Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 13 Sept 2026Clinical review pending
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Acute intracranial pressure crisis
Falling consciousness, new pupillary asymmetry, posturing or a monitored pressure crisis suggests threatened herniation and can progress before a complete diagnostic picture is available.
Action: Call critical care and neurosurgery immediately, secure airway and circulation, elevate and align the head, obtain urgent imaging when safe, and give protocol-led hyperosmolar rescue without delaying evacuation, drainage or other definitive treatment.
Synopsis
Choose and monitor hypertonic sodium or mannitol as a time-limited bridge for acute cerebral oedema or intracranial hypertension while preserving perfusion and treating the cause.
Hyperosmolar therapy buys time by shifting water from brain tissue into the intravascular space; it does not remove a haematoma, drain obstructive hydrocephalus or reverse the underlying disease.
Choose hypertonic sodium or mannitol from the aetiology, serum sodium, volume status, blood pressure, renal function, access and prior response; no single agent or sodium target is universal across causes and ages.
Treat the patient and trajectory, not an isolated number: reassess pupils, GCS or sedation-adjusted examination, haemodynamics and measured ICP soon after every rescue dose.
Key red flags
A new dilated or poorly reactive pupil with reduced consciousness or hemiparesis is an emergency even before Cushing physiology appears.
Hypotension, hypoxaemia, severe hyponatraemia, hyperthermia, seizure or obstructed venous drainage can worsen secondary injury and must be corrected in parallel.
Repeated osmotic doses without neurological or pressure response suggest treatment failure, an untreated structural cause or loss of an effective osmotic gradient.
Oliguria, rising creatinine, worsening hypovolaemia or a rapidly widening osmolar gap during mannitol therapy signals increased renal and perfusion risk.
Severe hypernatraemia, hyperchloraemia, metabolic acidosis or extravasation during hypertonic-sodium therapy requires immediate reassessment of concentration, access and further dosing.
Clinical pressure crisis
Detect a falling conscious level, pupillary change, new focal weakness, posturing, repeated vomiting or respiratory irregularity. Cushing hypertension and bradycardia are often late and must not be awaited.
Measured ICP rise
Confirm duration, waveform quality, transducer reference and provoking events before treating a monitor value, unless simultaneous clinical herniation demands immediate rescue. Trend and pressure burden matter more than one artifact-prone sample.
Investigation priorities
01
Immediate neurological examinationFirst step
Establish the clinical trajectory and a response baseline before treatment whenever this does not delay rescue.
Management branches
Emergency bridgeSuspected herniation or acute ICP crisis
Clinical herniation signs or a sustained monitored pressure rise accompanied by concerning examination or imaging.
Call neurosurgery and critical care, secure oxygenation and circulation, elevate the head above 30 degrees with neutral neck alignment, control fever and seizure, and stop avoidable noxious stimulation.
Give the institution's protocol-led hypertonic sodium or mannitol rescue selected from sodium, volume, blood pressure, renal function and vascular access while definitive imaging and treatment are arranged.
Key medicines
Mannitol intravenous solutionFor an adult acute ICP crisis, use the weight-based bolus specified by the neurocritical-care protocol; historical BTF severe-TBI guidance gives 0.25–1 g/kg and ENLS v5 gives 0.5–1 g/kg over 5–15 minutes.Avoid uncorrected hypotension or hypovolaemia; monitor urine output, circulating volume, creatinine, measured osmolality and osmolar gap. NCS does not support a single universal osmolar-gap or 320 mOsm/kg stopping threshold.
Hypertonic sodium chlorideConcentration and bolus volume vary by cause, urgency and access; use the local neurocritical-care emergency regimen with pharmacy-ready preparation and route controls rather than extrapolating paediatric weight-based doses.Check baseline and serial sodium, chloride, creatinine, acid–base state and fluid balance; prevent extravasation, choose access appropriate to concentration, and avoid severe hypernatraemia or hyperchloraemia.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 13 Sept 2026; clinical approval remains outstanding.
Neurocritical Care Society cerebral oedema guidelineCook et al., Neurocritical Care 2020, body read 13 September 2026: methodology and population limits; TBI recommendations; disease-specific SAH, ischaemic stroke, ICH and hepatic encephalopathy sections; hyperosmolar safety and infusion considerations. Adult studies were used and paediatric studies were excluded. Recommendations are mostly conditional with low or very-low-quality evidence. Chapter-specific use: hyperosmolar therapy principles.
Emergency Neurological Life Support Intracranial Hypertension and Herniation ProtocolNeurocritical Care Society ENLS version 6.0, last updated September 2024; communication checklist, diagnosis, Tier Zero, Tier One, Tier Two and Tier Three scope read 13 September 2026: crisis recognition, head elevation, SpO2, hyperosmolar treatment, short rescue hyperventilation, CSF drainage and definitive cause control. This multi-aetiology professional consensus protocol requires adaptation to age, aetiology, access and local critical-care protocol and does not make adult severe-TBI thresholds universal. Chapter-specific use: hyperosmolar therapy principles.
Brain Trauma Foundation severe TBI guideline, fourth editionCurrent BTF severe TBI recommendation index, fourth edition 2016 with 2020 decompressive-craniectomy update, read 13 September 2026: hyperosmolar therapy, ICP and CPP monitoring, thresholds, ventilation and CSF drainage. Applies to severe traumatic brain injury; older third-edition mannitol statements are explicitly identified by BTF as not supported by evidence meeting fourth-edition standards. Chapter-specific use: hyperosmolar therapy principles.
Brain Trauma Foundation paediatric severe TBI guideline, third editionCurrent BTF paediatric severe TBI recommendation index, third edition 2019, read 13 September 2026: ICP monitoring; neuroimaging limitations; paediatric ICP and CPP thresholds; hypertonic-saline regimens and safety; CSF drainage and ventilation. Applies only to children with severe traumatic brain injury and contains mainly weak recommendations. Chapter-specific use: hyperosmolar therapy principles.