Published Nov 18, 2010
TJG21
5 Posts
How to work this one out? If you are good at math I could use your help on this homework problem.
infuse 500 ml of lactated ringers over 4 hours / tubing that has a drop factor of 15 gtt/ml. What is the infusion rate in gtt/min?
itsmejuli
2,188 Posts
what don't you understand?
vsledge
1 Post
4hrs= 240 mins
500ml/240mins x 15= 31.25 or 31 gtt/min
Esme12, ASN, BSN, RN
20,908 Posts
I usually do not mind helping but.........it is obvious you have a computer so....
http://tinyurl.com/2dmt36z or
google it.........DosageHelp.com - Helping Nursing Students Learn Dosage Calculations
thestrella
49 Posts
easy step
500 ml / 4 hrs = 125
then memorize this for drop factor = 60 gtts = 1
20 = 3
15 = 4
12 =5
10 = 6
since ur drop factor is 15
the next solution is 125 / 4 = 31.25 = 31gtts/min
johnnyDoGood
121 Posts
i come up with 31.25 gtt/min
take 500ml and multiply by 15 gtt then divide it all over 240 minutes. because 4 hours is 240 minutes.
wow you made that so easy thanks a lot! I don't know why I had trouble figuring this out but got it now, tired I guess.
TJ
I have been using google but just wanted help getting on track with one math problem, I don't appreciate you being so condescending
CharlieT
240 Posts
I do this a little different than most, but we all get the same answer.
500ml x 15gtt = 7500 total drops to be infused
7500 drops divided by 4 hours = 1875 drops per hour
1875 divided by 60 (minutes in one hour) = 31.25, round to 31 drops per min.
OK well as long as it works
I prefer dimensional analysis and worked it out like this:
125 mL X 1 Hr X 15gtt =
------------------------ 31 gtt/min I canceled out the mL's and Hr's and was left with gtt/min
1 hr 60 min 1 mL
RoyalNurse2010
64 Posts
Always remember to round when doing gtts/min because you can not give a point of a drop.
carolmaccas66, BSN, RN
2,212 Posts
I'm not giving you the answer. U need to GO BACK AND LEARN UR FORMULAS. Getting answers off of here will not help u understand the maths involved.
The formula for this is:
500 divided by 4 hours, x 15 divided by 60.
500 x 15
4 60
You need to work out WHY this is the correct formula for this problem as well, otherwise trust me u will be struggling in the future, and could possibly make serious med errors. If u don't understand one calculation, u won't understand all the others either.
This one is in drops per minute, but u also need to know how to work out mls per hour as well, & not get them confused.