Epidural anesthesia prevents hypercoagulation in patients undergoing majororthopedic surgery

Background and Objectives: Epidural anesthesia (EA) is known to reduce post operative thromboembolic complications, hut mechanisms are incompletely und erstood. In this study, we tested the hypothesis that local anesthetics (LA ) prevent postoperative hypercoagulability without affecting physiologic ag gregation and coagulation processes. Methods: Clot signature analysis (CSA) was used to assess platelet and clot ting function. Venous blued samples were collected pre- and postoperatively from 41 patients undergoing major orthopedic surgery. The effect of surger y on 3 CSA parameters (platelet-mediated hemostasis time [PHT], clotting ti me [CT], and collagen-induced thrombus formation [CITF]) was determined in patients receiving EA (n = 20) and those receiving general anesthesia (GA) (n = 21). Results: In the GA group, orthopedic surgery induced a hypercoagulable stat e: PHT was reduced by 39% +/- 8.6% (P < .001), CT by 21% +/- 3.3% (P < .001 ), CITF by 10.3% <plus/minus> 5.9% (P = .06) compared with respective basel ine values. In the EA group, by contrast, no parameter was altered signific antly, bur PHT showed a tendency towards prolongation by 33.2% +/- 15.4% (P = .25). CT changed by 0% +/- 4.4% (P = .89), CITF by 3.8% +/- 7% (P = .78) . Conclusions: Use of EA prevents immediate postoperative hypercoagulability without affecting physiologic aggregation and coagulation processes. Also, CSA appears useful in predicting hypercoagulability and detecting platelet dysfunction.