ADMINISTRATION ROUTES:
IV
ALTERNATIVE NAMES:
Sodium chloride 23.4% concentrated injection, concentrated salt, hypertonic saline
ICU INDICATIONS:
- Prevention or treatment of cerebral herniation in patients with raised intracranial pressure
For the treatment of severe hyponatraemia requiring administration of hypertonic saline, 3% sodium chloride should be used instead.
PRESENTATION AND ADMINISTRATION:
IV:
Clear, colourless solution of sodium chloride (NaCl) in water for injection. The 23.4% solution contains 234 mg (4 mmol) per mL of NaCl. Each 20 mL vial contains 4.68 g of sodium chloride (80 mmol each of Na+ and Cl-).
Administer undiluted, preferably via a central venous line over a few minutes. In an emergency (impending cerebral herniation), can be given more quickly and/or via a peripheral cannula as the risk of tissue necrosis due to extravasation appears to be low, despite its hyperosmolarity.
DOSAGE:
IV:
20 mL bolus repeated to effect
Serum sodium should not exceed 155 mmol/L
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
Administration of sodium chloride 23.4% to patients with renal failure can cause fluid and/or solute overloading resulting in pulmonary or peripheral oedema and electrolyte derangement. Its use in such patients should be balanced with the risk of raised intracranial pressure.
DOSAGE IN PAEDIATRICS:
Do not use 23.4% sodium chloride in children. For treatment of severely elevated intracranial pressure due to head injury, guidelines recommend 3% sodium chloride at an initial dose of 3 ml/kg given over 10 minutes.
CLINICAL PHARMACOLOGY:
Hypertonic saline may reduce intracranial pressure by causing the osmotic shift of fluid from the intracellular space into the intravascular space. There may be other effects on the cerebral microvasculature and blood flow which contribute to a reduction in intracranial pressure. Hypertonic saline is preferred to mannitol for the management of raised intracranial pressure for a number of reasons. It is less likely to cause hypovolaemia (mannitol is an osmotic diuretic), has an easily titratable therapeutic end-point, has less volume, and has a higher osmotic reflection coefficient meaning it is less likely to cross the blood-brain-barrier.
CONTRAINDICATIONS:
- Severe hypernatraemia (serum sodium > 155 mmol/L)
WARNINGS:
Overly rapid increase in serum sodium in patients with hyponatraemia (particularly if chronic) may lead to neurological injury (osmotic demyelination syndrome). Severe hypernatraemia can also cause neurologic effects including delirium, seizures and coma.
PRECAUTIONS:
General:
Monitor fluid status carefully. Hypertonic saline has a diuretic effect. Avoid intravascular volume depletion, which may lead to rebound intracranial hypertension. Conversely, initial plasma expansion by hypertonic saline may cause circulatory overload and pulmonary oedema. Use with caution in patients with congestive cardiac failure or renal impairment.
Laboratory Tests:
Patients with raised intracranial pressure receiving sodium chloride 23.4% must have serum sodium, other electrolytes and acid-base status measured at least 6 hourly. The serum sodium should not exceed 155 mmol/L.
IMPORTANT DRUG INTERACTIONS IN ICU:
The concomitant use of diuretics, corticosteroids and other drugs which affect sodium balance may aggravate fluid and electrolyte disturbances caused by hypertonic saline. Do not administer sodium chloride 23.4% simultaneously with blood products through the same administration set due to the possibility of pseudo-agglutination or haemolysis.
ADVERSE REACTIONS:
General:
Hyperchloraemic metabolic acidosis, hypernatraemia, hypokalaemia, hyperosmolar state, hypersensitivity reactions
Cardiovascular:
Hypotension, circulatory overload / congestive cardiac failure
Respiratory:
Pulmonary oedema
Neurological:
Osmotic demyelination syndrome with rapid correction from hyponatraemia
Haematological:
Possible platelet dysfunction, increased VTE risk (in setting of hypernatraemia)
Skin:
Pain on injection, phlebitis, tissue irritation or damage from extravasation