Similar Microcirculatory Alterations in Patients with Normodynamic and Hyperdynamic Septic Shock

Abstract

RATIONALE: In normodynamic septic shock, the quantitative assessment of sublingual microcirculation has shown decreases in perfused vascular density and red blood cell velocity. However, no studies have been performed in hyperdynamic septic shock. OBJECTIVES: To characterize the microcirculatory patterns and rule out the presence of fast red blood cell velocity in patients with hyperdynamic septic shock. METHODS: We prospectively evaluated the sublingual microcirculation in healthy volunteers (n = 20) and in patients with hyperdynamic (n = 20) and normodynamic (n = 20) septic shock. Hyperdynamic septic shock was defined by a cardiac index >4.0 L/min/m(2). The microcirculation was assessed with sidestream dark field imaging and AVA 3.0 software. MEASUREMENTS AND MAIN RESULTS: There were no differences in perfused vascular density, proportion of perfused vessels, or microvascular flow index between patients with hyperdynamic and normodynamic septic shock, but these variables were reduced compared with those of healthy volunteers, A similar pattern was observed in red blood cell velocity (912 ± 291, 968 ± 204, and 1303 ± 120 μm/s, respectively; P < 0.0001) and its coefficient of variation. In both types of septic shock, no microvessel had a red blood cell velocity higher than the 100th percentile value for healthy volunteers. CONCLUSIONS: Patients with hyperdynamic septic shock showed microcirculatory alterations similar to those of patients with normal cardiac output. Both groups of patients had reduced perfused vascular density and red blood cell velocity and increased flow heterogeneity compared with that of healthy subjects. Fast red blood cell velocity was not found, even in patients with high cardiac output. These results support the conclusion that microcirculatory function is frequently dissociated from systemic hemodynamic derangements in septic shock.