Defibrillator and method for charging defibrillation energy

Abstract

To provide a defibrillator that allows charging of defibrillation energy to a capacitor to be performed in as short a time as possible while suppressing an adverse effect on an electronic component receiving power supply from a battery even when a residual amount of the battery is reduced.SOLUTION: A defibrillator of the present invention includes: a battery; a capacitor for storing defibrillation energy; a control part for controlling charging to the capacitor by the battery; and a voltage measuring part for measuring the output voltage of the battery at the time of charging to the capacitor by the battery. The control part controls charging to the capacitor by the battery by dividing it at least into prior charging and subsequent additional charging. Further, the control part controls a charging speed at the time of additional charging on the basis of the output voltage of the battery measured by the voltage measuring part at the time of prior charging.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 switching circuit. 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 switching circuit. When the switching circuit is turned on, the defibrillation energy stored 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, in a defibrillator, a primary battery is used as the battery, and a large-capacity capacitor is used as the capacitor for storing defibrillation energy.

[0007] Therefore, when charging the capacitor with the battery, especially when the battery is in a depleted state (in other words, when the remaining battery level is low), the output voltage of the battery will drop significantly. In addition to the capacitor, electronic components such as a CPU (Central Processing Unit) are also connected to the battery, and the battery supplies voltage to these electronic components as well. Thus, if the output voltage of the battery drops too much during charging of the capacitor, the operation of the entire defibrillator may stop.

[0008] As one way to solve this problem, it is conceivable to estimate the remaining battery level and, based on the estimation result, control the output voltage or notify the user that the remaining battery level is low to prompt battery replacement. By the way, conventionally, the battery voltage in the no-load state has been measured and the remaining battery level has been estimated based on it. However, the estimated value of the remaining battery level based on this no-load state voltage does not match the actual remaining battery level. This is because the battery used in the defibrillator is a primary battery. Therefore, the conventional estimation of the remaining battery level is insufficient as a solution.

[0009] As another method, it is conceivable to suppress the decrease in the output voltage of the battery by limiting the current value from the battery during capacitor charging. However, if the current value is carelessly limited, the time required to charge the capacitor with the desired defibrillation energy will become long, which is not preferable. In particular, for patients with ventricular fibrillation and ventricular tachycardia, rapid treatment is necessary, so there is a desire to make the energy charging time of the capacitor as short as possible.

[0010] The present disclosure has been made in consideration of the above points, and provides a defibrillator and a method for charging defibrillation energy that can appropriately charge the capacitor according to the remaining battery level.

Means for Solving the Problem

[0011] One aspect of the defibrillator of the present disclosure is that a battery, a capacitor for storing defibrillation energy, a control unit for controlling charging of the capacitor by the battery, a voltage measurement unit for measuring the output voltage of the battery, and is provided with The control unit controls charging of the capacitor by the battery to be performed separately into at least pre-charging and subsequent additional charging, and further controls the charging speed during the additional charging based on the output voltage of the battery measured by the voltage measurement unit during the pre-charging.

[0012] One aspect of the defibrillation energy charging method of the present disclosure is a method for charging defibrillation energy in a defibrillator, including the step of pre-charging a capacitor with a battery, the step of additionally charging the capacitor with the battery after the pre-charging, the step of measuring the output voltage of the battery during the pre-charging, and the step of controlling the charging speed during the additional charging based on the measured output voltage. and includes

Advantages of the Invention

[0013] According to the present disclosure, it is possible to realize a defibrillator and a defibrillation energy charging method capable of appropriately charging a capacitor according to the remaining amount of the battery.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0015] First, before explaining the embodiment, the process leading to the present disclosure will be explained.

[0016] The inventor of the present disclosure has noticed that as a method of charging from the battery to the capacitor in a defibrillator, there is one that is performed in two stages: pre-charging and additional charging.

