Partial liquid ventilation: A multifaceted approach to acute respiratory distress syndrome

In partial liquid ventilation (PLV), a liquid perfluorochemical is instilled into the lungs and ventilation is supported using a conventional respirator. PLV is under development as a treatment for acute respiratory distress syndrome and other forms of acute respiratory failure. The fluid currently in clinical trials is perfluorooctyl bromide, an inert, nonbiodegradable perfluorocarbon which is immiscible with water and very poorly absorbed from the alveolus. It is an avid solvent for oxygen and carbon dioxide and has a remarkably low surface tension. When instilled into the surfactant deficient lung or the lung with surfactant dysfunction, it reduces surface tension at the alveolar lining. The liquid also occupies air spaces, so its presence in the lung recruits atelectatic alveoli. It may also facilitate recruitment by enhancing removal of secretions. There is now evidence that perflubron modulates pulmonary inflammation and that its presence stretches the lung and promotes de novo synthesis of endogenous surfactant. Preclinical evidence suggests that, by several mechanisms, perflubron PLV improves both gas exchange and outcome in animal models of lung disease. Perflubron PLV is now in clinical trials for regulatory approval of human applications.