SYSTEMS AND METHOD FOR CHARACTERISTIC PARAMETER ESTIMATION OF GASTRIC IMPEDANCE SPECTRA IN HUMANS

摘要

Impedance spectroscopy has been proposed as a method of monitoring mucosal injury due to hypoperfusion and ischemia In the critically ill The invention Includes an algorithm developed to calculate the characteristic electrical values best describing human gastnc impedance measurements A database of gastnc spectra was obtained from healthy volunteers, cardiovascular surgery and critically ill patients The gastnc spectrum forms two semi circles in the complex domain, divided into low frequency (F 10kHz) and high frequency (F 1OkHz) A fitting algoπthm was developed based on the Cole model, and central characteπstic parameters were calculated The parameters were validated using the normalized mean squared error and 0 7 % of the spectra were discarded From the expeπmental data obtained in humans, the greatest changes observed as the gastnc mucosa becomes ischemic occur at low frequencies, which are specific and sensitive to tissue damage, and vary with the degree of hypoperfusion