How do you distinguish normal post-operative pain and swelling in an extremity from a post-operative complication such as hemorrhage, surgical site infection, etc.?

That is a good question. I would first ask the patient if their pain (and/or swelling) is any different (or worse). A change in the pain (or the recurrence of pain) could be a sign of a postoperative complication. Swelling beyond the first postoperative day, especially with erythema/warmth, could indicate an infection. The vital signs are sometimes helpful. Fevers in the first 48 hours after surgery are usually from the cytokine response to surgery. However, fevers beyond this time could be an indication of an infection. Complaints of new pain and/or new erythema and/or new swelling in the setting of fever could be an indication of a postoperative infection (or postoperative bleeding). The physical exam is also important. Examining the extr...