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.
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.
- 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