Flow Rate Calculation Problem

[John--RN]

Hi everyone,

I have managed to get up to chapter 18 of math for meds until I ran into a problem. I don't actuall start school until tuesday so I don't have a teacher to ask yet. I need to figure out the gtt/min for the following question;

An IV of 500 mL is to infuse at 120 mL/hr using a 20 gtt/mL calibrated set. ( pg 281 math for meds 10th edition)

Using the formula Volume X Set Calibration 120 mL X 20 gtt/min

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

Time ( 60 min or less) 60 min

I get a rate of 40 gtt/min. The book shows the answer as 83 gtt/min

What am I doing wrong?

Thanks !

John

[AmyJean]

I did 120mL * 20 gtt/mL / 60 minutes and got 40 gtts/min. This is the way I was taught in clinical math....Not sure where the 83 gtts/min is coming from?

[John--RN]

I don't know either, I am not sure if there is an error in the book since I cannot find an errata sheet from the publisher. Four out of the ten of these questions come out with numbers that seem completly wrong.

[DolceVita, ADN, BSN, RN]

You are correct the answer is 40 gtt/min.

The book is wrong.

[itsmejuli]

Hi everyone,

I have managed to get up to chapter 18 of math for meds until I ran into a problem. I don't actuall start school until tuesday so I don't have a teacher to ask yet. I need to figure out the gtt/min for the following question;

An IV of 500 mL is to infuse at 120 mL/hr using a 20 gtt/mL calibrated set. ( pg 281 math for meds 10th edition)

Using the formula Volume X Set Calibration 120 mL X 20 gtt/min

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

Time ( 60 min or less) 60 min

I get a rate of 40 gtt/min. The book shows the answer as 83 gtt/min

What am I doing wrong?

Thanks !

John

(500ml / 120ml )x 20gtt = 83

You can't always trust the book LOL

But 120 / 60 x 20 = 40 is the correct calculation.

[John--RN]

Thank you for the help everyone!

I thought the book might be wrong, but with my *LIMITED* (less then one week) doing this, I just had no way of being sure.

[K.P.A.]

You're gonna see a lot of this. In real life you're gonna have to be comfortable enough with the math to correct/stop someone who is making a mistake.

[John--RN]

Good point! I guess I expected the text book to be better then real life.

[DolceVita, ADN, BSN, RN]

That particular chapter had a few errors.

[John--RN]

:heartbeat

That particular chapter had a few errors.

I counted 5 of them.....In a row. I am very supprised that for a book on such an important topic they do not maintain an online corrections sheet, they are common on technical books of a much less important nature.

[ToBANurse2010]

I got the same answer 40gtts/min.

[DolceVita, ADN, BSN, RN]

I am sure, if I could be bothered, I could contact the publisher.