Rapid ascent and buoyancy problems among Western Australian certified recreational divers

We investigated risk factors associated with ascending rapidly and/or losing buoyancy control among recreational divers.

Dive and diver information were collected and depth/time loggers attached to recreational divers. Case dives recording an ascent > 18 m per min were compared with control dives made at the same dive site and time by divers recording ascents ≤ 18 m per min. In a second analysis, case dives with reported buoyancy problems were compared with control dives during which no problems were reported. Conditional logistic regression identified factors significantly associated with ascending faster than 18 m per min or reporting a buoyancy problem.

In total, 1,032 dive profiles were collected. Case dives (n = 71) recording an ascent > 18 m per min were compared with 282 control dives. The main risk factor for making a rapid ascent was a loss of buoyancy control. Case dives were also shorter. Dives resulting in reported buoyancy problems (n = 68 cases) were compared with 320 control dives. The three main risk factors for buoyancy problems were an inability to describe how to check for neutral buoyancy, reportedly not being in control during the final ascent and maximum ascent rates that were a mean of 20% faster than during control dives.

Further research is necessary to identify if ascending rapidly is the result of a loss of buoyancy control, a lack of ascent rate reference or a failure to appreciate the potential consequences of ascending rapidly. The inability of many divers to describe how to check for neutral buoyancy also deserves attention.