Clinical Dehydration

Initial management

Initial management is oral rehydration

Continue to breastfeed (if applicable)

Otherwise use low osmolality ORS:

  • Calculate deficit (estimated at 5% in this category of child)
  • Calculate maintenance fluid requirements
  • Replace over 4 hours in frequent but small amounts (total replacement rate is usually 10-20ml/kg/hr)
  • Monitor response to oral fluids

Worked example

What is the hourly ORS requirement for a 24 kg child who is clinically dehydrated?


Estimated deficit 5% for this category; fluids will be replaced over 4 hours

Deficit = 5 X 24kg X 10 = 1200 ml

Daily maintenance = (100 ml/kg x 10 kg) + (50 ml/kg x 10 kg) + (20 ml/kg x 4 kg) = 1580 ml in 24 hrs

4 hour maintenance = (1580 ÷ 24) X 4 = 263ml

Hourly requirement for 4 hours of rehydration = (1200 + 263) ÷ 4 = 365 ml/hour

Child refuses to take ORS / continues vomiting

If ORS is refused by the child and there are no ‘red flags’, consider other fluids (i.e. milk, water)

Avoid fruit juices and carbonated drinks

Consider NGT placement if the child is unable to drink and/or vomits persistently

IV rehydration and/or admission may be required if symptoms do not settle

Discharge criteria

If oral fluid is tolerated over first hour, consider child for discharge home

Reassure parents or carers that oral rehydration is usually possible

Provide verbal advice to:

  • Complete the remainder of the 4 hour fluid challenge at home
  • Administer the fluid in small, frequent amounts
  • Breast feeding should be continued throughout rehydration
  • An age-appropriate diet should be started during or after initial rehydration (4-6 hours); dilution of formula is usually unnecessary
  • Seek advice if the child refuses to drink or vomits persistently