Changes in the capillary plasma cell-free layer during a crystalloid or colloid fluid challenge in healthy volunteers
Abstract
Background: Hemodilution by fluid loading is frequently used to optimize patient hemodynamics, but might have disturbing effects on microvascular integrity and function. An increase in the microvascular red blood cell-free layer, the so-called perfusion boundary region (PBR), has been shown to be inversely related to glycocalyx thickness. This study investigated whether different types of fluids have distinct effects on the PBR and microvascular perfusion in healthy subjects.
Methods: Eighteen healthy volunteers, aged 18 to 85 years, were exposed to two fluid boluses according to a fixed protocol over a 60-minute time period. Subjects first received a crystalloid fluid infusion, followed by a colloid infusion. During fluid infusion, the PBR and perfused vessel density (PVD) were measured at different time points using a sublingual microvascular imaging device.
Results: Crystalloid infusion only increased PBR for vessels with a diameter of 10-19 μm (2.46 ± 0.33 μm, P=0.008) immediately after infusion, and for vessels with a diameter of 5-9 (1.13 ± 0.10 μm; P=0.04) and 10-19 μm (2.44 ± 0.43 μm; P=0.009) 15 minutes after infusion. Colloid infusion did not alter PBR for any vessel at any time point. Fluid infusion did not alter microvascular perfusion.
Conclusions: In this small, healthy volunteer study we found only a small effect of a crystalloid bolus on the perfused boundary region, while microcirculatory perfusion remained unaltered.
Citation: Stens J, Verstoep N, Schieveld BRN, Groepenhoff F, Hering JP, Boer C. Changes in the capillary plasma cell-free layer during a crystalloid or colloid fluid challenge in healthy volunteers. Chapter 5 in: Stens J. Hemodynamic monitoring and goal-directed fluid management in abdominal surgery. PhD thesis, Vrije Universiteit Amsterdam; 2024. https://doi.org/10.5463/thesis.417