Assessment of the liver microcirculation by laserdoppler flowmetry after extended liver resection in the experiment

Purpose. To assess microcirculation and mechanisms of its regulation in the liver after its extended resection.

Materials and methods. 10 Wistar rats of both sexes weighing 180–270 g which had median laparotomy under general anesthesia were taken in the trial. Microcirculation in the liver of rats was assessed with LAKK-02 Laser-Doppler flowmeter (Russia). A light guide for determining microcirculation was placed on the visceral surface of the right liver lobe; parameters of Laser-Doppler flowmetry (LDF-gram) were registered for 7 min. Then, ligatures were sequentially applied to the left lateral and median lobes of the liver followed by their cutting off; then, about 70 % of the organ were removed. After removal of both liver lobes, LDF-gram was recorded again for 7 minutes with a sensor placed on the visceral surface of the right liver lobe. Basic microcirculation parameters were registered before and after extended liver resection.

Results. After the extended liver resection, average arithmetic parameters of microcirculation in the liver parenchyma decreased by 11.71 % (p < 0.05), which indicates the decrease in the microvasculature perfusion. At the same time, indicators of standard deviation of the microcirculation index and the coefficient of variation did not change statistically significantly. The median maximum amplitude of neurogenic oscillations after the resection increased by 2.3 points (p < 0.05). The amplitude of myogenic oscillations also increased after resection (p < 0.05); however, the degree of increase was less than that of the neurogenic rhythms. It was found that in 70 % of animals the maximum amplitude of endothelial oscillations increased in the liver microcirculation after the extended resection; however, in general, differences between the average endothelial oscillations before and after the resection were not statistically significant.

Conclusion. In the experimental liver resection, the most informative and reliable LDF criteria on ischemia development in the liver stump were average arithmetic microcirculation indices as well as the amplitude of neurogenic and myogenic oscillations. The authors emphasize that the degree of changes in these indices may be a sign of ischemia severity in the liver stump after its resection and may have a prognostic value, although the results obtained require further research.

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