The way to approach this (especially given the criticality) is to break it
into parts, each in its own cell, then sum the results; that way you can
*see* that the calculation is working.

Define a name for the input cell containing the weight: eg call it 'Weight'

Cell 1: = Min(Weight * 100, 1000)

Cell 2: = IF(Weight 10, Min((Weight - 10) * 50, 500), 0)

Cell 3: = IF(Weight 20, (Weight - 20) * 20, 0)

Dosage = Cell 1 + Cell 2 + Cell 3




"Marc" wrote in message
...
Hi !

My name is Marc and I am a medical resident in Canada. I use MS Excel
2003.
I would need your help in order to find or "set up a calculation strategy"
in
Excel.
When a child has lost lots of fluids (e.g by vomiting), I need to give him
some intravenous fluids. I need to calculate this amount of fluids based
on
the child's weight. In clinic, the formula is :

- For the first 10 kg, it is 100 mL/kg
- For every kg between 10 and 20 kg (included), it is 50 mL/kg
- For every kg above 20 kg, it is 20 mL/kg)

For example,

The child is 9 kg : 9 kg * 100 mL/kg = 900 mL
The child is 16 kg : (10 kg * 100 mL/kg) + (6 kg * 50 mL/kg) =1300 mL
The child is 34 kg : (10 kg * 100 mL/kg) + (10 kg * 50 mL/kg) + (14 kg *
20
mL/kg) = 1780 mL


Would you have any suggestion for a formula to calculate the IV fluids
only
by entering the child's weight in Excel.

Thank you for your help !

Marc A. Allard, MD, MSc
Please, send your suggestions to