Oral anticoagulants and regional anesthesia: A perspective

Anesthesiologists often encounter anticoagulated patients in two clinical settings: patients with medical conditions requiring chronic anticoagulation and patients receiving perioperative thromboembolism prophylaxis. In the United Slates, warfarin is the most commonly used oral anticoagulant and is the focus of this study. The use of neuraxial block in patients receiving warfarin, either chronically or for perioperative thromboembolism prophylaxis, is nor a new issue. Although the preponderance of evidence suggests that as a specialty we have learned to safely practice regional anesthesia in these patient populations, we seek to emphasize the unknown. The actual incidence of complications from combining neuraxial blocks with warfarin therapy is unknown. We believe the numerator, the number of complications associated with neuraxial block and warfarin therapy, is probably underreported. The denominator, the number of neuraxial blocks placed in patients receiving or recently discontinued from warfarin therapy, is probably high but not well documented. This report will focus on the pharmacology of warfarin, how its anticoagulant effect is measured, and how that impacts the practice of regional anesthesia and analgesia.