Tissue ischemia detection using impedance spectroscopy

The objective of the authors´ research is to develop an innovative technique for monitoring and measurement of tissue perfusion/ischemia levels. Assessment of tissue perfusion/ischemia is of critical importance in plastic and reconstructive surgery, for postoperative monitoring of transplanted muscle flaps. In order to design an instrument that would approximate as closely as possible the requirements of the “ideal” perfusion/ischemia monitor, the authors initiated research to investigate the correlation between tissue impedance measurements at various frequencies, and the tissue pH, a proven indicator of perfusion/ischemia level of the tissue. The authors´ preliminary experiments were performed in vivo on rabbit anterior tibialis muscle with an impedance spectroscopic system that measures the real component of tissue impedance at seven frequencies in the range of 1 kHz to 100 kHz. The obtained results indicate that there is a strong correlation between the tissue resistivities measured, and the independent indicator of tissue ischemia