Liquid breathing can not effectively protect the lung from biophysical forces associated with the gas ventilator. New application modes for PFC have been developed. Partial liquid ventilation (PLV) involves filling the lungs with a fluid. This fluid is perfluorocarbon, also called Liquivent or Perflubron. The liquid has some unique properties. It has a very low surface tension, similar to surfactant, a substance that is produced in the lungs to prevent the alveoli from collapsing and sticking together during exhalation. It also has a high density, oxygen readily diffuses through it, and it may have some anti-inflammatory properties. In PLV, the lungs are
Capillary surface and other energy potentials absent, the energy of the system is where the subscripts formula_40, formula_41, and formula_42 respectively indicate the liquid–gas, solid–gas, and solid–liquid interfaces. Note that inclusion of gravity would require consideration of the volume enclosed by the capillary surface and the solid walls. Typically the surface tension values between the solid–gas and solid–liquid interfaces are not known. This does not pose a problem; since only changes in energy are of primary interest. If the net solid area formula_43 is a constant, and the contact angle is known, it may be shown that (again, for two different fluids