title: Cerebral tissue oxygen saturation is associated with N-terminal probrain natriuretic peptide in preterm infants on their first day of life.
abstract: OBJECTIVE
  This prospective observational study investigated if N-terminal probrain natriuretic peptide (NT-proBNP), a cardiac biomarker, correlated with cerebral tissue oxygen saturation (crSO2) in preterm infants on their first day of life.
  
  
  METHODS
  Using near infrared spectroscopy (NIRS), crSO2 was measured on the right forehead of preterm infants for 24 h. We also recorded arterial oxygen saturation (SpO2 ) and calculated fractional tissue oxygen extraction (cFTOE) values. At the end of the NIRS measurement, blood was taken to analyse NT-proBNP. Mean values for the 24-h period were calculated for crSO2 , cFTOE, SpO2 and these values were correlated to NT-proBNP. An echocardiography was performed in all infants during the measurement period.
  
  
  RESULTS
  We analysed 35 preterm neonates (33 ± 2 weeks, 1965 ± 523 g). NIRS measurements started at 3 ± 1 h and blood samples were taken at 24 ± 5 h postnatal. Echocardiography showed an open ductus arteriosus in all infants. Mean NT-proBNP was 4978 ± 3566 pg/mL, crSO2 was 76 ± 8%, and cFTOE was 0.20 ± 0.08. NT-proBNP correlated negatively with crSO2 (r = -0.75; p ≤ 0.001) and positively with cFTOE (r = 0.731; p ≤ 0.001).
  
  
  CONCLUSIONS
  These results emphasise that crSO2 is influenced by cardiac function, in addition to oxygen consumption, arterial oxygen saturation and vascular resistance, and this can be measured by NT-proBNP.
authors.affiliation: Research Unit for Cerebral Development and Oximetry, Medical University of Graz, Graz, Austria; Research Unit for Neonatal Micro- and Macrocirculation, Medical University of Graz, Graz, Austria; Division of Neonatology, Department of Pediatrics, Medical University, Graz, Austria.
authors.forename: Corinna
authors.initials: C
authors.lastname: Binder-Heschl
authors.forename: Berndt
authors.initials: B
authors.lastname: Urlesberger
authors.forename: Martin
authors.initials: M
authors.lastname: Koestenberger
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schwaberger
authors.forename: Georg M
authors.initials: GM
authors.lastname: Schmölzer
authors.forename: Gerhard
authors.initials: G
authors.lastname: Pichler
mesh_terms: D015415:Biomarkers / Q000097:blood; D001921:Brain / Q000378:metabolism*; D005260:Female; D006334:Heart Function Tests; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood*; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010100:Oxygen / Q000378:metabolism*; D010446:Peptide Fragments / Q000097:blood*; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D010100:Oxygen
keywords: Cardiac biomarker; Cardiac output; Cerebral tissue oxygen saturation; N-terminal probrain natriuretic peptide; Preterm neonates