Abstract: In an automatic external defibrillator (AED) having a ventricular fibrillation detector, the ventricular fibrillation detector may generally be defined as a filter containing both an adaptive non-linear section and a linear section. The non-linear section is preferably a complex-domain neural network that can be trained to differentiate between various rhythm patterns and produce linear data for input to the linear section. The linear section is preferably an ongoing, continuous operation based on a sliding window of a predetermined time period, e.g., a tapped time-delay filter. In combination the non-linear section and linear section of the filter operate to detect and extract artifacts from a patient's ECG signal in a substantially accurate fashion so that the determination to deliver a defibrillation pulse may be accurately made.

Abstract: A method for determining an optimal transchest external defibrillation waveform which, when applied through a plurality of electrodes positioned on a patient's torso will produce a desired response in the patient's cardiac cell membranes. The method includes the steps of providing a quantitative model of a defibrillator circuit for producing external defibrillation waveforms, the quantitative model of a patient includes a chest component, a heart component, a cell membrane component and a quantitative description of the desired cardiac membrane response function. Finally, a quantitative description of a transchest external defibrillation waveform that will produce the desired cardiac membrane response function is computed. The computation is made as a function of the desired cardiac membrane response function, the patient model and the defibrillator circuit model.

Abstract: The present invention discloses a method and device in which an external defibrillator is integrated with an algorithm implemented in a programmable microprocessor which controls and manages the formation of defibrillation waveforms. The waveforms are dynamically adjusted and created to be consistent with a myocardial cell response waveform. Dynamic tilt calculations based on time slices and corresponding fit functions based on best-fit models are used to generate the waveforms. The waveforms include a first and a second phase and are formed with minimal delay therebetween.

Abstract: An energy delivery system for use with an automatic external defibrillator (AED), the AED having a case containing a plurality of AED components, a battery electrically coupled to a control system, the control system communicatively coupled to a charge system, the charge system for generating a stored quantity of energy responsive to a communication from the control system, the control system selectively commanding a discharge of the stored energy to an electrical connector, the energy delivery system includes three electrodes, each electrode for making electrical contact with a skin surface of a patient, each electrode being in electrical contact with the electrical connector for communicating the stored energy to the patient.

Abstract: A force sensor, for use in combination with an automated electronic defibrillator (AED), includes a first conductive layer. A second conductive layer is spaced apart from the first conductive layer such that no electrical communication occurs between the first and second conductive layers. An electrical communication device is provided for establishing electrical communication between the first and second conductive layers responsive to the application of a force to said electrical communication means.

Abstract: Defibrillator electrodes having an identification element and a circuit which indicates to an AED the weight range of the patient being rescued. When the AED detects the presence of pediatric electrodes, it may select a different set of voice prompts that are specifically suited to a pediatric patient and/or it may select a pediatric dosage of electricity for the therapeutic shock.

Abstract: A method and apparatus for pretreating a patient prior to a therapeutic painful stimulus, comprising the application of pain inhibiting stimuli to a patient prior to an application of the therapeutic painful stimulus. Applying pain inhibiting stimuli comprises the steps of sensing a need for the therapeutic painful stimulus, preparing to deliver the pain inhibiting stimuli to the patient prior to applying the therapeutic painful stimulus, and delivering the pain inhibiting stimuli to the patient prior to applying the therapeutic painful stimulus. The method and apparatus are embodied in modem, fully automatic, fully implantable, single or dual chamber atrial or ventricular cardioverter-defibrillators. The pain inhibiting prepulse method is intended primarily for use in conscious patients but may also be used in sleeping patients.

Abstract: The present invention is an external defibrillator which controls and manages the formation of defibrillation waveforms. The waveforms are dynamically adjusted and created to be consistent with a myocardial cell response waveform. Dynamic tilt calculations based on time slices and corresponding functions based on best-fit models are used to generate the waveforms. The waveforms are dynamically adjusted to compensate for changes in resistance due to changes in the voltage during delivery of the waveform. The waveforms include a first and a second phase and are formed with minimal delay therebetween.

