Pediatrics

Less than 28 days post natal age (PNA)

1 month PNA to 12 months

1 year to 12 years

12 years to 18 years

Very high when they are an infant and neonate, and gradually slow through adolescence

Low as an infant and neonate, then spike and are higher than an adult through childhood and adolescence. Many drugs dosed higher in children but lower in infants.

10%, so within a range of 0.9-1.1 times the original mg amount

Dosing should be dosed based on weight if there is a conflict

Time between the mothers last menstrual cycle and birth of the child (gestational age, GA), plus their post natal age.

100mL/kg/day for the childs first 3.5-10kg, then
50mL/kg/day for every kg over 10-20kg, then
20mL/kg/day for every kg over 20kg

Adults can typically wait longer before starting maintenance fluids, can wait for further labs and testing to be done if needed. Younger children, especially neonates, lose water, vitamins, and other nutrients very quickly and may need a much more rapid maintenance fluid infusion than adults. They will also need to be more rapidly changed to TPN, they shouldn't be on maintenance fluids for more than a day or two.
Children should not be given hypotonic fluids, as these are more likely to result in hyponatremia and complications from that such as death. Normal saline and lactated ringer solution are usually used due to this, in combination with dextrose (D5NS or D5LR). Note that while adding dextrose to these already isotonic fluids makes them slightly hypertonic before dextrose metabolism, children metabolize dextrose so quickly that it is very quickly removed from the solution, returning it to being isotonic. Therefore they are considered isotonic in children.