title: Association between umbilical cord artery pCO₂ and the Apgar score; elevated levels of pCO₂ may be beneficial for neonatal vitality after moderate acidemia.
abstract: OBJECTIVE
  To determine the association between 5-min Apgar score and umbilical cord artery carbon dioxide tension (pCO₂).
  
  
  METHODS
  Observational study.
  
  
  METHODS
  European hospital labor wards.
  
  
  METHODS
  Data from 36,432 newborns ≥36 gestational weeks were obtained from three sources: two trials of monitoring with fetal electrocardiogram (the Swedish randomized controlled trial and the European Union Fetal ECG trial) and Mölndal Hospital data. After validation of the acid-base values, 25,806 5-min Apgar scores were available for analysis.
  
  
  METHODS
  Validation of the umbilical cord acid-base values was performed to obtain reliable data. 5-min Apgar score was regressed against cord artery pCO₂ in a polynomial multilevel model.
  
  
  METHODS
  Five-min Apgar score, umbilical cord pCO₂, pH, and base deficit.
  
  
  RESULTS
  Overall, a higher cord artery pCO₂ was found to be associated with lower 5-min Apgar scores. However, among newborns with moderate acidemia, lower umbilical cord artery pCO₂ (≤median pCO₂ for the specific cord artery pH) was associated with lower 5-min Apgar scores, with a relative risk of 2.0 (95% confidence interval: 1.4-2.8) for 5-min Apgar scores 0-6.
  
  
  CONCLUSIONS
  Metabolic acidosis affects the newborn's vitality more than respiratory acidosis. In addition, elevated levels of pCO₂ may be beneficial for fetuses with moderate acidemia, and thus cord artery pCO₂ is a factor that should be considered when assessing the compromised newborn.
authors.affiliation: Women and Children's Division, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway. gbirke@ous-hf.no
authors.forename: Grete A B
authors.initials: GA
authors.lastname: Kro
authors.forename: Branka M
authors.initials: BM
authors.lastname: Yli
authors.forename: Svein
authors.initials: S
authors.lastname: Rasmussen
authors.forename: Håkan
authors.initials: H
authors.lastname: Norèn
authors.forename: Isis
authors.initials: I
authors.lastname: Amer-Wåhlin
authors.forename: Karl G
authors.initials: KG
authors.lastname: Rosén
authors.forename: Babill
authors.initials: B
authors.lastname: Stray-Pedersen
authors.forename: Ola D
authors.initials: OD
authors.lastname: Saugstad
mesh_terms: D000138:Acidosis / Q000097:blood*; D001034:Apgar Score; D002245:Carbon Dioxide / Q000097:blood*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D014469:Umbilical Arteries / Q000737:chemistry*; D014471:Umbilical Veins / Q000737:chemistry
chemical_list: D002245:Carbon Dioxide