Patient weighs 170 pounds who requires a dopamine drip. Need calculation help!

I have this due on Tuesday which is my first day back. I feel as though I have forgotten all of my calculations. Here is the problem and how I did it. Please tell me if I did it correct or where I went wrong.

Pt. weighs 170 pounds who requires a dopamine drip for a failing kidney. Protocol dictates that you start the drip at 5mcg/kg/min. You want to mix a drip that contains 400 mg of dopamine in your 250 ml bag of normal saline. How many ml/hr will you infuse?

170/2.2=77.27=77.3 kg

77.3 kg* 5mcg/min*60 min= 23190mcg/min=.057 round to .1*250ml=25ml/hr

400000mcg 400000 mcg

Not sure if I did any of this correct. Help.

[loveofrn, BSN, RN]

The answer is 14.5ml/hr

[loveofrn, BSN, RN]

How did you get 0.57

And again why did you round 0.057 to 0.1

[loveofrn, BSN, RN]

Ok here is how I did mine

(5mcg/kg/min)×(250ml/400000mcg)×(60min/hr)×(77.3kg)=14.5ml/hr

That was my original answer. I originally converted the 23190 mcg to mg then divided that by 400mg then multiply by 250ml

23.19*250ml=14.49=14.5

400

Is that the correct way?

I did not come out with 0.057. I did 23190

400000

I converted the 400mg to mcg. Not sure why.

[loveofrn, BSN, RN]

Always check your unit whenever you are doing dosage math. Also do you know how to use dimensional analysis

[loveofrn, BSN, RN]

And your answer is correct

[loveofrn, BSN, RN]

Yes you suppose to convert 400 mcg to mg to track your unit

It was 400 mg to mcg. By the way, I hate dimensional analysis. Just do.

[loveofrn, BSN, RN]

Lol just make sure you know what you are doing. Just stick with the method that works for you

Thanks so much for your help.

[loveofrn, BSN, RN]

You're welcome

[Esme12, ASN, BSN, RN]

my favorite site....DosageHelp.com - Helping Nursing Students Learn Dosage Calculations

[pmabraham, BSN, RN]

Good day, b747girl5:

Generally you don't want to round until the end to avoid mistakes.

Thank you.

[Kuriin, BSN, RN]

Unless stated otherwise, you should do as pmabraham said and round only at the end.

I did this

170lbs = 77.3 kg

5mcg/kg/min= 3865mcg/min

which converts to 0.3865 mg/min

then

400 mg/ 250 ml = 0.3865 mg/x ml

and cross multiply

x = 0.24 ml/ min

multiply by 60 to get 1 hour

14.493 rounded to 14.5 ml/hr

The answer is 14.5ml/hr.

400mg=400,000 mcg

170 lbs=77.3 kg

(77.3 kg * 5 mcg/kg/min=387 mcg/min)

(387 mcg/min * 60 min/hr=23,220 mcg/hr)

(250 ml/400,000 mcg * 23,200 mcg/hr)=14.5 ml/hr

Hope the break down helps.