How many total drops would be delivered during an 8-hour infusion of 400 mL with a drop factor of 20 gtt/mL?

How many total drops would be delivered during an 8-hour infusion of 400 mL with a drop factor of 20 gtt/mL?

• A. 4000
• B. 12000
• C. 2000
• D. 8000

Answer: (D)

The main idea here is that the drop factor tells you how many drops constitute one milliliter. To get the total drops for a given volume, multiply the volume by the drop factor: 400 mL × 20 gtt/mL = 8000 drops. The 8-hour duration isn’t needed to find the total number of drops, but it can be used to check the rate: the infusion would be 50 mL/hour, which equals 50 × 20 = 1000 drops/hour, or about 16.7 drops per minute. Over 8 hours, that also totals about 8000 drops.

The main idea here is that the drop factor tells you how many drops constitute one milliliter. To get the total drops for a given volume, multiply the volume by the drop factor: 400 mL × 20 gtt/mL = 8000 drops. The 8-hour duration isn’t needed to find the total number of drops, but it can be used to check the rate: the infusion would be 50 mL/hour, which equals 50 × 20 = 1000 drops/hour, or about 16.7 drops per minute. Over 8 hours, that also totals about 8000 drops.