CN103301570A - Calibrating system and method of cardiac defibrillator analyzing instrument - Google Patents

Abstract

The present invention provides a calibration system and method for a cardiac defibrillator analyzer, which uses a voltage acquisition device to obtain the high-voltage pulse voltage output by the cardiac defibrillator, and calculates the output energy of the cardiac defibrillator according to the obtained voltage. Output energy to calibrate the energy measurement accuracy of the cardiac defibrillator analyzer to be calibrated, thereby avoiding the problem of inaccurate calibration of the cardiac defibrillator analyzer due to inaccurate reference energy obtained, thereby improving the accuracy of the calibration of the cardiac defibrillator analyzer Accuracy and reliability of cardiac defibrillator analyzer calibration.

Description

Cardiac defibrillator analyzer calibration system and method

technical field

The invention relates to the technical field of medical equipment, in particular to a calibration system and method for a cardiac defibrillator analyzer.

Background technique

Cardiac defibrillator is a medical electronic device that uses electric shock to rescue and treat patients with arrhythmia. It has the advantages of high curative effect, rapid action, easy operation and safety compared with drugs. The method of using a strong pulse current to pass through the heart to eliminate arrhythmia and restore sinus rhythm is called electric shock defibrillation. What acts on the heart is an instantaneous high-energy pulse, generally lasting 4ms to 10ms, and the energy is 40 joules. ~400 joules, therefore, the output energy of the cardiac defibrillator is very important for the rescue of the patient.

To this end, the country has issued the measurement and calibration specification "JJF1149-2006 Cardiac Defibrillator and Cardiac Defibrillator Calibration Specification", in which the main instrument used for cardiac defibrillator calibration is the Cardiac Defibrillator Analyzer, which passes the test of the heart The output energy of the defibrillator is used to calibrate the cardiac defibrillator. Regarding the cardiac defibrillator analyzer, the state has not promulgated corresponding verification regulations or calibration specifications. As a calibration device for the cardiac defibrillator analyzer, the energy traceability of the cardiac defibrillator has been plagued by various units.

The general calibration method that everyone adopts now is: use a cardiac defibrillator as the energy output source, a standard cardiac defibrillator analyzer as the standard, the tested cardiac defibrillator analyzer and the standard cardiac defibrillator analyzer Measure the same cardiac defibrillator, and compare the output energy of the cardiac defibrillator measured by the standard cardiac defibrillator analyzer and the cardiac defibrillator analyzer to calibrate the cardiac defibrillator analyzer . Specific steps are as follows:

First, set the energy output value on the cardiac defibrillator, connect the standard cardiac defibrillator analyzer to the output terminal of the cardiac defibrillator, the cardiac defibrillator outputs energy, and read the standard cardiac defibrillator analyzer Energy test value E1 (as shown in Figure 1a);

Next, keep the energy output value of the cardiac defibrillator unchanged, connect the analyzer of the cardiac defibrillator to be connected to the output end of the cardiac defibrillator, the output energy of the cardiac defibrillator, read the analyzer of the cardiac defibrillator The energy test value E2 (as shown in Figure 1b);

Finally, the analyzer of the cardiac defibrillator to be calibrated is calibrated by the difference between the energy test value E2 and the energy test value E1.

This method has the following disadvantages:

1. This method does not carry out normal value traceability, but compares the energy test value E2 with the energy test value E1;

2. After the output energy of the cardiac defibrillator reaches its set value, due to many reasons such as the internal discharge of the capacitor, the energy output value of the cardiac defibrillator has poor consistency under the same set value, resulting in the energy test value E2 An additional deviation from the energy test value E1 occurs.

Due to the above-mentioned deficiencies, the calibration of the cardiac defibrillator analyzer by the existing method is not accurate enough. Also, since the input of the cardiac defibrillator analyzer has an impedance of 50 ohms and has an ECG waveform output signal. Therefore, in order to eliminate the poor consistency of the output energy of the cardiac defibrillator, two cardiac defibrillator analyzers are connected to the cardiac defibrillator in parallel, and the output energy of the cardiac defibrillator is measured at the same time to measure the energy output of the cardiac defibrillator analyzer. Calibration of measurement accuracy is also not feasible.

Contents of the invention

The purpose of the present invention is to provide a cardiac defibrillator analyzer calibration system and method to solve the problem of inaccurate calibration of the energy measurement accuracy of the cardiac defibrillator analyzer in the prior art.

In order to solve the above-mentioned technical problems, the present invention provides a kind of cardiac defibrillator analyzer calibration system, comprising:

cardiac defibrillator;

A schooled cardiac defibrillator analyzer connected to the output of the cardiac defibrillator;

A voltage acquisition device connected to the output terminal of the cardiac defibrillator.

