Study objectives: To study whether a human recombinant formulation of hyaluronidase (rHuPH20, available as Hylenex®, Baxter Corp.) facilitates local anesthetic spread in axillary plexus blocks. Design: Randomized controlled trial. Setting: The pre-operative care area of an ambulatory surgery center. Patients: 59 adult patients, ASA status I -IV, undergoing surgery of the elbow, forearm or hand. Interventions: Patients were allocated to receive a single-injection axillary brachial plexus block

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... th (n=31) or without (n=28) the addition of 150 Units rHuPH20 (volume=1 ml, cost=$150.00) to a local anesthetic solution of bupivacaine 2.5 mg/ml, lidocaine 10 mg/ml and epinephrine 3 mcg/ml. Measurements: A composite score of sensory and motor examination at 20 minutes post-injection (0-16 points). Block success was defined as a minimal composite score of 14 points. Main results: Overall success rate was 39% in the control group and 29% in the treatment group. The mean composite score per patient was 11.9 (95%CI: 10.7-13.0) in the control group and 11.7 (95%CI: 11.0-12.4) in the treatment group. None of these differences were statistically significant. Conclusions: Block success rates for single-injection axillary plexus block were unaffected by the addition of 150U rHuPH20.