Neuro

Question 1

For accurate CPP calcula- tion: where do you zero the transducer for:

• ICP (1)
• MAP (1)

Answer 1

BOTH intracranial pressure (ICP) and MAP transducers should be zeroed

at the level of the external auditory meatus.

BJA Ed

Question 2

useful markers of cerebral ischaemia

Answer 2

• lactate/pyruvate ratio generated via micro- dialysis
• ICP
• tissue oxygenation (PtiO2), which is itself a useful marker for tissue hypoxia.

Question 3

ICP trace is pulsatile, reflecting cardiac and respiratory cycles.

The cardiac component of ICP trace has three peaks, what do each represent

P1?
P2?
P3?

Answer 3

P1 (percussion wave) correlating with arterial pulsation,

P2 (tidal wave) generated by both arterial pulsation and resistance from intracranial pa- renchyma, and
- represents compliance (varies)

P3 (dicrotic wave) - reflects venous p

Question 4

How do you measure CSF pressure directly 4

Answer 4

• lumbar puncture
• lumbar drain
• intra-parenchymal sensor.
• intraventricular (gold standard, hardest to place, probs with infection)

Question 5

Normal values ICP

<1y old
adult

Answer 5

3-4 mm Hg up to 1 yr

10-15 mm Hg in adults
BJA Ed

(another article says 7-13)

Question 6

When is it useful to measure ICP? 4

Answer 6

• traumatic brain injury (TBI),
• hydrocephalus
• stroke
• encephalopathy.

Question 7

Gold standard to measure ICP

Answer 7

intraventricular catheter

Question 8

equation to calculate CPP

Answer 8

CPP1=MAP-ICP

Question 9

What is the goal of maintaining adequate CPP - 2

Answer 9

• maintain cerebral blood flow (CBF)

- maintain tissue oxygenation

Question 10

Methods of monitoring cerebral oxygenation

OXYGENATION - 3

Answer 10

• SjvO2 Jugular venous oxygen saturation
• Near-infrared spectroscopy
• Brain tissue oxygenation (small flexible micro-catheters placed directly into the brain parenchyma in the area of interes)

Question 11

Monitoring CBF

FLOW - 5

Answer 11

• Transcranial Doppler and transcranial colour-coded duplex
• Imaging methods:
• > CT perfusion
• > Xenon-enhanced CT
• > Perfusion-weighted MRI techniques
• > Nuclear medicine methods (PET - Positron emission tomography)

Question 12

Monitoring cerebral metabolism

METABOLISM - 1

Answer 12

Microdialysis

(used in TBI, SAH, post surgery)

measures:
(i) energy-related metabolites (e.g. glucose, lactate, and pyruvate)
(ii) neurotransmitters (e.g. glutamate and aspartate)
(iii) markers of cellular degradation (e.g. glycerol and
potassium)
(iv) exogenous substances (e.g. drugs)

Question 13

Lundberg A wave

pathological or non pathological?

Answer 13

Pathological

suggests raised ICP
low brain compliance

Question 14

Lundberg B wave

pathological or non pathological?

Answer 14

Seen in IPPV

Suggests low brain compliance

Question 15

Lundberg C wave

pathological or non pathological?

Answer 15

Non pathological