01Principles and purposeThe professional or clinical skill and the decisions it supports.
Immediate care aims to prevent secondary brain injury while pressure and cause are being defined. Head elevation and neutral alignment improve venous drainage; oxygenation and ventilation limit hypoxic vasodilation; adequate arterial pressure sustains cerebral perfusion; analgesia, sedation and normothermia reduce metabolic and sympathetic surges. These measures operate together. Raising the head while allowing systemic pressure to fall, or ventilating aggressively without cerebral oxygen consideration, can worsen perfusion.
Numerical targets are not universal physiology laws. Brain Trauma Foundation adult recommendations apply to severe TBI: treatment above ICP 22 mmHg, CPP 60 to 70 mmHg, and age-banded systolic pressure minima. Its paediatric guideline separately suggests ICP below 20 mmHg and CPP 40 to 50 mmHg. ENLS supplies a consensus first-hour algorithm across ICP crises, including SpO2 above 94% and head elevation above 30 degrees. Each number must remain attached to its population, clinical setting and monitoring method.
Hyperosmolar and ventilation therapies can provide time but do not remove a clot, drain obstructive hydrocephalus or reverse a growing mass. NCS cerebral-oedema guidance finds low-quality, aetiology-specific evidence and does not support assuming a single agent or sodium target across diagnoses. A pressure-lowering response is not equivalent to improved long-term neurological outcome. Definitive source control, serial examination and tailored monitoring remain central.
Key points
- Start with airway, breathing and circulation; ENLS Version 6.0 advises SpO2 above 94% for an ICP crisis, head elevation above 30 degrees, neutral midline head position, normothermia, analgesia and correction of hyponatraemia.
- Positioning must respect cervical-spine precautions and haemodynamics: preserve alignment, loosen avoidable jugular obstruction and reassess blood pressure and neurological signs after elevation.
- For adults with severe TBI, BTF recommends treating ICP above 22 mmHg and targeting CPP 60 to 70 mmHg; SBP minima are at least 100 mmHg at age 50 to 69 and at least 110 mmHg at age 15 to 49 or over 70.
- For severe paediatric TBI, separate BTF guidance suggests ICP below 20 mmHg and CPP 40 to 50 mmHg, with infants toward the lower and adolescents at or above the upper end.
- Aim for normal ventilation during routine care. In selected active herniation after other measures fail, ENLS permits brief PaCO2 32 to 35 mmHg with cerebral oxygen surveillance; avoid prolonged prophylactic hyperventilation.
- Choose hypertonic saline or mannitol through an age-, cause- and setting-specific protocol, monitor response and toxicity, and progress quickly to CSF diversion or surgery when the lesion requires it.
02Situations and prioritiesThe context, relevant information and actions that matter most.
Inspect head-of-bed angle, neck rotation and flexion, collar fit, endotracheal ties and central lines. Maintain spinal alignment after trauma and correct avoidable jugular compression without compromising immobilisation or airway security.
Look immediately for hypoxaemia, hypotension, hypercapnia, fever, seizures, agitation, pain, coughing and shivering. These can increase blood volume or metabolic demand and are often reversible while definitive care is mobilised.
A falling GCS, new dilated pupil, focal weakness, posturing or abnormal respiration requires an emergency response. Do not postpone rescue measures while waiting for invasive ICP monitoring or the complete Cushing triad.
Before quoting a number, state age, aetiology and severity: monitored adult severe TBI, severe paediatric TBI or a non-traumatic pressure crisis. Then state whether the value is a treatment threshold, minimum or desired range.
Head elevation may reduce arterial pressure; sedation can cause circulatory depression; mannitol can promote diuresis; hypertonic saline alters sodium and chloride. Monitor physiology before and after each change rather than stacking interventions blindly.
Use examination and urgent imaging to identify evacuable haemorrhage, obstructive hydrocephalus, mass lesion or diffuse swelling. Failure to improve after first-tier measures increases urgency for drainage, decompression or lesion evacuation.
