Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
  • A61N1/372—Arrangements in connection with the implantation of stimulators
  • A61N1/378—Electrical supply
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/38—Applying electric currents by contact electrodes alternating or intermittent currents for producing shock effects
  • A61N1/39—Heart defibrillators
  • A61N1/3904—External heart defibrillators [EHD]
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
  • A61N1/00—Electrotherapy; Circuits therefor
  • A61N1/18—Applying electric currents by contact electrodes
  • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
  • A61N1/38—Applying electric currents by contact electrodes alternating or intermittent currents for producing shock effects
  • A61N1/39—Heart defibrillators
  • A61N1/3975—Power supply

Definitions

• This invention relates to medical devices and particularly to powering medical devices with electrical energy converted from mechanical energy.
• Conventional electrical medical devices receive their electrical energy from either a direct power line or from a battery.
• Such medical devices include cardiac defibrillators, electrocardiographs (stationary recorders and ambulatory
• cardiac defibrillator which discharges electrical energy into a patient to restore a normal rhythmic heartbeat.
• the normal rhythmic heartbeat can be disrupted for several reasons. For example, cardiac arrest occurs when there is a sudden cessation of a heartbeat, or when there is a loss of effective pumping of blood by the heart.
• cardiac arrest is caused by arrhythmias, which abruptly cease circulation throughout the body and vital organs. Without rapid resuscitation, victims of cardiac arrest become permanently injured or die.
• arrhythmias are caused by disturban'es in the electrical conduction mechanism of the heart.
• Defibrillation is the process of restoring the heart to its normal rhythmic heartbeat.
• defibrillator operator such as a physician, paramedic or other emergency care personnel, administers one or more electric charges or shocks to the patient using a defibrillator.
• Defibrillators are either implantable, meaning the device operates in vivo, or external, meaning the device acts from outside the body.
• Cardiac defibrillators include circuitry, a capacitor, and a power source.
• the power source for conventional defibrillators is either an AC power source (e.g., from an electric power line) or a battery.
• the circuitry of the conventional defibrillator passes electrical energy from the power source to the capacitor. Then when the defibrillator operator instructs the defibrillator to deliver the shock, the stored charge of the capacitor is discharged into a patient to provide a therapeutic shock.
• FIGURE 1 shows the general arrangement of a conventional defibrillator 10.
• Conventional defibrillator 10 includes a battery 20, a control unit 30, a charging circuit 40, a capacitor 50, a patient interface 60, and a printer 70.
• Battery 20 supplies electrical energy to control unit 30 and to capacitor 50 through charging circuit 40. If battery 20 is rechargeable, defibrillator 10 typically also includes an external battery charger 25.
• Control unit 30 controls the operation of defibrillator 10.
• control unit 30 signals capacitor 50 to pass the stored charge to the patient through patient interface 60.
• Control unit 30 may also include a display (not shown) for the defibrillator operator to view (such as a conventionally known ⁇ •acklit LCD or the like).
• Charging circuit 40 transfers the electrical energy from battery 20 to capacitor 50.
• charging circuits include a power conditioning circuit (not shown), which receives power from battery 20, and a transformer or rectifier circuit (not shown) coupled to the conditioning circuit and intermediate the power conditioning circuit and capacitor 50.
• Charging circuit 40 increases the voltage supplied from the battery 20 and outputs the increased voltage to the capacitor 50.
• Capacitor 50 holds the charge until it is delivered or discharged into a patient through patient interface 60.
• Capacitor 50 and control unit 30 are electrically coupled to patient interface 60.
• Patient interface 60 usually includes either pads or paddles (not shown) that are placed in physical contact with the patient by the defibrillator operator.
• the paddles may range in size according to the expected use (e.g., pediatric to adult patients) and preferably include charge/shock and printer buttons.
• the paddles may range in size from approximately 17 cm 2 (or smaller) to approximately 80 cm 2 in area (or larger).
• the pads include an adapter cable for adult and pediatric pads. When pads are used, the buttons for charge/shock and printer are located elsewhere on the defibrillator (e.g., on control unit 30).
• Printer 70 is electrically coupled to control unit 30, and is used to output rhythm strips and textual information before, during, and after operation.
• conventional defibrillators receive their electric energy from either an AC source (such as a power line) or a battery (e.g., disposable or rechargeable).
• an AC source such as a power line
• a battery e.g., disposable or rechargeable.
• the use of the defibrillator is limited to situations where line power is available and reliable.
