Neurointensive Care and Encephalopathies ✅ Flashcards Preview

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Flashcards in Neurointensive Care and Encephalopathies ✅ Deck (89)
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1

What is the purpose of neurointensive care?

Prevent further damage (secondary injury) to the brain and allow best possible recovery from primary insult

2

What is the physiological basis for neurointensive care?

Monro-Kellie doctrine

3

How does the Monro-Kellie doctrine see the head?

As a ‘rigid box’ with a fixed volume

4

What is the fixed volume of the head made up of?

- Brain
- CSF
- Arterial and venous blood

5

What can cause expansion of the brain volume?

- Cerebral oedema
- ‘New matter’ occupying space

6

What ‘new matter’ can occupy space in the brain?

- Expanding haematoma
- Tumour
- Obstructive hydrocephalus

7

How can raised pressure in the head be compensated for?

Reduction in amount of CSF or venous blood

8

How good is the compensation mechanism of reduction in amount of CSF or venous blood?

Limited capacity for compensation, and will still be some increased in ICP towards 20mmHg

9

What is the normal ICP?

5-10mmHg

10

What happens when the capacity of the head to compensate for increased pressure fails?

The system becomes non-compliant and further small increases in volume will produce rapid rises in pressure

11

What is required due to the rapid increase in ICP when compensation mechanisms fail?

Rapid management

12

What management might be used in raised ICP?

- Osmotherapy
- Definitive surgery

13

What is the timeframe for performing definitive therapy to manage raised ICP?

Within 4-6 hours

14

What is the aim of definitive surgery to manage raised ICP?

Remove expanding intracranial mass lesions, e.g. haematoma

15

What happens once ICP exceeds mean arterial pressure (MAP)?

Cerebral perfusion becomes critically impaired, and hypoxic-brain injury may occur

16

What can further increases in ICP past MAP lead to?

- Transtentorial herniation
- Uncus or cerebellar tonsillar herniation

17

What part of the brain is affected in transtentorial herniation?

The innermost part of the temporal lobe

18

What does the uncus or cerebellar tonsillar herniation occur through?

The foramen magnum

19

What does brain herniation (transtentorial, uncus, or cerebellar tonsillar) lead to?

Brainstem compression and ultimately brain death

20

What is tonsillar herniation also known as?

Coning

21

What happens in tonsillar herniation?

The cerebellar tonsils move downward through the foramen magnum, causing compression of the lower brainstem and upper cervical spinal cord

22

What does increased pressure on the brainstem result in?

Dysfunction of the centres responsible for controlling respiratory and cardiac function

23

What investigation is required in all patients with encephalopathy?

Neuroimaging

24

Why do all patients with encephalopathy require neuroimaging?

To make an assessment of ICP

25

What monitoring should be considered in patients with encephalopathy?

ICP monitoring

26

How is ICP monitoring usually done?

Neurosurgical insertion of a fine bore catheter into the substance of the brain through a small burr hole

27

When is ICP monitoring the standard of care?

In traumatic brain injury requiring neurointensive care

28

What is the advantage of ICP monitoring?

Allows accurate assessment of cerebral perfusion pressure (CPP)

29

How is CPP calculated?

MAP - ICP

30

Why is control of CPP important?

To prevent cerebral ischaemia