For the heparin example, at 20 mL/h, how many units are delivered in 4 hours?

For the heparin example, at 20 mL/h, how many units are delivered in 4 hours?

• A. 800 units
• B. 1200 units
• C. 1600 units
• D. 2000 units

Answer: (C)

The key idea is to convert the infusion rate from mL/hour to units/hour using the drug's concentration, then multiply by the time to get total units. If the heparin is 20 units per mL, the delivery is 20 mL/hour × 20 units/mL = 400 units per hour. Over 4 hours, that’s 400 × 4 = 1600 units. So, 1600 units are delivered in 4 hours.

The key idea is to convert the infusion rate from mL/hour to units/hour using the drug's concentration, then multiply by the time to get total units.

If the heparin is 20 units per mL, the delivery is 20 mL/hour × 20 units/mL = 400 units per hour. Over 4 hours, that’s 400 × 4 = 1600 units.

So, 1600 units are delivered in 4 hours.