The Trouble with Bubbles

Recent debate amongst some sections of the diving community has concerned the relative benefits of using new ascent and decompression strategies based on calculations of the presence and behaviour of microbubbles. This debate has extended to concern over the relative safety of standard entry level agency decompression/no stop tables. The concern stems from the fact that recent research and opinion regarding the formation of microbubbles on ascent from depth and their role in predisposing towards decompression sickness (DCS), would urge greater caution and, at the very least, slower ascent rates than those recommended in standard diver training. As such, it would seem prudent to review the information that is available in order to have an objective view of the subject of decompression stress and microbubble formation such that informed opinions can be developed prior to recommending any changes in diving practice and/or training principles. Whilst this is certainly relevant to the way our own club views things, obviously the ramifications are broad and need to be viewed in the context of the way the diving community as a whole views and reacts to the current trends. Whilst it is beyond the scope of this article to deal with the theories of decompression and microbubble dynamics in great detail, it is nevertheless necessary to touch on some of the basic principles in order to understand how recent research is changing the way people are thinking at the leading edge of diving. These are the people who are involved in research and in extreme technical diving who need to be able to evolve new and safer techniques in order to push the decompression envelope. It is after all, the empirical testing of these new principles that eventually make our recreational sport diving safer and more enjoyable through the development of better decompression models. Where necessary, the interested reader will be referred to more in depth and informed articles.