Exceeding the limits - estimated tissue pressures among Western Australian recreational divers

In Western Australia (WA), approximately 40 divers suffer decompression sickness per year, many after exceeding accepted safe time and depth limits.

Divers on organised recreational scuba dives wore depth/time loggers. Dives ('case' dives) exceeding the Diving Science and Technology gas-content limits (M-values) were matched to control dives made at the same dive site at the same time during which no M-values were exceeded. Potential risk factors for decompression sickness were evaluated using a conditional logistic regression model.

A total of 1,032 organised recreational dives were recorded. Case dives (n = 38) were more likely made by females, deeper than other divers in the water at the same time. They were also made by divers less likely to have previously dived as deep.

One in 27 recreational dives studied exceeded an M-value during the dive, but none on surfacing. We recommend that dive organisers in WA continue to encourage recreational dive groups to watch their displayed remaining no-stop time and to dive within the limits of their training and experience. This study successfully utilised periodic depth/time dive profile analysis using freely available software.