title: Combination of different noninvasive measuring techniques: a new approach to increase accuracy of peripheral near infrared spectroscopy.
abstract: One of the problems of near-infrared-spectroscopy (NIRS) measurements is low reproducibility. The aim of the present study was to introduce quality criteria to increase reproducibility of peripheral NIRS measurements. In a prospective cohort study in 40 neonates, repeated NIRS measurements were performed on the calf. During five "reapplication" periods (of NIRS optodes), five "measurements" (venous occlusions) were performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO2), fractional oxygen extraction (FOE), hemoglobin flow (Hbflow), oxygen delivery (DO2), and oxygen consumption (VO2) were assessed. Measurements with linear changes during venous occlusions were included for further analysis (first quality criterion: R(2)>0.95). The second quality criterion was the equation 0 < or = TOI-SvO2 < or = (SaO2-SvO2)x0.2. Variance components and mean standard deviations were analyzed after introduction of the quality criteria. Variance components of reapplication and measurement decreased after introduction of the second quality criterion (TOI: 46.6-35.0%, SvO2: 76.8-38.2%, FOE: 73.1-37.5%, Hbflow: 70.3-51.9%, DO2: 71.5-52.7%, and VO2: 70.9-63.8%). Mean standard deviations of TOI (6.6+/-3.0 to 4.7+/-3.2%), SvO2 (11.1+/-4.8 to 5.7+/-3.9%), FOE (11.3+/-4.8 to 5.9+/-4.0%), Hbflow (4.3+/-2.0 to 2.9+/-1.6 micromol100 mLmin), and DO2 (17.8+/-7.6 to 11.4+/-6.2 micromol100 mLmin) decreased significantly, too. Only 12% of measurements fulfilled both quality criteria. With the introduction of two quality criteria, test-retest variability of peripheral NIRS measurements decreased significantly and reproducibility increased significantly.
authors.affiliation: Medical University of Graz, Department of Pediatrics, Division of Neonatology, Auenbruggerplatz 30, 8036 Graz, Austria. pichler.gerhard@klinikum-graz.at
authors.forename: Gerhard
authors.initials: G
authors.lastname: Pichler
authors.forename: Karin
authors.initials: K
authors.lastname: Grossauer
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Peichl
authors.forename: Andrea
authors.initials: A
authors.lastname: Gaster
authors.forename: Andrea
authors.initials: A
authors.lastname: Berghold
authors.forename: Gerold
authors.initials: G
authors.lastname: Schwantzer
authors.forename: Heinz
authors.initials: H
authors.lastname: Zotter
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Müller
authors.forename: Berndt
authors.initials: B
authors.lastname: Urlesberger
mesh_terms: D000465:Algorithms; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism*; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D010100:Oxygen