CN2618219Y - Anesthetic monitor - Google Patents

Abstract

The utility model relates to an anesthesia monitoring device, comprising a short pure tone stimulus signal source, a white noise signal source, an amplifying circuit device of low-noise and high-precision physiological signals and a data collecting and data analyzing and processing system. A short pure tone sound signal with a fixed repeated stimulating frequency of 35Hz-45Hz is used to stimulate patients to repeatedly obtain the waveform changes of steady auditory evoked potentials; and through a simple and easy digital processing system and method, the interferences are conveniently and reliably rejected, and the effective waveforms are kept, so the auditory steady state response (ASSR) index and the trend graph of the anesthesia monitoring device which are steady and reliable and which can intuitively, quantitatively and continuously display the patient anesthesia state are conveniently and rapidly calculated, thus the utility model can be more reliably adapting to the strong interference environment of operating rooms, enabling anesthesia doctors to reliably master the anesthesia state of patients and to get the unprecedented information, being favorable to avoid the sequela of patients initiated by the general anesthesia. Thus the cost is reduced, and the benefit is increased.

Description

A kind of anesthesia monitoring device

Technical field

The utility model relates to a kind of anesthesia monitoring device, and particularly a kind of utilization monitoring auditory evoked potential (AEP---Auditory Evoked Potentials) is monitored the device of safe depth of anesthesia and flesh pine degree.

Background technology

Anesthesia (Anesthesia) is with medicine or non-medicine, make a part of swound of patient's whole machine body or body, to reach painless purpose, it is the important leverage of carrying out medical operating, but at present in the general anesthesia operation, there is 1%～2% patient can in art, know (anesthesia kicks the beam), causes outpatients mental state unhappiness, frightened operation etc.; Also exist in addition owing to anaesthetize and make the recover case of difficulty even death of patient deeply, so a kind of method and the instrument that can monitor depth of anesthesia reliably, continuously, quantitatively of urgent clinical needs, so that the basis for estimation of anaesthetizing the more reliable science of doctor to be provided.

Existing anesthesia detects and mainly contains following several method:

1, traditional sign method.The anesthetist is divided into ＂ light anaesthesia/average of operation periods according to the basic sign of patient (mainly being breathing, the circulation system, eye movement characteristics or the like) with anesthesia and anaesthetize/anaesthetizes ＂ deeply.But, owing in operation, generally use muscle relaxant, under the situation of control breathing, keep anesthesia again, therefore can not judge the anesthesia depth with the breathing situation; The pupil sign is subject to the influence of used medicine, neither a preferable index; And blood pressure stabilization can only illustrate that anesthesia is not dark, can not disclose other states.Therefore, relying on this traditional ＂ multi-parameter monitor ＂, is the depth of anesthesia that is difficult to reflection patient comprehensively.

2, blood gas analysis method (Hemodynamics method).Such as the present existing method of utilizing infrared spectrophotometer/mass spectrum and the light anaesthesia of gas chromatography district, moderate anesthesia, dark anesthesia etc.But to reach the required anesthetic concentration of stage of surgical anesthesia to different people individual difference is arranged; To wait until that in addition to reach after the balance blood level between alveolar/blood/tissue just meaningful.Therefore, this method can only must combine with clinical sign as a supplementary means judging depth of anesthesia.

3, traditional eeg monitoring method.Show as corticocerebral electrical activity holddown during anesthesia on the electroencephalogram, correlativity is arranged, so electroencephalogram also can be used as the supplementary means of judging depth of anesthesia with the blood level and the anaesthesia depth sign of arcotic.The brain electricity change that the anesthesia doctor will anaesthetize overall process is summarized as each species specific electroencephalogram (ripple), from rhythmicity, amplitude variations, explosive inhibition situation or the like, discerns the depth of anesthesia.The greatest problem that eeg monitoring is used for anesthesia monitoring is because the signal waveform complexity, the anesthetist often seems that to the specific recognition of EEG unable to do what one wishes (specificity is too many, the factor of influence is also many), use throughput in the preceding art of different arcotics, art etc. that the influence of electroencephalogram also is not quite similar in addition.

4, brain electricity bispectral index analytic approach (BIS): utilize computer technology EEG signals to be carried out the automatic analysis of frequency characteristic and phase propetry, comprehensively extract the index of a kind of easy sign brain electricity different frequency composition component and level of consciousness corresponding relation, i.e. the BIS value.As the BIS system of U.S. spacelab SPACELAB, under waking state, frequency is very fast, and BIS is near 100.As seen the situation of reviving of BIS fine prediction anaesthetic metabolite clearance of energy and anesthesia is the good index of monitoring sedation depth, also is one of simple and easy to do effective ways.But, BIS can not monitor well from consciousness and disappear to clear-headed transitional period variation, be not so good as heart rate variability index HRV aspect the reliability of reflection sedation depth, and BIS is invalid to some anaesthetic, and be subject to influences such as myoelectricity and working environment, disturb shortcomings such as individual difference is bigger.

