Defibrillator and method for charging defibrillation energy

Abstract

To provide a defibrillator capable of performing defibrillation at appropriate timing and with appropriate energy.SOLUTION: A defibrillator of the present invention includes: a first battery; a second battery; a capacitor for storing defibrillation energy; a voltage measuring part for measuring the voltage of the first battery when the capacitor is charged using the first battery; and a control part for controlling whether the second battery is to be used for charging the capacitor on the basis of the voltage measured by the voltage measuring part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a defibrillator and a method for charging defibrillation energy.

Background Art

[0002] Conventionally, as a device for treating ventricular fibrillation (Vf), a defibrillator has been widely used. As a typical defibrillator, an automated external defibrillator (AED) is well known. The defibrillator treats ventricular fibrillation or pulseless VT by discharging a high-voltage pulse to the heart of a patient in whom ventricular fibrillation or pulseless VT has occurred.

[0003] Such a defibrillator has a battery, a capacitor, and a power switch. Before defibrillation, the capacitor is charged by the battery. The capacitor is electrically connected to a discharge unit such as electrode pads or paddles via the power switch. When the power switch is turned on, the defibrillation energy accumulated in the capacitor is discharged to the heart of the patient via the discharge unit.

[0004] This type of defibrillator is described in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, when the battery is depleted (in other words, when the remaining amount of the battery decreases), the following problems occur. First, there is a problem that the time required to charge the capacitor with the desired energy becomes long. Second, there is a possibility that the capacitor may not be charged with sufficient energy.

[0007] As a result, when the battery is depleted, there is a risk that defibrillation cannot be performed at an appropriate timing and with appropriate energy. In particular, for patients with ventricular fibrillation and ventricular tachycardia, since prompt treatment is required, it is necessary to charge the capacitor with energy at high speed. Therefore, the above first problem is an absolutely avoidable problem.

[0008] The present disclosure has been made in consideration of the above points, and provides a defibrillator capable of performing defibrillation at an appropriate timing and with appropriate energy, and a method for charging defibrillation energy.

Means for Solving the Problems

[0009] One aspect of the defibrillator of the present disclosure is a first battery, a second battery, a capacitor for storing defibrillation energy, a voltage measurement unit that measures the voltage of the first battery when charging the capacitor using the first battery, a control unit that controls whether to use the second battery for charging the capacitor based on the voltage measured by the voltage measurement unit, and includes.

[0010] One aspect of the method for charging defibrillation energy of the present disclosure is a method for charging defibrillation energy in a defibrillator, a step of charging a capacitor with a first battery, a step of measuring the output voltage of the first battery during charging of the capacitor by the first battery, Based on the output voltage of the measured first battery, controlling whether to charge the capacitor using a second battery; including.

Advantages of the Invention

[0011] According to the present disclosure, a defibrillator capable of performing defibrillation at appropriate timing and with appropriate energy, and a method for charging defibrillation energy are provided.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0014] <1> Main configuration of the defibrillator FIG. 1 is a block diagram showing the main configuration of a defibrillator 100 according to this embodiment. The defibrillator 100 is a so-called external defibrillator or an AED. A discharge unit 200, which is an electrode pad or paddle that contacts a patient, is connected to the defibrillator 100.

[0015] The defibrillator 100 includes a control unit 101, an operation unit 102, a display unit 103, an audio output unit 104, and an ECG (electrocardiogram) processing unit 105. The defibrillator 100 also includes a main battery 111, a sub-battery 112, a booster circuit 113, a connection switching unit 114, a capacitor 115, an energization switch 116, and a voltage measurement unit 117.

[0016] The control unit 101 is configured by a CPU (Central Processing Unit) or the like, and controls the operation of each part of the defibrillator 100.

[0017] The operation unit 102 includes a charge button, a shock button, etc. (not shown). The shock button may be provided on the paddle if the discharge unit 200 is of the paddle type. When the charge button is operated, charging of the capacitor 115 is started, and when the shock button is operated, the charge stored in the capacitor 115 is output to the discharge unit 200.

