title: Volume management in critically ill patients: New insights.
abstract: In order to turn a fluid challenge into a significant increase in stroke volume and cardiac output, 2 conditions must be met: 1) fluid infusion has to significantly increase cardiac preload and 2) the increase in cardiac preload has to induce a significant increase in stroke volume. In other words, a patient can be nonresponder to a fluid challenge because preload does not increase during fluid infusion or/and because the heart (more precisely, at least 1 of the ventricles) is operating on the flat portion of the Frank-Starling curve. Volumetric markers of cardiac preload are therefore useful for checking whether cardiac preload effectively increases during fluid infusion. If this is not the case, giving more fluid, using a venoconstricting agent (to avoid venous pooling), or reducing the intrathoracic pressure (to facilitate the increase in intrathoracic blood volume) may be useful for achieving increased cardiac preload. Arterial pulse pressure variation is useful for determining whether stroke volume can/will increase when preload does increase. If this is not the case, only an inotropic drug can improve cardiac output. Therefore, the best option for determining the usefulness of, and monitoring fluid therapy in critically ill patients is the combination of information provided by the static indicators of cardiac preload and arterial pulse pressure variation.
authors.affiliation: Anesthesia and Surgical ICU Heart Institute, Hospital das Clínicas, University of São Paulo-SP, Brazil.
authors.forename: Marcel Rezende
authors.initials: MR
authors.lastname: Lopes
authors.forename: José Otávio Costa
authors.initials: JO
authors.lastname: Auler
authors.forename: Frédéric
authors.initials: F
authors.lastname: Michard
mesh_terms: D015415:Biomarkers; D001794:Blood Pressure; D001810:Blood Volume; D001811:Blood Volume Determination / Q000379:methods*; D002302:Cardiac Output; D016638:Critical Illness; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D013318:Stroke Volume
chemical_list: D015415:Biomarkers