What is the recommended programmed intermittent epidural bolus (PIEB) regimen for an adult postoperative analgesia?

Programmed Intermittent Epidural Bolus (PIEB) Regimen for Adult Postoperative Analgesia

For adult postoperative analgesia, use a PIEB regimen of 6-10 mL boluses every 60 minutes with ropivacaine 0.12-0.2% plus fentanyl 2 µg/mL, combined with patient-controlled epidural analgesia (PCEA) boluses of 5 mL with a 12-20 minute lockout interval. 1, 2, 3

Optimal PIEB Settings

Bolus Volume and Interval

• Bolus size: 6-10 mL delivered every 60 minutes provides superior analgesia compared to continuous epidural infusion (CEI) 1, 2, 3
• The 10 mL bolus volume every hour demonstrates significantly less breakthrough pain (10.9%) compared to PCEA-only techniques (62.3%) 2
• Smaller 3 mL boluses every 60 minutes are effective for post-cesarean analgesia but may require higher concentrations 3

Local Anesthetic Solution

• Ropivacaine 0.12-0.2% combined with fentanyl 2 µg/mL is the preferred solution 2, 3
• Ropivacaine 0.2% provides adequate postoperative analgesia with less systemic toxicity than bupivacaine 0.125%, though it produces slightly more motor block 4
• Bupivacaine 0.0625 mg/mL (0.00625%) with fentanyl 2 µg/mL is an alternative lower-concentration option 1

PCEA Supplementation

• Add PCEA boluses of 5 mL with a 12-20 minute lockout interval to the PIEB regimen 2
• This combination reduces breakthrough pain requiring clinician intervention from 62.3% to 10.9% 2
• PCEA-only regimens without background PIEB result in significantly more breakthrough pain and motor block 2

Clinical Advantages of PIEB Over CEI

Local Anesthetic Consumption

• PIEB reduces total local anesthetic consumption by approximately 15-20% compared to CEI while maintaining equivalent or superior analgesia 1, 3
• Median bupivacaine consumption is 10.5 mg/h with PIEB versus 12.3 mg/h with CEI 1
• Total ropivacaine use at 48 hours post-cesarean is 316 mg with PIEB versus 336 mg with CEI 3

Motor Block Reduction

• PIEB produces significantly less motor block (1.6% incidence) compared to PCEA-only techniques (13.1% incidence) 2
• The intermittent bolus technique achieves better epidural spread with less motor impairment than continuous infusion 1, 5

Breakthrough Pain Management

• PIEB requires fewer manual rescue boluses (22% rate difference) compared to CEI 1
• When breakthrough pain occurs despite PIEB, administer 1-2 mL boluses of the same solution with or without adjusting the infusion rate by 1 mL/h 6
• If analgesia remains inadequate after one or two rescue boluses, consider catheter repositioning or alternative analgesic techniques 6

Implementation Considerations

Timing and Initiation

• Begin PIEB 45 minutes after intrathecal injection if using combined spinal-epidural technique 1
• For epidural-only techniques, start PIEB 15 minutes after initial epidural bolus 1
• Ensure adequate initial sensory block before transitioning to maintenance PIEB 6

Multimodal Adjuncts

• Administer dexamethasone 8 mg IV at induction to prolong analgesia and reduce postoperative nausea 7, 8
• Combine with scheduled paracetamol plus NSAID/COX-2 inhibitor started before epidural wear-off 7
• For inadequate analgesia, add IV lidocaine infusion (1-2 mg/kg bolus, then 1-2 mg/kg/h) 7, 8

Procedure-Specific Modifications

Thoracic Surgery (VATS)

• For paravertebral catheters, PIEB shows mixed results: one study found no difference versus CEI 6, while another demonstrated lower pain scores and reduced local anesthetic consumption with PIEB 6
• The programmed intermittent bolus technique achieves greater dermatomal spread in paravertebral blocks 6

Abdominal Surgery

• Thoracic epidural analgesia (TEA) is recommended for abdominal aortic surgery using PIEB delivery 6
• For rectal/pelvic surgery, maintain TEA for 48-72 hours postoperatively 6
• Lumbar epidural provides no advantage over parenteral opioids for abdominal aortic aneurysm repair 6

Critical Pitfalls to Avoid

• Never use more concentrated local anesthetic solutions for breakthrough pain management; instead, re-site the catheter or use alternative analgesia 6
• Do not delay multimodal analgesics until after epidural wear-off; this eliminates the prophylactic benefit against rebound pain 7
• Avoid epidural opioid-only infusions without local anesthetic, as combination therapy is superior for postoperative analgesia 6
• Monitor for inadequate spread in abdominoperineal resections where T10-level TEA may not cover perineal incisions; consider adding systemic opioids rather than inserting a second lumbar epidural 6