CN101091651A - Device and method for detecting depth of anesthesia - Google Patents

Abstract

The present invention relates to an anelocator equipment. It includes the following several portions: light source provider for providing light pulse; first coupler connected with said light source provider for receiving light pulse and outputting it and receiving scattered light and outputting it; sensing optical fiber connected with said first coupler, the action of light pulse and sensing optical fiber can produce Raman scattering; second coupler connected with said first coupler for dividing the scattered light into anti-stokes light and stokes light according to the light-splitting ratio of 90:10; and detection analyzer connected with second coupler for making signal processing analysis and display.

Description

Depth of anesthesia checkout equipment and depth of anesthesia detection method

Technical field

The present invention relates to medical fields of measurement, relate in particular to a kind of checkout equipment and detection method that is used to survey depth of anesthesia.

Background technology

Must implement enough anesthesia when the patient undergos surgery with the Intensive Care Therapy treatment at present, to allow the patient slow down pressure.When the patient who has implemented general anesthesia is carried out the depth of anesthesia monitoring, generally adopt brain electricity monitoring technology or both associatings of auditory evoked potential and brain wave.To being in the patient of light dormancy state after the anesthesia, can measure indirectly the reaction of sound and sensation by observing clinical sign and patient, comprise the test of auditory evoked potential.But above-mentioned this method may can be waken the patient that can make a response up owing to stimulation, and this method is not suitable for the patient that those can not be made a response yet.Especially because the auditory evoked potential test relates to too much afferent pathway and nerve, be difficult to accomplish accurately with anti-interference.The system of the brain electricity monitoring technology of employing brain wave also exists considerable weak point (1) has very big dependency with anaesthetic, but relevant with environmental stimuli not obvious, can not reflect the moving reaction of body in the art; (2) for brand-new anesthetics, its accuracy still has query; (3) computational speed is slower, take longer, approximately about 60 seconds; (4) system complex, the cost height.More than two kinds of technology not only exist various shortcomings, and these two kinds of methods are only used in the monitoring of general anesthesia at present.

And in local anesthesia,, still continue to use the twinge method so far for judging depth of anesthesia.Rely on patient's pain to judge anesthesia dosage and anesthesia scope roughly, want the twinge many places just can judge sometimes, both increased patient's misery, must rely on patient's subjectivity to cooperate again, error is bigger.In addition, also have at present and a kind ofly judge the method for the local anesthesia degree of depth, promptly survey human body the reaction of galvanism is detected flesh pine degree by surveying flesh pine degree.This method belongs to bayonet point, can only survey very little scope at every turn, obtains body surface larger area depth of anesthesia value if desired and then must repeatedly measure, and has increased the complexity and the difficulty of operation.If patient's muscle insensitive to stimulating (as myasthenia gravis patient etc.) then can cause the error even the inefficacy of detection.Error to depth of anesthesia and scope judgement not only may cause the reduction of anaesthetic effect also may cause patient's shock, organ failure, disable even brain death.

Temperature is one of important evidence of depth of anesthesia detection.Medical experiment is the result show, thumbtip under 20 minutes epidural anesthesias after the anesthesia medication, and the skin temperature of non-blocking zone such as forearm descends 1.08 ℃ and 0.98 ℃ respectively before than medication, and umbilical part, the skin temperature rising of blocking zones such as toe place does not wait for 0.57～4.33 ℃.The detected temperatures customary way is that spot measurement or pointwise gradation are measured in clinical, the big and shortage real-time of workload.Therefore the optical fiber distributed temperature sensor-based system occurred, it can distribute to the temperature field effectively and monitor in real time.Monitor the variation relation of the shell temperature field at anesthesia position in real time, and, different patients' difference is anaesthetized the variations in temperature at position and set up complete data base, just the judgement depth of anesthesia of energy science in conjunction with clinical trial with the anesthesia medication.

The existing distributed optical fiber temperature transducer system was proposed by Britain Nan Pudun university in 1981 the earliest, nineteen eighty-three, Britain carried out the distributed optical fiber temperature sensor original reason experiment with the laser Raman spectrum effect of liquid-core optical fibre, Britain Hartog in 1985 under lab carry out the thermometric experiment of distributed optical fiber temperature sensor as light source with argon ion laser, the same year, Hartog and Parter use semiconductor laser as light source respectively independently, have developed the distributed optical fiber temperature sensor experimental provision.The eighties, Britain YORK company successfully developed DTS-1 according to the spontaneous raman scattering principle design, DTS-2 type distributed optical fiber temperature sensor, system source is the LASER Light Source of 904nm, detector silicon materials avalanche photo diode (APD), can finish measurement to 2km optical fiber with 12s, repeatability when spatial resolution is 7.5m (1 times of standard deviation) is 0.4 ℃.At the beginning of the nineties, York company has released a kind of follow-on distributed temperature measuring DTS-80ULR of system, and it uses a single-mode fiber in length during as 40km, and range resolution ratio is 2m, and temperature resolution is 2 ℃.Main corrective measure has been to use a kind of diode pumped solid state laser device (Diode-pumped solid-state laser) to come the light pulse higher to the optical fiber injecting power, that width is narrower.

But, existing fiber temperature sensor spatial resolution and temperature resolution are all lower, only be fit to be applied to the occasion not high to resolution requirement, as for example commercial measurement such as oil well of some commercial measurement occasion, also be not applied to the body surface temperature survey, more be not applied to the detection of human body local anesthesia's degree of depth.Promptly also do not judge at present the instrument of the local anesthesia degree of depth, the measurement that the technology of distributing optical fiber sensing is applied to the body surface temperature is not also arranged by temperature survey.To a plurality of pick off multimeterings of the general at present employing of measurement of body surface temperature, but this method spatial resolution is very low, cost height, low precision.

