Patent ID: 7822471
Filing Date: 2010-10-26
Classification: A61B,A61N

Abstract:
1. A method for detecting in an electrocardiogram of a patient artifact signals caused by CPR and patient motion, independently of the patient's electrocardiogram signal, the method comprising: obtaining samples of transthoracic impedance signals of the patient independently of the patient's electrocardiogram signal by acquiring and monitoring and measuring impedance signal data from the patient for a given time period by application to the patient of a constant current input signal to produce an output voltage in proportion to the patient's impedance, and using such samples as an indicator of underlying ECG rhythm classification; simultaneously tracking the patient's electrocardiogram signals and changes in the output voltage proportionate to the transthoracic impedance; sensing the condition of the patient's heart by an ECG sensing current; dividing the transthoracic impedance samples into equal three-second segments of time, each segment of time comprising impedance signal data for the segment of time, and dividing each of the three-second segments into 0.5-second samples of impedence and classifying the impedance signal data in each 0.5-second segment of time as a segment containing non-shockable artifact signals or not containing artifact signals and therefore shockable; and evaluating the three-second segments to detect the presence of CPR and for characteristics indicative of artifact signals caused by CPR and patient motion; whereby to detect the presence of CPR and motion defects in the ECG signal and thereby improve determinations of shockable conditions.