[0017] Pre-charging is performed immediately after the defibrillator is activated, and additional charging is performed after the connection with the patient is confirmed. By pre-charging a certain amount of defibrillation energy, the time from when it is determined that an electric shock is necessary until the energy charging is completed, that is, the time until the electric shock is executed, can be shortened.

[0018] The inventor of the present disclosure considered that if the output voltage of the battery is measured during pre-charging, the remaining amount of the battery can be accurately estimated compared to measuring the voltage of the battery in a no-load state. And based on the output voltage of the battery measured during pre-charging, by controlling the charging speed during additional charging, it is considered that additional charging with excessive voltage drop suppressed can be performed according to the remaining battery amount, and thus the present disclosure has been reached.

[0019] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings.

[0020] <1> Main Configuration of the Defibrillator FIG. 1 is a block diagram showing the main configuration of a defibrillator 100 according to the present 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.

[0021] 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 battery 111, a current control unit 114, a capacitor 115, an energization switch 116, and a voltage measurement unit 117.

[0022] The control unit 101 is constituted by a CPU (Central Processing Unit) or the like, and controls the operations of each part of the defibrillator 100.

[0023] The operation unit 102 includes a charge button, a shock button, etc. (not shown). Note that the shock button may be provided on the paddle if the discharge unit 200 is of the paddle type. When the shock button is operated, the charge stored in the capacitor 115 is output to the discharge unit 200.

[0024] 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.

[0025] The battery 111 is used to charge the capacitor 115 and generate defibrillation energy. Although not shown, the battery 111 is also connected to electronic components such as the control unit (CPU) 101 in addition to the capacitor 115, and the battery 111 supplies voltage to these electronic components.

[0026] In the example of this embodiment, the battery 111 is a lithium primary battery. Also, the battery 111 is a battery that is interchangeably mounted on the defibrillator 100 (that is, a replaceable battery), and is replaced with a newly fully charged battery, for example, every two years. Of course, the replacement timing of the battery 111 is not limited to this.

[0027] As the main battery 111, one with an output voltage of, for example, 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 battery 111 is 15 [V] in a state where no load is connected.

[0028] The voltage measurement unit 117 measures the output voltage of the battery 111. The voltage measurement unit 117 in this embodiment measures the output voltage of the battery 111 when the capacitor 115 is being charged by the battery 111, and outputs the measurement result to the control unit 101.

[0029] The control unit 101 controls the current control unit 114 based on the voltage measured by the voltage measurement unit 117. Thereby, the current value flowing from the battery 111 to the capacitor 115 is controlled based on the voltage measured by the voltage measurement unit 117. The current control unit 114 has a configuration having, for example, a switching element, and can control the current value by performing a switching operation based on the switching frequency from the control unit 101. This current control will be described in detail later.

[0030] 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 greater than a predetermined value and the shock button is operated, the control unit 101 turns on the energization switch 116 and outputs the charge stored in the capacitor 115 to the discharge unit 200.

[0031] <2>Operation of the Embodiment FIG. 2 is a flowchart for explaining the defibrillation energy charging operation in the defibrillator 100.

[0032] When the power supply of the defibrillator 100 is turned on in step S11, the capacitor 115 is pre-charged by the battery 111 in the subsequent step S12. When the defibrillator 100 recognizes the connection of the discharge unit 200 in step S13 (that is, when the control unit 101 recognizes that the discharge unit 200 is attached to the patient), the capacitor 115 is additionally charged by the battery 111 in step S14. Further, the defibrillator 100 analyzes the patient's ECG or the like in step S15.

[0033] When the charging is completed in step S16 and the analysis is completed in step S17, the defibrillator 100 executes an electric shock by turning on the energization switch 116 in step S18.

[0034] In the example of FIG. 2, the additional charging (step S14) and the analysis (step S15) are performed in parallel. However, for example, the analysis may be performed first, and when an analysis result indicating that an electric shock is necessary is obtained, the additional charging may be performed.