[0018] In addition, the defibrillator 100 can also perform electrocardiogram analysis based on the electrocardiogram acquired by the ECG processing unit 105 by the control unit 101, and determine the necessity of defibrillation and the like.

[0019] The main battery 111 is provided to charge the capacitor 115 and generate defibrillation energy. The sub-battery 112 is mainly used as a power source other than defibrillation energy for components such as the RTC (Real Time Clock) unit 121.

[0020] In the example of this embodiment, the main battery 111 and the sub-battery 112 are each a lithium primary battery. Also, in the example of this embodiment, the battery capacities of the main battery 111 and the sub-battery 112 are equal. However, the output voltage of the main battery 111 is greater than the output voltage of the sub-battery 112.

[0021] The main battery 111 is a battery that is replaceably mounted on the defibrillator 100 (i.e., a replaceable battery), and is replaced, for example, with a newly fully charged battery every two years. On the other hand, the sub-battery 112 is a battery that is non-replaceably attached to the defibrillator 100 (i.e., a built-in battery). The main battery 111 has a battery capacity that can charge the capacitor 115 about 200 times. The sub-battery 112 has a battery capacity that can operate the internal circuits of the defibrillator 100, such as the RTC unit 121, for about 10 years.

[0022] As the main battery 111, one with an output voltage of 12 to 18 [V] in a state where no load (capacitor 115) is connected is used. In the example of this embodiment, the output voltage of the main battery 111 is 15 [V] in a state where no load is connected. As the sub-battery 112, one with an output voltage of 2 to 5 [V] in a state where no load is connected is used. In the example of this embodiment, the output voltage of the sub-battery 112 is 3 [V] in a state where no load is connected. The boost circuit 113 boosts the input 3 [V] voltage from the sub-battery 112 to about 15 [V] and outputs it.

[0023] The voltage measurement unit 117 measures the output voltage of the main battery 111 when the capacitor 115 is being charged by the main battery 111. The voltage information measured by the voltage measurement unit 117 is output to the control unit 101.

[0024] Based on the voltage measured by the voltage measurement unit 117, the control unit 101 controls which battery, the main battery 111 or the sub - battery 112, is used to charge the capacitor 115. Specifically, the control unit 101 outputs a control signal to the connection switching unit 114 to control whether only the main battery 111 is connected to the capacitor 115 or both the main battery 111 and the sub - battery 112 are connected to the capacitor 115. The connection switching unit 114 is composed of, for example, a power path control IC, a boost circuit that boosts the battery voltage, and an energy output module, etc.

[0025] In the case of this embodiment, the control unit 101 determines a threshold value using the output voltage of the main battery 111 measured by the voltage measurement unit 117. Then, when the output voltage of the main battery 111 is equal to or higher than the threshold value, the control unit 101 connects the capacitor 115 and the main battery 111 and charges the capacitor 115 using the main battery 111. On the other hand, when the output voltage of the main battery 111 is lower than the threshold value, the control unit 101 connects both the main battery 111 and the sub - battery 112 to the capacitor 115 and charges the capacitor 115 using both the main battery 111 and the sub - battery 112.

[0026] Also, the control unit 101 calculates the defibrillation energy stored in the capacitor 115 based on the voltage across the high - voltage capacitor that constitutes the capacitor 115. When the defibrillation energy is equal to or higher than a predetermined value and the shock button is operated, the control unit 101 turns on the energization switch 116 to output the charge stored in the capacitor 115 to the discharge unit 200.

[0027] <2>Operation of the Embodiment FIG. 2 is a flowchart for explaining the defibrillation energy charging operation in the defibrillator 100.

[0028] When the charging button is operated by the user, the defibrillator 100 starts charging the defibrillation energy in step S11. At this time, the control unit 101 controls the connection switching unit 114 to connect the main battery 111 and the capacitor 115, whereby the capacitor 115 is charged by the main battery 111.