• Line power is not available or reliable when, for example, there are blackouts, brown outs, natural disasters, or the like.
• Battery powered defibrillators are mobile but limited in other ways and thus have several disadvantages. For example, after a defibrilU or has been used, or after a set maintenance interval, the battery must either be replaced or recharged by the external battery charger. After numerous recharges by the battery charger, a rechargeable battery should be replaced as its effective charge retention diminishes.
• a battery adds significant size and weight to a battery-open ⁇ ed device's overall configuration.
• batteries have a limited power supply, which requires defibrillator operators to charge and monitor battery energy levels.
• battery charging or battery replacement may not be an option, due to a lack of a power source for recharging, or for a lack of spare batteries.
• the batteries gradually lose their energy supply, or degrade.
• a medical device that receives its energy from a source of mechanical energy would be advantageous in various applications.
• conventional medical devices that are operated by hospital personnel (“in-hospital”) or by trained personnel before the patient can be brought to the hospital, e.g., by paramedics (“pre-hospital”) require a reliable power source. Maintenance errors, or malfunctioning or degraded power sources, may all adversely affect the power source reliability. For pre-hospital and in-hospital uses, errors that occur during monitoring and maintenance of battery charges or line power failures could be eliminated by a medical device having an alternative power source.
• an electrical medical device that operates without batteries or line power is advantageous for an emerging application for certain medical devices (such as defibrillators): "fire extinguisher” medical devices.
• Fire extinguisher defibrillators are located in places (e.g., wherever fire extinguishers are located) where they will be needed to provide easy and reliable operation, even by untrained personnel. Such defibrillators would be better served if there were no batteries to degrade over time or line power to fail. These defibrillators would thus not be affected by the battery or line power problems associated with smoke detectors.
• battery powered medical devices have disadvantages in foreign applications. For example, certain batteries may not be available in certain countries. Also, because of environmental laws, use and disposal of certain batteries is difficult. Further, battery rechargers and line power medical devices must be designed or adapted to use with the foreign power source.
• the cardiac defibrillator includes a device for storing mechamcal energy, a generator, a capacitor, a charging circuit, a patient interface, an input device, and a control unit.
• the generator coupled to the mechanical energy storage device, converts mechamcal energy stored in the mechamcal energy storage device into electrical energy.
• the charging circuit coupled to the generator and the capacitor , transfers the electrical energy to the capacitor, wherein the electrical energy is stored in the capacitor.
• the patient interface coupled to the capacitor and the patient, provides an electrical path for discharging the electrical energy stored in the capacitor into the patient.
• the input device generates a discharge signal.
• the control unit coupled to the capacitor and input device, controls the discharge of the electrical energy into the patient in response to the discharge signal.
• the medical device comprises a device for storing mechanical energy and a generator.
• the generator coupled to the mechamcal energy storage device, converts mechanical energy stored in the mechamcal energy storage device into electrical energy used to power the medical device.
• Another embodiment of the invention relates to a method for powering a medical device by imparting potential mechanical energy into a mechanical energy storage device, converting the potential mechamcal energy of the mechanical storage device into electrical energy with a generator, and powering the medical device using the electrical energy.
• Another embodiment of the invention relates to a medical device including means for storing mechanical energy, means for converting the stored mechamcal energy to electrical energy and control means coupled to the converting means for controlling the medical device.
• FIGURE 1 is a block diagram showing the components of a conventional defibrillator
• FIGURE 2 is a block diagram showing the components of a first exemplary embodiment of a mechanically-powered defibrillator
• FIGURE 3 is a block diagram showing the components of a second exemplary embodiment of a mechanically-powered defibrillator.
• FIGURE 4 is a block diagram showing the components of a third exemplary embodiment of a mechanically-powered defibrillator. DETABLED DESCRIPTION OF PREFERRED EMBODIMENTS
• a medical device powered by electrical energy converted from mechamcal energy could be one of several medical devices, described herein is a cardiac defibrillator. It would be understood that such an alternative power source could be used with other electrical medical devices, such as diagnostic electrocardiogram equipment.
• one embodiment of the invention includes a power supply that converts mechanical energy stored in a structure (such as a coil, spiral, or gas spring), to electrical energy to power the cardiac defibrillator capacitor.
• a structure such as a coil, spiral, or gas spring
• mechamcal energy is released to exert, preferably through a coupled gear mechanism, mechanical energy on a device (such as a dynamo) that converts the mechamcal energy into electrical energy.
