Ampicillin 500 mg dissolved in 100 mL D5W to run for 1 hour. The drop factor is 10 gtt/mL. What is the correct flow rate?

Ampicillin 500 mg dissolved in 100 mL D5W to run for 1 hour. The drop factor is 10 gtt/mL. What is the correct flow rate?

• A. 16 gtt/min
• B. 15 gtt/min
• C. 17 gtt/min
• D. 18 gtt/min

Answer: (C)

IV flow rate calculation uses volume, time, and drop factor to determine drops per minute. Flow rate (gtt/min) = (volume in mL) × (drop factor in gtt/mL) ÷ (time in minutes). Here, 100 mL over 60 minutes with a drop factor of 10 gtt/mL gives (100 × 10) ÷ 60 = 1000/60 ≈ 16.7 gtt/min. Round to the nearest whole drop per minute, which is 17 gtt/min. So the correct flow rate is 17 gtt/min. This is closest to the exact value; 16 would under-deliver slightly, while 15 or 18 are farther from the calculated rate.

IV flow rate calculation uses volume, time, and drop factor to determine drops per minute. Flow rate (gtt/min) = (volume in mL) × (drop factor in gtt/mL) ÷ (time in minutes). Here, 100 mL over 60 minutes with a drop factor of 10 gtt/mL gives (100 × 10) ÷ 60 = 1000/60 ≈ 16.7 gtt/min. Round to the nearest whole drop per minute, which is 17 gtt/min. So the correct flow rate is 17 gtt/min. This is closest to the exact value; 16 would under-deliver slightly, while 15 or 18 are farther from the calculated rate.