Underwater Investigation

Question 1

3 possible mechanisms to drown

Answer 1

• Fresh water
• Water enters lungs à absorbed into circulation (by osmosis) à blood dilution à red blood cells swell & rupture à potassium released à death by hyperkalaemia.
• Salt water
• Water enters lungs à water from blood moves into lungs (by osmosis) à blood thickens à failure of circulation.
• Surfactant
• Water disrupts surfactant à air units (alveoli) collapse à hypoxia.

Question 2

Risk of deep diving

Answer 2

If you ascend/descend too quickly:
• Pulmonary barotrauma – caused by rapid pressure changes
• Can cause pneumothorax, pneumomediastinum, alveolar rupture, air embolism

• Decompression sickness – caused by formation of nitrogen bubbles in blood
• Can cause fatigue, pain, but more severely, stroke-like symptoms.

Question 3

PMI findings:

Internal Signs in drown victim

Answer 3

• Lung changes
• No clear pattern in weights
• Lung over inflation – emphysema aqueosum
• Haemolytic staining of the aorta (fresh water)
• Water in stomach (Wydler’s sign)
• Haemorrhage of middle ear

Not always resent not exclusive to drowing.

Question 4

External signs in PMI finding for Underwater

Answer 4

• Signs of immersion
• ‘washer woman’ hands, mud/debris in mouth, abrasions etc
• Foam around nose
• Disappears with time, disturbed by resuscitation

Question 5

Diving Physiology

Descend = ↑ pressure so your lungs will?

Answer 5

lungs will compress

Question 6

Diving physiology. Ascend = ↓ pressure

your lungs will

Answer 6

de-compress

Question 7

Pulmonary barotrauma – caused by rapid pressure changes, can cause

Answer 7

pneumothorax,
pneumomediastinum,
alveolar rupture,
air embolism

Question 8

Decompression sickness – caused by formation of nitrogen bubbles in blood
• Can cause

Answer 8

fatigue, pain, but more severely, stroke-like symptoms