Abstract: An apparatus for generating a waveform for use in externally defibrillating the heart of a patient includes a plurality of capacitors chargeable to respective charge potentials. A control apparatus is operatively coupled with the capacitors to sequentially interconnect the capacitors in a circuit with one another to generate the waveform. Structure including e.g. electrodes is operatively coupled with the capacitors and the control apparatus to apply the waveform to the chest of the patient. The waveform preferably includes an emulated first-phase substantially sinusoidally shaped pulse component having a first polarity. According to biphasic embodiments, the waveform also includes an emulated second-phase substantially sinusoidally shaped pulse component having a second polarity. The control apparatus preferably is constructed to truncate the emulated first-phase pulse component at a predetermined time, preferably based on a design rule used to calculate pulse duration.

Abstract: A method for determining an optimal transchest external defibrillation waveform which, when applied through a plurality of electrodes positioned on a patient's torso will produce a desired response in the patient's cardiac cell membranes. The method includes the steps of providing a quantitative model of a defibrillator circuit for producing external defibrillation waveforms, the quantitative model of a patient includes a chest component, a heart component, a cell membrane component and a quantitative description of the desired cardiac membrane response function. Finally, a quantitative description of a transchest external defibrillation waveform that will produce the desired cardiac membrane response function is computed. The computation is made as a function of the desired cardiac membrane response function, the patient model and the defibrillator circuit model.

Abstract: A method of generating and applying a defibrillation shock of the present invention includes first applying a defibrillation shock pulse to a patient with an initial predetermined amount of energy not based on a patient-dependent electrical parameter, and while monitoring a patient-dependent electrical parameter. Next, patient transthoracic impedance is determined based on the patient-dependent electrical parameter. Finally, a subsequent predetermined amount of energy is applied to the patient based on the patient transthoracic impedance calculated above and while monitoring the patient-dependent electrical parameter. Subsequent defibrillation shock pulses are applied using a patient impedance based on the patient-dependent electrical parameter observed during the most recent defibrillation shock. In this manner, an optimal combination of charged voltage and the maximum allowed current (under the AAMI defibrillation waveform standard) is applied for a patient's given transthoracic impedance.

Abstract: A method and apparatus for generating biphasic waveforms uses an implantable cardioverter defibrillator (ICD) system having a phase transition enhancing capacitor system in addition to the capacitor system(s) which deliver the first and second phase of the biphasic countershock. Preferably, the ICD system has at least three capacitor systems and a capacitor switching network. The three capacitor systems include two primary capacitor systems and a third high voltage phase transition enhancing capacitor system having a time constant shorter than the time constant of the two primary capacitor systems. A first phase of the biphasic waveform preferably is produced by configuring the two primary capacitor systems to selectively discharge first in a parallel combination, and then in a series combination. The second phase of the biphasic waveform preferably is produced by reconfiguring the two primary capacitor systems to discharge in a parallel combination with reversed polarity.

Abstract: An apparatus for generating a waveform for use in externally defibrillating the heart of a patient includes a plurality of capacitors chargeable to respective charge potentials. A control apparatus is operatively coupled with the capacitors to sequentially interconnect the capacitors in a circuit with one another to generate the waveform. Structure including e.g. electrodes is operatively coupled with the capacitors and the control apparatus to apply the waveform to the chest of the patient. The waveform preferably includes an emulated first-phase substantially sinusoidally shaped pulse component having a first polarity. According to biphasic embodiments, the waveform also includes an emulated second-phase substantially sinusoidally shaped pulse component having a second polarity. The control apparatus preferably is constructed to truncate the emulated first-phase pulse component at a predetermined time, preferably based on a design rule used to calculate pulse duration.

