IV Calculation Help!

[SweetSouthernLove, ASN, BSN]

Hey All!

I have been a little confused about some of my IV calculation questions. I have been doing most of them right but three I am having trouble with, so any help would be amazing! Thank you in advance!

1. The pharmacy adds 10,000 units (of any med) to 500 ml (of any IV solution). If the IV is run at 10ml/hour, how many units per hour will infuse?

2. The pharmacy adds 1,000 mg (of any med) to 500 ml (of any IV solution). If the IV is to run at 40ml/hour, how many mg/hr will infuse? (For this I got 20mg/hr using ratio proportion)

3. The pharmacy adds 5,000 mcg (of any med) to 1,000 ml (of any IV solution). If the IV is to run at 50ml/hr, how many mcg/hr will infuse? (For this I got 10mcg/hr through ratio proportion)

I just wanted to know if there was a method I am unaware of to find these answers since all my other answers have been right up until this point. I also checked my dosage calculation book and that was not helpful for me so I came to the pros! Any help would be greatly appreciated!

[OlivetheRN, ADN, BSN, RN]

The way I would calculate these are to first figure out your mg (or mcg) per ml. From there you would just have to multiply the mg/ml by the ml/hr. Hope that helps :)

[SweetSouthernLove, ASN, BSN]

You just made it click for me! Thank you!!

[Boxer Mama]

I always use dimensional analysis. Since you gave an answer to question #2, I will help you with that one, then apply this method to the others to see if you can solve the problem.

1. First, write out the values:

ORDER (what the order is): 40mL/hr

HAVE (what you have): 1000 mg/500ml

KNOW (list any conversions needed):

2. Now, write down what you are solving for: xmg/hr.

3. Then from the above "have" and "know," pick the value what will put "mg" on the top and line up values for cross canceling.

xmg/hr: 1000mg/500ml x 40 ml/1 hr (these values should cross cancel to leave mg/hr as a way to double check that the problem is set up correctly)

= 4000/500

= 80 mg/hr

Hope that helped some (I am not the best at explaining. But, look up some other sites on dimensional analysis as ways to solve the calculations).

[pmabraham, BSN, RN]

Good day, SweetSouthernLove:

This is what I got using DA:

BTW, I found

to be a great video in learning how to use DA.

Thank you.

[auchiepie]

When in doubt dimensional analysis always works! Try to put the units you have on one side and on the other side of the equal sign put the units you want. For #1, when you cancel the ml (denominator) with the ml (numerator) you end up with (10,000 units x 10) / (500 x 1 hr) = 200 units per hr. You can use this canceling out method with almost every nursing calculation, aside drip factor rates. Math can be fun!

[Esme12, ASN, BSN, RN]

OP pmabraham has been very nice to you. It is the standard of this forum that student show their work first. Our goal is to help you become the best nurse you can be. I'm glad it clicked for you!