[0035] FIG. 3 is a diagram showing the state of the voltage when performing two-stage energy charging. FIG. 3A is a diagram showing the state of the output voltage of the battery 111, and FIG. 3B is a diagram showing the state of the voltage across the capacitor 115 (charging voltage). Here, it should be noted that the charging speed (the current flowing from the battery 111 to the capacitor 115) during pre-charging is set to be equal to or less than the charging speed during additional charging. Thereby, the voltage drop of the battery 111 during pre-charging does not adversely affect the operation of the entire defibrillator.

[0036] FIG. 4 is a flowchart showing in more detail the defibrillation energy charging operation by the defibrillator 100 of the present embodiment.

[0037] When the control unit 101 of the defibrillator 100 is powered on in step S31, in the subsequent step S32, it determines whether the output voltage (battery voltage) of the battery 111 measured by the voltage measurement unit 117 is equal to or higher than the reference voltage Vstdmin.

[0038] When the battery voltage is less than the reference value Vstdmin, the control unit 101 moves to step S34, skips the energy charging, and prompts battery replacement. Specifically, the control unit 101 causes the current control unit 114 to cut off the current, and outputs a display and / or voice prompting battery replacement from the display unit 103 and / or the voice output unit 104. On the other hand, when the battery voltage is equal to or higher than the reference value Vstdmin, the control unit 101 moves to step S33 and starts pre-charging. Specifically, the control unit 101 controls the current control unit 114 so that a current corresponding to the pre-charging flows. FIG. 5 is a diagram showing the operation transition with the reference value Vstdmin as a threshold.

[0039] Next, the control unit 101 selects the charging speed while performing step-by-step threshold determination. FIG. 6 is a diagram showing the magnitude relationship of a plurality of threshold values Vpremin, VpreL, VpreM, VpreH and the operation transition of the present embodiment using them.

[0040] In step S35, the control unit 101 determines whether the battery voltage is equal to or higher than the threshold value Vpremin. If it is less than the threshold value Vpremin, it moves to step S36 and aborts the energy charging.

[0041] When the battery voltage is equal to or higher than the threshold value Vpremin, the control unit 101 determines in step S37 whether the battery voltage is equal to or higher than the threshold value VpreL. If it is less than the threshold value VpreL, it moves to step S38, performs additional charging at a low speed, and outputs a battery remaining amount alarm (that is, notifies the user by display and / or voice that the remaining amount of the battery is decreasing).

[0042] When the battery voltage is equal to or higher than the threshold value VpreL, the control unit 101 determines whether the battery voltage is equal to or higher than the threshold value VpreM in step S39. If it is less than the threshold value VpreM, the process proceeds to step S40 to perform additional charging at a low speed.

[0043] When the battery voltage is equal to or higher than the threshold value VpreM, the control unit 101 determines whether the battery voltage is equal to or higher than the threshold value VpreH in step S41. If it is less than the threshold value VpreH, the process proceeds to step S42 to perform additional charging at a medium speed. On the other hand, if it is equal to or higher than the threshold value VpreH, the process proceeds to step S43 to perform additional charging at a high speed.

[0044] Here, low-speed charging can be achieved by reducing the current value of the current control unit 114, medium-speed charging can be achieved by setting the current value of the current control unit 114 to a medium level, and high-speed charging can be achieved by increasing the current value of the current control unit 114. That is, the control unit 101 controls the current value output from the battery 111 during additional charging based on the charging speed during additional charging.

[0045] In the case of the embodiment, the current flowing through the current control unit 114 is 1.0 [A] for low-speed charging, 1.5 [A] for medium-speed charging, and 2.0 [A] for high-speed charging. Also, in the case of the embodiment, the time required to store the desired defibrillation energy in the capacitor 115 is 20 seconds for low-speed charging, 15 seconds for medium-speed charging, and 10 seconds for high-speed charging. Note that in the embodiment, the charging speed is divided into three ranks: low speed, medium speed, and high speed. Of course, the charging speed is not limited to three ranks and may be two ranks or divided into four or more ranks.

