My fear of Pediatric rotation

Jules A, MSN · Feb 28, 2009

newtress said:
Lasix 10 mg IV stat is ordered for child weighing 22 lb. The recommended initial dose is 1 mg/kg. Is the dosage ordered safe?

Relax, these are the exact same problems you have been doing with an extra step or two. First I'd figure out how many kgs a 22 lb child weighs. Multiple the weight in kgs by the dose (1mg in this case) per kg. Is that the correct dose?

newtress said:
Amoxicillin 150 mg p.o. q8h is ordered for an infant weighing 23 lb. The maximum daily dosage for an infant is Amox p.o. 20 to 40 mg/kg/day divided q8h.

Again find the weight in kgs. Multiply that by both doses you are given: 20mg and 40 mg. Since the dose is divided q8 that means you have to divide the total by 4 (24 hours in a day/q8h dosing) to get the q8 dose. Is 150mg within that range?

AdobeRN · Feb 28, 2009

This is how I figure these out. It always works.

Convert 22lb to kg. 22/2.2 = 10kg

1mg/kg = 1 x 10 = 10mg

Max dose will be 10mg.

Convert 23lb to kg. 23/2.2 = 10.45kg

20-40mg/kg/day divided Q8. 20 x 10.45 = 209mg 40 x 10.45= 418mg

209mg-418mg/day.

Order dose is 150mg Q8. 150mg x3 doses = 450mg/day. Dose is out of the max daily dose range. You dont need to know how the med comes.

newtress, LPN · Feb 28, 2009

Thank You for giving back! I'll take all advise I can get.

elsabelles · Mar 1, 2009

See the attached picture for the problems.

It's dimensional analysis. This site is wordy, but may be helpful. Or just google it. http://www.alysion.org/dimensional/analysis.htm

Hope it helps!

Multicollinearity, BSN, RN · Mar 1, 2009

While you might not need a textbook for this, it might be helpful to pick one up, and it might ease your mind.

You'll find instruction on various ways of calculating doses for med/surg and all the specialty areas, including peds.

Daytonite, BSN, RN · Mar 1, 2009

we work these kinds of questions on the student forums all the time. on post #2 of this sticky thread on the general nursing student discussion forum is a listing of websites you can go to with free online tutorials and practice problems/answers on doing these:

with children's medications, you often want to check that the dosage ordered is a safe dose before you give the prescribed dose. safe dose information can be found in nursing drug references and it often comes in the prescribing information leaflets that come with these vials of medication.

I work problems using dimensional analysis:

lasix 10 mg iv stat is ordered for child weighing 22 lb. the recommended initial dose is 1 mg/kg. is the dosage ordered safe?

Calculate what the safe dose would be:

1 mg x patient's weight in kg = 1 mg (recommended dose)

x 22 pounds (patients weight)

/2.2 pounds (conversion to kg)

= 10 mg (safe dose)

Next, compare what the doctor has ordered with what the recommended initial safe dose is to determine if it is safe to give:

ordered: 10 mg
safe recommended: 10 mg

Yes, the ordered dose is safe to give.

amoxicillin 150 mg p.o. q8h is ordered for an infant weighing 23 lb. the maximum daily dosage for an infant is amox p.o. 20 to 40 mg/kg/day divided q8h

In setting this up, note that the doctor is ordering the amoxicillin to be given q8h, or 3 times in a 24 hour period. also note that the maximum daily dosage for this same drug is given to you as a daily amount (24 hours) and telling you to divide it into q8h doses.

Calculate what the maximum safe dose would be using what you were given (40 mg/kg/day divided q8h?

40 mg/1 day (maximum safe dose)

x 23 pounds (patient weight)

/2.2 pounds (conversion to kg)

x 1 day/3 doses (conversion to one dose)

= 139.3939, round off to 139 mg/dose

(maximum safe dose).

Next, compare what the doctor has ordered with what the maximum daily dose is to determine if it is safe to give:

ordered: 150 mg q8h
safe maximum: 139 mg q8h

Is the ordered dose safe? No, it isn't. It is over what the maximum daily dose should be. you would not give this medication and would call the physician.

The point of this problem was to double check that the doctor had ordered a safe dose of the amoxicillin for the little patient. that is all. How the med is supplied has nothing to do with the problem. It is easier to understand these when the medications are in front of you and you can see them. These are good old math word problems and they are based in real world situations.

newtress, LPN · Mar 1, 2009

Alas, There is Daytonite! I was hoping I'd see a reply from you. I did swing over to the discussion sticky and found the websites o' plenty. Particularly helpful was the dosage help dot com site. But would like to personally thank Daytonite for the break down of the two examples. I feel much better going into clinical now with my 50! peds dosage calc problems worked and filled in the blanks. :heartbeat :up:

Daytonite, BSN, RN · Mar 1, 2009

i don't usually check the posts on this forum. things are slow this morning on the student forums which is why i came looking over here to see what had been posted here. there are pediatric websites posted on this sticky that you might also find helpful for your peds rotation as well although they don't have med calculations in there: https://allnurses.com/nursing-student-assistance/medical-disease-information-258109.html. the kids health website has a lot of good information in nice easy to read language on all kinds of children's subjects from babies to teens. and many of the websites that are listed have developmental milestones for children on them which is something you usually need to know for peds tests.

dotherightthing · Mar 1, 2009

How much does the kid weigh? That's the first question.

Set it up like this, pretend like you have two boxes on top and two on bottom

2.2 lb. 22 lb

1 kg X is ? many Kg

The set up calculation, 2.2 lb always equals 1 kg. What you know about your calculation is in the top right box. What you want to know is X.

No matter what you're asking, the right and left boxes should be the same, inches, kg, miles, mg., Grams, ml., even time.

Now cross multiple using top right X bottom left. 22. Then divide it by the top left number. 22 divided by 2.2=10. 10 is X and the answer.

Set it up again for the final answer.

1 kg 10 kg

1 mg X=

What you know is that the dose is 1kg to 1mg.

It seems wierd to say 1 kg = 1mg instead of the way you think it, which is 1mg=1kg. But get past that little bit of wierdness and you can use this calculation for cooking, mileage, any medication, heights, anything. Just make sure the X is in the bottom right box and from left to right, it's the same value. At the bottom right you're looking for the same value.

10 kg X 1 mg=10

10 divided by 1 kg = X which is 10 mg, the amount of lasix that you can give your kid.

The next calculation.

2.2 lb 23 lb. (the kid's wt.)

1 kg ? many kgs

multiply bottom left X top right to get 23 and divide it by 2.2, which =10.45 or 10.5 kg. your kid's wt.

You can give Amox. 40 mg per kg max.

10.45 kg X 40 mg/day =418 mg in q 8 h doses

418mg divided by 3= 139.3 rounded down to 139 mg Amoxicillin q 8 hr. The doc ordered too much and you can't give it.

Again, this is sweet and works for any calculation, cups and ounces, any. It really doesn't look right here but if you reply with your email address, (can we do that on this site?) I'll show you what this looks like on paper. It's one of those things that's helpful to see.

UM Review RN, ASN, RN · Mar 1, 2009

Note to posters: please do not post your email on the board or you'll get spammed to death. It's OK to share emails via Private Message. You must have 15 posts and then your PM system will activate.

newtress, LPN · Mar 2, 2009

Wow, Dotherightthing this is a new view into this ped calculation. Sure do appreciate you setting up the calc for the problem. It still amazes me how some folks can glide through these math problems while I feel like it's a painful rectal itch to me! I start peds rotation in the morning. Armed with all the support and replies from the Allnurses community I feel a whole lot better. Seeing my instructor might give me an adverse effect though.