The effects of acute normovolemic and hypervolemic hemodilution on rats

Fluid applications to patients with unknown fluid status and intensive care unit form two types of hemodilution. In acute normovolemic hemodilution, only the effect of anemia is seen, whereas in acute hypervolemic hemodilution the tension of the vascular system along with anemia is also involved. In our study, we tried to understand normovolemic and hypervolemic hemodilution on kidney and systemic effects in a rat model. For this purpose, hematocrit 25% colloid (6% Hydroxy ethyl starch) was applied to animals in the normovolemic and hypervolemic hemodilution was created. Hemodynamic measurements were performed during the experiment and the parameters of routine biochemistry (lactate, urea, creatinine, bun), oxidative stress (malondialdehyde, hydroxyl, ischemia-modified albumin), inflammation (tumor necrosis factor alpha), glycocalyx injury (syndecan-1, sialic acid), atrial natriuretic peptide and catecholamines were evaluated. According to our findings,both hemodilution techniques caused an increase in hemolysis (free hemoglobin), systemic inflammation (TNF-a), oxidative stress (MDA), glycocalyx degradation (syndecan-1), ANP and catecholamine levels (epinephrine, norepinephrine). In addition, acute normovolemic hemodilution reduced blood pressure and caused kidney stress by affecting systemic hypoxia and renal function. However, in acute hypervolemic hemodilution, more fluid is needed to achieve target hematocrit. As a conclusion, fluid applications have negative effects on organs and tissues. However, if fluid administration is unavoidable, hypervolemic hemodilution with less damage is preferable.