Summary of the invention

The objective of the invention is provides a kind of depth of anesthesia checkout equipment and detection method based on distributing optical fiber sensing in order to solve the problem that prior art exists, and realizes adopting the mode of measuring the body surface temperature field to carry out the real-time monitoring of quantitative depth of anesthesia.

To achieve these goals, local anesthesia depth detection equipment provided by the invention comprises: light source provides device, and the pass that light impulse length and spatial resolution are satisfied in output is: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse, v wherein _gBe the speed of light in optical fiber, t _wBe light impulse length;

First bonder provides device to be connected with described light source, is used to receive described light pulse and with its output and receiving scattered light and with its output, this scattered light power P _As=P α _AsSX (1-X) is α wherein _AsBe Raman (Raman) scattering coefficient, S is the backscattering factor and loss, and P is an input optical power, and x is the percentage ratio of input optical power and Output optical power;

Sensor fibre is connected with described first bonder, and described sensor fibre is imported in described light pulse, with described sensor fibre effect generation Raman scattering, by the 3rd outfan output scattered signal of first bonder;

Second bonder is connected with described first bonder, and being used for according to splitting ratio is scattered light to be divided into anti-Stokes light (anti-stokes) and stokes light (stokes) in 90: 10;

The check and analysis device is connected with described second bonder, is used to survey Stokes optical signal and anti-Stokes optical signal and carries out signal processing analysis and demonstration.

Preferably, described second bonder is connected by optical fiber filter with the check and analysis device.

Preferably, the number of described optical fiber filter is 2, and it is anti-Stokes light λ that one of them optical fiber filter adopts centre wavelength _AsFirst wave filter, and another optical fiber filter to adopt centre wavelength be stokes light λ _sSecond wave filter, described first wave filter is connected with the check and analysis device with described second bonder respectively with second wave filter.

Preferably, described first bonder comprises first input end, second end and the 3rd outfan, and described first input end provides device to be connected with described light source, and described first input end receives described light pulse; Described second end is connected with sensor fibre, output optical pulse, and described further sensor fibre and described light pulse generation Raman scattering, the output scattered light is given described second end; And described the 3rd outfan is connected with second bonder, exports described scattered light.

Preferably, described light source provides device to comprise:

The laser modulation circuit is used to modulate the pass of satisfying light impulse length and spatial resolution and is: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse, v wherein _gBe the speed of light in optical fiber, t _wBe light impulse length;

Laser instrument with described laser modulation circuit, is used to export the light pulse after the modulation.

Preferably, described laser modulation circuit comprises:

Drive circuit for laser is connected with described laser instrument, is used to drive described laser instrument output optical pulse;

Pulse-generating circuit is connected with described drive circuit for laser, is used for the pass that light pulse with laser instrument output is modulated into light impulse length and spatial resolution to be: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse;

Temperature feedback circuit is connected with laser drive circuit with described laser instrument, is used to survey the temperature of current lasers, laser temperature is adjusted in good time, guarantees that laser works is in stationary temperature.

Preferably, described check and analysis device comprises:

The PIN photodetector is connected with described wave filter, and being used for described Stokes optical signal and anti-Stokes light conversion of signals is two path signal;

The photoelectric current testing circuit is connected with described PIN photodetector, is used for the described signal of telecommunication of amplification filtering;

The antilogarithm computing circuit is connected with described photoelectric current testing circuit, is used for the conversion of signals after amplifying linear;

Voltage stabilizing circuit is connected with the antilogarithm computing circuit with described photoelectric current testing circuit, is used to provide voltage of voltage regulation;

Data collecting card is connected with described antilogarithm computing circuit, is used to gather the signal of telecommunication of handling through the antilogarithm computing circuit;

Processor with described data acquisition card connection, is used for two path signal is carried out the ratio computing, and the ratio that obtains according to computing carries out temperature computation, obtains the temperature field information of scattered light scattering position x,, repeat 2 ¹⁸Inferior ratio computing obtains 2 ¹⁸Individual temperature field information is with 2 ¹⁸Individual temperature field information adds up, and utilizes 16 sliding windows of 4 rank multinomials to carry out the distribution that the method for least square moving average obtains two-dimensional temperature field.

Preferably, described first bonder is connected by temperature chamber with sensor fibre, and described temperature chamber is used to provide constant temperature not to be subjected to the influence of ambient temperature to guarantee sensor fibre.

Preferably, described laser instrument is that power is 2w, and centre wavelength is 808.6nm, spectral width 1.6nm, and operating current is 1.5A.

Preferably, described sensor fibre is high germnium doped fiber, and it mixes germanium concentration is 10mol%.

Preferably, described photoelectric current testing circuit adopts logafier AD8304.

To achieve these goals, the present invention also provides a kind of depth of anesthesia detection method, and this method comprises:

The pass that light impulse length and spatial resolution are satisfied in output is: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse, v wherein _gBe the speed of light in optical fiber, t _wBe light impulse length;

Light pulse after overcoupling with sensor fibre effect generation Raman scattering, produce scattered light, this scattered light power P _As=P α _AsSX (1-X) is α wherein _AsBe the Raman scattering coefficient, S is the backscattering factor and loss, and P is the luminous power of input first input end, and X is the percentage ratio of the luminous power of first input end input optical power and the output of second end;

According to splitting ratio is scattered light to be divided into anti-Stokes light and stokes light in 90: 10 and to survey the Stokes optical signal and the anti-Stokes optical signal carries out signal processing analysis and shows.

