Help with flow rate question

[LCinTraining]

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.

[morte, LPN, LVN]

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

[iluvivt, BSN, RN]

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

[AZMOMO2]

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

[LCinTraining]

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.

[Esme12, ASN, BSN, RN]

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/

[metal_m0nk, BSN, RN]

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.

[LCinTraining]

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!