Continuous Infusions vs Scheduled Bolus Infusions

Regional anesthetic techniques are an integral part to many anesthetic approaches, providing both intraoperative and postoperative anesthesia and analgesia. Regional anesthesia peripheral nerve blocks have been shown to reduce postoperative pain and improve measures such as opioid requirements and readiness for discharge. By using a catheter technique for continuous peripheral nerve blocks, analgesia can be extended well into post-operative days 2 and 3, further extending these benefits. Historically these catheters have implemented a continuous dosing regimen of local anesthetic, but increasingly there is evidence of improved analgesic outcomes without adverse effects by using a scheduled bolus dosing regimen. Many institutions have implemented this new protocol for catheter dosing. The beneficial effect of scheduled bolus dosing has not been studied in all blocks and all surgical procedures.

The study will consist of three independent arms, each designed to evaluate a different nerve block site: interscalene, adductor canal, and infraclavicular. A total of 60 patients will be enrolled in each arm.

Inclusion criteria

• Adult patients presenting for nerve block catheters for post-operative analgesia
• ASA physical status I, II, or III.

Exclusion criteria

• Pregnancy
• Incarceration
• Age <18
• BMI >35
• Pre-operative opioid use >30 mg morphine equivalents per day
• Inability to communicate with investigators by telephone
• Pre-existing neuropathy of the operative extremity.