Osmotic agent / ICP reduction Pregnancy: Use only if essential for life-threatening raised ICP.

Hypertonic Saline 3%

Brand names: NaCl 3% Infusion

Adult dose

Dose: 100–150 mL of 3% NaCl IV bolus over 15–20 min for acute ICP elevation

Route: IV (via central line preferred; large peripheral in emergency)

Frequency: As needed (guided by ICP); repeat after 30 min if insufficient response

Max: Guided by serum sodium (target Na 145–155 mmol/L) and osmolality

For TBI/raised ICP: 100–200 mL of 3% NaCl over 15 min. Alternatively 23.4% NaCl (Natrecor) 30 mL via central line. For hyponatraemic seizures: 150 mL 3% over 20 min.

Paediatric dose

Dose: 3 mL/kg

Route: IV

Frequency: As needed — guided by ICP and serum sodium

Max: 150 mL per dose

3 mL/kg 3% NaCl over 15–20 min. Target serum Na 145–155 mmol/L. For symptomatic hyponatraemia: 2 mL/kg over 10–15 min.

Dose adjustments

Renal

Monitor fluid overload; use with caution in oliguria.

Hepatic

Use with caution; sodium/fluid balance may be impaired.

Paediatric weight-based calculator

Patient weight (kg)

3 mL/kg 3% NaCl over 15–20 min. Target serum Na 145–155 mmol/L. For symptomatic hyponatraemia: 2 mL/kg over 10–15 min.

Clinical pearls

Preferred over mannitol if patient is hypovolaemic or hypotensive
No rebound ICP rise unlike mannitol
Monitor serum Na every 2–4 hours; do not exceed Na 155–160 mmol/L
Central line strongly preferred — hypertonic solutions phlebitis risk
23.4% NaCl (30 mL) is potent bolus option for herniation — neurosurgery/critical care use

Contraindications

Hypernatraemia
Hyperosmolality
Cardiac failure (relative — use with extreme caution)

Side effects

Hypernatraemia
Hyperchloraemic acidosis
Fluid overload and pulmonary oedema
Osmotic demyelination syndrome (if sodium corrected too rapidly in chronic hyponatraemia)
Phlebitis (peripheral line)

Interactions

Lithium — increased sodium competes for renal reabsorption, reducing lithium levels

Monitoring

Serum sodium every 2–4 hours
Serum osmolality
Fluid balance
Blood pressure
ICP (if monitored)

Reference: BNFc; BNF; NICE NG234 TBI; BTF Guidelines 4th Edition. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways