Hewlett-packard Corporation

Judith Cyrus

Daniel J Powers

J Daren Bledsoe

Steve Kootstra

Ben Flugstad

David C Shultheis

Art Burkhalter

Dan Jordan

A defibfillator has a self healing storage capacitor connected in parallel with a safety resistor, and a microcontroller. Upon receipt of a calibration request, the microcontroller charges the capacitor to a charging voltage greater than a starting voltage, then discharges the capacitor through the safety resistor. As the capacitor is discharging, the microcontroller continuously measures the voltage across the capacitor. When the microcontroller detects that the voltage across the capacitor is less than or equal to a starting voltage, a timer in the microcontroller is started. When the microcontroller detects that the voltage across the capacitor is less than or equal to an ending voltage, the timer in the microcontroller is stopped. The microcontroller then determines an elapsed time between the time the timer was started and stopped. The microcontroller then calculates a capacitance value of the capacitor based on the starting voltage, the ending voltage, and the elapsed time. This capacitance value is stored in memory, and used to calibrate the energy output of the defibrillator by assuring that the self healing storage capacitor has been charged to a voltage level sufficient to deliver the desired amount of energy to a patient.

Method and apparatus for calibrating the energy output of a defibrillator

A defibrillator/monitor architecture is disclosed with a defibrillator-only mode of operation to provide for shocking a patient notwithstanding failure of the monitor subsystem. The defibrillator/monitor subsystem is partitioned into a defibrillator subsystem and a monitor subsystem. The defibrillator subsystem includes the patient charging circuits and other components necessary to carry out basic defibrillation. The monitor subsystem includes an ECG front-end, CRT display, data recorder and other features. In normal operation, the defibrillator subsystem relies on periodic ECG data ready interrupts from the monitor subsystem for system timing. In the event that the ECG interrupts do not arrive within a predetermined time limit, the monitor subsystem is presumed dead and the defibrillator subsystem switches to defibrillator-only mode of operation, in which system timing is provided by a local standby timer.

Integrated defibrillator/monitor architecture with defibrillator-only

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Newberg, OR, United States of America

Judith Cyrus