Saline 5%


A) Osmotherapeutic agent for treatment of cerebral oedema

Impending herniation in Traumatic Brain Injury:

  • Unilateral or bilateral pupil dilation
  • GCS < 8 (usually 3)
  • Progressive ↑BP (SBP over 160mmHg) and ↓HR (pulse below 60)

B) Treatment of hyponatraemic seizures

C) Treatment of Exercise Induced Hyponatraemia

  • Severe hyponatremia (Na <120 mmol/L)
  • Significantly symptomatic (e.g. encephalopathy or acute pulmonary oedema)

D) Renoprotective agent (e.g. prevention of radio-contrast toxicity in rhabdomyolysis)

Mechanism of action

  • IV hypertonic saline (HS) osmotically shifts fluid from intracellular to extracellular space
  • It ↓brain water, ↑blood vol and ↑plasma sodium
  • There is no evidence that one formulation of hypertonic saline offers advantages over another.

Advantages hypertonic saline over mannitol

  • Increases circulating volume without the obligatory osmotic diuresis.
  • Demonstrates anti- inflammatory properties with minimal alteration to coagulation.
  • Less rebound intracranial hypertension (Mannitol slow to clear from brain).
  • HS is renoprotective so unlike Mannitol, is safer in olig-anuric renal failure.
  • HS directly ↑ plasma Na+. Measurable changes in blood osmolality easily monitored by plasma Na+ (Mannitol effect requires regular osmolar gap estimations).
  • Mannitol is susceptible to cold and crystallizes in cold conditions. It is also light sensitive and therefore must be stored in the original box.


5% hypertonic saline is kept in a box on top of the drugs press in CUH resusc.


Herniation from TBI

  • 6 ml / kg (to a maximum of 350ml)
  • 5% Hypertonic saline should be delivered by well secured large bore peripheral (> 18 gauge) cannula over 10 min. (HS can cause local vascular irritation)
  • The dose is given once and given regardless of blood pressure.

Hyponatraemic seizures

  • 1.8 mls / kg
  • This is an adjunct to standard seizure management strategies, in confirmed hyponatraemia
  • Aim to increase plasma Na+ by 2-3mmol/L
  • 5% Hypertonic saline should be delivered by well secured large bore peripheral (> 18 gauge) cannula over 10 min

Exercise induced ↓Na+

  • Bolus 60 ml of 5% saline to raise the sodium quickly and prevent cerebral oedema.
  • Up to 2 further boluses of 60 ml 5% saline may be administered at 10 min intervals if there is no clinical improvement.
  • Thereafter, 5% hypertonic saline should be infused at 1 ml/kg/h.
  • This may be increased to 2 ml/kg/h if urine output is inadequate.
  • The infusion rate can be decreased following significant water diuresis.
  • Infusion should be stopped when the patient is asymptomatic with a normal level of consciousness.
  • Serum electrolytes need to be closely monitored (e.g. hourly initially).There are no reports of cerebral pontine myelinoysis resulting from over-vigorous treatment of exercise-associated hyponatremia (an acute process) with hypertonic saline.
  • Aim to correct sodium to a level of 125 mmol/l over 1-2 hours, and to normal level over the following 2-4 hours.
  • 5% Hypertonic saline should be delivered by well secured large bore peripheral (> 18 gauge) cannula over 10 min.

Management accidental infusion 5% saline

  • Stop infusion
  • Contact NPIS (01) 8092566
  • Give Lasix 1mg/kg to promote naturesis
  • Do NOT use IV water or 0.45% saline

Content byDr Jason van der Velde, Ms, Fiona Ahern, Dr √ćomhar O' Sullivan 30/11/2015. Last review Dr JvdV, Ms. FA, Dr ÍOS 15/12/19.