Survival Time of Rats Exposed to Different High Oxygen Pressures after Administration of Perfluorochemicals

Abstract

Hyperbaric oxygen administration is considered useful in the treatment of anaerobic infections (Cline and Turnbull, 1985) as well as in tumour radiation therapy (Fischer, Rockwell and Martin, 1986) where very high tissue partial pressures of oxygen are needed. The most commonly used oxygen pressure of 300 kPa (3 ATA) may not be sufficient to reach this goal. There must be sufficient oxygen capacity in the blood to maintain an elevated partial pressure even at the venous end of capillaries when oxygen is consumed. More effective treatment could be accomplished if haemoglobin were to remain in the oxygenated form. The administration of perfluorochemicals (PFC) which increase the oxygen capacity under elevated oxygen partial pressure can help in attaining this goal. However, as judged from previous results obtained by Geyer (1983), hyperbaric oxygen treatment combined with PFC administration can be expected to augment oxygen toxicity considerably. To test this supposition hyperbaric oxygen was applied and survival times were measured in rats as an index of the overall tolerance of the organism at various oxygen pressures. Survival time was found to give a more precise endpoint than the determination of the onset of convulsions. It was the goal of this study to establish the relationship between oxygen tension and lethal duration of exposure in both control and PFC-treated animals.