Full blood count (haemorrhage, haemolysis)

Coagulation screen

Electrolytes and creatinine

Glucose (hypo- or hyperglycaemia may be present)

Creatine kinase

Urine stick test for myoglobinuria

Blood alcohol level and urine toxicology screen

ECG (may have changes due to cold (Figure 107.1), myocardial ischaemia, channelopathy (e.g. long QT syndrome), arrhythmia)

Chest X-ray (aspiration, oedema or signs of a foreign body (e.g. segmental atelectasis))

Arterial blood gases and pH

CT head if there are signs of head injury, reduced conscious level or cause of drowning is unclear

Trauma imaging as indicated