The described signal processing analysis that carries out comprises: with described Stokes optical signal and anti-Stokes light conversion of signals is two path signal, and carry out filtering, and the two path signal that converts linear relationship to carried out the ratio computing, the ratio that obtains according to computing carries out temperature computation, obtain the temperature field information of scattered light scattering position x, repeat 2 ¹⁸Inferior ratio computing obtains 2 ¹⁸Individual temperature field information is with 2 ¹⁸Individual temperature field information adds up, and utilizes 16 sliding windows of 4 rank multinomials to carry out the distribution that the method for least square moving average obtains two-dimensional temperature field.

Alternatively, the described ratio R that obtains according to computing [T (x)] is carried out temperature T (x) and is calculated as: the exponential relationship of utilizing the anti-Stokes light of scattered light scattering position x and the ratio R of Stokes light intensity [T (x)] and temperature: $R\left[T\left(x\right)\right]=\frac{P_{\mathrm{as}}\left[T\left(x\right)\right]}{P_s\left[T\left(x\right)\right]}={\left(\frac{{\mathrm{\λ}}_s}{{\mathrm{\λ}}_{\mathrm{as}}}\right)}^4\·\exp [-\frac{T_0}{T\left(x\right)}]\·\exp \{-[\mathrm{\α}\left({\mathrm{\λ}}_{\mathrm{as}}\right)-\mathrm{\α}\left({\mathrm{\λ}}_s\right)]\·x\}$ Obtain temperature T (x); Wherein, λ _AsBe anti-Stokes optical wavelength and λ _sBe the Stokes optical wavelength, α (λ _As) the fibre loss coefficient that causes by Rayleigh scattering when anti-Stokes light light transmits in optical fiber, α (λ _s) fibre loss that causes by Rayleigh scattering when in optical fiber, transmitting for stokes light light; $T_0=\frac{\mathrm{hc\Δv}}{k_B}$ , h=planck constant, Δ v are Raman frequency shift, k=Boltzmann constant, c are the light velocity; T (x) is the temperature at position x; And x is some distance from the starting point of sensor fibre of sensor fibre.

Alternatively, the described ratio R that obtains according to computing [T (x)] is carried out temperature T (x) and is calculated as: utilize $\frac{1}{T\left(x\right)}=\frac{1}{T_1\left(x\right)}-\frac{1}{T_0}\·\ln \left(\frac{R\left[T\left(x\right)\right]}{R\left[T_1\left(x\right)\right]}\right)$ Obtain; R[T wherein ₁(x) be position x temperature T ₁The time anti-Stokes light that records and the ratio of stokes light; $T_0=\frac{\mathrm{hc\Δv}}{k_B}$ , h=planck constant, Δ v are Raman frequency shift, k=Boltzmann constant, c are the light velocity; T (x) is the temperature in the x position; And x is some distance from the starting point of sensor fibre of sensor fibre.

Therefore, detect shell temperature by sensor fibre of the present invention, utilize Raman scattering from variation of temperature monitoring human depth of anesthesia, adopt the checkout equipment and the detection method of the date processing that average summation and method of least square combine to realize measuring simultaneously multi-point temp, detected temperatures changes in real time, and can draw out the temperature profile at tested position on computers, and has high spatial resolution, response time is fast, and advantage of high precision.

Description of drawings

Fig. 1 is the structural representation of depth of anesthesia checkout equipment of the present invention;

Fig. 2 provides the structural representation of device for light source of the present invention;

Fig. 3 carries out optical coupling and sketch map along separate routes for the present invention's first bonder;

Fig. 4 is the structural representation of check and analysis device of the present invention.

The specific embodiment

As shown in Figure 1, be the structure chart of depth of anesthesia checkout equipment 1 of the present invention.This checkout equipment comprises:

Light source provides device 1, and the pass that light impulse length and spatial resolution are satisfied in output is: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse, v wherein _gBe the speed of light in optical fiber, t _wBe light impulse length;

First bonder 2 provides device 1 to be connected with described light source, is used to receive described light pulse and with its output and receiving scattered light and with its output, this scattered light power P _As=P α _AsSX (1-X) is α wherein _AsBe the Raman scattering coefficient, S is the backscattering factor and loss, and P is an input optical power, and X is the percentage ratio of input optical power and Output optical power;

Sensor fibre 3 is connected with described first bonder 2, and described sensor fibre is imported in described light pulse, with described sensor fibre effect generation Raman scattering, by first bonder output scattered signal; When measuring temperature field one regularly, improve system sensitivity, need to improve Raman frequency shift amount Δ v, and Δ v is only relevant with the material of sensor fibre; Therefore preferably sensor fibre 3 adopts high germnium doped fiber, and parameter is: mixing germanium concentration is 10mol%, and chromatic dispersion is 3.5ps/km.nm, and loss is 0.5dB/km;

Second bonder 4 is connected with described first bonder 2, and being used for according to splitting ratio is scattered light to be divided into anti-Stokes light and stokes light in 90: 10; Because anti-Stokes light ratio stokes light is weak a lot, limited luminous power is more given anti-Stokes light, can effectively dwindle the gap of anti-Si Tuosi light and Stokes luminous power, prevent that anti-Si Tuosi light and stokes light power ratio are too small, therefore the splitting ratio with second bonder 4 is chosen as 90: 10.

Check and analysis device 5 is connected with described second bonder 4, is used to survey Stokes optical signal and anti-Stokes optical signal and carries out signal processing analysis and demonstration.

The structural representation of device 1 wherein, is provided referring to light source of the present invention shown in Figure 2.This light source provides device 1 to comprise:

Laser modulation circuit 11 is used to modulate the pass of satisfying light impulse length and spatial resolution and is: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse, v wherein _gBe the speed of light in optical fiber, t _wBe light impulse length; And laser instrument 12, be connected with laser modulation circuit 11, be used to export the light pulse after the modulation.

