Comparison of 6% hydroxyethyl starch 130/0.4 and saline solution for resuscitation of the microcirculation during the early goal-directed therapy of septic patients.

PURPOSE: The aim of this study was to show that 6% hydroxyethyl starch (HES) 130/0.4 achieves a better resuscitation of the microcirculation than normal saline solution (SS), during early goal-directed therapy (EGDT) in septic patients. MATERIALS AND METHODS: Patients with severe sepsis were randomized for EGDT with 6% HES 130/0.4 (n = 9) or SS (n = 11). Sublingual microcirculation was evaluated by sidestream dark field imaging 24 hours after the beginning of EGDT. RESULTS: On admission, there were no differences in Sequential Organ Failure Assessment score, mean arterial pressure, lactate, or central venous oxygen saturation. After 24 hours, no difference arose in those parameters. Sublingual capillary density was similar in both groups (21 ± 8 versus 20 ± 3 vessels/mm(2)); but capillary microvascular flow index, percent of perfused capillaries, and perfused capillary density were higher in 6% HES 130/0.4 (2.5 ± 0.5 versus 1.6 ± 0.7, 84 ± 15 versus 53 ± 26%, and 19 ± 6 versus 11 ± 5 vessels/mm(2), respectively, P < .005). CONCLUSIONS: Fluid resuscitation with 6% HES 130/0.4 may have advantages over SS to improve sublingual microcirculation. A greater number of patients would be necessary to confirm these findings.

Increasing arterial blood pressure with norepinephrine does not improve microcirculatory blood flow: a prospective study.

INTRODUCTION: Our goal was to assess the effects of titration of a norepinephrine infusion to increasing levels of mean arterial pressure (MAP) on sublingual microcirculation. METHODS: Twenty septic shock patients were prospectively studied in two teaching intensive care units. The patients were mechanically ventilated and required norepinephrine to maintain a mean arterial pressure (MAP) of 65 mmHg. We measured systemic hemodynamics, oxygen transport and consumption (DO2 and VO2), lactate, albumin-corrected anion gap, and gastric intramucosal-arterial PCO2 difference (DeltaPCO2). Sublingual microcirculation was evaluated by sidestream darkfield (SDF) imaging. After basal measurements at a MAP of 65 mmHg, norepinephrine was titrated to reach a MAP of 75 mmHg, and then to 85 mmHg. Data were analyzed using repeated measurements ANOVA and Dunnett test. Linear trends between the different variables and increasing levels of MAP were calculated. RESULTS: Increasing doses of norepinephrine reached the target values of MAP. The cardiac index, pulmonary pressures, systemic vascular resistance, and left and right ventricular stroke work indexes increased as norepinephrine infusion was augmented. Heart rate, DO2 and VO2, lactate, albumin-corrected anion gap, and DeltaPCO2 remained unchanged. There were no changes in sublingual capillary microvascular flow index (2.1 +/- 0.7, 2.2 +/- 0.7, 2.0 +/- 0.8) and the percent of perfused capillaries (72 +/- 26, 71 +/- 27, 67 +/- 32%) for MAP values of 65, 75, and 85 mmHg, respectively. There was, however, a trend to decreased capillary perfused density (18 +/- 10,17 +/- 10,14 +/- 2 vessels/mm2, respectively, ANOVA P = 0.09, linear trend P = 0.045). In addition, the changes of perfused capillary density at increasing MAP were inversely correlated with the basal perfused capillary density (R2 = 0.95, P < 0.0001). CONCLUSIONS: Patients with septic shock showed severe sublingual microcirculatory alterations that failed to improve with the increases in MAP with norepinephrine. Nevertheless, there was a considerable interindividual variation. Our results suggest that the increase in MAP above 65 mmHg is not an adequate approach to improve microcirculatory perfusion and might be harmful in some patients.