Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical therapeutic systems
Reexamination Certificate
1999-11-10
2001-06-26
Schaetzle, Kennedy (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical therapeutic systems
Reexamination Certificate
active
06253105
ABSTRACT:
TECHNICAL FIELD
This invention relates to a method and apparatus for delivering electrical energy produced by a defibrillator to a patient experiencing ventricular fibrillation (“VF”). This invention provides a way to use switching devices, with a voltage rating lower than the overall voltage used by the system, to control the voltage delivery and facilitate voltage sharing. This invention may be used with either implantable or external defibrillators.
BACKGROUND OF THE INVENTION
Each day thousands of Americans are victims of cardiac emergencies. Cardiac emergencies typically strike without warning, oftentimes striking people with no history of heart disease. The most common cardiac emergency is sudden cardiac arrest (“SCA”). It is estimated that more than 1000 people per day are victims of SCA in the United States alone.
SCA occurs when the heart stops pumping blood. Usually SCA is due to abnormal electrical activity in the heart, resulting in an abnormal rhythm (arrhythmia). One such abnormal rhythm, VF, is caused by abnormal and very fast electrical activity in the heart. During VF the heart cannot pump blood effectively. Because blood may no longer be pumping effectively during VF, the chances of surviving decrease with time after the onset of the emergency. Brain damage can occur after the brain is deprived of oxygen for four to six minutes.
VF may be treated by applying an electric shock to the patient's heart through the use of a defibrillator. The shock clears the heart of the abnormal electrical activity (in a process called “defibrillation”) by depolarizing a critical mass of myocardial cells to allow spontaneous organized myocardial depolarization to resume.
External defibrillators send electrical pulses to the patient's heart through electrodes applied to the patient's torso. External defibrillators are typically located and used in hospital emergency rooms, operating rooms, and emergency medical vehicles. Of the wide variety of external defibrillators currently available, automatic and semi-automatic external defibrillators (AEDs) are becoming increasingly popular because they can be used by relatively inexperienced personnel. Such defibrillators can also be especially lightweight, compact, and portable. One drawback to current defibrillator designs is the limited availability of high-voltage semiconductors to control voltage delivery. Although SCRs can tolerate a wide range of voltages, they do not turn of readily, which is a desirable feature when delivering a defibrillation energy pulse.
What is needed, therefore, is a defibrillator which can use a collection of widely available switching devices, which have a higher on/off responsiveness, to deliver a high voltage pulse, wherein the switching devices have a voltage rating lower than the overall voltage delivered by the system.
SUMMARY OF THE INVENTION
An electrical energy delivery circuit is provided for defibrillating a patient experiencing VF. The delivery circuit includes a storage circuit for storing electrical energy and having first and second terminals. A steering circuit is coupled with the first terminal of the storage circuit. The steering circuit is for coupling with the patient to transfer the electrical energy stored in the storage circuit to the patient. The storage circuit is comprised of a plurality of series capacitors which are controlled by a series of lower voltage switching devices connected in parallel to the capacitors. The lower voltage switching devices are, for example, IGBTs. By providing lower voltage switching devices, a number of advantages are achieved over conventional defibrillator circuit designs.
REFERENCES:
patent: 4504773 (1985-03-01), Suzuki et al.
patent: 4637397 (1987-01-01), Jones et al.
patent: 4745923 (1988-05-01), Winstrom
patent: 4998531 (1991-03-01), Bocchi et al.
patent: 5078134 (1992-01-01), Heilman et al.
patent: 5111816 (1992-05-01), Pless et al.
patent: 5249573 (1993-10-01), Fincke et al.
patent: 5472454 (1995-12-01), Ozawa
patent: 6041254 (2000-03-01), Sullivan et al.
patent: WO/93/16759 (1993-09-01), None
patent: WO/94/22530 (1994-10-01), None
Agilent Technologie,s Inc.
Schaetzle Kennedy
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