Need Dimensional Analysis Help!!

Nursing Students Student Assist

Published

Please help....I cannot figure out how to do this one. The answer is 3 cc. Need DA method. Thanks!!

A Nitroglycerin drip is ordered for your patient to control his chest pain. The concdentration is 100 mg in 250 cc D5W. Order is to begin the infusion at 20 mcg/min. What is the rate you would begin the infusion on the infusion pump?

Up Vote Up Vote ×
Specializes in Wound Care, LTC, Sub-Acute, Vents.
please help....i cannot figure out how to do this one. the answer is 3 cc. need da method. thanks!!

a nitroglycerin drip is ordered for your patient to control his chest pain. the concdentration is 100 mg in 250 cc d5w. order is to begin the infusion at 20 mcg/min. what is the rate you would begin the infusion on the infusion pump?

i am not sure if this is correct but here it goes:

part 1:

convert 100mg to 100,000mcg then divide by the 250cc d5w

= 100,000mcg/250cc

=400mcg/cc

part 2:

multiply the infusion rate with 60 because you want the rate to be in per hour not per min

20mcg * 60

= 1200mcg/hr

now, divide part 2 with part 1 and you get

1200mcg/400mcg

=3 cc/hr

and by the way, we don't use cc any more. it's ml.

Up Vote Up Vote ×
Specializes in Urgent Care NP, Emergency Nursing, Camp Nursing.

Math looks right to me, though I wouldn't have done it all for the OP.

Also, just because something is on the JCHAO no-no list doesn't mean people don't use it all the time. :banghead:

Up Vote Up Vote ×
Specializes in Cardiac, Derm, OB.
please help....i cannot figure out how to do this one. the answer is 3 cc. need da method. thanks!!

a nitroglycerin drip is ordered for your patient to control his chest pain. the concdentration is 100 mg in 250 cc d5w. order is to begin the infusion at 20 mcg/min. what is the rate you would begin the infusion on the infusion pump?

available: 100mg/250cc (cc=ml)

order: 20mcg/min

question: ?ml/hr

da: ml/hr=250ml/100mg x 1mg/1000mcg x 20mcg/min x 60min/1hr = 300,000/100,000 = 3ml/hr

if you will pull the info out first it will help you set up your da problem. identify available, order, what question/looking for and then set problem and do conversions.

Up Vote Up Vote ×

Is the "available" factor always first vs. "what's ordered"? I'm trying to teach myself DA before January.

Up Vote Up Vote ×
Specializes in Cardiac, Derm, OB.
is the "available" factor always first vs. "what's ordered"? i'm trying to teach myself da before january.

no particular order just pull out the info to set up the problems.

order "dimensional analysis" by curren, (old edition, 2nd/3rd few bucks) and it walks you through step by step and gives lots of practice questions!. on amazon, looks like they start around $3.88 + ship so less than $8.

makes it super duper clear.

Up Vote Up Vote ×

OK, I will.

Can you use DA for all calculations? Is it preferred over formula, ratio/proportion? I only want to learn one method and not get confused.

Thanks!

Up Vote Up Vote ×
Specializes in Cardiac, Derm, OB.
OK, I will.

Can you use DA for all calculations? Is it preferred over formula, ratio/proportion? I only want to learn one method and not get confused.

Thanks!

I use DA for all calculations. It is REQUIRED at our school. If you cannot show it DA then it is wrong even if the answer is right. Thus, luckily this method for me has "clicked" and makes sense to me. You can try different methods if you like but in the end it is which you like and depending on your school.

Up Vote Up Vote ×
Specializes in Urgent Care NP, Emergency Nursing, Camp Nursing.

Dimensional analysis is also what you were taught in HS Chemistry and in Gen Chem I - which is why I'm constantly amazed at the people who try to remember all sorts of odd formulas for dosing and/or can't do dimensional analysis. Everyone has to have seen it at some point before they start on their nursing coursework, unless one's school has really weird prereqs.

Up Vote Up Vote ×
+ Add a Comment