The total daily fluid requirement of a child is calculated from the following formula:
- 100 ml/kg for the first 10 kg,
- then 50 ml/kg for the next 10 kg,
- thereafter 25 ml/kg for each subsequent kg.
For example, an 8-kg infant receives 8 x 100 ml = 800 ml per day, a 15 kg child (10 x 100ml) + (5 x 50ml) = 1250 ml per day.
Give the sick child more than the above amounts if he or she has fever (increase by 10% for every 1 °C of fever).
Monitoring fluid intake
Pay careful attention to maintaining adequate hydration in very sick children, who may have had no oral fluid intake for some time. Fluids should preferably be given orally (by mouth or nasogastric tube).
If fluids have to be given IV, it is important to monitor infusion closely because of the risk for fluid overload, which can lead to heart failure or cerebral oedema.
If it is impossible to monitor the IV fluid infusion closely, the IV route should be used only for the management of severe dehydration, septic shock, delivering IV antibiotics and for children for whom oral fluids are contraindicated (such as those with perforation of the intestine or other surgical abdominal problems). Possible IV maintenance fluids include half-normal saline plus 5% or 10% glucose. Do not give 5% glucose alone as this can lead to hyponatraemia. See Annex 4 for composition of IV fluids.