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

Primary Aim: To determine if there is an optimal scanning technique for ultrasound-guided perineural catheter insertion that will result in the most accurate tip placement in proximity to the target nerve or plexus.

Secondary Aim: To determine if there is an optimal location for ultrasound-guided perineural catheter insertion along a target nerve or plexus that will result in maximum local anesthetic infusion benefits.

Inclusion criteria

• At least 18 years of age;
• Undergoing unilateral, upper (at or distal to the elbow) or lower (hip or distal) extremity orthopedic surgery, with moderate-to-severe postoperative pain expected; and
• Desiring a continuous perineural catheter for postoperative analgesia.

Exclusion criteria

• Patients who will have difficulty understanding the study protocol or caring for the infusion pump/catheter system; or
• Patients with any known contraindication to study medications, insulin-dependent diabetes mellitus, neuropathy of any etiology in the affected extremity;
• Patients with a contraindication to regional blockade (eg, clotting deficiency);
• Patients with any known acute or chronic hepatic or renal insufficiency or failure;
• Patients with any additional surgical site outside of the catheter-affected area (eg, iliac crest bone graft in addition to hand surgery);
• Patients with chronic opioid use (defined as daily use for more than 4 weeks prior to surgery) or active illicit substance abuse;
• Patient weighing < 40 kg;
• Pregnancy;
• Incarceration; or
• Inability to communicate with the investigators and hospital staff.