Can someone help solve this problem

stbernardclub · Nov 27, 2004

61.6 OR 62

The physician orders 5mcg/kg/min of dopamine for an 80 kg patient.
You put 400mg of Dopamine in 250mls D5W. What is the correct rate
using microdrip tubing
can someone do the steps to get to this answer thanks
Is this the right answer 15gtts/min?

Kir · Nov 27, 2004

61.6 OR 62

oh man... :imbar I am mucho confused! Could you please post the formula used? I got all messed up when there was no time frame listed. Should the patient get 5mcg/h or min or day/lifetime... It is the time frame that is throwing me off. Math is the bane of my existance.

TweetiePieRN · Nov 27, 2004

the physician orders 5mcg/kg/min of dopamine for an 80 kg patient.
you put 400mg of dopamine in 250mls d5w. what is the correct rate
using microdrip tubing
can someone do the steps to get to this answer thanks
is this the right answer 15gtts/min?

i got the same answer as you and worked it out 2x. i am going to try my best to explain how i got the answer. this would be a ton easier to explain in person, but here goes!

1st: i like to convert everything so that i can go straight thru the problem.

5mcg/kg/min dopamine. pt weighs 80kg, so you multiply the 5mcg by the 80 and you get 400mcg/min dopamine for the dose.

2nd: there is 400mg of dopamine in 250ml d5w. i want to convert the 400mg to mcgs since the pt dose is expressed in mcgs. there are 1000mcgs in 1 mg. multiply 400mg by 1000 and you get 400,000 mcgs dopamine in 250 ml d5w. on paper it looks like 400,000 mcgs dopamine

250 ml d5w.

if you reduce this equation to its simplest terms. it makes this whole problem a bit simpler. it becomes 1600 mcg per 1ml of d5w

3rd: microdrip tubing is 60 gtts/min.

4th: using factor-label method, i can then figure out the problem. essentially the problem wants to know: how many gtts per minute of mixed solution. the mixed solution is the d5w and dopamine together.

it would look like this:

400 mcg dose dop.x 1 ml d5wx 60 gtts

........1 minute....1600mcg dop...1 ml

the label of "mcg" cross cancels the other "mcg" out. so does the ml label. so you end up with the word "gtts" on the top lines and "minute" on the bottom. you wanted gtts/min. multiply all the numbers on the tops (400x1x60=24,000) divide by the numbers on the bottom (1x1600x1=1600) you end up with 15 gtts/min!! does this make sense?

preciousshelby · Nov 27, 2004

The physician orders 5mcg/kg/min of dopamine for an 80 kg patient.
You put 400mg of Dopamine in 250mls D5W. What is the correct rate
using microdrip tubing
can someone do the steps to get to this answer thanks
Is this the right answer 15gtts/min?

The following is the way I figure it out, I have been taught by a pharmacist long ago while I was a Paramedic and have continued it through my nursing career. It makes sense to me, you see it all on paper in front of you rather than memorizing formulas (which I can't stand):

(60gtts) . (250cc) . (400 mcg) . (1mg) = Gtts/min

cc 400 mg min 1000mcg

The first paranthesis is your drip factor, the second is your concentration and the third is how many mcg per min (after kg was calculated) and finally your conversion of 1mg/1000 mcg. Then you cross multiply, cancelling like figures (such as the cc on the bottom cancells the cc on the top of the 2nd, etc) and what you have left is what you want---gtts/min. And yes, the answer is 15gtts/minute.

This drives my husband batty because he is a Paramedic who can memorize those formulas like no tomorrow, but this works in ALL cases, young, old etc

Good luck and hope this helps!!!

XIGRIS · Nov 27, 2004

15 cc/ min is correct. 62 ..... thats very very high.. almost 50 mcg/kg/min... very lethal... max dose for DA is 20 mcg/kg/min... if it doesnt help the blood pressure change it to a different pressor... its just not gonna work...