Med Math Problem

[Johaanas]

Hi Guys,

My classmates and I are trying to do our med math problems and compare answers and we keep getting different answers eeekkk!! Can someone please let me know if I'm doing this correctly? Thank you in advnace!!

"Doctor orders D5 0.25 NS for a 40 kg pt.; use the pediatric fluid maintenance 4:2:1 rule to calculate daily need and then apply hourly rate using the tubing sets below.

- 4 ml/kg/hr for the first 10 kg

- 2 ml/kg/hr for 10-20 kg

- 1 ml/kg/hr for every kg over 20 kg

What is the total daily need:

What is the hourly rate:

So, this is what I did ..

10kg x 4 ml/kg/hr = 40 ml/hr

10 kg x 2 ml/kg/hr = 20 ml/hr

20 kg x 1 ml/kg/hr = 20 ml/hr

So, hourly rate would be 80 ml/hr, correct?

Therefore, total daily need would be 80ml/hr x 24 hr/day = 1920ml/day.

If not, can someone please help me. ?

[JKL33]

3 hours ago, Johaanas said:

So, hourly rate would be 80 ml/hr, correct?

Therefore, total daily need would be 80ml/hr x 24 hr/day = 1920ml/day.

Correct.

3 hours ago, Johaanas said:

- 4 ml/kg/hr for the first 10 kg

- 2 ml/kg/hr for 10-20 kg

- 1 ml/kg/hr for every kg over 20 kg

If this is how all of you are writing it out, though, I can see why there is confusion especially at the second step: Someone may read that and think, "well there are another 20kg to account for (if the child's weight is 40kg), so step 2 would be 2*20 = 40. That misunderstanding gets you a total of 100ml/hr. Probably better to think of it as "4 for each kg of the first 10kg + 2 for each kg of the second 10kg..." and understand that the max you can add at step 2 will always be 20.

Not sure if that's where your classmates are going wrong, but it's possible.

Personally I think this is simpler overall.

[Johaanas]

Thank you so much for your help!!

We were all getting really different answers .. for some reason a couple of my classmates were getting 80 ml/day so then they were dividing it by 24 hours giving them a really small number. I think it was a simple mistake of units. Thank you so much for clarifying.

[Nunya, BSN]

On 8/18/2019 at 11:33 PM, Johaanas said:

Thank you so much for your help!!

We were all getting really different answers .. for some reason a couple of my classmates were getting 80 ml/day so then they were dividing it by 24 hours giving them a really small number. I think it was a simple mistake of units. Thank you so much for clarifying.

For those classmates getting 80 ml/day, to help them reason it out tell them that's less than 3 ounces. A 40kg kid is what 8, 10 years old? Does that sound right?