• the electrical energy is stored in the defibrillator' s circuitry (such as by charging a capacitor).
• Such a feature eliminates the reliance on line power, or on an external battery charging apparatus or battery maintenance program, and because the defibrillator operator can stress the spring and recharge the capacitor in the field at any time, such a feamre prevents the chance of having a defibrillator incapable of use due to a power line failure, or a weak or dead battery.
• FIGURE 2 shows the general arrangement of a defibrillator 110 including a generator assembly 120, a control unit 130, a charging circuit 140, a capacitor 150, and a patient interface 160.
• Generator assembly 120 includes a mechanical input device 122 (such as a crank), a mechanical energy storage device 124, a coupled mechamsm 126, and a generator 128.
• Mechanical input device 122 is operably coupled to mechanical energy storage device 124, which is coupled to generator 128, preferably through coupled mechanism 126.
• the input of mechanical power into mechanical energy storage device 124 using mechanical input device 122 can take a variety of embodiments.
• a hand operated crank is used to stress a spring. As the spring unwinds, generator 128 is driven to provide a source of electrical energy for the defibrillator.
• a foot actuated device compresses a spring, which subsequently decompresses and drives generator 128.
• a hand pull-cord is used to provide rotational mechamcal energy to generator 128.
• a shaft coupled to generator 128 rotates.
• the hand operated crank is preferred because a hand driven mechamsm tends to be more reliable; that is, with the foot actuated device, the potential exists for damaging the device.
• the hand operated crank preferably includes a retractable crank with a handle (so during transport the handle is substantially flush mounted and is less susceptible to receiving blows).
• Generator 128 is conventional and therefore all possible embodiments are not described in detail.
• a dynamo includes a rotor and a stator.
• the rotor includes one or more magnets
• the stator includes a plurality of coil windings and substantially surrounds the rotor.
• coupled gear mechanism 126 rotates the rotor relative to the stator using power supplied by device 124. As the rotor rotates, the mechamcal energy is converted to electrical energy.
• the generator 128 converts the mechamcal energy into electrical energy.
• Mechanical energy storage device 124, coupled mechanism 126, and generator 128 may be integrated together into a single arrangement, as conventionally known and available in the mechanical/electrical arts.
• the generator assembly 120 includes a dynamo and a spring, wherein the defibrillator operator stresses and releases the spring by compressing it and allowing it to decompress or unwind.
• the decompressing spring actuates a coupled gear mechamsm, which is coupled to the dynamo.
• the dynamo converts the rotation of the coupled gear mechanism to electrical energy.
• the spring may be one of a variety of spring types, including a spiral spring, a coil spring, a gas, or the like.
• a spiral spring dynamo includes a spiral spring coupled to the shaft of a dynamo, a coupled mechamsm connected to the shaft, and the dynamo.
• mechamcal energy is stored in the spiral spring by rotating a shaft (e.g., by a crank, knob, or the like) coupled to the spiral spring.
• a stop pin may be included on the shaft to prevent overrotation of the spiral spring.
• the coupled mechanism is operably engaged.
• the shaft may be coupled directly to the dynamo
• the coupled mechamsm may be comprised of one or more gears for maximum mechamcal advantage and efficiency.
• the dynamo includes a flywheel operably coupled to the coupled drive. Thus, rotation of the flywheel rotates the rotor, thus electric energy is produced.
• a coil spring dynamo the mechamcal energy is stored in a coil spring when the coil spring is stressed (i.e., compressed or stretched) by a button, lever, foot pedal, or the like.
• a coupled gear mechanism rotates the flywheel of the dynamo.
• the coupled gear mechamsm can be actuated by a rack and pinion gear coupled to the coil spring, or the like. As the coil spring returns to a unstressed state, the rack and pinion induces rotation of the coupled gear mechamsm.
• a gas spring dynamo the mechamcal energy is stored is a chamber when a gas (such as air) is compressed by a pump actuator, foot pedal, lever, or the like.
• a gas such as air
• the coupled mechanism is actuated to drive the generator.
• Defibrillator 110 further includes a second capacitor 129.
• the output of generator 128 is also used to charge second capacitor 129, which is used to power control unit 130.
• Control unit 130 is configured to control the operation of defibrillator 110 and provide the defibrillator operator a display (not shown) to view.
• Control unit 130 is electrically coupled to patient interface 160 and capacitor 150. When the defibrillator operator instructs defibrillator 110 to deliver the charge to the patient, control unit 130 signals capacitor 150 to pass the stored charge to the patient through patient interface 160.
