Human series of near drowning cases do not show the electrolyte, haematological and cardiac changes seen in animals whose lungs are flooded.
Aspiration causes lung changes and hypoxaemia, which in turn may result in acute respiratory distress syndrome, hypoxic brain damage or cardiac, multisystem or renal disease.
Many patients have survived without brain damage despite total immersion for durations of 15 to 45 minutes. Thus, resuscitation has to be implemented energetically.
Many patients deteriorate or die hours or days after rescue and resuscitation, and therefore observation in hospital is required over this time.
Most patients recover without sequelae, but those with hypoxic encephalopathy may have residual neurological and neuropsychiatric problems.
The pathophysiological process of drowning has been the focus of many attempts to classify and sub-classify, with terms such as ‘drowning’ versus ‘near drowning’, ‘wet drowning’ versus ‘dry drowning’ and ‘secondary drowning’ enjoying periods of popularity. However, a 2010 international consensus determined that these terms contribute little to understanding of the problem and discouraged their use1. A unifying definition of drowning published by the International Liaison Committee on Resuscitation (ILCOR) is as follows: ‘a process resulting in primary respiratory impairment from submersion/immersion in a liquid medium. Implicit in this definition is that a liquid/air interface is present at the entrance of the victim’s airway, preventing the victim from breathing air. The victim may live or die after this process, but whatever the outcome, he or she has been involved in a drowning incident’.