Infection of the outer ear (otitis externa) is a common problem during saturation diving The most, warm environment of high-pressure heliox facilitates the growth of the gram-negative bacillus Pseudomonas aeruginosa Symptoms of itching, burning, pain and discharge can become intense and result in the diver being unable to work (Farmer, 1982) If, as a result, divers have to leave saturation, this causes inconvenience and loss of earnings to them and disruption of the work schedule they were undertaking
Normal methods of prevention of infections include cleaning of the Interior surfaces and furnishings of the chambers regularly, careful attention to hygiene by divers, including cleaning of personal diving equipment, and avoidance, if possible, of the introduction Into the chamber of divers with existing infections At present, some screening of divers is carried out by culture of ear swabs, but divers are not routinely monitored for asymptomatic carnage of likely pathogenic organisms.
To investigate whether the current techniques of chamber and equipment cleaning were adequate, a study was conducted during a routine commercial diving operation. This study examined the effectiveness of three different disinfectants (Hycolin, Tego and Panacide) in reducing detectable contamination of five areas inside the saturation chambers, and tested for the appearance in two body sites of likely pathogenic bacteria on the divers External ear bacteriological swabs and swabs from predetermined sites within the chambers were taken and cultured every 48 hours Faecal samples were cultured pre-dive, and rectal swabs were taken and cultured once a week throughout the diving operation Facilities were available on the diving-support vessel for culture and screening of culture plates for likely pathogens, and positive cultures were put into transport medium for later laboratory analysis in Aberdeen
During the operation by Wharton Williams (diving contractor) to recover the remaining gold bullion from H M S Edinburgh in the Barents Sea between August 30 and September 24 1986, bacteriological monitoring of the dive was carried out The operation was chosen as suitable for the study because the site of diving was remote from normal laboratory resources in the event that otitis externa became troublesome, and the depth and possible duration of the operation made this quite likely The work was carried out from the diving support vessel Deepwater 11
Three interconnected chambers on the diving-support vessel served as the living quarters for three teams of three divers during the operation (Fig 1) The divers spent 25 days under pressure in the chambers in a heliox atmosphere This was composed of 98 2% helium with 1 8% oxygen, a partial pressure of 0 41 bar oxygen being maintained throughout the operation A pressure of 0 8 bar nitrogen remained in the chamber gas from the initial compression of the chamber system Carbon dioxide was constantly removed from the chamber atmosphere by passage over soda lime.