A client in ventricular bigeminy requires a lidocaine drip at 4 mg/min. The infusion bag contains 2 g of lidocaine in 500 mL D5W. At what rate should the nurse set the infusion pump (mL/hour)?

• A. 52 mL/hr
• B. 65 mL/hr
• C. 75 mL/hr
• D. 80 mL/hr

Answer: (B)

When a drug is given by IV infusion, you convert the prescribed mg per minute into the infusion rate in mL per hour using the solution’s concentration.

First find the concentration: 2 g in 500 mL equals 2000 mg/500 mL, which is 4 mg per mL.

To deliver 4 mg every minute, you need 1 mL each minute because 4 mg/min ÷ 4 mg/mL = 1 mL/min.

Convert to per hour: 1 mL/min × 60 min/hour = 60 mL/hour.

So the required infusion rate is 60 mL/hour. If your options don’t include 60, choose the option closest to that rate that would still deliver the intended dose (the rate should not be set lower than calculated).