JPS585056B2 - Fetal heart rate automatic analysis device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention belongs to the field of childbirth monitoring devices for recording and monitoring physiological phenomena related to human childbirth and providing basic data for diagnosis to doctors.

In particular, this invention measures and records fetal heart rate and pregnant woman's uterine contraction pressure, and compares and determines specific parameters calculated from these data with preset parameter settings, thereby providing information to doctors. Regarding the improvement of a labor monitoring device configured to display an alarm, each of two or more parameters is weighted (hereinafter referred to as weight) based on the academic experience of a doctor.

), then for parameters with values exceeding the parameter setting values, weights are imposed and calculation processing is performed according to a specific evaluation function based on clinical medical empirical rules. The purpose is to provide equipment.

FIG. 1 is a block diagram showing the basic configuration of a conventional birth monitoring device of this type, in which 1 is a heart rate detection unit consisting of a microphone etc. that is closely held around the abdomen of an expectant and nursing mother, and 2 is a block diagram showing the basic configuration of a conventional birth monitoring device of this type. A uterine contractile pressure detecting section consisting of a strain gauge or the like held tightly around the abdomen; 3 a record display section consisting of a pen recorder, etc.; the input terminal thereof receives the outputs of the heart rate detecting section 1 and the uterine contractile pressure detecting section 2; connected to the respective terminals.

4 is a data processing unit for detecting various parameters as basic data for diagnosis and further performing judgment processing,
The input terminals are respectively connected to a heart rate signal output terminal 3a and a uterine contraction pressure signal output terminal 3b of the record display section 3.

3c and 3d are the recording paper and recording paper feed mechanism of the recording display section 3, respectively, and 3e and 3f are pens.

Now, when the heart rate detecting section 1 and the uterine contraction pressure detecting section 2 are closely attached to the abdomen during pregnancy and childbirth, the heart rate detecting section 1 receives an analog voltage as a heart rate signal proportional to the fetal heart rate, and The uterine contraction pressure detection unit 2 supplies analog voltages as uterine contraction pressure signals proportional to the uterine contraction pressure of pregnant and nursing mothers to the recording and display unit 3, respectively.

In response to these analog voltages, the recording display unit 3 operates as a normal pen recorder, and changes the heart rate recording pen 3e and the uterine contraction pressure recording pen 3f in proportion to the heart rate and uterine contraction pressure, respectively. let

The recording paper 3c is fed out by the recording paper foot mechanism 3d and moves over time while sliding on the pens 3e and 3f, so that changes in heart rate and uterine contraction pressure over time are recorded as a continuous curve on the recording paper 3c. Is displayed.

At this time, the record/display unit 3 also supplies analog voltages as the heart rate signal and the uterine contraction pressure signal to the data processing unit 4 through the heart rate signal output terminal 3a and the uterine contraction pressure signal output terminal 3b.

The data processing unit 4 receives both signals, compares them with set values fixedly set in advance, and displays an alarm.

In this way, the childbirth monitoring device automatically presents basic data to the doctor for diagnosing the abnormality or normality of physiological phenomena related to childbirth.

However, in conventional labor monitoring devices, the set values are fixed, and the doctor's judgment cannot be transmitted to the device during the signal processing process.

In other words, it is not possible to involve doctors' judgments regarding various factors in the signal processing of judgment information, such as individual differences between expectant mothers and the effects of the disease if the expectant mother has complications. Therefore, the obtained judgment information was not comparable to a doctor's diagnosis that took the above-mentioned factors into consideration, but was merely a presentation of reference material for the doctor's diagnosis.

In order to overcome the above-mentioned limitations imposed on conventional childbirth monitoring devices, this invention provides the following:
For each parameter that characterizes temporal fluctuations consisting of short-term fluctuations and long-term fluctuations regarding the fetal heart rate signal waveform and the pregnant woman's uterine contractile pressure signal waveform, weights are variably set based on a doctor's judgment, and a value exceeding the parameter setting value is set. The present invention provides an automatic fetal heart rate analysis device configured to involve a doctor's judgment in the calculation process of comprehensive judgment information by performing calculation processing on a parameter having a weight.

