A patient is to receive 900 mL D5W by IV over 8 hours. The IV set delivers 15 gtt/mL. What is the flow rate in gtt/min?

A patient is to receive 900 mL D5W by IV over 8 hours. The IV set delivers 15 gtt/mL. What is the flow rate in gtt/min?

• A. 26 gtt/min
• B. 29 gtt/min
• C. 28 gtt/min
• D. 32 gtt/min

Answer: (C)

The main idea is to convert the prescribed volume and time into a drops-per-minute rate using the drip factor. Use the formula: flow rate (gtt/min) = (volume in mL) × (drip factor in gtt/mL) ÷ (time in minutes). Here, 900 mL to infuse over 8 hours. Convert the time to minutes: 8 hours × 60 = 480 minutes. So the calculation is 900 × 15 ÷ 480 = 13,500 ÷ 480 ≈ 28.125 gtt/min. Since drops are counted in whole units, round to the nearest whole drop per minute, giving about 28 gtt/min. That matches the option closest to this value. The exact result is just over 28, so the 28 gtt/min choice is the best fit.

The main idea is to convert the prescribed volume and time into a drops-per-minute rate using the drip factor. Use the formula: flow rate (gtt/min) = (volume in mL) × (drip factor in gtt/mL) ÷ (time in minutes).

Here, 900 mL to infuse over 8 hours. Convert the time to minutes: 8 hours × 60 = 480 minutes. So the calculation is 900 × 15 ÷ 480 = 13,500 ÷ 480 ≈ 28.125 gtt/min. Since drops are counted in whole units, round to the nearest whole drop per minute, giving about 28 gtt/min.

That matches the option closest to this value. The exact result is just over 28, so the 28 gtt/min choice is the best fit.