Experience in Liquid Ventilation

Abstract

Perfluorocarbons are structurally similar to hydrocarbons with the hydrogen replaced by fluorine. The carbon chains vary in length, and an additional moiety often is attached to the molecule which, together, give unique properties to each perfluorocarbon. In general, perfluorocarbons have excellent oxygen and carbon dioxide carrying capacity (50 mL O₂/dL and 160–210 mL CO₂/dL, respectively [1]. They are clear, odorless, inert fluids which are immiscible in aqueous and most other solutions. They are relatively dense (1.7–1.9 gm/mL), have a low surface tension (15–19 dynes/cm), and are relatively volatile with vapor pressures which range from 11 to 85 torr at 37°C. The vapor pressure of the individual perfluorocarbon governs the rapidity with which it evaporates from the lungs after intratracheal administration. As is demonstrated in Fig. 1, perflubron (LiquiVent^®, Alliance Pharmaceutical Corp., San Diego, CA), which is currently the perfluorocarbon most commonly used in clinical studies, is radiopaque, although this is not a characteristic of all of these fluids.