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How To Do a Median Nerve Block
Equipment
Nonsterile gloves Barrier precautions as indicated (eg, face mask, safety glasses or face shield, cap and gown) Antiseptic solution (eg,chlorhexidine,povidone-iodine, alcohol) Injectable local anesthetic* such aslidocaine2% withepinephrine1:100,000, or for longer-duration anesthesia,bupivacaine0.5% withepinephrine† 1:200,000 Syringe (eg, 5 to 10 mL) and needle (eg, 25 or 27 gauge, 3.5 cm long) for anesthetic injection For ultrasonography:Ultrasound machine with high-frequency (eg, 7.5 MHz or higher) linear array probe (transducer); probe cover (eg, transparent sterile dressing, single-use probe cover); sterile, water-based lubricant, single-use packet (preferred over multi-use bottle of ultrasound gel) * Local anesthetics are discussed in Lacerations . † Maximum dose of local anesthetics:Lidocainewithoutepinephrine, 5 mg/kg;lidocainewithepinephrine, 7 mg/kg;bupivacaine, 1.5 mg/kg. NOTE: A 1% solution (of any substance) represents 10 mg/mL (1 g/100 mL).Epinephrinecauses vasoconstriction, which prolongs the anesthetic effect. Patients with cardiac disease should receive only limited amounts ofepinephrine(maximum 3.5 mL of solution containing 1:100,000epinephrine); alternatively, use local anesthetic withoutepinephrine. 