title: Acceleration time-to-ejection time ratio in fetal pulmonary artery predicts the development of neonatal respiratory distress syndrome: a prospective cohort study.
abstract: OBJECTIVE
  This study investigates whether fetal pulmonary artery Doppler waveforms can predict the subsequent development of respiratory distress syndrome (RDS).
  
  
  METHODS
  A prospective cohort study was performed in women with impending preterm birth. Pulsatility index, resistance index, systolic-to-diastolic ratio, peak systolic velocity, and acceleration time-to-ejection time (At/Et) ratio were measured in the main pulmonary artery of fetus just before delivery.
  
  
  RESULTS
  Neonates who developed RDS (n = 11) had significantly lower gestational age at birth than those without RDS (n = 31; median: 28.7 [range: 24.7 to 34.9] versus 32.9 [range: 25.7 to 36.0] weeks; p = 0.003); there was no difference in antenatal corticosteroid administration. Pulmonary artery At/Et ratio was significantly higher in fetuses that developed RDS compared with those that did not (median: 0.37 [range: 0.26 to 0.41] versus median: 0.30 [range: 0.21 to 0.44]; p = 0.008). RDS prediction score (=a hundredfold At/Et ratio) is significantly associated with the subsequent development of RDS after controlling for gestational age by logistic regression analysis (odds ratio = 1.31, 95% confidence interval 1.05 to 1.63, p = 0.017).
  
  
  CONCLUSIONS
  An elevated At/Et ratio in the fetal pulmonary artery is independently associated with the development of RDS in preterm infants. These data suggest that fetal pulmonary artery Doppler velocimetry may provide a reliable noninvasive technique to evaluate fetal lung maturity, similar to the way in which middle cerebral artery Doppler has replaced amniocentesis for the assessment of fetal anemia.
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sun Min
authors.initials: SM
authors.lastname: Kim
authors.forename: Joong Shin
authors.initials: JS
authors.lastname: Park
authors.forename: Errol R
authors.initials: ER
authors.lastname: Norwitz
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Hwang
authors.forename: Hye Sim
authors.initials: HS
authors.lastname: Kang
authors.forename: Chan-Wook
authors.initials: CW
authors.lastname: Park
authors.forename: Jong Kwan
authors.initials: JK
authors.lastname: Jun
mesh_terms: D000328:Adult; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005333:Fetus / Q000098:blood supply*; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D007752:Obstetric Labor, Premature / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000196:embryology*; D012127:Respiratory Distress Syndrome, Newborn / Q000000981:diagnostic imaging / Q000196:embryology* / Q000503:physiopathology; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal / Q000379:methods*