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Not familiar with this type of Dosage Calc. problem...PLEASE HELP ME


Hello allnurses,

I've been sooo busy trying to teach myself Dosage Calculations with my book before classes start, and I have been doing really well so far! But now and again I find a problem that isn't explained well and the book doesn't offer an example of the problem with the problem solved. Can somebody on here please help me with this one. I would really appreciate it.

Thank you wonderful people for all your help!

Here it is:

An adult is receiving 4 gtt/min of a solution that contains 8 mg in 250 mL D5W.

Is this within the normal range of 2-4 mcg/min?

mcg/min infusing = Normal range?

I just really don't have enough practice to know how to set this one up using DA.

Thanks again,


CritterLover, BSN, RN

Specializes in ER, ICU, Infusion, peds, informatics. Has 22 years experience.

first, you need to know what the drop factor (drops/cc) is on your tubing.

macro tubing is usually 10 or 15 drops/cc.

micro tubing is usually 60 drops/cc.

Daytonite, BSN, RN

Specializes in med/surg, telemetry, IV therapy, mgmt. Has 40 years experience.

the problem is basically asking you to convert 4 gtts/min of a solution of 8 mg in 250 ml to x mcg/min. first, you have to determine how many mg/min you are actually giving this patient. the problem is missing information and should have told you what kind of iv tubing was being used. based on the kind of tubing being used you would know how many drops there would be in one ml of fluid. 1 ml = 16 gtts (minims) in standard iv tubing, or 60 gtts in microdrip tubing. also, you need to know that 1 mg = 1000 mcg.

8 mg/250 ml x 4 gtts/minute x 1 ml/16 gtts
(conversion factor for using standard iv tubing)
x 1000 mcg/1 mg
(conversion factor)
= 8 mcg/minute
(dose patient is receiving).
this would
be within the normal dose range.

however, it's more likely that microdrip tubing is being used

8 mg/250 ml x 4 gtts/minute x 1 ml/60 gtts
(conversion factor for using microdrip iv tubing)
x 1000 mcg/1 mg
(conversion factor)
= 2 mcg/minute
(rounded off, dose patient is receiving).
be within the normal dose range.

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