Risk factors for running low on gas in recreational divers in Western Australia

The aim of this study was to investigate risk factors associated with running low on gas among certified recreational divers.

Dive and diver information were collected from divers joining organised recreational dives in Western Australia and depth/time loggers were attached to each diver. Case dives ending with < 50 bar in the cylinder were compared with control dives made at the same dive site and time by divers with > or = 50 bar remaining. A conditional logistic regression model identified factors significantly associated with running low on gas.

In total, 1,032 dive profiles were collected. Case dives (n = 183) returning with < 50 bar were compared with 510 control dives ending with > or = 50 bar. Perceived workload was associated with rate of consumption of gas. Factors associated with a dive ending low on gas included: younger age; males; lower number of lifetime dives; a longer period since last dive; deeper maximum depth and breathing at a heavier rate. Eleven per cent of case divers, compared with 1% of control dives, reported surprise at the low remaining level of gas.

Dive organisers are recommended to select dive sites based on the recent experience of the group and to encourage divers to monitor their remaining gas frequently, relative to the depth of the site. Divers are reminded that, if they perceive a strenuous workload, they should pay even closer attention to monitoring their gas reserves. That 89% of low-on-gas dives were reported to be no surprise to the divers making them warrants further investigation.