The physician orders 1.5 litres of Lactated Ringers to be infused over 12 hours. The IV tubing delivers 15 gtt per mL. What is the rate in drops per minute (nearest whole number)?

The physician orders 1.5 litres of Lactated Ringers to be infused over 12 hours. The IV tubing delivers 15 gtt per mL. What is the rate in drops per minute (nearest whole number)?

• A. 31 gtt/min
• B. 25 gtt/min
• C. 36 gtt/min
• D. 42 gtt/min

Answer: (A)

The rate in gtt/min comes from how many milliliters are delivered per minute and how many drops are in each milliliter. Convert the volume and time: 1.5 liters is 1500 mL, and 12 hours is 720 minutes. So the infusion is 1500 mL / 720 min ≈ 2.083 mL per minute. With a drip factor of 15 drops per mL, the rate is 2.083 mL/min × 15 gtt/mL ≈ 31.25 gtt/min. Rounding to the nearest whole drop gives 31 gtt/min.

The rate in gtt/min comes from how many milliliters are delivered per minute and how many drops are in each milliliter. Convert the volume and time: 1.5 liters is 1500 mL, and 12 hours is 720 minutes. So the infusion is 1500 mL / 720 min ≈ 2.083 mL per minute. With a drip factor of 15 drops per mL, the rate is 2.083 mL/min × 15 gtt/mL ≈ 31.25 gtt/min. Rounding to the nearest whole drop gives 31 gtt/min.