# IVPB dosage calculations

Updated | Posted
by caprisgoddess (New)

One more question I have pertaining to dosage calculations LOL and then I will leave you alone:-) I am not understanding this problem

Physcian Order: Gentamicin 200mg IVPB every 6 hours

On hand: 200 mg in 100 mL D5W to be administered over 30 min.

Thanks again you have been such a great help:-)!

so you would put in 200ml an hour and that the bag has 100 ml which would run the bag over 30 min, does that answer your question?

Specializes in med/surg, telemetry, IV therapy, mgmt. Has 40 years experience.

physcian order: gentamicin 200mg ivpb every 6 hours

on hand: 200 mg in 100 ml d5w to be administered over 30 min.

if the ivpb is infusing via an iv pump, you must know that the infusion rate of the pump is programmed in
ml per hour
. then,

100 ml
(amount to give)
/30 minutes
(time over which it is to be infused)
x 60 minutes/1 hour
(conversion factor)
=
200 ml/hour
(infusion rate to program on the iv pump)

the important unit you want/need to pay attention to in this problem is the ml and the time to be administered over.

physcian order: gentamicin 200mg ivpb every 6 hours

on hand: 200 mg in 100 ml d5w to be administered over 30 min.

100 ml

----------- = 3.3 drops per min

30 min

the patient will receive 200mg in 30 min at a rate of 3.3 drops/ min because there are 200mg of medication per 100 ml of solution and it must be administered within 30 min.

stated another way

in order for the patient to receive 100 ml of the ivpb containing 200 mg of the gentamycin it would be given at a rate of approxiamately 3.3 drops per min. do the math 3.3 * 30ml = 99 - 100 ml

hope this helps!!

daytonite,

not to step on your toes but:

"100 ml (amount to give)/30 minutes (time over which it is to be infused) x 60 minutes/1 hour (conversion factor) = 200 ml/hour (infusion rate to program on the iv pump)"

if the patient receives this, am i correct in saying that if there are 200 mg per 100 ml and the patient according to your calculations gets 200 ml/hr then the patient would be getting 400mg of gentamycin per hour??? when they are to only receive 200 mg every 6 hours?

please correct me if i'm wrong.

Specializes in med/surg, telemetry, IV therapy, mgmt. Has 40 years experience.

candygyrl said:
daytonite,

not to step on your toes but:

"100 ml (amount to give)/30 minutes (time over which it is to be infused) x 60 minutes/1 hour (conversion factor) = 200 ml/hour (infusion rate to program on the iv pump)"

if the patient receives this, am I correct in saying that if there are 200 mg per 100 ml and the patient according to your calculations gets 200 ml/hr then the patient would be getting 400mg of gentamycin per hour??? when they are to only receive 200 mg every 6 hours?

please correct me if I'm wrong.

the patient can only get 200 mg of the gentamycin because there is only 200 mg of it in a piggyback bag that has 100ml of fluid in it. that has never changed.

what has changed is the rate of infusion. you will merely be setting the infusion rate at 200ml/hour so that the 100ml of fluid with the 200 mg of drug in it gets infused into the patient in the 30 minute time period that the doctor ordered. it might help if you draw simple box figures to help you see what is going on here.

Specializes in med/surg, telemetry, IV therapy, mgmt. Has 40 years experience.

candygyrl said:
the important unit you want/need to pay attention to in this problem is the ml and the time to be administered over.

physcian order: gentamicin 200mg ivpb every 6 hours

on hand: 200 mg in 100 ml d5w to be administered over 30 min.

100 ml

----------- = 3.3 drops per min

30 min

the patient will receive 200mg in 30 min at a rate of 3.3 drops/ min because there are 200mg of medication per 100 ml of solution and it must be administered within 30 min.

stated another way

in order for the patient to receive 100 ml of the ivpb containing 200 mg of the gentamycin it would be given at a rate of approxiamately 3.3 drops per min. do the math 3.3 * 30ml = 99 - 100 ml

hope this helps!!

you cannot calculate drip rates without applying a drop factor for a specific iv tubing that is being used. drop factor for iv tubings are placed in equations as mls/1 minute for the specific tubing being used and you don't have that information or add it properly.

" (conversion factor) = 200 ml/hour (infusion rate to program on the iv pump)"

i see now that you were specifically reffering to how you would set it up on the iv pump in the hospital...

"one more question i have pertaining to dosage calculations lol and then i will leave you alone:-) i am not understanding this problem

physcian order: gentamicin 200mg ivpb every 6 hours

on hand: 200 mg in 100 ml d5w to be administered over 30 min."

i interpreted the original question to be that of a math dosage calculation practice problem/question used for testing purposes. when i had to take mine, alot of our questions looked very similar and never did we apply information pertaining to how the rate is to be programmed on the iv pump in the hospital setting-- we stuck mainly to the math.

"you cannot calculate drip rates without applying a drop factor for a specific iv tubing that is being used. drop factor for iv tubings are placed in equations as mls/1 minute for the specific tubing being used and you don't have that information or add it properly"

i did take this into consideration but considering 10, 15, or 60 as gtt factor was not included in the problem i tried not to take the question beyond the numbers as this was many a mistake i'd made during a few of my own practice problems until my instructor politely reminded me that this was a dosage calculation session where we are focusing on your ability to calculate the numbers in front of you so that when something doesn't look right you have the knowledge and capacity to check for yourself.

thanks for the clarification though... it was just a misunderstanding.

Specializes in Practical nursing.

Here's the problem...

Ordered Dilantin IV 375 mg now and then 50 mg/hr cont. infusion. It comes mixed in 1.5 Gm Dilantin in 1000 ml's NS bag. How many mg's per ml is in this mixture?

How many ml's per hour will you set the pump for the first NOW order/dosage infusion?

What will you set the lockout on the pump for the first NOW order?

How many ml's per hour will you set the pump after the first NOW infusion has infused for the next ordered continuous 50 mg/hr?

What will you set the lockout on the pump for this continuous infusion? (remember to calculate the original NOW order volume)

Specializes in Med Surg - Renal.

studentmomme said:

Here's the problem...

Ordered Dilantin IV 375 mg now and then 50 mg/hr cont. infusion. It comes mixed in 1.5 Gm Dilantin in 1000 ml's NS bag. How many mg's per ml is in this mixture?

How many ml's per hour will you set the pump for the first NOW order/dosage infusion?

What will you set the lockout on the pump for the first NOW order?

How many ml's per hour will you set the pump after the first NOW infusion has infused for the next ordered continuous 50 mg/hr?

What will you set the lockout on the pump for this continuous infusion? (remember to calculate the original NOW order volume)

Exactly which part of this problem are you having trouble with? If you answer these questions one by one, they are very straightforward.

Specializes in Practical nursing.

the lockout to be specific

Specializes in Med Surg - Renal.

By "lockout" I think they mean volume to be infused.

You have the dose, concentration, and rate, so find the volume you would program into the pump for the now infusion and the continuous infusion. I believe the question is directing you to use the same bag.

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