Perfluorocarbons

In 1966, Leland Clark and Frank Gollan demonstrated dramatically that a laboratory mouse

Perfluorocarbon Mice
Figure 1.2 Liquid-breathing mouse. The mouse is totally immersed in perfluorocarbon (FC-80, butyltetrahydrofuran) which has been saturated with oxygen by bubbling at room temperature. Such a mouse can survive liquid breathing for many hours (From Clark, 1985).

could survive total immersion in a perfluorocarbon (PFC) solution (Figure 1.2). This material, similar to the commercial Teflon, is almost completely inert, but it is also insoluble in water. Henry Sloviter and Kamimoto prepared a water-soluble emulsion that could be mixed with blood (Sloviter and Kamimoto, 1967), and Robert Geyer and his colleagues were the first to replace completely the blood volume in rats with an emulsion of perfluorotributylamine (Geyer et al., 1968). The animals survived in an atmosphere of 90-100% oxygen, and went on to long-term recovery. However, the oxygen content of the PFCs has a linear dependence on PO2, and a very high oxygen tension is required to transport physiologic amounts of oxygen (Figure 1.3). This and a propensity to be taken up by the reticuloendothelial cells were considered to be severe limitations to the development of clinically useful PFC blood substitutes (Gould et al., 1986).

Until recently, these problems seemed to present insurmountable hurdles to further development. Now, newer emulsions have been developed that allow higher concentrations of dissolved oxygen, and efforts at developing PFC products were renewed in the 1980s. One product, Fluosol-DA, a 20 per cent (by weight) emulsion,

P O2, mmHg

Figure 1.3 Comparison of the oxygen capacity of blood (15 g/dl) and a PFC emulsion (Oxygent™) as a function of PO2. Note that the tetrameric structure of hemoglobin and its cooperativity lead to nearly complete saturation at the arterial oxygen partial pressure of 100 mmHg.

P O2, mmHg

Figure 1.3 Comparison of the oxygen capacity of blood (15 g/dl) and a PFC emulsion (Oxygent™) as a function of PO2. Note that the tetrameric structure of hemoglobin and its cooperativity lead to nearly complete saturation at the arterial oxygen partial pressure of 100 mmHg.

was licensed for use in coronary angioplasty. However, Fluosol-DA did not live up to its early promise because of limited efficacy and a cumbersome packaging system, and it was eventually withdrawn from the market. Newer products that achieve a higher perfluorocarbon content (and hence higher oxygen capacity) have been developed, and are extensively reviewed in this book.

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  • galileo pagnotto
    How perfluorocarbon works in blood substitutes?
    8 years ago

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