ICP control

Question 1

REVISE

Clinical signs of Raised ICP

Answer 1

• Headache, vomiting
• Drop in GCS
• Seizures
• Hypertension, Bradycardia
• Unresponsive pupils
• Pappiloedema- UL/BL
• ECG- Twave⬇️, ST segment ⬇️, QT prolongation

Question 2

ICP Control: Tiered System
(J Clin Med, 2022)

Answer 2

A stepwise system for management of ⬆️ ICP where Tt modalities used are prioritised based on their efficacy and relative risks.
Safer Tt- lower tiers
Tt with significant SE- higher tiers.

Question 3

🟢 Tier Zero – Initial ICU Management

Answer 3

i* Admit to ICU
ii* Stabilisation & evaluation:
iii* Airway support: I & V
iv* Sedation & analgesia ( for comfort, facilitate MV)
v* Seizure prophylaxis, monitoring (Art line, CVC, ICP, etc.)
vi* Avoid Hypotension, ⬇️Na, ⬆️thermia
vii* Serial clinical evaluations
viii* Optimise venous return

=>Targets:
* SpO₂ > 94%
* PaCO₂ 35–38 mmHg
* MAP 80–100 mmHg
* CPP 60–70 mmHg
* Temp < 38°C

Question 4

Revise

🟡 Tier One – Escalation for ICP Control

Answer 4

I) Sedation & analgesia- for ICP control

2) PaCO₂: Maintain low-normal (35–38 mmHg)

3) CSF drainage via EVD
- -CPP-60-70mm hg

4) Osmotherapy:
* Mannitol or hypertonic saline (e.g., 3% NaCl)
-Maint. se osmolarity- 320mosm/kg,
Se Na- 155mmol/L

5) Seizure prophylaxis

6) Consider EEG monitoring

Question 5

🟠 Tier Two – If ICP Refractory to Tier One

Answer 5

1. Trial dose of NMB- NDMR better than SUX
2. Mild Hypocapnia- 32-35mm hg
3. Assessment of cerebral autoregulation [⬆️MAP to ⬆️CPP- check if ICP ⬇️es–> if ICP ⬇️es–> autoregulation intact ; titrate MAP to CPP of 60-70mm hg]
   If autoregulation intact, fluids/ vasopressors to increase CPP to 60-70mm hg

Hypocapnia carries risk of cerebral ischemia

Question 6

🔴 Tier Three – Rescue Therapy

Answer 6

1. Mild Hypothermia-35-36
2. Barbiturate Coma
3. Decompressive craniectomy

Question 7

BTF Recommendations

Answer 7

=> Maintain ICP < 22 mmHg

=> Maintain CPP > 60 mmHg

Intracranial Hypertension (ICH) in TBI
-common complication of TBI
- Associated with significant morbidity & mortality

Question 8

Tiered System Approach

Answer 8

• Modalities are prioritised based on:
  
  • Effectiveness
  • Relative risk
  • Lower-tier interventions = lower risk
  • Higher-tier interventions = higher risk

Question 9

Advantages of Tiered System

Answer 9

1. Allows clinicians to avoid unnecessary risk:
   
   • Thorough clinical assessment (before escalation)
   • Use of repeat neuro exam or imaging if needed to confirm pathology and justify escalation

II. May identify:
* Extracranial causes of raised ICP:
* Infection
* Respiratory deterioration
* Seizure
* Other medical disorders

III. Imaging might show:
* Lesions amenable to surgery or evacuation
* Avoiding unnecessary medical escalation

IV. Flexible Decision-Making
* Allows skipping or individualising therapy tiers
* Can omit a tier if next step more beneficial

Question 10

Tier One Therapies – Side Effects

Answer 10

=> Osmotherapy: Both Mannitol & Hypertonic Saline may:
* Cause fluid and electrolyte derangements

=> EVD drainage: Prefer ICP-guided drainage, not scheduled/protocolised
* ⚠️ In significant brain edema, drainage can be:
- Technically difficult
-↑ risk of hemorrhage or misplacement

