title: High mixed venous oxygen saturation levels do not exclude fluid responsiveness in critically ill septic patients.
abstract: BACKGROUND
  The aim of this study was to determine whether the degree of fluid responsiveness in critically ill septic patients is related to baseline mixed venous oxygen saturation (SvO2) levels. We also sought to define whether fluid responsiveness would be less likely in the presence of a high SvO2 (>70%).
  
  
  METHODS
  This observational study was conducted in a 32-bed university hospital medicosurgical ICU. The hemodynamic response to a fluid challenge was evaluated in 65 critically ill patients with severe sepsis. Patients were divided into two groups (responders and nonresponders) according to their cardiac index (CI) response to the challenge (>10% or <10%).
  
  
  RESULTS
  Of the 65 patients, 34 (52%) were fluid responders. Baseline SvO2, CI, heart rate (HR) and mean arterial pressure (MAP) were not statistically different between groups. The responders had lower pulmonary artery occlusion pressure (PAOP) and central venous pressure (CVP) at baseline than the nonresponders. After the fluid challenge, there were no differences between the two groups in MAP, CVP, PAOP or HR. There was no correlation between changes in CI or stroke volume index and baseline SvO2. Receiver operating characteristic analysis showed that SvO2 was not a predictor of fluid responsiveness.
  
  
  CONCLUSIONS
  The response of septic patients to a fluid challenge is independent of baseline SvO2. The presence of a high SvO2 does not necessarily exclude the need for further fluid administration.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Velissaris
authors.forename: Charalampos
authors.initials: C
authors.lastname: Pierrakos
authors.forename: Sabino
authors.initials: S
authors.lastname: Scolletta
authors.forename: Daniel
authors.initials: D
authors.lastname: De Backer
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Vincent
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D002302:Cardiac Output; D002496:Central Venous Pressure; D016638:Critical Illness; D005440:Fluid Therapy; D006339:Heart Rate; D006801:Humans; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D012189:Retrospective Studies; D018805:Sepsis / Q000097:blood* / Q000503:physiopathology / Q000628:therapy*; D014680:Veins
chemical_list: D010100:Oxygen