5, bring out the potential monitoring method.The process that human body is anaesthetized, generally from the reticulate texture of cerebral cortex/brain stem, basad nuclear/oblongata direction develops, and the change of bringing out current potential thus is very obvious, and with the blood level and the anaesthesia depth sign of arcotic better correlativity is arranged.Therefore, bring out in the technological means that current potential is current clinical monitoring depth of anesthesia the most rising a kind of.Bring out the kind more (AEP/VEP/SEP etc.) of current potential, different kinds has different characteristics, and the most ripe is to be the potential monitoring that brings out of characteristic with middle long latency auditory evoked potential (MLAEP) at present.PCT/DK00/00623 (publication number the is WO 01/74248 A1) patented claim of Denmark special A/S (DANMETER A/S) company is disclosed as WIPO, it mainly is to utilize patient's auditory evoked potential (AEP) that reaction is produced for a repetition sonic stimulation to repeat to extract AEP and extract AEPI AAI with rapid extraction method and superposed average method in conjunction with its exclusive autoregressive model, make depth of anesthesia become 0～100 monitoring index, thereby distinguish patient's clear-headed and narcosis intuitively, but this monitoring method is because the AEP signal is very weak, signal to noise ratio (S/N ratio) is extremely low, cause the poor stability of monitor system, a little less than the antijamming capability, requirement to working environment is very high, performance is unstable in general surgical environments, monitoring effect is not good, influences it and applies.Be the analysis-by-synthesis object with transient state AEP index in the particularly this method, its index that calculates is disturbed easily and false index occurred, influences the judgement of anesthetist to depth of anesthesia.

Summary of the invention

The purpose of this utility model is the problem at above-mentioned existence, provide a kind of tone burst voice signal of fixing 35HZ～45HZ repetitive stimulation frequency that utilizes to stimulate patient repeatedly to obtain stable state auditory evoked potential (AEP---Auditory Evoked Potentials) wave form varies, and it is convenient, reliably by simple, be easy to digital processing method and reject interference, keep effective waveform and calculate reliable and stable also energy quickly and easily intuitively, quantitatively, the anesthesia monitoring device that shows patient narcose auditory steady-state evoked response Index A SSR and trend map continuously, thereby make the utility model can adapt to the strong interference environment of operating room more reliably, make the Anesthetist more can grasp patient's narcosis reliably, make the Anesthetist obtain unprecedented information, help the sequelae of as far as possible avoiding patient to cause because of general anesthesia, the surgeon is not blocked when operation, and minimizing anaesthetic using dosage, improve patient's recovery time, shorten patient's hospital stays, thereby reduce cost, increase benefit.

The technical solution of the utility model is achieved in that

A kind of anesthesia monitoring device comprises:

The voice signal that is used to produce 35Hz～45Hz repetition frequency stimulates patient to be measured to detect the short tone burst stimulation signal generating source of ear and is used to produce continuous voice signal and with the white noise signal that shields another ear of patient to be measured the source takes place;

Be used to extract patient's to be measured auditory evoked potential (AEP) signal and to this auditory evoked potential (AEP) signal amplifies, filtering and analog to digital conversion (A/D) are handled low noise high precision physiological signal amplifier circuit device;

Be used to receive auditory evoked potential (AEP) signal through low noise high precision physiological signal amplifier circuit device, and this auditory evoked potential (AEP) signal by stages section carried out superposed average step by step and obtain the average waveform figure of each segment stable state auditory evoked potential signal, and according to latent period or the wave amplitude of the average waveform figure of each segment or the corrugated is long-pending or auditory steady-state evoked response (ASSR) exponential quantity of each segment is calculated in its combinatory analysis, and the data acquisition and the data analysis disposal system of the time dependent trend map of demonstration auditory steady-state evoked response (ASSR) exponential quantity.

Describe basic structure of the present utility model and principle of work in detail below in conjunction with accompanying drawing:

Description of drawings

Fig. 1 is the block diagram of system of the present utility model;

Fig. 2 is the composition synoptic diagram of tone burst described in the utility model;

Fig. 3 is a tone burst described in the utility model and the corresponding potential waveform contrast synoptic diagram that brings out;

Fig. 4 is terminal show state figure of the present utility model;

Fig. 5 is the process flow diagram of data acquisition described in the utility model and data analysis disposal system;

Fig. 6 is the electrical schematic diagram of the utility model pre-amplification circuit;

Fig. 7 is the electrical schematic diagram of the rearmounted amplifying circuit of the utility model;

Fig. 8 is the electrical schematic diagram of the utility model amplifier control circuit;

Fig. 9 is the electrical schematic diagram of the utility model CPU (central processing unit) (MCU);

Figure 10 is the electrical schematic diagram of the utility model sine wave/method generator (SIN/QUA Generator);

The electrical schematic diagram of the utility model A/D conversion among Figure 11;

Figure 12 is the electrical schematic diagram of the utility model numeral photoelectricity isolated location;

Figure 13 is the electrical schematic diagram of the utility model USB interface;

Figure 14 is the electrical schematic diagram of the utility model DC-DC insulating power supply;

Figure 15 is the tone burst generation circuit electrical schematic diagram of the utility model 40Hz repetitive stimulation frequency.

