Liquid-assisted ventilation with perfluorochemical (PFC) has been beneficia
l in a variety of respiratory diseases in animals and humans. Although PFC
evaporation from the lungs is In part dependent on ventilation strategy and
positioning, guidelines for initial and replacement dosing are unclear. We
hypothesized that PFC evaporative loss over time is dependent on the size
of the initial dose. Juvenile rabbits (n = 18) were ventilated using consta
nt animal position and ventilator strategy. PFC (perflubron: LiquiVent(TM))
was instilled endotracheally, using four groups with initial doses of 2, 6
, 12, and 17 mL/kg. A previously described thermal detector that measures P
FC in expired gas was used to calculate loss rate, residual perflubron in t
he lung, and volume loss as a % of initial fill volume.
There was a significant dose, time, and dose-time interaction such that eva
porative loss was dependent on initial PFC volume and time after fill (P <
0.05). Evaporative loss rate decreased earlier at lower doses. The percenta
ge of initial volume lost to evaporation over time was Inversely related to
dose and could not be predicted by decreasing % PFC saturations, independe
nt of dose.
Evaporative loss should be considered to optimize both the application of P
FC to the lung and replacement dosing during partial liquid ventilation. Pe
diatr Pulmonol, 2000; 30:324-329, (C) 2000 Wiley-Liss. Inc.