Patent ID: 7818155
Filing Date: 2010-10-19
Classification: A61B

Abstract:
1. A method of identifying and classifying reflux episodes in a plurality of impedance versus time waveforms obtained simultaneously at a plurality of different locations spaced apart from each other along a length of an esophagus between the pharynx and the stomach along with a pH versus time curve obtained in the esophagus, wherein the impedance versus time waveforms include proximal waveforms from the locations closest to the pharynx, distal waveforms from the locations closest to the stomach, and mid-channel waveforms between the proximal waveforms and the distal waveforms, said method comprising: applying a smoothing algorithm to the impedance versus time waveforms; locating candidate transition points and candidate end points in the smoothed waveforms to indicate candidate reflux episodes; determining whether a pH drop occurs in the pH versus time curve contemporaneous with a candidate transition point to thereby indicate whether the candidate reflux episode associated with such candidate transition point is acidic or non-acidic; determining a gastric contents impedance threshold for acid reflux episodes; determining a gastric contents impedance threshold for non-acid reflux episodes; determining if there is impedance of acid gastric contents associated with the candidate acid reflux episodes by comparing values associated with impedance at the candidate transition points for candidate acid reflux episodes to the gastric contents impedance threshold for acid reflux episodes; determining if there is impedance of non-acid gastric contents associated with the candidate non-acid reflux episodes by comparing values associated with impedance at the candidate transition points for candidate non-acid reflux episodes to the gastric contents impedance threshold for non-acid reflux episodes; for candidate acid reflux episodes wherein there is impedance of acid gastric contents, determining if there is a propagation direction of corresponding candidate transition points in any of the other impedance versus time waveforms starting from a distal waveform; for candidate non-acid reflux episodes wherein there is impedance of non-acid gastric contents, determining if there is a propagation direction of corresponding candidate transition points in any of the other impedance versus time waveforms starting from a distal waveform; classifying candidate acid reflux episodes as actual acid reflux episodes based at least in part on determination that there is impedance of acid gastric contents and on determination that there is propagation direction; and classifying candidate non-acid reflux episodes as actual non-acid reflux episodes based at least in part on determination that there is impedance of non-acid gastric contents and on determination that there is propagation direction.