title: Sonographic evaluation of vascular pulmonary reactivity following oxygen administration in fetuses with normal lung development.
abstract: OBJECTIVE
  This study aimed to establish nomograms for sonographic assessment of fetal pulmonary vascular reactivity following maternal hyperoxygenation.
  
  
  METHODS
  Sixty-two healthy fetuses were assessed at four weekly intervals from 26 weeks onwards. Pulmonary reactivity was evaluated using Doppler ultrasound in the main pulmonary artery and in the first branch of this main pulmonary artery. The difference in pulsatility index (∆PI) during maternal inhalation of a mixture of room air and oxygen (9 L/min) for at least 10 min was expressed as a percentage. Nomograms were constructed, and Kaplan-Meier curves were used to express the occurrence of a reactive test (∆PI ≥ 20%) with advancing gestation.
  
  
  RESULTS
  In the first branch, linear regression analysis revealed a significant correlation of ∆PI (%) with gestational age (r(2) = 0.04, p = 0.0057). Large inter-individual and intra-individual variability was noted. The ∆PI (%) in the main pulmonary artery remained constant throughout gestation (6.62 ± 17.83%).
  
  
  CONCLUSIONS
  Vascular reactivity in the pulmonary circulation increases in the first branch of the pulmonary artery. Large individual variability is limiting its use as a management tool.
authors.affiliation: Fetal Medicine Unit, Department of Obstetrics and Gynecology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Philip
authors.initials: P
authors.lastname: DeKoninck
authors.forename: Paul
authors.initials: P
authors.lastname: Lewi
authors.forename: Elisa
authors.initials: E
authors.lastname: Done
authors.forename: Jute
authors.initials: J
authors.lastname: Richter
authors.forename: Léonardo
authors.initials: L
authors.lastname: Gucciardo
authors.forename: Tim
authors.initials: T
authors.lastname: Van Mieghem
authors.forename: Jan A
authors.initials: JA
authors.lastname: Deprest
mesh_terms: D005260:Female; D005333:Fetus / Q000098:blood supply* / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000502:physiology; D049451:Nomograms; D010100:Oxygen; D011247:Pregnancy; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging* / Q000502:physiology; D011652:Pulmonary Circulation; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal
chemical_list: D010100:Oxygen