Question 11

Tier Two Therapy Considerations
I]. Mild Hypocapnia

Answer 11

=>Mild Hypocapnia (PaCO₂: 32–35 mmHg)
I)* Causes cerebral vasoconstriction → ↓ CBF
* Risk of focal cerebral ischemia
* If used, should be:
->Multimodally monitored using:
-> Global & focal cerebral O2 monitoring
> TCD
> SjvO₂
>PbtO₂
* ⚠️ Not widely available in all ICUs

II)* Raised pH →
-↓ blood flow to tissues
- Electrolyte derangements:
(↓ K⁺, ↓ Ca²⁺, ↓ PO₄³⁻)
-↑ risk of seizures

III)* Since CBF is lowest in first 24 hours post-injury: reasonable to avoid hypocapnia during this period

=>* CO2 < 30 mmHg:
* ⚠️ Only to be used temporarily as a bridge (e.g. before surgery)
* Examples:
- Cushing’s reflex
-Impending herniation
* Once stabilized, gradual return to normocapnia is critical–> Prevents rebound intracranial hypertension

Question 12

Neuromuscular Blockade (NMB) in ⬆️ ICP
Indications
Advantages
Disadvantages

Answer 12

=>Advantages:
* May lower ICP by 2–3 mmHg
* ↓ Ventilator asynchrony–> Improved venous return from thoracic vessels- may improve MAP–>CPP

=> Drawbacks:
↑ Risk of:
* Ventilator-associated pneumonia (VAP)
* ICU-acquired neuromuscular weakness (e.g. ICU myopathy)
* Prolonged ICU stay

✅** Indications for NMB:**
*⬆️ ICP not responding to TIER 1therapies
* Severe ARDS or lung contusion
* Abdominal compartment syndrome
* Procedures:
- Bronchoscopy
-Tracheal suctioning
*Hyperthermia due to ↑ CO₂ production (from excess muscle activity)

Question 13

SPAR – Static Pressure Autoregulation Assessment

Answer 13

✅ Method:
* Record baseline MAP, ICP, and CPP
* Stabilise CPP at ≥ 60 mmHg
* Titrate vasopressors to increase MAP by **10mm hg –>Observe ICP response for a maximum of 20mins. **

⬆️MAP–> ⬆️ CPP–> Cerebral vasoconstriction–> ⬇️CBF–> ⬇️Cerebral Bld volume –> ⬇️ ICP

Interpretation:
* ↑ ICP with ↑ MAP → cerebral vasoconstriction fails → poor autoregulation mmHg

If autoregulation is intact- ⬆️ MAP via fluids/Vasopressors

=>Limitations:
* ICP may rise exponentially if SPAR is lost
* MAP elevation may be difficult (esp. trauma, myocardial injury, high baseline)
* SPAR status can change → requires repeat assessment

Question 14

🔴 Tier 3 Therapy –
Therapeutic Hypothermia
Q. Mechanism
Q. Cellular level effects
Q. Risks

Answer 14

💡 Mechanism: Target temp** 35- 36°C** (esp. brain temp)
* ↓ Metabolic demand
* ↓** Brain tissue inflammation

🔬 Cellular-level effects:
* ↓ Excitotoxicity
* ↓ Inflammatory response
* ↓ Cerebral edema (esp. cytotoxic edema)

⚠️ Risks of Hypothermia
*	Pneumonia
*	Cardiovascular complications:
*	Arrhythmias
*	↓ cardiac output
*	Coagulation dysfunction
*	Platelet impairment

Question 15

Hypothermia cont..
Q. Evidence regarding Mild hypothermia
Q. Current recommendations

Answer 15

=> Clinical Trial Outcomes
* No mortality benefit seen in large RCTs
–>Eurotherm- stopped early due to Safety concerns
–> POLAR - No improvement in clinical outcomes

✅ Current Recommendation
*	Mild hypothermia only
*	Target temp: 35–36°C
*	<35°C is not recommended

Compared to other Tier 3 therapies Hypothermia may be more suitable for
* Patients not actively bleeding
* Not surgical candidates eg- medically managed ICP without craniectomy

