Hypotonic Solutions as Intravenous Fluid Therapy in Children Needs Discontinuation!

Hypotonic Solutions as Intravenous Fluid Therapy in Children Needs Discontinuation!

By Dr G.P Mohanta

It may be surprising to notice the use of hypotonic sodium chloride (ex: 0.45%) solution as intravenous maintenance fluid in children. The formulation scientists are always concerned to adjust the tonicity of hypotonic solution to make it isotonic as the former is associated with serious adverse events like haemolysis. 0.9% sodium chloride is recognised as isotonic solution with Sodium concentration at 154 mmol/L. Death and neurologic damage have been reported with hospital acquired hyponatremia in children administered hypotonic maintenance solutions. Intravenous fluid maintenance is necessary for hospitalised children who cannot eat or drink enough to remain hydrated especially after surgery or during stay in ICU.

Traditionally hypotonic sodium chloride intravenous solutions have been used as maintenance therapy. The hypotonic solutions were considered safe in most children due to adoptive mechanisms of the kidney. Kidney removes the excess free water and thus maintains sodium balance. However, increased levels of circulating antidiuretic hormone are more common in hospitalised children than as reported previously, decreasing their ability to excrete excess water and placing them at risk of hyponatraemia.The serious adverse effects, though rare, caused by intravenous fluids are linked to decreased salt level in the body.  Hyponatraemia is said to occur when serum sodium is less than 135 mmol/L representing an excess of water in relation to sodium in extracellular fluids.  Osmotic fluid shifts from the extracellular to intracellular space secondary to hyponatraemia can cause cerebral oedema, which can result in significant irreversible neurological morbidity and death.

More adverse events are reported from fluid administration than for any other individual drug. The incorrect prescription or administration of intravenous fluids are potentially very dangerous. Cochrane review confirms that one hundred and sixty-nine children per 1000 had low sodium levels in the blood when an isotonic fluid was given, compared with 338 children per 1000 when a hypotonic fluid was used. Isotonic sodium chloride solutions are safer bet than hypotonic intravenous fluids in reducing hyponatraemia and promoting patient safety.