Need Help With A Math Problem

[blynn9173]

I am studying for my med surg final and there is going to be math on it. They gave us example of what to expect. I have worked all of them out except this one problem. I cannot figure out the right answer. The problem is:

A patient is ordered to receive Ampicillin 10m/kg/day. The Ancef is provided as 1 gram in 100 ml. The patient weighs 88 lbs. How many ML would you give this patient for one 8-hour dose?

I know you covert lbs to kg and that is 40. I took 40/100 and got .4 and that is the wrong answer.

Any help would be appreciated. Thanks.

[brighella]

is it 10mL/kg/day, or is it 10mg/kg/day. Makes a big difference...

[morte, LPN, LVN]

you need wt in kg x 10mg divided by 3......then figure out how much of that 100 ml bag would be required to meet that...

[EDRN-2010]

I am studying for my med surg final and there is going to be math on it. They gave us example of what to expect. I have worked all of them out except this one problem. I cannot figure out the right answer. The problem is:

A patient is ordered to receive Ampicillin 10m/kg/day. The Ancef is provided as 1 gram in 100 ml. The patient weighs 88 lbs. How many ML would you give this patient for one 8-hour dose?

I know you covert lbs to kg and that is 40. I took 40/100 and got .4 and that is the wrong answer.

Any help would be appreciated. Thanks.

I use dimensional analysis:

ml= 100 ml.....10mg........1gram.....1kg.....88lbs.....1day

dose 1 gram....1kg/day....1000mg...2.2lbs..............4 doses

answer: 100ml/dose

or in other terms:

(you are giving 10 mg for each kg and this pt weighs 40 kg, so 400 mg per day and the med is given every 8 hrs so that is 4 times a day so divide 400 by 4=100)

[GeneralJinjur]

(you are giving 10 mg for each kg and this pt weighs 40 kg, so 400 mg per day and the med is given every 8 hrs so that is 4 times a day so divide 400 by 4=100)

Except that 24 divided by 8=3 doses per day, this is one way to do the problem. I like dimensional analysis, but sometimes I get lost in all the cancelling, so I do it piece by piece. I'm going to assume you meant 10mg/kg/day

You already worked out the pounds to kg conversion, so

10 mg times 40 kg = 400 mg/day

400 over X= 1000 (the gram in mg) over 100 mL of fluid. Cross multiply and X=40 mL for the daily dose.

Divide 40mL by 3 to determine the dose given Q8H, which = 13.33333. Round the answer to whatever decimal place the question asks and you're all set.

[EDRN-2010]

Crap, guess my flu symptoms are showing, I thought when I edited this I clicked save but obviously I didn't sorry! 3 doses per day not 4. I hate being sick

I use dimensional analysis:

ml= 100 ml.....10mg........1gram.....1kg.....88lbs.....1day

dose 1 gram....1kg/day....1000mg...2.2lbs..............3 doses

answer: 13.3ml/dose

[melmarie23, MSN, RN]

88/2.2=40kg (to get the weight into kgs)

40kg*10=400mg (to determine the dose needed, 10mg/kg)

400mg=.4g

.4mg/xmL=1mg/100mL (I cross multiply to figure out...its what makes the most sense to me

x=40mL total for the day. Now divide that by 3 (24hrs/8)

40/3=13.33ml q8h. Depending on what you are instructed to round to, approximately 13mLs is your answer.