# Dosage problem help

Student Assist   (846 Views | 6 Replies)

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I've been staring at this problem for the past 20 minutes and can't figure out where to start. I'm feeling pretty dumb because flow rate problems usually aren't an issue for me, and this one seems pretty straightforward. Any help would be appreciated.

There is 400ml left in the IV bag at 0900 hours. It is infusing at 20gtt/min. The drop factor is 10gtt/ml . At what time will the next bag be needed?

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hon918 is a ADN, RN and specializes in ICU.

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Start by calculating the flow rate in ml/min.

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Esme12 has 40 years experience as a ASN, BSN, RN and specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

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bgxyrnf has 10 years experience as a MSN, RN and specializes in Med-Tele; ED; ICU.

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I've been staring at this problem for the past 20 minutes and can't figure out where to start. I'm feeling pretty dumb because flow rate problems usually aren't an issue for me, and this one seems pretty straightforward. Any help would be appreciated.

There is 400ml left in the IV bag at 0900 hours. It is infusing at 20gtt/min. The drop factor is 10gtt/ml . At what time will the next bag be needed?

I presume that you figured it out for yourself. If not, let me know and I'd be happy to guide you.

It is indeed very straightforward and hon918 has given you a nudge... convert the drip rate into a volumetric rate and go from there.

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10 Posts; 135 Profile Views

Flow rate (gtt/min)= volume/Time(ml/min) X Drop factor(gtt/ml)

400/T X 10gtt/ml = Flow rate(gtt/min)

Flow rate = 400 X 10/ T

Flow rate = 4000/T

Flow rate has been given in the question as 20gtt/min

Therefore: 20 = 4000/T

T = 4000/20 (min)

T = 200minutes

And 200 minutes, when converted to hours = 200/60

Because 60minutes = 1 hour

T = 3.33 hours

3hours plus -33hours

0-33 hours = 20mins

So, he will need another bag at 12:20pm

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382 Posts; 3,309 Profile Views

Hello! I see that someone already solved this and you haven't responded, so you probably already have it. But, just in case it helps you or someone else, I wanted to post how I solve this:

To calculate the time it will take to dispense the amount of fluid left in the bag use this formula:

Time (1hr/60 min) x Flow Rate (gtt/min) x Drop Factor (gtt/mL) x Volume Infused = Hours Remaining

Formula:

So, with your numbers put it in looks like this:

Solve the equation:

To compute the time:

60 x 0.33 hr = 19.8 = 20 min

Total infusion time = 3 hr and 20 min

So, you would change the bag at 12:20.

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10 Posts; 135 Profile Views

I've done it already and I've also posted it. I was the person that did it and posted it initially.