows. to fulfill equality

ASIN Azel Ozel Real- (5)

then from formulas (3). (4) follows

n (/ aspen / / ozel) (Ksii - - Kzel) Cb Ob.

(6)

those. the concentration of bilirubin Cb is proportional to the logarithm of the ratio of stresses on the capacitors of the integrators at the end of the light pulse

Cb Const ln (Vocn4 / Vo3e ").

(7)

since (Ksin - Kzel) and Ob are fixed quantities. Thus, to determine the concentration of Cb, it is necessary to determine the value of the logarithm of the ratio

VOCHH AND / VOL.

To determine the value of the indicated logarithmic voltage signals from the outputs of the integrating amplifiers 8.9 first, the frequency is taken from the subtraction circuit 10, then from the output of the subtraction circuit 10 (Fig. 2, b), the voltage difference signal is supplied but the complector 12, by means of which impulse (figure 2, c), the duration of each is equal to the duration of the positive difference of the signals of the Node and USin. The duration t of the positive value of the difference signal will determine the desired logarithm value 1n (/ aspen / node). Indeed, at time t, the following relation holds according to formulas (1), (2)

VCHH V3en - VOCMH exp (1 Cho) Lsin - Wozel exp (t -to) / ben.

after conversion, we get

Wasin / Nozel exp (f-to) / t3en / exp (t - b) Asin,

Further, having carried out the logarithm of the left and right parts, taking into account the equality of ICHH 10 Chzel. as well as to t. we get

ln (V0cWVo3en) -9t7 10 Tze.

and since i and l have a fixed value, then

f Const ln (VocMM / Vf, .. en). (8)

5Taking into account formulas (7) and (8), we obtain the relation

Smiling const -t.

(9)

as required, i.e. the concentration of bilirubin Cb in the subcutaneous tissues is uniquely determined by the duration t of the positive difference of the difference signal of the initial stresses.

Consider the work of a specific implementation of the device (Fig.Z. 4). When you press the outer end of the light guide block, consisting of light guides 3.4 and a fixing element 24. to the patient’s skin

moving the light guide block relative to the housing 23 of the device. Upon reaching a predetermined pressing force, the movement reaches a predetermined value (a predetermined pressing force at a given

the amount of displacement is provided by the spring 29). At the same time, the magnet 25 is near the contacts of the start key 18 and causes them to close. The activation of the start key 18 initiates the operation of the circuit 17

control voltage converter 14. The control circuit 17 provides a signal enabling operation of the voltage converter 14. the voltage transformer 14 generates a voltage charging the light source power supply unit 15 and the energy storage 16. Simultaneously with the start of operation of the transducer 14, sound alarm sockets (not shown in FIG. 4) are turned on, generating sound

Cow signal for a given time. Until the end of the sound signal, the light guide block must remain pressed against the skin.

Uniform pressing of optical fibers 3, 4

to the skin is provided by the implementation of the light guide block in the form of an equal arms swing with a movable axis 30, which moves in the slots of the holder 26. Simultaneously with the longitudinal movement of the light guide

the block can rotate (swing) about the axis of swing 30, which ensures its uniform pressure against the skin, the amount of swing is limited by the movement of the rod 28 in the hole of the limiter 27. After the battery 15 is fully charged, it discharges to the flash lamp 1, as a result of which a light pulse is generated. The current pulse flowing from the power supply unit 15 through the flashlight 1. generates on the current sensor (resistor) included in the output circuit of the power supply unit 15, the voltage supplied to the second input of the control circuit 17, which inhibits the operation of the voltage converter 14. The drive 16, charged to a voltage corresponding to the supply voltage of the conversion and signal processing elements (elements 8. 9. 10, 12, 19. 20, 21, 22), provides power to these elements after turning off the converter 14 (power supply circuit Fig. 3 are not shown).

The light pulse passes through the transmitting light guide 3 and penetrates into the skin and subcutaneous biotissues, the reflected light through the light guide 4 enters sequentially located interference filters 6.1. 6.2 and photodiodes 7.1, 7.2 of the photovoltaic conversion unit 5. Electrical signals corresponding to the blue and green wavelengths are fed to the integrating amplifiers 8. 9. The signals from the outputs of which are fed to the subtraction circuit 10, made on the resistor, the difference signal is comparated by the comparator 12. At the output of which a pulse is generated, the duration of which is equal to the time during which the difference signal is positive. The duration of this pulse is converted into code by the converter 13 - the pulse from the output of the comparator 12 allows the generator 19 to generate pulses with a constant frequency, the number of these pulses is counted by the counter 20. and the code from the output of the counter 20 through the decoder 21 is fed to the liquid crystal indicator 22. measurement cycle ends.

Compared with 2, the described device has the following main advantages: integration of the signals after their photoelectric conversion during the entire time of the action of the light pulse allows the energy used to produce the light pulse to be reduced, and. therefore, reduce the power consumption of the device; the formation of the exponential shape of the signals due to the charge and the subsequent discharge of integrating amplifiers 8. 9 eliminates the influence of changes in the time dependence of the intensity of the radiation source 1 on the parameters of the processed signals and, therefore, improves the accuracy of the device, subtracting signals and processing the difference signal in one channel it also improves the accuracy of the device compared to 2. where two signal processing in two channels is used.

