# Calculating infusion completion times

Published

An IV started at 2250 is to complete in 4 hr 20 min. Calculate the completion time.

2250

420

_______

2670

Change the 70 min to 1 hr 10 min=2710

Deduct 24 hr from 2710=0310 I don't understand this right here at all. How did it go from 2710 to 0310 can someone explain to me??

1 Article; 7,349 Posts

Specializes in Pedi. Has 16 years experience.
An IV started at 2250 is to complete in 4 hr 20 min. Calculate the completion time.

2250

420

_______

2670

Change the 70 min to 1 hr 10 min=2710

Deduct 24 hr from 2710=0310 I don't understand this right here at all. How did it go from 2710 to 0310 can someone explain to me??

22:50 is 10:50 PM. There is no such time as 27:10 because there are only 24 hrs in a day.

Honestly, you're making this more complicated than it needs to be. You add four hours to 22:50 and that takes you to 02:50. Twenty more minutes takes you to 03:10.

2 Articles; 5,114 Posts

It's a twenty-four hour clock.

Midnight is 0000 (or sometimes 2400)

One minute past midnight is (always) 0001

One am is 0100

two fifteen am is 0215

six am is 0600

Noon is 1200

One minute past noon is 1201

One pm is 1300

six pm is 1800

seven forty five pm is 1945

nine pm is 2100

Sometimes whole hours are just two digits--, 01, 05, 10, 14, 21... etc.

This eliminates confusion between am and pm in charting.

7 Posts

An IV started at 2250 is to complete in 4 hr 20 min. Calculate the completion time.

2250

420

_______

2670

Change the 70 min to 1 hr 10 min=2710

Deduct 24 hr from 2710=0310 I don't understand this right here at all. How did it go from 2710 to 0310 can someone explain to me??

For me, the easiest would be to add the 420 to the time it was started: 2250 + 420 = 2670. Once you get the 2670, then you will subtract 2400 (since you're working off of a 2400 clock) so 2670 - 2400 = 210. So 0210 (2:10 am) would be the completion time.

Hope it helps!

2 Articles; 5,114 Posts

Oopsy, brat514. 2670 - 2400 is not 210. It's 270, which is, in military time, 0310, ten past three am.

Try using a clock face to look at this problem. You have a start time and a duration of four hours and twenty minutes.

Start at 2250, 10:50 pm, ten minutes before 11pm.

Add twenty minutes: 11:10 pm. Add four hours. 3:10 am. Done. Kel had it right, and you should look at her arithmetic to see where she got it right and you missed it. There will be a lot of these questions in your future. :)

7 Posts

Oopsy, brat514. 2670 - 2400 is not 210. It's 270, which is, in military time, 0310, ten past three am.

Try using a clock face to look at this problem. You have a start time and a duration of four hours and twenty minutes.

Start at 2250, 10:50 pm, ten minutes before 11pm.

Add twenty minutes: 11:10 pm. Add four hours. 3:10 am. Done. Kel had it right, and you should look at her arithmetic to see where she got it right and you missed it. There will be a lot of these questions in your future. :)

Thank you grntea! Ya know, I had posted 0310 at first then overthought it and edited it. Oops!

To the OP, sorry! I hope I didn't confuse you even more

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