title: Microvascular reactivity is altered early in patients with acute respiratory distress syndrome.
abstract: Acute respiratory distress syndrome (ARDS) is associated with vascular endothelial dysfunction. The resultant microvascular reactivity can be assessed non-invasively using near-infrared spectroscopy (NIRS) and a vascular occlusion test (VOT) and changes have been correlated with severity of organ dysfunction and mortality in other critically ill populations. We used NIRS to study the presence of microcirculatory alterations in patients with ARDS.
  
  
  
  We studied 27 healthy volunteers and 32 ARDS patients admitted to our intensive care department. NIRS measurements were performed within 24 h after diagnosis (Berlin definition). VOTs were performed by inflating an arm-cuff to a pressure greater than the systolic pressure for 3 min, followed by rapid deflation. The descending (Desc) and ascending (Asc) thenar muscle oxygen saturation (StO2) slopes were calculated. We compared data from volunteers with those from ARDS patients, from ARDS survivors and non-survivors, and from ARDS survivors who required <7 days ventilatory support (good evolution) with those who required >7 days support or died (poor evolution).
  
  
  
  ARDS patients had lower StO2 values [75(67-80) vs 79(76-81) %, p = 0.04] and Asc slopes [185(115-233) vs 258(216-306) %/min, p < 0.01] than healthy volunteers, but Desc slopes were similar. The Asc slope was lower in the patients with a poor evolution than in the other patients [121(90-209) vs 222(170-293) %/min, p < 0.01], and in the non-survivors than in the survivors [95(73-120) vs 212(165-252) %/min, p < 0.01].
  
  
  
  In ARDS patients, microvascular reactivity is altered early, and the changes are directly related to the severity of the disease. The ascending slope is the best determinant of outcome.
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, B-1070, Brussels, Belgium.
authors.forename: Diego
authors.initials: D
authors.lastname: Orbegozo Cortés
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, B-1070, Brussels, Belgium.
authors.forename: Lokmane
authors.initials: L
authors.lastname: Rahmania
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, B-1070, Brussels, Belgium.
authors.forename: Marian
authors.initials: M
authors.lastname: Irazabal
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, B-1070, Brussels, Belgium.
authors.forename: Carlos
authors.initials: C
authors.lastname: Santacruz
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, B-1070, Brussels, Belgium.
authors.forename: Vito
authors.initials: V
authors.lastname: Fontana
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, B-1070, Brussels, Belgium.
authors.forename: Daniel
authors.initials: D
authors.lastname: De Backer
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, B-1070, Brussels, Belgium.
authors.forename: Jacques
authors.initials: J
authors.lastname: Creteur
authors.affiliation: Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, B-1070, Brussels, Belgium. jlvincent@intensive.org.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Vincent
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation; D055806:Microvessels / Q000503:physiopathology*; D008875:Middle Aged; D011379:Prognosis; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy; D012720:Severity of Illness Index; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors; D034941:Upper Extremity / Q000098:blood supply*
keywords: Hypoxemia; Mechanical ventilation; Microcirculation; Prognosis; Reactive hyperemia