Thoracic epidural analgesia

Surgical approach (context: operations commonly using thoracic epidural)

• Thoracotomy / VATS
  • Lateral decubitus, one-lung ventilation often required, intercostal retraction (thoracotomy) causes severe postoperative pain
  • Chest drains, coughing/physiotherapy essential post-op
• Oesophagectomy (open or minimally invasive)
  • Abdominal + thoracic phases, high pain burden, significant fluid shifts, respiratory complications common
• Open upper abdominal surgery (e.g. gastrectomy, pancreatic surgery, open aortic surgery)
  • Midline/rooftop incision, high opioid requirement without neuraxial analgesia

Anaesthetic management (typical when thoracic epidural used)

• Type of anaesthesia
  • Usually combined with GA for thoracic/upper abdominal surgery, epidural provides intra-op and post-op analgesia
  • Rarely sole technique (e.g. selected rib fracture analgesia in high-risk patient), but not typical
• Airway
  • ETT common, double-lumen tube or bronchial blocker for thoracic surgery, SGA uncommon for major surgery
• Duration
  • Depends on surgery: thoracotomy 2–4 h, oesophagectomy 4–8 h, major upper abdominal 3–6 h (typical ranges)
• How painful?
  • Thoracotomy and oesophagectomy: very painful, pain impairs ventilation/cough → atelectasis/pneumonia risk
  • Upper abdominal laparotomy: severe pain, epidural reduces opioid-related respiratory depression and ileus
• Intra-op considerations when epidural running
  • Expect sympathectomy-related hypotension, treat with vasopressors and judicious fluids, consider arterial line for major cases
  • Opioid-sparing: reduce systemic opioid dosing, monitor ventilation and depth carefully

Definition and aims

• Placement of an epidural catheter in the thoracic epidural space to deliver local anaesthetic ± opioid for segmental analgesia.
• Aims: excellent dynamic analgesia (coughing/mobilisation), reduced pulmonary complications, reduced systemic opioid requirement, improved patient satisfaction.

Indications (common FRCA list)

• Thoracic surgery: thoracotomy, VATS (selected), rib fracture analgesia (especially multiple fractures/flail chest).
• Upper abdominal surgery: open gastrectomy, hepato-pancreato-biliary surgery, open aortic surgery, oesophagectomy.
• Major abdominal surgery where enhanced recovery prioritises opioid-sparing and early mobilisation (institution-dependent).

Contraindications

• Absolute
  • Patient refusal, lack of consent/capacity without appropriate best-interest process
  • Infection at insertion site, untreated systemic sepsis (relative-to-absolute depending on severity and source control)
  • Uncorrected coagulopathy / anticoagulation not meeting neuraxial safety intervals
  • Raised intracranial pressure due to mass lesion (risk of herniation with dural puncture/CSF leak)
• Relative
  • Hypovolaemia/haemodynamic instability, severe aortic stenosis or fixed cardiac output states (risk profound hypotension)
  • Severe spinal deformity, previous thoracic spine surgery, difficult anatomy
  • Neurological disease (e.g. MS, peripheral neuropathy): discuss risk/benefit and document baseline deficits
  • Bacteraemia, immunosuppression: higher infection risk, ensure strict asepsis and close monitoring

Relevant anatomy (thoracic epidural specifics)

• Epidural space: potential space between ligamentum flavum and dura, contains fat, lymphatics, epidural veins (valveless).
• Thoracic features: narrower epidural space than lumbar, spinous processes more angulated, ligamentum flavum may have midline gaps (false loss of resistance).
• Dermatomes (useful targets): T4 nipple, T6 xiphisternum, T10 umbilicus, upper abdominal incisions often require ~T6–T10 coverage.
• Sympathetic outflow T1–L2: thoracic epidural can cause sympathectomy → vasodilation, hypotension, high block may affect cardiac accelerator fibres (T1–T4).

