Neuroprotection and Spinal Precautions

Developing 14 min read

Neuroprotection and Spinal Precautions

By Sammy Reed · 2024

Specialist Topics

Author: Sammy Reed Source: Neuroprotection & Spinal Precautions 2024.pptx (55 slides) Learning Level: Intermediate to Advanced


Learning Objectives


Part 1: Neuroprotection

1.1 What Is Neuroprotection?

Medical management strategies that:

1.2 When Might a Patient Be on Neuroprotection?

Post:

Key facts:

  • TBI is one of the top causes of morbidity and mortality in paediatrics in the UK
  • Head injury is the most common cause of death or disability in 1-40 year olds in the UK
  • 1.4 million ED visits for head injury each year; one-third to one-half are under 15 years old

Part 2: Neuroprotection Principles

2.1 Cerebral Perfusion Pressure (CPP)

CPP is the pressure gradient that drives cerebral blood flow.

CPP = MAP - ICP

  • MAP = Mean Arterial Pressure (pressure pushing blood into the brain)
  • ICP = Intracranial Pressure (pressure pushing blood out of the brain)

Clinical reasoning:

2.2 Mean Arterial Pressure (MAP)

Goal: Drive the MAP high to help CPP.

ConditionEffect on CPPConsequence
HypotensiveReduced CPPBrain ischaemia
HypertensiveIncreased CPPCerebral oedema

Management:

2.3 Intracranial Pressure (ICP)

The cranium is a closed system comprised of:

ComponentProportion
Brain mass80%
Blood10%
CSF10%

These components are tightly packed so will have an element of pressure. If any one component increases in size then ICP will increase. If any component decreases in size then ICP will reduce. CSF protects the brain.

Pathophysiology of raised ICP:

Cerebral oedema (usually 24-72 hours post-injury) causes:

  1. Increased brain mass
  2. CSF displaced into the spinal canal
  3. If displacement is not adequate, blood volume in the cranium decreases secondary to increased ICP
  4. If this is not sufficient, brain mass will be forced out — herniation/coning

ICP Monitoring:

2.4 Signs of Raised ICP in an Intubated and Ventilated Patient

2.5 Target Values

Always check the medical notes for patient-specific targets!

ParameterTarget
ICP< 20 mmHg (via ICP bolt)
CPP — Infants (< 6 years)40 mmHg
CPP — Children (> 6 years)50 mmHg
MAPAs per age

2.6 ICP Reduction Strategies

MDT Strategies

Midline positioning prevents obstruction of arteries and veins in the neck.

Medical Strategies

StrategyMechanism / Notes
3% NaCl fluidRaises sodium, draws water out of neurons via osmosis, reduces oedema and brain mass, reduces ICP
Decompressive craniectomySkull is removed surgically but not immediately replaced; patient needs a helmet for rehabilitation
CraniotomySkull removed to convert cranium into an open system to reduce pressure; bone flap replaced at end of surgery

2.7 Adequate Oxygenation

NOTE: Hyperventilation can cause hypoxia.

2.8 Maintain Normal CO2

CO2 causes vasodilation. The body’s response: if CO2 increases, the body recognises it is working harder, causing vasodilation of blood vessels to meet the body’s demand.

CO2 LevelEffectConsequence
High CO2VasodilationHigher ICP (more blood brought to the area)
Low CO2VasoconstrictionLower ICP BUT reduced blood flow leading to increased risk of hypoxia and ischaemia

A low CO2 will cause vasoconstriction, reducing blood flow and decreasing ICP. However, less blood means less oxygen, which means ischaemia. Also consider potential barotrauma if having to increase ventilation to keep CO2 down. A balance is therefore needed.

Target Values:

ParameterTarget
PaO2> 8 kPa
PaCO24.5 - 5.2 kPa
SpO2Continuous monitoring
EtCO2Continuous monitoring, should match ABG

Always check the medical notes for patient-specific targets!

2.9 Adequate Sedation and Paralysis

Goal: Reduce the body’s metabolic demand to reduce oxygen consumption.

Consider:

Clinical reasoning:

  • Not too high: will cause side effects e.g. withdrawal, delirium
  • Not too low: will increase body’s metabolic demand and patient will fight the ventilator
  • Appropriate sedation reduces oxygen requirement, reduces CO2, and therefore reduces ICP

2.10 Temperature Regulation

TargetAction if Abnormal
36-37 degrees Celsius (optimal)Too high: cool with wet towels and cooling mat
Too low: warm with a bair hugger

2.11 Seizure Activity

2.12 Nursing Care


Part 3: Neuroprotection and Physiotherapy

3.1 Why Is Chest Physio Needed?

3.2 Before Starting Physiotherapy

Checklist before treating a neuroprotection patient:

  1. Liaise with the medical team (Consultant if possible)
  2. Weigh up the risk vs benefit of physiotherapy
  3. Know your parameters and target values
  4. Obtain a good nursing/medical/physio handover
  5. Ask about sedation bolus

3.3 Physiotherapy and ICP

3.4 Physiotherapy and Manual Hyperinflation (MHI)

EffectMechanism
MHI increases intrathoracic volumesReduces venous return from head
Reduced venous returnIncreases ICP
Hyperventilation blows off CO2Causes cerebral vasoconstriction, reducing ICP

You MUST keep the EtCO2 monitor in the circuit whilst bagging!

