Oral rehydration in children

Children with clinical features of mild to moderate dehydration (see Assessing clinical features of dehydration in children) can often be adequately rehydrated with oral rehydration.

Water and salt continue to be absorbed by active sodium-glucose–coupled transport in the small intestine, even in patients with severe diarrhoea. Oral rehydration is most effective if fluids containing balanced quantities of sodium and glucose are used, such as proprietary oral rehydration solutions. Soft drinks, sports and energy drinks, cordials and fruit juice are not optimal for use as rehydration fluids in children and may cause further deterioration or dehydration if not properly diluted. However, in children with mild dehydration who cannot tolerate or are refusing an oral rehydration solution, or if an oral rehydration solution is unavailable, it is reasonable to try rehydration using apple juice diluted with water (half strength)Royal Australian College of General Practitioners (RACGP), 2017 or a homemade rehydration solution (see the International Federation of Red Cross and Red Crescent Societies website for instructions).

Several proprietary oral rehydration solutions are available in Australia. These products contain a balanced quantity of sodium and glucose, and have the advantage of also containing other electrolytes such as potassium and chloride. They all have a similar composition, with a sodium concentration of 45 to 60 mmol/L, glucose concentration of 80 to 120 mmol/L and total osmolarity of about 240 mOsm/L.

Oral rehydration solutions should be made up exactly according to instructions, because incorrect preparation can worsen dehydration. Solutions should be refrigerated and replaced every 24 hours. Give frequent small volumes (eg 0.5 mL/kg every 5 minutes) of oral rehydration solution by spoon or syringe. Chilling the solution or making ice blocks may improve palatability. Intermittent vomiting does not preclude the use of oral rehydration.

If the child worsens or does not have a marked response to oral rehydration or has frequent vomiting, change to the nasogastric or intravenous route. If the child is being managed in primary care, arrange transfer to a hospital.