Worked example

IV drip rate (gtt/min) — practice problem 13

An order reads: infuse 100 mL of 0.9% normal saline over 2 hours by gravity. The tubing drop factor is 15 gtt/mL.

Volume100 mL
Time2 hr (120 min)
Drop factor15 gtt/mL

What is the drip rate in gtt/min?

Answer: 13 gtt/min

Step-by-step solution

1. Start from the flow rate and multiply by the drop factor
( 100 mL ÷ 120 min ) × ( 15 gtt ÷ 1 mL )
2. Cancel mL and solve
= ( 100 × 15 ) ÷ 120 gtt/min
= 12.5 gtt/min
3. Round to whole drops (you cannot count part of a drop)
12.5 gtt/min ≈ 13 gtt/min
= 13 gtt/min

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