Lessons · Nursing · maintenance fluids by the 4-2-1 rule
Maintenance fluids by the 4-2-1 rule the problem states
The rule, as the problem gives it: 4 mL/kg/h for the first 10 kg of weight, 2 mL/kg/h for the next 10 kg, and 1 mL/kg/h for every kilogram above 20; add the three pieces for the hourly rate.
Hone is a place to practise a career, one idea a day. This is one of its lessons, written out in full and free to read without an account.
What it is for
A paediatric order is written from a weight, and the rate on the pump is the sum of three small multiplications. Done in three lines on paper it is easy; done in one line in your head it is where a kilogram gets counted twice.
How to think about it
Write the weight in kilograms. Split it: the first 10, the next 10, and whatever is left. Multiply each piece by its own number, 4, 2 and 1. Add the three. The answer is mL per hour; times 24 gives the day.
Worked example
Weight 32 kgThe weight in kilograms, converted first if the scale said pounds.
First 10 kg: 10 × 4 = 40 mL/hThe first piece.
Next 10 kg: 10 × 2 = 20 mL/hThe second piece, for the kilograms from 10 to 20.
Above 20 kg: 12 × 1 = 12 mL/hThirty-two less twenty is twelve.
Rate = 40 + 20 + 12 = 72 mL/hThe three pieces added. Times 24 would give the day's volume.
Your turn
A child of 15 kg. Write the kilograms that fall in the second band.
15 - 10 = kg
Solve one, graded on the server
The trap
Multiplying the whole weight by 4. A 30 kg child is not 120 mL/h; the first ten kilograms get 4, the next ten get 2 and the rest get 1, which comes to 70. The rule is three bands, not one rate.