# Medical Math - Preparing Dextrose Solutions

Megan Brashear, CVT, VTS (ECC), talks through how to perform the calculations necessary to create dextrose solutions.

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## Contributors

Megan Brashear

CVT VTS(ECC)

Enrolled: 07/2011

## Content Assignment

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Thanks for an easy formula to use to make quick calculations in the busy ER!

I teach students to remove an equal amount of fluid from the bag prior to adding a solution like dextrose to be sure that the percent created is accurate. I also show them the alternative, which is how to calculate the amount of dextrose to add should you wish to not remove fluid prior. Any thoughts?

Hi Nikki, yes, when adding a drug to fluid you should remove the equivalent amount to what you are adding. The Constant Rate Infusion Preparation video explains this. Thanks for your comment, good point!

Hi all . Say if you have a 2.5% or 5 % solution and you have a patient that needs more dextrose added to the fluids how would you calculate that.

Michelle, if you need to increase the amount of dextrose to fluids, here's what I would do:
% of new solution - % of current solution, then use that number plugged into the equation. So, if you have a patient with 2.5% dextrose in their fluids (and there are 700ml left) and you are asked to make it 5%, 5-2.5=2.5, so you would go through the equation like this: (700*2.5)/50=35 You would add 35ml of 50% dextrose to your bag (which is already a 2.5% dextrose solution) giving you a 5% dextrose solution.

This helps so much!! Can you guys create a video on preparing mannitol?

The video is great, Thank-you!! The worksheet is confusing though with some of the questions it asks and not indicating which medication it is referring to. For instance Question 3. Calculating Drug Dosages: It gives you the weight of the patient and dosage to give but does not tell you which drug or concentration you are using

Hi Melissa,

Thanks for bringing this to our attention. This worksheet has been reformatted to help clarify any confusion. The questions now refer to the image directly above them on this worksheet. Let me know if you have any questions!

I have a question as the video does not clearly state this but I was wondering if your end total volume is 700ml should you not remove 70ml of IVF before adding the 70ml of dextrose solution?

Hi Jade, yes, when adding a drug to fluid you should remove the equivalent amount to what you are adding. So yes, you would remove 70ml from the IVF before adding the 70ml of dextrose, for an end volume of 700ml. The Constant Rate Infusion Preparation video explains this. Thanks for your comment.