# Practice Problem Zosyn 4.5 g in 100 mL?

Posted
by RN_TOBE

Zosyn 4.5 g in 100 mL NS IVPB in 30 min BID

what is the rate in ml/hr?

maybe it *ml/hr = 4.5/100*60

help..........

Specializes in NICU. Has 7 years experience. 4,040 Posts

the drug and amount is a distractor. They are asking about fluid only. If you have 100 ml and you want it to finish in 1/2 hr. What rate do you need it to run?

A) 50ml/ hr

B) 100ml/hr

C) 200ml/hr

D) wide open and chart it in 30 minutes.

Specializes in ICU, PCU. Has 9 years experience. 458 Posts

I was taught to use dimensional analysis. Start by identifying the units you want and plug in known information, while making sure the undesired units cancel out:

? mL/hr = (100mL/30mins)*(60mins/1hr)

The 100mL/30mins term is the rate of administration which was given in the problem.

The 60mins/1hr term is the conversion factor for minutes to hours.

You'll notice that the "minutes" unit cancels out as it appears I'm both the numerator and denominator of the function.

Has 14 years experience. 2,103 Posts

What do the data/numbers in the question represent? You need to understand what they are, not just try to fit all the available data into an equation of some sort. You need to grasp why one number is multiplied or divided by another number. You will often be given information that isn’t necessary to figure out the correct answer to the question. Don’t get distracted by that information. What do the numbers represent?

Imagine that you were to put 4,5 grams of sugar into a glass containing 100 ml of water and then give it a quick stir.. How much water do you have in your glass after the sugar is dissolved? It’s still 100 ml.

Now you’re told to drink (well, sip really) this “sugarwater” during a time period of 30 minutes. Assuming that you drink the water at a constant rate, how many ml would you have to drink every minute in order to be done in thirty minutes?

Now you’ve finished your water in half an hour and you know how many ml per minute you’ve drunk. Now you just need to convert ml/min to ml/hr.

Good luck!

Specializes in SICU, trauma, neuro. Has 16 years experience. 5,047 Posts

Yes, the drug and dosage is important when you're checking your 7 rights, but you're just figuring how fast to run 100 ml to infuse it in 30 minutes. 100 ml/0.5 hr=x ml/1 hr

34 Posts

Thanks you all....

2 Articles; 5,114 Posts

Medication math isn't really formulae, it's basic algebra, with success in "solve for X" depending on your ability to discern what "X" is in a word problem. :) We see people here all the time that can't read a problem, see which data points are needed and which are distractions/extraneous, and they cram all of it into a big dimensional analysis thing, and come up with a nonsensical answer, and then get flustered and confused. The people who write the questions know that, so they put in distractors (wrong answer choices) that will result if the wrong or extraneous data are put into a formula, so they catch the people who rely on rote/slavish dependence on a given formula.

Think, people, just think. What are they asking you? If the question is asking for a cc-per-hour answer, it doesn't matter whether there's 4.5 gm, 45 mcg, or 450 mg in the volume you have to give. Give 100cc in half an hour-- you should be able to do that in your head.

2 Articles; 5,114 Posts

D) wide open and chart it in 30 minutes.

:beer:

Specializes in Gerontology RN-BC and FNP MSN student. Has 22 years experience. 739 Posts

Haha Don!

Specializes in NICU. Has 7 years experience. 4,040 Posts

I do it all the time with Potassium. Run 100 mL wide open and then check in on the patient in 30 minutes. Never could understand why the cardiac monitor has a nice normal sinus rhythm, then gets all squiggly when I check on the patient in 30 min. :no:

Specializes in Pedi. Has 15 years experience. 1 Article; 7,349 Posts

Half an hour is, well, HALF an hour. So if you give 100 mL in thirty minutes, how many mL would you give in twice that time? That's your rate in mL/hr.

Specializes in Emergency. Has 21 years experience. 2,842 Posts

I do it all the time with Potassium. Run 100 mL wide open and then check in on the patient in 30 minutes. Never could understand why the cardiac monitor has a nice normal sinus rhythm' date=' then gets all squiggly when I check on the patient in 30 min. :no:[/quote']

And you run it undiluted through a 22 in the hand.... :^)

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