Drug Calculations problem.

[RN_Pink]

This isnt homework, its just practice and its my very last question. I cannot figure out how my teacher got her answers. Will someone please show me how to work this out.

The physician orders Dobutamine 250 mg in 250 mL of D5W to infuse at 5 mcg/kg/min. Your patient is 80 kg and your administration set is 60 gtts/mL. What is the rate of the flow in ml/hr and gtt/min.

I know the answer is 24 ml/hr & 24 gtt/min but I have used the formulas and cannot get this answer.

Thanks!

[dienne]

here it is:

ml/hr = 250ml/250mg x 400mcg/1min x 60min/1hr x 1mg/1000mcg = 24ml/hr

gtt/min - 250ml/250mg x 400mcg/1min x 60gtt/1ml x 1mg/1000mcg = 24gtt/min

[MunoRN, RN]

The first step is to find the dose per pt weight, (5mcg/kg) so 5x80=400. So now you know that the dose is 400mcg per minute for this patient.

You can now figure this per hour, so 400 x 60 minutes = 24,000 mcg/hr.

To change this to mg/hr from mcg/hr, move the decimal point three places to the left (there are 1000 mcg in 1 mg), which gives you 24mg/hr.

You now need to change this dose/hr into volume/hr using the concentration of the fluid, which luckily in this case is 1mg:1ml, so 24mg/hr = 24 ml/hr.

At this point the correct answer is that you never run dobutamine without a pump using only a drip calculation, this isn't 1960.

But for random nursing history trivia purposes, if you were to figure for gtt/minute, you could just remember that a 60gtt/ml drip rate will be a 1:1 ratio of drips per minute to ml/hr, since to find the gtt/minute you will multiply the number of drops in a ml by the number of ml/hr, then divide that be 60 to get the number of drops per minute, (multiplying and then dividing by the same number cancels each other out, leaving you with the original number).