FIG. 2 is a block diagram showing a more detailed configuration of the data processing section 4 of the fetal heart rate automatic analysis device which is an embodiment of the present invention, and 4a is an analog-digital conversion section, which has one input terminal. is connected to the heart rate signal output terminal 3a of the record display section 3, and the other input terminal is connected to the uterine contraction pressure signal output terminal 3b of the record display section 3.

4b is a data storage section consisting of a RAM etc.; 4c is a parameter calculation processing section consisting of a digital arithmetic circuit etc.; and 4d.
1 is a parameter determination section consisting of a digital comparison logic circuit, etc., and is connected to a parameter variable setting section 4e consisting of a digital sign setting switch, etc.

Reference numeral 4f denotes a score calculation section consisting of a digital addition circuit, etc., and is connected to a weight variable setting section 4g consisting of a digital sign setting switch.

Reference numeral 4h denotes a total score determining section comprising a digital comparison logic circuit, etc., and is connected to a total score variable setting section 4i comprising a digital code setting switch and the like.

4j is an alarm display section consisting of a buzzer, indicator light, etc.

FIGS. 3A and 3B show examples of time-varying waveforms of a heart rate signal and a uterine contraction pressure signal, respectively.

Now, from the heart rate signal output terminal 3a and uterine contraction pressure signal output terminal 3b of the record display section 3 in FIG. 1, the heart rate signal and uterine contraction pressure signal as shown in FIGS.
When supplied to the analog-digital converter 4a in the figure, the analog-digital converter 4a extracts these waveforms at a sampling period of about 0.5 seconds and converts them into digital codes corresponding to the instantaneous peak values. Then, it is transferred to the data storage section 4b.

The uterine contraction pressure signal is a signal that is output instantaneously in response to the uterine contraction pressure, but its fluctuation over time is gradual, and the heart rate signal is calculated from the heartbeat interval for each heartbeat. Therefore, by extracting with a sampling period of about 0.5 seconds, it is possible to sufficiently reproduce the fluctuation information of these signal waveforms.

In many cases, the heart rate signal ranges from 0 BPM to 250 BPM, and the uterine contraction pressure signal ranges from 0 mmHg to 100 BPM.
Each mHg range is normalized to correspond to an analog voltage of 0 to 1.25V.

Now, for a specific measurement period, the data storage unit 4b organizes and stores each digital code corresponding to each peak value extracted from the waveform in the order in which they were extracted, and also stores these digital codes in accordance with the stored order. , are sequentially read out during the measurement period at the same time intervals as the sampling period and transferred to the parameter calculation processing section 4c.

At this time, since the data storage section 4b is composed of a RAM or the like, the stored contents will not be destroyed even if the stored digital codes are read and transferred, and the digital codes extracted during the measurement period will not be destroyed. is held in memory during that period and is successively updated with digital codes representing the waveforms to be newly stored.

The parameter calculation processing unit 4c processes the digital code groups successively transferred from the data storage unit 4b, and calculates short-term fluctuations and long-term fluctuations in the heart rate signal and uterine contraction pressure signal reproduced by these code groups. We calculate various parameters that characterize the changes over time.

Representative examples of these parameters will be explained below with reference to FIG.

In the figure, ala is the baseline, for example 6
These are the most frequently occurring levels of the heart rate signal and uterine contraction pressure signal during the processing period set to 1 minute, that is, the past 6 minutes.

b is the amplitude between the lower pole of the heart rate signal waveform and base life 8, and is called the heart rate signal amplitude.

C is the time from the uppermost point of the uterine contraction pressure signal waveform to the lowermost point of the heart rate signal waveform, and is called a delay time.

d is the time from the lower pole of the heart rate signal waveform to the point where the signal waveform intersects the baseline a, and is called the recovery time.

e is the time from the point where the heart rate signal waveform is falling and crossing the baseline a to the point where the signal waveform is rising and crossing the baseline a, and is called the bradycardia period.

f is the area occupied by the heart rate signal waveform in the time-amplitude plane during the bradycardia period, and is called area.

