Draper and Whitehead and their co-workers1 have described a phenomenon which they have called ‘diffusion respiration’. In experiments with dogs, they have shown that the blood under certain conditions will be normally oxygenated from the lungs without respiratory movements and without rhythmical changes of pressure in the lungs. They explain this phenomenon as follows. Owing to the affinity of oxygen for hæmoglobin, the amount of oxygen removed from the alveoli during apnea exceeds the amount of carbon dioxide that simultaneously enters from the blood. The pressure within the alveoli is therefore reduced below that of the atmosphere, and a continuous inward movement of the dead-space air and the external atmosphere takes place. Essential conditions, however, for diffusion respiration are a high percentage of oxygen in the lungs and in the dead space, a free airway and an adequate circulation. During the first thirty minutes of diffusion respiration the uptake of oxygen is not reduced. After this time the oxygen consumption and the oxygen content of the blood decrease due, probably, to the Bohr effect produced by retention of carbon dioxide, with respiratory acidosis and low blood pH.
Draper, W. B., and Whitehead, R. W., Curr. Res. Anesthes. Analges., 28, 307 (1949).
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