Abstract: A method and apparatus for delivering a stepped truncated damped sinusoidal external defibrillation waveform which, when applied through a plurality of electrodes positioned on a patient's torso will produce a desired response in the patient's cardiac cell membranes is provided. Further, the method and apparatus sufficiently approximates a constant current defibrillation shock pulse. The method includes the steps monitoring a patient-dependent electrical parameter and determining a duration based on the parameter determined. First and second charge storage components are then charged. A first truncating switch is then closed to discharge the first charge storage component. After a predetermined delay, a second truncating switch is closed to discharge the second charge storage component. Then, after the duration period that was calculated has expired the switches are opened to truncate the waveform.

Abstract: A method and apparatus for delivering a truncated damped sinusoidal external defibrillation waveform which, when applied through a plurality of electrodes positioned on a patient's torso will produce a desired response in the patient's cardiac cell membranes is provided. The external defibrillator is utilized for applying a damped sinusoidal waveform having a first waveform phase and a second waveform phase to a pair of electrodes. The external defibrillator has a first capacitive component, a first inductive component, a first truncating switch, and waveform control circuitry. The waveform control circuitry of the defibrillator controls the first and second truncating switches such that the duration of the second phase waveform delivered by the second charge storage component is greater than the duration of the first phase waveform delivered by the first charge storage component.

Abstract: A method and apparatus for delivering a truncated damped sinusoidal external defibrillation waveform which, when applied through a plurality of electrodes positioned on a patient's torso will produce a desired response in the patient's cardiac cell membranes is provided. The method includes the steps monitoring a patient-dependent electrical parameter and determining a duration based on the parameter determined. A first set of charge storage capacitors is then charged. A first truncating switch is then closed to discharge the first set of capacitors. Then, after the duration period that was calculated has expired the switch is opened to truncate the waveform. The computation of discharge duration is made as a function of the desired cardiac membrane response function, a patient model and a defibrillator circuit model.

Abstract: A method for determining an optimal transchest external defibrillation waveform which, when applied through a plurality of electrodes positioned on a patient's torso will produce a desired response in the patient's cardiac cell membranes. The method includes the steps of providing a quantitative model of a defibrillator circuit for producing external defibrillation waveforms, the quantitative model of a patient includes a chest component, a heart component, a cell membrane component and a quantitative description of the desired cardiac membrane response function. Finally, a quantitative description of a transchest external defibrillation waveform that will produce the desired cardiac membrane response function is computed. The computation is made as a function of the desired cardiac membrane response function, the patient model and the defibrillator circuit model.

Abstract: Apparatus and method for selecting from a pair of capacitor banks for delivery of positive and negative polarity portions of a biphasic defibrillator pulse with a selector switch circuit for each capacitor bank, the circuit including a solid state phase selector switch preferably made up of a series connected plurality of IGBT's and each phase selector switch having a phase selector driver and select phase control for turning the phase selector switch ON and OFF when desired to start and truncate selected portions of the biphasic defibrillation pulse.

Abstract: Apparatus and method for parallel charging of mixed capacitors, including a source for generating a train of high frequency pulses coupled through a pulse transformer, a high speed diode connected to the pulse transformer, a filter capacitor connected to the high speed diode and acting as a low-pass filter for the train of pulses, and a plurality of solid state switches for selectively coupling and decoupling the voltage across the filter capacitor to one of a plurality of capacitor banks which make up the biphasic high voltage defibrillation pulse supply.

Abstract: A well logging instrument string including a first section adapted to be operated substantially in contact with a wall of a wellbore, a coupling connected at one end to one end of the first section. The coupling includes first and second flexible joints for enabling relative angular deflection between the first section and a second section. The coupling includes a biasing mechanism for urging at least one of either the first or the second flexible joints, or both, to assume their positions of maximum angular deflection. The instrument string includes a second section connected to the other end of the coupling. The second section is adapted to be operated spaced apart from the wellbore wall.