Nitrogen inhalation in the human.

The neuropathologic findings in the brain of a National Aeronautics and Space Administration (NASA) engineer, who died subsequent to nitrogen inhalation, are reported. Findings which are unusual in other forms of anoxia included relative preservation of neurons in the Sommer sector of the hippocampus and a pattern of damage similar to that of "hypotensive brain stem necrosis" in the cranial nerve nuclei. Some lesions conformed exactly to gray matter structures, whereas others disclosed no respect for anatomic boundaries. Both selective necrosis and relative preservation of neurons were evident in different regions of the brain. Distinct differences between lesions in various areas of the CNS suggest the importance of multiple and complex pathogenetic mechanisms in anoxia caused by exposure to nitrogen.