How should rebound pain after regional anesthesia be anticipated and managed in adult surgical patients?

Managing Rebound Pain After Regional Anesthesia

Patients must receive scheduled multimodal analgesia—specifically paracetamol (acetaminophen) plus an NSAID or COX-2 inhibitor—starting before the regional block wears off, combined with intravenous dexamethasone 8 mg at induction, to prevent the severe rebound pain that affects up to 61.7% of patients when peripheral nerve blocks resolve. 1, 2

Understanding Rebound Pain

Rebound pain is characterized by severe, excruciating pain that develops within 24 hours after peripheral nerve block resolution, representing a transition from well-controlled pain during the block to intense hyperalgesia afterward. 3, 2 This phenomenon affects approximately 50-61.7% of patients receiving peripheral nerve blocks, with half experiencing severe pain (pain scores >7/10). 2, 4

Core Prevention Strategy: Multimodal Analgesia Before Block Resolution

Essential Components (Start Preoperatively or Intraoperatively)

• Paracetamol (acetaminophen): Administer regularly throughout the perioperative period, continuing into the postoperative phase. 1
• NSAID or COX-2 inhibitor: Give in combination with paracetamol unless contraindicated (avoid with therapeutic anticoagulation or liver disease). 1, 5
• Intravenous dexamethasone 8 mg at induction: This single dose prolongs block duration, reduces supplemental analgesic requirements, and independently reduces rebound pain risk. 1, 2

Critical timing principle: These medications must be administered before the block wears off—waiting until pain returns negates the preventive benefit. 1, 6

High-Risk Patient Identification

Patients at increased risk for rebound pain include:

• Younger age and female gender: Both independently associated with higher rebound pain incidence. 4
• Preoperative pain present: Patients with existing pain before surgery have 3.9 times higher odds of rebound pain. 2
• Bone/orthopedic surgery: Type of surgery significantly impacts risk (6.5 times higher odds). 2
• Absence of IV dexamethasone: Patients not receiving preoperative dexamethasone have 2.6 times higher rebound pain risk. 2

Procedure-Specific Considerations

For Shoulder Surgery (Rotator Cuff Repair)

• Continuous interscalene block is superior to single-shot: Single-shot blocks provide only 6-8 hours of analgesia with documented rebound pain at 24 hours. 1
• If single-shot block used: Scheduled paracetamol plus NSAID/COX-2 inhibitor is imperative to prevent severe pain escalation when the block resolves. 1
• Alternative if interscalene unavailable: Axillary nerve block with or without suprascapular nerve block. 1

For Thoracic Surgery (VATS)

• Paravertebral block or erector spinae plane (ESP) block should be strongly considered as part of multimodal analgesia. 1
• Serratus anterior plane block can effectively reduce pain when combined with systemic analgesics. 1

For Abdominal Surgery

• Transversus abdominis plane (TAP) block or rectus sheath block provides opioid-sparing effects when combined with scheduled non-opioids. 1
• Continuous local wound infusion catheters consistently reduce pain scores and opioid requirements without increasing infection risk. 1

Additional Adjunctive Strategies

Perineural Adjuvants

• Preservative-free dexmedetomidine added to local anesthetic solutions prolongs block duration. 1
• Perineural dexamethasone: While studied, intravenous dexamethasone is recommended over perineural administration for equivalent benefit with better safety profile. 1, 6

Intraoperative Adjuncts

• Intravenous lidocaine infusion (1-2 mg/kg bolus, then 1-2 mg/kg/h) provides analgesic and anti-hyperalgesic effects when regional anesthesia alone is insufficient. 7, 5
• Ketamine 0.5 mg/kg IV may be added for patients at high risk of severe pain or those on chronic opioid therapy. 7

Rescue Analgesia Protocol

When rebound pain occurs despite preventive measures:

• First-line rescue: Nalbuphine 0.1-0.2 mg/kg IV, titrated to effect, repeated every 3-4 hours as needed. 7
• Alternative opioids: Intravenous fentanyl or morphine with appropriate monitoring. 1
• Maintain scheduled non-opioids: Continue paracetamol and NSAIDs even when adding rescue opioids. 5

Patient Education: Non-Negotiable Component

Patients must be counseled preoperatively about the expected timeline of block resolution and the possibility of rebound pain. 3, 6 This education should include:

• When the block will likely wear off (typically 12-24 hours for single-shot blocks). 1
• Instructions to take scheduled analgesics before pain returns, not waiting for severe pain. 6
• Clear expectations that some pain is normal but should be manageable with prescribed medications. 8
• Contact information if pain becomes uncontrolled. 8

Common Pitfalls to Avoid

• Waiting for pain to return before starting analgesics: This reactive approach guarantees rebound pain. Start multimodal analgesia proactively. 1, 6
• Relying on regional block alone without systemic backup: Even excellent blocks eventually resolve; bridging analgesia is mandatory. 3
• Omitting dexamethasone in eligible patients: This simple intervention significantly reduces rebound pain risk. 2
• Using single-shot blocks for high-pain procedures without continuous catheter consideration: For major orthopedic surgery, continuous blocks provide superior pain control. 1
• Inadequate patient education: Patients reporting "excruciating pain" and "major distress" when blocks wear off reflects preventable failures in perioperative planning. 8