Minimum Effective Volume of Lidocaine Costoclavicular Brachial Plexus Block

Inclusion Criteria:

• age between 18 and 70 years
• American Society of Anesthesiologists classification 1-3
• body mass index between 20 and 30

Exclusion Criteria:

• adults who are unable to give their own consent
• pre-existing neuropathy (assessed by history and physical examination)
• coagulopathy (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. platelets≤ 100, International Normalized Ratio≥ 1.4 or partial prothrombin time ≥ 50)
• renal failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. creatinine≥ 100)
• hepatic failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. transaminases≥ 100)
• allergy to local anesthetics
• pregnancy
• prior surgery in the infraclavicular region
• chronic pain syndromes requiring opioid intake at home