For a 250-mL unit of packed RBCs to be infused over 2 hours, what should the flow rate be in drops per minute using a drop factor of 15 gtts/mL?

To determine the correct flow rate in drops per minute for a 250-mL unit of packed RBCs to be infused over 2 hours, it’s essential to first convert the total infusion time from hours to minutes. Since there are 60 minutes in an hour, 2 hours equals 120 minutes.

Next, to find the flow rate in mL per minute, you divide the total volume of the packed RBCs by the infusion time in minutes:

250 mL ÷ 120 minutes = approximately 2.08 mL/min.

Now, to convert this flow rate in mL per minute to drops per minute, you need to multiply the flow rate in mL/min by the drop factor of the infusion set, which is given as 15 gtts/mL:

2.08 mL/min × 15 gtts/mL = 31.2 gtt/min.

Rounding this value to the nearest whole number gives you a flow rate of 31 gtt/min. This flow rate aligns with the chosen answer and accurately reflects the calculations needed for administering a blood transfusion using the specified drop factor.