What is the best approach to anesthesia and pain management for an opioid-tolerant patient on regular oral hydromorphone (Hydromorphone) undergoing a procedure where epidural anesthesia is not appropriate and rectal sheath catheters are used?

Multimodal Anesthesia Management for Opioid-Tolerant Patients with Rectal Sheath Catheters

For opioid-tolerant patients undergoing surgery where epidural anesthesia is contraindicated, a multimodal approach using continuous rectus sheath catheters combined with adjuvant medications offers optimal pain control while minimizing additional opioid requirements.

Preoperative Considerations

• Assess baseline opioid requirements: Document current hydromorphone dosing regimen and convert to IV equivalent for perioperative management
• Continue baseline opioid: Maintain the patient's regular oral hydromorphone dosing up to the day of surgery to prevent withdrawal 1
• Preoperative adjuncts:
  • Administer dexamethasone 0.1-0.2 mg/kg IV (maximum 8mg) to reduce postoperative swelling and inflammation 2, 3
  • Consider gabapentin 300-600mg PO preoperatively for neuropathic pain modulation

Intraoperative Management

1. General anesthesia with multimodal adjuncts:

   • Standard induction with propofol, muscle relaxant, and airway management
   • Opioid-sparing adjuncts:
     • IV lidocaine infusion (1.5 mg/kg bolus followed by 1-2 mg/kg/hr) 2, 3
     • IV ketamine (0.25-0.5 mg/kg bolus followed by 0.1-0.25 mg/kg/hr infusion) 3
     • Alpha-2 agonist (dexmedetomidine 0.2-0.7 mcg/kg/hr or clonidine) 3
     • IV acetaminophen 1g and IV NSAID (ketorolac 15-30mg) 2

2. Rectus sheath catheter placement:

   • Surgeon-placed bilateral rectus sheath catheters under direct visualization
   • Initial bolus of long-acting local anesthetic (ropivacaine 0.5% or bupivacaine 0.25%, 10-15ml per side)
   • Consider adding clonidine 1-2 mcg/kg to local anesthetic mixture for prolonged effect 4

Postoperative Pain Management

Immediate Postoperative Period (PACU)

1. Continuous local anesthetic infusion:

   • Start bilateral rectus sheath catheter infusion with ropivacaine 0.2% at 5-8 ml/hr per catheter 4
   • Bolus option for breakthrough pain (5ml of 0.2% ropivacaine per catheter)

2. Systemic medications:

   • Continue IV lidocaine infusion (1-1.5 mg/kg/hr) for first 24-48 hours if no contraindications 2
   • IV acetaminophen 1g every 6 hours
   • IV ketorolac 15-30mg every 6 hours (maximum 48 hours) then transition to oral NSAID 2
   • Continue baseline opioid requirements with IV hydromorphone PCA for breakthrough pain

Ward Management

1. Multimodal non-opioid analgesia:

   • Continue rectus sheath catheter infusion for 3-5 days
   • Transition to oral acetaminophen 1g every 6 hours
   • Transition to oral NSAID (ibuprofen 600mg every 6 hours or equivalent)
   • Gabapentin 300mg TID or pregabalin 75mg BID

2. Opioid management:

   • Return to patient's baseline oral hydromorphone regimen as soon as oral intake is established 2, 1
   • Avoid increasing baseline opioid dose unless absolutely necessary
   • If additional opioid needed, use immediate-release formulations with close monitoring of sedation and respiratory status 2

Monitoring and Safety

• Assess pain scores at rest and with movement/coughing
• Monitor sedation level using a standardized scale (0-3) alongside respiratory rate
• Daily assessment of rectus sheath catheter sites for infection or displacement
• Daily functional assessment using functional activity score (A: no limitation, B: mild limitation, C: unable to complete activity due to pain) 2

Discharge Planning

• Taper adjuvant medications (gabapentinoids, NSAIDs) before opioids 2
• Return to pre-surgical opioid regimen without dose escalation if possible
• Clear tapering plan if opioid requirements have increased
• Involve pain management service for complex cases

Potential Pitfalls and Caveats

• Rectus sheath catheters only provide somatic pain relief for midline incisions; may not adequately control visceral pain
• Local anesthetic systemic toxicity risk with bilateral catheters; monitor for signs (perioral numbness, metallic taste, seizures)
• Opioid-induced hyperalgesia may occur in opioid-tolerant patients; ketamine can help mitigate this effect
• Avoid modified-release opioid preparations in the immediate postoperative period due to risk of respiratory depression 2

This approach provides effective analgesia while minimizing additional opioid exposure, facilitating earlier mobilization, and potentially reducing postoperative complications in opioid-tolerant patients.