Perfluorocarbon dosing when starting partial liquid ventilation: haemodynamics and cerebral blood flow in preterm lambs.
BACKGROUND
Very preterm neonates can have severe lung disease and are prone to brain injury if cerebral blood flow fluctuates. Partial liquid ventilation (PLV) may benefit the lung disease, but it is unknown whether the administration of intratracheal perfluorocarbon when starting PLV affects haemodynamics or cerebral blood flow.


OBJECTIVE
To determine if haemodynamics or cerebral blood flow are affected in preterm lambs receiving a dose of perfluorocarbon when starting PLV.


METHODS
Sixteen preterm lambs were randomised to either PLV or conventional mechanical ventilation. An intratracheal loading dose of 30 ml/kg of perfluorocarbon liquid (PLV group) or air (sham group) was instilled over 20 min. Data were collected continuously for 30 min from the start of dosing.


RESULTS
Cortical cerebral blood flow velocity, measured continuously with laser Doppler, was increased in the PLV group during the administration of perfluorocarbon and immediately thereafter (p = 0.0026); the highest mean increase in the PLV group was 27%. There was no difference in cortical cerebral blood flow variability (p = 0.96). There was a slightly lower mean arterial blood pressure in the PLV group; the heart rate did not differ between groups. The PaCO(2) was higher in the PLV group at 30 min - the difference between groups was not statistically significant (difference between means = 5.5 mm Hg, 95% confidence interval -2.7 to 13.7).


CONCLUSIONS
Preterm lambs receiving a dose of tracheal perfluorocarbon at the start of PLV have an increased cortical cerebral blood flow velocity, but no change in cortical cerebral blood flow variability.
Grantley Stable Neonatal Unit, Royal Brisbane and Women's Hospital, Brisbane, Qld., Australia. Mark_Davies @ health.qld.gov.au
Mark W
MW
Davies
Kimble R
KR
Dunster
Kathy
K
Wilson
Paul B
PB
Colditz
D000818:Animals; D000831:Animals, Newborn; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D002540:Cerebral Cortex / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005466:Fluorocarbons / Q000494:pharmacology*; D005865:Gestational Age; D006339:Heart Rate / Q000187:drug effects; D017078:Laser-Doppler Flowmetry; D021061:Liquid Ventilation / Q000379:methods*; D008170:Lung Compliance / Q000187:drug effects; D008297:Male; D010100:Oxygen / Q000097:blood; D047928:Premature Birth; D012129:Respiratory Function Tests / Q000295:instrumentation; D012756:Sheep; D013990:Tidal Volume / Q000187:drug effects
D005466:Fluorocarbons; D002245:Carbon Dioxide; D010100:Oxygen