[0029] In the subsequent step S12, the voltage of the main battery 111 is measured by the voltage measurement unit 117. In the subsequent step S13, the control unit 101 compares the measured voltage with a threshold value to perform a threshold determination.

[0030] When the measured voltage is equal to or higher than the threshold value (step S13; NO), the defibrillator 100 moves to step S14 and charges the capacitor 115 without using the sub-battery 112. In other words, the capacitor 115 is charged only by the main battery 111.

[0031] On the other hand, when the measured voltage is less than the threshold value (step S13; YES), the defibrillator 100 moves to step S15 and charges the capacitor 115 using the voltage of the sub-battery 112 boosted by the boost circuit 113. At this time, the main battery 111 may also be used for charging together, or the capacitor 115 may be charged only by the sub-battery 112. In the case of the present embodiment, the capacitor 115 is charged using the main battery 111 together.

[0032] In the subsequent step S16, the control unit 101 determines whether the defibrillation energy is sufficiently charged based on the voltage across the capacitor 115. When the defibrillator 100 determines that the capacitor 115 is charged with sufficient defibrillation energy (step S16; YES), it proceeds to step S17 and ends the charging of the defibrillation energy to the capacitor 115. On the other hand, when the defibrillator 100 determines that the capacitor 115 is not charged with sufficient defibrillation energy (step S16; NO), it returns to step S12 and continues the charging.

[0033] FIG. 3 is a diagram showing changes in voltage, current, and defibrillation energy during defibrillation energy charging of the defibrillator 100 according to the present embodiment.

[0034] FIG. 3A is a diagram showing the output voltage of the main battery 111, FIG. 3B is a diagram showing the output current of the main battery 111, FIG. 3C is a diagram showing the output voltage of the sub-battery 112, FIG. 3D is a diagram showing the output current of the sub-battery 112, and FIG. 3E is a diagram showing the voltage across the capacitor 115 (i.e., corresponding to the defibrillation energy stored in the capacitor 115).

[0035] The defibrillator 100 starts charging the defibrillation energy by connecting the main battery 111 to the capacitor 115 at time t1. Then, the output voltage of the main battery 111 rapidly decreases.

[0036] Here, since the primary battery has a high output impedance, when a primary battery is used as the main battery 111 as in the embodiment and a large load such as the capacitor 115 of the defibrillator 100 is connected to the output side thereof, a rapid voltage drop occurs. As described above, this voltage drop increases as the main battery 111 is depleted.

[0037] When the defibrillator 100 detects that the voltage of the main battery 111 is less than the threshold value at time t2, it starts assistance by the sub-battery 112 at the subsequent time t3. In the example of FIG. 3, the threshold value is 10 [V].

[0038] From time t3 to time t4, the defibrillator 100 supplies the voltage of the boosted sub-battery 112 to the capacitor 115 in addition to the voltage of the main battery 111 to charge the capacitor 115. In the example of the present embodiment, the boost circuit 113 boosts the output voltage of the sub-battery 112 to 10 [V] and supplies it to the capacitor 115. Actually, the output voltages of the main battery 111 and the sub-battery 112 are further boosted by a boost circuit (not shown) of the connection switching unit 114 and supplied to the capacitor 115.

[0039] By doing so, even when the main battery 111 is depleted (i.e., the remaining battery level is insufficient) and the output voltage drops significantly during charging of the capacitor 115, the defibrillator 100 of the present embodiment can avoid situations where the time required to charge the defibrillation energy becomes long or the required amount of defibrillation energy cannot be charged, by assisting the main battery 111 with the sub-battery 112.

[0040] <3> Comparative Example Here, as a comparative example to the embodiment, the operation of a conventional defibrillator that charges the defibrillation energy only with the main battery 111 without assisting the charging of the defibrillation energy by the sub-battery 112 will be described.

