Drowning is defined as the death of an air-breathing animal as a result of submersion in fluid. When patients lose consciousness because of aspiration causing hypoxia, but subsequently recover, the term ‘near drowning’ is used. When symptoms are not severe enough to classify as near drowning, another term, the ‘aspiration syndrome’, is employed.
In divers, and others who submerge after losing consciousness, the pathology of drowning is complicated by the effects of barotrauma in air spaces (e.g. middle ear, sinus, face mask) and decompression artefact.
When I use a word it means just what I choose it to mean – neither more nor less.
Humpty Dumpty, from Lewis Carroll
General reviews indicating the importance of this topic to diving medicine have been presented by diving clinicians such as Sir Stanley Miles, Kenneth Donald, Carl Edmonds, Barbara Tabeling, Christopher Dueker, Tom Neuman and others (see the Further Reading list at the end of this chapter and also Chapters 24 and 25).
Other specialists such as forensic pathologists, epidemiologists, animal researchers and respiratory and emergency clinicians have an equal involvement, but they approach the topic from different aspects. This diversity of interests has had implications not only on terminology, but also on conventional beliefs and prejudices.
The drowning syndromes have been researched extensively for centuries, yet we cannot even agree on the definition.
Drowning, until the nomenclature was changed by the World Congress on Drowning in 2002, meant the death of an air-breathing animal as a result of submersion in a liquid. There were a number of related clinical diagnoses:
Near-drowning referred to a serious clinical syndrome with the loss of consciousness from the submersion, but not resulting in death. It was therefore a lesser condition, but one that could lead to drowning.
Delayed drowning or secondary drowning occurred when the victim appeared to recover from the near drowning incident, but then proceeded to die. This had important management implications.
The aspiration syndrome referred to the lesser effects of aspiration of fluid into the lungs, without death or loss of consciousness.
There was an escalating range in the severity of symptoms and signs among aspiration, near drowning and drowning. They were incorporated together as the drowning syndromes because they needed to be seen as a continuum, for a comprehensive understanding of this disorder.
Post-immersion syndromes referred to the complications that develop after immersion and subsequent rescue. These included pulmonary (infections and inflammations), brain, haematological, renal and multi-system disorders. They also had clinical and management implications.
Other nomenclatures have been proposed over the centuries, based on the type (sea water and fresh water drowning) and amount of fluid inhaled (wet and dry drowning). Modell’s classification of 19711, which was based on survival and on whether aspiration occurred, failed because although death was a clear differentiator, aspiration was not.
These classifications were less clinically valuable and may even be artefactual or misleading. They probably did add to the confusion and deserved the approbation of the World Congress on Drowning.
Thus, by 2002, when the World Congress on Drowning convened, it confronted the problem of a complicated nomenclature, some of which was not very informative. To promote an international statistical conformity for surveillance and comparison of research and epidemiological data, it was decided to use just one all-embracing term – drowning – to cover all such clinical eventualities and not imply an outcome. The World Congress thus succeeded in demographic standardization, but in doing so managed to oversimplify a genuinely complex subject. The Congress then relented with one demarcation qualification – based on outcome, whether the drowning was fatal or non-fatal. In doing so, the Congress managed to re-define a previously well-defined term (‘drowning’) and add an oxymoron (‘non-fatal drowning’). Other subsequent classifications included warm water or cold water drowning. The International Liaison Committee on Resuscitation’s (ILCOR) complex definition in 2010 similarly combined all forms of aspiration, from the most innocuous to the drowning deaths, into the one category (see Chapter 22). This all-embracing approach was not a problem for statisticians, but it resulted in a loss of information and direction for clinicians, most of whom revert to the more useful older definitions.
For clinicians, who need to make management decisions based on the client’s presentation, it is still preferable to distinguish among the following:
- Those who died (drowning).
- Those who lost consciousness and were at risk of dying (near drowning).
- Those who had minor inhalation and transitory symptoms (aspiration).
- Those who had later complications of the aspiration. These include the various forms of organ damage, such as lung, brain and kidney disease.