Med Math Flow Rate for IV

[cocostar]

Please help! I am having a hard time figuring out how to get the volume of infusion (mL) for these problems. What confuses me more is when the instruction says to dilute in _ mL. What are we supposed to be diluting the medication in as in what solution?

1. Give amikacin 800 mg IVPB, now

Available: Amikacin 500 mg/2 ml

Set and solution: D₅W 150 ml minibag and a drop factor of 15 gtt/ml set

Instructions: Infuse over 60 min

150 ml/60 min x 15 gtt/ml=37.5 gtt/ml=38 gtt/ml (Why is it 150 mL?)

2. Give nafcillin 250 mg IVPB q4h

Available: Nafcillin 500 mg and 1.8 ml diluent to yield 2 ml

Set and solution: Buretrol with a 60 gtt/ml drop factor and NS (normal saline) 500 ml

Instructions: Dilute in 50 ml and infuse over 30 min

50 ml/30 min x 60 gtt/ml=100 gtt/min (Why 50 mL? What about the 500 mL of NS? What is Buterol doing in this problem and is NS dropping at a rate of 60 gtt/ml too? The set and solution part just confuses me here.)

3. Give tobramycin (Nebcin) 60 mg IVPB q6h

Available: tobramycin (Nebcin) 80 mg/2 ml

Set and solution: 50 ml bag D₅W and a set with a 15 gtt/ml drop factor

Instructions: Dilute with 50 ml and infuse over 30 min

50 ml/30 min x 15 gtt/ml=25 gtt/min (Why 50 ml? Confused here cause there is a 50 ml bag of D5W and it says to dilute with 50 ml.)

4. Give cephradine 1 g IVPB q6h

Available: Cephradine 500 mg, add 4.5 ml diluent to each vial to yield 5 ml/vial

Set and solution: 50 ml bag of D₅W and a set with a 15 gtt/ml drop factor

Instructions: Infuse over 30 min

60 ml/30 min x 15 gtt/ml=30 gtt/min (Why 60 ml? Why is this problem adding the 10 ml of one drug dosage onto the 50 ml to get 60ml? Why didn't we add the drug dosage onto the _mL for the other problems?)

[NICUismylife, ADN, BSN, RN]

What confuses me more is when the instruction says to dilute in _ mL. What are we supposed to be diluting the medication in as in what solution?

In each problem, where it says "set and solution" it tells you the solution. D5W and NS are both solutions commonly used for dilution.

60 ml/30 min x 15 gtt/ml=30 gtt/min (Why 60 ml? Why is this problem adding the 10 ml of one drug dosage onto the 50 ml to get 60ml? Why didn't we add the drug dosage onto the _mL for the other problems?)

You are injecting the 10mL of medication into the 50mL bag of solution. 10mL + 50mL = 60 mL total to be infused.

You should be calculating drip rate for total volume after med is added for each equation. Not sure why your answer key is picking and choosing to do it with some and not all.

Have your instructors gone over this with you at all? If they have and you're struggling this much, then you may want to meet with them.

The good news in that in reality, PB bags normally come ready-mixed from the pharmacy, which makes it easier.

[cocostar]

We are given these problems to do over break and she has not gone over them with us ): So are you saying for problems 1-4, the total volume infused would be the the solution plus the dosage volume? For example, #1 would be 150ml+3.2ml=153.2ml so 153.2ml/60 min x 15 gtt/ml=38.3 gtt/min=38 gtt/min.

[NICUismylife, ADN, BSN, RN]

We are given these problems to do over break and she has not gone over them with us ): So are you saying for problems 1-4, the total volume infused would be the the solution plus the dosage volume? For example, #1 would be 150ml+3.2ml=153.2ml so 153.2ml/60 min x 15 gtt/ml=38.3 gtt/min=38 gtt/min.

Right!