title: Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping) improves systemic and cerebral oxygenation in preterm lambs.
abstract: BACKGROUND
  As measurement of arterial oxygen saturation (SpO2) is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known.
  
  
  OBJECTIVE
  We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs.
  
  
  METHODS
  Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2) were measured continuously in apnoeic preterm lambs (126±1 day gestation). Positive pressure ventilation was initiated either 1) prior to umbilical cord clamping, or 2) after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping.
  
  
  RESULTS
  Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5-6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping.
  
  
  CONCLUSIONS
  The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.
authors.affiliation: The Ritchie Centre, Monash Institute of Medical Research-Prince Henrys Institute, Clayton, Victoria; Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria.
authors.forename: Graeme R
authors.initials: GR
authors.lastname: Polglase
authors.affiliation: Newborn Research Centre, Royal Women's Hospital, Melbourne, Victoria.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Dawson
authors.affiliation: Department of Neonatology, Royal North Shore Hospital and University of Sydney, Sydney, New South Wales.
authors.forename: Martin
authors.initials: M
authors.lastname: Kluckow
authors.affiliation: Centre for Neonatal Research and Education, The University of Western Australia, Western Australia, Australia.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Gill
authors.affiliation: Newborn Research Centre, Royal Women's Hospital, Melbourne, Victoria.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Davis
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Arjan B
authors.initials: AB
authors.lastname: Te Pas
authors.affiliation: The Ritchie Centre, Monash Institute of Medical Research-Prince Henrys Institute, Clayton, Victoria; Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria.
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Crossley
authors.affiliation: The Ritchie Centre, Monash Institute of Medical Research-Prince Henrys Institute, Clayton, Victoria; Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria.
authors.forename: Annie
authors.initials: A
authors.lastname: McDougall
authors.affiliation: The Ritchie Centre, Monash Institute of Medical Research-Prince Henrys Institute, Clayton, Victoria; Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria.
authors.forename: Euan M
authors.initials: EM
authors.lastname: Wallace
authors.affiliation: The Ritchie Centre, Monash Institute of Medical Research-Prince Henrys Institute, Clayton, Victoria; Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria.
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Hooper
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D062186:Arterial Pressure / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003250:Constriction; D036861:Delivery, Obstetric / Q000379:methods*; D005260:Female; D023421:Models, Animal; D036801:Parturition / Q000502:physiology*; D012756:Sheep; D014470:Umbilical Cord / Q000502:physiology*; D014691:Ventilation / Q000379:methods*