Embodiment

As shown in Figure 1, anesthesia monitoring device described in the utility model comprises:

(wherein the repetitive stimulation frequency is preferably 40Hz to be used to produce 35Hz～45Hz repetition frequency, select 40Hz in the present embodiment for use, make that like this auditory evoked potential (AEP) that extracts also is that a frequency is 40Hz or the sine wave signal that is similar to 40Hz especially, be that the steady-state signal frequency band concentrates on 40Hz, thereby the easy signal that extracts by simple Filtering Processing and just can obtain stable waveform signal by minority superposed average several times, be convenient to follow-up processing, and this also is one of emphasis of the present utility model.) voice signal stimulate patient to be measured to detect the short tone burst stimulation signal generating source of ear and be used to produce continuous voice signal and the source takes place with the white noise signal that shields another ear of patient to be measured;

Be used to extract patient's to be measured auditory evoked potential (AEP) signal and this auditory evoked potential (AEP) signal carried out the low noise high precision physiological signal amplifier circuit device of power amplifier, filtering and analog-to-digital conversion process;

Be used for receiving auditory evoked potential (AEP) signal through low noise high accuracy physiological signal amplifier circuit device; And this auditory evoked potential (AEP) signal by stages section carried out superposed average step by step and obtain the average waveform figure of the Steady-state evoked potential signal of each segment, and according to incubation period or the wave amplitude of the average waveform figure of this segment or the corrugated is long-pending or auditory steady-state evoked response (ASSR) exponential quantity of each segment is calculated in its combinatory analysis and show data acquisition and the data analysis treatment system of the time dependent tendency chart of this auditory steady-state evoked response exponential quantity (ASSR).

Wherein above-mentioned 35Hz～45Hz short tone burst stimulation signal generating source comprises:

Be used to produce the crystal oscillator of the sinusoidal wave digital voice signal of 200Hz～5KHz and time-frequency division produce circuit and prestore the standard sine wave signal can automatically controlled memory EEPROM or flash memory FLASH MEMORY;

Be used for the D/A converting circuit that 200Hz～5KHz frequency voice signal carries out digital-to-analog conversion through crystal oscillator and time-frequency division circuit;

Be used for producing the timing modulation circuit of the tone burst voice signal of 35Hz～45Hz repetition frequency to regularly modulating through the carrying out of D/A converting circuit;

Be used for 35Hz～45Hz repetition frequency tone burst voice signal is carried out the audio power amplifier circuit of processing and amplifying;

The tone burst voice signal that is used for the 35Hz～45Hz repetition frequency that will handle through audio power amplifier circuit is transmitted to the earphone that patient to be measured detects ear.

Wherein in the present embodiment for ease of the operation and the debugging, patient's two ears can be tested respectively under the situation of not changing earphone, as shown in figure 15, above-mentioned 35Hz in the present embodiment～45Hz tone burst signal generating circuit is a tone burst generation circuit of selecting 40Hz repetitive stimulation frequency for use.Wherein U23 is No. 3 programmable timers, the Kai Heguan that controls the tone burst of left and right acoustic channels respectively by the PULSER0 and the PULSEL0 of its timing controlled output; U42, U43 are the D/A conversion chips, they and amplifier U38, U39, U40, U41 export the analog voltage corresponding to digital signal together, when selecting the frequency of tone burst, the sinusoidal waveform digital signal sequences that storage in advance is good will be delivered to D/A converter continuously, cooperates reference voltage VREF, produces the required voltage waveform, when VREF is constant, can produce sine wave, when VREF is white noise, but the intensity of modulating white noise; U44, U45 are the analog channel selector switchs, are used to control the time-histories passage different with gating of tone burst; The U31 latch control signal, the passage of control analog switch U46, U47, U48 and U44, U45 switches; U46 is operatively connected to the benchmark numeration frequency of timer U23; Enabling of U47 control tone burst time-histories control signal; The reference voltage of U48 control gating D/A is constant voltage or white noise voltage; U35 is the 3-8 address decoder, is used for the transmission object of address selection data channel; M2 crystal oscillator and phase inverter U57A, U58, U59 constitute the digital signal that oscillatory circuit produces 8MHz, become 2MHz, the 1MHz of dutycycle 50% and the square wave of 250KHz through counter U60, the shaping of U61 frequency division, offer timer U23; U34 latch control signal MASKEN, its determines the work of white noise circuit and stops; U62, U63, U64, U65, U66A, U67A, U68 form digital pseudo random signal and produce circuit, and it can produce a signal immediately that covers audiorange, we with it can well the analogue audio frequency scope white noise; Form 3 grades of filtering circuits to the noise beyond the white noise signal filtering audiorange of front by amplifier U84A, U86,87, U85 and resistance capacitance on every side thereof, and drive white noise signal to the D/A reference edge; Formed the power amplification driver element of left and right acoustic channels by amplifier U69A, U69B, U70A, U70B, U71A, U71B, U72A, U72B and resistance capacitance triode on every side thereof etc., the white noise of tone burst or shielding usefulness is amplified to is enough to promote to stimulate earphone or special-purpose audio amplifier.