[0041] Figure 4 shows an example where the remaining battery level of the main battery 111 is sufficient. Figure 4A is a diagram showing the output voltage of the main battery 111, Figure 4B is a diagram showing the output current of the main battery 111, and Figure 4C is a diagram showing the voltage across the capacitor 115 (i.e., corresponding to the defibrillation energy stored in the capacitor 115).

[0042] When the main battery 111 is connected to the capacitor 115 at time t1 to start charging the defibrillation energy, the output voltage of the main battery 111 decreases. However, since the remaining battery level is sufficient, the amount of decrease is small. In the example of Fig. 4A, the voltage of the main battery 111 during charging is 12 [V], which is a voltage that can charge the capacitor 115 within a predetermined time. Therefore, the time required to charge the defibrillation energy (the time from the start of charging to the end of charging) is the specified time (10 [sec]) and does not become longer.

[0043] On the other hand, problems occur when the remaining battery level of the main battery 111 is insufficient. Fig. 5 shows an example in which the time required to charge the defibrillation energy becomes longer, and Fig. 6 shows an example in which the desired defibrillation energy cannot be charged.

[0044] First, the example of Fig. 5 will be described. In Fig. 5, the solid line shows the operation during battery consumption. For comparison, the dashed-dotted line shows the operation in the steady state (i.e., the state when the battery is not consumed). Fig. 5A is a diagram showing the output voltage of the main battery 111, Fig. 5B is a diagram showing the output current of the main battery 111, and Fig. 5C is a diagram showing the voltage across the capacitor 115 (i.e., corresponding to the defibrillation energy stored in the capacitor 115).

[0045] When the charging of defibrillation energy is started by connecting the main battery 111 to the capacitor 115 at time t1, the output voltage of the main battery 111 will drop rapidly. In particular, in the example of FIG. 5, since the main battery 111 is depleted, the output voltage drops significantly. If the output voltage of the main battery 111 drops too much, the operations of other parts (e.g., the CPU) supplied with voltage by the main battery 111 will stop. Therefore, a process of limiting the output current of the main battery 111 is performed to prevent this. As shown in FIG. 5B, in this example, the output current is limited from 3 [A] to 2 [A]. As a result, the rate of charge accumulation in the capacitor 115 decreases, and as shown in FIG. 5C, the time required to charge the defibrillation energy becomes longer. In the embodiment, the charging time of the defibrillation energy was 10 [sec], but in this example, it becomes 20 [sec].

[0046] Next, the example of FIG. 6 will be described. In FIG. 6, the solid line indicates the operation during battery depletion. For comparison, the dashed-dotted line indicates the operation in the steady state (i.e., the state when the battery is not depleted). FIG. 6A is a diagram showing the output voltage of the main battery 111, FIG. 6B is a diagram showing the output current of the main battery 111, and FIG. 6C is a diagram showing the voltage across the capacitor 115 (i.e., corresponding to the defibrillation energy stored in the capacitor 115).

[0047] When the charging of the defibrillation energy is started by connecting the main battery 111 to the capacitor 115 at time t1, the output voltage of the main battery 111 will drop rapidly. In particular, in the example of FIG. 6, since the main battery 111 is depleted, the output voltage will drop significantly. As described with reference to FIG. 5, if the current is limited, the drop in the output voltage can be suppressed, but if the current is not limited, the output voltage will drop significantly. In the example of FIG. 6A, the output voltage has dropped to 5.5 [V] at time t10. As a result, the operation of other parts (for example, the CPU) to which the main battery 111 supplies voltage stops (so-called "momentary power failure" occurs), and the operation of the defibrillator stops. Therefore, as shown in FIG. 6C, the capacitor cannot be charged with the desired defibrillation energy.

[0048] <4>Summary As described above, the defibrillator 100 of the present embodiment includes a first battery (main battery 111), a second battery (sub-battery 112), a capacitor 115 that stores defibrillation energy, a voltage measurement unit 117 that measures the voltage of the first battery when charging the capacitor 115 using the first battery, and a control unit 101 that controls whether to use the second battery for charging the capacitor 115 based on the voltage measured by the voltage measurement unit 117.

