You gotta love math !!

[german_girl11]

Can someone please help me.

The doctor has ordered Dopamine infusion, pat. weighing 80 kg.

Concentration to be used is 400mg/250cc.

Doc wants to start infusion at 5mcg/kg/min

How many cc/hr would that be.

My calculation was: 400mg/250cc X 1000 / 60min / 80kg

So that would be 0.3.

Then 5mcg/kg/min X 0.3 = 1.5 cc/hr

AM I CORRECT ????

Thanks for all the help. So frustrating because I know its really not that hard.

[Music in My Heart]

You're close...

First, just look at how much Dopamine (and temporarily ignore how fast...):

5 mcg/kg x 80 kg = 400 mcg

Now get it into units consistent with how it's provided (milligrams, that is...):

400 mcg = 0.4 mg

Now go back to the rate... 5 mcg/kg/min = 400 mcg/min = 0.4 mg/min and then convert the minute-rate to an hourly rate

0.4 mg/min = 24 mg/hr

Now use the supplied concentration to convert the mass-flow rate (mg/hr) to a volume-flow rate (mL/hr)

24 mg/hr x (250 mL/400 mg) = 15 mL/hr

[german_girl11]

Thanks so much.

One more question though. Why is it 250ml/400mg and NOT 400mg/250ml in the end ???

[german_girl11]

And what if you need mcg/min.

50mg in 250cc. Start at 10cc/hr.

I need to go back to school

[Esme12, ASN, BSN, RN]

DosageHelp.com - Helping Nursing Students Learn Dosage Calculations

DosageHelp.com - Helping Nursing Students Learn Dosage Calculations - Mass/Time - IV mL Rate Questions

https://allnurses.com/nursing-student-assistance/med-math-examples-786141.html

there are certain essential parts to every equation.......

d= dose ordered

a=available strength

q=quantity of medication that has that strength

desired dose x on hand

quantity/concentration = to be given

The doctor has ordered Dopamine infusion, pat. weighing 80 kg.

Concentration to be used is 400mg/250cc.

you have 400mg of dopamine in 250cc of solution.

You need 5mcg/Kg: 5 mcg/kg x 80 kg = 400 mcg

400mcg is equal to how many mg.......0.4mg right?

Now you need... 5 mcg/kg/min which is 400 mcg/min which is 0.4 mg/min and then convert the minute-rate to an hourly rate

0.4 mg/min x 60 (min in an hour) equals 24 mg/hr

Now use the supplied concentration(400mg in 250cc) to convert the mass-flow rate (mg/hr) to a volume-flow rate (mL/hr)

24 mg/hr [desired dose] (250 mL[fluid on hand]/400 mg[drug avail]) = 15 mL/hr

[ADN2B]

250mL/400mg x 1mg/1000mcg x 400mcg/1min x 60min/1hr=15mL/hr

[Esme12, ASN, BSN, RN]

250mL/400mg x 1mg/1000mcg x 400mcg/1min x 60min/1hr=15mL/hr

Dimensional analysis.....http://www.davesems.com/files/drug_dose_calculations.pdf

[Music in My Heart]

Thanks so much.

One more question though. Why is it 250ml/400mg and NOT 400mg/250ml in the end ???

Think about what we know:

Docs don't order medication by volume because then the actual amount of the active component depends on the concentration. They order it by the actual amount of medication.

The pharmacists or drug companies don't count out every molecule, they just weigh out a certain amount and add that to a certain volume --- that is, create a solution of a certain concentration.

In this case, we know that the doc wants 24 mg of Dopamine to flow into the patient each hour... well, since you cannot control the mass flowing in, you need to determine what volume of solution has those 24 mg. You do this by dividing by the concentration (or algebraically, inverting and multiplying).

Looking at the units, if you multiply by 400mg/250mL, your units won't cancel and you'll end up with mg*mg/mL/hr...