The limestone caves of the Gambier karst in the south-east of South Australia is where the majority of freshwater cave diving occurs in Australia. The diving in the caves is highly regulated and managed by a single organisation: the Cave Divers Association of Australia (CDAA).
Decompression illness (DCI) includes two pathophysiological syndromes: arterial gas embolism (AGE); and decompression sickness (DCS). Accurate estimates of the rate of DCI in recreational divers are difficult to obtain but have been estimated at 0.96 per cent per 10,000 dives (i.e. 0.01%) for cold-water recreational diving. DCI in technical divers has been studied in the past, but no data has previously been available for cave divers.
Reviewing records of the CDAA and hospital data between 2002 and 2012 the study has estimated the incidence of DCI for cave divers in the Mount Gambier region during this period.
The study reviewed 16 cases of DCI. This included incidents resulting from single deep decompression dives, multiday repetitive dives and a non-decompression dive.
Out of an estimated 57,000 dives during the study period the incidence of DCI in Australia cave divers was estimated to be 0.028%. The study also considered that this could be as high as 0.05% or even higher when dives to depths greater than 90 mfw are involved. Overall the study concluded that the incidence of DCS was lower than expected but consistent with other data analysis of DCI occurrence in cold-water recreational diving.
The original article ‘A 10-year estimate of the incidence of decompression illness in a discrete group of recreational cave divers in Australia’ by Harris et al. and published in Diving and Hyperbaric Medicine Volume 45 No. 3 September 2015 is available here