Above-mentioned low noise high precision physiological signal amplifier circuit device comprises:

Near at least two electrodes in order to extraction auditory evoked potential signal of device patient's auditory center nerve to be measured;

Be to select three electrodes for use in the present embodiment, wherein positive electrode places patient's frons, reference electrode is placed on the left front volume of patient, negative electrode is placed on patient's ear rear portion (preferably be positioned at ear after real bone place), the placement of certain above-mentioned electrode can be varied, so long as be placed near the nerve center of head promptly passable.

Be controlled by calibration and impedance measurement signal generation circuit and control signal latch cicuit in order to improve input impedance and the front buffer amplifying circuit of driving force with the shielding input channel is provided;

Be controlled by the control signal latch cicuit in order to suppress noise level, to improve the preposition differential amplifier circuit of gain;

Be controlled by the control signal latch cicuit in order to suppress the power frequency codan that power frequency is disturbed;

Be controlled by the 4 grade 2 rank low-pass filter circuit of control signal latch cicuit in order to the unnecessary high-frequency signal of filtering;

Be controlled by the control signal latch cicuit and be fit to carry out analog-to-digital programme-controlled gain amplifying circuit in order to signal is amplified to;

Be controlled by the high-pass filtering circuit of control signal latch cicuit in order to the unnecessary low frequency signal of filtering;

Be controlled by the control signal latch cicuit in order to signal is sampled and analog-to-digital analog to digital conversion circuit;

In order to receive under above-mentioned data acquisition and the data analysis system control signal that passes and translate into corresponding steering order, control the gain control, power frequency trap etc. of amplification channel by the control circuit latch signal and extract analog to digital conversion (A/D) after digital signal and be uploaded to data acquisition and the single chip machine controlling circuit of data analysis system;

Realize the control signal latch cicuit that amplification channel is controlled in order to cooperate single chip machine controlling circuit;

Whether the gain in order to the self check amplification channel normally reaches the calibration impedance measurement signal generation circuit that whether the detection potential electrode contacts in measuring process with frequency band.

The each several part of wherein above-mentioned auditory evoked potential signal Processing can adopt existing related techniques and be adjusted promptly and can realize, select for use a kind of the most general circuit of fundamental sum to realize in the present embodiment, its circuit theory such as Fig. 6～shown in Figure 14, its concrete principle of work is:

Fig. 6 is the preposition amplifier section schematic diagram in the low noise high precision physiological signal amplifier.Be positioned over and be delivered to this circuit by cable after supraneural electrode picks up the brainstem auditory evoked signal, the back level is delivered in the signal amplification by the differential preamplifier that U6A, U6B, U1 and R5, R6, R7, R8, R9, R10, C14, C15, R15, R16, R17, R11, R12, R13, R14 form; R1, R2, Q1, Q2, Q3, Q4, Q5, Q6 form input protection circuit; U2, U3, U4 are used for ride gain, switch impedance measurement, switch self-correcting circuit etc.

Fig. 7 is the rearmounted amplifier section schematic diagram in the low noise high precision physiological signal amplifier.C1, R1, R2, C2 and U7 form the bandpass filtering programmable amplifying circuit; U2A, U2B and R17, R18, R19, C5, C6, C7, C8, C12, C13, R3, R4, R24, R25, R26 form the 50Hz trap circuit, and the unnecessary power frequency of filtering is disturbed; U3A, U3B, U4A, U4B and R12, R16, C22, C23, R5, R6, C24, C25, R7, R8, C26, C27, R9, R10, C28, C29 form 4 grade of 2 rank low-pass filter circuit, filtering high frequency interference; R13, R15, C14, C20, U5 form the bandpass filtering programmable amplifying circuit; C17, R14, U6 constitute high pass and drive buffer circuit.

Fig. 8 is the digital control part schematic diagram in the low noise high precision physiological signal amplifier.U7 latch address signal; U9 driving data bus; U3, U4, U5, U6, U8 latch the corresponding digital control signal, comprise that gain control, trap circuit switch, filtered band are selected, impedance measurement enables, the instrument self-correcting;

Fig. 9 is the MCU part of circuit control signal, and U2 is a single-chip microcomputer 8051, is responsible for accepting the steering order of computing machine and translates into corresponding actions, and control signal is latched in the corresponding latch; U3 is the voltage stabilizing chip provides 3.3V to U2 a power supply; U1 is the watch dog monitoring chip, is responsible for monitoring and guaranteeing the normal operation of U2.

