If you infuse 200 ml over 120 minutes with a drop factor of 20 gtt/ml, what is the gtt/min?

If you infuse 200 ml over 120 minutes with a drop factor of 20 gtt/ml, what is the gtt/min?

• A. 16
• B. 33
• C. 67
• D. 100

Answer: (C)

Calculating drops per minute hinges on multiplying how many milliliters you’re delivering by how many drops are in each milliliter, then spreading that total over the infusion time. The formula is: gtt/min = (volume in mL × drop factor in gtt/mL) ÷ time in minutes. Here, 200 mL over 120 minutes with a drop factor of 20 gtt/mL gives (200 × 20) = 4000 drops in total. Dividing by 120 minutes yields 4000 ÷ 120 ≈ 33.3 gtt/min, so about 33 gtt/min. This matches the option that shows 33 gtt/min. The other values would require different total drops or a different infusion duration, so they don’t fit the calculation.

Calculating drops per minute hinges on multiplying how many milliliters you’re delivering by how many drops are in each milliliter, then spreading that total over the infusion time. The formula is: gtt/min = (volume in mL × drop factor in gtt/mL) ÷ time in minutes.

Here, 200 mL over 120 minutes with a drop factor of 20 gtt/mL gives (200 × 20) = 4000 drops in total. Dividing by 120 minutes yields 4000 ÷ 120 ≈ 33.3 gtt/min, so about 33 gtt/min. This matches the option that shows 33 gtt/min.

The other values would require different total drops or a different infusion duration, so they don’t fit the calculation.