Question 16

Barbiturates in TBI

Q. Common agents used
Q. Mechanism of action in TBI
Q. Adverse effects

Answer 16

=>Common Agents:
* Thiopentone
* Phenobarbital

=>Mechanism:
*	Induce greater metabolic suppression vs. propofol/midazolam
*	Also possess:
  -	Antiepileptic properties$
  -	Neuroprotective effects (↓ cerebral metabolic demand, ↓ excitotoxicity) $

=>Adverse Effects of Barbiturates
* Hypotension, myocardial depression
* Often requires vasopressors to maintain CPP
* Immunosuppression
* Hepatic and renal dysfunction
* Hypokalemia (esp. during loading phase)
* Hyperkalemia during withdrawal (May become severe enough to need RRT)
* Suppressed pupillary light reflex
* ⚠️ Can mimic brainstem herniation → need for neuro exam via EEG
* Drug accumulation->Prolonged sedation → delayed extubation, prolonged ICU stay

Question 17

Barbiturates in TBI cont..
Q. How will you initiate barbiturate coma in TBI?
Q.** What are the goals of therapy?
Q. What is the End Point?
Q. How will you withdraw Barbiturate therapy?**

Answer 17

=>Initiating Barbiturate Therapy

💉 Dosing
* Test dose of thiopentone (250 mg bolus)
* Assess ICP response
* If ICP ⬇️es with maintainence of CPP→ continue
* Total bolus dose: ~3–5 mg/kg(max-5g)
* Continuous infusion: 3–8 mg/kg/hr
*EEG monitoring recommended

⸻

🎯 End Point
* Aim for burst suppression ≥ 50% on EEG
* Used to assess depth of metabolic suppression

⸻

Goals of Therapy
* Achieve ICP control with minimum effective dose

=>Maintain:
* Euvolemia
* Adequate CPP

⸻

⚠️ Withdrawal Strategy
* Gradual reduction over a few days to prevent rebound ICP increase

Question 18

Decompressive Craniectomy (DC)
Q. Indications
Q. Risks and Complications
Q. Evidence

Answer 18

=> Used for refractory ICP elevation

=>Indications: Ideal Candidates for DC
* Previously fit individuals
* Unilateral pathology
* Good medical and social support
* Early phase of illness
* Non-responders to other treatments

In Limited Resource Settings where advanced monitoring (e.g., ICP, EEG, PbtO₂) is not available:
* Use of basic measures such as:
- Scheduled hyperosmolar therapy
-Continuous infusion of 3% saline

*	Surgical options may be central to management

Question 19

Barbiturates vs Propofol / Midazolam

Answer 19

=>Barbiturates provide:
* More effective suppression of cerebral O₂ consumption.
* Better reduction in metabolic demand
* Neuroprotective advantages

=>Propofol disadvantages (especially in high doses):
*	Cardiovascular depression
*	Pancreatitis, lipemia, PRIS (Propofol Infusion Syndrome)
*	Hepatic dysfunction, Transaminitis     
*	Rhabdomyolysis, renal failure
*	Malignant arrhythmias
*	Cardiovascular collapse
*	Thought to be due to impaired mitochondrial function & lipid metabolism

Question 20

DC cont..

Q. Complications
Q. Evidence

Answer 20

Complications of Decompressive Craniectomy
* Infection
* Bleeding
* Transtentorial herniation
* Hydrocephalus
* Subdural hygroma

⚠️ Risks should be explained clearly to the patient’s family before the procedure.

Question 21

DC cont..
Q. Evidence

Answer 21

🔬 Trial Summaries:

1. DECRA Trial
   -> Early DC (ICP >20 mmHg for >15 mins)
   -> Outcome:
   
   • ↓ ICP but no mortality benefit
   • Worse functional outcomes vs conservative therapy
2. RESCUEicp Trial
   ->DC used after ICP >25 mmHg refractory to medical therapy including hypothermia
   -> Findings:
   
   • ↓ mortality
   • ↑ survivors with severe disability, but
   • Also ↑ chance of favorable outcomes at 12 months

Question 22

Use of Tiered approach

Answer 22

**Use of the tiered approach:
i) When possible, use the lowest tier
ii) Move to the next tier if the ICP remains raised (CPP below 60-70)
iii) It is not necessary to use all the modalities within a tier before moving to the next tier
iv) Tiers can be skipped if this is considered advantageous
**