title: Pulmonary circulation of fetal sheep with lung hyperplasia following tracheal occlusion.
abstract: OBJECTIVE
  To determine the alteration of blood flow velocity profile in the pulmonary arteries (PAs) of fetal sheep after tracheal occlusion (TO).
  
  
  METHODS
  Doppler ultrasound investigations of the PAs, the pulmonary trunk and the ductus arteriosus were performed weekly in nine ewes (gestational age 92-98 days, term 145 days) with singleton pregnancies after TO (n = 5) and in control fetuses (n = 4). Histological examinations with morphometry of pulmonary arterial vessels and of airways were performed in both groups.
  
  
  RESULTS
  In the control group the experiments lasted 38 +/- 6 days (mean +/- SD), and in the TO group 25 +/- 7 days. Relative lung weight was significantly higher in the TO group compared with the control group (14.5 +/- 3.4% and 4.0 +/- 0.5% of body weight). There were no significant differences in the Doppler parameters (pulsatility index, resistance index, the systolic peak, the diastolic minimum, time averaged maximum velocity) between groups. When the Doppler values of PAs in TO and control fetuses were combined, no significant differences between the left and right PA could be detected. The external diameter of peripheral PAs was significantly higher in the TO group as compared to control group (105.7 +/- 2.5 microm vs. 96.9 +/- 1.3 microm).
  
  
  CONCLUSIONS
  We found a threefold increase of fetal lung volume after TO without significant changes of blood flow velocity profiles in the PAs of fetal sheep.
authors.affiliation: Universitätsklinikum Hamburg-Eppendorf, Department of Obstetrics and Fetal Medicine, Hamburg, Germany. tchiriko@uke.uni-hamburg.de
authors.forename: M
authors.initials: M
authors.lastname: Tchirikov
authors.forename: K
authors.initials: K
authors.lastname: Hecher
authors.forename: J
authors.initials: J
authors.lastname: Deprest
authors.forename: E
authors.initials: E
authors.lastname: Verbeken
authors.forename: X
authors.initials: X
authors.lastname: Roubliova
authors.forename: H J
authors.initials: HJ
authors.lastname: Schröder
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D005260:Female; D006965:Hyperplasia; D008168:Lung / Q000000981:diagnostic imaging* / Q000196:embryology*; D008176:Lung Volume Measurements; D023421:Models, Animal; D011247:Pregnancy; D011651:Pulmonary Artery / Q000473:pathology; D011652:Pulmonary Circulation; D012756:Sheep; D014132:Trachea / Q000196:embryology; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal