Anticoagulants and Peripheral Nerve Block

Case Synopsis

A 70-year-old man with a history of valvular heart disease, peripheral vascular disease, and diabetes mellitus is scheduled to undergo a below-the-knee amputation. The patient has been receiving daily anticoagulation with warfarin since his aortic valve replacement 5 years ago. Five days before surgery, the patient’s warfarin was discontinued by his primary care physician, at which time he began therapeutic anticoagulation bridging therapy with low-molecular-weight heparin (LMWH). The patient’s last injection of LMWH was 24 hours ago. The orthopedic surgeon intends to reinitiate anticoagulation with LMWH 12 hours after surgery. During the preanesthetic interview, the patient requests peripheral nerve catheters for extended postoperative analgesia.