Raised intracranial pressure (ICP) is a rise in pressure inside the skull, from brain swelling, bleeding, a tumour or blocked cerebrospinal fluid, that can squeeze the brain and lead to herniation and death. The earliest and most sensitive sign is a falling level of consciousness. Cushing’s triad (high blood pressure with a widening pulse pressure, slow pulse and irregular breathing) is a late, life-threatening sign that needs immediate escalation.
Why it matters
The skull is a closed box containing brain, blood and cerebrospinal fluid. When one increases, the others must decrease. Once this compensation runs out, small increases in volume cause big rises in pressure. Normal ICP in adults is about 5 to 15 mmHg. Cerebral perfusion pressure (CPP) is calculated as mean arterial pressure minus ICP; if CPP falls, the brain becomes starved of oxygen.
Common causes
- Head injury, subarachnoid or intracerebral haemorrhage
- Large stroke with swelling
- Brain tumour or abscess
- Meningitis and encephalitis
- Hydrocephalus
- Hypoxic brain injury after cardiac arrest
Early signs of raised ICP
- Falling or fluctuating GCS, restlessness, confusion
- Headache, often worse in the morning or when coughing
- Vomiting, sometimes without nausea
- Subtle pupil changes
- New weakness or speech problems
Late signs
- Cushing’s triad: rising systolic blood pressure with widening pulse pressure, bradycardia and irregular breathing
- A fixed, dilated pupil on one side (third nerve compression), then both
- Abnormal posturing (flexion or extension)
- Deep coma
In infants, a bulging fontanelle, increasing head size and a high-pitched cry are warning signs.
Nursing assessment
- Neurological observations: GCS, pupil size and reaction, limb movement, at the frequency your local policy requires (often every 15 minutes to hourly when unstable)
- A drop in GCS of 2 points or more, or a drop in the motor score, needs urgent medical review
- Vital signs, oxygen saturation, temperature and blood glucose
- Fluid balance and sodium
Nursing care priorities
- Airway and breathing: protect the airway and give oxygen to target saturations. Avoid hypoxia and avoid high CO2, both of which raise ICP.
- Head position: elevate the head of the bed to around 30 degrees (unless contraindicated, e.g. unstable spine), keep the head in the midline, and avoid tight collars or endotracheal tube ties that compress neck veins.
- Blood pressure: maintain the targets set by the medical team to keep cerebral perfusion adequate.
- Prevent rises in ICP: treat pain, fever, seizures, constipation and agitation; avoid unnecessary suctioning and clustered stressful procedures.
- Fluids and sodium: usually isotonic fluids; avoid hypotonic fluids. Monitor sodium closely, as SIADH and diabetes insipidus can occur.
- Medicines as prescribed: osmotic therapy such as mannitol or hypertonic saline, anti-seizure drugs, and dexamethasone for tumour-related swelling (not for head injury).
- Escalate early: use SBAR and call for help immediately with any deterioration.
Frequently asked questions
What is Cushing’s triad?
Hypertension with widening pulse pressure, bradycardia and irregular respirations: a late sign of dangerous raised ICP.
Why is the head of the bed raised to 30 degrees?
It helps venous drainage from the brain, which can lower ICP, while maintaining blood flow.
What is the earliest sign of raised ICP?
A change in level of consciousness, such as restlessness, confusion or a falling GCS.
Related reading: Glasgow Coma Scale explained · Head injury observations · Subarachnoid haemorrhage nursing care
Updated 5 November 2026. Always follow your local neuro-observation and escalation policy.