MONITORING OF DAMAGE TO SKELETAL-MUSCLE TISSUES CAUSED BY ISCHEMIA

In medicine, for example during a transplantation, there is a great in terest in noninvasive working methods for measuring organ states under the influence of ischemia. Electrical impedance spectroscopy measurem ents in the frequency range of 100 Hz to 10 MHz were performed on isch emic skeletal muscle tissues of rabbits at 5 degrees C. The measured a lterations of the electrical properties of the ischemic skeletal muscl es were explained with the help of a suitably extended model. Besides the known effects of edema and changes in conductivity of the intra- a nd extracellular medium for ischemic organs in general, the model for skeletal muscle has to be extended by the consideration of the membran e resistance. Between 300-850 min the real part of the macroscopical e lectrical impedance of skeletal muscle decreases during ischemia at fr equencies below 1 kHz. This effect is explained by the model as a resu lt of the reduction of the membrane resistance caused by the opening o f membrane channels. If further investigations would show a correlatio n between the transition from reversible to irreversible damage on the one hand, and the opening of membrane channels caused by ischemia on the other hand, then electrical impedance spectroscopy would be a noni nvasive, easily applicable method to measure the skeletal muscle state during ischemia. (C) 1998 Elsevier Science S.A. All rights reserved.