# Dosage test...concentration problem

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Please help! I am studying for an advanced dosage calculation test and am stuck on one set of the problems. One problem is as follows: heparin 25,000 units in 250 mL D5W @ 1000 units/hr.

We have to answer the following questions: what is the concentration, what would be the vol/min, what would be the concentration/min. If anyone can help me with this problem, I can figure out the rest. I've looked in my text books but we briefly covered this the beginning of last semester and I can't find my notes anywhere. Thank you in advance!!!

Specializes in L&D, infusion, urology. Has 2 years experience.

What do you have so far? What do you think the answers are?

We're happy to help, but we won't give you the answers. We will, however, offer guidance with answers you've come up with. :)

Ok, I think concentration would be 25,000 units divided by 250 mL. So this would be 100 units per mL. Then vol per min would be 250 mL divided by 60 mins (1hr)? So does this mean the answer would be 4.2 mL per minute?

Ok, I think concentration would be 25,000 units divided by 250 mL. So this would be 100 units per mL.

This part is correct.

Then vol per min would be 250 mL divided by 60 mins (1hr)? So does this mean the answer would be 4.2 mL per minute?

If you do this, how many units/hour will the patient receive?

Wait, never mind. I think volume per minute would be 1000 units equals 10 mL divided by 60 min. This would mean the answer is 0.17 mL per min.

Yes. If there are 100 units/cc (this is correctly figured), how many of those cc will make 1000 units, which is what you want? And that's how many cc/hr, isn't it? The 1000 units? Then you can divide that by 60 minutes, which is your 0.1666666 (0.17cc) / minute.

Hint: It makes no difference how many cc there are in the bag once you have figured out how many units/cc is in the solution.

And please go change your posting name to something anonymous stat! You will thank us later for that advice. 10? (1000/100)

Thank you!!!! I'll do that real quick. Be right back.

Specializes in MICU. Has 3 years experience.

10? (1000/100)

10 is ml/hr, you need ml/min

Ok so vol/min = 0.17 mL per min?

Thank u. I just saw the rest of your response. I'm using an iPad and it didn't show all of it to begin with. I'm not sure where to begin on concentration per minute. Would you just multiply the 0.17 mL by the 100 units per mL?

Specializes in MICU. Has 3 years experience.

Ok so vol/min = 0.17 mL per min?

Since concentration is 100ml/hr and 0.17 is ml per min,

then what is the concentration per min?

17 units per min?

That is correct Grasshopper.

Since concentration is 100ml/hr and 0.17 is ml per min,

then what is the concentration per min?

It's not "concentration per minute," it's dose per minute. Concentration is not a time-dependent variable. Didn't you take chemistry? If not, you will have to. I hope.

Specializes in MICU. Has 3 years experience.

It's not "concentration per minute," it's dose per minute. Concentration is not a time-dependent variable. Didn't you take chemistry? If not, you will have to. I hope.

It was a typo and yes, I took chemistry

Edited by loveofrn