Endothelial cell toxicity in leg ulcers treated with topical hyperbaric oxygen.

We report the clinical and electron-microscopic features of endothelial cell toxicity in patients treated with hyperbaric oxygen for prolonged periods for leg ulcers. The clinical manifestations include the appearance of depressed white areas within the bed of granulation tissue, which correlated with decreased vascularity under light microscopy. Electron-microscopic findings include endothelial cells with serrated nuclear membranes and degenerate mitochondria in the cytoplasm. These changes occurred in all patients subjected to at least 8 weeks of hyperbaric oxygen, even though an intermittent regimen was adopted. The changes reversed after 1-2 weeks of cessation of hyperbaric oxygen.