Oxygen Pneumonitis is Man

Light- and Electron-Microscopic Morphometric Studies

¹ Professor of Pathology, University of Geneva Medical School, Geneva, Switzerland
² Resident in Pathology, University of Geneva Medical School, Geneva
³ Resident in Medicine, University of Geneva Medical School, Geneva
⁴ Associate Professor of Pathology, University of Washington School of Medicine, Seattle, Washington

Morphometric analysis of the lungs of six patients given 60 percent to 100 percent oxygen for 14 hours to 13 days revealed a considerable increase in airblood barrier thickness. This was essentially due to an increase in interstitial tissue; epithelial hyperplasia was less prominent. Other morphometric findings included a decrease in alveolar and capillary surface densities, and in capillary volume. Endothelial volume was greatly reduced, arguing in favor of pronounced endothelial cell injury. These morphometric findings were qualitatively similar to those for monkeys exposed to prolonged hyperoxia. The functional implications of these findings are discussed, and it is postulated, on the basis of morphometric data, that the diffusion capacity of the air-blood barrier should be highly reduced in patients given 60 percent to 100 percent oxygen for periods longer than three days.