Clinical volume of patients for recruitment stopped.

Pain Clinic patients undergoing physiotherapy for rehabilitation often have arm freezing performed. The quality of physiotherapy is felt to be superior with good pain control. The quality of the freezing is felt to be better when it is done with ultrasound guidance. We are able to use less drug to achieve the same result. For this reason, we are doing a study to look at the level of freezing drug that accumulates in the body. We feel that the drug levels will be significantly different. We also feel that the time-to-peak drug level will be different than with traditional arm freezing procedures.

Inclusion Criteria:

• patients undergoing brachial plexus anesthesia as part of disease management who have consented to participate in the study

Exclusion Criteria:

• Contraindication to brachial plexus anesthesia
• Informed consent not obtained