INTRAVENOUS FLUIDS: Edited by Bertrand GuidetFluid therapy and the hypovolemic microcirculationGruartmoner, G.a; Mesquida, J.a; Ince, CanbAuthor Information aCritical Care Department, Hospital de Sabadell, Corporació Sanitària Parc Taulí, Universitat Autònoma de Barcelona, Sabadell, Spain bDepartment of Intensive Care, Erasmus MC University Hospital Rotterdam, Rotterdam, The Netherlands Correspondence to Can Ince, Department of Intensive Care, Erasmus MC, University Medical Center Rotterdam, Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands. Tel: +31651294101; e-mail: email@example.com Current Opinion in Critical Care: August 2015 - Volume 21 - Issue 4 - p 276–284 doi: 10.1097/MCC.0000000000000220 Buy Metrics Abstract Purpose of review In shock states, optimizing intravascular volume is crucial to promote an adequate oxygen delivery to the tissues. Our current practice in fluid management pivots on the Frank-Starling law of the heart, and the effects of fluids are measured according to the induced changes on stroke volume. The purpose of this review is to evaluate the boundaries of current macrohemodynamic approach to fluid administration, and to introduce the microcirculatory integration as a fundamental part of tissue perfusion monitoring. Recent findings Macrocirculatory changes induced by volume expansion are not always coupled to proportional changes in microcirculatory perfusion. Loss of hemodynamic coherence limits the value of guiding fluid therapy according to macrohemodynamics, and highlights the importance of evaluating the ultimate target of volume administration, the microcirculation. Summary Current approach to intravascular volume optimization is made from a macrohemodynamic perspective. However, several situations wherein macrocirculatory and microcirculatory coherence is lost have been described. Future clinical trials should explore the usefulness of integrating the microcirculatory evaluation in fluid optimization. Copyright © 2015 YEAR Wolters Kluwer Health, Inc. All rights reserved.