Intravenous rehydration in children
Intravenous rehydration is usually required for children with severe dehydration, and may be required if the degree of dehydration does not improve with oral or nasogastric rehydration. Check serum electrolytes (especially sodium, potassium and bicarbonate) and glucose concentration at baseline and at least every 24 hours in children receiving intravenous rehydration.
For a child with haemodynamic instability, give 10 to 20 mL/kg sodium chloride 0.9% by rapid intravenous infusion; reassess and repeat if haemodynamic instability persists. Urgently seek advice from a senior clinician about ongoing management and need for transfer to a paediatric critical care service.
For a child who is haemodynamically stable, give intravenous rehydration to replace the fluid deficit—calculated (in mL) using the formula: (premorbid weight [kg] minus current weight [kg]) × 10001. The preferred fluid type is sodium chloride 0.9% with glucose 5%; however, the choice of fluid depends on the clinical features of the child, see the Royal Children’s Hospital Melbourne Intravenous fluids guideline for more information. For a child with mild dehydration, the deficit should be given over the first 24 hours; for a child with moderate or severe dehydration, the deficit should be given over 48 hoursThe Royal Children's Hospital Melbourne (RCH), October 2020.
In addition to replacing the fluid deficit, maintenance fluids should be given at the same time. To determine the maintenance intravenous fluid requirement use the formula in Maintenance intravenous fluid requirements in children] or see the Royal Children’s Hospital Melbourne online calculator. The advice for maintenance fluid calculations is based on requirements for healthy children and should be used as a guide; regular fluid assessment is required, with adjustments if clinically indicated.
A worked example calculation of the total intravenous fluid requirement is given in Example calculation of total intravenous fluid requirement for a child.
Reassess the child’s hydration status within 6 hours of starting intravenous rehydration to determine ongoing fluid therapy planThe Royal Children's Hospital Melbourne (RCH), October 2020. Lack of response to intravenous rehydration may indicate an underlying condition such as infection, septic shock, or a cardiac or metabolic disorder; urgently refer to a paediatric critical care service.
Weight (approximate age) | Daily requirement (mL/24 hours) | Hourly requirement (mL/hour) |
up to 10 kg (up to 1 year) | 100 × weight | 4 × weight |
10 to 20 kg (1 to 5 years) | 1000 + (50 × [weight – 10]) | 40 + (2 × [weight – 10]) |
more than 20 kg (older than 5 years) | 1500 + (20 × [weight – 20]) maximum 2400 | 60 + (1 × [weight – 20]) maximum 100 |
A child with acute gastroenteritis is not tolerating oral rehydration and requires intravenous rehydration. The child has stopped vomiting and has no ongoing significant diarrhoeal losses. Before this presentation, the child weighed 21 kg; the child’s current weight is 19 kg. The child has clinical features of moderate dehydration (9%), so the deficit should be replaced over 48 hours. | |
replacement of fluid deficit (mL/hour) | ([21 – 19] × 1000) ÷ 48 = 41.6 mL/hour |
maintenance intravenous fluid requirement (mL/hour) | 60 + (1 × [21 – 20]) = 61 mL/hour |
total fluid requirement | 41.6 mL/hour + 61 mL/hour = 102.6 mL/hour |
Regularly reassess the child’s degree of dehydration to determine ongoing maintenance fluid requirements and consider whether the route of rehydration can be changed to oral rehydration. Consider discharging the child from hospital when they are tolerating oral intake and have mild or no dehydration.
For more detailed guidance on intravenous rehydration in children, see the Royal Children’s Hospital Melbourne website.