A 73 year old lady underwent degenerative scoliosis surgery, instrumented fusion from T10 to S1. Had one dose of unfractionated heparin 5000 units 12 hours before surgery and was restarted 12 hours after surgery at 5000 units SC 8th hourly for 7 days. From day 6 she had oozing in the wound and on re-exploration 200 gms of the clot was evacuated. All parameters except fibrinogen which was mildly reduced were normal.
Hb dropped from 12gm to 8. Per and post op she received 3 units of packed cells transfusion. What could have been the probable cause?
