What is the recommended approach for postoperative pain management?

Postoperative Pain Management: Recommended Approach

The recommended approach for postoperative pain management is multimodal analgesia combining scheduled acetaminophen (1g every 6 hours) with NSAIDs or COX-2 inhibitors, plus a single intraoperative dose of dexamethasone 8-10 mg IV, supplemented by regional anesthesia techniques when feasible, with opioids strictly reserved as rescue analgesics only. 1, 2

Core Multimodal Analgesic Foundation

The foundation must include non-opioid analgesics started pre-operatively or intra-operatively and continued postoperatively 1, 2:

• Acetaminophen 1g every 6 hours (maximum 4g daily) should be administered first as it is safer and more effective than other drugs as a baseline analgesic 1, 3
• NSAIDs or COX-2 selective inhibitors should be started simultaneously unless contraindicated by renal impairment, heart failure, or bleeding risk 1, 2
• Single dose of IV dexamethasone 8-10 mg intra-operatively provides both analgesic and anti-emetic effects 1, 2

This combination reduces opioid consumption and related side effects through additive and synergistic mechanisms acting at different sites in the pain pathway 4, 5.

Regional Analgesia Techniques

Regional anesthesia should be incorporated whenever feasible and when it does not delay emergency procedures 4, 1:

• Epidural analgesia is recommended for major abdominal and thoracic procedures, providing potent analgesia and hastening recovery of bowel function 4, 6
• Single-shot fascia iliaca block or local infiltration analgesia is recommended for orthopedic procedures, especially in patients with contraindications to basic analgesics or high expected postoperative pain 1, 2
• Paravertebral block or erector spinae plane (ESP) block are first-line regional techniques for thoracotomy, with paravertebral block showing superior efficacy and fewer side effects compared to epidural 7
• Continuous peripheral nerve blocks (CPNB) with catheter infusion are preferred over intermittent bolus techniques 7

Opioid Management Strategy

Opioids must be reserved strictly as rescue analgesics for breakthrough pain, not as first-line therapy 1, 2, 7:

• When IV opioids are necessary, patient-controlled analgesia (PCA) is preferred over intramuscular administration, starting with bolus injection in opioid-naïve patients 4, 1
• The intramuscular route should be avoided entirely 1
• For immediate breakthrough pain in PACU, intravenous fentanyl in divided doses is the preferred opioid 1, 7
• On the ward, oral or intravenous tramadol or nalbuphine can be used as rescue medications 1

This opioid-sparing approach reduces dose-related side effects including respiratory depression, nausea, vomiting, and delayed bowel function 4, 6.

Adjuvant Medications

Additional agents can enhance the multimodal regimen in specific situations 1:

• Small doses of ketamine (maximum 0.5 mg/kg/h after anesthesia induction) are recommended in surgeries with high risk of acute pain or chronic postoperative pain, and in patients with vulnerability to pain 1
• Gabapentinoids can be considered as a component in multimodal analgesia, though systematic preoperative use is not recommended 1, 8
• Coxib administration may be considered if there are no contraindications, though coxibs and NSAIDs should never be combined as this increases myocardial infarction risk and affects kidney function 1

Pain Assessment and Monitoring

Regular pain assessment using validated tools is mandatory 4, 1:

• Numeric Rating Scale (NRS), Visual Analog Scale (VAS), or Verbal Rating Scale (VRS) should be used for communicative patients 4
• Modified FLACC scale should be used for non-communicative children, and ALGOPLUS scale for elderly patients 4
• Behavioral Pain Scale (BPS) or Critical Care Pain Observation Tool (CCPOT) should be applied in critically ill patients 4
• After any pain intervention, reassess patients for both pain control and adverse reactions at appropriate intervals 1
• When significant worsening pain is reported, reevaluate the patient for possible postoperative complications 1

Patient self-assessment is the most valuable tool, and the patient's opinion must be trusted 4.

Critical Pitfalls and Contraindications

Several important caveats must be observed 1, 2:

• NSAIDs should be avoided in patients with colon or rectal anastomoses due to potential correlation with dehiscence and wound healing inhibition 1, 2
• Acetaminophen should be used cautiously in patients with liver disease and never exceed 4g daily 1, 2
• Avoid combining coxibs and NSAIDs as their combination increases myocardial infarction incidence and affects kidney function 1
• For patients with obstructive sleep apnea syndrome (OSAS), reduce opioid use as much as possible to prevent cardiopulmonary complications 1
• Neuraxial administration of magnesium, benzodiazepines, neostigmine, tramadol, and ketamine should be avoided 1
• Avoid exceeding maximum toxic doses of local anesthetics, particularly for peri-prosthetic orthopedic infiltrations 1

Special Population Considerations

Certain patient factors increase vulnerability to severe postoperative pain and require heightened vigilance 4, 1:

• Younger age and female gender are risk factors for acute postoperative pain 1
• Preoperative pain (even far from the operating site), long-term opioid consumption, anxiety, and depression predict severe postoperative pain and chronic post-surgical pain (CPSP) 4
• Surgical procedures with duration greater than 3 hours, repeated procedures, or high-risk operations (thoracotomy, breast surgery, sternotomy) carry increased risk 4
• The APAIS scale should be used preoperatively to measure anxiety and information needs 4

Implementation and Outcomes

A combined nurse service with clinician supervision provides better outcomes in acute postoperative pain management 1. This multimodal approach not only decreases pain intensity but also increases patient comfort, improves postoperative outcomes, prevents chronic pain syndrome development, and shortens hospital stay 9, 5, 6.