Параметры микроциркуляции в коже как диагностические маркеры нарушения центрального и церебрального кровообращения при геморрагическом шоке

Abstract

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 (LSCIbrain), and skin perfusion in the hindlimb (LSCIskin ) using laser speckle contrast imaging (LSCI). These measurements were repeated after 15% CBV loss (stage 2) and 35% CBV loss (stage 3). Cerebral (CVCbrain=LSCIbrain/MAP) and cutaneous (CVCskin=LSCIskin/MAP) vascular conductance indices were calculated. At stage 3, parameters of postocclusive 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 LSCIskin (P=0.003 vs SO), with no significant change in LSCIbrain. With further blood loss and a 43% reduction in LSCIskin (P<0.001 vs SO), LSCIbrain decreased by 14% (P<0.001 vs SO). These changes were accompanied by a sustained increase in CVCbrain (P<0.001 vs SO at stage 3), while CVCskin 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 LSCIskin, CVCskin, and CVCbrain. In HS, LSCIbrain correlated with the degree of LSCIskin 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 LSCIskin and MAP shifted from a moderate negative correlation at stage 1 to a strong positive correlation at stage 3. Conclusion. Skin microcirculation parameters (LSCIskin, CVCskin, 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.