03Assessment and interpretationHow to gather information, assess the situation and recognise uncertainty.
Consider the information, its meaning and its limitations before deciding what follows.
- 01
Continuous SpO2, ECG and arterial blood pressure - Why
- Detect hypoxaemia and hypotension promptly and quantify the circulatory effect of positioning, sedation and osmotherapy.
- Interpretation and limitations
- ENLS uses SpO2 above 94% during ICP crisis. Adult severe-TBI BTF SBP minima are age-banded; these should not be substituted for a child’s or non-traumatic patient’s individual resuscitation goals.
- 02
Capnography with arterial blood gas - Why
- Confirm ventilation and guide controlled carbon-dioxide management during mechanical ventilation and temporary rescue hyperventilation.
- Interpretation and limitations
- Maintain normocapnia for routine care. ENLS describes PaCO2 32 to 35 mmHg only for selected acute rescue after other measures fail; prolonged hypocapnia risks cerebral ischaemia and an arterial sample verifies the actual value.
- 03
ICP and CPP monitoring - Why
- Guide therapy continuously in selected severe brain injury and relate MAP to intracranial pressure rather than treating either in isolation.
- Interpretation and limitations
- For adult severe TBI, treat ICP above 22 mmHg and aim CPP 60 to 70 mmHg. For severe paediatric TBI, guidance suggests ICP below 20 mmHg and CPP 40 to 50 mmHg with age dependence.
- 04
Serum electrolytes, osmolality and renal function - Why
- Monitor safety and guide repeated hypertonic saline or mannitol under a specific neurocritical protocol.
- Interpretation and limitations
- Track sodium, chloride, creatinine, fluid balance and serum osmolality or osmolar gap as appropriate. Limits and dosing depend on agent, age and diagnosis; a generic sodium target is not evidence-based across all cerebral-oedema states.
- 05
Urgent CT head and repeat imaging - Why
- Find the lesion that requires evacuation or CSF diversion and assess progression when clinical response is inadequate.
- Interpretation and limitations
- Imaging may show a clot, mass effect, compressed cisterns, hydrocephalus or diffuse swelling. Continue resuscitation during transfer and repeat imaging when new deterioration makes earlier findings obsolete.
04Worked approachesCases with ordered reasoning, an action and a check of the outcome.
01Worked case: first-hour ICP protectionDeteriorating adult before CTAn adult with acute brain injury becomes drowsy and develops anisocoria while definitive imaging and neurosurgical review are being arranged.+
- 1Call emergency, anaesthetic, neurocritical and neurosurgical teams; assess airway, breathing and circulation, apply oxygen to keep saturation above 94%, attach continuous monitoring and prevent hypotension during airway management.
- 2Raise the head of bed above 30 degrees and keep the head midline if circulation and suspected spinal injury permit, correct avoidable neck compression, minimise stimulation and provide adequate analgesia and sedation with repeated pressure checks.
- 3Target routine normocapnia and correct fever, hypoxaemia, hypotension and hyponatraemia; if active herniation persists despite immediate measures, an experienced team may use brief controlled hyperventilation to PaCO2 32 to 35 mmHg while definitive treatment proceeds.
- 4Use cause-appropriate hyperosmolar therapy and monitoring, obtain CT as soon as safe and progress without delay to evacuation, CSF diversion or decompression when indicated.
- 5Verify effect after every step through pupils, motor response, SpO2, arterial pressure, blood gas and ICP or CPP when monitored; deterioration despite improved numbers requires renewed imaging and source control.
02Adult severe-TBI targetsMonitored severe traumatic brain injuryA person aged 15 or older meets the severe-TBI population and is receiving guideline-based invasive monitoring.+
- 1Treat sustained ICP above 22 mmHg in combination with the neurological examination and CT findings; do not treat the number without considering the patient and monitor location.
