A 500 mL IV bag is to be infused over 4 hours using a giving set that delivers 20 drops/mL. What is the required drip rate in drops per minute?

A 500 mL IV bag is to be infused over 4 hours using a giving set that delivers 20 drops/mL. What is the required drip rate in drops per minute?

• A. 41 gtt/min
• B. 42 gtt/min
• C. 39 gtt/min
• D. 44 gtt/min

Answer: (B)

The rate in drops per minute comes from converting the total infusion into drops per minute using the drip factor. First convert the time: 4 hours is 240 minutes, so the infusion rate is 500 mL / 240 min ≈ 2.083 mL/min. With a drip factor of 20 drops per mL, multiply: 2.083 mL/min × 20 drops/mL ≈ 41.7 drops/min. Since you deliver whole drops, round to the nearest whole drop, giving 42 drops per minute.

The rate in drops per minute comes from converting the total infusion into drops per minute using the drip factor. First convert the time: 4 hours is 240 minutes, so the infusion rate is 500 mL / 240 min ≈ 2.083 mL/min. With a drip factor of 20 drops per mL, multiply: 2.083 mL/min × 20 drops/mL ≈ 41.7 drops/min. Since you deliver whole drops, round to the nearest whole drop, giving 42 drops per minute.