• Charging circuit 140 transfers the electrical charge from generator assembly 120 to capacitor 150.
• Capacitor 150 and control unit 130 are electrically coupled to patient interface 160.
• Capacitor 150 holds the charge until control unit 130 instructs the charge be delivered or discharged into a patient through patient interface 160.
• Patient interface 160 usually includes either pads, paddles, or internal spoons that physically contact to the patient. In a medical device other than a defibrillator, the patient interface could be configured to interface or communicate with the patient.
• defibrillator 110 further includes a printer 170 which is electrically coupled to control unit 130 and is used to output a hard copy of rhythm strips and textual information. Such output is then reviewed by the defibrillator c aerator while treating the patient.
• printer 170 which is electrically coupled to control unit 130 and is used to output a hard copy of rhythm strips and textual information. Such output is then reviewed by the defibrillator c aerator while treating the patient.
• Defibrillator 110 further includes an input device 162 which is configured to provide the defibrillator operator with an interface to operate defibrillator 110.
• Innut device 162 is adapted to signal the defibrillator to discharge or to output information to printer 170.
• Input device 162 may be operator acmatable or automatically actuatable. When input device 162 is operator- actuatable, the defibrillator operator physically actuates input device 162. When the defibrillator operator actuates input device 162 and instructs defibrillator 110 to deliver the charge to the patient, control unit 130 signals capacitor 150 to pass the stored charge to the patient through patient interface 160.
• operator- actuatable input device 162 examples include buttons on patient interface 160 (e.g., when paddles or internal spoons are being used), or buttons on control unit 130 (e.g., when pads are being used).
• control unit 130 includes a conventionally known device that triggers the input device if the condition of the patient warrants. Such devices are intended to operate "automatically," i.e., without direct defibrillator operator control. In a medical device other than a defibrillator, the input device could be configured to signal the medical device to perform a function, such as actuate a mechanism, take a measurement, run a diagnostic analysis, interface or communicate with the patient, or the like.
• the defibrillator operator exerts energy on mechamcal energy storage device 124 using input device 122 (e.g., winds a spring to a predetermined point).
• mechamcal energy storage device 124 releases the stored mechamcal energy (e.g., unwinds)
• generator 128 converts the mechamcal energy to electrical energy.
• mechamcal energy After mechamcal energy is applied to mechamcal energy storage device 124, it may be immediately released for use, or it may be stored by mechamcal energy storage device 124 for release at a later time.
• the defibrillator is generally left in an uncharged and unwound stat
• the electrical power of generator 128 is passed to charging circuit 140 which steps up the voltage as necessary to charge capacitor 150 that is used to deliver the charge to the patient.
• FIGURE 3 illustrates the general arrangement of a defibrillator 210, which is partially powered by a battery 180.
• the defibrillator 210 includes a generator assembly 120, a control unit 130, a charging circuit 140, a capacitor 150, a patient interface 160, and a printer
• Defibrillator 210 primarily uses generator assembly 120 to power the operation of the system.
• Generator assembly 120 includes mechanical input device 122, a mechamcal energy storage device 124, coupled mechamsm 126, and a generator 128.
• Mechanical energy storage device 124 is coupled to generator 128 such that when the mechamcal energy in mechamcal energy storage device 124 is released (e.g., when a spring is allowed to decompress or unwind), the mechamcal potential energy is converted by generator 128 into electrical energy.
• Mechamcal energy storage device 124 and generator 128 arrangement is conventionally known and available in the art of mechanical/electrical power conversion.
• the output of generator 128 provides electrical energy to charging circuit 140.
• Charging circuit 140 transfers the electrical charge from generator assembly 120 to capacitor 150.
• Capacitor 150 is electrically coupled to patient interface 160. Capacitor 150 holds the charge until control unit 130 instructs the charge to be delivered or discharged into a patient through patient interface 160.
• Patient interface 160 usually includes either pads or paddles that are physically connected to the patient.
• control unit 130 being powered by generator assembly 120
• control unit 130 is powered by one or more batteries 180.
• battery 180 is a small conventionally available disposable or rechargeable type (e.g., 9-volt or double-A (i.e., AA)). Battery 180 is electrically coupled to low battery indicator 184.
• AA double-A
• Low power indicator 184 is conventionally available and is configured to signal the defibrillator operator that battery 180 has a low charge.