Preparation, consent, and monitoring

• Consent: benefits (superior dynamic analgesia, opioid-sparing) and risks (failure, hypotension, dural puncture, nerve injury, infection, haematoma, local anaesthetic toxicity).
• Check anticoagulation/antiplatelets and timing for insertion and removal, document plan for postoperative thromboprophylaxis.
• Baseline neuro exam: lower limb power/sensation, document pre-existing deficits.
• Monitoring: standard monitors, IV access, consider arterial line for major surgery or if epidural-induced hypotension anticipated.
• Asepsis: hat/mask, sterile gown/gloves, chlorhexidine in alcohol (allow to dry), sterile drapes, sterile catheter fixation and bacterial filter.

Technique (stepwise)

• Position: sitting or lateral, flexion to open interspinous spaces, ensure patient comfort and stillness.
• Level selection: choose based on incision dermatomes, commonly T5–6 for thoracotomy, T6–8 for upper abdominal surgery (institutional variation).
• Approach: midline or paramedian (often easier in thoracic region due to angulated spinous processes).
• Identify epidural space: loss of resistance to saline (commonly preferred) or air (avoid if possible due to patchy block/pneumocephalus risk).
• Thread catheter 3–6 cm into epidural space (balance: dislodgement vs unilateral/intravascular placement).
• Aspirate gently, give test dose as per local policy (e.g. lidocaine with adrenaline) and interpret carefully in anaesthetised patients.
• Secure catheter well, label clearly, document insertion depth, catheter at skin, level, complications, and initial dosing.

Drug choices and dosing (typical regimens)

• Local anaesthetic options
  • Bupivacaine 0.1–0.125% or ropivacaine 0.1–0.2% for infusion (aim: analgesia with minimal motor block).
  • Stronger solutions (e.g. bupivacaine 0.25%) may be used as incremental boluses for rescue, with close haemodynamic monitoring.
• Opioid adjunct
  • Fentanyl (e.g. 2 mcg/mL) commonly added to infusion, improves analgesia and reduces LA dose requirement.
  • Epidural opioids: risks include pruritus, nausea, urinary retention, and respiratory depression (especially with hydrophilic opioids).
• Infusion rates (typical adult ranges, tailor to patient and haemodynamics)
  • Often 6–12 mL/h of low-concentration LA ± fentanyl, use patient-controlled epidural analgesia (PCEA) where available.
• Intra-operative use
  • Can be activated pre-induction (awake) or after induction, pre-induction allows assessment of block but may cause hypotension before GA.
  • If dosing under GA: incremental boluses with vigilant monitoring, avoid large bolus if uncertain catheter position.

Physiological effects (what to say in viva)

• Analgesia: segmental sensory block reduces stress response and improves ability to breathe deeply and cough.
• Cardiovascular: sympathectomy → ↓SVR and venous pooling → hypotension, high thoracic block may cause bradycardia (T1–T4).
• Respiratory: improved pain control improves ventilation, intercostal motor block can occur but clinically usually outweighed by analgesic benefit, caution in severe respiratory failure.
• GI: reduced ileus and improved gut perfusion/motility (multifactorial, also opioid-sparing).
• Renal: hypotension can reduce renal perfusion, maintain MAP, neuraxial does not directly impair renal function if perfusion maintained.

Postoperative management

• Regular assessment: pain scores at rest and on movement, sensory level, motor block, sedation/respiratory rate, BP/HR, nausea/pruritus, catheter site.
• Multimodal analgesia: paracetamol ± NSAID (if appropriate), consider adjuncts (e.g. gabapentinoids selectively), avoid duplicating opioids if epidural opioid running.
• Hypotension management: treat cause (block height, hypovolaemia, bleeding), reduce epidural rate if needed, vasopressors often required (e.g. metaraminol/noradrenaline per local practice).
• Mobilisation and VTE prophylaxis: coordinate timing of LMWH/DOAC with epidural presence and removal, document clearly.
• Weaning/removal: step down infusion when oral analgesia established, remove with appropriate anticoagulation intervals, inspect catheter tip if concerns, document intact removal.

