Microcirculatory response to fluid challenge: should we prefer balanced colloids to rebalance tissue perfusion?

Abstract

Introduction Fluid resuscitation should improve tissue oxygenation in hypovolemia, besides restoring macrohemodynamic stability [1]. We evaluated the microvascular response to fluid challenge with different colloid solutions and its relation to macrohemodynamics. Methods An observational study of patients receiving a fluid challenge (500 ml colloids in 30 minutes) according to the attending physician's decision. Before and after the infusion, sublingual microcirculation was evaluated with sidestream dark-field imaging (Microscan; Microvision Medical, Amsterdam, the Netherlands). Microvascular flow and density were assessed for small vessels [2]. The cardiac index (CI), intrathoracic blood volume index (ITBVI) and extravascular lung water index (ELWI) were measured in seven patients with PiCCO2 (Pulsion Medical System, Munich, Germany). Results Ten patients (two sepsis, four trauma, three intracranial bleeding, one post surgery) received either saline-based hydroxyethyl starch (HES) 130/0.4 (Amidolite; B.BraunSpA; n = 5) or balanced HES 130/0.42 (Tetraspan; B.BraunSpA; n = 5). The CI (P = 0.02) and ITBVI (P = 0.07) tended to increase, the EVLWI did not change. Microvascular flow and density improved in the whole sample. No correlation was found between macro-circulatory and micro-circulatory parameters. Balanced HES led to a greater increase in capillary density than NaCl HES (Figure 1). Conclusion Balanced HES may be more eficacious than saline-based HES in recruiting the microcirculation, thereby improving tissue O 2 delivery. (Graph Presented).