[0049] Thereby, when the first battery is depleted, the second battery is used to charge the capacitor 115. Therefore, even when the first battery is depleted, it is possible to avoid the charging of the defibrillation energy taking a long time and not being able to charge sufficient defibrillation energy. Thus, a defibrillator 100 capable of performing defibrillation at an appropriate timing and with appropriate energy can be realized.

[0050] In addition, since the capacitor 115 is charged by the second battery only when the first battery is depleted, depletion of the second battery can be suppressed. Therefore, when the second battery (sub-battery 112) is a built-in (i.e., non-replaceable) battery as in the embodiment, unnecessary depletion of the second battery (sub-battery 112) can be suppressed, and shortening of the product life of the defibrillator 100 can be suppressed.

[0051] Also, the defibrillator 100 may be placed not only indoors but also outdoors. In such a case, when the temperature is low, the voltage drop of the main battery 111 becomes significant. Therefore, charging of the defibrillation energy is greatly affected not only by the depletion of the main battery 111 but also by the external environment.

[0052] Even in such a case, in the defibrillator 100 of the present embodiment, when the output voltage of the main battery 111 becomes less than a predetermined value, the output voltage of the sub-battery 112 is boosted and supplied to the capacitor 115 to charge the defibrillation energy. Therefore, it is possible to avoid the charging of the defibrillation energy taking a long time and not being able to charge sufficient defibrillation energy.

[0053] The above-described embodiments merely show an example of concretization in implementing the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. That is, the present invention can be implemented in various forms without departing from the gist or its main features.

[0054] In the above-described embodiment, the case where the output voltage of the main battery 111 is determined by a threshold value has been described. However, the present invention is not limited to this. The slope of the output voltage of the main battery 111 may be measured, and when the slope becomes steeper than a predetermined value, it may be determined that the main battery 111 is depleted, and the sub-battery 112 may be used. By doing so, charging by the sub-battery 112 can be started before the output voltage of the main battery 111 drops below a predetermined value, so that the charging time can be further shortened.

Industrial Applicability

[0055] The defibrillator and the method for charging defibrillation energy of the present disclosure are applicable to a defibrillator that charges a capacitor with defibrillation energy using a battery.

Explanation of Signs

[0056] 100 Defibrillator 101 Control unit 111 Main battery 112 Sub-battery 113 Boost circuit 114 Connection switching unit 115 Capacitor 116 Energization switch 117 Voltage measurement unit 200 Discharge unit (pad or paddle)

Claims

1. a first battery; a second battery; a capacitor for storing defibrillation energy; a voltage measurement unit that measures the voltage of the first battery when charging the capacitor using the first battery; a control unit that controls whether to use the second battery to charge the capacitor based on the voltage measured by the voltage measurement unit; A defibrillator comprising the above.

2. The voltage of the second battery is lower than the voltage of the first battery, A boost circuit is provided between the second battery and the capacitor, The voltage of the second battery is supplied to the capacitor via the boost circuit, The defibrillator according to claim 1.

3. The control unit performs threshold determination on the measured voltage of the first battery using a predetermined threshold value, and controls to charge the capacitor using the second battery when the voltage is less than the threshold value. The defibrillator according to claim 1.

4. When the steepness of the drop in the measured voltage of the first battery is greater than a predetermined threshold value, the control unit controls to charge the capacitor using the second battery. The defibrillator according to claim 1.

5. The first battery and the second battery are primary batteries. The defibrillator according to any one of claims 1 to 4.

6. The first battery is a replaceable battery, and the second battery is a built-in battery. The defibrillator according to any one of claims 1 to 4.

7. A method for charging defibrillation energy in a defibrillator, comprising: charging a capacitor with a first battery; measuring the output voltage of the first battery during charging of the capacitor by the first battery; controlling whether to charge the capacitor using a second battery based on the measured output voltage of the first battery. A method for charging defibrillation energy including the above steps.

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