Optionally, in the cardiac defibrillator analyzer calibration system, the voltage acquisition device includes a high-voltage probe connected to the output end of the cardiac defibrillator, and an oscilloscope connected to the high-voltage probe.

Optionally, in the cardiac defibrillator analyzer calibration system, the oscilloscope is a digital real-time oscilloscope.

The present invention also provides a method for calibrating a cardiac defibrillator analyzer, comprising:

Set the output energy value of the cardiac defibrillator;

The tested cardiac defibrillator analyzer obtains the first output energy value of the cardiac defibrillator;

At the same time, the voltage of the cardiac defibrillator is obtained by using the voltage obtaining device, and the second output energy value of the cardiac defibrillator is obtained by using the following formula:

Wherein, R is the input terminal resistance of the cardiac defibrillator analyzer, Δt is the sampling time interval, and V(n) is the voltage measured at n moments;

The energy measurement accuracy of the tested cardiac defibrillator analyzer is calibrated by using the difference between the second output energy value and the first output energy value.

Optionally, in the method for calibrating a cardiac defibrillator analyzer, the voltage acquisition device includes a high-voltage probe and a digital real-time oscilloscope connected to the high-voltage probe.

Optionally, in the described cardiac defibrillator analyzer calibration method, before using the high-voltage probe and the oscilloscope connected with the high-voltage probe to obtain the voltage of the cardiac defibrillator, the high-voltage probe and the oscilloscope Carry out calibration to obtain the correction coefficients k ₁ and k ₂ ; at this time, the formula for obtaining the second output energy value is revised as:

Optionally, in the described cardiac defibrillator analyzer calibration method, under the same cardiac defibrillator energy setting value, repeat multiple measurements to obtain a plurality of first output energy values and A plurality of second output energy values simultaneously obtained from the first output energy value, using the difference between the average value of the plurality of second output energy values and the average value of the plurality of first output energy values to calibrate the cardiac defibrillator to be schooled The energy measurement accuracy of the analyzer.

In the cardiac defibrillator analyzer calibration system and method provided by the present invention, the high-voltage pulse voltage output by the cardiac defibrillator is obtained by using the voltage acquisition device, and the output energy of the cardiac defibrillator is calculated according to the obtained voltage, according to the Output energy to calibrate the energy measurement accuracy of the cardiac defibrillator analyzer to be calibrated, thereby avoiding the problem of inaccurate calibration of the cardiac defibrillator analyzer due to inaccurate reference energy obtained, thereby improving the accuracy of the calibration of the cardiac defibrillator analyzer Accuracy and reliability of cardiac defibrillator analyzer calibration.

Description of drawings

Figure 1a is a schematic diagram of a module of an existing standard cardiac defibrillator analyzer for measuring the output energy of a cardiac defibrillator;

Fig. 1b is a schematic diagram of the module for measuring the output energy of the cardiac defibrillator by the existing cardiac defibrillator analyzer;

Fig. 2 is the module schematic diagram of the cardiac defibrillator analyzer calibration system of the embodiment of the present invention;

Fig. 3 is a schematic flow chart of a method for calibrating a cardiac defibrillator analyzer according to an embodiment of the present invention.

Detailed ways

The cardiac defibrillator analyzer calibration system and method provided by the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Advantages and features of the present invention will be apparent from the following description and claims. It should be noted that all the drawings are in a very simplified form, and are only used for the purpose of conveniently and clearly assisting in describing the embodiments of the present invention.

Please refer to FIG. 2 , which is a block diagram of a calibration system for a cardiac defibrillator analyzer according to an embodiment of the present invention. As shown in Figure 2, the cardiac defibrillator analyzer calibration system includes:

Cardiac defibrillator 20;

The cardiac defibrillator analyzer 21 connected with the output end of the cardiac defibrillator 20;

A high voltage probe 22 connected to the output end of the cardiac defibrillator 20 , and a digital oscilloscope 23 connected to the high voltage probe 22 .

Here, the purpose of using the high-voltage probe 22 and the digital oscilloscope 23 is to obtain the voltage of the cardiac defibrillator 20, therefore, in other embodiments of the present invention, other voltage obtaining devices and the cardiac defibrillator can also be used. The output terminal of 20 is connected to obtain the voltage of the cardiac defibrillator 20, which is not limited in this application. In addition, in order to read the voltage conveniently, in this embodiment, a digital real-time oscilloscope 23 is used. In other embodiments of the present invention, other oscilloscopes, such as analog oscilloscopes, can also be used.

