unfractionated heparin

Stop IV infusion 4-6 hours preoperatively (if APTT is within target range). 

Restart >/= 12 hours postop (no bolus) if no bleeding evident.

Discontinue S/C therapy 12 hours preop. 

Restart >/= 12 hours postop if no bleeding evident.

Avoid IM route preoperatively unless no other route is available.