Decompression sickness from saturation diving: a case control study of some diving exposure characteristics

Area of Science:

• Diving Medicine
• Occupational Health
• Hyperbaric Physiology

Background:

• A comprehensive database of offshore diving activities from 1983-1990 was compiled for Stolt-Nielsen Seaway (SNS).
• Preliminary analysis suggested decompression sickness (DCS) might result from accumulated pathophysiologic effects during dives.
• This led to the development of the Highest Accumulated Decompression Score (HADES) theory.

Purpose of the Study:

• To investigate the incidence of DCS among SNS divers.
• To identify specific saturation diving characteristics associated with DCS.
• To test the predictive capability of the HADES theory.

Main Methods:

• A nested case-control study design was employed.
• Twenty-one case dives (DCS occurred) were compared with 41 randomly selected control dives.
• Saturation dive characteristics, including pressure changes and storage depth variations, were analyzed.

Main Results:

• The relative pressure change between maximum and minimum storage depths was significantly greater in case dives compared to controls.
• A 1% increase in relative pressure change correlated with a 5% increase in DCS probability.
• Dives with multiple storage depths and greater/more frequent depth changes were more common among cases.

Conclusions:

• Significant pressure fluctuations during saturation dives are linked to an increased risk of DCS.
• The HADES theory provides a framework for understanding and potentially predicting DCS based on accumulated decompression stress.
• Minimizing pressure variations during saturation dives may be crucial for preventing DCS in offshore environments.