Impaired Cation Transport May Lead to Bioelectrical Impedance Changes during Hepatic Ischemia

PURPOSE: Ischemia and reperfusion (I/R) injury is a major cause of hepatic failure after liver surgery, but there is no direct method to monitor it in real-time (like an electrocardiogram in heart disease) during surgery. Recently we found the possible role of bioelectrical impedance (BEI) to monitor I/R injury in liver. But the mechanism responsible for ischemia-related BEI changes has not been clearly determined. METHODS: The authors used an LCR meter to quantify BEI changes at 0.12 KHz. Livers were subjected to 70% partial ischemia for 120 minutes, and ATP contents, cation changes in extracellular fluid (ECF; determined using an in vivo intracellular microdialysis technique), hepatocyte sizes, and histological changes were then examined. RESULTS: Liver tissue BEI was found to increase gradually during the first 60 minutes of ischemia and then tended to plateau. During the same period, intracellular ATP contents decreased to below 20% of the baseline level, [Na+] in ECF decreased from 150.4+/-3.8 to 97.8+/-10.6 mmol/L, and [K+] in ECF increased from 7.5+/-0.3 to 34.3+/-5.5 mmol/L during the first 60 minutes of ischemia. Hepatocyte diameter increased by ~20% during the first 60 minutes of ischemia. CONCLUSION: This study suggests that BEI changes during hepatic ischemia are probably caused by sodium and potassium concentration changes in the ECF due to reduced intracellular ATP contents.

Gaining Experience before Establishing a Totally Laparoscopic Left Lateral Sectionectomy as a Standard Procedure

PURPOSE: The aim of this study was to present our experience before establishing laparoscopic left lateral sectionectomy (LLLS) of the liver as a standard procedure, and to show efficacy of a totally LLLS compared to an open left lateral sectionectomy (OLLS). METHODS: We retrospectively analyzed and compared clinical outcomes (operation time, blood loss, hospital stay, complication rate, etc) for 29 patients who underwent LLLS and 27 patients who underwent OLLS between January, 2002 and December, 2009. To see the learning curve for LLLS, we arbitrarily divided the LLLSs we did into an early group (ELLLS) and a late group (LLLLS) based on when they were operated on relative to case number 14. RESULTS: Mean operative times for the ELLLS, LLLLS and OLLS groups were 269.7+/-102.6, 210.0+/-47.9 and 289.1+/-72.8 minutes, respectively. Mean operative time was significantly shorter (p<0.05) in the LLLLS than the OLLS group. Mean intra-operative blood loss was also less in the LLLLS group than the OLLS group (80.00+/-224.2 ml vs. 195.15+/-405.4 ml). Post-operative hospital stay was shorter in the LLLLS group than the OLLS group (9.9+/-4.0 versus 16.9+/-9.1, p=0.071). CONCLUSION: The totally LLLS is a safe, feasible treatment option that can be a standard procedure with better outcomes in selected patients after an initial learning curve.

Bioelectrical Impedance May Predict Cell Viability During Ischemia and Reperfusion in Rat Liver

Ischemia and reperfusion (I/R) injury is a major cause of hepatic failure after liver surgery, but no method could monitor or predict it real-time during surgery. We measured bioelectrical impedance (BEI) and cell viability to assess the usefulness of BEI during I/R in rat liver. A 70% partial liver ischemia model was used. BEI was measured at various frequencies. Adenosine triphosphate (ATP) content, and palmitic acid oxidation rate were measured, and histological changes were observed in order to quantify liver cell viability. BEI changed significantly during ischemia at low frequency. In the ischemia group, BEI increased gradually during 60 min of ischemia and had a tendency to plateau thereafter. The ATP content decreased below 20% of the baseline level. In the I/R group, BEI recovered to near baseline level. After 24 hr of reperfusion, the ATP contents decreased to below 50% in 30, 60 and 120 min of ischemia and the palmitic acid metabolic rates decreased to 91%, 78%, and 74%, respectively, compared with normal liver. BEI may be a good tool for monitoring I/R during liver surgery. The liver is relatively tolerant to ischemia, however after reperfusion, liver cells may be damaged depending upon the duration of ischemia.