Infuse 500 mL over 4 hours with a microdrip set (60 gtt/mL). What is the rate in gtt/min?

Infuse 500 mL over 4 hours with a microdrip set (60 gtt/mL). What is the rate in gtt/min?

• A. 75 gtt/min
• B. 125 gtt/min
• C. 250 gtt/min
• D. 100 gtt/min

Answer: (B)

To get drops per minute, use rate = (volume × drop factor) ÷ time in minutes. Here, 500 mL at 60 gtt/mL over 4 hours equals 240 minutes. So rate = (500 × 60) ÷ 240 = 30,000 ÷ 240 = 125 gtt/min. You can also see it as 500 mL/4 h = 125 mL/hour; 125 mL/hour × 60 gtt/mL = 7,500 gtt/hour; 7,500 ÷ 60 min = 125 gtt/min. Therefore, the rate is 125 gtt/min.

To get drops per minute, use rate = (volume × drop factor) ÷ time in minutes. Here, 500 mL at 60 gtt/mL over 4 hours equals 240 minutes. So rate = (500 × 60) ÷ 240 = 30,000 ÷ 240 = 125 gtt/min. You can also see it as 500 mL/4 h = 125 mL/hour; 125 mL/hour × 60 gtt/mL = 7,500 gtt/hour; 7,500 ÷ 60 min = 125 gtt/min. Therefore, the rate is 125 gtt/min.