Effects on Psychomotor Functions of Different Nitrogen‐Oxygen Gas Mixtures at Increased Ambient Pressures

In order to differentiate and evaluate possible factors responsible for compressed air narcosis, changrs in psychomotor performance (simple and four‐choice visual reaction times and mirror drawing) induced through exposure to different nitrogcn‐oxygrn gas mixtures at raised barometric pressures were studied in 12 subjects. By comparing data from five different experimental conditions evidence was obtained that, at rest, (1) nitrogen pressures up to 3.9 atmospheres absolute have but slight effects on objective performance, and (2) oxygen excess has a potentiating effect on the narcotic action of nitrogen at high pressure. It was concluded that oxygen excess acts indirectly by interfering with elimination of carbon dioxide from the tissues, and that compressed air narcosis is not due to interference with oxidation in the tissues by nitrogen excess.