Among these parameters, heart rate signal amplitude b, delay time c, recovery time d, and bradycardia period e are instantaneous processing parameters calculated every time the bradycardia period appears, and the heart rate signal and uterine contraction pressure are This is a parameter that characterizes short-term fluctuations in signals.

On the other hand, baseline a and area f are periodic processing parameters calculated for a processing period of 6 minutes in the past from the processing time and a measurement period set at 6-minute intervals from the start of the device, respectively. is a parameter that characterizes the long-term fluctuation of the uterine contraction pressure signal.

Returning to FIG. 2, the parameter calculation processing section 4c calculates the instantaneous processing parameters each time the bradycardia period is detected, and transfers digital codes representing the values of the respective parameters to the parameter determination section 4d.

The parameter determination unit 4d includes a parameter variable installation unit 4e.
, the parameters a~ set in advance by the doctor
Since the digital codes representing the parameter setting values regarding f are continuously supplied, the parameter determination unit 4d reads the digital codes representing the setting values corresponding to each of the instantaneous processing parameters b to e from among these setting values. and compare the magnitude relationship with each instantaneous processing parameter.

At this time, a value calculated for the past 6 minutes of processing period from the processing time is used as the baseline a.

Now, as shown in FIG. 3, if the parameter setting value for the heart rate signal amplitude is bo, the parameter determination section 4d calculates and determines that the value of this parameter b exceeds the parameter setting value b0. , outputs a parameter determination signal for parameter b to the score calculation unit 4f.

Further, if the parameter setting value is b0', the parameter determination section 4d does not output a parameter determination signal for parameter b.

In exactly the same way, for parameters c to e, each parameter has a corresponding parameter setting value c0.
When the calculation unit determines that the value exceeds ~e0, the parameter determination unit 4d outputs a parameter determination signal for the parameter that exceeds the set value.

Therefore, in the example waveform shown in FIG. 3, the parameters b, c, and e have their respective set values b0. Since the value exceeds c0°e0, parameter determination signals are output for these parameters, but since the parameter d does not exceed the set value d0, no parameter determination signal is output.

Upon receiving such a parameter determination signal, the score calculation unit 4f performs calculation processing on the parameter determination signal in order to obtain comprehensive determination information.

That is, for each parameter determination signal, a variably set weight is added to that parameter.

The weight for each parameter is set in advance by the doctor operating the digital setting switch of the variable weight setting section 4g, and a digital code representing the weight for each parameter is continuously supplied to the score calculation section 4f. Therefore, the score calculation unit 4f reads each weight corresponding to each parameter determination signal supplied from the parameter determination unit 4d, and adds these weights.

Returning to the example shown in FIG. 3, for example, if weights as shown in Table B are set for each instantaneous processing parameter shown in Table 1A, then the parameter determination unit 4d
Since the parameter determination signal outputted by is as shown in Table C, the total weight of the instantaneous processing parameters is 3+8+0+4=15, as shown in the table.

Such arithmetic processing, judgment, and score calculation of instantaneous processing parameters are executed every time a bradycardia period is detected, and the sum of the weights of instantaneous processing parameters is calculated for the measurement period set at 6-minute intervals from the start of the device. The accumulated values are accumulated, and at the end of the measurement period, a digital code representing the accumulated value is transferred to the total score determination section 4h.

At this time, the weights of the periodic processing parameters simultaneously transferred to the total score determination section 4h will be explained below.

The parameter calculation processing unit 4c detects the end point of the measurement period, calculates the most frequently occurring level of the heart rate signal for that measurement period, that is, the baseline, and calculates the bradycardia period detected during this measurement period. The total area for each area is calculated, and digital codes representing these values are transferred to the parameter determination unit 4d.

Since the parameter determination unit 4d receives the periodic processing parameter setting values as well as the instantaneous processing parameter setting values from the parameter variable setting unit 4e, it reads these and calculates the baseline and area totals during the measurement period, respectively. Compare and judge the periodic processing parameter settings corresponding to the
The parameter determination signal is supplied to the score calculation section 4f.