• low power indicator 184 is configured to signal the operator that the stored electrical energy, which had been converted from mechamcal energy, is low.
• Low power indicator 184 signals the operator by a flashing light or a conventional "chirp" circuit to draw attention to the operator that the stored electrical energy is low or that battery 180 needs to be replaced.
• battery 180 is replaced or recharged.
• mechamcal input device is actuated and generator 128 converts the mechamcal energy to electrical energy.
• printer 170 is electrically coupled to control unit 130 and is used to output a hard copy of rhythm strips and textual information.
• FIGURE 4 shows the general arrangement of a defibrillator 310 wherein the defibrillator is partially powered by a solar power-rechargeable battery 186.
• Defibrillator 310 includes a generator assembly 120, a control unit 130, a charging circuit 140, a capacitor 150, a patient interface 160, and a printer 170.
• Control unit 130, charging circuit 140, capacitor 150, and patient interface 160 operate substantially the same as described in FIGURE 2 and so are identified by similar reference numerals.
• Defibrillator 310 primarily uses generator assembly 120 to power the operation of the system and includes mechanical input device 122, a mechamcal energy storage device 124, a coupled mechamsm 126, and a generator 128.
• Mechanical energy storage device 124 is coupled to g-nerator 128 such that when stored mechamcal energy of mechanical energy storage device 124 is released (e.g., a spring is allowed to decompress or unwind), the mechamcal energy is converted by generator 128 into electrical energy.
• the electrical energy is stored in capacitor 150 until it is discharged into the patient through patient interface 160.
• the energy output of generator 128 provides electrical energy to charging circuit 140.
• the charging circuit 140 stores the electrical charge from generator assembly 120 in capacitor 150, which is electrically coupled to patient interface 160. Capacitor 150 holds the charge until control unit 130 instructs patient interface 160 to deliver or discharge into a patient.
• Patient interface 160 usually includes either pads or paddles that are physically connected to the patient.
• control unit 130 is powered by rechargeable battery 186.
• rechargeable battery 186 is embedded in control unit 130. Whether rechargeable battery is embedded or not, rechargeable battery 186 can be recharged by any conventional means. As shown in FIGURE 4, rechargeable battery 186 is charged by solar cell 188 that uses the ambient light as a power source
• printer 170 is configured to output a hard copy of rhythm strips and textual information.
• Printer 170 is electrically coupled to rechargeable battery 186 through control unit 130.
• batteries are the number one source of failure with defibrillators
• using a mechanical-to-electrical energy converting assembly as disclosed herein solves this industry-wide problem.
• batteries used for defibrillators require daily maintenance and testing.
• replacement batteries can be difficult to obtain.
• the disclosed energy converting assembly eliminates the need for replacement of batteries that operate a defibrillator and for external battery chargers.
• in-hospital defibrillators no longer need to be continuously plugged in. Further, the patient receives better care because there is no limit on the number of discharges that can be delivered; that is, the device will not fail due to a weakened or de.d battery.
• Field applications such as military or civilian humanitarian, often take place far from a source of reliable power. Because the battery charging step is eliminated, and AC line power is not needed, the mechanically-powered defibrillator car be deployed anywhere.
• the energy converting defibrillator is important for an emerging defibrillator application.
• so-called "fire extinguisher” defibrillators i.e., small defibrillators that can be deployed anywhere
• a defibrillator that is immediately assessable and requires minimum maintenance in need.
• a dynamo powered defibrillator can sit on the shelf before being used with the potential for battery failure being reduced or eliminated.
• FIG. 1 While the embodiments illustrated in the FIGURES and described above are presently preferred, it should be understood that these embodiments are offered by way of example only. Other embodiments may include, for example, various configurations of mechamcal input devices, mechamcal storage devices, coupled mechanisms (or elimination thereof), generators, spring dynamo assemblies, or defibrillators. Moreover, although a cardiac defibrillator was described by way of an example, it should be understood that an apparatus that converts mechamcal energy to electrical energy could be used in other medical devices that operate on electrical energy. The invention is not limited to a particular embodiment but extends to various modifications, combinations, and permutations that nevertheless fall within the scope and spirit of the appended claims.

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• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Radiology & Medical Imaging (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
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• Heart & Thoracic Surgery (AREA)
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• 1999
  • 1999-10-07 US US09/414,468 patent/US6556867B1/en not_active Expired - Fee Related
• 2000
  • 2000-10-02 DE DE10083519T patent/DE10083519B3/de not_active Expired - Fee Related
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