A patient weighs 154 pounds and is prescribed heparin at 15 units/kg/hr. The heparin solution is labeled 25,000 units in 250 mL of D5W. What is the correct infusion rate in mL/hr? Round to the nearest whole number.

• A. 9 mL/hr
• B. 11 mL/hr
• C. 10 mL/hr
• D. 12 mL/hr

Answer: (B)

The main concept is to translate a weight-based dose into a flow rate using the solution’s concentration. First convert the patient’s weight to kilograms, then calculate the required units per hour, and finally convert that to milliliters per hour using the concentration, rounding to the nearest whole number.

Convert weight: 154 pounds is about 70 kilograms (using 2.2 lb per kg). Multiply by the ordered dose: 70 kg × 15 units/kg/hr = 1050 units/hr.

Concentration: the solution has 25,000 units in 250 mL, which is 100 units per mL.

Convert to mL per hour: 1050 units/hr ÷ 100 units/mL = 10.5 mL/hr.

Round to the nearest whole number: 10.5 rounds to 11 mL/hr.

Thus, the correct infusion rate is 11 mL/hr. If you used a more precise weight (69.8 kg) you’d get about 10.48 mL/hr, which would round to 10, but in typical clinical rounding for dose calculations, using 70 kg gives the 11 mL/hr result that aligns with the standard rounding approach used in practice.