title: Perinatal adaptive response of the adrenal and carotid blood flow in sheep fetuses subjected to total cord occlusion.
abstract: OBJECTIVE
  To investigate the perinatal adaptive response of the adrenal blood flow/adrenal fractional moving blood volume (AFMBV) and carotid blood flow (CBF), in sheep fetuses subjected to severe acute intrauterine hypoxia/asphyxia induced by total cord occlusion.
  
  
  METHODS
  Adrenal blood flow velocity, AFMBV and CBF were measured in 13 exteriorized fetal sheep; eight of them underwent total umbilical cord occlusion to induce severe acute hypoxia/asphyxia. Five lambs were used as sham controls. Middle adrenal artery pulsatility index (MAAPI) and mean velocity (MAAMV) were recorded with pulsed Doppler ultrasound. AFMBV was estimated using power Doppler ultrasound. CBF was recorded with a transonic flowmeter. In the neonatal period, after resuscitation all lambs were followed for a 4-hour period and AFMBV and CBF were recorded. Mean arterial blood pressure (MABP) and fetal heart rate were recorded continuously. Arterial cortisol levels were measured at the beginning and at the end of the fetal and neonatal periods.
  
  
  RESULTS
  Following the total cord occlusion, there was a significant reduction in the CBF, MABP, and heart rate and adrenal flow/AFMBV after 2, 4 and 5 min, respectively. Cortisol levels in the asphyctic lambs at the end of the cord occlusion were significantly lower than those in controls. After resuscitation, the asphyctic lambs showed increased AFMBV and cortisol levels, and reduced MABP as compared to control lambs. No differences were found in CBF, MAAPI and MAAMV. Thereafter, no differences were observed between the two groups in any of the studied parameters. At the end of the cord occlusion period, there was a significant correlation between AFMBV and MABP (r=0.69), between AFMBV and CBF (r =0.65) and between CBF and MABP (r=0.89).
  
  
  CONCLUSIONS
  During severe acute intrauterine hypoxia, the fetal lamb is able to maintain the blood flow to the brain and the adrenal gland for 3-5 min. Changes in the AFMBV and the CBF were highly correlated to the changes in MABP. Adrenal FMBV and cortisol levels were higher in lamb neonates exposed to severe intrauterine asphyxia.
authors.affiliation: Department of Obstetrics and Gynecology, University of Lund, Sweden. Edgar.Hernandez-Andrade@gyn.lu.se
authors.forename: Edgar
authors.initials: E
authors.lastname: Hernandez-Andrade
authors.forename: Lena
authors.initials: L
authors.lastname: Hellström-Westas
authors.forename: Kristina
authors.initials: K
authors.lastname: Thorngren-Jerneck
authors.forename: Tomas
authors.initials: T
authors.lastname: Jansson
authors.forename: Karina
authors.initials: K
authors.lastname: Liuba
authors.forename: Göran
authors.initials: G
authors.lastname: Lingman
authors.forename: Karel
authors.initials: K
authors.lastname: Marsál
authors.forename: Gylfi
authors.initials: G
authors.lastname: Oskarsson
authors.forename: Olof
authors.initials: O
authors.lastname: Werner
authors.forename: David
authors.initials: D
authors.lastname: Ley
mesh_terms: D000311:Adrenal Glands / Q000098:blood supply*; D000818:Animals; D001783:Blood Flow Velocity; D002339:Carotid Arteries / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005311:Fetal Hypoxia / Q000209:etiology / Q000503:physiopathology*; D005333:Fetus; D007511:Ischemia / Q000150:complications*; D012756:Sheep; D014470:Umbilical Cord / Q000098:blood supply*