An order calls for 1,250 mL of IV fluid to infuse by gravity over 10 hours. The tubing delivers 20 drops (gtt) per milliliter. At what rate, in drops per minute, should the fluid run? Round to the nearest whole drop.
- A125 gtt/min
- B6 gtt/min
- C2,500 gtt/min
- D42 gtt/min
Show the answer and why
Correct answer: D
Start with the hourly rate: 1,250 mL ÷ 10 h = 125 mL/h. Multiply by the drop factor to get drops per hour (125 × 20 = 2,500 gtt/h), then divide by 60 minutes: 2,500 ÷ 60 ≈ 41.67, which rounds to 42 gtt/min. Writing the units at each step (mL/h × gtt/mL ÷ min/h = gtt/min) shows whether a step is missing.
- AThis is the rate in mL per hour (1,250 ÷ 10); it was never changed to drops or to minutes.
- BThis divides by the drop factor instead of multiplying (1,250 ÷ (10 × 20) = 6.25 ≈ 6).
- CThis is the number of drops per hour; the last step, dividing by 60 minutes, is missing.
- DCorrect: (1,250 ÷ 10) × 20 ÷ 60 ≈ 41.67, which rounds to 42 gtt/min.
Source: OpenStax Clinical Nursing Skills, 13.3 Intravenous Infusion