In this example, satisfy the requirement that system space resolution is 1m, it is 10ns that the light pulse that laser instrument 102 is sent is modulated to pulsewidth.Because spontaneous Raman scattering intensity is very little, is about 10 of incident intensity ^-7, scattered light is detected, the incident illumination peak power is not less than 500mw.Therefore, preferably, laser parameter is: fiber power is 2w, and centre wavelength is 808.6nm, spectral width 1.6nm, operating current 1.5A.

Further, continue to provide referring to light source shown in Figure 2 the structural representation of device 1, laser modulation circuit 11 comprises:

Drive circuit for laser 110 is connected with described laser instrument 12, is used to drive described laser instrument output optical pulse;

Pulse-generating circuit 111 is connected with described drive circuit for laser 110, is used for the pass that light pulse with laser instrument output is modulated into light impulse length and spatial resolution to be: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse;

Temperature feedback circuit 112 is connected with laser drive circuit 110 with described laser instrument 12, is used to survey the temperature of current lasers, laser temperature is adjusted in good time, guarantees that laser works is in stationary temperature.

Referring to shown in Figure 1, be not subjected to the influence of ambient temperature for guaranteeing sensor fibre again, first bonder 2 is connected by temperature chamber 8 with sensor fibre 3, and described temperature chamber 8 is used to provide constant temperature.

Because scattering takes place in the light pulse of first bonder, 2 outputs and sensor fibre 3 effects, scattered light is except comprising needed Raman diffused light, also contain Rayleigh scattering light and Brillouin scattering, these two kinds of scattered lights will cause background noise when surveying, especially Rayleigh scattering light, its beam intensity ratio Raman diffused light exceeds 3～4 orders of magnitude.Because the wavelength of Rayleigh scattering light and Brillouin scattering is different with the Raman scattering light wavelength, therefore can use optical band pass filter that Raman diffused light is leached.Therefore as shown in Figure 1, second bonder 4 and check and analysis device 5 are connected by optical fiber filter.

Further, because anti-Stokes light and stokes light need to survey respectively, so use two centre wavelengths to be respectively anti-Stokes light λ _AsFirst wave filter 6 and stokes light λ _sSecond wave filter 7.The number of optical fiber filter is 2 as shown in Figure 1, and wherein first wave filter 6 is connected with check and analysis device 5 with second bonder 4 respectively with second wave filter 7.Because the central wavelength lambda of laser instrument ₀=808nm, Raman frequency shift are Δ v=440cm ^-1So anti-Stokes optical wavelength and Stokes optical wavelength are respectively 780nm and 838nm.Preferably, first wave filter 6 is an optical fiber filter, and centre wavelength is 780nm, and three dB bandwidth is 2nm, and the insertion loss is 0.3dB, minimum isolation 20dB.Preferably, second wave filter 7 is an optical fiber filter, and centre wavelength is 838nm, and three dB bandwidth is 2nm, and the insertion loss is 0.3dB, minimum isolation 20dB.

Further, as shown in Figure 3, first bonder 2 carries out optical coupling and sketch map along separate routes.First bonder 2 comprises first input end 21, second end 22 and the 3rd outfan 23, and first input end 21 provides device 1 to be connected with light source, and first input end 21 receives the light pulse of laser instrument output; Second end 22 is connected with sensor fibre, output optical pulse, and described further sensor fibre and described light pulse generation Raman scattering, the output scattered light is given described second end; And described the 3rd outfan is connected with second bonder, exports described scattered light.First input end 21 links to each other with laser instrument, is the input of light pulse; The 3rd outfan links to each other with second bonder, is the output of Raman rear orientation light; Second end links to each other with sensor fibre.Owing to will improve the temperature resolution of system, will improve the signal to noise ratio of system exactly.When reducing system noise, more to manage to improve the scattered light power that detector receives as far as possible.Under the situation of laser output power peak value less than the stimulated Raman scattering threshold value, when exporting, bonder reaches maximum for making rear orientation light, should correctly select the splitting ratio of bonder.If during the second end input optical signal, the percentage ratio that the first input end Output optical power accounts for total luminous power is X, when the first input end input optical signal, the percentage ratio of the luminous power of second end output also is X so.Suppose that the luminous power that enters the bonder first input end from laser instrument is P, and the Raman scattering coefficient is α _As, the backscattering factor and loss are S, then the scattered light power P of exporting from the 3rd outfan _As=P α _AsSx (1-X) for obtaining the maximum of scattered light power, asks the extreme value of quadratic polynomial, then when X=50%, and P _AsMaximum.So the best splitting ratio of first bonder is 1: 1.Therefore, in this example, first bonder is preferably Y type directional coupler, and concrete parameter is: splitting ratio is 50: 50, and the insertion loss is 3.0dB, and added losses are 0.03dB, and Polarization Dependent Loss is 0.1dB, operation wavelength 808nm, and bandwidth is ± 40nm.Selecting splitting ratio is after 50: 50, and scattered light reaches maximum from bonder output.

As the structural representation of Fig. 4 for check and analysis device 5 of the present invention.Because the spontaneous Raman scattering light intensity is very faint, than little 7～8 orders of magnitude of incident intensity, be 1w if inject luminous power, then the back is about several nanowatts to Raman diffused light.Therefore when photodetector is converted to the signal of telecommunication with optical signal, will introduce bigger noise, make the data that record depart from true value.Yet in Feebleness Light Signal Examining, show as the fluctuation and the burr of anti-Stokes optical signal.In order to reduce noise, to improve signal to noise ratio, need to use the Detection of Weak Signals technology.Therefore adopt the PIN photodetector in this check and analysis device, centre wavelength is 808nm, and the minimum detectable luminous power is-65dBm, and dark current is less than 1nA, and responsiveness is greater than 0.85A/W, and response time is 1ns, and the tail optical fiber connected mode is FC/PC.

