Purpose of the study: to reveal how the transfusion and the refraining from it affects the neuro-vascular unit in the congenital heart defects correction with cardiopulmonary bypass. Materials and methods: in vitro research, we formed a model of a neurovascular unit, which contains neu-rons, astrocytes and endothelial cells. This cellular model was cultivated in hypoxia conditions with the oxygen saturation levels of 1, 2, 3, 4%. In addition, this unit was cultivated with the pa-tient's serum adding in two different groups - with minimal and maximal levels of system in-flammatory response that we estimated by IL-6 level. Results: We found that during incubation in hypoxic conditions, the level of transendothelial resistance changed in groups with oxygen levels of 1% and 2% only after 4 hours. When we cultivated neurovascular unit cells with patients' sera, we found a minimal level of transendothelial resistance at 4 hours that increased after 24 hours. Permeability analysis showed that its level significantly decreased in the 1% and 2% oxygen group at 60- and 90-minutes relative to the control group. Conclusion: the system inflammatory response has more expressed but less long effect on the neurovascular unit model than hypoxia.