Biophysics and Diving Decompression Phenomenology

The biophysics of pressure changes in diving and decompression is extremely complex. Fundamental notions of underlying mechanisms of bubble formation and gas transport are presented. Models are discussed for staging diver ascents focusing on dissolved gas perfusion, bubble formation, and coupled mechanics. Oxygen toxicity is also quantified and detailed. The focus is computational models that have been encoded into underwater computers, tables, and dive planning software. There are some 11 models that have been implemented and safely used by divers, though not all have been tested nor validated.

Models used for safely staging divers by computers, software, or tables need correlation and validation against real diving data. The process of correlating diver profiles and DCS outcomes against predictive models and fundamental parameters is presented. Data from computer downloaded profile records is correlated against several well known models, that is, USN, ZHL16, VPM, and RGBM using maximum likelihood statistical techniques. Results are tabulated, LANL DB discussed, risk functions constructed, and implications for diving and divers detailed.

Model applications are important as predictors of comparative diver staging and protocols. Whether by computer, diveware, or tables, planning is requisite for safe diving. Applications following focus on both shallow and deep mixed gas diving on OC and RB systems. Profiles along with estimated risk are tallied. A bubble model correlated with deep stop diver outcomes is used. Profiles and schedules are listed and compared. Many profiles reside as data entries in the LANL DB. So the applications are both data and comparative dive profiles.