Safety of Multiple, Simultaneous Continuous Peripheral Nerve Block Catheters in a Patient Receiving Therapeutic Low-Molecular-Weight Heparin

Abstract

The application of continuous peripheral nerve block (CPNB) has been an important anesthetic tool in the management of combat soldiers wounded from current conflicts. Placing and maintaining CPNBs becomes a challenge in this patient population due to concomitant prophylactic and therapeutic anticoagulation. A 32-year-old male sustained multiple traumatic injuries from an improvised explosive device, including a right tibial fracture, a left tibial fracture, and a left ulnar fracture. His pain was originally well controlled with a left infraclavicular CPNB (0.2% ropivacaine at 10 mL/h with 3 mL bolus every 20 minutes) and an epidural (0.2% ropivacaine at 10 mL/h with 5 mL bolus every 30 minutes). He subsequently developed a common femoral vein thrombus and was treated with low-molecular-weight heparin. His epidural catheter was discontinued; however, his pain was not well controlled with intravenous and oral pain medication. We elected to place bilateral, tunneled sciatic CPNBs and a left, tunneled femoral CPNB. We started infusions of 0.2% ropivacaine at 10 mL/h in each catheter, in addition to 5 mL every 30 minutes demand dose in each sciatic catheter. The patient's serum ropivacaine levels were analyzed 24 hours after the start of the infusions and were found to be 5.8 mg/L and <0.1 mg/L for total and free concentrations, respectively. This case highlights the application of simultaneous CPNB techniques in a patient with multiple extremity injuries receiving anticoagulant therapy.