Effect of the dose volume of perfluorocarbon when starting partial liquid ventilation

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.