Data with subcutaneous gas pockets in rats and theoretical considerations lead to the following conclusions concerning the effects of compression on preformed gas bubbles in the body: 1) Besides mechanically decreasing bubble size, compression causes an additional volume decrease due to readjustment of water vapor, CO2 and O2 volumes in the bubble. 2) The pocket-to-tissue Pn2 difference (in the stabilized condition in which tissue Pn2 equals arterial Pn2) is almost completely dependent on alveolar oxygen, not on compression per se. Compression with air elevates alveolar O2, but the same nitrogen difference could be gained by inhaling oxygen-enriched gas at lower pressures. 3) Compression causes an increased pocket-to-tissue Pn2 difference which hastens N2 absorption, but at the same time decreases surface area and thus tends to slow absorption.
hyperbaric; oxygen; decompression sickness; gas bubbles; high pressure
Submitted on October 26, 1964
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