Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid. Drowning outcomes are classified as death, morbidity and no morbidity – the latter two now referred to as “non-fatal drownings”. [ARC 2016]
Signs and symptoms:
The most important consequence of drowning is interruption of oxygen supply to the brain.
Some amount of water is aspirated into the airways causing coughing and sometimes laryngeal spasm.
Respiratory impairment causes brain hypoxia, leading to unconsciousness and cessation of breathing efforts.
The heart rate initially increases with exercise and panic. With hypoxia, the heart rate and blood pressure begin to fall, progressing finally to a cardiac arrest, requiring CPR.
Treatment: Remove patient from the water as soon as possible but do not endanger your own safety.
Full DRSABCD assessment, manage ABC as necessary. Avoid delays or interruptions to CPR (if required)^. If practical, locate the closest AED and bring it to the patient
Assess the patient on the back with the head and the body at the same level
Administer oxygen if available and authorised to do so
Remove wet clothing, dry and hypo-wrap patient.
Patients who appear to have been successfully rescued and resuscitated require close monitoring to detect a relapse into cardiopulmonary arrest.
^ The Australian Resuscitation Council  states: Compression-only CPR is not the recommended resuscitation method.
Evacuation: Consider: RAPID; Rapid Evac: Anyone suspected of a drowning episode (non-fatal drowning).