Many definitions and sub-definitions of drowning exist which have resulted in confusion and inability to compare studies on management and outcome. To try and simplify matters, an advisory statement from the International Liaison Committee on Resuscitation (ILCOR) was published in 2003 under the title Recommended Guidelines for Uniform Reporting of Data From Drowning. The “Utstein Style”. In it, drowning was defined as a process rather than an event:

Drowning is 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.

ILCOR also recommended that certain, ill-defined terms should be abandoned, including: wet/dry drowning; active/passive/silent drowning; secondary drowning; near-drowned; drowned.

The sequence of events in drowning that lead to death are summarised in Box 16.1.

When cardiac arrest occurs due to a primary cardiac cause (sudden cardiac death – SCD) the problem is one of failure to circulate blood that, at least initially, is well oxygenated. When cardiac arrest occurs following drowning, the primary cause is hypoxia. In SCD, the priority of treatment is chest compression; in drowning, it is ventilation. Because around 70% of out-of-hospital cardiac arrests in developed countries are due to SCD, standard BLS guidelines are aimed at the majority case with the emphasis on chest compression. One of the important differences to be remembered when managing a case of drowning is that restoration of adequate ventilation is a prime objective.