Infraclavicular brachial plexus block has been used more frequently with the development of high-resolution ultrasound. Compared with peripheral nerve block using landmark technique or nerve stimulator technique, ultrasound-guided peripheral nerve block decreases the required dose of local anesthetics. As the dose of the drug used decreases, the systemic toxic effects of local anesthetics are reduced. However, the decreased dose of the drugs might have influence on the onset time of local anesthetics. Thus, the investigator aimed to evaluated the onset time of the two equipotent local anesthetics, 0.375% ropivacaine and 0.25% levobupivacaine.

Inclusion Criteria:

• American Society of Anesthesiologists physical status 1-3
• Patients undergoing upper extremity surgery with infraclavicular brachial plexus block

Exclusion Criteria:

• Patients who do not agree to participate in clinical trial
• Patients presenting with neurological deficits of the upper arm, severe coagulopathy, chronic renal failure, cardiopulmonary compromise, cerebral vascular disease, hypersensitivity to hyaluronidase or local anesthetics or local infection at the site of the infraclavicular block, pregnancy