Hypoxia and Foetal Brain Damage

Question 1

What causes localised capillary dilation in hypoxia?

Answer 1

• Falling oxygen
• Falling pH in tissues
• Rising carbon dioxide
• Rising lactic acid

Question 2

What is unique about preterm babies?

Answer 2

• Capillaries are very fragile in the germinal layer around the ventricles
• Increased dilation of fragile capillaries = periventricular haemorrhage (rupture)

Question 3

How does the nervous system play a part in attempted prevention of hypoxia?

Answer 3

• During hypoxic episodes, sympathetic and parasympathetic pathways attempt to compensate by stabilising HR and BP
• Episodes of bradycardia associated with sudden rises in BP

Question 4

What effect does stress have on the foetus?

Answer 4

• Releases adrenaline
• BP increases
• This may cause rupture of small blood vessels

Question 5

What happens as hypoxia increases?

Answer 5

• Bradycardia and low BP
• Cerebral ischaemia around the ventricles (brain cell death) which may lead to hemiplegia (paralysis of one side of the body)
• Tissue damage may cause blood clots
• Subarachnoid haemorrhage

Question 6

What can resuscitation procedures cause?

Answer 6

• Raised BP

- Vessel rupture