Ch54 Neuromonitoring in head trauma

Question 1

How do you calculate cerebral perfusion pressure?

Answer 1

CPP = MAP - ICP

Question 2

What metric does autoregulation maintain?

Answer 2

CBF to meet CMRO2 (cerebral metabolic rate for oxygen)

Question 3

What is normal CPP?

Answer 3

>50mmHg (Note: autoregulation occurs between a CPP of 50-150 mmHg)

Question 4

What is the approximate intracranial blood volume? CSF volume?

Answer 4

150ml for both

Question 5

What is the normal ICP in a young child?

Answer 5

3-7mmHg

Question 6

What is the normal ICP in a term infant?

Answer 6

1.5-6mmHg

Question 7

What are the different types of ICP monitors?

Answer 7

1. EVD - (most accurate) 2. Intraparenchymal (different models, some prone to drift) 3. Subdural/subarchnoid/epidural 4. Fontanometry in infants with open AF

Question 8

How do you convert mmHg into cmH2O?

Answer 8

1mmHg = 1.36cmH2O 1cmH2O = 0.735cmH2O

Question 9

What is your target CPP for a head injury patient?

Answer 9

60-70mmHg

Question 10

What is your target blood glucose in trauma?

Answer 10

7-10mmol/l

Question 11

What is targeted temperature management (TTM)?

Answer 11

Aiming for normothermia or mild hypothermia (35.5-37)

Question 12

What did CRASH 3 show?

Answer 12

Safe to give TXA within 8 hours of TBI with intracranial haemorrhage or GCS<12 Improved mortality rates in mild and moderate head injuries. No improvement in severe head injuries

Question 13

What is your target for ICP in head injury patients?

Answer 13

Brain trauma foundation guidelines suggest intervention to keep ICP <22mmHg

Question 14

What are the indications for ICP monitoring in head injury?

Answer 14

BTF guidelines (2016)- All salvageable patients with severe head injury and abnormal CT head Or - all salvageable patients with severe head injury, normal scan and 2 or more of the following - age>40 motor posturing SBP <90 Consensus statement in 2014 suggests that in light of a normal CTH patient should not have ICPM

Question 15

What is the volume of the brain?

Answer 15

1400 ml

Question 16

What is Cushing’s triad?

Answer 16

Hypertension Bradycardia Respiratory irregularity

Question 17

What are Lundberg A waves?

Answer 17

Plateau waves with ICP elevations >50 mmHg for 5-20 minutes

Question 18

What are Lundberg B waves?

Answer 18

Pressure pulses with amplitudes 10-20 mmHg lasting 30 sec - 2 minutes

Question 19

What are Lundberg C waves?

Answer 19

Low amplitude elevations in ICP every 10 seconds.

Question 20

What level of pBt02 should be maintained following head injury?

Answer 20

>25 mmHg improves outcome