Help with math!

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Hello. Very confused. I'm in an LPN program. Some of the math I get and some I'm comfused. Can someone do this problem? Teacher wanted us to try even though she did get to this yet.

client is to receive an IV infusion of 500 ml of D5W with 1000 mg of medication. The drop factor is 15 gtt/ml. The dosage of medication ordered is 4 mg/kg/hr. The client weighs 25 kg. Calculate the flow rate in drops per minute.

please help.

Thank you

Specializes in Pharmacy, Mathematics, Physics, and Educator.

Hi Kr,

I just wrote it out and scanned it. I gave up on trying to be neat and doing it on word. Anyway, you start with 4 mg/kg/h. 4 mg/kg is on top and h is on bottom. You multiply both top and bottom by 1/h. Please look at the attached pdf.

-Brad

4 mg kg h.pdf

I want to thank everyone for their help. I printed out some of the stuff you posted and I will probably have to teach myself. I guess I shouldn't say that dimensional analysis is confusing. I never really sat to learn it. Someone asked if we can use any method we want -- yes, the teacher doesn't care which one you use, though she has only showed us formula method because that is how she does it. We do not have an actual dosage calculations class. She is combining showing us how to calculate in our pharmacology class. I do have a dosage calculations book that my boyfriends daughter gave me. I will have to pull that out and I guess teach myself which way works best. I appreciate everyone's efforts on trying to help me with this. Thank you so much!

bjwojcik said:
Hi Kr,

I just wrote it out and scanned it. I gave up on trying to be neat and doing it on word. Anyway, you start with 4 mg/kg/h. 4 mg/kg is on top and h is on bottom. You multiply both top and bottom by 1/h. Please look at the attached pdf.

-Brad

Okay, I looked at your PDF's. I didn't really understand the "4 mg kg h" one. This is what it looked like to me, I wasn't sure if the lines in between were supposed to be division lines or not so, I just wanted to check:

pdf.PNG.8598f7302442ec23a23d3757af30382e.PNG

So, what you're saying is that I just put

1.PNG.4302d34925a2d31372b05136d050c25f.PNG

Instead of:

2.PNG.6f4b92062d08153a8211eb81e09d5019.PNG

But that wouldn't change the dimensional analysis calculation at all then, would it? I would still set it up the same way. Like this:

3.PNG.34603e2ba65dd176125bcc3ed297814a.PNG

Sorry if I'm being a pain!

Specializes in Pharmacy, Mathematics, Physics, and Educator.

Hi Kr,

Yes, that is perfect. You are not being a pain. The only thing that has changed is that you are now setting up the problem correctly and cancelling out the units correctly. I am sure you can see that kg*h is different from kg/h on the bottom.

I would be interested in what you think about the book I wrote and is attached. It was written with pharmacy technicians in mind, but it is still all the same calculations.

-Brad

Dosage Calculations PDF-B.Wojcik.pdf

Hi Kr,

Yes, that is perfect. You are not being a pain. The only thing that has changed is that you are now setting up the problem correctly and cancelling out the units correctly. I am sure you can see that kg*h is different from kg/h on the bottom.

I would be interested in what you think about the book I wrote and is attached. It was written with pharmacy technicians in mind, but it is still all the same calculations.

-Brad

Great! Thanks! I always knew that it was kg*h, like if I did it separately when calculating, I just didn't realize it mattered when I was putting it in the calculations together! Thanks! I will definitely check out the book and let you know!!

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