Aim: to compare the effects of restrictive versus liberal fluid therapy on the duration of mechanical ventilation (MV), total intensive care unit (ICU) stay, and the need for inotropic and vasopressor support during the post-perfusion period and the first 24 hours after surgery in young children undergoing surgical correction of congenital heart defects (CHD).

Materials and Methods. A prospective, randomized, single-center study included pediatric patients (toddlers) with CHD who were assigned to one of two groups. Group 1 received fluid therapy according to a restrictive protocol (RP group, N=65) at 8 mL/kg/h, while group 2 received therapy according to a liberal protocol (LP group, N=67) at 16 mL/kg/h. The study evaluated the dynamics of metabolic disturbances, duration of ventilatory support, postoperative weight gain, and total ICU stay.

Results. Mechanical ventilation time and total ICU stay were longer in the RP group compared to the LP group: 14±5 hours vs. 10±3 hours (P=0.035) and 27±4 hours vs. 23±2 hours (P=0.036), respectively. Mean postoperative weight gain in the LP group was 2.00% vs 0.32% in the RP group (P=0.001). No clinically significant metabolic or electrolyte disturbances were observed in either group, except for elevated K ion levels in the LP group.

Conclusion. These findings contradict previously reported data in adult population with CHD. In toddlers, a liberal approach to fluid therapy resulted in shorter duration of ventilation and ICU stay compared to a restrictive approach. Toddlers are more sensitive to fluid volume and their preload requirements are higher than those of adults.

The aim of the study was to evaluate the relationship between skin microcirculatory parameters and central and cerebral hemodynamic parameters during progressive blood loss.

Materials and Methods. A randomized, prospective, controlled in vivo experimental study was performed using male Wistar rats (250–350 g, N=23) divided into two groups: «hemorrhagic shock» (HS, N=13), with blood loss of 15% and subsequently 35% of estimated circulating blood volume (CBV), and «sham-operated» controls (SO, N=10). After combined anesthesia, femoral artery catheterization, and craniotomy, the following were measured at baseline (stage 1): mean arterial pressure (MAP), cortical cerebral perfusion (LSCI_brain), and skin perfusion in the hindlimb (LSCI_skin) using laser speckle contrast imaging (LSCI). These measurements were repeated after 15% CBV loss (stage 2) and 35% CBV loss (stage 3). Cerebral (CVC_brain=LSCI_brain/MAP) and cutaneous (CVC_skin=LSCI_skin/MAP) vascular conductance indices were calculated. At stage 3, parameters of post-occlusive reactive hyperemia (PORH) in hindlimb skin were additionally assessed. Statistical analysis was performed using STATISTICA 13.0 with non-parametric methods. Spearman's correlation coefficient (R) was used to assess associations between circulatory parameters.

Results. A 15% CBV loss led to a 26% reduction in LSCI_skin (P=0.003 vs SO), with no significant change in LSCI_brain. With further blood loss and a 43% reduction in LSCI_skin (P<0.001 vs SO), LSCIbrain decreased by 14% (P0.001 vs SO). These changes were accompanied by a sustained increase in CVC_brain (P0.001 vs SO at stage 3), while CVC_skin remained unchanged throughout the experiment. In the HS group, blood loss led to a significant decrease in PORH amplitude (P=0.003 vs SO), while microvascular flow reserve increased (P=0.036 vs SO). Before blood loss, moderate positive correlations were found between LSCI_skin, CVC_skin, and CVC_brain. In HS, LSCI_brain correlated with the degree of LSCI_skin reduction (R=0.57, P=0.041), and skin microvascular flow reserve showed a strong positive correlation with arterial blood pH and base excess (BE) (R=0.84, P=0.001). The correlation between LSCI_skin and MAP shifted from a moderate negative correlation at stage 1 to a strong positive correlation at stage 3.

Conclusion. Skin microcirculation parameters (LSCI_skin, CVC_skin, and PORH), as assessed by laser speckle contrast imaging, are promising diagnostic markers of central and cerebral hemodynamic impairment during progressive blood loss and warrant further validation.

Aim. To evaluate the impact of subanesthetic concentrations of xenon on the brain levels of GSK-3β, NF-κB, and Nrf2 in intact rats.

Materials and Methods. Male laboratory rats were randomly assigned to three groups (N=5 per group): the control group received inhalation of a nitrogen-oxygen gas mixture; the Xe-70 group received 70% xenon; and the Xe-35 group received 35% xenon. Following euthanasia, brain tissue samples were analyzed using Western blotting and densitometric quantification to assess levels of phosphorylated GSK-3β, NF-κB, and Nrf2. Results. Inhalation of xenon-oxygen mixtures led to a statistically significant increase in phosphorylated GSK-3β levels in both the Xe-70 group (95% CI: 593,723–1,018,826; P=0.0001; R=0.72) and the Xe-35 group (95% CI: 458,413–872,807; P=0.0001; R=0.80), compared with controls. Xenon exposure also resulted in a significant reduction in NF-κB levels in the Xe-70 (95% CI: 205,138–601,617; P=0.0005; R=0.95) and Xe-35 (95% CI: 217,700–608,462; P=0.0003; R=0.95) groups. Furthermore, Nrf2 protein expression was significantly elevated in the Xe-35 group compared to controls (95% CI: 260,926–692,532; P=0.0002; R=0.91).

