title: Precision of cerebral oxygenation and hemoglobin concentration measurements in neonates measured by near-infrared spectroscopy.
abstract: OBJECTIVE
  One source of error with near-infrared spectroscopy (NIRS) is the assumption that the measured tissue is optically homogeneous. This is not always the case. Our aim is to assess the impact of tissue homogeneity (TH) on the precision of NIRS measurements in neonates.
  
  
  METHODS
  On 36 term and 27 preterm neonates at least five 1-min measurements are performed on each subject using the OxiplexTS. The sensor position is slightly changed before each measurement while assessing TH. The precision for cerebral tissue oxygenation saturation (StO(2)) and total hemoglobin concentration (tHb) are calculated by repeated measures analysis of variance.
  
  
  RESULTS
  The mean StO(2) is not significantly different between term and preterm infants. The mean tHb is significantly lower in preterm infants (p < 0.01). With increasing TH, the precision of StO(2) increase from 5.6 to 4.6% for preterm and from 11.0 to 2.0% for term infants; the precision of tHb increases from 10.1 to 7.5μM for preterm and from 16.4 to 3.5 μM for term infants. The precision for StO(2) is higher in term than in preterm infants. The precision for tHb shows no significant difference between the two groups.
  
  
  CONCLUSIONS
  The precision of NIRS measurements correlates with tissue homogeneity.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Zurich, Clinic of Neonatology, Frauenklinikstrasse 10, 8091 Zurich, Switzerland.
authors.forename: Sandra Jasminder
authors.initials: SJ
authors.lastname: Arri
authors.forename: Thomas
authors.initials: T
authors.lastname: Muehlemann
authors.forename: Martin
authors.initials: M
authors.lastname: Biallas
authors.forename: Hans Ulrich
authors.initials: HU
authors.lastname: Bucher
authors.forename: Martin
authors.initials: M
authors.lastname: Wolf
mesh_terms: D000704:Analysis of Variance; D002540:Cerebral Cortex / Q000098:blood supply; D006452:Hemoglobinometry / Q000379:methods* / Q000592:standards; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D010092:Oximetry / Q000379:methods* / Q000592:standards; D012044:Regression Analysis; D015203:Reproducibility of Results; D019265:Spectroscopy, Near-Infrared / Q000379:methods* / Q000592:standards
chemical_list: D006454:Hemoglobins