What is the recommended pain management strategy for patients undergoing anesthesia?

Recommended Pain Management Strategy for Patients Undergoing Anesthesia

All patients undergoing anesthesia should receive multimodal analgesia consisting of acetaminophen (paracetamol), NSAIDs or COX-2 inhibitors, and intravenous dexamethasone 8-10 mg, with procedure-specific regional anesthesia when appropriate, reserving opioids strictly as rescue analgesics. 1

Core Multimodal Analgesic Regimen

Basic Pharmacological Foundation

• Acetaminophen (Paracetamol): Administer pre-operatively or intra-operatively and continue postoperatively at regular intervals 1
• NSAIDs or COX-2 Inhibitors: Start pre-operatively or intra-operatively and maintain throughout the postoperative period 1
• Intravenous Dexamethasone: Single dose of 8-10 mg intra-operatively for analgesic and anti-emetic effects (0.15 mg/kg in children) 1

This triple combination forms the foundation upon which all other interventions are added, providing synergistic pain relief while minimizing opioid requirements 2, 3.

Regional Analgesia Techniques

Procedure-specific regional blocks should be incorporated whenever feasible to maximize opioid-sparing effects 1:

• For hip arthroplasty: Fascia iliaca block or local infiltration analgesia as first-line regional technique 1
• For abdominal/pelvic surgery: Consider transversus abdominis plane (TAP) blocks or quadratus lumborum blocks 1
• For extremity procedures: Peripheral nerve blocks with long-acting local anesthetics combined with clonidine as adjunct 1

Critical caveat: Femoral nerve blocks and lumbar plexus blocks are NOT recommended for hip arthroplasty as adverse effects (motor block, falls, delayed rehabilitation) outweigh benefits 1. Epidural analgesia similarly carries risks that exceed benefits in most ambulatory settings 1.

Adjunctive Pharmacological Interventions

Intravenous Lidocaine

For major abdominal, pelvic, or spinal surgeries where regional analgesia is contraindicated or unavailable 1, 4:

• Bolus: 1-2 mg/kg followed by continuous infusion at 1-2 mg/kg/h 1
• Provides analgesic, anti-hyperalgesic, and anti-inflammatory properties 1

Low-Dose Ketamine

Reserved for specific high-risk scenarios 1, 4:

• Patients undergoing surgery with high risk of acute or chronic postoperative pain 1
• Patients with pre-existing opioid tolerance or opioid addiction 1
• Dosing: Maximum 0.5 mg/kg bolus after anesthesia induction, followed by 0.125-0.25 mg/kg/h infusion, stopped 30 minutes before surgery completion 1
• Reduces 24-hour morphine consumption by approximately 15 mg and decreases chronic pain incidence by 30% at 3 months 1

Important limitation: Postoperative continuation increases hallucination risk without substantial additional analgesic benefit 1.

Gabapentinoids

NOT recommended for routine perioperative use 1. The systematic evidence shows adverse effects (sedation, dizziness, visual disturbances) outweigh analgesic benefits in most surgical contexts 1.

Opioid Management Strategy

Rescue Analgesia Only

Opioids should be reserved exclusively as rescue analgesics for breakthrough pain after multimodal regimen implementation 1:

• Intravenous fentanyl: 0.5-1 μg/kg titrated to effect for immediate postoperative breakthrough pain 1
• Oral morphine or oxycodone: For ongoing rescue needs on the ward 1
• Reassess every 60 minutes for oral opioids, every 15 minutes for intravenous opioids 1

Dose Escalation Protocol for Breakthrough Pain

If pain score remains ≥4 despite initial rescue dose 1:

• Calculate total 24-hour opioid consumption
• Increase rescue dose by 10-20% of total 24-hour requirement 1
• If pain unchanged after 2-3 cycles, consider route change (oral to IV) or alternative strategies 1

Critical safety consideration: Fentanyl transdermal systems are absolutely contraindicated for acute postoperative pain management and should only be used in opioid-tolerant patients requiring chronic around-the-clock analgesia 5.

Special Population Considerations

Pediatric Patients

• Developmentally appropriate pain assessment tools are mandatory 1
• Multimodal approach with acetaminophen, NSAIDs (ketorolac 0.5-1 mg/kg), and regional blocks 1
• Behavioral techniques to address emotional pain components 1
• Avoid intramuscular injections due to injection aversion 1
• Dexamethasone 0.15 mg/kg for anti-inflammatory and anti-emetic effects 1

Geriatric Patients

• Same multimodal principles apply but require vigilant dose titration 1
• Altered pharmacokinetics necessitate lower initial doses with careful upward titration 1
• Use cognitive-appropriate pain assessment tools 1
• Higher vulnerability to opioid-related adverse effects (somnolence, delirium, falls) 1
• Proactive questioning required to overcome communication barriers regarding unrelieved pain 1

Critical Safety Warnings

NSAID Contraindications

Absolute contraindications 1, 4:

• Concurrent therapeutic anticoagulation (2.5-fold increased severe bleeding risk) 1, 4
• History of atherothrombotic disease (peripheral artery disease, stroke, myocardial infarction) 4
• Renal impairment with creatinine clearance <50 mL/min 4
• Duration should not exceed 7 days in patients with cardiovascular risk factors 4

Intrathecal Morphine

If spinal anesthesia is used, intrathecal morphine 0.1 mg may be considered, but the PROSPECT group emphasizes significant risks and side-effects 1. Adequate analgesia can typically be achieved with basic analgesics and regional techniques without intrathecal opioids 1.

Implementation Algorithm

Pre-operative phase:

1. Administer acetaminophen + NSAID/COX-2 inhibitor (unless contraindicated) 1
2. Patient education regarding pain expectations and management plan 1

Intra-operative phase:

1. Dexamethasone 8-10 mg IV at induction 1
2. Procedure-specific regional block with long-acting local anesthetic 1
3. Consider IV lidocaine infusion for major abdominal/pelvic/spinal cases 1
4. Low-dose ketamine only for high-risk pain scenarios 1

Postoperative phase:

1. Continue scheduled acetaminophen + NSAID 1
2. Opioids as rescue only, titrated to pain scores 1
3. Transition to oral analgesics as soon as feasible 1, 3

This evidence-based algorithmic approach prioritizes patient safety, functional recovery, and opioid minimization while ensuring adequate pain control across all surgical contexts 2, 3.