Upper respiratory tract and aural flora of saturation divers

SUMMARY The conditions of helium saturation diving promote the proliferation of Gram-negative bacterial species in the external auditory meatus of divers. These changes in flora occurred in the absence of operational diving, that is, no contact with water. The colonising bacteria were auto-genous in origin and cross-colonisation was observed between divers. On return to normal atmos-pheric conditions the aural flora became predominantly Gram-positive again within 48 hours. The slow return to normal pressures by deep-sea divers, necessary to avoid decompression sickness, restricts the period that can be maintained at depth. This problem is overcome by the saturation diving technique whereby the divers are maintained at high pressure in their living quarters and are transported to the sea bed in a detachable diving bell. The com-pression chamber and transfer chamber are anchored to the deck of an oil production platform, and the diving bell is detached and winched down to the required depth. On reaching the depth where they are to work, the divers leave the diving bell through a hatch and, on completion of their work, return to the bell, which is then raised to the platform and locked on to the parent compression chamber complex. Other divers in the compression chamber can then transfer to the bell and work can continue under-water in shifts. The deck compression chamber is fitted out with toilets, showers, beds, and life-support systems in general, allowing divers to recuperate between shifts. Food and other items are passed into, or removed from, the chamber through a small pressure-locked transfer port. A team of six divers in such a system could work, rest, and sleep for up to three months at a time in this artificial environment. The atmosphere within the chambers has a main-tained partial pressure of oxygen of around 0 3 to 0-35 atmospheres. The carbon dioxide level is not allowed to exceed 0-005 atmospheres. The pressure of the atmosphere has to be increased to an equiva-lence of the pressure at which the work has to be performed. The steady partial pressure of oxygen is maintained by adding increasing amounts of helium to the breathing mixture. It is necessary to maintai