# Dosage Calculations

Posted

I am in a desperate situation. I thought I was getting my calculations correctly and today I got back my math results and i got a 70% I am so disappointed I dont know what to do. On my first exam I received an 80%.

My professor said that if i get above 95% on my final (which is next week) I may be able to average a b+ or a- , but it will all depend on the overall average, if he curves grades or not. I went and bought 2 self help books on calculations .... My question is ..... do you think it is humanly possible to ingest all this info by next week (exactly a week from today)! I am having problems with the drips and the three step conversions. Is there a website that can help me? To top it off my professor sucks, so what I have learned, I have learned on my own. I am so frustrated, so much so, that it is getting harder and harder for me to pick up a book .....sorry for venting

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189 Posts

Thanks for the responses. Janet my book didn't come with a cd.

I do have a problem that I am stuck with... here it is

Nitrostat 8mg in 250 mL of 5% D/W/ IVPB. Infuse at rate of 8 mcg/min. Calculate the flow rate in drops per minute. The drop factor is 6ugtt/mL.

I am drawing a complete blank with this one

Specializes in Gerontological, cardiac, med-surg, peds. Has 16 years experience. 105 Articles; 5,349 Posts

Nitrostat 8mg in 250 mL of 5% D/W/ IVPB. Infuse at rate of 8 mcg/min. Calculate the flow rate in drops per minute. The drop factor is 6ugtt/mL.

I assume instead of "6ugtt/mL" you mean 60 gtt/ mL?

60 gtt/mL X 250 mL/8mg X 1 mg/1000mcg X 8 mcg/min =

120,000 gtt/8000 min

15 gtt/min

189 Posts

VickyRN said:
Nitrostat 8mg in 250 mL of 5% D/W/ IVPB. Infuse at rate of 8 mcg/min. Calculate the flow rate in drops per minute. The drop factor is 6ugtt/mL.

I assume instead of "6ugtt/mL" you mean 60 gtt/ mL?

60 gtt/mL X 250 mL/8mg X 1 mg/1000mcg X 8 mcg/min =

120,000 gtt/8000 min

15 gtt/min

Yes I meant 60 gtt:chuckle Thank you very much!!!!

I am studying all day today I hope you dont mind if I keep posting questions!!! Thanks!!!!!

178 Posts

i just started to learning these types of question for nursing 4 lol

this is how i do it:

8mcg/min x 1/8000mcg x 250/1 x 60gtt/ml

really ratio propertion works for me. can't go wrong

- janet

Specializes in Gerontological, cardiac, med-surg, peds. Has 16 years experience. 105 Articles; 5,349 Posts

minnielynn said:
i have another one:

a.

the order is ivpb 500 ml 0.9% sodium chloride with 20 units of pitocin to be infused at a rate of 4 mu per minute. calculate the flow rate in microdrops per minute:

60 gtt/ml x 500 ml/ 20 units x 1 unit/ 1000 mu x 4 mu/ minute = ???

b.

the order has been increased to 7 mu/min. recalculate the flow rate in microdrops per minute.

60 gtt/ml x 500 ml/ 20 units x 1 unit/ 1000 mu x 7 mu/ minute = ???

thanks!!!!!!

hope this helps!!! ?

Specializes in Gerontological, cardiac, med-surg, peds. Has 16 years experience. 105 Articles; 5,349 Posts

minnielynn said:
thank you very much for your reponse!!! as you can see i have spent all day studying for my math final in addition to chem, psych and english. by the time this week is over i will have my eyes stuck behind my head but i understand this is the most important class (right now)

here is another one.......sorry to be a pain in the a--.

magnesium sulfate 4 g iv push, loading dose vial reads 25%. follow with 250 ml d/5/w with one vial of 25% magnesium sulfate, infuse at a rate of 1 gram per hour

don't see that information recorded anwhere in the question???

b. calculate the flow rate in millilters per hour for the d/5/w infusion

the 250 ml d5w has one vial of 25% mag sulfate, which is 4 grams.

250 ml/ 4 g x 1 g/ hr =

250/4 = 62.5 ml/ hr

thanks,

lynn

Hope this helps!

8 Posts

i am having trouble converting between systems of measurement, i am trying to teach myself the conversion factor method as well as the ratio proportion method but this problem is giving me a bit of a problem the problem is ---3g=gr_____ help!

Specializes in NICU. 134 Posts

Not sure if this will make sense but this is how I would calculate it:

1 gram = 1000 mg therefore 3 grams = 3000 mg

gr 1 = 60 mg

(3000/60) = 50

So the answer would be 3 g = gr 50

Anyone feel free to correct me if I am wrong or if there is a better way of explaining it.

Specializes in LTC. Has 4 years experience. 512 Posts

1 g = 15 gr

so

3g = 45gr

Specializes in LTC. Has 4 years experience. 512 Posts

To do proportion it would be 1g/15gr : 3g/xgr and cross multiply

1x=(3x15) 45 then divide by 1, 1 goes into 1 one time and 1 goes into 45 fortyfive times. Wa la your answer 45!

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