# Calculation Rule.....Help

Posted

Specializes in ER, Med/Surg, LTC. Has 10 years experience.

All Nurses:

Could you please tell me the how to calculate this problem please, I need easy to remember instructions.....thank you in advance.........

A septic client with hypotension is being treated with dopamine hydrochloride (Inotropin). The nurse asks a colleague to double-check the dosage that the client is receiving. There are 400 mg of dopamine hydrochloride in 250 ml, the infusion pump is running at 23 ml/hour, and the client weighs 79.5 kg. How many micrograms per kilogram per minute is the client receiving?

Specializes in ER, Med/Surg, LTC. Has 10 years experience.

Nevermind, upon reviewing the question, I see where it says to convert to micrograms......getting nervous, testing in a couple of days......:smackingf

Specializes in Telemetry, Med-Surg.

HI Kazaa,

This is a multistep problem. There are no "easy to remember" instructions for this. You're really going to have to just know your conversions. I am so not sure if I solved it right, but I came up with 7.8mcg/kg/min using rounding rules...my decimal may be alittle off since I rounded. Do you have the answer key? I won't share what I did just in case its wrong. lol Please share the answer if you have it.

shescoolie- be confident you are correct! 7.71 mcg/kg/min

Specializes in Telemetry, Med-Surg.

*UPDATE*

I was so bothered by this problem that I googled it. Turns out someone has asked this same question on allnurses before. It appearantly is an NCLEX 3500 question.

BTW I was right! :)

Here's what I did, which is a little diffent from some of the ways listed in the link above.

Solve for how many mg per hour infused knowing 400 mg/250ml over a 23 hour period:

400mg/250ml=x/23ml

Gives you 36.8 mg per hour

Now convert mg to mcg:

36.8mg/1 hour=x mcg/1 hour

Gives you 36800mcg or 37000 mcg if you round. Lets stick with 36800mcg

Now solve for how many of these mcg the patient will get per minute, so 60 minutes in 1 hour:

36800mcg/60minutes= 613.3 rounded to whole number 613mcg/min

Now we know there are 613mcg infusing per minute on a pt who weighs 79.5kg.

Simple divide 613/79.5 to get 7.71 mcg/kg/min

Hope this makes sense!

Specializes in ER, Med/Surg, LTC. Has 10 years experience.

Rationale:

First, calculate how many micrograms per milliliter of dopamine hydrochloride are in the bag: 400 mg/250 ml = 1.6 mg/ml.

Next, convert milligrams to micrograms: 1.6 mg/ml x 1,000 mcg/mg = 1,600 mcg/ml.

Finally, calculate the dose: 1,600 mcg/ml x 23 ml/hour/79.5 kg

79.5 kg/60 min/hr = 7.71 mcg/kg/min.

Thank you Shescoolie and Hooter44.............

Specializes in Telemetry, Med-Surg.

You're welcome! YOUR way is soooo much easier! lol

Specializes in ER, Med/Surg, LTC. Has 10 years experience.

Thanks Shescoolie, I do believe I prefer your explanation better, much easier to remember.......I had just completely ignored the last part of the question and ignored where it said convert to micrograms.......:)

Math problems, headaches for many of us!

Kazza hello, I did not recieve disc could u try to resend my address is 170 cotton bayou ln monroe la 71202

Specializes in ER, Med/Surg, LTC. Has 10 years experience.

Send me your name and address again, I did send it to you, I was wondering why you never sent a message to say thank you. No problem.........