What are the indications, contraindications, and typical dosing regimen for epidural analgesia in labor and postoperative pain?

Epidural Analgesia: Indications, Contraindications, and Dosing

Epidural analgesia should be offered to all laboring women on an individualized basis regardless of cervical dilation, and neuraxial techniques do not increase cesarean delivery rates. 1

Indications

Labor Analgesia

• Primary indication: Pain relief during labor, considered by >75% of primiparas as extremely painful 1, 2
• Early placement recommended for:
  • Twin gestation 1
  • Preeclampsia 1
  • Anticipated difficult airway or obesity 1
  • Trial of labor after cesarean delivery (TOLAC) 1
  • Anticipated complications requiring potential operative delivery 1

Operative Delivery

• Cesarean section (planned or emergent) 1, 3
• Forceps or vacuum-assisted delivery 1
• Removal of retained placenta (if catheter in place and patient hemodynamically stable) 1

Postoperative Pain Management

• Major abdominal surgery (thoracic, upper/lower abdominal) 4
• Orthopedic procedures 4
• Vascular surgery 4
• Postpartum tubal ligation 1

Contraindications

Absolute Contraindications

• Patient refusal 5
• Maternal hemorrhage with hemodynamic instability 1, 5
• Coagulopathy 5

Relative Contraindications (Assess hemodynamic status before proceeding)

• Hemodynamic instability 1

Dosing Regimens

Labor Analgesia - Initiation

Continuous Epidural Infusion (CEI):

• Bupivacaine 0.0625-0.125% with fentanyl 2-2.5 μg/mL 1, 6
• Alternative: Ropivacaine 0.175-0.2% with fentanyl 2-2.5 μg/mL 6
• Infusion rate: 1-3 mL/hour 6, 7
• Goal: Use lowest concentration providing adequate analgesia with minimal motor block 1

Combined Spinal-Epidural (CSE) - Initial Spinal Dose:

• Bupivacaine 1.5-2.5 mg with fentanyl 5-20 μg 7
• Alternative: Ropivacaine 2-5 mg with fentanyl 5-20 μg 7
• Or sufentanil 2.5-7.5 μg instead of fentanyl 7
• Provides rapid onset with effective analgesia 1, 8

Single-Shot Spinal (Time-Limited):

• Use only when spontaneous vaginal delivery anticipated 1, 8
• If labor expected to last longer than drug duration or operative delivery possible, use catheter technique instead 1, 8

Labor Analgesia - Maintenance

Patient-Controlled Epidural Analgesia (PCEA):

• Preferred over fixed-rate CEI for fewer interventions, reduced local anesthetic doses, and less motor blockade 1, 8
• Background infusion: 1-3 mL/hour of maintenance solution 6
• Patient bolus: 0.5-1 mL every 20-30 minutes 6, 7
• May be used with or without background infusion 1, 8

Breakthrough Pain Management:

• Administer 1-2 mL of same maintenance solution 6, 7
• If inadequate after additional 2 mL bolus, remove catheter and consider re-siting or alternative analgesia 6

Cesarean Section Anesthesia

Spinal Anesthesia (Preferred):

• Intrathecal morphine 50-100 μg (or diamorphine up to 300 μg) for postoperative analgesia 3
• Alternative: Epidural morphine 2-3 mg (or diamorphine 2-3 mg) if using epidural catheter 3

Converting Labor Epidural to Cesarean Anesthesia:

• Incremental doses of local anesthetic to achieve T4 sensory level 7
• Bupivacaine 0.5% in 1.25 mg increments every 3 minutes 6
• Or bupivacaine 0.75% incrementally (total 15-25 mg typical) 6
• Add fentanyl or sufentanil plus morphine or diamorphine 7
• Initiate dosing only in operating room 7

Postoperative Pain Management (Non-Obstetric)

Continuous Epidural Infusion:

• Bupivacaine 0.25% or ropivacaine 0.2% at 7.5 mL/hour 4
• Add sufentanil 5-10 μg/hour if needed for breakthrough pain 4
• Or morphine 3 mg boluses every 8-12 hours 4
• Single-dose epidural morphine: 2-4 mg provides 10.7 hours mean duration 9

Monitoring Requirements

During Labor with Epidural

• Blood pressure: Every 5 minutes for 15 minutes after initial dose and each top-up 6
• Sensory level: Check hourly 10
• Motor block: Check hourly using straight-leg raise test (ability to lift heel off bed) 10
• Alert anesthesiologist if unable to perform straight-leg raise 10
• Midwife must remain in room during initial 15-minute monitoring period 6

After Intrathecal Morphine

• Respiratory rate and sedation level: Every hour for 12 hours, then every 2 hours for next 12 hours 7

Key Clinical Pearls

Needle Selection:

• Use pencil-point spinal needles instead of cutting-bevel needles to minimize post-dural puncture headache risk 1, 8

Multimodal Analgesia for Cesarean Section:

• Oral paracetamol pre-operatively 3
• IV paracetamol intra-operatively if not given pre-op 3
• IV NSAIDs intra-operatively 3
• IV dexamethasone intra-operatively (provides analgesia and anti-emetic effect) 3

Common Pitfalls:

• Motor block occurs in up to 6.5% with low-dose techniques 4
• Hypotension occurs in ~21% of cases 4
• Temporary bladder voiding disorders in 8% 4
• Post-puncture headache in 1.2% 4