According to the example shown in FIG. 3, a0' is the baseline upper limit setting value, a0' is the baseline lower limit setting value, and since the baseline is within the range of both membrane constant values, the parameter judgment signal for the baseline is Out.

I don't feel strong.

Although only partially shown in the figure, the area f0
The cumulative value (Σf0) for the measurement period of area f is the area setting value, and the cumulative value (Σf) for the measurement period of area f
If it is assumed that is larger than (Σf0), a parameter determination signal for the area is supplied to the score calculation unit 4f.

The score calculating section 4f reads the weight of the periodic processing parameter set in the digital setting switch of the variable weight setting section 4g in exactly the same way as the instantaneous processing parameter setting value, and corresponds to the parameter judgment signal supplied from the parameter judgment section 4d. A digital code representing a total score obtained by adding the weights of the respective periodic processing parameters and adding the added value to the added value of the weights of the instantaneous processing parameters described above is supplied to the total score determining section 4h.

The total score determining section 4h receives the digital code and compares it with the digital code representing the variable limit value of the total score supplied from the total score variable setting section 4i.

The total score variable setting section 41 sets the variable limit value set by the doctor in advance by operating a digital setting switch, that is,
A digital code representing a value corresponding to the upper limit or lower limit of the total score is continuously supplied to the total score determining section 4h.

When the total score determination unit 4h determines that the total score for the measurement period supplied from the score calculation unit 4f exceeds the variable limit value of the total score supplied from the total score variable setting unit 4i, it displays an alarm signal. The signal is supplied to the section 44j to sound the buzzer and light up the indicator light.

Such an alarm display allows the doctor to obtain comprehensive judgment information that can be directly linked to diagnosis.

At this time, even if only the parameter judgment signal corresponding to any one parameter is supplied to the score calculation section 4f, a total score exceeding the maximum variable limit value that can be set by the total score variable setting section 41 is calculated. It is preferable that the weight variable setting section 4g is configured so that the important weight can also be set.

In this way, by setting an important weight for one parameter, when the value of that parameter exceeds the parameter setting value set corresponding to that parameter, the value of the other parameter will not change and will always be applied. Since a warning signal is obtained when the total score exceeds the variable limit value 11, there is a practical benefit in that it is possible to easily determine the magnitude relationship with the parameter setting value for only one parameter.

Such judgment for each parameter is extremely convenient when used to align the optimal weight values for each parameter so that the comprehensive judgment information based on the total score best matches the clinical medical diagnosis. It is.

Furthermore, the parameter variable setting section 4e in this embodiment,
The variable weight setting section 4g and the variable total score setting section 41 are configured to set parameter setting values, weights, and variable limit values of the total score using digital quantities by operating digital setting switches. It is also included in the parameter variable setting means 4e, weight variable setting means 4g, and total score variable setting means 41 described in this specification to set various variable setting values in analog quantities by operating potentiometers or the like. .

As described above, the present invention calculates various parameters that characterize changes over time in fetal heart rate and pregnant woman's uterine contraction pressure, and compares the magnitude relationship between each parameter and the parameter setting value corresponding to each parameter. Judgment is made, adding the weight corresponding to the parameter that exceeds the parameter setting value,
A total score is calculated, the magnitude relationship between the total score and the variable limit value of the score is compared and judged, and an alarm signal is output based on the comparison and judgment result, and furthermore, the above-mentioned parameter setting value, weight, and variable limit value of the total score are determined. According to the present invention, when monitoring the state of childbirth by determining changes over time in the fetal heart rate and uterine contraction pressure, the heart rate, The criterion for discrimination based on the amount of change over time characterized by various instantaneous processing parameters and periodic processing parameters regarding the contraction pressure can be arbitrarily changed.

Moreover, in the configuration of the present invention, not only the parameter setting value for each parameter, but also the weight for each parameter and the sum of the weights for parameters whose values exceed the parameter setting value, that is, the variable limit value for the total score are also determined.