Correspondingly, this embodiment also provides a method for calibrating a cardiac defibrillator analyzer, please refer to FIG. 3 , which is a schematic flowchart of the method for calibrating a cardiac defibrillator analyzer according to an embodiment of the present invention. As shown in Figure 3, the calibration method of the cardiac defibrillator analyzer includes:

Step S30: setting the output energy value of the cardiac defibrillator;

Step S31: The analyzer of the cardiac defibrillator to be schooled obtains the first output energy value of the cardiac defibrillator;

Step S32: Using a voltage acquisition device to acquire the voltage of the cardiac defibrillator, and thus obtain a second output energy value of the cardiac defibrillator;

Step S33: Calibrate the energy measurement accuracy of the cardiac defibrillator analyzer to be tested by using the difference between the second output energy value and the first output energy value.

Wherein, after the voltage of the cardiac defibrillator is obtained by the voltage obtaining device, the second output energy value of the cardiac defibrillator is obtained by using the following formula 1:

(公式1)

(Formula 1)

Among them, R is the resistance of the input end of the cardiac defibrillator analyzer, Δt is the sampling time interval, and V(n) is the voltage measured at n time.

The principle that the energy of the cardiac defibrillator can be traced by using the above formula 1 is:

It is known that energy is the time integral of power, that is, energy and power p(t) can be expressed by the following formula 1.1:

Energy = ∫p(t)dt (Formula 1.1)

The power can be obtained through the voltage V and the input resistance R of the cardiac defibrillator analyzer, that is, it can be obtained by the following formula 1.2:

$p\left(t\right)=\frac{V{\left(t\right)}^2}{R}$ (Formula 1.2)

From formula 1.1 and formula 1.2, the following formula 1.3 can be further obtained:

(公式1.3)

(Formula 1.3)

And assuming that the sampling time interval of the voltage acquisition device (here being the high-voltage probe 22 and the digital oscilloscope 23 connected with the high-voltage probe 22) is short enough, then formula 1.3 can be transformed into formula 1:

(公式1)

(Formula 1)

Thus, the output voltage of the cardiac defibrillator is sampled by the voltage acquisition device, and then the accurate output energy value of the cardiac defibrillator can be obtained according to the above formula 1, that is, the energy of the defibrillator can be traced to the source.

In this embodiment, considering that the output voltage of the cardiac defibrillator 20 is a pulse voltage, and the maximum voltage amplitude will reach more than 5,000 volts, therefore, the high-voltage probe 22 is used as a high-voltage attenuator to divide the voltage of several thousand volts Voltage to several volts, and because the input impedance of the high-voltage probe 22 is high resistance, it has no influence on the circuit when it is connected, that is, the obtained voltage value is reliable. At the same time, the digital real-time oscilloscope 23 is used to sample the output voltage of the cardiac defibrillator, so that the voltage values at different times can be obtained more accurately.

In addition, in order to reduce the system error of the cardiac defibrillator analyzer calibration system, before utilizing the high-voltage probe 22 and the digital oscilloscope 23 connected with the high-voltage probe 22 to obtain the voltage of the cardiac defibrillator, first test the high-voltage probe 22 and the digital oscilloscope 23 to calibrate, specifically, calibrate the attenuation value of the high-voltage probe 22 to obtain a correction coefficient k ₁ , and calibrate the vertical scan of the digital oscilloscope 23 to obtain a correction coefficient k ₂ for vertical voltage measurement, therefore , after taking into account the above correction coefficient, the formula 1 also correspondingly becomes the following formula 2:

(公式2)

(Formula 2)

Wherein, V (n) is the voltage value obtained by the measurement of the digital oscilloscope 23 at n moments, k ₁ is the attenuation value correction coefficient of the high voltage probe 22, k ₂ is the vertical voltage measurement correction coefficient of the digital oscilloscope 23, and Δt is the sampling time interval of the oscilloscope, R is the actual input resistance value of the analyzer of the cardiac defibrillator being schooled. Usually, the nominal value of the resistance of the input terminal of the analyzed cardiac defibrillator is 50 ohms. In order to ensure the accuracy of the resistance value of the input terminal, it can be measured by a digital multimeter to obtain the accurate value of the resistance.

Through the above method, the energy value of the cardiac defibrillator can be traced, that is, the second energy value, and then the energy measurement of the cardiac defibrillator analyzer to be calibrated can be calibrated by the difference between the second output energy value and the first output energy value Accuracy. At the same time, in order to ensure the reliability of the calibration, multiple measurements can be repeated under the same set value of the cardiac defibrillator to obtain multiple first output energy values and multiple output energy values obtained simultaneously with the multiple first output energy values. a second output energy value, and use the difference between the average value of the multiple second output energy values and the average value of the multiple first output energy values to calibrate the energy measurement accuracy of the cardiac defibrillator analyzer to be calibrated.

According to the above-mentioned cardiac defibrillator analyzer calibration system and method, it is assumed that a GE Cardioserv cardiac defibrillator is used as an energy output source, and its maximum output energy is 360 joules.

