Up to this time, the most exact methods for monitoring of extracellular lung water involve either complex technologies that are not applicable for continuous measurement nor for use on an ICU or in the operative theatre such as Evolution-CT-scan, or invasive procedures such as algorithms based upon data derived from thermo-dilution measurements requiring both central venous and femoral catheters. In clinical practice, there is need for a reliable, easily applicable, noninvasive online monitoring system for extracellular fluid in the lungs.
The goal of the project is the development of such a system based on the measurement of the electrical conductivity of tissue. As the frequency dependence (spectrum) of the conductivity depends characteristically on the hydration, focused conductivity spectroscopy (FCS) is a promising method for the project realization. In contrast to previously developed related methods (electrical impedanc tomography, EIT) FCS aims at the direct reconstruction of a pulmonary edema index (derived from the conductivity) with high specificity in a defined region of interest. Its non-invasiveness and the robust, miniaturizable instrumentation make FCS particularly suitable for on-line monitoring of post-surgical patients.