Dissociation between sublingual and gut microcirculation in the response to a fluid challenge in postoperative patients with abdominal sepsis

Background: This study was performed to compare intestinal and sublingual microcirculation and their response to a fluid challenge. Methods: Twenty-two septic patients in the first postoperative day of an intestinal surgery, in which an ostomy had been constructed, were evaluated both before and 20 min after a challenge of 10 mL/kg of 6% hydroxyethylstarch 130/0.4. We measured systemic hemodynamics and sublingual and intestinal microcirculation. Correlations between variables were determined through the Pearson test. Results: Fluid administration increased the cardiac index (2.6 +/- 0.5 vs. 3.3 +/- 1.0 L/min/m(2), P < 0.01) and mean arterial blood pressure (68 +/- 11 vs. 82 +/- 12 mm Hg, P < 0.0001). The sublingual but not the intestinal red blood cell (RBC) velocity increased (912 +/- 270 vs. 1,064 +/- 200 mu m/s, P < 0.002 and 679 +/- 379 vs. 747 +/- 419 mu m/s, P = 0.12, respectively). The sublingual and intestinal perfused vascular density (PVD) did not change significantly (15.2 +/- 2.9 vs. 16.1 +/- 1.2 mm/mm(2) and 12.3 +/- 6.7 vs. 13.0 +/- 6.7 mm/mm(2)). We found no correlation between the basal sublingual and intestinal RBC velocities or between their changes in response to the fluid challenge. The individual changes in sublingual RBC velocity correlated with those in cardiac index and basal RBC velocity. Individual changes in intestinal RBC velocity did not correlate with either the cardiac index modifications or the basal RBC velocity. The same pattern was observed with the sublingual and the intestinal PVDs. The sublingual RBC velocities and PVDs were similar between survivors and nonsurvivors. But the intestinal RBC velocities and PVDs were lower in nonsurvivors. Conclusions: In this series of postoperative septic patients, we found a dissociation between sublingual and intestinal microcirculation. The improvement in the sublingual microcirculation after fluid challenge was dependent on the basal state and the increase in cardiac output. In contrast, the intestinal microcirculation behaved as an isolated territory.