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For the usage as blood substitutes perfluorocarbons (PFC) have been developed as artificial oxygen carriers. In addition they may have potency for protective use in ischemic tissue. Formulation improvement achieved higher oxygen carrying capacity and better compatibility than the first generation of PFC. Preclinical studies have been performed in animal heart and brain. Former and progressed emulsification for intravascular use have been investigated for infarction and reperfusion injury. This investigations are reviewed and the potencies for the use of PFC in neurology, neurosurgery, diagnostics today and in the future are emphasized.

Perfluorochemical-type blood substitutes are excellent carriers of gases such as O2, CO2, CO, N2. These chemical compounds are insoluble in water and have an extreme chemical and biological inertness. They can be prepared as pyrogen-free sterilisable emulsions. In the last 10 years improvements in emulsion techniques and the results of experimental research work in several laboratories aroused increasing interest in fluorocarbons in the medical and biological field. Beside the treatment of severe loss of blood, numerous further potential uses of these substitutes have been described. Further improvements and studies are needed, especially concerning the storage-phenomenon in the reticulohistiocytic system and also the problems linked with the absence or reduction of the clotting system. The existing literature on this subject seems to justify an optimistic view of fluorocarbons as promising blood substitutes.

In 9 animals 500 ml of blood was replaced with 500 ml of Fluosol DA 20%. An average of 19.2 ml per kg body weight of emulsion, i.e. 3.883 gm per kg body weight of fluorocarbons was given. On the eighth day following exchange transfusion the animals were killed and tissue samples taken from liver and lung for electron microscopy and chemical analysis. Biochemical parameters were measured in central venous blood prior to transfusion and on the 2nd, 3rd, 6th and 8th days. One animal died on the sixth day of study, hence only the results obtained from the remaining 8 animals were analysed. On removing the lungs a marked firmness of consistency and failure to collapse was noted. Electron microscopy revealed numerous phagocytic cells packed with foam-like substance, partly occluding the pulmonary capillaries. On chemical analysis a residue of 23.95 mg fluorocarbon per gm of lung tissue was found. Acid-base analysis of central venous blood showed a compensated respiratory acidosis on the 6th and 8th day. The hepatic reticulo-endothelial system was found to be laden with numerous vacuoles, to such a degree that the sinusoids were all practically fully occluded. Neither cell necrosis nor inflammatory reactions were observed.

About 500 ml of blood of young pigs weighing 20...25 mg were replaced by artificial blood substitute "Fluosol-DA 20%". Eight days after exchange the animals were sacrificed and the liver was fixed for electron microscopic investigation. The morphological studies showed Fluosol-droplets in the cytoplasma of parenchymal cells near the bile canaliculi and in the sinusoidal lining cells. Most Fluosol-droplets were found in the endothelial and Kupffer cells which both seemed to be completely filled. The ballooning of these cells often resulted in a partial occlusion of the sinusoids. The sinusoidal lining cells were saturated by Fluosol droplets to such an extent that they seemed to be unable to phagocytize further.