Help with med math problem

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The Dr. orders 1gm Kefzol IV q8 hr. The med is reconstituted in 50mL NS and pharmacy instructs you to run it over 15 min. Calculate the pump rate in ml/hr?

50ml/8hr X 1hr/60 x 15gtt= 1.56 this is wrong

the correct answer is 200 but I don't know how the book got this answer

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Emilyemily, you really have a hard time with these things. I strongly suggest you use some sort of visual aid to help you think about it before you start plugging numbers into a formula willy-nilly, because there's no point in using a formula if you don't know why and how you're using it.

Draw a picture. A little circle will do, but if you're artistic, make it look like a minibag. Label it "50cc," because that's what the pharmacy has sent you. It doesn't matter how much drug is in it at all. Could be 1gm, could be 18 gm, could be 346.9 gm, because all they are asking you to do is figure out cc/hour. There is no measure of weight in that.

Draw a clock face. Shade in "15 minutes." That's how long that 50cc bag has to be all gone.

Now, how many 15-minute periods are there in an hour? Can you see that the answer to that is "4"?

If you ran 50cc four times in an hour, how many cc would that total? Can you see the answer would be 4x50 = 200? Can you see that if you are running your 50cc minibag at 200cc/hour, it will be all gone in 15 minutes?

If 50cc is gone in 15 minutes, how many cc would be gone if it ran for a whole hour?

Look at it another way:

50cc = 15 minutes

? cc = 60 minutes

Can you see that the gtt factor doesn't make any difference at all? If it is 1gtt/cc (big gtt!) or 100 gtts/cc or 10,000gtts/cc, you don't need to know that, because all they are asking you about is cc/hour.

I just do not know how to make this any clearer.

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Specializes in Gerontology.

Grn Tea beat me to it!

You got the wrong answer because you are not using the fomula correctly.

Why did you divide 50ml by 8 hrs?

And why factor in the gtt rate?

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Emilyemily, look at your answer. You have 50cc to give one time every eight hours, and you are giving them at a rate of less than 2cc in an hour. How many hours is that going to take? Is that remotely close to 15minutes?

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Specializes in Pedi.
The Dr. orders 1gm Kefzol IV q8 hr. The med is reconstituted in 50mL NS and pharmacy instructs you to run it over 15 min. Calculate the pump rate in ml/hr?

50ml/8hr X 1hr/60 x 15gtt= 1.56 this is wrong

the correct answer is 200 but I don't know how the book got this answer

You have this set up completely wrong. There is no drop factor in this problem. At all. Where did you get 15 gtts from? You are not running 50 mL over 8 hours- you are running 50 mL over 15 minutes q 8hr. The ONLY thing you need to know to figure out this problem is that you are running 50 mL/15 min. 15 minutes is 1/4 of an hour so you need to run the rate at 4x 50 mL to infuse 50 mL in 15 minutes. That's where 200 comes from.

Look at the way you have your problem set up- the units of your answer would be mL*gtt/min. That's no good. You have posted many times on here looking for help with basic math problems- you might consider looking into tutoring.

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Also 8 hrs is pointless.

When you look at these problems you need to pick and choose which info you need and which you don't.

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.
The Dr. orders 1gm Kefzol IV q8 hr. The med is reconstituted in 50mL NS and pharmacy instructs you to run it over 15 min. Calculate the pump rate in ml/hr?

50ml/8hr X 1hr/60 x 15gtt= 1.56 this is wrong

the correct answer is 200 but I don't know how the book got this answer

They give extra stuff that you don't need. I have highlighted the only information necessary for solve this problem

You need to give 50mls over 15 mins. How fast do you set the pump.

Now.....do the calculation......bag size X (60/time in minutes to infuse bag over)

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Emilyemily, you really have a hard time with these things. I strongly suggest you use some sort of visual aid to help you think about it before you start plugging numbers into a formula willy-nilly, because there's no point in using a formula if you don't know why and how you're using it.

Draw a picture. A little circle will do, but if you're artistic, make it look like a minibag. Label it "50cc," because that's what the pharmacy has sent you. It doesn't matter how much drug is in it at all. Could be 1gm, could be 18 gm, could be 346.9 gm, because all they are asking you to do is figure out cc/hour. There is no measure of weight in that.

Draw a clock face. Shade in "15 minutes." That's how long that 50cc bag has to be all gone.

Now, how many 15-minute periods are there in an hour? Can you see that the answer to that is "4"?

If you ran 50cc four times in an hour, how many cc would that total? Can you see the answer would be 4x50 = 200? Can you see that if you are running your 50cc minibag at 200cc/hour, it will be all gone in 15 minutes?

If 50cc is gone in 15 minutes, how many cc would be gone if it ran for a whole hour?

Look at it another way:

50cc = 15 minutes

? cc = 60 minutes

Can you see that the gtt factor doesn't make any difference at all? If it is 1gtt/cc (big gtt!) or 100 gtts/cc or 10,000gtts/cc, you don't need to know that, because all they are asking you about is cc/hour.

I just do not know how to make this any clearer.

You explained this very well. :)

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I would like to add:

We are told, the reason we are always asked how fast something infuses in an hour is because EVEN though the MD says run it (mL) over 15, 30, 20, 10 etc. minutes....

The pump only understand mL/hr

So if the doc says infuse 100 mL in 30 minutes, you tell the machine to infuse 200mL in ONE hour because that will infuse the 100mL bag in the 30 minutes as ordered.

Maybe if you know the WHY you understand a bit more....

0 Votes
Specializes in Pedi.
I would like to add:

We are told, the reason we are always asked how fast something infuses in an hour is because EVEN though the MD says run it (mL) over 15, 30, 20, 10 etc. minutes....

The pump only understand mL/hr

So if the doc says infuse 100 mL in 30 minutes, you tell the machine to infuse 200mL in ONE hour because that will infuse the 100mL bag in the 30 minutes as ordered.

Maybe if you know the WHY you understand a bit more....

There actually are plenty of pumps that you could just set to infuse 50 mL in 15 minutes. All of the pumps we used could be set as either volume/time or mL/hr when I worked in the hospital. Also, it's typically the pharmacy- not the MD- telling you how fast to infuse a medication.

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ml/hr= 50ml/15min x 60min/1hr = 200

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how i do it,, 50 times 60 divided by 15 equals 200.... just use the volume times 60 min divided by minutes u will run it, 15.

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