Figure 10 is sinusoidal wave square wave generation circuit, and R1, R2, R3, R4, C3, C5, C6 form filter network square-wave signal is converted to sine wave, and U1D provides direct driving output; U1C, R9, R10, C4 adjust gain; U1A, U1B form differential drive signal VS+ and VS-.

Figure 11 is that signal sampling keeps and change-over circuit, U1 carries out channel selecting, U3, C9, R4, R5 carry out shaping and buffering to signal, U2 is the A/D conversion chip, have 16 precision, adopt 16 parallel bus interface, utilized 8 interfaces in this patent, time division multiplex least-significant byte data bit is finished 16 accuracy A/D data and is accepted; C2 is the electric capacity of A/D sampling; RW2, R3 regulate reference voltage; RW1, R2 finely tune total null voltage; U4 accepts the buffering driving for bus provides, and guarantees the true(-)running state of bus.

Figure 12 is the photoelectric isolating circuit of digital controlled signal part.U1, U2, U3 are 5 road photoelectronic couplers, and this photoelectronic coupler provides anti-dielectric strength more than 2500 volts, because the sampling electrode of prime contact with human body, so need take certain insulation blocking measure with applying portion on electric.

Figure 13 is the communication interface circuit between data command and the computing machine.U2 is a memory chip, be used as metadata cache, U1 is the singlechip control chip of band USB interface, this chip is observed the USB1.1 agreement, top speed reaches 12Mbit/s, supports plug and play, can be connected with the computer system that has USB interface, utilize the powerful processing power of computing machine, a plurality of input channels can be expanded again easily in a Computer Processing center simultaneously.U3, the U4 resistance capacitance around having reached, the power supply voltage stabilizing of the 5V voltage that provides from USB offers U1 and U2 to 3.3V.

Figure 14 is the insulating power supply partial circuit to whole circuit supplies.The direct current of+12V is through behind the filter network of LCR, enter DC-DC isolated variable module U1 and U2, behind the isolated variable after filtration after ripple and the voltage stabilizing, output ± 5V float power FAV+ and FAV-, and+5V float power FDV, U3, U4, U5, U6, U7, U8 are the voltage stabilizing output modules.

As Fig. 1～shown in Figure 4, the method for utilizing anesthesia monitoring device described in the utility model to carry out anesthesia monitoring may further comprise the steps:

1), stimulates patient's to be measured ears simultaneously with the 35Hz～short tone burst stimulation signal of 45Hz repetition frequency; Or with the short tone burst stimulation signal stimulus patient's to be measured of 35Hz～45Hz repetition frequency detection ear, and shield another ear of patient to be measured with white noise or other voice signal; Wherein the formation of tone burst and composition are such: at first the pure tone stimulator produces tone burst.Pure tone is directly to drive the pronunciation unit by unifrequent sinusoidal waveform, superimpose rectangles or trapezoid window on frequency employing 200Hz～5Khz interval of pure tone and gradable adjustment, the pure tone, form tone burst, window time-histories width 13 be 1～25 millisecond adjustable, as shown in Figure 2, trapezoidal window can be divided into rising edge 14, platform 15, negative edge 16, generally accounts for 10%～30%, 80%～40%, 10%～30% of time-histories width respectively.As shown in Figure 3, wherein in the present embodiment tone burst with 40Hz, repetition frequency, with the adjustable stimulation intensity of sound of 40～100dB classification, stimulate patient's ear by conductance earphone or osophone, shield with white noise picking up the ears.Select for use 40Hz to make that like this auditory evoked potential (AEP) that extracts also is that a frequency is 40Hz or the sine wave signal that is similar to 40Hz especially in the present embodiment, be that the steady-state signal frequency band concentrates on 40Hz, thereby the easy signal that extracts by simple Filtering Processing and just can obtain stable waveform signal by minority superposed average several times, be convenient to follow-up processing, and this also is one of emphasis of the present utility model.

2), at least two electrode assemblies are picked up the auditory evoked potential signal of repetition near patient's to be measured nerve center;

Be to select three electrodes for use in the present embodiment, wherein positive electrode places patient's frons, reference electrode is placed on the left front volume of patient, the ear rear portion that negative electrode is placed on patient (preferably is positioned at the real bone place behind the ear, the placement of certain above-mentioned electrode can be varied, so long as be placed near the nerve center of head promptly passable.

