Maths Question IV Infusion

Daytonite, BSN, RN · Apr 8, 2009

a patient is ordered morphine infusion of 50mg. if the morphine is available in ampoule of 10mg/ml,

how many ampoules of morphine will be required to prepare the 50mg infusion?

50 mg

(dose desired)

/10 mg

(dose on hand)

=

5

(ampoules)

how many ml of 0.9% normal saline will be required to dilute the morphine to 1mg/ml?

since the dose is 50 mg. . .set up a ratio:

1 mg/ml = 50 mg/x ml.

. .

x

=

50 ml

laughingoutloud · Apr 9, 2009

Hi Thanks for the help but i actually got the 2nd part wrong, turned out the answer was 45 not 50...

But i appreciate the help :redpinkhe

Thanks alot

FlyingScot, RN · Apr 9, 2009

Hi Thanks for the help but i actually got the 2nd part wrong, turned out the answer was 45 not 50...
But i appreciate the help :redpinkhe
Thanks alot

Just to be sure you have a complete grasp of the calculation. Do you know why the answer was 45ml not 50?

EricJRN, MSN, RN · Apr 9, 2009

It's because you need 5 mL (5 ampules) of morphine to make 50 mg. So if you add the 5 mL (50 mg) to 45 more mL of saline, you'll end up with 50 mg of morphine in 50 mL of fluid (a 1 mg:1 mL concentration).

FlyingScot, RN · Apr 9, 2009

Eric, I knew that! I was just making sure the OP who was having difficulty with this calculation either knew it or could figure it out for herself. Just trying to close the loop.

Daytonite, BSN, RN · Apr 9, 2009

a patient is ordered morphine infusion of 50mg. if the morphine is available in ampoule of 10mg/ml,
how many ampoules of morphine will be required to prepare the 50mg infusion?
50 mg
(dose desired)
/10 mg
(dose on hand)
=
5
(ampoules)
how many ml of 0.9% normal saline will be required to dilute the morphine to 1mg/ml?
since the dose is 50 mg. . .set up a ratio:
1 mg/ml = 50 mg/x ml.
. .
x
=
50 ml
ok, i get it. i didn't finish the answer and that was my error and misunderstanding. to get the 45 ml, you subtract the 5 ml, which is what is the amount in the 5 ampoules of morphine, that will be need to be added to the saline. the total amount you want, however, will be 50 ml to give 1 mg/ml. you will need 45 ml of saline + 5 ml of morphine = 50 ml of morphine and saline that is diluted to 1 mg/ml.

FlyingScot, RN · Apr 9, 2009

Man, you guys are making it easy for the OP aren't you! :lol2:

Daytonite, BSN, RN · Apr 9, 2009

Man, you guys are making it easy for the OP aren't you!

That's what this forum is about. Helping.

FlyingScot, RN · Apr 9, 2009

That's what this forum is about. Helping.

Uh...sorry? That's what I thought I was doing. My bad.

Daytonite, BSN, RN · Apr 9, 2009

i just thought it a curious comment.

FlyingScot, RN · Apr 9, 2009

No not at all...if you notice there was a big grinning, laughing smiley after the sentence. When I see a post with something like that I don't usually associate it with someone being mean. In addition I asked the OP if she understood why 50mls was not the technically correct answer (although the correct total volume) to ascertain whether she had a good understanding of how to do the calculation in the future. It was a leading question to, hopefully, help her gain a better grasp of the concepts of medication calculation by helping her do it herself. Had she come back and posted I would have walked her through the problem on her own.I think she might have found that handy the next time she had to take a test and there wasn't anybody to assist her. I'm having trouble interpreting your intentions/emotions in your posts. I apologized with a question mark because I wasn't sure whether your posts directed at me were written matter-of-factly or with an edge to them. If it's the latter, I'm not entirely sure why you seem to be so angry with me. Perhaps we just have different teaching styles.