Perfluorocarbons (PFCs) are hydrocarbons with all of the hydrogen atoms replaced by fluorine.  They have a high solubility for oxygen and carbon dioxide. They can dissolve 3 to 6x10-4 mL/mm Hg/g, which is about 20 to 30 times the amount of oxygen soluble in plasma or water. PFCs are not miscible in plasma, so if injected, will cause embolisms and infarctions. PFCs dissolve oxygen passively, in proportion to oxygen partial pressure.

The first generation clinical PFC was Fluosol-DA-20.  This was a mixture of perfluorodecaline and perfluorotripropylamine emulsified at 20% with Pluronic surfactant.  It was produced by Green Cross Corp. of Japan.  The problems with it were the short half-life of only a few hours, complement activation causing hypertension as well as anaphylactoid reactions, and hepatosplenomegally due to reticulo-endothelial retention.  Researchers found that the perfluorotripropylamine stays in the reticulo-endothelial system for years, the perfluorodecaline is exhaled through the lungs, and the Pluronic surfactant was the cause of complement activation.  Fluosol remains the only blood substitute, of both HBOCs and PFCs, that is FDA approved.  However, it is no longer being manufactured because of low demand.

The second generation clinical PFCs used different PFCs and different emulsifiers.  Low volatility PFCs and egg yolk lipids such as lecithin are now in vogue.  OxygentTM made by Alliance Pharmaceutical Corp. is made of perfluoroctyl (C8F17Br) with lecithin as the surfactant that does not activate the complement system.  OxyfluorTM by HemoGen uses perfluorodichloroctane (C8F16Cl2) with triglyceride and lecithin.

Oxygent is being marketed for use with augmented acute normovolemic hemo-dilution.  This means a portion of the patient’s blood is removed before surgery and stored while a plasma expander is given to maintain blood volume.  Oxygent is administered when the physician would normally give blood during the surgery.

The patient’s stored blood is re-infused towards the end of surgery and during the post-operative period.
There are a couple of real benefits of perfluoro chemicals over HBOCs.  The first is that it can be chemically produced in large amounts without dealing with “messy” biological sources.  Secondly, unlike HBOCs, PFCs are acceptable to those who refuse blood for religious reasons.  Please see “Interview with a Jehovah’s Witness.”