Clinical Math IV question- HELP!!

i have been working on getting this iv math down for a few days now- i am confused- my book says that if you have any drug that exceeds 5 ml that it should be added to the dilution volume in intermittent drug therapy

sooooo

then they present a problem in my text as such...

order ticarcillin 500 mg, iv q6h

drug on hand 1,000 mg = 4 ml

set and solution: buretrol set with a drop factor of 60 gtt/ml; infusion pump; 500 ml of d5w

instructions: dilute drug in 75 ml of d5w and infuse over 40 min

1)amount of drug ( as per my calculations) needed 2ml

2) flow rate (gtt/min)

since it is under 5 as per my book does not need to be added to dilution i would do the following:

75/40 (x) 60 = 112.5 gtt/min

3) infusion pump rate( ml/hr )

75 divided by 40(time given)/60 (min) so my math comes out as 112.5 ml/hr or 113 ml per hour

however, in the back of the book they added the 2 ml to the dilutent so problem #2 came out as 116 gtt/min and #3 116 ml/hr

next problem

order methicillin 1g iv q6h

drug available 4g in 8 ml

set and solution: secondary set with a drop factor of 15 gtt/ml; 100 ml bag of d5w; infusion pump

instructions dilute drug in 100 ml of d5w and infuse over 40 minutes

1) drug calculation 2 ml

2) flow rate ( gtt/min)

100/40 (x) 15 = 37.5 or 38 gtt/min

3) infusion pump ( ml/hr)

100 divided by 40/60 =150 ml/hr

so this problem all the above answers are right but does not add the 2ml of the drug to the dilutent total

please help- i am confused why one situation added the 2 ml and the other didn't. i would have of course added it, if it were over 5ml as per the book but dont understand why one is added to the total and the other is not

thanks for your help!

i am working out of the purple clinical calculations w/ applications to general and speciality areas 6th edition by kee and marshall pages 240-241 if you are interested or have the same book

im just curious....

why do we ask questions like this in exams? most of the hospitals in us have infusion pumps. and most drugs are mixed by pharmacy which includes how fast you run the drug. i understand calculating for dose yes.. i rechecked my dose even if i use pump when i infused vasoactive agents but asking how much flow rate??? for antibiotics??? just curious....

when you start working you are going to use an iv tubing specific for an infusion pump, you are not gonna have a micro or macro drip factor that you have to know and calculate... the pump will run your antibiotic safely.

do they ask this in the nclex exam?

instead of asking this type of question.... why not focus on teaching the mechanisms of the drug. if one knows the mechanism of a certain drug then we may know the pharmacodynamics and pharmacokinetics.

In your first problem, you have 2 ml of medication that needs to be diluted, so you add it to your 500ml bag...hence you have more than 500ml...you have 502ml.

In your secondary problem, the key word was secondary set. A secondary set usually means that you are piggybacking the medication to run concurrently with the D5W and is being diluted that way. You aren't adding the medication to the bag.

Im just curious....

Why do we ask questions like this in exams? Most of the hospitals in US have infusion pumps. And most drugs are mixed by pharmacy which includes how fast you run the drug. I understand calculating for dose yes.. I rechecked my dose even if I use pump when I infused vasoactive agents but asking how much flow rate??? for antibiotics??? Just curious....

When you start working you are going to use an IV tubing specific for an infusion pump, you are not gonna have a micro or macro drip factor that you have to know and calculate... the pump will run your antibiotic safely.

Do they ask this in the NCLEX exam?

Instead of asking this type of question.... why not focus on teaching the mechanisms of the drug. If one knows the mechanism of a certain drug then we may know the pharmacodynamics and pharmacokinetics.

At what level of your schooling do these test come into the picture? Thank goodness for XIGIS response, I almost thought being an elementary school teacher might be a better program for me.

I did not read through the question, but I can tell you what my instructor has us do for our math exam (which is quickly approaching :uhoh21:). She will accept both answers, whether you add in an amount less than 5 ml or not. Her thinking is that adding in a smaller amount makes the dosage more accurate and will not penalize us for it. I would try to find out if your instructor does the same.

I have the exact same book and have asked myself the Exact same question you are to my clinical instructor. I will certainly let you know when I find out!