title: Regional tissue oxygen saturation: comparability and reproducibility of different devices.
abstract: Comparability and reproducibility of different near-infrared spectroscopy devices measuring regional tissue oxygen saturation remain poor. Aim of the present study was to compare values and reproducibility of cerebral∕peripheral "tissue-oxygenation-index" (TOI; NIRO 300, Hamamatsu(®), Japan) with cerebral∕peripheral "regional-oxygen-saturation" (rSO; INVOS5100, Somanetics(®), USA), and to analyze the influence of quality criteria.
  
  
  METHODS
  cTOI and crSO2 were measured on the left forehead, pTOI and prSO2 were measured on the left calf. To analyse reproducibility, optodes were reapplied five times. A quality criterion was introduced for cTOI, crSO2 and prSO2. For pTOI quality criteria were introduced in combination with a venous occlusion technique.
  
  
  RESULTS
  Cerebral measurements were performed in 37 neonates. cTOI (72.7+∕-6.2%) was lower than crSO2 (83.3+∕-5.8%) (p < 0.001). The mean difference between cTOI and crSO2 was 10%. Mean standard deviations of cTOI and crSO2 were similar (cTOI: 4.9+∕-3.6; crSO2: 4.5+∕-2.6). Peripheral measurements were performed in 39 neonates. pTOI (66.0+∕-7.9%) was lower than prSO2 (82.0+∕-7.0%)(p < 0.001). The mean difference between pTOI and prSO2 was 15%. Mean standard deviations of pTOI (3.7+∕-2.6%) were lower than of prSO2 (5.0+∕-3.0%) (p = 0.047).
  
  
  CONCLUSIONS
  TOI values were significantly lower than rSO2 values, in cerebral and peripheral measurements. Reproducibility was higher for pTOI than for prSO2.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Research Unit for Cerebral Development and Oximetry Research, Medical University of Graz, Auenbruggerplatz 30, Styria, Austria.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Pocivalnik
authors.forename: Gerhard
authors.initials: G
authors.lastname: Pichler
authors.forename: Heinz
authors.initials: H
authors.lastname: Zotter
authors.forename: Nina
authors.initials: N
authors.lastname: Tax
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Müller
authors.forename: Berndt
authors.initials: B
authors.lastname: Urlesberger
mesh_terms: D002560:Cerebrovascular Circulation / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007231:Infant, Newborn; D010092:Oximetry / Q000295:instrumentation*; D010100:Oxygen / Q000097:blood*; D010783:Photometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation*
chemical_list: D010100:Oxygen