Background: The consequences of acute normovolemic hemodilution (ANH) following different types of fluids on the different components of the glycocalyx and on vascular barrier permeability (VBP) remain unknown.
Aim: To investigate whether the microcirculatory disruption and glycocalyx shedding induced by ANH alters VBP and whether this is affected by the composition and volume of the resuscitation fluid.
Methods: Anesthetized Wistar albino rats (n = 24) underwent stepwise ANH at hematocrit levels of 35%, 25%, 20%, and 15% induced by the exchange of blood with 6% balanced hydroxyethyl starch (1:1), balanced crystalloid (1:3), and normal saline (NS) (1:3). Glycocalyx-shed products were measured at each level of hemodilution. VBP was reflected in the decay of fluorescence dyes of different molecular size and their plasma retention ratios. Edema was assessed by measuring organ water content and muscle microcirculation by hand-held videomicroscopy.
Results: NS caused increased degradation of heparan sulfate and hyaluronan compared with the control group (P = 0.003, P = 0.004, respectively). Neither VBP nor tissue edema was affected by the fluid used. The total and perfused vessel densities within the microcirculation of muscle tissue decreased at hematocrit 15% in the balanced crystalloid (P = 0.02) and NS groups only (P < 0.0001, P = 0.0003, respectively) compared with baseline.
Conclusion: Balanced colloid solution preserved the glycocalyx layer better than balanced and unbalanced crystalloid solutions while maintaining the microcirculatory function associated with an improved total intravascular volume. Among the fluids tested, NS caused the most microcirculatory alterations. While ANH caused the degradation of glycocalyx components regardless of fluid, it did not disrupt the vascular barrier as indicated by macromolecular leakage.
Relevance for patients: The results of this study provide insight into the choice of fluid for optimal perioperative fluid management and the consequences of fluid type on the vascular barrier, glycocalyx, and microcirculation.
1 Department of Adult Intensive Care, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
2 Department of Translational Physiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
3 INSERM U1116, University of Lorraine, Vandoeuvre-Les-Nancy, France
4 Department of Anesthesiology and Critical Care Medicine, University Hospital of Nancy, France
5 Fresenius Kabi Deutschland GmbH, Bad Homburg, Germany
Dr. Bülent Ergin
Laboratory of Translational Intensive Care, Department of Adult Intensive Care, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands, Doctor Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
Department of Pharmaceutics, Utrecht University, the Netherlands
Department of Pharmaceutics, Jiaxing University Medical College, Zhejiang, China