What is the recommended regimen and protocol for a walking epidural in an adult postoperative patient?

Walking Epidural Protocol for Postoperative Pain Management

Critical Clarification: "Walking Epidural" Terminology

The term "walking epidural" traditionally refers to labor analgesia using ultra-low concentration local anesthetic solutions that preserve motor function, not a standard postoperative pain management technique. For postoperative patients, the goal is effective analgesia with minimal motor block to facilitate early mobilization, but this differs from obstetric walking epidurals 1, 2.

Recommended Postoperative Epidural Regimen

Standard Infusion Protocol

For postoperative pain management in adults, use continuous epidural infusion of bupivacaine 0.1-0.125% (or ropivacaine 0.2%) combined with fentanyl 2-2.5 µg/mL at 6-14 mL/hour. 1, 3

• The maximum safe infusion rate is 14 mL/hour using these low-concentration solutions 1
• This combination provides superior analgesia compared to either agent alone while minimizing motor block 2, 4
• The addition of opioid reduces local anesthetic requirements and improves analgesia quality 5, 2

Catheter Placement and Coverage

Insert the epidural catheter at the spinal level corresponding to the surgical site: 6

• Mid-thoracic (T5-T8) for upper abdominal surgery 6
• T7-T10 for major abdominal procedures 6
• T10-L2 for lower abdominal/pelvic surgery 5

Verify sensory block using cold/pinprick testing before surgical incision and daily thereafter to ensure adequate coverage. 6, 5

Alternative Solution Options

If standard bupivacaine/fentanyl is unavailable or contraindicated:

• Ropivacaine 0.2% with fentanyl 2-2.5 µg/mL at 6-14 mL/hour 1, 3
• Sufentanil 0.75-1 µg/mL can replace fentanyl in equivalent infusion rates 1, 7
• For VATS specifically: ropivacaine 1.5 mg/mL with sufentanil 0.2 µg/mL at 5-10 mL/hour 1, 2

Duration of Therapy

Continue epidural infusion for 48-72 hours postoperatively, then transition to oral multimodal analgesia (acetaminophen, NSAIDs, oral opioids as needed) after a successful stop-test. 6

• Functioning catheters may be used longer if needed 6
• Cumulative doses up to 770 mg ropivacaine over 24 hours are well-tolerated 3
• Continuous infusions up to 72 hours have been safely used in adults 3

Hemodynamic Management

If hypotension occurs, confirm euvolemia first, then add vasopressors rather than administering excessive intravenous fluids. 6, 5

• Hypotension results from sympathetic blockade, not necessarily hypovolemia 6
• Signs of true hypovolemia include tachycardia, sweating, confusion, and decreased capillary refill 6
• Monitor blood pressure every 5 minutes for at least 15 minutes following loading doses or boluses 5, 2

Monitoring Requirements

Essential monitoring parameters include: 5, 2

• Motor block assessment using Bromage score hourly during infusion 5
• Sensory level testing daily (or more frequently) to ensure adequate coverage 6
• Vital signs including blood pressure, heart rate, respiratory rate, and oxygen saturation 2
• Signs of local anesthetic systemic toxicity (blurred vision, dizziness, tinnitus, perioral numbness, tongue paresthesia) 6, 2

Breakthrough Pain Management

If patients require 2 bolus doses within one hour, double the baseline infusion rate to maintain adequate analgesia. 2

• Standard bolus dosing: 5 mL every 40 minutes for VATS protocols 1
• Adjust infusion to provide sufficient analgesia for mobilization out of bed 6

Common Pitfalls and Prevention

Up to 33% of epidural catheters may fail due to: 6, 2

• Incorrect catheter placement outside the epidural space
• Inadequate dermatomal coverage of the surgical incision
• Insufficient local anesthetic/opioid dosing
• Pump malfunction

Prevention strategies:

• Verify catheter placement with test dose before induction 3
• Confirm sensory block covers surgical dermatomes before incision 6, 5
• Use only preservative-free formulations for neuraxial administration 5, 3
• Ensure adequate postoperative expertise in epidural management is available 6

Contraindications to Postoperative Epidural

Do not use epidural analgesia for minimally invasive surgery (MIS/laparoscopic procedures) - alternative techniques (spinal analgesia, TAP blocks, IV lidocaine) are more appropriate 6

• Epidurals provide no benefit over less invasive alternatives in MIS 6
• The risks of hypotension, urinary retention, and motor block outweigh benefits for minimally invasive approaches 6

Special Considerations

For patients with cardiopulmonary risk factors, epidural analgesia is particularly beneficial as it decreases cardiopulmonary morbidity and improves pulmonary function. 2

In opioid-tolerant patients, consider adding clonidine 1-2 µg/kg to the local anesthetic for prolonged analgesia and reduced opioid requirements. 2