Oral anticoagulants and regional anesthesia: A perspective

Anesthesiologists often encounter anticoagulated patients in two clinical s ettings: patients with medical conditions requiring chronic anticoagulation and patients receiving perioperative thromboembolism prophylaxis. In the U nited Slates, warfarin is the most commonly used oral anticoagulant and is the focus of this study. The use of neuraxial block in patients receiving w arfarin, either chronically or for perioperative thromboembolism prophylaxi s, is nor a new issue. Although the preponderance of evidence suggests that as a specialty we have learned to safely practice regional anesthesia in t hese patient populations, we seek to emphasize the unknown. The actual inci dence of complications from combining neuraxial blocks with warfarin therap y is unknown. We believe the numerator, the number of complications associa ted with neuraxial block and warfarin therapy, is probably underreported. T he denominator, the number of neuraxial blocks placed in patients receiving or recently discontinued from warfarin therapy, is probably high but not w ell 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.