Warfarin.
Chronic warfarin therapy increases the risk of spinal hematoma following lumbar puncture. The addition of agents that affect different parts of the clotting mechanism likely increase the risk for spinal hematoma and do so without further elevation of the prothrombin time (PT) or international normalized ratio (INR).9 These medications include heparin, nonsteroidal anti-inflammatory drugs (NSAIDs), and antiplatelet agents. Warfarin should be discontinued in anticipation of the spinal procedure and normalization of the INR documented preprocedure. If a spinal procedure is performed on a patient with an INR >1.2, close neurologic testing of motor and sensory function should be performed for at least 24 hours to ensure prompt recognition and treatment of spinal hematoma.
In emergent cases, the injection of vitamin K or transfusion of fresh frozen plasma may counteract the effects of warfarin.
Heparin.
There is no contraindication to spinal puncture in patients receiving subcutaneous heparin as a prophylaxis for deep venous thrombosis providing the total dose is <10,000 U.11 Higher dosing may result in sustained prolongation of the activated partial thromboplastin time (aPTT). These patients are managed similar to those who are systemically heparinized. Delaying the scheduled heparin injection until after the puncture may reduce the risk of spinal hematoma. The risk of bleeding is likely increased in debilitated patients on prolonged therapy. Patients receiving heparin for longer than 4 days need to have a platelet count assessment because of the potential for heparin-induced thrombocytopenia.12
Systemic heparinization represents an increased risk for spinal bleeding.8 Heparin infusion should be discontinued and aPTT normalized before the procedure. A subsequent dose of intravenous heparin should not be administered for at least an hour after the procedure.11,13 The combined use of other anticoagulants with unfractionated heparin may increase the risk of spinal hematoma. These include antiplatelets, low-molecular-weight heparin (LMWH), and oral anticoagulants.
LMWH.
LMWH is the recommended thromboprophylactic agent following major orthopedic and general surgical procedures.14 It is important that there be a number of dosing regimens for LMWH, including low-dose (thromboprophylactic) and high-dose (therapeutic) applications. There are many pharmacologic differences between standard unfractionated heparin and LMWH, including prolonged half-life and irreversibility with protamine.15,16 Early postoperative dosing, twice-daily dosing, and traumatic needle placement were identified as risk factors for spinal hematoma associated with neuraxial anesthesia. Because significant anticoagulant activity persists for 12 hours after low-dose injection (and 24 hours for a high-dose injection), these time intervals should be observed before a spinal procedure. Likewise, the first postprocedural LMWH dose should be administered 18?24 hours later, to allow for adequate hemostasis.
http://www.ajnr.org/cgi/content/full/27/3/468
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