title: Effect of the dose volume of perfluorocarbon when starting partial liquid ventilation.
abstract: OBJECTIVE
  Very preterm neonates are prone to brain injury if cerebral blood flow fluctuates. Partial liquid ventilation (PLV) may benefit any lung disease but giving 30 mL/kg of perfluorocarbon when starting PLV increases cortical cerebral blood flow velocity. We aimed to determine if varying the initial dose of perfluorocarbon alters the effect on cerebral blood flow velocity when starting PLV.
  
  
  METHODS
  In this randomised, controlled trial with historical comparison 24 preterm lambs received one of three loading doses of intratracheal perfluorocarbon liquid over 20 min when starting PLV: 20, 30 or 40 mL/kg. Data on respiratory mechanics, haemodynamics and cerebral blood flow velocity, measured with laser Doppler, were collected continuously for 30 min from the start of dosing.
  
  
  RESULTS
  Cortical cerebral blood flow velocity increased over time in all three groups (two-way ANOVA, P= 0.007). There was no difference between groups (two-way ANOVA, P= 0.26). There was no difference between groups in cortical cerebral blood flow velocity variability (P= 0.68), blood pressure (P= 0.96) or heart rate (P= 0.46). The was no statistically significant difference in PaCO(2) between groups measured at baseline and at 30 min after starting PLV (P= 0.51).
  
  
  CONCLUSIONS
  Cortical cerebral blood flow velocity and its variability are not affected by varying doses of tracheal perfluorocarbon (20, 30 or 40 mL/kg) at the start of PLV in preterm lambs.
authors.affiliation: Grantley Stable Neonatal Unit, Perinatal Research Centre, Royal Brisbane and Women's Hospital, Herston, Queensland 4029, Australia. Mark_Davies@health.qld.gov.au
authors.forename: Mark W
authors.initials: MW
authors.lastname: Davies
authors.forename: Kimble R
authors.initials: KR
authors.lastname: Dunster
authors.forename: Kathy
authors.initials: K
authors.lastname: Wilson
authors.forename: Paul B
authors.initials: PB
authors.lastname: Colditz
mesh_terms: D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002540:Cerebral Cortex / Q000098:blood supply; D004305:Dose-Response Relationship, Drug; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage* / Q000494:pharmacology*; D006801:Humans; D007231:Infant, Newborn; D021061:Liquid Ventilation / Q000379:methods*; D008297:Male; D047928:Premature Birth; D012129:Respiratory Function Tests
chemical_list: D005466:Fluorocarbons