title: Evaluation of tissue saturation as a noninvasive measure of mixed venous saturation in children.
abstract: BACKGROUND
  Mixed venous saturation (S & OV0456;o2) is an important measurement that helps guide the care of critically ill patients. Invasive S & OV0456;o2 assessment in infants and children is often avoided because of the inherent risks. A noninvasive tissue saturation (S to 2) monitor has recently been developed that uses near-infrared spectroscopy to measure oxyhemoglobin saturation in muscle. In adult and animal studies, S to 2 correlated with oxygen delivery and S & OV0456;o2. There has been no evaluation in pediatric patients.
  
  
  OBJECTIVE
  To evaluate tissue saturation as a noninvasive measure of mixed venous saturation in children.
  
  
  METHODS
  A prospective observational study.
  
  
  METHODS
  Catheterization laboratory in a tertiary care children's medical center.
  
  
  METHODS
  We studied 98 children (49 without intracardiac mixing and 49 with intracardiac mixing) <or=12 yrs of age who underwent cardiac catheterization. Under general anesthesia, we compared S to 2 measured over the deltoid muscle with superior vena cava saturation in both groups and S to 2 with pulmonary artery saturation in patients without intracardiac mixing. Paired measurements were analyzed for bias, precision, and correlation via Bland-Altman plot and linear regression.
  
  
  RESULTS
  No meaningful correlation was found between S to 2 and superior vena cava saturation or pulmonary artery saturation. Bland-Altman analyses of S to 2 with superior vena cava saturation yielded bias values of -6.67 +/- 37.33% in patients with intracardiac mixing and -0.82 +/- 41.31% in patients without mixing. Bland-Altman analysis of S to 2 with pulmonary artery saturation yielded a bias of 3.61 +/- 41.32% in patients without mixing. Differences between noninvasive and invasive measurements were greatest in smaller children.
  
  
  CONCLUSIONS
  Noninvasive tissue saturation over the deltoid does not correlate with S & OV0456;o2 in children. It is possible that more precise probe spacing, coupled with optimal muscle-mass location, could result in more accurate measures in future investigations.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine and Division of Cardiology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Levy
authors.forename: Whitney B
authors.initials: WB
authors.lastname: Stern
authors.forename: Kimberly I
authors.initials: KI
authors.lastname: Minger
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Montenegro
authors.forename: Chitra
authors.initials: C
authors.lastname: Ravishankar
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Rome
authors.forename: Susan C
authors.initials: SC
authors.lastname: Nicolson
authors.forename: David R
authors.initials: DR
authors.lastname: Jobes
mesh_terms: D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D016638:Critical Illness; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008991:Monitoring, Physiologic / Q000379:methods*; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D011446:Prospective Studies; D011651:Pulmonary Artery; D019265:Spectroscopy, Near-Infrared; D014684:Venae Cavae
chemical_list: D010100:Oxygen