POSTOPERATIVE EPIDURAL ANALGESIA AND ORAL ANTICOAGULANT-THERAPY

The relative safety of epidural catheter placement with subsequent hep arinization has been well documented. However, what is the risk of neu rologic sequelae in such patients who receive warfarin perioperatively ? This study retrospectively evaluates the risk of spinal hematoma in patients receiving postoperative epidural analgesia while receiving lo w-dose warfarin after total knee replacement. All patients received lo w-dose warfarin to prolong the prothrombin time (PT) to 15.0-17.3 s (n ormal 10.9-12.8 s). There were 192 epidural catheters placed in 188 pa tients. All catheters were advanced through an 18-gauge needle. In 13 instances, blood was noted during needle and/or catheter placement. In addition to warfarin, 36 patients with indwelling catheters received nonsteroidal antiinflammatory drugs (NSAIDs). Epidural catheters were left indwelling 37.5 +/- 15 h (range-13-96 h). The mean PT was not inc reased beyond the normal range until the third postoperative day and d id not reach 15 s until the seventh postoperative day. Cumulative warf arin dose at that time was 20.0 +/- 7.6 mg. Mean PT at the time of epi dural catheter removal was 13.4 +/- 2 s. There were no signs of spinal hematoma. Although epidural catheter placement and subsequent anticoa gulation with warfarin appears relatively safe, there is a large varia bility in patient response to warfarin; therefore, coagulation status should be monitored to avoid excessive prolongation of the PT, and the patient should be watched closely for evidence of spinal hematoma.