The EIS provides an electrical signal corresponding to the status of a patient's physiological parameters: Na+/K+ATPase pump activity, tissue pCO2, sympathetic system activity and microcirculation blood flow.
EIS System Device Background A DC current, very low frequency (1 Hz) current and low frequency (from 700 Hz to 1 KHz) current are applied between six tactile electrodes placed symmetrically on the forehead, hands, and feet of the subject. Each electrode is alternatively cathode and anode (bipolar mode from anode to cathode), which permits the records of 22 segments (2816 pulses in 2 minutes) from the human body in multi frequencies. The measured resistance's (Ohm law) are transmitted with a numeric scale for each segment to an informative program. The resistances are converting to conductivities (C = 1/R), incorporated in a graph. The graph of the conductivities of the 22 segments is called an Electro Scan Gram (E.S.G) for each frequency
The EIS system device developers claim this to be a true medical device. They also claim the EIS System device provides traditional medical interstitial fluid physiological values.
Technologies: The used technologies are the Bio Impedance technologies in bipolar mode, Signal Processing analysis and Modeling process.
1. Bio Impedance Technologies The Electrode Polarization Impedance (EPI), The electrical Bio Impedance Analysis (BIA), Bio Impedance Plethysmography (BIP) The Galvanic Skin Responses (GSR) The EPI (1Hz) is used for in vivo estimation of Na+/K+APTase pump activity. The BIA (700 Hz) is used for in vivo estimation of tissue pCo2 The BIP (1 KHz) is used for in vivo estimation of the microcirculation Blood flow. The GSR (DC) is used for the stress evaluation and provides estimation of the sympathetic system activity and emotional arousal.
2. EIS system Signal Processing Analysis:
Steps of the EIS Signal Processing Analysis: Step 1: The Standard Deviation of the conductivities (SDC) provides the estimation of the Na+/K+ATPase pump activity
Step 2: Each 22 measured segments signal is analyzing: The stability of each segment signal (32 pulses) analysis provides the estimation of the tissue pCO2.
Step 3: The Spectrum analysis and the Application of the Discrete Fast Fourier Transform to the entire records (2816 pulses) provide a frequencies graphic where:
HF corresponding to the estimation of the sympathetic system
HF/VLF corresponding to the estimation of the Oxygen uptake/Oxygen available ratio
HF/LF corresponding to the microcirculation blood flow.
3. Modeling Technology Treatment plans made by doctors rely on predictions based on statistical averages. The physiology of the human body is complex and individual, but advanced computational methods enable the modeling of the body. Designing a reliable model requires accurate information about the functioning and anatomy of the body and about the properties of tissues. Advances in computing power enable utilization of quite complex models in the daily work of doctors.
As the possibilities of treating diseases improve, it is important to choose the right treatment for each individual patient. Today, a doctor may be able to use a virtual model to test how the planned treatment would affect a patient, and can choose the best treatment method in each individual’s case.
EIS Modeling Process The EIS modeling process is related with the Analysis of the ESG graph in domain analysis with the following steps:
Scale conversion: EIS conversion from the scale 0-100 to -100/+100
The modeling of the EIS system is made according to a color code from blue to red related to the conductivity (from 0 to 110 10-6 S.m-1) of the zone.