When expressing IV flow rate, which unit is used?

When expressing IV flow rate, which unit is used?

• A. Gtt/min
• B. mL/hr
• C. L/min
• D. cc/min

Answer: (A)

For gravity IV therapy, the flow rate is expressed as drops per minute (gtt/min) because you’re measuring how many drops of fluid enter the patient each minute. The tubing has a fixed drop factor (gtt per mL), so the rate you see and adjust is the actual drop count per minute, not a volume per hour. To calculate it, you multiply the total volume to be infused (in mL) by the drop factor (gtt/mL) and divide by the time (in minutes): Rate = (volume in mL) × (drop factor in gtt/mL) ÷ (time in minutes), giving a result in gtt/min. Example: If you need to infuse 500 mL over 60 minutes with a 15 gtt/mL set, the rate is 500 × 15 ÷ 60 ≈ 125 gtt/min. If you were using an IV pump instead of gravity, you’d typically report the rate in mL/hr, but the question is specifically about gravity-driven flow, which uses gtt/min.

For gravity IV therapy, the flow rate is expressed as drops per minute (gtt/min) because you’re measuring how many drops of fluid enter the patient each minute. The tubing has a fixed drop factor (gtt per mL), so the rate you see and adjust is the actual drop count per minute, not a volume per hour. To calculate it, you multiply the total volume to be infused (in mL) by the drop factor (gtt/mL) and divide by the time (in minutes): Rate = (volume in mL) × (drop factor in gtt/mL) ÷ (time in minutes), giving a result in gtt/min.

Example: If you need to infuse 500 mL over 60 minutes with a 15 gtt/mL set, the rate is 500 × 15 ÷ 60 ≈ 125 gtt/min.

If you were using an IV pump instead of gravity, you’d typically report the rate in mL/hr, but the question is specifically about gravity-driven flow, which uses gtt/min.