Most children who are dehydrated presenting to UK emergency departments can be rehydrated orally. 

• Give 50ml/kg ORS solution over 4hrs, plus ORS solution for maintenance, often and in small amounts (even by syringe or spoon)
• Continue breast feeding
• Consider supplementing with usual fluids (but not fruit juices or carbonated drinks) if a child without red flag symptoms or signs (see http://www.nice.org.uk/CG84) refuses to take sufficient ORS solution.  Don’t give solids.
• Consider giving ORS solution via ng tube if child is unable to take it or continues to vomit (esp. with red flag symptoms/signs)
• Monitor carefully

This is a worked example for a 3 year old child weighing 14kgs who has been assessed as about 5% dehydrated.

Maintenance = 100mls/kg for first 10kgs and 50mls/kg for next 10 kgs = 1000mls + 200mls = 1200mls over 24 hours

Replacement = 5 x 14 x 10 = 700mls over the first 4 hours (extra to maintenance needs)

Therefore the child needs 225mls per hour for the first 4 hours (1200/24 + 700/4), followed by 50mls (1200/24) per hour.

The 225 mls is best given as 18 mls every 5 minutes or 56mls every 15 minutes if vomiting seems to have stopped or if using nasogastric tube.

They should have 5mls/kg = 70mls extra diarolyte (ORS) with each diarrhoeal stool or vomit.

Give parents written information to go home with so they understand that diarrhoea may continue for a few days but this does not matter as long as they are able to get enough fluid in the top end.  The NICE guideline parent information is at http://guidance.nice.org.uk/CG84/PublicInfo/pdf/English.