International normalized ratio and prothrombin time values before the removal of a lumbar plexus catheter in patients receiving warfarin after total hip replacement.

Abstract

There is a paucity of data regarding the coagulation status when discontinuing perineural catheters in patients receiving anticoagulant after operation. This retrospective study was designed to establish international normalized ratio (INR) and prothrombin time (PT) at the time of removal of lumbar plexus perineural catheters in patients receiving warfarin after total hip replacement. Patients who received a continuous lumbar plexus nerve block for postoperative analgesia and received warfarin after total hip surgery between August 2002 and June 2007 were included in this retrospective study. PT and INRs were recorded before surgery and every day after operation along with any post-surgical nerve injury and bleeding related to the removal of the perineural catheter. Six hundred and seventy patients met the inclusion criteria. Almost all lumbar plexus catheters (89%) were removed on postoperative day 2. At the time of the perineural catheter removal, 36.2% of patients had an INR >1.4 (range: 1.5-3.9). One case of local bleeding was recorded at the time of the catheter removal with an INR of 3.0. This was managed with a direct pressure at the site. Although in this retrospective analysis, we demonstrated that lumbar plexus catheters were removed with an INR > or =1.5, additional data are required to confirm the safety of such an approach.