Drug Calculation Problem (Niroprusside)

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I've been struggling with this problem for my test next Thursday, and I'm wondering if anyone could help me out and tell me the rationale. My professor didn't go over it in class because of " time restraints".

any help would be appreciated!

Problem:

ORDER: IV Nitroprusside 0.3 mcg/kg. Available: 50 mg in 250 mL NS. Patient weighs 300 lbs.

What rate (mL/hr) should the IV pump be set to administer 3 mcg/kg/min?

Use the link provided to obtain the answer:

http://www.globalrph.com/drip.htm

Please show us what you've done so far.

Also, I went to the link and it's really easy to get the answer but you won't actually learn how to do it so not at all sure why your instructor would have you do it that way.

Specializes in OR, Nursing Professional Development.

These kinds of problems are best broken down into steps. What are some of the steps you think you need to take to solve the problem? Think about what units

the dose is ordered.

Order: 0.3 mcg/kg

Available: 50 mg/250 mL

Pt weight: 300 lbs

You need to convert lbs to kg - You can do that before or you can do that in the problem. I just usually do it in the problem because it makes one less step. But a lot of people like to do it before.

300 lbs = 136.36 kg

You set up the problem by starting off with what is ordered: the mcg/kg/min.

First, you need to cancel out the kg. You do that, by converting the pts weight (300 lbs) into kg. If you didn't do this before, you can do this using a conversion factor - 1 kg = 2.2 lbs - to cancel out the kg. Then use the pts weight to cancel out the lbs.

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Then, you need to cancel out the mcg. You do that by using a conversion factor. In this case, you would use 1000 mcg = 1 mg. So, you have canceled out mcg by converting it to mg.

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You canceled out the kg. You canceled out lb. You canceled out the mcg by converting mcg to mg. So, now you are left with mg/min.

You need to cancel out mg and min - because you want mL/hr.

To cancel out the mg and be left with mL, you use what is available - 50 mg/250 mL.

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To cancel out the min, you need another conversion factor - how many min are in an hr = 60 min/1 hr.

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So, now you are left with mL/hr. You just calculate across the numerators, across the denominators, and then divide. You are left with your answer of 12.27 or 12.3 mL/hr.

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