# Math question. - page 2

Your patient is receiving a Lidocaine drip of 1.0 g/500 cc fluid. If your drop factor is 15 gtts/cc, what rate in cc/hr should the infusion run to deliver 2 mg/m? I found this question online. ... Read More

1. Thanks Daytonite for the reminder it's going to take many of these to get good!

One question though, What is dose on hand vs amount on hand? (I get that the total amt is 250 (dose on hand) but what did you mean by the amt the 250mg is reconstituted in? Is that something that would be given in the problem or something that you just learn as a nurse? It's true the math doesn't seem like it would be that far above me it's just learning the formulas.
2. DA finally clicked today due to an excellent instructor who said do it this way:

1: What do you want to determine?
2: What do you have?
3: What are the conversion factors (if any)?
4: Plug in the numbers and solve the problem.

Man, does that work. I am currently listing all possible conversion factors and then eliminating those I don't need. The instructor said that it'll soon just become second nature to choose the needed factors. Cool stuff. No formulas :wink2:
3. Quote from kittyhawk
What is dose on hand vs amount on hand? (I get that the total amt is 250 (dose on hand) but what did you mean by the amt the 250mg is reconstituted in? Is that something that would be given in the problem or something that you just learn as a nurse? It's true the math doesn't seem like it would be that far above me it's just learning the formulas.
The dose desired is what you are ordered to give the patient. The dose on hand is the formulation of this drug you have on hand. The amount is the amount that the dose on hand comes in. This amount can be tablets or liquid. The problem I was using as an example was a real world situation where you would know that the drug dosage on hand was contained in the vial of medication that was reconstituted.

Here's another example of how to use that formula using tablets. This is one of the most common orders a nurse sees on a patient's chart. Let's say the doctor has ordered Tylenol 650mg orally for the patient. You have Tylenol in tablets of 325mg. How many tablets will you give the patient? Using this forumula:
650mg (dose desired) / 325mg (dose on hand) X 1 tablet (amount that each dose comes in) = 2 tablets
Tylenol also comes in a liquid form. So, if you have an adult with a gastric tube who has a fever and needs to be given Tylenol 650mg via the gastric tube for this fever and what you have in your medicine cart is Tylenol Elixir (the liquid form of Tylenol) which has 120mg per every 5mL., how much Tylenol elixir are you going to give this patient?
650mg (dose desired) / 120mg (dose on hand) X 5mL (amount that each dose comes in) = 27.0833mL or 27mL (rounded off)
4. Daytonite, thanks so much for replying. You could easily brush the questions off and/or say I'll get it when I get to nursing school, but I'd like to have somewhat of a foundation on the math before I start, hopefully next Fall. You really care about the success of other future nurses, that comes across in your posts...and that's really cool. I get your explanation perfectly, so I will print it out and use for reference when I'm working through the nursing math books. Right now I'm consumed with Chem stuff, but I figure if I can figure out how many meters light travels in an hour....I should be able to figure this med stuff out!

Thanks again, your input is invaluable.

Michele
5. Quote from kittyhawk
Daytonite, thanks so much for replying. You could easily brush the questions off and/or say I'll get it when I get to nursing school, but I'd like to have somewhat of a foundation on the math before I start, hopefully next Fall. You really care about the success of other future nurses, that comes across in your posts...and that's really cool. I get your explanation perfectly, so I will print it out and use for reference when I'm working through the nursing math books. Right now I'm consumed with Chem stuff, but I figure if I can figure out how many meters light travels in an hour....I should be able to figure this med stuff out!

Thanks again, your input is invaluable.

Michele
I agree. She's helped me out a whole lot, THANKS, Daytonite!!!

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