Peripheral nerve blocks are routinely used and highly successful for intra-operative anesthesia and post-operative pain management. Nerve blocks are guided using either neurostimulation as a means to localize the right nerve or by ultrasound guidance or combining the 2 methods. The purpose of this study is to assess whether electrical stimulation improves nerve block quality, beyond its simple purpose of nerve localization.

The investigators wish to understand how electrical stimulation can affect local anesthetic disposition when performing a peripheral nerve block.

By studying this subject, the investigators open possibilities for improvement on many levels:

increasing the efficacy of the nerve block allows for a reduced onset time, reduced incidence of incomplete block and prolonged duration of the local anesthetics. This allows for patients to fully benefit from the analgesic properties of the nerve block, allows for a decrease in delays for the operating room readiness, and a decrease in the amount of medication needed for a successful nerve block. This will decrease side effects and risks of the nerve blocks. Overall better post-surgical pain control may decrease risks for developing chronic post-operative pain, a major post-operative complication.

The results of this study will open the door to novel approaches to manage acute post-operative pain.

Inclusion Criteria:

• Undergoing elective upper limb surgery with a planned brachial plexus nerve block

Exclusion Criteria:

• Under 18 years old
• ASA score above III
• Chronic pain condition with daily milligrams of morphine equivalent > 30
• Poorly controlled psychiatric condition
• Coagulopathy
• Active infection
• Moderate, severe or progressing neuropathy
• COPD/Chronic oxygen user
• Pregnancy
• Incarceration
• Unable to consent