Question

An IV containing heparin in 250 mL of NS is infusing at 40 drops per minute. The infusion set is a microdrop. What is the infusion time? ( 1 drop = 4 microdrops, 1 mL = 15 drops = 60 microdrops)

Answer 1

The formula for infusion time is = total volume in ML ÷ flow rate ML per hour .

So here 1 mL = 15 drops , total volume is 250 ML (given with heparin and normal saline )

To calculate infustion time we need total volume and flow rate in ml per hour , so total volume is 250 ml

To calculate flow rate in ML per hour we will calculate the drop per minute from the given value 250 ML . So the formula for calculating drop per minut is total volume in ML divide by time in minutes .

For example we will calculate 250 ML divide by 60 minutes which will give 42 drops per minute .

Now calculate this 40 drops per minute into ML per hour

So convert 42 drops per minute to ML per hour which will be 126 ML per hour .

Now , the infusion time will be total volume ÷ flow rate ml per hour

Which is 250 ÷ 126 = 1.98 minutes (118 minutes) , so the infusion time for 250 ML solution will be approximately 1.98 minutes that is 2 hours .