One unit of packed cells is to be given over 3 hours, using a giving set that delivers 20 gtt/mL. If the unit contains 250 mL, what is the drip rate in drops per minute?

One unit of packed cells is to be given over 3 hours, using a giving set that delivers 20 gtt/mL. If the unit contains 250 mL, what is the drip rate in drops per minute?

• A. 25 gtt/min
• B. 28 gtt/min
• C. 30 gtt/min
• D. 32 gtt/min

Answer: (B)

Think in terms of flow rate and convert to drops using the drip factor. The unit is 250 mL over 3 hours, which is 180 minutes, so the infusion rate is 250 / 180 ≈ 1.389 mL per minute. The giving set delivers 20 drops per mL, so the rate in drops per minute is 1.389 × 20 ≈ 27.78 drops/min, which rounds to 28 drops per minute. So the drip rate is 28 gtt/min.

Think in terms of flow rate and convert to drops using the drip factor. The unit is 250 mL over 3 hours, which is 180 minutes, so the infusion rate is 250 / 180 ≈ 1.389 mL per minute. The giving set delivers 20 drops per mL, so the rate in drops per minute is 1.389 × 20 ≈ 27.78 drops/min, which rounds to 28 drops per minute. So the drip rate is 28 gtt/min.