Evaluation of the Microcirculation in Critically Ill Patients

Abstract: The first goal of therapies in critically ill patients is to improve tissue perfusion and oxygenation. Hemodynamic monitoring has long been limited to measure-ments of cardiac output and global oxygen delivery. The clinical introduction of hand-held vital microscopes in the late 1990s enabled the real-time, non-invasive, bedside ob-servation of blood flow in the microcirculation (vessels with diameter <100 µm), i.e. the real site of oxygen and nutrient exchange between blood and cells. Microcirculatory alter-ations have been described during sepsis and shock states and were associated with mor-tality. These can occur independently of systemic hemodynamic alterations. Sublingual videomicroscopy allowed evaluating the microvascular response to resuscitation proce-dures, including oxygen therapy, fluids, blood transfusions, vasopressors. Future re-search directions should be aimed to integrate microcirculatory monitoring with standard hemodynamic measurements and verify the utility of microcirculation as a therapeutic tar-get. Continuous technological developments are imperative to facilitate the introduction of sublingual videomicroscopy in the clinical practice.