The Nursing Math Thread

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A member pm'd me the following question highlighted below. We created this thread for you guys to talk about math, solve math problems, and post math websites that you have found helpful.

I was wondering, is there a sticky or a special site that can be coordinated for "math sufferers". Perhaps, beginning calculations or shall i say the basics..simple to complex...step by step on how to calculate. I'm a visual learner, numbers and I don't work well. I am trying, but I've got a block!

Specializes in med/surg, telemetry, IV therapy, mgmt.

I'm feeling quite well since my chemo has been over for several months. However, I am having surgery again next week. It will slow my typing down a bit is all. Pull a piggyback bag the next time you are in lab or clinicals and look at it and a couple of syringes so you can make some correlations here.

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On our exams it states to round off to 2 decimal places WHEN NECESSARY,lol And thats where the confusion lays with this problem.

When you are doing drip factors you will do this...you can't give part of a drop!:chuckle

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Specializes in med/surg, telemetry, IV therapy, mgmt.
When you are doing drip factors you will do this...you can't give part of a drop!:chuckle

I wouldn't. :eek:

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I'm pretty sure daytonite could do a 0.34 of a drip if she really wanted too!! You hear those Cuck Norris Fables, such as "His tears cures cancer, but her never cries" or" chuck norris can sneeze with his eyes open" Well Daytonite can with her eyes closed an squeeze out a .34 of a drop!! lol She is that good!!! We students owe her a lot!! I bow down!!!

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This formula helps with simple calculations. Say 25 mg of a drug is ordered and on hand is a vial containing 50mg/2ml. How many mL do you give.

Set it up like this

50mg x 25mg = 50 x= 50 x=1 mL

2 mL xml 50 50

Keep mg across from one another on the top, and mL across from one another on the bottom. Then do simple cross multiplying, divide by the number next to x and this will give you your mL.

To calculate gtts/min, you have to know your drop factor which is either 20 gtt/min (standard) or 60gtts/min for a microdrip. Here is the fromula i use

total volume (ml) x drop factor/ 1 min = gtt/min

minutes (*not hrs)

so lets say. 250ml x 20gtt/1min= 5000= 83.3=83 gtts/min

60 min 60

Hope this helps.

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The math is one of my weak areas, as well...I found the following websites helpful. And you can even start reviewing from basic algebra and work your way forward...there arre also quizzes to test yourself...

www.accd.edu/SAC/NURSING/math/default.html

www.alysion.org/dimensionalanalysis.htm

Hope they are helpful!!

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Specializes in med/surg, telemetry, IV therapy, mgmt.
The math is one of my weak areas, as well...I found the following websites helpful. And you can even start reviewing from basic algebra and work your way forward...there arre also quizzes to test yourself...

www.accd.edu/SAC/NURSING/math/default.html

www.alysion.org/dimensionalanalysis.htm

Hope they are helpful!!

These were already listed on post #3 of this thread.

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oops, I made a mistake

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Specializes in Observation Unit, ACLS, BLS.

Hi I have a question I would appreciate any help I have a dosage and calculations exam this friday and this practice question is giving me problems it goes. By the way its a reconstitution problem. Ordered: Pen G 1,000,000 Units IM q 6h

Available the label says 5,000,000 units per vial Pen G for injection USP

preparation for solution: Add 23ml, 18ml, 8ml, or 3ml diluent to provide 200,000 u, 250,000 u, 500,000 u, or 1,000,000 u per ml respectively.

The answers my school gave on the practice test is Add 3ml diluent and administer 1ml per dose or 8ml diluent and administer 2ml.

Please can anyone break this down for me.

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1,000,000u: 1ml :: 1,000,000: x ml

1,000,000x= 1,000,000

x=1ml

500,000u: 1ml :: 1,000,000: x ml

500,000x= 1,000,000

x=2ml

Does this help? It is Ratio and Proportion. I always use this unless it is IV drip rates then I use DA. Try to eliminate all the extra data when solving. You don't really need to worry about the diluent at first because the problem breaks it down for you, you just need to solve for you dose desired per ml.

