title: Central venous saturation is not an alternative to mixed venous saturation during cardiopulmonary bypass in coronary artery surgery patients.
abstract: BACKGROUND
  To evaluate the correlation and agreement between central venous saturation (ScvO(2)) and mixed venous saturation (SvO(2)) during cardiopulmonary bypass.
  
  
  METHODS
  Twenty-two consecutive patients scheduled for coronary artery surgery were prospectively included. Paired measurements of ScvO(2) and SvO(2) were performed 5 minutes after aortic cross-clamping, after each cardioplegia dose and after de-clamping of the aortic cross-clamp. ScvO(2) and SvO(2) were measured, respectively, by a fibreoptic catheter in the superior vena cava and on blood samples from the venous return line of the extracorporeal circuit, using a blood gas analyser
  
  
  RESULTS
  Ninety-five paired measurements of venous saturation were obtained. Correlation between the measurements was associated with an r = 0.55. The mean bias was 2.2 [Limits of agreement: -13.6%, +18%]. Changes in oxygen saturation over time showed an r = 0.4 and a mean bias of 0.2 [Limits of agreement: -17.9%, +18.3%]. Multivariate analysis identified the oxygen consumption index as the only factor explaining this variability.
  
  
  CONCLUSIONS
  Although mean biases between the measurements were low, limits of agreement were too large to provide a clinically acceptable estimation of SvO(2) by ScvO(2) in these conditions. Variations in regional oxygen consumption seem to be the main factor worsening the relationship.
authors.affiliation: Department of Anaesthesiology and Critical Care, Military Hospital, Tunis University, Tunis, Tunisia.
authors.forename: M S
authors.initials: MS
authors.lastname: Soussi
authors.forename: M A
authors.initials: MA
authors.lastname: Jebali
authors.forename: Y
authors.initials: Y
authors.lastname: Le Manach
authors.forename: M
authors.initials: M
authors.lastname: Nasri
authors.forename: B
authors.initials: B
authors.lastname: Zouari
authors.forename: S
authors.initials: S
authors.lastname: Chenik
authors.forename: M
authors.initials: M
authors.lastname: Ferjani
mesh_terms: D000368:Aged; D002314:Cardioplegic Solutions / Q000008:administration & dosage; D002315:Cardiopulmonary Bypass; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption
chemical_list: D002314:Cardioplegic Solutions; D010100:Oxygen