- 2Target CPP 60 to 70 mmHg and avoid aggressive attempts above 70 because excess fluid and vasopressor exposure can cause harm.
- 3Maintain SBP at least 100 mmHg for ages 50 to 69, and at least 110 mmHg for ages 15 to 49 or over 70, while individualising for bleeding, autoregulation and systemic injury.
- 4Avoid prolonged prophylactic PaCO2 of 25 mmHg or less and avoid routine hyperventilation during the first 24 hours when cerebral blood flow may be critically reduced.
03Paediatric severe-TBI targetsAge-specific monitored careA child with severe traumatic brain injury requires neurocritical ICP-directed treatment.+
- 1Use the paediatric guideline and specialist team rather than adult SBP and CPP targets; age and size affect circulation, drug dosing and monitoring.
- 2Target ICP below 20 mmHg and CPP 40 to 50 mmHg, keeping infants toward the lower end and adolescents at or above the upper end while preventing the 40 mmHg minimum from being breached.
- 3Use paediatric hyperosmolar regimens and toxicity limits when needed, and avoid prophylactic severe hyperventilation below PaCO2 30 mmHg during the initial 48 hours.
05Feedback, follow-up and evidenceReview outcomes, seek feedback and identify what to improve.
- Reassess head angle, midline position, collar and tube security after transfers, scans and nursing care because venous obstruction can recur silently.
- Trend GCS-compatible responses, pupils, motor signs, SpO2, arterial pressure, temperature, end-tidal carbon dioxide and arterial gases through every intervention.
- When ICP is monitored, document waveform quality, zero reference, sustained burden and CPP alongside examination and imaging rather than reacting to artefact.
- During hypertonic therapy, follow sodium, chloride, acid-base state, renal function and fluid balance; during mannitol use, also assess osmolality or osmolar gap and volume depletion.
- After rescue hyperventilation, return toward normal ventilation as soon as the crisis is controlled and verify cerebral oxygen delivery when advanced monitoring is available.
- Record which guideline population justifies each target so that adult severe-TBI numbers do not persist after the diagnosis or age context changes.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Neutral means unobstructed
Head elevation works best when neck flexion, rotation and external pressure do not impede jugular flow. The position must still preserve cervical-spine and airway safety.
CPP is a difference
Because CPP equals MAP minus ICP, reducing systemic pressure can undo the benefit of lowering ICP. Interpret both measurements and the clinical response together.
Threshold is not diagnosis
An ICP treatment threshold in monitored severe TBI does not define every pressure disorder. Herniation can reflect a focal gradient, and chronic IIH uses a different diagnostic framework.
Carbon dioxide has two edges
Hypocapnia rapidly decreases cerebral blood volume but may also reduce blood flow below ischaemic levels. That trade-off confines hyperventilation to brief rescue.
Agent effects differ
Hypertonic saline and mannitol can lower ICP, but the evidence for neurological outcome and preferred strategy varies by aetiology. Patient physiology and protocol monitoring guide selection.
Numbers cannot evacuate lesions
A better ICP value after osmotherapy is temporary success if an expanding clot or obstructed ventricle remains. Continue toward definitive source control.
07Common pitfallsFrequent interpretation and management errors.
- 01
Placing the head high while it remains rotated, flexed or constricted by equipment that blocks venous drainage.
- 02
Pursuing head elevation or sedation despite falling arterial pressure and worsening cerebral perfusion.
- 03
Applying adult severe-TBI ICP, CPP and age-banded SBP values to a child or a non-traumatic pressure disorder.
- 04
Using marked hypocapnia routinely, prolonging rescue hyperventilation or failing to verify PaCO2 with an arterial blood gas.
- 05
Repeating hyperosmolar treatment without assessing neurological response, sodium, chloride, osmolality, renal function and fluid balance.
- 06
Allowing physiological optimisation to delay urgent CT, CSF diversion, haematoma evacuation or decompression.