An elderly patient has had hip surgery and will be receiving heparin, 4000 units subcutaneously every 12 hours. The heparin is available in vials of 5000 units/mL. Calculate how much heparin the nurse will administer for this dose.

Determine the volume of heparin to administer. The ordered dose is 4000 units and the available concentration is 5000 units/mL. The calculation is 4000 units ÷ (5000 units/mL) = 0.8 mL. The nurse will administer 0.8 mL of heparin for this dose.