Bioimpedance analysis of the spleen after experimental extended liver resection

Abstract

Background. Post-resection liver failure is considered the most serious complication of extended liver resections. One of possible directions in the search for diagnostic and prognostic criteria of liver failure severity is studying the effect of extended liver resection on morphology and function of the spleen. Aim. To evaluate parameters of full electrical resistance of the spleen following extended liver resection. Materials and methods. The study was performed on 20 Wistar rats weighing 180–230 g. Extended liver resection was modeled by removing 70% of the organ. Prior to the surgery, immediately after the surgery, and on postoperative days 3 and 14, invasive bioimpedancemetry of the liver and spleen was performed. Results. Following extended liver resection, biophysical parameters of the liver and spleen parenchyma were characterized by a significant decrease in the impedance at a frequency of 2 kHz compared to normal background values obtained immediately after the removal of a part of the liver. On the 3^rd day after surgery, the liver parenchyma impedance at a measurement frequency of 2 kHz reached a maximum for the entire observation period while the spleen parenchyma impedance did not increase compared to the respective values before extensive liver resection. On the 14^th day of follow-up, the liver parenchyma impedance was significantly decreased compared to the values obtained on the 3^rd day and corresponded to the preoperative values. The spleen impedance was significantly lower than the preoperative values. Histological study performed on the 14^th postoperative day showed signs of depletion of the red and white pulp. Conclusions. The decrease in the spleen impedance observed immediately after extended liver resection was associated with intensified parenchymal blood flow. The decrease in the spleen impedance observed on the 14th day was associated with depletion of the red and white pulp as shown by histological examination.