The nurse is to calculate gtt/min to transfuse one unit (300 mL) of Packed Red Blood Cells (PRBC 's) over two hours using blood tubing that has a drop factor of 10 gtts/min

A. 15: This rate would result in the unit being infused over 4 hours, which is slower than the prescribed 2-hour duration. Under-infusion can delay treatment and reduce the effectiveness of oxygen delivery from PRBCs. B. 25: To calculate drops per minute: use the formula (Volume in mL × Drop factor in gtts/mL) ÷ Time in minutes. Here, (300 × 10) ÷ 120 = 3000 ÷ 120 = 25 gtts/min. This rate will ensure the unit is transfused over 2 hours as prescribed. C. 20: Infusing at 20 gtts/min would extend the transfusion slightly beyond 2 hours, resulting in under-delivery of the blood unit within the intended time frame. D. 10: This rate is far too slow; the transfusion would take 5 hours, significantly exceeding the prescribed time and delaying treatment.