Method and device for defibrillation

Abstract

A method and a device for defibrillation. When a shock is generated, energy is transmitted from the low-voltage range to a high-voltage range, at least one current surge being generated in the low-voltage range, stepped up to the high-voltage range and guided to electrodes. An energy supply, power electronics and an energy storage device are used in the low-voltage range.

Claims

1. A device for defibrillation, which has a low-voltage side with a low-voltage range of 40 V to 400 V and a high-voltage side with a high-voltage range of 2000 V to 2500 V, comprising: at least one translator that couples the low-voltage range to the high-voltage, range, the translator having a primary part and a secondary part; electrodes arranged in the high-voltage range; a power supply, a set of power electronics, and an energy store arranged in the low-voltage range, the energy store being configured to provide an amount of energy of about 200 WS to generate a high voltage peak of about 2000 V; and a voltage converter for converting a current surge from the low-voltage range into the high-voltage range, wherein the voltage converter is a resonance converter, wherein the translator is part of the voltage converter.

2. The device according to claim 1, wherein the device is operative to generate a high voltage temporarily and on demand.

3. The device according to claim 1, further comprising a processor arranged on the low-voltage side to control the device.

4. The device according to claim 1, wherein the energy store includes at least one of the group consisting of a capacitor, a super-capacitor, an accumulator, and a battery.

5. The device according to claim 1, wherein the energy store is configured to store energy so that the device is able to generate a shock instantaneously after being switched on.

6. The device according to claim 1, wherein the at least one translator has at least one primary and/or secondary winding.

7. The device according to claim 6, wherein at least two primary and/or secondary windings of the at least one translator are combined by a series and/or a parallel circuit.

8. The device according to claim 7, wherein the secondary windings of the at least one translator are interconnected in series so that electronic components with a maximum voltage breakdown strength specified in a range from about 500 V to about 1500 V are useable on the high-voltage side.

9. The device according to claim 1, wherein the device is configured to generate both a monophasic and a biphasic output pulse.

10. The device according to claim 1, further comprising an element to measure a current and/or voltage on the primary part or the secondary part of the at least one transfer element.

11. A method for defibrillation, comprising the steps of: translating energy from a low-voltage range into a high-voltage range; and, in the high-voltage range, generating at least one current surge and guiding the current surge to electrodes, wherein the method includes using a device according to claim 1 to carry out the steps.

12. The method according to claim 11, including controlling the generation of the current surge in the high-voltage range with a processor arranged in the low-voltage range.

13. The method according to claim 11, including the steps of: a. providing energy required for the current surge in the high-voltage range by an energy store in the low-voltage range; b. controlling a voltage converter having at least one translator by a processor arranged in the low-voltage range so that a high-voltage signal or the current surge is generated on the high-voltage side; c. controlling a phase of the high-voltage signal or current surge so that either a monophasic or a biphasic high-voltage signal or a monophasic or biphasic current surge is generated; and d. delivering the high-voltage signal or current surge via the electrodes to a patient for implementing a shock function or a pacemaker function.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Different exemplary embodiments and designs of the invention are shown in the following figures. Shown are:

(2) FIG. 1: a block circuit diagram as a schematic representation of the physical structure of a device according to the invention for defibrillation,

(3) FIG. 2: a detailed block diagram to illustrate a design variant of a device according to the invention for defibrillation,

(4) FIG. 3: timing diagrams to illustrate the functional sequence,

(5) FIG. 4: a schematic representation of the structure of the charge regulator circuit of the storage capacitor,

(6) FIG. 5: a schematic representation of the circuit design of a push-pull converter and a transformer for translating the shock energy from the low-voltage range into the high-voltage range,

(7) FIG. 6: a schematic representation of a measurement point for current and voltage,

(8) FIG. 7: a circuit diagram of an embodiment according to the invention of a multi-level translator,

(9) FIG. 8: three schematic block circuit diagrams for various topologies according to the invention of a resonance converter,

(10) FIG. 9: a circuit diagram of a resonant circuit according to the invention with translator and rectifier, and

(11) FIG. 10: a circuit diagram of a synchronous rectifier based on the example of a translator with a resonant circuit.

DETAILED DESCRIPTION OF THE INVENTION

(12) FIG. 1 shows a block circuit diagram of a device according to the invention for defibrillation (1), and in particular illustrates the coupling of the low-voltage region to the high-voltage region by means of a translator (13). In the low-voltage region a power supply (10) and an energy store (12) are arranged together with the power electronics (11).

(13) In the high-voltage region the phase controller (14) and two electrodes (16, 17) are arranged. Optionally, a device for current and/or voltage measurement (15) can be arranged in the high-voltage range.

(14) FIG. 2 shows the layout of the overall system of an embodiment according to the invention of a device for defibrillation (1) in an overview drawing. Illustrated in particular is the electronic part of the apparatus for defibrillation (1) with which the defibrillation pulse can be generated.

(15) The input signals E1, E2 and E3 of this so-called Deficore are provided by the energy supply (E1), which in an advantageous embodiment of the invention has a voltage of approximately 12 V at an available power of approximately 50 W to 100 W, the signal for activating a shock (E2), and a configuration signal (E3), which can be transmitted via an I2C interface, for example.