Complications and management (high-yield)

• Failure / patchy / unilateral block
  • Causes: incorrect level, catheter not in epidural space, lateral placement, migration, inadequate dosing.
  • Management: check catheter depth/dressing, assess sensory level, give incremental bolus, consider withdrawing catheter 1–2 cm, consider replacement if inadequate for major surgery.
• Hypotension / bradycardia
  • Treat: left uterine displacement in pregnancy (if relevant), fluids if hypovolaemic, vasopressors, reduce/stop infusion temporarily, consider high block.
• Dural puncture and post-dural puncture headache (PDPH)
  • Recognise: CSF aspiration or sudden loss, PDPH post-op (postural headache).
  • Immediate options: resite at different level, consider intrathecal catheter (local policy) to reduce PDPH and provide analgesia.
  • PDPH management: hydration, simple analgesia, caffeine, epidural blood patch for persistent/severe symptoms after assessment and consent.
• High/total spinal (unrecognised intrathecal dosing)
  • Features: rapid hypotension, bradycardia, difficulty breathing, upper limb weakness, LOC.
  • Management: call for help, airway/ventilation, vasopressors (adrenaline boluses/infusion as needed), IV fluids, left lateral tilt if pregnant, treat as high neuraxial block.
• Intravascular injection / local anaesthetic systemic toxicity (LAST)
  • Features: tinnitus, metallic taste, agitation, seizures, arrhythmias/cardiac collapse (may be masked under GA).
  • Management: stop LA, airway/oxygen, treat seizures (benzodiazepine), follow lipid rescue protocol, manage arrhythmias (avoid large doses of vasopressin, cautious adrenaline).
• Epidural haematoma
  • Presentation: severe back pain, progressive motor weakness/sensory change, sphincter dysfunction, may occur after insertion or removal.
  • Action: emergency—stop infusion, urgent neuro exam, immediate MRI, urgent neurosurgical/spinal referral, decompression ideally within hours.
• Epidural abscess / meningitis
  • Presentation: back pain, fever, neurological deficit, raised inflammatory markers, catheter site infection may be present.
  • Action: urgent imaging (MRI), cultures, antibiotics, surgical input, remove catheter if infection suspected.
• Neurological injury
  • Causes: direct trauma, ischaemia (hypotension), haematoma/abscess, neurotoxicity.
  • Management: stop infusion, urgent assessment and escalation, exclude compressive causes urgently.
• Opioid-related adverse effects (if opioid in epidural)
  • Pruritus, nausea/vomiting, urinary retention, sedation/respiratory depression (monitor RR and sedation score).
  • Management: antiemetics, low-dose naloxone infusion for troublesome pruritus/resp depression (balance analgesia), consider reducing opioid concentration.

Troubleshooting a poorly functioning thoracic epidural (structured approach)

• Assess patient and rule out emergencies first: new motor block, severe back pain, fever, hypotension out of proportion → stop infusion and escalate.
• Check basics: pump settings, line connections, filter, clamp, kinks, leakage, catheter migration, dressing integrity.
• Assess block: map dermatomes (cold/alcohol swab), unilateral vs bilateral, height relative to incision, check motor power.
• Interventions: incremental bolus, adjust rate, consider withdrawing catheter 1–2 cm if unilateral, consider resiting early if inadequate for thoracotomy/major surgery.
• Alternative plans if failed: IV PCA opioid, regional alternatives (paravertebral/erector spinae plane), wound catheters, multimodal analgesia.

Thoracic epidural vs alternatives (typical viva comparison points)

• Paravertebral block: unilateral analgesia, less hypotension/urinary retention, risk pneumothorax, may be preferred for some thoracic procedures.
• Erector spinae plane (ESP) block: easier/safer plane, variable efficacy, useful when neuraxial contraindicated.
• Systemic opioids: simpler but more sedation, respiratory depression, ileus, poorer dynamic analgesia.
• Key trade-off: epidural often best dynamic analgesia but higher risk of hypotension and neuraxial complications, requires skilled follow-up.

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