An anemic patient must be given one unit of packed cells over 4 hours. The unit of packed cells holds 250 mL. The I.V. set delivers 20 drops per mL. What is the required drip rate in drops per minute for the blood infusion?

An anemic patient must be given one unit of packed cells over 4 hours. The unit of packed cells holds 250 mL. The I.V. set delivers 20 drops per mL. What is the required drip rate in drops per minute for the blood infusion?

• A. 21 gtt/min
• B. 20 gtt/min
• C. 22 gtt/min
• D. 23 gtt/min

Answer: (A)

The test is about turning a prescribed volume over a set time into a drip rate using the drop factor. Start by finding how fast the infusion should run in milliliters per hour: 250 mL over 4 hours equals 62.5 mL/hour. Next, convert that to milliliters per minute: 62.5 mL/hour ÷ 60 minutes/hour ≈ 1.0417 mL/min. With a drop factor of 20 drops per milliliter, the rate in drops per minute is 1.0417 mL/min × 20 drops/mL ≈ 20.83 drops/min. Since you can’t deliver a fraction of a drop, round to the nearest whole drop, giving about 21 drops per minute. This aligns with checking total drops per hour: 62.5 mL/hour × 20 drops/mL = 1250 drops/hour, and 1250 drops/hour ÷ 60 minutes/hour ≈ 20.83 drops/min ≈ 21 gtt/min. The other options would correspond to different infusion speeds that don’t match the required 250 mL over 4 hours.

The test is about turning a prescribed volume over a set time into a drip rate using the drop factor. Start by finding how fast the infusion should run in milliliters per hour: 250 mL over 4 hours equals 62.5 mL/hour. Next, convert that to milliliters per minute: 62.5 mL/hour ÷ 60 minutes/hour ≈ 1.0417 mL/min. With a drop factor of 20 drops per milliliter, the rate in drops per minute is 1.0417 mL/min × 20 drops/mL ≈ 20.83 drops/min. Since you can’t deliver a fraction of a drop, round to the nearest whole drop, giving about 21 drops per minute.

This aligns with checking total drops per hour: 62.5 mL/hour × 20 drops/mL = 1250 drops/hour, and 1250 drops/hour ÷ 60 minutes/hour ≈ 20.83 drops/min ≈ 21 gtt/min. The other options would correspond to different infusion speeds that don’t match the required 250 mL over 4 hours.