The Pathophysiology of Saturation Diving

The pathophysiology of diving is an important topic to research because of the wide variety and potentially lethal effects caused by high pressure on the body. In this study the pathophysiology is looked at in both the short and the long term to determine the overall effects of diving and in particular saturation diving on the human body. Better understanding of the physiology of these effects will allow the industry to improve the safety record even more, in addition to providing assistance in developing the next generation of techniques for both diving and the treatment of diving related disorders.
Each important area of the body will be examined in depth, looking at the well known short term effects and the lesser known long term effects associated with saturation diving as well as the relevant treatments. It is known that saturation diving has particular effects on the neurological, cardiopulmonary and musculoskeletal systems and the pathophysiology of these is the main focus of this dissertation. However, there are also effects on other body systems that will also be described.

Finally, the treatment protocols followed for saturation diving disorders have a wide range of applications outside the commercial diving industry. The rapidly growing area of recreational diving, in particular, is more frequently utilising the treatments in recent years. Greater understanding of the pathophysiology of diving will lead to new and more effective treatments, resulting in an improvement in the already high treatment success rate observed.
The conclusion reached is that saturation diving has a wide-ranging and in some instances, unknown physiological effects on the body. Further research is still required to fully complete the physiological profile of the conditions that arise from saturation and other forms of diving. A full understanding would allow for the development of more effective and safer diving techniques and treatments. However there is a lack of funding for this research in the current financial climate due the reduction in financial support from the largely oil related, commercial diving industry.

Diving under the water has always fascinated mankind and the invention of diving techniques has allowed man to venture into the underwater world. These inventions started the underwater exploration trend that still continues today and the use of this new technology has created a specialised profession in its own right. As the equipment improved so the depths attained increased along with the dangers because of the poor understanding of the effects of pressure on the body and the gases being used (Nitrogen and Oxygen (air)).

After the Second World War there was an expansion in the diving industry with the advent of mixed gas diving which allowed for greater depths than were achievable whilst breathing air. This led to the advent of saturation diving in the late 1940s. The growth of the industry was small at first until the oil industry boom in the 1960s. As a result there was a rapid increase in the research into the effects of saturation diving on the body as well as the development of new techniques. Alongside the increase in the commercial diving industry there was also a rapid growth observed in recreational diving with organisations established to train and qualify new divers such as the Profession Association of Diving Instructors (PADI) and the British Sub-Aqua Club (BSAC). Understandably the conditions observed in saturation divers are also seen, albeit to a lesser extent, in recreational divers.
Despite all the research completed on the effects of diving and pressure on the human body during the oil industry boom of the last three decades, there are still many unknowns in the understanding of the pathophysiology of saturation diving and diving in general.

Saturation diving is a form of diving that requires the divers to be living under pressure for a long period of time so as to avoid the lengthy decompression required in order to return to atmospheric pressure after each dive. The theory is that after 12 hours or more of being under

pressure the body becomes saturated with gas (equilibrium between partial pressure of gas in the environment and in the body tissues) and can no longer absorb any more gas (Vorosmarti, 1997).
Therefore, the time needed to return to atmospheric pressure during decompression does not proportionately increase the longer you dive after saturation of the body’s tissues has occurred. Economically this is efficient as it allows the divers to work for long periods at a dive site without having to return to atmospheric pressure in between each excursion to the work site. With the explosion of growth seen in the oil industry in the 1960s the demand for commercial divers increased dramatically, along with the need for saturation divers, as the depths of offshore oil exploration increased. The oil industry funded much of the growth and development of the techniques and equipment observed in modern saturation diving along with some assistance from the military, in particular both the British and American Navies.
These techniques and equipment are still in use today, along with the guidelines for decompressing back to atmospheric pressure developed by the Royal Navy and the United States Navy. These guidelines comprise rules where the utmost priority is given to the safety of the diver(s). As a result the accident rate incidence and the overall risks have reduced dramatically over the last three decades.
Saturation diving has a number of effects on individual organs as well as the body as whole. The main areas affected are those that have direct contact with the main causes of injury in divers, the gases they breathe. For example, the cardiovascular and respiratory systems, which are in contact with the unnatural hyperoxic atmosphere the divers breathe whilst under pressure. Here the pressurised gases have a number of effects which can compromise the efficiency of these systems to function. These are particularly noticeable when a diver decompresses too quickly and develops what is called Decompression Sickness (DCS), more commonly known as ‘the bends’. This requires urgent treatment in a recompression chamber (Brubakk et al, 2003).

Most of the effects of saturation diving are reversible in the short term. Long term conditions can develop and these can have permanent debilitating effects if prolonged periods of time are spent living under pressure. In-depth research into the effects of saturation diving was mainly done during the 70s, 80s and early 90s funded by the oil industry to improve the safety records of their operations. Little new research has been done recently because of lack of funding and so the underlying physiology of many of the disorders encountered in the profession are still poorly understood. The effects that saturation diving has on the body are well known though and now there are established theories for the mechanisms of action for them (Brubakk et al, 2003).

There are a number of risks which saturation divers face whilst they carry out their everyday work, related to the factors that they are routinely surrounded by. Danger from both the environment and the equipment are minimised through strict and standardised safety regulations that are enforced and updated regularly. The current controls have been developed over decades of research carried out by the British, French and American Navies, the commercial dive companies, the oil companies and academic institutions (Vorosmarti, 1997). Since their introduction, the number of safety related incidences has dramatically decreased. The profession is therefore a much safer environment to work in than it was at the start of the operations forty plus years ago. This is because the guidelines are based on what is now known and understood about all the potential conditions that can be encountered, whilst still leaving room for the unexpected to occur and are vehemently enforced. Naturally there are still risks present in the undertaking of a saturation dive but the chances of any one of them occurring is very small in the modern diving environment.

The full thesis can be found here: