Optimizing Catheter Insertion Technique for Ultrasound-guided Continuous Peripheral Nerve Blocks

Subjects assigned to this group will have their perineural catheter placed in a proximal position (higher up in the arm or leg) with ultrasound guidance. The onset time of sensory anesthesia will be measured following local anesthetic bolus via the catheter.

Subjects assigned to this group will have the target nerve or plexus identified in short axis (cross-section) using ultrasound. Perineural catheter insertion will be performed in-plane. The onset time of sensory anesthesia will be measured following local anesthetic bolus via the catheter.

Subjects assigned to this group will have the target nerve or plexus identified in long axis (longitudinal) using ultrasound. Perineural catheter insertion will be performed in-plane. The onset time of sensory anesthesia will be measured following local anesthetic bolus via the catheter.

Subjects assigned to this group will have their perineural catheter placed in a distal position (further down in the arm or leg) with ultrasound guidance. The onset time of sensory anesthesia will be measured following local anesthetic bolus via the catheter.