3), the auditory evoked potential signal that picks up is carried out amplification, filtering and the A/D conversion process of signal;

4), as shown in Figure 4, auditory evoked potential digital signal is after treatment sampled, and whole auditory evoked potential digital signal is divided into the segment that several length are L in regular turn, be that each segment of L is subdivided into again with h again with length be that minizone section that N length of sliding step is M is pursued minizone section superposed average and handled, and as the described length of analytical calculation the window waveform of segment auditory evoked potential reaction (ASSR) index of L with the average waveform behind the superposed average step by step of each minizone section, wherein in the present embodiment, carrying out that superposed average handles is when bringing out the Digital Signal Analysis of electric potential signal after through the A/D conversion, number be divided into the segment that several length are L in regular turn, the time span in general L interval can be 2S, when sampling rate was 4KHz, L length of an interval degree was 8000; It is that minizone section that N length of sliding step is M is carried out superposed average and handled that the L segment is subdivided into again with h, sliding step h is the integral multiple in stimulus signal cycle, if frequency of stimulation is 40Hz, then stinging flyback cycle is 25mS, usually, sliding step h can 4 times the thorn flyback cycles, be exactly 100mS, when sample frequency was 4KHz, h was exactly 400 points; The length M of minizone generally also is the integral multiple of thorn flyback cycle, and as shown in Figure 4, choosing in the present embodiment at 400 is that each window waveform has 4 sine waves; And N=L/h, the N value is exactly 20 like this; The length that obtains after this N minizone section superposed average handled is that the average waveform of M is exactly the average window waveform as the steady-state induced potentiometric response index of this L segment of analytical calculation, the signal of the segment by choosing certain-length carries out simple superposed average and handles and just can obtain stable waveform and by this waveform analysis is obtained reliable result like this, both simplified handling procedure, accelerate the waveform refreshing frequency (0.5～2S is refreshable once result) of window, make subsequent analysis processing more reliable and more accurate again.Wherein the computing formula of superposed average is step by step:

In the wherein above-mentioned formula:

Yj represents the superposed average wave amplitude that j is ordered in the selected segment;

X _{(i * h+j)}Represent this segment (i * h+j) wave amplitude of individual sampled point, the i.e. wave amplitude of j sampled point of i minizone section;

H represents selected segment is divided into the step-length that each minizone section of superposeing after N the minizone section moves, and is the integral multiple in stimulus signal cycle;

N represents selected segment L is divided into the number of a plurality of minizones section;

J represents the sequence number of the point in the window waveform to be analyzed;

I represents the sequence number of the minizone section that is used to superpose;

Span 0～M-1 of i wherein

Span 0～h-1 of j

The span 100～2000 of M preferably 400

The span 100～2000 of h preferably 400

The span 5～500 of N preferably 20

L is the original burst length of analyzing that brings out electric potential signal, and span is 2000～100000, best 8000

Wherein the pass between N, h and the L is: L=N * h

5) will show in regular turn as the window waveform of brushing number through the average waveform on each segment after above-mentioned the 4th step processing, and according to latent period of each window waveform or wave amplitude or the corrugated is long-pending or the auditory evoked potential reaction ASSR index that analyzing and processing obtains each segment is carried out in its combination, and each ASSR index shown synchronously become the time dependent trend map of ASSR exponential quantity, like this by simultaneously to the wave amplitude of the average waveform that obtains above, long-pending and ripple latent period of corrugated and before several times the reaction calculated value that brings out to carry out obtaining behind a series of related operation range of results be that 0～100 exponential quantity is come corresponding patient's to be measured various states, both guaranteed its visual result, easily handle, fully guaranteed its result's accuracy and reliability again, this also is one of emphasis of the present utility model.Wherein the computing formula of ASSR index is as follows:

ASSR _tRepresent the t ASSR index of window constantly;

A _tRepresent t constantly corresponding segment bring out the reaction calculated value;

A _{T-Δ t}Represent t-Δ t constantly corresponding segment bring out the reaction calculated value;

A ₀A when representing normal person's waking state _tValue is the clinical experience data;

K represents to quote altogether preceding k time and brings out the length that the reaction calculated value is brought weighted calculation into

a ₀... a _{Δ t}The expression weighting coefficient;

W _tRepresent the intermediate form of t window average waveform analysis data constantly, formula is seen below

The span of each coefficient in the above-mentioned formula:

A ₀ Be 10～55 generally to get 16

K round numbers, representative value get 1,2,3 etc.

a ₀... a _{Δ t}The weighting coefficient number is k+1, and its scope is between 0～1, and representative value is

When k=1, a ₀=0.75, a ₁=0.25;

When k=2, a ₀=0.65, a ₁=0.25, a ₂=0.1;

When k=3, a ₀=0.6, a ₁=0.25, a ₂=0.1, a ₃=0.05;

Wherein the narcosis of the ASSR index correspondence that draws by the aforementioned calculation formula is:

70＜ASSR＜100 waking states

50≤ASSR＜70 Somnolences

The slight narcosis in 30≤ASSR＜50

0＜ASSR＜30 deep anaesthesia states

Wherein above-mentioned W _tRepresent the intermediate form of t window average waveform analysis data constantly, its computing formula is:

Wt＝a _g×A _g(t)+b×S _(t)+c×f _(t)

