Quick IV calc. question

Nursing Students Student Assist

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Any help appreciated because these particular IV questions are the only math that in nursing I seem to struggle with.

So for example: If I have 100 mL of a med that I need to infuse over 20 minutes IV, what would I set the pump at in mL per hour?

I do fine if its 30 minutes because then you just divide by 2 obviously but what would you do for 20 minutes, divided by 0.25?

Specializes in Family Nurse Practitioner.

100 ml.........X ml

_______ x ________ = ??

20 min.......60 min

Specializes in NICU, ICU, PICU, Academia.

20 minutes is 1/3 of an hour

thank you both!

Now, for extra credit, what if it's to be infused over 15 minutes?

10 minutes?

Specializes in Pedi.
Any help appreciated because these particular IV questions are the only math that in nursing I seem to struggle with.

So for example: If I have 100 mL of a med that I need to infuse over 20 minutes IV, what would I set the pump at in mL per hour?

I do fine if its 30 minutes because then you just divide by 2 obviously but what would you do for 20 minutes, divided by 0.25?

You don't divide by 2 if the med is to be infused over 30 minutes. If you divide the volume by 2, you are dividing by 2 hrs. 100/2 = 50. If you are to infuse 100 mL of medication and set the pump at 50 mL/hr, it will take 2 hours to infuse your med.

To calculate the rate over 30 minutes, you divide by 1/2 (30 minutes = 1/2 hr).

To calculate the rate over 15 minutes, you divide by 1/4 (15 minutes = 1/4 hr).

To calculate the rate over 20 minutes, you divide by 1/3 (20 minutes = 1/3 hr). Or, multiply by 3, because dividing by 1/3 is the same as multiplying by 3.

So is the answer set the pump at a rate of 300ml/hr?

Specializes in Pedi.
So is the answer set the pump at a rate of 300ml/hr?

Yes. If you want to infuse 100 mL in 20 minutes, the rate is 300 mL/hr.

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