title: Quantitative assessment of the microcirculation in healthy volunteers and in patients with septic shock.
abstract: 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.
  
  
  METHODS
  Prospective, observational study.
  
  
  METHODS
  Teaching intensive care unit in a university-affiliated hospital.
  
  
  METHODS
  Twenty-five normal volunteers and 25 patients with septic shock.
  
  
  METHODS
  None.
  
  
  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/mm² vs. 16.6±1.6 mm/mm²), 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 velocity (830±183 µm/sec vs. 1332±187 µm/sec) along with increased heterogeneity flow index (1.64±1.14 vs. 0.25±0.19) compared with controls. No differences were found in total capillary density (16.9±2.2 vs. 16.7±1.6). Only 4% of capillaries analyzed showed red blood cell velocities>75th percentile of the velocities of the normal volunteers. The nonsurvivors exhibited decreased perfused capillary density, proportion of perfused capillaries, and microvascular flow index along with increased heterogeneity flow index compared with the survivors. The correlations between microvascular flow index and proportion of perfused capillaries, total capillary density and number of grid-crossing capillaries, and red blood cell velocities and microvascular flow index gave high R values (0.92, 0.65, and 0.52, respectively; p<.0001 for all).
  
  
  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.
authors.affiliation: Servicio de Terapia Intensiva, Sanatorio Otamendi y Miroli, Buenos Aires, Argentina.
authors.forename: Vanina S Kanoore
authors.initials: VS
authors.lastname: Edul
authors.forename: Carolina
authors.initials: C
authors.lastname: Enrico
authors.forename: Bruno
authors.initials: B
authors.lastname: Laviolle
authors.forename: Alejandro Risso
authors.initials: AR
authors.lastname: Vazquez
authors.forename: Can
authors.initials: C
authors.lastname: Ince
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Dubin
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D002196:Capillaries / Q000502:physiology / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D009060:Mouth Floor / Q000098:blood supply; D011446:Prospective Studies; D012772:Shock, Septic / Q000401:mortality / Q000503:physiopathology*