2019 FSA Posters

P013: NEURAXIAL TECHNIQUES IN THE SETTING OF HEPARIN-INDUCED THROMBOCYTOPENIA AND FONDAPARINUX
James R Brown, DO, Brandon Beck, MD; University of Florida, Gainesville

Introduction: Fondaparinux is a new antithrombotic in the Xa inhibitor category. It is often used in patient populations with heparin-induced thrombocytopenia (HIT). Given its sustained and irreversible antithrombotic effect, there are no suggested guidelines for the administration of this medication and timing of a neuraxial intervention, and should even be avoided when a neuraxial catheter is already in place. It can be theorized that, with a half-life of 21 hours, neuraxial procedures would be safe after five half-lives, or 105 hours.

Case Presentation: 77 year old male presented for aortic arch aneurysm repair. A lumbar drain was requested for the procedure, to be placed preoperatively by the acute pain service. There were no contraindications to placement, and the procedure was uneventful with expected results. The surgery was unremarkable and without complications. On post-operative day (POD) 3, the lumbar drain developed a clot, which occluded the drain. Preparations were made for the drain to be removed; however, platelet levels were beginning to decline. On POD 4, heparin was discontinued with suspicion for HIT, and labs were sent for confirmation. Given the patient’s many comorbidities, the ICU team decided upon fondaparinux for anticoagulation. Upon recognizing this incident, the acute pain service discontinued the medication; however, the patient had already received 2 doses. With the recent administration of fondaparinux and the continued downward trend of platelets to a low of 37000, it was deemed unsafe for lumbar drain removal. However, the patient soon became febrile with an up-trending white blood cell (WBC) count. Broad spectrum antibiotics were started and the patient was pan-cultured. CSF was unable to be sent as the lumbar drain was occluded. No obvious source of infection could be immediately identified. A thromboelastogram showed depressed platelet function. And although there was a slight decrease in WBC count by POD 6, it was only temporary as it continued to rise by POD 7 to 18800. Platelet levels began to recover and were at 81000 on POD 7. With the renewed incline in his platelet levels combined with the possible infection risk, the decision to remove the lumbar drain was made. The patient had been given DDAVP in preparation for a bedside procedure with the ICU team, so the spinal drain was removed shortly after administration. On follow-up at 24 and 48 hours, the patient had no signs or symptoms of epidural hematoma and maintained an appropriate neurological exam.

Discussion: This case demonstrates the need for guidelines for the newer anticoagulants. Also, it demonstrated the complex nature of neuraxial procedures and anticoagulants in the setting of heparin-induced thrombocytopenia. Although no set guidelines are found in available literature, a half-life of 21 hours for fondaparinux suggests that safe removal would be 105 hours after the last dose, approximately 5 half-lives. As the risk of the sepsis outweighed the risk of epidural hematoma on POD 7, the decision was made to remove the catheter with the hope that no adverse outcome would result.