Alveolar Permeability and Liquid Absorption during Partial Liquid Ventilation of Rats with Perflubron

We examined the effect of instilled perflubron (LiquiVent) on the transport properties of alveolar epithelium in anesthetized rats. Krebs-Ringer bicarbonate (1 to 4 ml) containing 125I-albumin, [3H]mannitol and [14C]sucrose was instilled into airspaces either alone (n = 29), or with 1 (n = 21) or 2 (n = 12) ml perflubron and sampled 30 min later. Absorption was deduced from the changes in 125I-albumin activity per unit volume in the airspace instillate, and changes in [3H]mannitol and [14C]sucrose activity per unit volume were used to evaluate the passive permeability of the alveolar–airway barrier. The rate of Ringer absorption depended on the volume instilled [0.38 (ml/h)/ml Ringer]. Perflubron (1 or 2 ml) increased Ringer absorption by 0.26 (p < 0.001) and 0.19 ml/h (p < 0.05), respectively. However, 2 ml perflubron increased absorption less than did the same additional volume of Ringer (p < 0.001). The passive permeability of the alveolar–airway barrier increased exponentially with instilled Ringer vo...