[pO2, pCO2 and acid-base balance in the human vitreous sample]

In order to clarify the physiological profile in vitreous cavity undergoing vitrectomy, both human vitreous and venous blood samples were obtained to measure pO2, pCO2, acid-base balance and potassium. A new collection system was employed to obtain vitreous samples from 15 eyes under local or general anesthesia. The mean vitreous pO2 was higher than that of venous blood, and was affected by irrigative air more than breathed oxygen. Irrigating air was considered to be one of the best methods to supply enough oxygen concentration to the inner retina during the vitrectomy. Although the vitreous pH showed alkalosis during the air irrigation, it was suggested that to protecting the retina, the vitreous bicarbonate buffer was not enough to compensate for the decrease in the vitreous pH.