A 500 mL infusion is set to run over 8 hours with a giving set of 20 drops/mL. What is the drip rate in drops per minute?

A 500 mL infusion is set to run over 8 hours with a giving set of 20 drops/mL. What is the drip rate in drops per minute?

• A. 20 gtt/min
• B. 22 gtt/min
• C. 19 gtt/min
• D. 21 gtt/min

Answer: (D)

The key idea is converting the prescribed volume over time into a flow rate in drops per minute using the giving set’s drop factor. First find how many milliliters per hour the infusion delivers: 500 mL divided by 8 hours equals 62.5 mL per hour. Next convert that to drops per hour using the giving set: 62.5 mL/h × 20 drops/mL = 1250 drops per hour. Then convert to drops per minute: 1250 drops per hour ÷ 60 minutes per hour ≈ 20.83 drops per minute. In practice, you report this as 21 drops per minute because you can’t deliver a fraction of a drop. So the drip rate is about 21 gtt/min.

The key idea is converting the prescribed volume over time into a flow rate in drops per minute using the giving set’s drop factor.

First find how many milliliters per hour the infusion delivers: 500 mL divided by 8 hours equals 62.5 mL per hour.

Next convert that to drops per hour using the giving set: 62.5 mL/h × 20 drops/mL = 1250 drops per hour.

Then convert to drops per minute: 1250 drops per hour ÷ 60 minutes per hour ≈ 20.83 drops per minute. In practice, you report this as 21 drops per minute because you can’t deliver a fraction of a drop.

So the drip rate is about 21 gtt/min.