title: Effects of chest compressions on cardiovascular and cerebral hemodynamics in asphyxiated near-term lambs.
abstract: BACKGROUND
  Chest compressions (CC) and adrenaline administration are recommended in asphyxiated newborns with persistent bradycardia despite effective ventilation. The effects of CC on cerebral blood flow in newborns at birth are unknown. Our aim was to determine the effects of CC, with or without adrenaline administration, on the return of spontaneous circulation, carotid blood flow (CBF), and carotid arterial pressure (CAP) in asphyxiated near-term lambs.
  
  
  METHODS
  Asphyxia was induced in near-term lambs by clamping the umbilical cord and delaying ventilation onset until spontaneous circulation ceased. Lambs were then resuscitated by positive pressure ventilation along with CC followed by adrenaline administration. CAP and CBF were continuously recorded.
  
  
  RESULTS
  Mean CAP did not increase significantly during CC and only increased following adrenaline administration. CC did not increase mean CBF but increased CBF amplitude due to increased peak flow and the onset of retrograde flow during diastole. Adrenaline increased mean CBF from 1 ± 2 to 15 ± 5 ml/kg/min and abolished retrograde diastolic CBF, leading to the return in spontaneous circulation.
  
  
  CONCLUSIONS
  We conclude that CC with adrenaline administration was required to increase CBF and restore spontaneous circulation in asphyxiated lambs. Low CBF and retrograde diastolic CBF during CC indicate hypoperfusion to the brain.
authors.affiliation: The Ritchie Centre, Monash University, Melbourne, Australia.
authors.forename: Kristina S
authors.initials: KS
authors.lastname: Sobotka
authors.affiliation: The Ritchie Centre, Monash University, Melbourne, Australia.|Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia.
authors.forename: Graeme R
authors.initials: GR
authors.lastname: Polglase
authors.affiliation: Department of Pediatrics, Medical University, Graz, Austria.|Neonatal Research, Royal Women's Hospital, Melbourne, Australia.
authors.forename: Georg M
authors.identifier: http://orcid.org/0000-0001-9798-2415
authors.initials: GM
authors.lastname: Schmölzer
authors.affiliation: Neonatal Research, Royal Women's Hospital, Melbourne, Australia.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Davis
authors.affiliation: Department of Paediatrics, University Hospital of North Norway, Tromsø, Norway.|Paediatric Research Group, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
authors.forename: Claus
authors.initials: C
authors.lastname: Klingenberg
authors.affiliation: The Ritchie Centre, Monash University, Melbourne, Australia.|Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia.
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Hooper
mesh_terms: D000322:Adrenergic Agonists / Q000008:administration & dosage; D000818:Animals; D062186:Arterial Pressure; D001238:Asphyxia Neonatorum / Q000503:physiopathology / Q000628:therapy*; D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply*; D002339:Carotid Arteries / Q000187:drug effects / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D003131:Combined Modality Therapy; D004195:Disease Models, Animal; D004837:Epinephrine / Q000008:administration & dosage; D005260:Female; D005865:Gestational Age; D006336:Heart Massage; D006439:Hemodynamics / Q000187:drug effects; D011247:Pregnancy; D047928:Premature Birth; D020127:Recovery of Function; D012039:Regional Blood Flow; D012756:Sheep; D013997:Time Factors
chemical_list: D000322:Adrenergic Agonists; D004837:Epinephrine