Described check and analysis device 5 comprises: PIN photodetector 51, be connected with described optical fiber filter 6, and being used for described Stokes optical signal and anti-Stokes light conversion of signals is two path signal;

Photoelectric current testing circuit 52 is connected with described PIN photodetector 51, is used for the described signal of telecommunication of amplification filtering;

Antilogarithm computing circuit 53 is connected with described photoelectric current testing circuit 52, is used for the electrical signal conversion after amplifying linear;

Voltage stabilizing circuit 54 is connected with antilogarithm computing circuit 53 with described photoelectric current testing circuit 52, is used to provide voltage of voltage regulation;

Data collecting card 55 is connected with described antilogarithm computing circuit 53, is used to gather the signal of telecommunication of handling through the antilogarithm computing circuit;

Processor 56 is connected with described data collecting card 55, is used for two path signal is carried out the ratio computing, and the ratio that obtains according to computing carries out temperature computation, obtains the temperature field information of scattered light scattering position x, repeats 2 ¹⁸Inferior ratio computing obtains 2 ¹⁸Individual temperature field information is with 2 ¹⁸Individual temperature field information adds up, and utilizes 16 sliding windows of 4 rank multinomials to carry out the distribution that the method for least square moving average obtains two-dimensional temperature field.The ratio that obtains according to computing carries out temperature computation has two kinds of algorithms to be described in detail below.

In this example, above-mentioned (1) photoelectric current testing circuit adopts AD8304, and detectable 100pA～10mA, output voltage are 0.1～1.6V; (2) antilogarithm computing circuit adopts audion 9014; (3) data collecting card is PCI8344A, and sample frequency: 1CH carries out AD conversion, 4M/CH; Input resolution: 12Bit; (4) power supply stabilization circuit adopts the AD ADP3331 of company, and output voltage is 5V.Processor 56 adopts computers to carry out signal processing, even owing to only consider the noise that receiver is introduced, signal to noise ratio also will be less than 1, and signal is submerged in the noise fully.Therefore, signal be extracted from noise, and reach the desired temperature resolution of system in theory, preferably use method such as on average add up.And the raising of signal to noise ratio is to be directly proportional with the square root of accumulative frequency.Accumulative frequency is many more, and the signal that demodulation is come out is just more near actual value.Can obviously improve signal though increase accumulative frequency, noise can not be eliminated by adding up fully, therefore needs to adopt least square curve fit.Thus, computer adopts and adds up 2 ¹⁸Inferior, and adopt 16 sliding windows of 4 rank multinomials to carry out the method for least square moving average.

Introducing depth of anesthesia checkout equipment of the present invention below utilizes Raman scattering to detect the principle of depth of anesthesia: according to Theory of Electromagnetic Field, because the influence of factors such as the micro-variations of fiber core dielectric material density and composition fluctuating, incident photon and medium molecule interact, except the Rayleigh scattering of generation and incident illumination same frequency, because the nonlinear effect of medium, inelastic collision also takes place in incident photon and molecule.Between photon and the molecule energy exchange takes place in inelastic process, photon has not only changed travel direction, simultaneously portion of energy is passed to molecule, and perhaps the energy delivery of molecular vibration and rotation is given photon, thereby changes the frequency of photon.This process is called Raman scattering.When variations in temperature, Raman scattering intensity can change thereupon, the rear orientation light that produces by each point on the optical fiber when detection light pulse is transmitted in optical fiber, obtain along the information in the temperature field of fiber path according to the entrained temperature information of scattered light again, in conjunction with the relation and the corresponding clinical database of existing shell temperature and local depth of anesthesia, just can obtain the depth of anesthesia of detected part.

When using depth of anesthesia checkout equipment detection patient's of the present invention depth of anesthesia, sensor fibre is entangled in patient's body surface, drive circuit for laser produces the pulse that a series of pulsewidths are 10ns, modulated laser, and making the output optical pulse pulsewidth is 10ns.A light pulse enters sensor fibre after through first bonder, be subjected to the influence of human body temperature field after, Raman scattering takes place, produce the anti-Stokes light and the stokes light of varying strength at the diverse location of sensor fibre, and reflect.The light of diverse location reflection arrives the asynchronism(-nization) of PIN detector, just can the resolved light signal have reflected the temperature information of which position of optical fiber according to the difference of time.Anti-Stokes and stokes light power ratio have then reflected the temperature level of that position.Preestablish the position of each sensing point of sensor fibre, can determine its position by the following method.For example 1 place sets a temperature field in the position, and light pulse of laser instrument emission is sent light pulse from laser instrument and begun to count, and detects the time that receives scattered light, and 2us for example delays time.Utilize this method can be with the i.e. body surface position of actual required anesthesia, the position on the sensor fibre, also i.e. this scattered light scattering position, position x be mapped with corresponding time delay, position 1 corresponding time-delay 2us for example, position 2 corresponding time-delay 3us or the like.Like this, when actual detected, detect the time delay that receives certain reflected light signal, just can accurately judge according to the corresponding relation of previous time delay of measuring and position is the optical signal of which position again.

Scattered light enters second bonder, is divided into two-way, and wherein one the tunnel is to leach stokes light and enter the PIN detector behind the wave filter of 780nm to convert corresponding electric signal to through centre wavelength.Other one the tunnel is to leach anti-Stokes light behind the wave filter of 838nm through centre wavelength, and enters the PIN detector and convert corresponding electric signal to.This two path signal is entered PC by the data collecting card collection after the AD8304 amplification filtering respectively.

