# Help with flow rate question

Published

I've done this problem ten different ways and keep coming up with 5.5 drops/min, but the answer is 17 gtts/min when I check my answer with the answer code. Any help is appreciated...The order is for D5W at 100 mL/hr. The drop factor is 10 gtts/mL. Calculate the flow rate in drops/minute.I've tried various dimensional analysis set ups, but 5.5 is what I get. I'm starting to think I'm missing a conversion factor that I can't seem to remember or something.

7,015 Posts

17 is correct, what are YOU doing to get 5.5? show us your work, and we can better help.

2,773 Posts

Specializes in Infusion Nursing, Home Health Infusion. Has 32 years experience.

Try this formula.......volume to be infused X the drip factor

-------------------------------------------------

time in min

so get your top value and divide it by the time in min

here is a fast way to get the answer for tests ..divide the cc per hr by either 6 (drip factor of 10) 5 (for a drip factor of 12).....4 (for a drip factor of 15) and 3 (for a drip factor of 20)..... so in your case 100 divided by 6 is egual to 16.66 and round it up to 17

So now work it out both ways and practice

1,194 Posts

Specializes in Cardiac Care.

10(drip factor) X 100(ml) / 60 (minutes in an hour) = 16.66 = 17 gtts/min

308 Posts

Let me rewrite it and get back to you after my nap. I have to work a 12 overnight so it's nap time. I erased my work so now I don't remember, but I'll rework it before looking at the other suggestions so you can see what I'm doing.

4 Articles; 20,908 Posts

Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma. Has 43 years experience.

Formula:

[TABLE=class: formula]

[TR]

[TD]

[TABLE=class: fraction]

[TR]

[TD=class: numerator]Volume (mL)

[/TD]

[/TR]

[TR]

[TD=class: denominator]Time (min)

[/TD]

[/TR]

[/TABLE]

[/TD]

[TD] x Drop Factor (gtts/mL) = Y (Flow Rate in gtts/min)

[/TD]

[/TR]

[/TABLE]

Example: Calculate the IV flow rate for 1200 mLof NS to be infused in 6 hours. The infusion set is calibrated for a drop factor of 15 gtts/mL.[TABLE=class: example]

[TR]

[TD]

[TABLE=class: fraction]

[TR]

[TD=class: numerator]Volume (mL)

[/TD]

[/TR]

[TR]

[TD=class: denominator]Time (min)

[/TD]

[/TR]

[/TABLE]

[/TD]

[TD] x Drop Factor (gtts/mL) = Y (Flow Rate in gtts/min)

[/TD]

[/TR]

[/TABLE]

Convert 6 hours to minutes.

• min ← hr ( x by 60 )
• 6 hr x 60 = 360 min

[TABLE=class: example]

[TR]

[TD]

[TABLE=class: fraction]

[TR]

[TD=class: numerator]1200 mL

[/TD]

[/TR]

[TR]

[TD=class: denominator]360 min

[/TD]

[/TR]

[/TABLE]

[/TD]

[TD] x 15 gtts/mL = 50 gtts/min

[/TD]

[/TR]

[/TABLE]

Example: Calculate the IV flow rate for 200 mLof 0.9% NaCl IV over 120 minutes. Infusion set has drop factor of 20 gtts/mL.[TABLE=class: example]

[TR]

[TD]

[TABLE=class: fraction]

[TR]

[TD=class: numerator]Volume (mL)

[/TD]

[/TR]

[TR]

[TD=class: denominator]Time (min)

[/TD]

[/TR]

[/TABLE]

[/TD]

[TD] x Drop Factor (gtts/mL) = Y (Flow Rate in gtts/min)

[/TD]

[/TR]

[/TABLE]

[TABLE=class: example]

[TR]

[TD]

[TABLE=class: fraction]

[TR]

[TD=class: numerator]200 mL

[/TD]

[/TR]

[TR]

[TD=class: denominator]120 min

[/TD]

[/TR]

[/TABLE]

[/TD]

[TD] x 20 gtts/mL = 33 gtts/min

[/TD]

[/TR]

[/TABLE]

Go here for more help....it's a great site. This website provides a dosage calculations tutorial, complete with explanations and examples, to help nursing students prepare for a medication exam.

http://www.dosagehelp.com/

920 Posts

Specializes in ICU.

16.66666666666666666666666666666666666666666666666666 is what I came up with.

Pretty easy.

Since you're looking for a per minute rate and the order is per hour, first find how many mL are to be administered per minute.

100ml/hr divided by 60 minutes = 1.66666666666666666mL/min

Then multiply your drip factor (drops/mL) by the number of mL/min.

(10gtt/mL) x (1.66666666666mL/min) = 16.66666666666666666

The mL's cancel out and you're left with gtt/min.

308 Posts

I figured out what I was doing wrong. I kep trying to convert gtts to actual drops and was using an example of 20 drops/mL that was given in lecture.Gtts IS the drop. I got it now. Thanks!

• ## Care Plans Guide

Create well-written care plans that meets your patient's health goals.