(16) With the Deficore the defibrillation pulse can be delivered to a patient via the electrodes of the patient connector. The patient connector comprises the terminals apex (A1) and sternum (A2).

(17) Using a device according to the invention for defibrillation (1), in an advantageous embodiment the energy store (12) can be used to deliver an energy of approximately 200 Ws and to generate a high-voltage pulse of approximately 2,000 V. The energy that can be stored using the energy store (12) is composed of at least the deliverable energy and the energy needed to compensate for the losses occurring within the device according to the invention for defibrillation.

(18) In particular, it is envisaged to generate a biphasic shock with a length of roughly 10 ms. The intensity of the shock current is typically up to 20 Amperes.

(19) According to one embodiment of the device according to the invention for defibrillation (1) and/or a method according to the invention for defibrillation, a user can choose whether the shock current is to be generated in a biphasic or monophasic form, and the shock length that should be generated.

(20) In accordance with the diagrams in FIG. 3 the function of generating a biphasic shock will be explained again in detail by means of an example.

(21) FIG. 3.1 shows the voltage waveform UC1 on the capacitor C1 as a function of time t, FIG. 3.2 shows the current waveform I.sub.DC2 at the output of the voltage converter DC2 (21) as a function of time t and FIG. 3.3 shows the current waveform I.sub.OUT at the output of the device for the defibrillation (1) as a function of time t.

(22) In the case of a function that starts at time t0 all voltages are initially set to 0 V and all currents to 0 Amperes. On switching on the supply voltage of the device for defibrillation (1), the charge regulator (18) is started and begins to charge the energy store (12) in the form of capacitor C1 with the injected current.

(23) At time t1 the energy store (12) is fully charged and the voltage level on the capacitor C1 is approximately 150 V. The required voltage level on the energy store (12) depends on the energy to be delivered. The charging of the energy store (12) is carried out adaptively and typically to a voltage of up to approximately 200 V.

(24) In a further step, the processor (19) shown in FIG. 2 then triggers the shock at time t2 and a pulse-width modulation is applied to the voltage converter DC2 (21). In addition, the phase controller (14) implemented as an H-bridge is then enabled.

(25) In a further method step, the processor (19) regulates the current of the shock by modulation of the pulse widths and/or the frequency and/or the phase angle of the control signals for the power electronics. To do so, via the voltage converter DC2 (21), the capacitor voltage is transformed by means of the translator (13) up to the required potential of up to approximately 2,500 V on the high-voltage side. At the output of DC2 and at the output of the H-bridge, a current I.sub.DC2 and I.sub.OUT with a current intensity corresponding to I.sub.Actual are produced.

(26) In a subsequent step at time t2a, the current I.sub.DC2 at the output of the DC2 is briefly reduced to 0 Amperes, causing the H-bridge to switch over in order to generate a biphasic pulse.

(27) The currents I.sub.DC2 and I.sub.OUT then increase back up to the current I.sub.Actual before they are reduced to 0 Amperes again at time t3a, and the generation of a shock pulse is completed.

(28) During the generation of the shock with the current waveform I.sub.OUT the energy store (12) discharges and the voltage across the capacitor C1 falls according to FIG. 3.1 between the times t2 and t3 to a residual voltage of roughly 50 V. The residual voltage depends on the required shock energy and the dimensions of the translator (13).

(29) In accordance with a further method step, the current values and voltage values required for the control scheme are measured in front of the voltage converter DC2 (21). In general, these measurements can also take place behind the voltage converter DC2 (21). In the second case, however, a potential isolation is applied between the processor (19) and the measuring point (20).

(30) The drawing of FIG. 4 illustrates details of the charge regulator (18) and the energy store implemented as a capacitor C1 (12).

(31) In the region of the capacitor C1 the energy required for the shock plus the energy required to compensate for the losses is stored, and the charge regulator (18), implemented as a DC-DC converter, charges the capacitor C1. During the charging of the capacitor C1 the input current is preferably limited.

(32) To implement the charge regulator (18) a flyback topology is preferably chosen, in order to generate a high voltage difference between input and output.

(33) For the capacitor C1 a commercially available electrolytic capacitor can be used, for example, but other types of capacitor such as super-capacitors or ceramic capacitors are also conceivable.

(34) In the case of an example energy of 200 Ws to be stored in the capacitor C1, at a specified applied voltage of approximately 150 V in the fully charged condition and a specified applied voltage of approximately 50 V after the discharge by the energy output in generating a shock, a capacitor C1 with a capacity of approximately 10 mF is required. The corresponding formulae are shown in FIG. 4 without taking into account the losses occurring.

(35) In the drawing in FIG. 5, further details of the voltage converter DC2 (21) and the translator (13) are illustrated.

(36) The voltage converter DC2 (21) transfers the shock energy from the low-voltage side to the high-voltage side using the transformer (13). The voltage converter DC2 (21) can be implemented as a push-pull converter, for example.