Conclusion. Subanesthetic xenon concentrations exert a significant modulatory effect on GSK-3β, NF-κB, and Nrf2 expression in the brain tissue of intact rats.

The high incidence of postoperative cognitive dysfunction in children undergoing cardiac surgery underscores the urgent need for effective neuroprotective strategies.

Aim. To examine the effects of hypoxia and interleukin-6 (IL-6) on the expression of claudin-5, occludin-1, and interleukin-1 (IL-1) and IL-6 receptors in neurovascular unit (NVU) cells.

Materials and methods. An in vitro NVU model comprising neurons, astrocytes, and endothelial cells was established. The cells were cultured under normoxic and hypoxic conditions with oxygen concentrations of 15%, 10%, 7%, and 5%. The cultures were also treated with patient-derived sera containing high or low levels of IL-6. All incubations were conducted under normothermic conditions for 30 minutes. Injury marker expression was then assessed using fluorescence analysis.

Results. Significant reductions in claudin-5 fluorescence intensity were observed at oxygen levels of 10% and below (15.2 vs. 34.3 in controls, P=0.0105). Hypoxia did not affect occludin-1 expression. IL-1 receptor fluorescence intensity increased under 7% and 5% oxygen conditions (12.2 and 12.9 versus 9.9 in the control group, P=0.0105), while IL-6 receptor expression remained unchanged. In both normoxic and hypoxic conditions, adding patient sera significantly altered marker expression; hypoxia enhanced these effects. Sera with the highest IL-6 levels induced the most pronounced reduction in injury marker fluorescence.

Conclusion. IL-6 had a more significant impact on injury marker expression in NVU cells than hypoxia did. Hypoxic conditions with oxygen concentrations down to 10% did not affect marker expression

This study aimed to identify neutrophil membrane characteristics that could serve as clinical biomarkers for the development of infectious complications in newborns.

Materials and Methods. Neutrophils isolated from healthy donors were used as a model system. The cells were incubated with plasma samples (S) isolated from blood of newborns categorized into three groups: apparently healthy (normal) (NS) (N=6), with localized infection (LIS) (N=7), and with generalized infection (GIS) (N=8). We assessed cellular morphology and membrane roughness before and after stimulation with phorbol 12-myristate 13-acetate (PMA) using fluorescence and atomic force microscopy. We quantified nuclear and membrane surface areas, the intensity of neutrophil extracellular trap (NET) formation, and membrane arithmetic average roughness (Ra).

Results. A standardized protocol for neutrophil preparation and evaluation was developed. Optimal incubation conditions were established; 1% bovine serum albumin (BSA) yielded minimal background activation. Dose-dependent activation of neutrophils by PMA was observed in the presence of 1% plasma. PMA stimulation significantly increased nuclear area (P0.001), membrane area (P0.001), and Ra (P0.001), regardless of plasma sample group. The most significant changes occurred in neutrophils incubated with plasma from the GIS group. Generalized infection was associated with enhanced NET activation, which may contribute to the pathogenesis of thrombotic complications in neonatal sepsis.

Conclusion. Microscopy-based neutrophil characteristics are promising biomarkers for evaluating infection including sepsis in newborns.

The issue of sepsis has been discussed extensively in the medical and scientific community for decades. However, a unified understanding of the biological nature of this condition has yet to be established.

Aim. To provide a structured review of the key concepts commonly used in clinical practice and in the scientific literature related to sepsis.

Materials and Methods. A review of the scientific literature combined with the authors' professional experience.

Results. From a methodological perspective, it is suggested to conceptualize sepsis as a pathological condition due to generalized suppurative process. In this case, typical sepsis and septic shock are proposed to be considered two pathogenically separate, independently developing anatomo-clinical forms of sepsis.

Conclusion. It is proposed to consider as sepsis only conditions associated with pathogens that are not capable of causing purulent inflammation. Non–purulent conditions not associated with pathogens of purulent infections are considered as generalization of bacterial, viral, protozoal, fungal diseases that may acquire toxic and especially toxic clinical forms designated as bacterial-toxic, or infectious-toxic (but not septic) shock. Typical sepsis and septic shock are proposed to be considered as independently developing clinical and anatomical forms of sepsis rather than the sequentially developing stages of the pathological condition.