November-December 1998-Volume 23, Number 6- Supplement 2

  Supplement to Regional Anesthesia and Pain Medicine

  Neuraxial Anesthesia and Anticoagulation

  Official Publication of the American, European, Asian and Oceanic, and Latin American Societies of Regional Anesthesia

  Regional Anesthesia and Pain Medicine 23(6) Supp 2: 134-177, 1998

  Neuraxial Block and Low-Molecular-Weight Heparin : Balancing Perioperative Analgesia and Thromboprophylaxis

  Terese T Horlocker, MD., and Denise J. Wedel, MD.

Recommendations for Patients Receiving LMWH and Neuraxial Anesthesia

The decision to perform a neuraxial block on a patient receiving perioperative LMWH must be made on an individual basis by weighing the risk of spinal hematoma with the benefits of regional anesthesia for a specific patient. Anesthesiologists in the United States can draw on the European experience to develop their own practice guidelines for the management of patients undergoing spinal and epidural blocks while receiving perioperative LMWH. Although it is impossible to devise recommendations that will completely e1iminate the risk of spinal hematoma, we believe:

1. Monitoring of anti-Xa level is not recommended. The anti-Xa level is not predictive of the risk of bleeding and is, therefore, not helpful in the management of patients undergoing neuraxial blocks.

2. Antiplatelet or oral anticoagulant medications administered in combination with LMWH may increase the risk of hemorrhagic complications perioperatively, including hematoma. Education of the entire patient care team is necessary to avoid potentiation of the anticoagulant effects.

3. Presence of blood during needle and catheter placement does not necessitate postponement of surgery. However, initiation of LMWH therapy in this setting should be delayed for 24 hours postoperatively. Traumatic needle or catheter placement may signa1 an increased risk of spinal hematoma, and it is recommended that this consideration be discussed with the surgeon.

4. Patients on preoperative LMWH can be assumed to have altered coagulation. A single-dose spinal anesthetic may be the safest neuraxial technique in patients receiving preoperative LMWH. In these patients, needle placement should occur at least 10 to 12 hours after the LMWH dose, whereas patients receiving higher doses of LMWH (e.g., enoxaparin 1 mg/kg twice daily) will require longer delays (24 hours). Neuraxial techniques should be avoided in patients administered a dose of LMWH 2 hours preoperatively (general surgery patients), because needle placement would occur during peak anticoagulant activity.

5. Patients with postoperative initiation of LMWH thromboprophylaxis may safely undergo single-dose and continuous catheter techniques. The first dose of LMWH should be administered no earlier than 24 hours postoperatively and only in the presence of adequate hemostasis. In addition, it is recommended that indwelling catheters be removed before initiation of LMWH thromboprophylaxis. If a continuous technique is selected, the epidural catheter may be left indwelling overnight and removed the following day, with the first dose of LMWH administered 2 hours after catheter removal.

6. The decision to implement LMWH thromboprophylaxis in the presence of an indwelling catheter must be made with care. Extreme vigilance of the patient’s neurological status is warranted. An opioid or dilute local anesthetic solution is recommended in these patients to allow frequent monitoring of neurological function. If epidural analgesia is anticipated to continue for more than 24 hours, LMWH administration may be selected (e.g., external pneumatic compression), based on the risk profile for the individual patient. These decisions should be made preoperatively to allow optimal management of both postoperative analgesia and thromboprophylaxis.

7. For any LMWH prophylaxis regimen, the timing of catheter removal is of paramount importance Catheter removal should be delayed for at least 10 to 12 hours after a dose of LMHW A true normalization of the patient’s coagulation status could be achieved if the evening dose of LMWH was not given and the catheter was removed the following morning (24 hours after the last dose). Again subsequent dosing should not occur for at least 2 hours after catheter removal.