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

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.