Electrolytes calculation : Na+ and K+ infusions

[Guest Glads Nocon]

Hi there! First, i must say thank you to 99.nicu. I am an RN in NICU for almost 7 years and currently working in Australia. Very well done to all of you. Amazing information and lots of important knowledge. You have added more confidence and made me a better NICU nurse.

Just a question: Do you have a certain formula to calculate the mmol/ kg/ day of a Sodium or Potassium infusions? It seems most of our doctors got stucked with this. And i would like to also share it to most of my colleagues so that they can also question / counter check the Na+ or K+ order.

In our unit, we are currently on a computerized workload, where everything now is done by the computer, therefore, nurses tend to check only the volume of fluids and how many mls added to the 24 hour volume instead of properly checking the mmols/ kg / day the baby is receiving.

Thanks a lot for your help! It will mean a lot!

Kind regards everyone!!!

Edited May 15, 2011 by Glads Nocon

[Stefan Johansson]

Hello and thanks your kind words about 99nicu!

I aim to give sodium 4 mmol/kg/d and potassium 2 mmol/kg/d, and then adjust according to lab parameters.

Sodium is easier to adjust since it's an extracellular ion (one can calculate a Na-deficit by the formula -- xx mmol Na to administer = (goal-Na - measured-Na)*0.6*weight in kg --

Potassium - we aim for a S-K of at least 3 mmol/l. However, since potassium is an intracellular ion, it is difficult to asses the "real" K deficit.

[Guest Glads Nocon]

Thanks a lot for that! I have recommended 99.nicu to some of my colleagues, hope you don't mind!

[Stefan Johansson]

Of course we don't mind. In fact, such viral spread is how more and more people join. So, thanks for telling your friends!

[abeluchin]

" Do you have a certain formula to calculate the mmol/ kg/ day of a Sodium or Potassium infusions?"

I think she is asking how to calculate the moles of Na or K in different solutions that are used to prepare the TPNs.

[khalid]

This is the formula we use in our unit 500 /(ml/kg/day)*mmols/kg/day That is 500 divided by the rate of fluids ml/kg/day multiplied by amount of Na or potassium you prescribe in mmols/kg/day. 500 ml is the total volume of fluid you will be adding electrolytes to..

For instance 500/90*3= 16.6 mmols of sodium. you will be adding 16.6 mmols of sodium to 500ml of say 10%dextrose and if u run this fluid at a rate of 90ml/kg/day you will be giving 3mmol/kg/day of sodium.