Other advantages of the device in particular cases of its implementation are:

elimination of the influence of zero-level drift of the signal (as a result of external electromagnetic interference, changes in the supply voltage, etc.) in the processing channel on the accuracy of the device by performing a comparator 12 with frequency-dependent feedback, eliminating the distortion of the measurement results of the fluorescence phenomenon in of the studied tissues due to the implementation of the transmitting fiber 3 from a material that absorbs the short-wavelength part of the radiation: reducing the power consumption of the device circuit due to the disconnection of the voltage converter 14 topics 2 auto-excitement after

generating a light pulse and using the energy storage device 16 charged during the operation of the voltage converter 14 to power the measurement circuit elements: increasing the reliability of the device by using a magnetically controlled switch with sealed contacts as a start key 18, which provides a large number of operations: increase reproducibility of measurements by eliminating the unevenness of the pressing of the optical fibers 3.4 to the skin of the patient, which is ensured by the performance of a mechanical part STI device.

(56) Dewitt D.P. Hannemann R.E., WlecheU.F .: Method for determining bilirubin concentration from skin reflectance. United States patent N; 4029085 June 14. 1977. U.S. CI .: 128/2 R. 128/2 G. lnt.CI.2: A 61 V 5/00.

Akio Yamanishi: Medical instrument for determining jaundice. United States patent Ne 4267844 May 19, 1981. U.S.CI.:128/633; 128/665. lnt.CI.3: A 61 85/00.

Marshak I.S. Pulsed light sources. M.-L.: Gosenergoizdat, 1963.

U.S. Patent No. 4,267,844, cl. A 61 B 5/00, 1905 1991.

152001595

Claims (8)

1. DEVICE FOR DEFINITION sixteen 10 fifteen DEGREES OF HYPERBILIRUBINEMIA, containing a pulsed light source connected to the automatic excitation system 5, a transmitting optical fiber whose input is optically connected to a light source, a receiving optical fiber, a photoelectric conversion unit, the input of which is optically connected to the output of the receiving optical fiber, a signal processing unit characterized in that a subtraction circuit and two integrating amplifiers are inserted in it, respectively connected between the outputs of the photoelectric conversion unit and the inputs of the subtraction circuit, the output to Torah connected to the input of the processing unit comprising a series-connected comparator and preob- verters 2n pulse width in the code. 2. The device according to claim 1. characterized in that each of the integrating amplifiers is made in the form of an operational amplifier, the non-inverting input of which 25 is connected to a common bus, and the inverting input, which is the input of the integrating amplifier, is connected to the output of the operational amplifier through a parallel connected resistor and capacitance. 3. The device according to claim 2, characterized in that the parameters of the integrating amplifiers satisfy the relation  NeL Sam "Sei Rom. where is Nev, Szm, RCHH. Diet - the values of the resistors and capacitances of the integrating amplifiers, corresponding to the green and blue output signals of the photovoltaic conversion unit. 4. The device according to claim 1, characterized in that the comparator is made in the form of an operational amplifier, the non-inverting input and output of which are input and output, respectively wavelength range with wavelengths greater than 410 nm. 6. The device according to claim 1, characterized in that the automatic excitation system comprises a voltage converter connected by outputs to a light source power supply unit and an energy storage device, a control circuit connected to a control input of the voltage converter, a start key connected to an input of the circuit control, the second input of which is connected to the output of the power supply unit of the light source. 7. The device according to claim 1, characterized in that the receiving and transmitting optical fibers are rigidly fastened to the light guide block by means of a fixing element, wherein the output end of the transmitting and input end faces of the receiving optical fibers are located in the same plane and are equally separated from each other, and in the light output block, made with the possibility of moving relative to the device case, a permanent magnet is fixed, and a magnetic switch with an inverting input is connected to the output via a frequency dependent feedback loop. 5. The device according to claim 1, characterized in that the transmitting optical fiber is made of a material that absorbs light radiation with wavelengths less than 410 nm and transmits light radiation with hermetically sealed contacts, which is mounted on the device’s body and can be activated by the magnetic field of a permanent magnet at a certain moving the light-emitting unit relative to the housing. 8. The device according to .7, characterized in that. that it contains a holder rigidly fastened to the body with guide slots parallel to the axis of longitudinal movement of the light-emitting unit, and a stopper with a hole, the axis of which is parallel to the axis of longitudinal movement of the light guide block, as well as a rod fixed at one end to the comparator, and 45 to the inner end light guide block, and thirty 35 40 fifty another is inserted into the limiter hole, the rod diameter being at least two times smaller than the hole diameter, and the light guide block is made in the form of an equal-armed swing, the swing axis of which is inserted into the guide slots of the de-clasp, and connected to the limiter by a return spring. sixteen 0 5 P 5 wavelength range with wavelengths greater than 410 nm. 6. The device according to claim 1, characterized in that the automatic excitation system comprises a voltage converter connected by outputs to a light source power supply unit and an energy storage device, a control circuit connected to a control input of the voltage converter, a start key connected to an input of the circuit control, the second input of which is connected to the output of the power supply unit of the light source. 7. The device according to claim 1, characterized in that the receiving and transmitting optical fibers are rigidly fastened to the light guide block by means of a fixing element, wherein the output end of the transmitting and input end faces of the receiving optical fibers are located in the same plane and are equally separated from each other, and in the light output block, made with the possibility of moving relative to the device case, a permanent magnet is fixed, and a magnetic switch with fifty another is inserted into the limiter hole, the rod diameter being at least two times smaller than the hole diameter, and the light guide block is made in the form of an equal-armed swing, the swing axis of which is inserted into the guide slots of the de-clasp, and connected to the limiter by a return spring. F I t I f & -J ± J I ABOUT v b)  it RT11 Bl Gel 7.2 fie. 4