Ivpb dosage calculation help

[Grnbay]

I need help. I don't know if it's the way I'm processing this information, but I just can't seem to setup up my dimension analysis.

Order: Daptomycin 4mg/kg IVPB over 30 minutes once daily for bacterial infection.

Supply: 500 mg vial

client's weight: 185 lb

Nursing drug reference: reconstitute with 10 mL of 0.9% sodium chloride and further dilute in 50 mL of 0.9% sodium chloride to yield 50 mg/mL.

Calculate the milliliters per hour to set the IV pump.

[Here.I.Stand, BSN, RN]

Where are you getting stuck? Have you figured out the ordered dose yet?

[dmapp63, MSN, RN]

Don't get distracted by "extra" info in the scenario.

You are asked to set the pump in mL per hour - so what is your final volume once you mix your med bag and how long is it ordered to infuse?

[Rose_Queen, BSN, MSN, RN]

Ok, so this is one that you can easily break down into steps.

First, what is the problem asking you?

What do you need to do with some of the information in the question in order to calculate your final answer?

Tell us what you think the first step should be.

[Rose_Queen, BSN, MSN, RN]

Don't get distracted by "extra" info in the scenario.

You are asked to set the pump in mL per hour - so what is your final volume once you mix your med bag and how long is it ordered to infuse?

Except that just giving the med bag doesn't take into account the 4mg/kg. OP really does need all of the information provided in the problem.

[Grnbay]

This is how I would set this equation up

4mg/kg x mL/50mg x 30min x 60min/1hr x 185lbs x 1kg/2.2 lbs

I got 134.5 mL/hr

Please correct help me correct my error, thank you.

[chare]

[…-

Nursing drug reference: reconstitute with 10 mL of 0.9% sodium chloride and further dilute in 50 mL of 0.9% sodium chloride to yield 50 mg/mL.

[…]

This is incorrect; 50 mg/mL is the concentration of you reconstituted medication.

[…]

I got 134.5 mL/hr

[…]

134.5 mL/hour is not correct.

Rather than trying to complete this is one long calculation, I would do this in three separate stages.

1. Calculate how many mg the total dose would be, and how many mL of the reconstituted medication are required.

2. Add the volume of medication previously determined to 50 mL of 0.9% NaCl to determine the total volume to be administered

3. Calculate your infusion rate using the total volume to be delivered

[…]

4mg/kg x mL/50mg x 30min x 60min/1hr x 185lbs x 1kg/2.2 lbs

[…]

Your equation includes everything that you need to determine the total dose of medication, as well as the volume. I have deleted the information that you don't need to for this step. When I set up the problem I try to arrange it so that all calculations required for each stage are together. For example, with the information you have, you need to determine how many mL of daptomycin you need. I would first determine how many mg you will administer, then the volume. To do this, I would set my equation up as follows: 4 mg/1kg x 1 kg/2.2 lbs x 185 lbs/1 x 1 mL/50 mg.

[Anonymous865]

This is how I would set this equation up

4mg/kg x mL/50mg x 30min x 60min/1hr x 185lbs x 1kg/2.2 lbs

I got 134.5 mL/hr

Please correct help me correct my error, thank you.

Your mistake is with 30 min x 60 min/1hour

Your goal is to eliminate the "minutes" from the equation, so that the answer uses the unit hours. You can eliminate a unit of measure when it occurs in both the numerator and in the denominator.

e.g. 30 min x 1 hour / 60 minutes

or 1/30 min x 60 min / hour

In both equations you can eliminate "minutes" because the unit of measure is in both the numerator and the denominator.

You want your final answer to be in mls / hour, so which of the above equations do you think is correct?

(Also note that this will answer the question posed which was "Calculate the milliliters per hour to set the pump." This does not tell you the dose the patient should receive.)