Hypertonic saline is simply a salt solution stronger than normal saline. Common concentrations are 3%, 7.5% and very concentrated 23.4%. Because it pulls water across membranes, it can help clear thick lung secretions when inhaled or raise blood sodium and reduce brain swelling when given intravenously. That power makes it useful — and potentially risky — so understanding when and how it's used matters.
Nebulized hypertonic saline (usually 3%): often used for people with cystic fibrosis, bronchiectasis, and sometimes infants with bronchiolitis. Typical practice is 3% saline in a nebulizer, commonly 4 mL once to several times daily. It can loosen mucus and improve cough clearance. If the patient has reactive airways, clinicians often give a bronchodilator beforehand to lower the chance of bronchospasm.
Intravenous hypertonic saline: used in acute, serious situations. For symptomatic hyponatremia (confusion, seizures), small boluses of 3% saline are commonly given — for example, 100 mL over 10 minutes, repeated if needed, to raise sodium modestly and quickly. For severe intracranial hypertension, concentrated solutions like 23.4% saline are used as small, controlled doses (usually via a central line) to pull water out of the brain and lower pressure. Exact doses and rates depend on the situation and local hospital protocols.
Monitoring is everything. For IV use, check serum sodium often (commonly every 2–4 hours when correcting low sodium). Raising sodium too fast can cause osmotic demyelination, a serious neurologic injury — so clinicians aim for modest, controlled increases, not large jumps. Watch for signs of too much sodium or fluid shifts: extreme thirst, weakness, worsening confusion, or seizures.
Access matters: lower concentrations like 3% are sometimes given through a peripheral IV, but higher concentrations (7.5%, 23.4%) are typically given through a central venous line to avoid vein damage. Be alert for local irritation, pain, or swelling at the IV site.
Nebulized saline can trigger coughing or bronchospasm in some people. If someone suddenly gets worse breathing after inhaled saline, stop and seek medical advice. For home use, follow the breathing treatments exactly as prescribed and keep rescue inhalers handy if recommended.
Final practical rules: never self-prescribe IV hypertonic saline at home, always follow hospital protocols for dosing and monitoring, and ask your care team to explain the target sodium change and monitoring plan. If you’re a caregiver, know which symptoms need immediate help — new seizures, sudden breathing trouble, or rapid mental decline are emergencies.
Hypertonic saline is a simple solution with a big effect. Used properly, it helps clear lungs and stabilise dangerous brain or sodium problems. Used without proper monitoring, it can cause harm. When in doubt, ask a clinician to explain the plan and the safety checks they’ll follow.