Based on depth of anesthesia checkout equipment provided by the invention, obtain along the information in the temperature field of fiber path according to the entrained temperature information of scattered light and to carry out the method that depth of anesthesia detects, mainly comprise: step 1, the pass that light impulse length and spatial resolution are satisfied in laser instrument output is: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse, v wherein _gBe the speed of light in optical fiber, t _wBe light impulse length;

Step 2, light pulse after overcoupling with sensor fibre effect generation Raman scattering, produce scattered light, this scattered light power P _As=P α _AsSX (1-X) is α wherein _AsBe the Raman scattering coefficient, S is the backscattering factor and loss, and P is an input optical power, and X is the percentage ratio of input optical power and Output optical power;

Step 3 is scattered light to be divided into anti-Stokes light and stokes light in 90: 10 according to splitting ratio;

Step 4 is surveyed Stokes optical signal and anti-Stokes optical signal and is carried out signal processing analysis and demonstration.In this example, suppose that detector is to send Stokes optical signal and the anti-Stokes optical signal of receiving behind the pulse 2us at laser instrument, has promptly obtained the Stokes optical signal and the anti-Stokes optical signal of position 1.

Wherein, carrying out signal processing analysis in the above-mentioned steps 4 comprises: with described Stokes optical signal and anti-Stokes light conversion of signals is two path signal, and carry out filtering, and the two path signal that converts linear relationship to carried out the ratio computing, the ratio that obtains according to computing carries out temperature computation, with, the temperature field information of acquisition scattered light scattering position x such as position 1 receives the reflected light 2 that sends behind a plurality of light pulse 2us continuously ¹⁸Inferior, repeat 2 then ¹⁸Inferior ratio computing obtains 2 ¹⁸Individual temperature field information is with 2 ¹⁸Individual temperature field information adds up, and can obtain in the position 1 the temperature field information that adds up like this; Utilize 16 sliding windows of 4 rank multinomials to carry out the distribution that the method for least square moving average obtains two-dimensional temperature field.Computer shows the temperature field scattergram, has promptly finished observation process one time.This process approximately needs 30 seconds.Simultaneously, laser instrument sends a light pulse, and detector can be collected the temperature information of a lot of positions in very short interval, is position 1 such as 2us, and 3us is position 2, and 4us is position 3, passes through above-mentioned 2 equally ¹⁸Add up after the inferior ratio computing temperature field of positions such as obtaining position 2, position 3, position 4 distributes.Therefore, by this detection method, the temperature field that utilizes sensor fibre can obtain each position of body surface distributes, thereby can judge patient's depth of anesthesia.

Wherein, to carry out temperature computation be to utilize to obtain temperature T (x) shown in the very simple following formula 2.7 of exponential relationship of the anti-Stokes light of scattered light scattering position x and the ratio R of Stokes light intensity [T (x)] and temperature to the ratio that obtains according to computing:

$R\left[T\left(x\right)\right]=\frac{P_{\mathrm{as}}\left[T\left(x\right)\right]}{P_s\left[T\left(x\right)\right]}={\left(\frac{{\mathrm{\λ}}_s}{{\mathrm{\λ}}_{\mathrm{as}}}\right)}^4\·\exp [-\frac{T_0}{T\left(x\right)}]\·\exp \{-[\mathrm{\α}\left({\mathrm{\λ}}_{\mathrm{as}}\right)-\mathrm{\α}\left({\mathrm{\λ}}_s\right)]\·x\}---\left(2.7\right)$

Wherein, λ _AsBe anti-Stokes optical wavelength and λ _sBe the Stokes optical wavelength, α (λ _As) the fibre loss coefficient and the α (λ that cause by Rayleigh scattering when anti-Stokes light light transmits in optical fiber _s) fibre loss that causes by Rayleigh scattering when in optical fiber, transmitting for stokes light light, α (λ _As) and α (λ _s) can obtain its value by the parameter that optical fiber dispatches from the factory; $T_0=\frac{\mathrm{hc\Δv}}{k_B}$ , h=planck constant, Δ v are Raman frequency shift, k=Boltzmann constant, c are the light velocity; T (x) is the temperature at position x; And x is some distance from the starting point of sensor fibre of sensor fibre.Can calculate the temperature at X place, position like this by above-mentioned formula (2.7), through repeating 2 ¹⁸Inferior ratio computing obtains 2 ¹⁸Individual temperature field information is with 2 ¹⁸Individual temperature field information adds up, and information like this can obtain adding up in the temperature field of position x; Utilize 16 sliding windows of 4 rank multinomials to carry out the distribution that the method for least square moving average obtains two-dimensional temperature field.

But utilize above-mentioned formula to obtain the temperature at x place, body surface position, wherein last is that fibre loss causes, this seriously influences temperature computation, therefore in actual measurement, can pre-determine known constant temperature T ₁The Raman ratio of sensor fibre each point under the condition, promptly on the position that needs are measured, add the steady temperature field of known temperature, such as 1 adding the T1 temperature field in the position, detect the reflected light signal that receives then, then anti-Stokes light and stokes light are carried out ratio, just can obtain the R[T of position 1 ₁(x): and R[T ₁(x) with the relation of temperature shown in formula 2.8:

$R\left[T_1\left(x\right)\right]={\left(\frac{{\mathrm{\λ}}_s}{{\mathrm{\λ}}_{\mathrm{as}}}\right)}^4\exp [-\frac{T_0}{T_1\left(x\right)}]\·\exp \{-[\mathrm{\α}\left({\mathrm{\λ}}_{\mathrm{as}}\right)-\mathrm{\α}\left({\mathrm{\λ}}_s\right)]\·x\}---\left(2.8\right)$

(2.7) formula and (2.8) formula are carried out ratio, the fibre loss that just can be eliminated influence

Value along the measurement temperature of optical fiber position: $\frac{1}{T\left(x\right)}=\frac{1}{T_1\left(x\right)}-\frac{1}{T_0}\·\ln \left(\frac{R\left[T\left(x\right)\right]}{R\left[T_1\left(x\right)\right]}\right),$ Thereby carry out temperature computation according to the ratio R [T (x)] that computing obtains and to utilize this formula $\frac{1}{T\left(x\right)}=\frac{1}{T_1\left(x\right)}-\frac{1}{T_0}\·\ln \left(\frac{R\left[T\left(x\right)\right]}{R\left[T_1\left(x\right)\right]}\right)$ Calculate the temperature field that obtains x place, position, wherein $T_0=\frac{\mathrm{hc\Δv}}{k_B},$ H=planck constant, Δ v are Raman frequency shift, and k=Boltzmann constant, c are the light velocity; T (x) is the temperature in the x position; And x is some distance from the starting point of sensor fibre of sensor fibre.。The method that adopt in the concrete temperature field that obtains x place, position is the same: through repeating 2 ¹⁸Inferior ratio computing obtains 2 ¹⁸Individual temperature field information is with 2 ¹⁸Individual temperature field information adds up, and information like this can obtain adding up in the temperature field of position X; Utilize 16 sliding windows of 4 rank multinomials to carry out the distribution that the method for least square moving average obtains two-dimensional temperature field.

The ratio of measuring anti-Stokes light intensity and Stokes light intensity is determined method of temperature like this, in fact can regard as and only utilize the entrained temperature information of anti-Stokes light to come thermometric, and stokes light is eliminated the influence of factors such as luminous power fluctuation, fibre loss to the anti-Stokes light intensity as the reference light source, also just overcome the defective of single channel anti-Stokes light demodulation method.

Depth of anesthesia checkout equipment of the present invention detects when being mainly used in carrying out local anesthesia to the patient, use this depth of anesthesia checkout equipment human body local anesthesia degree of depth in real time, utilize the technology of distributing optical fiber sensing, obtain easily that two-dimensional temperature field distribution situation and cost are low, spatial resolution is high, simple in structure.And the spatial resolution of this depth of anesthesia checkout equipment simple optical fiber is less than 1m; After human body twines, in the resolution of human body surface less than 1cm; Temperature resolution is less than 0.1 ℃; Response time is 30s; And can show the two-dimension temperature field pattern of detected part on computers in real time.The present invention also can be applied to general anesthesia, and is lower than general anesthesia detection range existing products cost, the equipment complexity is low, fast-response and can using on some special occasions such as in occasion that electromagnetic interference is arranged or the hearing impaired occasion of patient etc.

It should be noted last that, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (16)

1, a kind of depth of anesthesia checkout equipment, it is characterized in that comprising: light source provides device, and the pass that light impulse length and spatial resolution are satisfied in output is: $\mathrm{\ΔL}+\frac{t_w\×v_g}{2}$ Light pulse, v wherein _gBe the speed of light in optical fiber, t _wBe light impulse length;

First bonder provides device to be connected with described light source, is used to receive described light pulse and with its output and receiving scattered light and with its output, this scattered light power P _As=P α _AsSX (1-X) is α wherein _AsBe the Raman scattering coefficient, S is the backscattering factor and loss, and P is an input optical power, and X is the percentage ratio of input optical power and Output optical power;

Sensor fibre is connected with described first bonder, and described sensor fibre is imported in described light pulse, with described sensor fibre effect generation Raman scattering, by the 3rd outfan output scattered signal of first bonder;

Second bonder is connected with described first bonder, and being used for according to splitting ratio is scattered light to be divided into anti-Stokes light and stokes light in 90: 10;

The check and analysis device is connected with described second bonder, is used to survey Stokes optical signal and anti-Stokes optical signal and carries out signal processing analysis and demonstration.

2, depth of anesthesia checkout equipment according to claim 1 is characterized in that described second bonder is connected by optical fiber filter with the check and analysis device.

3, depth of anesthesia checkout equipment according to claim 2, the number that it is characterized in that described optical fiber filter is 2, it is anti-Stokes light λ that one of them optical fiber filter adopts centre wavelength _AsFirst wave filter, and another optical fiber filter to adopt centre wavelength be stokes light λ _sSecond wave filter, described first wave filter is connected with the check and analysis device with described second bonder respectively with second wave filter.

4, depth of anesthesia checkout equipment according to claim 1, it is characterized in that described first bonder comprises first input end, second end and the 3rd outfan, described first input end provides device to be connected with described light source, and described first input end receives described light pulse; Described second end is connected with sensor fibre, output optical pulse, and described further sensor fibre and described light pulse generation Raman scattering, the output scattered light is given described second end; And described the 3rd outfan is connected with second bonder, exports described scattered light.

5, depth of anesthesia checkout equipment according to claim 1 is characterized in that described light source provides device to comprise:

The laser modulation circuit is used to modulate the pass of satisfying light impulse length and spatial resolution and is: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse, v wherein _gBe the speed of light in optical fiber, t _wBe light impulse length;

Laser instrument is connected with described laser modulation circuit, is used to export the light pulse after the modulation.

6, depth of anesthesia checkout equipment according to claim 5 is characterized in that described laser modulation circuit comprises:

Drive circuit for laser is connected with described laser instrument, is used to drive described laser instrument output optical pulse;

Pulse-generating circuit is connected with described drive circuit for laser, is used for the pass that light pulse with laser instrument output is modulated into light impulse length and spatial resolution to be: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse;

Temperature feedback circuit is connected with laser drive circuit with described laser instrument, is used to survey the temperature of current lasers, laser temperature is adjusted in good time, guarantees that laser works is in stationary temperature.

