Metabolic rate and animal size correlated with decompression sickness

Abstract

A number of small animals, rats, guinea pigs, rabbits, and cats were exposed to high ambient pressure for long periods of time and rapidly decompressed. They were found not to suffer from clinical "bends" except when decompressed almost explosively. Usually they did not suffer joint symptoms, delayed shock, or other disabling or permanent sequellae. Nitrogen saturation-desaturation curves based on the small animals' metabolic rate per kilogram weight were derived. A number of small animal dives were analyzed, and the calculated surfacing nitrogen tensions were depicted graphically for six tissues in each animal. It was found that small animals can surface with extremely high nitrogen tensions, particularly in the slower tissues, without serious ill effect. This appeared to be true even in the presence of bubble formation. A clinical description is given of a cat, surfaced from a saturation exposure at 350 ft (106.5 m) with 47 min decompression. It appears that the shorter circulation time of small animals did not by itself explain their immunity to bends.