Quantitative assessment of the microcirculation in healthy volunteers and in patients with septic shock

Objective: The microcirculation of septic patients has been characterized only semiquantitatively. Our goal was to characterize the sublingual microcirculation in healthy volunteers and patients with septic shock quantitatively. Our hypotheses were that 1) hyperdynamic blood flow is absent in septic shock; 2) nonsurvivors show more severe alterations than survivors; and 3) quantitative and semiquantitative microcirculatory parameters have a similar performance. Design: Prospective, observational study. Setting: Teaching intensive care unit in a university-affiliated hospital. Subjects: Twenty-five normal volunteers and 25 patients with septic shock. Interventions: None. Measurements and Main Results: The sublingual microcirculation was evaluated by means of sidestream dark field imaging. Semiquantitative and quantitative microcirculatory parameters were determined through the use of applied software. Septic patients showed decreased perfused capillary density (13.2 +/- 4.4 mm/mm(2) vs. 16.6 +/- 1.6 mm/mm(2)), proportion of perfused capillaries (0.78 +/- 0.23 vs. 1.00 +/- 0.01), microvascular flow index (2.15 +/- 0.61 vs. 2.97 +/- 0.03), and red blood cell veloc Conclusions: The main characteristics of sublingual microcirculation in patients with septic shock are hypoperfusion and increased flow heterogeneity. Hyperdynamic microvascular blood flow was not found. Nonsurvivors showed more severe alterations than survivors. Quantitative and semiquantitative microcirculatory variables displayed similar behaviors. (Crit Care Med 2012; 40: 1443-1448)