Vaporized perfluorocarbon: taking the "liquid" out of liquid ventilation.

ALTHOUGH only a relatively limited amount of oxygen is dissolved in water under natural conditions, aquatic creatures enjoy great success in extracting sufficient amounts to meet the metabolic demands of life. Mammals (even aquatic mammals) avoid this limitation by using atmospheric oxygen through specialized gas exchange mechanisms in the lung. However, the niammalian lung can also extract sufficient amounts of oxygen from liquids to support life-if it is the right liquid. Many recall from student days the dramatic demonstration that small mammals can be totally immersed for extended periods of time while breathing liquids in which sufficient amounts of respiratory gasses are dissolved.’ Variations of this strategy have been applied with some success in the supportive therapy of acute lung injury (ALI) in both animals and humans. Two techniques have been applied: the lungs can be completely filled with fluid, which is moved to and fro by specialized equipment (total liquid ventilation), or partially filled with liquid, permitting gas ventilation via conventional ventilators (partial liquid ventilation). In this issue of ANESTHESIOLOGY, Rleyl et aZ.2 introduce a new method of delivering liquid to the injured lung that may possess clinical advantages and that raises interesting questions regarding the mechanism of benefit. Indeed, their technique is not liquid ventilation at all, but rather a technique near and dear to anesthesiologists-the inhalation of a “vaporized” agent, in this case a perfluorocarbon.