From The Medical Line: Diving After DCS

DAN medical information specaialists and researchers answer your dive medicine questions

Q: I am planning to return to diving after a mild case of cutaneous decompression sickness (DCS), or “skin bends”. If I dive using nitrox, will that be enough to prevent recurrence of DCS?

A: Conservative diving is strongly recommended to avoid a repeat DCS incident. Cutaneous DCS has about a 20 percent chance of having a neurological component. The next event could be similar to this one or be significantly more severe. Diving conservatively, however, involves more than simply switching to nitrox. Consider the following recommendations:

• Dive with nitrox, but set your computer to “air” or “21 percent.” Clearly note the maximum operating depth (MOD) for the mix you’re actually breathing, and never exceed that depth. Use a partial pressure of oxygen (PPO2) setting of 1.4 or lower to avoid oxygen toxicity. If you reset your computer to a nitrox setting, then your potential bottom time will be calculated as longer and defeat the purpose of minimising gas loading. Nitrox is only safer if you shorten bottom times.

• Spend an extended period at less than 9 metres (30 feet), and add long safety stops to allow off-gassing prior to surfacing. Extra stop time in shallow water is an effective way to reduce decompression stress and the likelihood of bubble formation.

• Select the most conservative setting on your computer to limit bottom time.

• Use a slow ascent rate of 6 to 9 metres (20 to 30 feet) per minute.

• Extend your surface interval, especially after long, deep and repetitive dives.