Help with IV cauculation please!!

morte, LPN, LVN · Jan 26, 2009

vanco is supplied as a dry powder....must be disolved, that is what the 4.5 ml is for....then it is put into the 250 ml bag...= 265. divide by 2 =133ml per hour....divide by 60 = ml per minute, then multiply by 10 (drop factor)=flow rate in drops per minute

the drug dose is given in the problem, so i dont understand that part of the question.....your giving 1.5grams..the volume is indeed 15 ml.........

good luck

Daytonite, BSN, RN · Jan 26, 2009

give vancomycin 1.5g q12h

available: vancomycin 500mg, add 4.5ml to each vial to yield 5 ml/vial

set and solution: 250 ml bag of d5w and a set with a 10 gtt/ml drop factor

instruction: infuse over 2 hr

a. drug dose?

b. flow rate?

what does "add 4.5ml to each vial to yield 5ml/vial" mean?

the question is telling you that vancomycin 500 mg comes in a vial of powder. in order to add it to any bag of iv fluid it must be changed into a liquid. to do that, the directions are "

add 4.5ml to each vial to yield 5 ml/vial

". so, you must figure out what solution you can add to this powder. you would look at a drug reference. usually, it is sterile bacteriostatic water or sterile normal saline. these come in 20 ml and 30 ml vials that are stock supply on nursing units. you would draw 4.5 ml from one of these into a syringe and add it to the vial of vancomycin powder, shake it, and allow the mixture to dissolve into solution. the result will be a 500 mg solution of vancomycin that is

500 mg (of vancomycin)/5 ml

.

i found some equations online.. but i wasn't sure if they are the correct one to use or how to apply it.

i have always used this formula for calculating the dose to give:

dose desired

divided by the

dose on hand

=

dose to give

.

these three terms can be manipulated in equations as long as any two of them are known in order to give you the third term.

dose desired

: 1.5 grams

dose on hand

: 500 mg/5 ml

1.5 gram

(dose desired)

/500 mg

(dose on hand)

x 1000 mg/1 gram

(conversion factor)

x 5 ml/1

(amount the dose on hand comes in)

=

15 ml

(dose to give)

to calcuate flow rate. . .

amount to give

: 250 ml (of the d5w) + 15 ml (of the vancomycin), or 265 ml over 2 hours

drop factor of iv tubing

: 10 gtts/ml

265 ml/2 hours

(amount and time to give)

x 10 gtts/ml

(drop factor of iv tubing)

x 1 hour/60 minutes

(conversion factor)

= 22.08333 gtts/minute

, round off to

22 drops/minute

(flow rate) drops must be given as whole numbers. [

note:

you will get 20 gtts/minute if you do not take into account the 15 ml of vancomycin that are added to the d5w]

there are drug calculation tutorials listed on post #2 of this sticky thread:

https://allnurses.com/general-nursing-student/nursing-math-thread-264395.html - the nursing math thread