The Hills' Alternative to Naval Decompression Concepts: a Critical Review

Book excerpt: The approach by Hills is based upon two hypotheses: (1) inert gas transport is limited by diffusion in a single radial model of extra-vascular tissue, and (2) nucleation and phase equilibration between dissolved gas and gas in silent bubbles may preclude supersaturation in excess of 74 mmHg. Actually, two different models, not always clearly distinguished, are presented. One, expounded in theoretical analysis is concerned with gas concentration in a certain average sense over the extra-vascular space. The other, used for his proposed optimum decompression method presumes a restraint on point tensions to 74 mmHg over the diffusion field is necessary to preclude nucleation. (Author)