Math Help for Returning Nurse

KelRN215, BSN, RN · Jan 15, 2012

3.75 what? The answer needs to have some kind of label for it to be a valid answer.

This is how I would approach this problem:

You have 2mg/500 mL. Your ordered rate is in mcg/min. 2 mg = 2000 mcg. 2000 mcg/500 mL= 4 mcg/mL.

1 mL/4 mcg x 5 mcg/min= 1.25 mL/min x 60 min/1 hr = 75 mL/hr

You can also figure out that 5 mcg/min will be a rate of 300 mcg/hr. (5 mcg/min x 60 min/1 hr = 300 mcg/hr) You know that your concentration is 4 mcg/mL so:

1 mL/4 mcg x 300 mcg/hr = 300/4 = 75 mL/hr.

I am failing to see where the answer of 3.75 could possibly come from.

RNrerun · Jan 15, 2012

Thank you for your help. I'm an idiot. The 3 was the number of the problem, so yes the answer was 75. I just couldn't figure how to write it. I'm going to study your example and work on more of the practice problems and hopefully this is going to click for me!! Thanks so much!

IVRUS, BSN, RN · Jan 16, 2012

For me this is a simple want/have times volume question:

want = 5mcg times 60min in an hour which equals 300mcg per hour.

have= 2000mcg and a volume of 500ml

300 divided by 2000 then times 500 = 75mls/hr.

RNrerun · Jan 16, 2012

Thank you IVRUS! The want/have times volume formula will be a big help to me!

JROregon, ASN, BSN, RN · Jan 17, 2012

Ever since I heard about dosagehelp.com, I have been breezing through these questions. Amount or rate needed / what you have on hand x number of mls (cc's) in the vial, bag, or whatever.

(0.005 mg(mcg converted to mg) / 2 mg) x 500 cc/mLs = 1.25 mLs/minute x 60 = 75 mLs/hr.

Go through the mass/time - IV rate practice questions. Good luck.

RNrerun · Jan 17, 2012

Thanks so much JROregon for the site! I will be doing the practice questions! (Boy, I wish this stuff had been around in the dark ages, back when I was in nursing school!)