7, depth of anesthesia checkout equipment according to claim 1 is characterized in that described check and analysis device comprises:

The PIN photodetector is connected with described wave filter, and being used for described Stokes optical signal and anti-Stokes light conversion of signals is two path signal;

The photoelectric current testing circuit is connected with described PIN photodetector, is used for the described signal of telecommunication of amplification filtering;

The antilogarithm computing circuit is connected with described photoelectric current testing circuit, is used for the electrical signal conversion after amplifying linear;

Voltage stabilizing circuit is connected with the antilogarithm computing circuit with described photoelectric current testing circuit, is used to provide voltage of voltage regulation;

Data collecting card is connected with described antilogarithm computing circuit, is used to gather the signal of telecommunication of handling through the antilogarithm computing circuit;

Processor with described data acquisition card connection, is used for two path signal is carried out the ratio computing, and the ratio that obtains according to computing carries out temperature computation, obtains the temperature field information of scattered light scattering position x, repeats 2 ¹⁸Inferior ratio computing obtains 2 ¹⁸Individual temperature field information is with 2 ¹⁸Individual temperature field information adds up, and utilizes 16 sliding windows of 4 rank multinomials to carry out the distribution that the method for least square moving average obtains two-dimensional temperature field.

8, according to any described depth of anesthesia checkout equipment of claim 1-7, it is characterized in that described first bonder is connected by temperature chamber with sensor fibre, described temperature chamber is used to provide constant temperature not to be subjected to the influence of ambient temperature to guarantee sensor fibre.

9, depth of anesthesia checkout equipment according to claim 5 is characterized in that described laser instrument is that power is 2w, and centre wavelength is 808.6nm, spectral width 1.6nm, and operating current is 1.5A.

10, depth of anesthesia checkout equipment according to claim 1 is characterized in that described sensor fibre is high germnium doped fiber, and it mixes germanium concentration is 10mol%.

11, depth of anesthesia checkout equipment according to claim 7 is characterized in that described photoelectric current testing circuit adopts logafier AD8304.

12, depth of anesthesia checkout equipment according to claim 1 is characterized in that described first bonder is a Y type directional coupler, and its splitting ratio is 50: 50.

13, a kind of depth of anesthesia detection method is characterized in that comprising:

The pass that light impulse length and spatial resolution are satisfied in output is: $\mathrm{\ΔL}=\frac{t_w\×v_g}{2}$ Light pulse, v wherein _gBe the speed of light in optical fiber, t _wBe light impulse length;

Light pulse after overcoupling with sensor fibre effect generation Raman scattering, produce scattered light, this scattered light power P _As=P α _AsSx (1-x) is α wherein _AsBe the Raman scattering coefficient, S is the backscattering factor and loss, and P is an input optical power, and x is the percentage ratio of input optical power and Output optical power;

Scattered light is to be divided into anti-Stokes light and stokes light at 90: 10 according to splitting ratio; And survey Stokes optical signal and anti-Stokes optical signal and carry out signal processing analysis and show.

14, depth of anesthesia detection method according to claim 13, it is characterized in that the described signal processing analysis that carries out comprises: with described Stokes optical signal and anti-Stokes light conversion of signals is two path signal, and carry out filtering, and the two path signal that converts linear relationship to carried out the ratio computing, carry out temperature T (x) calculating according to the ratio R [T (x)] that computing obtains, obtain the temperature field information of scattered light scattering position x, repeat 2 ¹⁸Inferior ratio computing obtains 2 ¹⁸Individual temperature field information is with 2 ¹⁸Individual temperature field information adds up, and utilizes 16 sliding windows of 4 rank multinomials to carry out the distribution that the method for least square moving average obtains two-dimensional temperature field.

15, depth of anesthesia detection method according to claim 14 is characterized in that the described ratio R that obtains according to computing [T (x)] carries out temperature T (x) and be calculated as: the exponential relationship of utilizing the anti-Stokes light of scattered light scattering position x and the ratio R of Stokes light intensity [T (x)] and temperature: $R\left[T\left(x\right)\right]=\frac{P_{\mathrm{as}}\left[T\left(x\right)\right]}{P_s\left[T\left(x\right)\right]}={\left(\frac{{\mathrm{\λ}}_s}{{\mathrm{\λ}}_{\mathrm{as}}}\right)}^4\·\exp [-\frac{T_0}{T\left(x\right)}]\·\exp \{-[\mathrm{\α}\left({\mathrm{\λ}}_{\mathrm{as}}\right)-\mathrm{\α}\left({\mathrm{\λ}}_s\right)]\·x\}$ Obtain temperature T (x); Wherein, λ _AsBe anti-Stokes optical wavelength and λ _sBe the Stokes optical wavelength, α (λ _As) the fibre loss coefficient that causes by Rayleigh scattering when anti-Stokes light light transmits in optical fiber, α (λ _s) fibre loss that causes by Rayleigh scattering when in optical fiber, transmitting for stokes light light; $T_0=\frac{\mathrm{hc\Δv}}{k_B},$ H=planck constant, Δ v are Raman frequency shift, and k=Boltzmann constant, c are the light velocity; T (x) is the temperature at position x; And x is some distance from the starting point of sensor fibre of sensor fibre.

16, depth of anesthesia detection method according to claim 14 is characterized in that the described ratio R that obtains according to computing [T (x)] carries out temperature T (x) and be calculated as: utilize $\frac{1}{T\left(x\right)}=\frac{1}{T_1\left(x\right)}-\frac{1}{T_0}\·\ln \left(\frac{R\left[T\left(x\right)\right]}{R\left[T_1\left(x\right)\right]}\right)$ Obtain; R[T wherein ₁(x) be position x temperature T ₁The time anti-Stokes light that records and the ratio of stokes light; $T_0=\frac{\mathrm{hc\Δv}}{k_B},$ H=planck constant, Δ v are Raman frequency shift, and k=Boltzmann constant, c are the light velocity; T (x) is the temperature in the x position; And x is some distance from the starting point of sensor fibre of sensor fibre.

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