Wherein Ag (t) expression t constantly the g kind wave amplitude calculated value of average waveform of corresponding segment, wherein the span of g is 1～4;

s _(t)Represent that t constantly amasss calculated value in the corrugated of the average waveform of the corresponding segment of institute;

f _(t)Represent t constantly latent period of average waveform of corresponding segment;

a _gRepresent t constantly the weighting coefficient of the 9th kind of wave amplitude calculated value of average waveform of corresponding segment;

B represent t constantly the weighting coefficient of preclinical calculated value of average waveform of corresponding segment;

C represent t constantly the weighting coefficient of preclinical calculated value of average waveform of corresponding segment;

The span of each coefficient is in the wherein above-mentioned formula:

a ₁=0～40 preferably 4

a ₂=0～20 preferably 2

a ₃=0～3 preferably 0.7

a ₄=0～10 preferably 1

B=0～1 preferably 0.001

C=0～10 preferably 2

Wherein calculate formula W t=a in the above-mentioned steps 5 _g* Ag (t)+b * S _(t)+ c * f _(t)Described in Ag _(t), S _(t), f _(t)Computing method obtain like this:

Window waveform at first above-mentioned be exactly to length be L to bring out the length that electric potential signal carries out obtaining behind the superposed average be the average waveform of M, it represents the electric potential signal that brings out of L.Average waveform length is an integer stimulus signal periodic waveform, and the typical case is 4 cycles choosing as present embodiment, so for the 40Hz stimulus signal, the time span of average waveform is 100ms, just 400, and the unit of average waveform amplitude is uV, long measure is mS, corresponding 0.25mS/ point.Following analysis all is at average waveform.

1, wave amplitude Ag _(t)Extraction and computing method the wave amplitude of average waveform is had multiple measuring method:

Method 1 is measured crest or trough to zero line (V just ₀, be the mean value that an amplitude is arranged in the average waveform) distance.If average waveform M length is 100ms, then comprise 4 complete waveform in wherein, have 8 crests and trough, the mean value of getting them is A ₁, its weighting coefficient is designated as a ₁

Method 2 is each complete waveform vertical ranges from the crest to the trough.If the length of average waveform M is 100ms, then wherein comprise 4 complete waveform, have 4 peak-to-valley values, the mean value of getting them is A ₂, its weighting coefficient is designated as a ₂

Method 3 is difference amplitude product point-scores, is applicable to the irregular waveform of COMPUTER CALCULATION.Formula is

$A_3=\underset{i=0}{\overset{M-2}{\mathrm{\Σ}}}|V_{i+1}-V_i|$

V _iV _I+1Represent i and i+1 point range value respectively

When M was 400, the i scope was 0～398

The weighting coefficient of its correspondence is a ₃

Method 4: being all square integral method of difference amplitude, is the improvement of the 3rd kind of method, and formula is

$A_4=\underset{i=0}{\overset{M-2}{\mathrm{\Σ}}}\sqrt{|V_{i+1}-V_i|}$

V _iV _I+1Represent i and i+1 point range value respectively

When M was 400, the i scope was 0～398

The weighting coefficient of its correspondence is a ₄

2. S is amassed on the corrugated _(t)Extraction and calculating

The corrugated is long-pending be meant bring out in the average waveform area that waveform covers and, because waveform has been a digital signal after entering computing machine, it is long-pending generally can to calculate the corrugated like this:

S＝∑|V _i-V ₀|

I is the sequence number of each sampled point in the average waveform, if the average waveform length M is 400, and 0＜i＜400 then

V _iIt is the wave-shape amplitude that i is ordered in the average waveform

V ₀Be the mean value that an amplitude is arranged in the average waveform.

Latent period f _(t)Extraction calculate

Begin to be called latent period from stimulation to the waveform that brings out that this stimulation occurs.General preclinical calculating has 2 kinds: method 1 is to be basis with the starting point of bringing out waveform, and this method accurately has certain difficulty in the identification at computing machine, and error is big easily; Method 2 is to be foundation with the summit that brings out waveform, and this is than being easier to identification.Because this method is the change of calculating the value of hiding, and is a kind of change value, therefore the result that draws of 2 kinds of methods is very approximate, and weighting coefficient also is the same, it should be noted that in the calculating that once adopts the same method in the measurement together.The computing formula that change latent period is:

f _(t)＝(t ₁-t)/t ₀

f _(t)It is the rate of change in latent period of current average waveform;

T is that because the phase waveform calculates once weekly, it gets the preclinical mean value of a plurality of waveforms that comprises in the current window when the inferior time value of hiding;

t ₀Being the maximal value of normal person's waking state and the variation in latent period of deep anaesthesia state, is the empirical data that clinical summary comes out;

t ₁Be the maximum duration of latent period delay behind normal person's deep anaesthesia state, just in the latent period of bringing out before waveform disappears, it is the empirical data of clinical summary;