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Specializes in med/surg, telemetry, IV therapy, mgmt.
hi i have a question i would appreciate any help i have a dosage and calculations exam this friday and this practice question is giving me problems it goes. by the way its a reconstitution problem. ordered: pen g 1,000,000 units im q 6h

available: the label says 5,000,000 units per vial pen g for injection usp preparation for solution: add 23ml, 18ml, 8ml, or 3ml diluent to provide 200,000 u, 250,000 u, 500,000 u, or 1,000,000 u per ml respectively.

the answers my school gave on the practice test is add 3ml diluent and administer 1ml per dose or 8ml diluent and administer 2ml.

please can anyone break this down for me.

draw pictures for yourself if it will help. there are actually 4 different problems here. i like to use the formula dose desired divided by the dose on hand multiplied by the amount that the dose on hand comes in gives you the amount to give.

if you mix the 5,000,000 units with 23 ml of diluent you will have a solution of 200,000 units/ml (information given in the problem). ordered: pen g 1,000,000 units im q 6h. how much pen g will you give?

1,000,000 units
(dose desired)/
200,000 units
(dose on hand)
x 1 ml
(amount the dose on hand comes in)
=
5 ml
(amount to give)

if you mix the 5,000,000 units with 18 ml of diluent you will have a solution of 250,000 units/ml (information given in the problem). ordered: pen g 1,000,000 units im q 6h. how much pen g will you give?

1,000,000 units
(dose desired)/
250,000 units
(dose on hand)
x 1 ml
(amount the dose on hand comes in)
=
4 ml
(amount to give)

if you mix the 5,000,000 units with 8 ml of diluent you will have a solution of 500,000 units/ml (information given in the problem). ordered: pen g 1,000,000 units im q 6h. how much pen g will you give?

1,000,000 units
(dose desired)/
500,000 units
(dose on hand)
x 1 ml
(amount the dose on hand comes in)
=
2 ml
(amount to give)

if you mix the 5,000,000 units with 3 ml of diluent you will have a solution of 1,000,000 units/ml (information given in the problem). ordered: pen g 1,000,000 units im q 6h. how much pen g will you give?

1,000,000 units
(dose desired)/
1,000,000 units
(dose on hand)
x 1 ml
(amount the dose on hand comes in)
=
1 ml
(amount to give)

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Hi I have a question I would appreciate any help I have a dosage and calculations exam this friday and this practice question is giving me problems it goes. By the way its a reconstitution problem. Ordered: Pen G 1,000,000 Units IM q 6h

Available the label says 5,000,000 units per vial Pen G for injection USP

preparation for solution: Add 23ml, 18ml, 8ml, or 3ml diluent to provide 200,000 u, 250,000 u, 500,000 u, or 1,000,000 u per ml respectively.

The answers my school gave on the practice test is Add 3ml diluent and administer 1ml per dose or 8ml diluent and administer 2ml.

Please can anyone break this down for me.

The more diluent you add, the less concentrated the dose will be meaning adding 3ml gives the solution the strength of 1,000,00u/mL vs. adding 23 mL gives the solution the strength of 200,000 u/mL. Since you need to give 1,000,000 units, you will add 3 mL to give the dose you draw up into the syringe 1,000,000 u/mL .

NOTE: always add the amount of diluent that is closest to the dose that has been ordered to give. For instance, if the doc ordered 100,000 u you would add 23 mL making the strength 200,000u/ml and you would draw 0.5 mL into the syringe. By doing so you have 100,000 u of PenG to give. Hope this helps. Another example would be the doc has ordered 225,000 u which seems like theres not a right answer since this fall right between 200,000 and 250,000 but, always choose the strength that will require the least amount of mL's to draw up which in this case would be the 250,000. PenG hurts going in IM so its a matter of pt. comfort. :nurse:

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