Comparative effects of vaporized perfluorohexane and partial liquid ventilation in oleic acid-induced lung injury.

BACKGROUND It is currently not known whether vaporized perfluorohexane is superior to partial liquid ventilation (PLV) for therapy of acute lung injury. In this study, the authors compared the effects of both therapies in oleic acid-induced lung injury. METHODS Lung injury was induced in 30 anesthetized and mechanically ventilated pigs by means of central venous infusion of oleic acid. Animals were assigned to one of the following groups: (1) control or gas ventilation (GV), (2) 2.5% perfluorohexane vapor, (3) 5% perfluorohexane vapor, (4) 10% perfluorohexane vapor, or (5) PLV with perfluorooctane (30 ml/kg). Two hours after randomization, lungs were recruited and positive end-expiratory pressure was adjusted to obtain minimal elastance. Ventilation was continued during 4 additional hours, when animals were killed for lung histologic examination. RESULTS Gas exchange and elastance were comparable among vaporized perfluorohexane, PLV, and GV before the open lung approach was used and improved in a similar fashion in all groups after positive end-expiratory pressure was adjusted to optimal elastance (P < 0.05). A similar behavior was observed in functional residual capacity (FRC) in animals treated with vaporized perfluorohexane and GV. Lung resistance improved after recruitment (P < 0.05), but values were higher in the 10% perfluorohexane and PLV groups as compared with GV (P < 0.05). Interestingly, positive end-expiratory pressure values required to obtain minimal elastance were lower with 5% perfluorohexane than with PLV and GV (P < 0.05). In addition, diffuse alveolar damage was significantly lower in the 5% and 10% perfluorohexane vapor groups as compared with PLV and GV (P < 0.05). CONCLUSIONS Although the use of 5% vaporized perfluorohexane permitted the authors to reduce pressures needed to stabilize the lungs and was associated with better histologic findings than were PLV and GV, none of these perfluorocarbon therapies improved gas exchange or lung mechanics as compared with GV.