(37) On the low-voltage side of the voltage converter DC2 (21) a full-bridge circuit with power transistors is implemented. The power transistors are each driven using a pulse-width modulated signal (PWM 1 H/L, PWM 2 H/L), so that the direction of the current flow through the at least one primary-side winding of the at least one transformer (13) can be controlled.

(38) On the secondary side of the transformer (13) a bridge rectifier implemented with diodes, which is followed by an L-C filter, is connected downstream of the winding. At the terminal HV out, therefore, a DC voltage signal in the high-voltage range can be tapped off.

(39) A power of, for example, 20 kW for a period of 10 ms is output to deliver an energy of 200 Ws.

(40) In a preferred embodiment of the invention the voltage converter DC2 (21) can be controlled directly by the processor (19) or by the processor (19) in conjunction with gate drivers.

(41) The translator (13) designed as a step-up transformer can be implemented, for example, in planar technology. In addition, it is also conceivable to connect a plurality of transformers in parallel with each other, and thus to implement the voltage converter DC2 (21) as a multi-parallel push-pull converter. It is also possible to use transformers with multiple secondary windings and/or multiple transformers with one or more secondary windings in one embodiment according to the invention of a device for defibrillation (1).

(42) According to the design variant shown in FIG. 5, a typical high-voltage range from approximately 2,000 V to 2,500 V is implemented. Here, also, the high voltage is preferably generated exclusively during the delivery of the shock. For a power output of typically 200 Ws and a patient resistance of 25 to 175 Ohms (typically 50 Ohms), a voltage of 750 V to 2 kV is required.

(43) In the drawing of FIG. 6, further details of the current and voltage measurement are illustrated.

(44) The discharge current from the capacitors can be measured and the corresponding value provided for the regulation.

(45) The measurement can be carried out continuously or on a sampled basis. A typical sampling frequency is in the range of 20 to 40 kHz. This equates to approximately 200 to 400 measurements per shock duration.

(46) According to a preferred embodiment variant, the current and voltage are measured behind the voltage converter DC2 (21) and in front of the H-bridge on the high-voltage side.

(47) FIG. 7 shows a schematic representation of a circuit diagram of an exemplary multi-level design of the translator (13) according to the invention followed by a rectifier circuit. The voltage applied on the primary side Uin (input voltage of the H-bridge of the inverter), can be transformed via the translator (13) into a high-voltage range and converted using rectifiers into the output voltage Uout. On the primary side the translator (13) has a winding (T: Prim), while on the secondary side two windings (T: SEK) connected in series are arranged. The translator (13) has an exemplary winding ratio of 1:8.

(48) A bridge rectifier implemented using diodes, and a capacitor (C1, C2) and an H-bridge are connected downstream of each of the secondary-side windings (T: SEK) of the translator (13). Across each of the series-connected secondary-side circuit branches, therefore, only half of the output voltage Uout is dropped. According to the invention, the semiconductors and capacitors on the secondary side therefore require only half the voltage breakdown strength.

(49) FIG. 8 shows three topologies according to the invention of a resonance converter for transforming the shock energy from the low-voltage range into the high-voltage range.

(50) FIG. 8.1 shows an arrangement of the resonant circuit between the H-bridge of the inverter and the primary side of the translator (13) in the low-voltage range.

(51) FIG. 8.2 shows an arrangement of the resonant circuit on the secondary side of the translator (13) before the rectifier.

(52) FIG. 8.3 shows a combined arrangement of the resonant circuit on the primary and secondary side of the translator (13).

(53) FIG. 9 shows a circuit diagram of a resonant circuit according to the invention with a transformer. The resonant circuit is implemented as a combined topology on the primary and secondary side of the translator (13).

(54) The voltage DCin (input voltage of the inverter in the low-voltage range) can be converted into the output voltage HVout using the components shown.

(55) The relevant components for setting the desired operating point (resonant frequency) of the resonant circuit or the resonant converter are the stray inductance T: LR of the transformer or translator (13), and the secondary-side capacitor C.sub.9.2 (resonance capacitor). In an advantageous embodiment of the device according to the invention the values of the primary magnetizing inductance T: LM of the translator (13) and of the capacitor C.sub.9.1, which is used for DC suppression in the translator (13), are dimensioned in such a way that the desired operating point of the resonant circuit is not changed. This is usually solved by positioning an additionally resulting resonance frequency as far away as possible from the frequency of the operating point.

(56) The rectifier implemented using diodes has a filter connected downstream, which is provided by the components L.sub.9 and C.sub.9.3.

(57) FIG. 10 shows a circuit diagram of a switchable rectifier, implemented as a synchronous rectifier, based on the example of a translator (13) with a resonant circuit.

(58) The input voltage U.sub.IN can be converted into the output voltage U.sub.OUT using the components shown.

(59) The secondary-side rectifier has the switches S1 and S2, wherein the rectifier function can be implemented by means of an active and synchronous control of the switches S1 and S2.

(60) Depending on the switching sequence of S1 and S2, a positive or negative voltage U.sub.OUT can be generated. The switches S1 and S2 must be embodied as semiconductors that can be closed and opened bidirectionally.