Below are a few simple rules aimed at giving safe answers that are suitable for an exam, the reality of the matter in the ED is that if you are in doubt there are all sorts of useful resources that can guide you e.g. your boss or the paediatric reg/ PICU. There are even apps to help with the calculations.
For the purposes of the below assume I am referring to 0.9% sodium chloride unless stated otherwise.
Step 1:
Know the child's weight, you cannot proceed without this, but you may have to work it out:
- 0-12 months: weight = (0.5 x age in months) + 4
- 1-5 yrs: weight = (2x age in years) + 8
- 6-12 years: weight = (3x age in years) + 7
Step 2:
Bolus for the shocked child: know the cause of shock
- Sepsis: 20ml per Kg
- Hypovolaemia/ trauma: 10ml per kg
- DKA: 10 ml per kg - do not exceed 30ml per kg in total -
- and if you are managing a child with DKA and needing fluid boluses you should probably not be managing them on your own!!!
Step 3:
Maintenance fluids: "4-2-1 rule"
- 4mls per Kg for the first 10 kgs
- 2mls per Kg for 10-20 kgs
- 1mls per Kg for 20+ Kg
Worked example:
22kg child =
4mls x 10 +
2mls x 10+
1ml x 2 = 22 ml/ hr
Don't forget that maintenance will need to consider potassium and dextrose to be included in regime.
Step 4:
Special circumstances:
- DKA: can't stress this one enough - cautious fluid is the order of the day and rehydration may be undertaken over a 48 hr period!!!
- Burns: remember Parkland 4x %BSA X Weight - give half over first eight hours from injury and then second half over next sixteen hours.
- Dehydration: similar to burns you can calculate the deficit by working out the %dehydration x weight.
- Hypoglycaemia - weight x 2mls - here the fluid is 10% dextrose
Questions:
1) What is your estimated weight for a seven year old boy?
2) What would be a suitable maintenance fluid regime for this child?
3) He has sustained 6% partial thickness burns, what are his fluid requirements over the first 24 hours.
4) How much dextrose would a hypoglycaemic 6 month old require?
