A novel expiratory circuit for recovery of perfluorocarbon liquid during partial liquid ventilation

To determine whether perfluorocarbon liquid can be condensed from gases containing perfluorocarbon vapour and whether the amount recovered varies with background flow rate.

Bench-top experimental study in a neonatal laboratory.

The expiratory limb of a standard ventilator circuit set-up was mimicked, with the addition of a chilled water jacket (Liebig) condenser. Perfluorocarbon vapour was passed through the circuit at a number of flow rates.

Perfluorocarbon vapour was passed through the circuit and the percentage recovery of liquid measured. More than 60% of the perfluorocarbon vapour was recovered at all flow rates (1, 2, 5 and 10 l/min), with significantly higher recovery obtained (up to 74%) at low flow rates (1 l/min).

Using a simple condenser, more than 60% of perfluorocarbon liquid can be recovered without altering the function of an expiratory limb of a ventilator circuit.