Dosage Calculation Question, Please help me : (

[Laura77598]

Hi allnurses,

I have a dosage Calculation question I need help on (ASAP) I have a test tomorrow,yeah I know, no pressure, huh?

Anyway this is an adjusted flow rate question.

Personally I think there is not enough info, but my instructor insists that this is worked correctly. Here it goes.

There are 450 mL in an IV bag. The bag is running at 150 mL/hr.

The bag was started at 10:00 a.m.

At 11:00 a.m. there are 400 mL left in the bag.

To what should you set the flow rate?

This is how the teacher worked the problem, and I don't understand how she got what she got. I don't understand the process, so if someone could approach each step and tell me why she did what she did, I would really appreciate your help!

450 mL = 3 hr

150 ml/hr

11:00 a.m. Why did we do this? How is this significant?

+ 3:00 hrs

2:00 p.m.

Then she said the new total infusion time is 2 hours.

and the new volume to be infused is 400 mL.

(Now I get the 400 mL, but why is the new infusion time 2 hrs? I thought it would be

1 hour since 11:00

-10:00

1:00 1 hour

can someone explain to me why the problem works this way?

Thanks,

Laura

Then:

mL = 400 mL = 200 mL/hr

hr 2 hr

[Cherry2000]

My take:

There is a total of 450 ml running at 150 ml/hr...so that would give you your time frame...of 3 hrs. (450/150)

So if it started at 10 am....3 hours later would be 1 pm...and that is when the infusion should be completed.

The problem is that only 50 ml were infused in 1 hour (10-11 am) So now you have 400 ml left to infuse and only 2 hr to infuse it in.

So the new infusion rate would be 200 ml/hr.

Hope this helps some.