Question

A patient who is admitted to the hospital begins receiving 1 L IV solution intravenously as a continuous infusion on Monday at 8:00 AM at a rate of 30 mL/hr. An order is received for the patient to increase the flow rate of the IV solution to 45 mL/hr. The nurse increases the rate at 12:30 PM on the same day. Calculate when would the nurse have to start another 1- liter IV bag for this patient?

I. Monday at 20:30

II. Tuesday at 07:45

III. Tuesday at 20:15

IV. Wednesday at 08:05

Answer 1

IV infusion is started at 8am on monday at 30 mL / hour. Then order is changed to 45 mL / hour from 12.30 pm .

So from 8 am to 12.30 pm there is 4.5 hours,during which iv infusion was at 30 mL / hour.

Total fluid infused during this 4.5 hours = 4.5 x 30 = 135 mL

For infusion 1 litre bag is used,that means 1000 mL.So at 12.30 pm on monday the remaining fluid in the IV bag will be 1000 mL - 135 mL = 865 mL

At 12.30 pm infusion rate is changed to 45 mL / hour.

So now, we have to calculate how many hours it will take to infuse 865 mL.

1 hour = 45 mL

X hour = 865 mL

X = 865 / 45 = 19.2 hours = 19 hours 20 minutes

So the nurse has to start next 1 litre bag after 19 hours 20 minutes form 12.30 pm on monday.

In this 19 hours 20 minutes, 11 hours 30 minutes will fall on monday since infusion was started at 12.30 pm on monday.( 24 hours - 12 hours 30 minutes =11 hours 30 minutes)

Remaining hours are 7 hours 50 minutes, and it will fall on tuesday ( 19 hours 20 minutes - 11 hour 30 minutes = 7 hours 50 minutes)

That is at 7.50 am on tuesday ,nearest anwser is 7.45 on tuesday.