Effects of epidural anesthesia on incidence of venous thromboembolism following joint replacement

Deep vein thrombosis (DVT) and pulmonary embolism are serious complications following hip and knee replacement surgery. Both surgical procedures have significantly high postoperative rates of DVT. In total hip replacement, the rate of proximal thrombi tends to be higher. However, total knee replacement produces a high rate of calf thrombi and a higher overall rate of thrombosis. In a search for innovative ways to reduce the risk of thrombosis, three types of anesthesia were examined: general anesthesia, epidural anesthesia, and hypotensive epidural anesthesia in which a controlled hypotension is provided. The hypotension commonly exists with epidural anesthesia also, unless blood pressure is maintained with an agent such as ephedrine. When blood pressure is allowed to drop in a controlled fashion, hypotensive anesthesia is effected.