3.5 Physiotherapy and Positioning

3.6 Additional Physiotherapy Considerations

CRITICAL: Check the CT head report for base of skull fracturesNO nasopharyngeal (NP) suction, NP airway, or NGT if present.


Part 4: Spinal Cord Injuries and Precautions

4.1 Paediatric Spinal Cord Injuries (SCI) — Overview

4.2 Symptoms of Paediatric SCI

4.3 Diagnosis

Imaging Modalities

ModalityNotes
3-view cervical spine X-raysShould not be routinely completed due to radiation effects; cannot always obtain if polytrauma patient
CT scanMore effective in older children where bony fracture injury is more common; usually performed alongside CT head. Role in < 10 years may be less important due to ligamentous disruption without fracture
MRI scanShould be completed if concerns (see below)

Indications for MRI:

  • Unresponsive child with clear X-ray and suspicious MOI
  • Neurological symptoms
  • Unable to clear cervical spine

Cervical Spine Clearance by Age

AgeClearance Method
> 8 years oldCan clear the C-spine with X-ray or CT scan (radiologically)
< 8 years oldMust clear the C-spine radiologically AND clinically

4.4 Clinical Clearance

Gold Standard:

  1. Lift sedation and paralysis
  2. Advise the patient to remain still until the medical team completes assessment (e.g. ROM, pain, GCS, movement patterns)

In reality this rarely happens, so the practical approach is:

Practical approach: Is the patient moving all four limbs appropriately?

ONCE THE C-SPINE IS CLEARED THIS MUST BE DOCUMENTED IN THE CRS NOTES BY THE MEDICAL TEAM (usually PCCU team)

If inappropriate neurology is found (e.g. lesion on CT, no movement, one-sided movements, pain):

4.5 Management of Suspected or Confirmed SCI

Immediate management:

Note: Hard collars can restrict blood flow to the brain and therefore increase ICP, so blocks are preferable when the patient is paralysed.

Ongoing management — MUST be:

4.6 Counterpressures for Stabilisation

Counterpressures counteract the force of manual techniques to ensure the spine remains in alignment.

Counterpressures MUST be applied for:

Vibrations must be BILATERAL and only in SUPINE so equal force is administered through the spine.

Counterpressure Levels by Lesion

Lesion LevelCounterpressure Required
Lesion > T4Shoulder AND cervical spine stabilisation
Lesion T4-T12Shoulder stabilisation

These apply to all manual techniques, coughing, and suctioning. Nursing staff need to be aware to apply these as the patient wakes.

Practical Application

RoleAction
Cervical spine stabilisationEnsure head remains in neutral position
Shoulder stabilisationEnsure shoulders are pushed downwards, backwards, and into the bed

You will need multiple people to ensure an effective treatment! E.g. 1 person for C-spine stabilisation, 1 for shoulder stabilisation, 1 for manual techniques, 1 for bagging/suction.

4.7 Respiratory Innervation and SCI

Key dermatome levels for respiratory function:

LevelInnervation
C3, C4, C5Diaphragm
C1 - T1Accessory muscles
T1 - T11Intercostals
T6 - L1Abdominals

Goal: Detect early deterioration in respiratory function so that management can be guided appropriately.

4.8 Spirometry

FVC (Forced Vital Capacity):

4.9 Peak Cough Flow (PCF)

PCF ValueAction
< 270 L/minAirway clearance techniques (ACT) should be started
< 160 L/minCough augmentation should be started

4.10 Spirometry and PCF — Practical Considerations

4.11 ROM Limitations for Unstable/Uncleared Spine

Lesion LevelROM Limitation
> T4Shoulder flexion to 90 degrees only
T5 - T7Limit hip flexion to 90 degrees
< T8Limit hip flexion to 30 degrees

Note: Frog legs (full external rotation of hips with knee flexion) can be completed for injuries below T8 to maintain range.

4.12 Complications of SCI

ComplicationDescription
Neurogenic shockAssociated with disruption of autonomic pathways within the spinal cord e.g. bradycardias, hypotension. Duration variable but approximately 4 weeks
Spinal shockEarly stages of neurogenic shock; typically characterised by complete loss of muscle tone and absent reflexes
Autonomic dysreflexiaMedical emergency. Sudden onset of excessively high BP caused by an irritant below level of injury (e.g. bowels)
Pressure soresLargest cause of death in SCI patients

References

Cited Guidelines and Resources

Academic References