Letters to the Editor: Letters & Announcements
To the Editor:
There is very little information concerning the performance of epidural blood patches on patients receiving enoxaparin (Lovenox™; Aventis Pharmaceuticals, Somerville, NJ) with regard to the safety of the intervention as well as the effectiveness of the blood patch. We present a case in which a successful epidural blood patch was performed in a female patient taking 1.3 mg/kg of enoxaparin twice daily, 30 h after the last dose was given.
A 39-yr-old female taking enoxaparin, 100 mg orally twice a day, underwent an uneventful lumbar puncture by her neurologist to exclude pseudotumor cerebri. Soon afterwards the patient developed a debilitating headache in the occipital region that became excruciating in the upright position. Her history was significant for deep venous thrombosis (DVT). The patient was treated with IV hydration and IV caffeine for 24 h without relief. Thirty hours after the last dose of enoxaparin, an epidural blood patch was performed with 20 mL of autologous blood with complete resolution of her postural headache.
Low molecular weight heparinoids (LMWH) are increasingly prescribed for systemic anticoagulation therapy and DVT treatment and prophylaxis (1–3). Gaiser et al. (4) reported a partially successful epidural blood patch in a female patient 24 h after 190 mg of LMWH administered subcutaneously. There appears to be a predictable and reproducible dose response to enoxaparin when dosed on a weight-adjusted basis in small doses for thromboprophylaxis (5). With the lack of predictability at larger doses pharmacokinetic simulation is extremely difficult.
The terminal half-life of plasma anti-Xa activity of enoxaparin is between 3–4 h. Therefore, we elected to wait for more than 7 half-lives to perform an epidural blood patch. To our knowledge, a successful epidural blood patch on a patient receiving enoxaparin more than 1.5 mg/kg/day has not been reported.
Nalini Vadivelu, MD
Craig Freiberg, MD
James Kim, MD
Mathew Wallace, MD
Raymond Sinatra, MD, PhD
Department of Anesthesiology
Yale University School of Medicine
New Haven, CT
1. Horlocker TT, Wedel DJ, Benzon H, et al. Regional anesthesia in the anticoagulated patient: defining the risks (the second ASRA Consensus Conference on Neuraxial Anesthesia and Anticoagulation). Reg Anesth Pain Med 2003;28:172–97.
2. Horlocker TT, Wedel DJ. Neuraxial block and low-molecular-weight heparin: balancing perioperative analgesia and thromboprophylaxis. Reg Anesth Pain Med 1998;23:164–77.
3. Horlocker TT, Heit JA. Low molecular weight heparin: biochemistry, pharmacology, perioperative prophylaxis regimens, and guidelines for regional anesthetic management. Anesth Analg 1997;85:874–85.
4. Gaiser RR, Mauney DL, Imbesi SG. Epidural blood patch in a patient with an arachnoid cyst. J Clin Anesth 2002;14:42–5.
5. Yin B, Barratt SM, Power I, Percy J. Epidural haematoma after removal of an epidural catheter in a patient receiving high-dose enoxaparin. Br J Anaesth 1999;82:288–90.