If the average waveform length M is time 100mS, then comprise 4 waveforms in the average waveform, then;

T is 4 preclinical mean values of waveform in the window;

During employing method 1: t ₀Scope is: 20～60mS is best: 40mS

t ₁Scope is: 10～80mS is best: 50mS

During employing method 2: t ₀Scope is: 0～100mS is best: 50mS

t ₁Scope is: 50～150mS is best: 100mS

Like this by simultaneously to wave amplitude, the corrugated of the average waveform that obtains above long-pending and ripple latent period and before several times the reaction calculated value that brings out to carry out obtaining behind a series of related operation range of results be that 0～100 exponential quantity is come corresponding patient's to be measured various states, both guaranteed its visual result, easily handled, fully guaranteed its result's accuracy and reliability again, this also is one of emphasis of the present utility model.

Claims (3)

1, a kind of anesthesia monitoring device is characterized in that comprising:

The voice signal that is used to produce 35Hz～45Hz repetition frequency stimulates patient to be measured to detect the short tone burst stimulation signal generating source of ear and is used to produce continuous voice signal and with the white noise signal that shields another ear of patient to be measured the source takes place;

Be used to extract patient's to be measured auditory evoked potential (AEP) signal and to this auditory evoked potential (AEP) signal amplifies, filtering and analog to digital conversion (A/D) are handled low noise high precision physiological signal amplifier circuit device;

Be used to receive auditory evoked potential (AEP) signal through low noise high precision physiological signal amplifier circuit device, and this auditory evoked potential (AEP) signal by stages section carried out superposed average step by step and obtain the average waveform figure of each segment stable state auditory evoked potential signal, and according to latent period or the wave amplitude of the average waveform figure of each segment or the corrugated is long-pending or auditory steady-state evoked response (ASSR) exponential quantity of each segment is calculated in its combinatory analysis, and the data acquisition and the data analysis disposal system of the time dependent trend map of demonstration auditory steady-state evoked response (ASSR) exponential quantity.

2, anesthesia monitoring device according to claim 1 is characterized in that above-mentioned 35Hz～45Hz short tone burst stimulation signal generating source comprises:

Be used to produce the crystal oscillator of the sinusoidal wave digital voice signal of 200Hz～5KHz and time-frequency division produce circuit and prestore the standard sine wave signal can automatically controlled memory EEPROM or flash memory FLASH MEMORY system;

Be used for digital-to-analogue (D/A) change-over circuit that the sinusoidal wave digital voice signal through the 200Hz～5KHz frequency of crystal oscillator and time-frequency division circuit is carried out digital-to-analogue (D/A) conversion;

Be used for the sinusoidal wave voice signal through digital-to-analogue (D/A) change-over circuit is carried out regularly modulation and produces the timing modulation circuit of the tone burst voice signal of 35Hz～45Hz repetition frequency;

Be used for 35Hz～45Hz repetition frequency tone burst voice signal is carried out the audio power amplifier circuit of processing and amplifying;

The tone burst voice signal that is used for the 35Hz～45Hz repetition frequency that will handle through audio power amplifier circuit is transmitted to the earphone that patient to be measured detects ear.

3, anesthesia monitoring device according to claim 1 is characterized in that above-mentioned low noise high precision physiological signal amplifier circuit device comprises:

Near at least two electrodes in order to extraction auditory evoked potential signal of device patient's nervous centralis to be measured;

Be controlled by calibration and impedance measurement signal generation circuit and control signal latch cicuit in order to improve input impedance and the front buffer amplifying circuit of driving force with the shielding input channel is provided;

Be controlled by the control signal latch cicuit in order to suppress noise level, to improve the preposition differential amplifier circuit of gain;

Be controlled by the control signal latch cicuit in order to suppress the power frequency codan that power frequency is disturbed;

Be controlled by the low-pass filter circuit of control signal latch cicuit in order to the unnecessary high-frequency signal of filtering;

Be controlled by the control signal latch cicuit in order to signal is amplified to the programme-controlled gain amplifying circuit that is fit to carry out modulus (A/D) conversion;

Be controlled by the high-pass filtering circuit of control signal latch cicuit in order to the unnecessary low frequency signal of filtering;

Be controlled by the control signal latch cicuit in order to signal is sampled and analog-to-digital modulus (A/D) change-over circuit;

In order to receive under above-mentioned data acquisition and the data analysis system control signal that passes and translate into corresponding steering order, digital signal after controlling gain, the power frequency trap of amplification channel and extract the A/D conversion by the control signal latch cicuit and be uploaded to data acquisition and the single chip machine controlling circuit of data analysis system;

Realize the control signal latch cicuit that amplification channel is controlled in order to cooperate single chip machine controlling circuit;

Whether the gain in order to the self check amplification channel reaches normally with frequency band whether the detection potential electrode contacts good calibration and impedance measurement signal generation circuit in measuring process.

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