[0046] <3>Summary As described above, the defibrillator 100 of the present embodiment divides the charging of the capacitor 115 by the battery 111 into at least pre-charging and subsequent additional charging. Further, the output voltage of the battery is measured during pre-charging, and the charging speed during additional charging is controlled based on the measured output voltage.

[0047] As a result, it is possible to realize a defibrillator 100 and a method for charging defibrillation energy that can appropriately charge the capacitor 115 in accordance with the remaining amount of the battery 111.

[0048] That is, according to the present embodiment, the remaining amount of the battery 111 can be accurately measured, and additional charging at a charging rate corresponding to the remaining battery amount is performed. Therefore, while keeping the voltage drop of the battery during additional charging within an allowable range, efficient additional charging can be performed. As a result, even when the remaining amount of the battery 111 decreases, it is possible to avoid the operation of the entire defibrillator 100 from stopping, and it is also possible to avoid the charging of defibrillation energy to the capacitor 115 from being unnecessarily prolonged.

[0049] According to the configuration of the above-described embodiment, since the pre-charging and the estimation of the remaining battery capacity are performed at once, there is no need to add a circuit for applying a load to the battery 111 separately for estimating the remaining battery amount.

[0050] Incidentally, if the capacitor 115 is charged at a constant charging rate (charging current) regardless of the remaining amount of the battery 111, a situation where "it takes time to charge even though the remaining amount of the battery 111 is sufficient" or a situation where "even if the current value is reduced (i.e., the charging rate is lowered), although there is a remaining amount sufficient to charge the energy, it is determined that the energy cannot be charged" may occur. According to the configuration of the present embodiment, such a situation can be avoided and appropriate defibrillation energy can be charged.

[0051] The above-described embodiments are merely examples of the implementation of the present invention, and the technical scope of the present invention should not be limitedly interpreted by these. That is, the present invention can be implemented in various forms without departing from the gist or the main features thereof.

[0052] In the above-described embodiment, an example in which the voltage measurement unit 117 is provided separately from the control unit 101 has been described. However, the voltage measurement unit 117 may be incorporated into the control unit 101. For example, when the control unit 101 is a CPU, voltage measurement may be performed using the functions of the CPU.

Industrial Applicability

[0053] 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

[0054] 100 Defibrillator 101 Control Unit 111 Battery 114 Current Control Unit 115 Capacitor 116 Energization Switch 117 Voltage Measurement Unit 200 Discharge Unit (Pad or Paddle)

Claims

1. A battery, a capacitor for storing defibrillation energy, a control unit for controlling charging of the capacitor by the battery, a voltage measurement unit for measuring the output voltage of the battery, comprising: The control unit: controls charging of the capacitor by the battery to be performed in at least a pre-charge and subsequent additional charging, and further controls the charging speed during the additional charging based on the output voltage of the battery measured by the voltage measurement unit during the pre-charge. A defibrillator.

2. The control unit decreases the charging speed during the additional charging as the output voltage of the battery measured by the voltage measurement unit during the pre-charge is lower. The defibrillator according to Claim 1.

3. The control unit controls the current value output from the battery during the additional charging based on the charging speed during the additional charging. The defibrillator according to Claim 1.

4. The current value flowing from the battery to the capacitor during the pre-charge is less than or equal to the current value flowing from the battery to the capacitor during the additional charging. The defibrillator according to Claim 1.

5. The battery is a primary battery. The defibrillator according to any one of Claims 1 to 4.

6. A method for charging defibrillation energy in a defibrillator, comprising: a step of pre-charging a capacitor with a battery, a step of additionally charging the capacitor with the battery after the pre-charge, a step of measuring the output voltage of the battery during the pre-charge, and a step of controlling the charging speed during the additional charging based on the measured output voltage. A method for charging defibrillation energy.

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