Neuroprotective Strategies

Question 1

General neuroprotective strategies

Answer 1

1. Elevate head up 30 degree
2. No ETT ties around neck
3. Avoid hypoxaemia
4. Normotermia, avoid hyperthermia
   (TTM2 - hypothermia no additional benefits to neuroprotection, increased infection risk)
5. Strict glucose control 8-10mmol/L, avoid hypo/hyperglycaemia
6. Normocarbia to mild respiratory alkalosis, PCO2 30-35
7. Euvolaemia
8. Avoid hypo-osmolar fluids
9. Restrictive transfusion strategy
10. Abate seizures

Question 2

Cerebral perfusion pressure (CPP)

Answer 2

CPP = MAP - ICP
- Aim CPP 60-70

Question 3

Target ICP: ___
Management of raised ICP (4)

Answer 3

Target ICP: < 20 cmH2O

Management of raised ICP:
A. Rule out confounders
B. Non-pharmacological measures
C. Pharmacological measures
D. Refractory measures - surgery

Question 4

A. What are confounders to raised ICP?

Answer 4

1. Malfunctioning ICP monitoring devices
2. Pneumothorax
3. Hypoxia
4. Hypercapnia
5. Pain
6. Hypo/hypertension
7. Hyperpyrexia
8. Seizures
9. Hypo-osmolality

Question 5

B. Non-pharmacological measures to manage raised ICP

Answer 5

1. Head up 15-30 degees
2. Normothermia / cooling measures
3. Ventilator settings - permissive hyperventilation (PCO2 30-35) with good oxygenation - vasoconstriction and reduces intracranial blood volume
4. Check ICP monitoring devices - ensure not malfunction
5. Draining of EVD max 20mL/hr

Question 6

What are possible causes of malfunctioning ICP monitoring devices?

Answer 6

1. Blocked drain
   - CSF output less than reportable limits
   - EVD not oscillating
   - ICP waveform flat
2. High output or bloody drain -> collapse ventricles, subdural haemorrhage
   - CSF output exceeds reportable limits
3. CSF leak
   - Clear fluid on or around entry site
4. Accidental dislodge or removal of EVD
   - Apply pressure to wound site immediately!

Question 7

C. Pharmacological measures to manage raised ICP
D. Surgery

Answer 7

Sedation
1. Fentanyl - analgesia reduces response to suctioning and routine care, improves tube tolerance
2. Propofol - reduces distress
3. Barbiturates

Paralysis
4. Atracurium infusion - improves cerebral venous flow

Hyper-osmolar therapy
5. Hypertonic saline (3% saline) - maintain serum sodium 155-160, do not exceed 160
6. Mannitol

Anti-inflammation
7. Dexamethasone 8mg TDS

Surgery
Decompressive craniectomy - DECRA trial
(Kellie Monroe doctrine)

Question 8

Risk factors for developing seizure
Seizure prophylaxis

Answer 8

Risk factors
1. Glasgow Coma Scale (GCS) Score < 10
2. Cortical contusion
3. Depressed skull fracture
4. Subdural hematoma
5. Epidural hematoma
6. Intracerebral hematoma
7. Penetrating head wound
8. Seizure within 24 h of injury

Seizure prophylaxis
1. Levetiracetam (Keppra)
2. Propofol
3. Additional anti-epileptics as required if seizure develops

Question 9

Liberal (Hb >10) vs restrictive (Hb >7) transfusion strategy in neuroprotection

Answer 9

Alexis et al, NEJM 2024
1. Non-statistically significant difference in neurological outcomes (lib 68.4%, res 73.5%)
2. No difference in mortality and VTE
3. Liberal higher risk for ARDS (lib 3.3% vs res 0.8%)

Limitations
1. Unfavorable baseline anaemia thus higher risk for TBI
2. Restrictive arm has higher proportion of patients with no pupillary reaction