The oscilloscope high-voltage probe P6015A from Tektronix is used as a voltage attenuator with an input impedance of 100MΩ, a bandwidth of 75MHz, an attenuation value of 1000:1, and a maximum test voltage of 20kV DC/40kV peak value (100ms pulse width). In order to ensure the accuracy of the measurement results, the attenuation value has been calibrated to obtain its accurate attenuation value (ie, the correction coefficient k1).

The digital oscilloscope TDS3052 produced by Tektronix is used as the voltage acquisition device. Its input impedance is set to high resistance 1MΩ, the magnification is set to 1000 times (consistent with the magnification of P6015A), the oscilloscope trigger is set to normal trigger, and the trigger voltage is set. Flat, set the scan time as 5ms/div, and set the vertical scan as 1V/div. In order to improve the accuracy of the measurement results, the vertical scale of the oscilloscope has been calibrated with an oscilloscope calibrator, and its vertical scale error (ie, the correction coefficient k ₂ ) has been obtained.

Under different energy setting values of the cardiac defibrillator, the energy measurement accuracy of the cardiac defibrillator analyzer is calibrated, and in order to ensure the reliability of the calibration, at each energy setting value of the cardiac defibrillator Repeat the measurement three times to obtain three first output energy values and three second output energy values, and calibrate by the difference between the average value of the three second output energy values and the average value of the three first output energy values The energy measurement accuracy of the tested cardiac defibrillator analyzer. Thus, the following table 1 is obtained:

Table 1

Here, in the case that the set value of the cardiac defibrillator is 50 joules (that is, the output energy value of the cardiac defibrillator is set to be 50 joules), for the calibration of the energy measurement accuracy of the cardiac defibrillator analyzer, it is Calibrate according to the difference between (50.8+51.4+51.1)/3 (the average value of the second output energy value) and (50.2+50.9+50.7)/3 (the average value of the first output energy value). Similarly, the defibrillator analyzer can be accurately calibrated when the defibrillator is set to 100 joules, 200 joules and 360 joules. Since the second output energy value is an energy traceable value for the cardiac defibrillator, the calibration of the cardiac defibrillator analyzer according to the second output energy value can ensure the accuracy and reliability of the calibration.

The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention. Any changes and modifications made by those of ordinary skill in the field of the present invention based on the above disclosures shall fall within the protection scope of the claims.

Claims (7)

1. A cardiac defibrillator analyzer calibration system, characterized in that, comprising: cardiac defibrillator; A schooled cardiac defibrillator analyzer connected to the output of the cardiac defibrillator; A voltage acquisition device connected to the output terminal of the cardiac defibrillator. 2. cardiac defibrillator analyzer calibration system as claimed in claim 1, is characterized in that, described voltage acquisition device comprises the high voltage probe that is connected with the output end of described cardiac defibrillator, and is connected with described high voltage probe oscilloscope. 3. The cardiac defibrillator analyzer calibration system as claimed in claim 2, wherein the oscilloscope is a digital real-time oscilloscope. 4. A method for calibrating a cardiac defibrillator analyzer, comprising: Set the output energy value of the cardiac defibrillator; The tested cardiac defibrillator analyzer obtains the first output energy value of the cardiac defibrillator; At the same time, the voltage of the cardiac defibrillator is obtained by using the voltage obtaining device, and the second output energy value of the cardiac defibrillator is obtained by using the following formula: Wherein, R is the input terminal resistance of the cardiac defibrillator analyzer, Δt is the sampling time interval, and V(n) is the voltage measured at n moments; The energy measurement accuracy of the tested cardiac defibrillator analyzer is calibrated by using the difference between the second output energy value and the first output energy value. 5. the cardiac defibrillator analyzer calibration method as claimed in claim 4, is characterized in that, described voltage obtaining device comprises high-voltage probe and the digital real-time oscilloscope that is connected with described high-voltage probe. 6. cardiac defibrillator analyzer calibration method as claimed in claim 5, is characterized in that, before utilizing high-voltage probe and the oscilloscope connected with described high-voltage probe to obtain the voltage of described cardiac defibrillator, first to described The high-voltage probe and oscilloscope are calibrated to obtain the correction coefficients k ₁ and k ₂ ; at this time, the formula for obtaining the second output energy value is corrected as:

7. the cardiac defibrillator analyzer calibration method described in any one of 6 in claim 4, it is characterized in that, under the same cardiac defibrillator energy setting value, repeat multiple measurements, obtain multiple The first output energy value and the multiple second output energy values obtained simultaneously with the multiple first output energy values, using the average value of the multiple second output energy values and the average value of the multiple first output energy values The difference is used to calibrate the energy measurement accuracy of the defibrillator analyzer under test.

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