Decompression illness (DCI) incident during routine decompression of divers from saturation

A member has reported a decompression illness incident during a ‘routine’ and planned decompression of divers in saturation chambers from a storage depth of -160 metres sea water (msw). During the course of the decompression one of the divers complained of pain in his pelvis and knees. The pressure in the saturation chamber at the time of the incident was -93 msw.

Following this report a Diver Medical Technician (DMT) inside the chamber carried out a physical and neurological examination of the affected diver. This found that, aside from the presence of pain in both knees and hips, the condition of the diver appeared essentially normal. On a scale of one to ten the pain experienced by the diver was described as a two. An initial diagnosis of Type 1 (mild) decompression illness was made.

In accordance with standard diving procedures the diver was recompressed to a depth where the pain disappeared (-128 msw). He was then provided with a suitable therapeutic gas treatment mixture through the chamber built-in breathing system (BIBS). On advice from the contracted diving specialist medical adviser the diver (and his two colleagues) were then stabilised and observed at -128 metres for a period of twelve hours. Thereafter normal decompression was recommenced. No re-occurrence of symptoms was experienced by the diver and the team reached surface without further mishap. Following a standard bend watch period all the divers were released to return to their homes.

An investigation team considered if any of the following physiological and environmental factors known to influence DCI had caused or contributed to the incident:

• dehydration;
• age;
• physical fitness/obesity;
• meals;
• exertion;
• temperature;
• previous history of DCI;
• multiple dives;
• nature of dive profiles, including upwards and downwards excursions;
• omitted decompression;
• drugs and alcohol;
• sleep pattern and conditions;
• emotional state/stress.

In addition the investigation team examined the competence and compliance to process of key personnel.

The investigators concluded that the incident could only be attributed to the individual diver’s physiology. However, the following findings were identified:

• the diver’s level of hydration at the time of the incident could not be categorically confirmed;
• Non-approved personal vitamin/protein supplements were taken into saturation;
• No deviations from approved procedure were observed;
• Competence levels were high;
• The diving contractor maintained a very good diving safety culture.

The following recommendations were made:

• Health check, water/fluid intake and urine colour questions should be asked on a daily basis, and the results should be recorded;
• Bag searches should be conducted prior to entering saturation to ensure only controlled items can be taken into saturation;
• Personal vitamin/protein supplements need to be declared prior to entering saturation.

Members may wish to look at the following similar incident:

• Late onset of decompression illness (DCI)