Steady state compositions of tissue gas pockets in rats in hyperoxic environments

This is a study of composition and rate of N₂ exchange of artificially formed gas pockets in unanesthetized rats exposed to O₂ enriched environments up to 6 Ata. Despite limitations of the technique, the following conclusions were reached: The maximal rise of tissue PCO₂, attributable to the hyperoxia was 11 mm Hg except in rats severely afflicted by oxygen toxicity. High pocket PO₂ in hyperoxic environments is partly artifact, perhaps partly a reflection of better arterial oxygenation, and probably not due to increased blood flow to the tissue. Tissue PCO₂ was above 100 mm Hg in rats that had convulsed due to O₂ toxicity, and was about 6 mm Hg below normal the day following exposure to toxic levels of O₂.