Dielectric Properties for Instantaneous Evaluation of Ischemic Injury of the Liver in the Rats in Normothermia

Hideo Itoh, Hajime Hirose, Eisaku Sasaki, Makoto Ishikawa, Yoshifumi Katagiri, Hirokazu Matsutomo, Masatoshi Hayashi, Shoushi Senga, Masatomo Hayashi and Atsuyoshi Onitsuka

First Department of Surgery, Gifu University School of Medicine

The purpose of this study was to evaluate ischemic injury of the liver by Pringle method during hepatectomy. Electrical impedance was used for instantaneous evaluation of the normothermic ischemic injury of the liver in Wistar rats, which had received a portal bypass by the subcutaneously transposed spleen. Four ischemic groups (15, 30, 60, and 120 minutes) were studied and then received a reperfusion. Conductance was measured with an LCR meter and then resistivity was calculated. Bile flow during experiments was measured. The preischemic value of ρ at 1kHz was 1,038±98 (mean±SD) ohm·cm. In the early phase of ischemia ρ increased and reached a peak (ρm). After the peak, ρ decreased to the point of reperfusion (ρr). The time from initiation of the ischemia to &rhom was 35±5.9 minutes. Adenosine triphosphate (ATP) in the liver was measured by high performance liquid chromatography. The ATP level in the liver decreased with ischemic time, 40.5±2.9% at 20 minutes and 36±5.6% at the time of ρm. Microscopically, the ischemic damage of the liver was little up to 30 minutes and severe at 60 minutes of ischemia. Recovery of the bile flow one hour after reperfusion in each group was 98.2±6.2, 90.6±0.5, 23.9±15.6, and 6.96±4.2%.ρ has significant inverse correlations with ATP in the early ischemic period to ρm and then a ρr/ρm has positive correlation with recovery of the bile flow one hour after reperfusion. These results suggests that electrical impedance is one of the indices for viability of ischemic injury of the liver in rats.

Key words
liver, viability, electrical impedance, normothermic ischemia, bile flow

Reprint requests
Hideo Itoh First Department of Surgery. Gifu Univ. School of Medicine 40, Tsukasa-machi, Gifu 500-8705 Japan

Accepted
June 22, 1999

To read the PDF file you will need Abobe Reader installed on your computer.