Since these can be independently and variably set, changes in the aforementioned discrimination criteria are extremely diverse and widespread, and due to factors such as individual differences among expectant and nursing mothers and complications, fetal heart rate, Even if there is a large variation in the trend of fluctuations in contraction pressure over time, it is possible to address each factor and accurately determine the fluctuations in fetal heart rate and uterine contraction pressure over time that should issue an alarm signal. .

In this way, the doctor's judgment can be involved in the process of determining the state of childbirth based on the temporal fluctuations in fetal heart rate and uterine contractile pressure. According to the present invention, the parameter setting values are fixedly set. Unlike the alarm signals in conventional devices of this type, the total score is not limited to reference data for diagnosis, but is automatically presented as judgment information directly connected to diagnosis, thereby achieving accurate diagnosis. Therefore, the industrial benefits of this invention are enormous.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of a conventional labor monitoring device, FIG. 2 is a block diagram showing the configuration of a data processing section of an automatic fetal heart rate analyzer that is an example of the present invention, and FIG. FIG. 3 is a waveform diagram showing temporal fluctuations of a signal and a uterine contraction pressure signal. 1... Heart rate detection unit, 2... Uterine contraction pressure detection unit, 3... Record display unit, 4...
Data processing section, 4a...Analog-digital conversion section, 4b...Data storage section, 4c...
...Parameter calculation processing section, 4d...Parameter judgment section, 4e...Parameter variable setting section, 4
f...score calculation section, 4g...variable weight setting section, 4h...total score judgment section, 41...total score variable setting section, 4j.
...Alarm display section.

Claims (1)

[Claims] 1. Heart rate detection means 1 that detects the heart rate of a fetus and outputs a heart rate signal corresponding to the heart rate, and a uterine contraction that detects labor pains of an expectant mother and corresponds to the uterine contraction pressure. A uterine contraction pressure detection means 2 that outputs a pressure signal, and instantaneous processing parameters including heart rate signal amplitude b, delay time c, recovery time d, and bradycardia period e that characterize short-term fluctuations of the heart rate signal and the uterine contraction pressure signal. and a parameter calculation processing means 4c that calculates periodic processing parameters including a baseline a and an area f that characterize the long-term fluctuations of the heart rate signal and the uterine contraction pressure signal, and instantaneous processing parameters calculated by the parameter calculation processing means 4c, Parameter variable setting means 4e for variably setting parameter setting values corresponding to the upper limit value or lower limit value for each of the periodic processing parameters, and parameter calculation processing means 4
The instantaneous processing parameters and periodic processing parameters calculated by c are compared with the parameter setting values variably set for each of the instantaneous processing parameters and periodic processing parameters by the parameter variable setting means 4e, and the instantaneous processing parameters, a parameter determining means 4d for outputting a parameter determination signal corresponding to the parameter when determining that each value of the periodic processing parameter exceeds a parameter setting value that is variably set corresponding to the parameter; Variable weight setting means 4g that variably sets weights corresponding to each of the instantaneous processing parameters and periodic processing parameters, and variable weight setting means 4g for variably setting the weights corresponding to each of the instantaneous processing parameters and periodic processing parameters; A score calculating means 4f that calculates a total score by adding weights variably set by the setting means 4g, and a variable total score that variably sets a variable limit value corresponding to an upper limit or a lower limit for the total score calculated by the score calculating means 4f. Setting means 4i and score calculation means 4f
compares and determines the magnitude relationship between the total score calculated by the total score and the variable limit value variably set by the total score variable setting means 4i, and outputs an alarm display signal when it is determined that the total score exceeds the variable limit value. An automatic fetal heart rate analysis device comprising a total score determining means 4h. 2 Weights such that the total score calculated for any one of the instantaneous processing parameters and periodic processing parameters exceeds the maximum variable limit value that can be variably set by the total score variable setting means 4i.
2. The fetal heartbeat automatic analysis device according to claim 1, further comprising variable weight setting means 4g which is capable of setting important weights for each of instantaneous processing parameters and periodic processing parameters.