Combined spinal–epidural (cse)

Surgical approach (if applicable)

• Not an operation: CSE is an anaesthetic technique used to facilitate surgery/obstetrics (e.g. labour analgesia, caesarean section, lower limb/hip surgery).

Anaesthetic management (typical use-cases)

• Type of anaesthesia: Regional (neuraxial) ± sedation; may convert to GA if failure/complications.
• Airway: Usually none; oxygen via nasal cannulae/face mask. If conversion to GA: ETT typically (rapid sequence in obstetrics).
• Duration: Spinal provides rapid onset (minutes) but finite duration; epidural allows top-ups/infusion for hours and postoperative analgesia.
• How painful: Depends on surgery. CSE can provide dense surgical anaesthesia (e.g. CS, lower limb) and/or excellent labour analgesia; epidural component enables prolonged analgesia and titration.

Definition and aims

• Combined spinal–epidural: deliberate placement of an epidural catheter with a spinal injection in the same sitting (either through the epidural needle or at a separate interspace).
• Aims: rapid onset (spinal) + flexibility/prolongation (epidural) + ability to extend block level/duration and provide postoperative analgesia.

Indications

• Obstetrics
  • Labour analgesia: rapid pain relief with ability to maintain/extend analgesia.
  • Caesarean section (elective/urgent): rapid onset spinal with epidural as backup/for extension (e.g. prolonged surgery, high BMI, difficult neuraxial).
• Orthopaedics/vascular/lower abdominal surgery
  • Hip/knee arthroplasty (esp. when prolonged surgery anticipated) and for postoperative analgesia.
  • Lower limb vascular procedures where titration and postoperative analgesia are beneficial.
• Situations where a single-shot spinal may be insufficient: uncertain duration, need for incremental extension, or desire to minimise intrathecal dose while retaining ability to top up.

Contraindications (as for neuraxial techniques)

• Absolute
  • Patient refusal/capacity concerns.
  • Infection at site; untreated systemic sepsis (relative/individualised, but generally avoid).
  • Uncorrected coagulopathy/unsafe anticoagulation status (follow local policy/ASRA/ESAIC guidance).
  • True allergy to intended drugs (rare).
  • Raised ICP due to mass lesion (risk of herniation).
• Relative
  • Hypovolaemia/shock, severe aortic stenosis or other fixed-output states (risk profound hypotension).
  • Severe spinal deformity/previous surgery (technical difficulty; consider ultrasound/alternative).
  • Fever/bacteraemia, immunosuppression (risk–benefit).
  • Neurological disease (document baseline; discuss risks).

Techniques

• Needle-through-needle (single interspace)
  • Locate epidural space with Tuohy (loss of resistance). Pass long spinal needle through Tuohy to puncture dura and inject intrathecal drug; then thread epidural catheter.
  • Advantages: one skin puncture, faster, commonly used in obstetrics.
  • Disadvantages: potential for catheter migration through dural hole (rare), reliance on correct alignment, risk of spinal needle damage/deflection.
• Separate-needle technique (two interspaces or same interspace with separate punctures)
  • Spinal performed separately (often lower space), epidural catheter placed at another space.
  • Advantages: less theoretical risk of epidural catheter passing intrathecally; can choose optimal levels.
  • Disadvantages: two punctures; may be slower.
• Sequential CSE
  • Small intrathecal dose to reduce haemodynamic instability, then incremental epidural dosing to achieve required block.
  • Useful in frail/elderly, cardiac disease, high sympathectomy risk, or where a high block is needed but you want titration.

Drugs and dosing (typical examples; local protocols vary)

• Labour analgesia (CSE): intrathecal opioid ± very low-dose LA, then epidural infusion/PIEB.
  • Intrathecal: fentanyl 10–25 micrograms ± bupivacaine 1–2.5 mg (or equivalent).
  • Epidural maintenance: low-dose LA + opioid (e.g. bupivacaine/ropivacaine 0.0625–0.1% + fentanyl 2 microg/mL) via PCEA/PIEB.
• Caesarean section: intrathecal hyperbaric bupivacaine + opioid; epidural as backup/for extension.
  • Intrathecal: hyperbaric bupivacaine 0.5% typically 10–12 mg + fentanyl 10–20 microg ± diamorphine 300–400 microg (or morphine 100–150 microg).
  • Epidural top-up if needed: fractionated doses of lidocaine 2% with adrenaline ± bicarbonate, or chloroprocaine where available; monitor closely for high/total spinal if epidural dosing soon after spinal.
• Lower limb/hip surgery: intrathecal bupivacaine (dose tailored) ± opioid; epidural for supplementation/analgesia.
  • Intrathecal: bupivacaine 0.5% heavy 10–15 mg (adjust for age/height/pregnancy).
  • Epidural: LA boluses/infusion for postoperative analgesia (balance against hypotension/motor block and mobilisation goals).

Preparation and conduct

• Pre-assessment: indication, contraindications, anticoagulation timing, baseline neurology, airway plan if conversion to GA, consent including failure/complications.
• Monitoring: standard (ECG, NIBP, SpO2); consider arterial line in high-risk patients; frequent BP cycling after spinal (e.g. 1–2 min initially in obstetrics).
• IV access and fluids: reliable cannula; avoid routine large preloads—use co-load and vasopressors as needed (esp. obstetrics).
• Asepsis: full sterile technique; chlorhexidine in alcohol (allow to dry); sterile gown/gloves/drape; mask and hat.
• Position: sitting or lateral; optimise flexion; consider ultrasound for difficult anatomy.
• Epidural space: loss of resistance (saline often preferred by some to reduce patchy block/pneumocephalus risk).
• Spinal injection: confirm free CSF; inject intrathecal drug; remove spinal needle; thread epidural catheter (commonly 4–6 cm in epidural space).
• Catheter management: aspirate; label clearly; secure well; document depth and interspace.
• Testing the epidural: controversial immediately after spinal because spinal block may mask intrathecal placement; use cautious approach (see below).

Epidural test dose after CSE (practical approach)

• Problem: spinal anaesthesia/analgesia can mask signs of intrathecal or intravascular injection (motor/sensory changes and pain response).
• Principles
  • If you must dose the epidural soon after spinal, give small incremental doses with close monitoring of BP/HR, block height, and symptoms.
  • Avoid large boluses until catheter position/function is reasonably assured.
  • In obstetrics, if using adrenaline-containing test dose, interpret tachycardia cautiously (pain/anxiety/uterine contractions).
• Options used in practice
  • Delay formal test dose until spinal has regressed (labour CSE often does this).
  • Use a very small test dose (e.g. 3 mL lidocaine 1.5% with adrenaline 1:200,000) with vigilant monitoring; recognise reduced sensitivity.
  • Use fractionated epidural dosing as the functional test (e.g. 5 mL aliquots) while watching for high block or systemic toxicity.

Physiology and block characteristics

• Spinal: rapid onset, dense sensory and motor block; sympathetic block → vasodilation, hypotension, reduced venous return.
• Epidural: slower onset, segmental, titratable; can extend duration/height and provide postoperative analgesia.
• CSE may produce faster onset than epidural alone and better sacral spread for labour analgesia; epidural component can be more reliable after dural puncture (possible translocation of LA through dural hole).

Complications

• Common/important
  • Hypotension/bradycardia (high sympathectomy).
  • High/total spinal (especially if epidural dosing given after unrecognised intrathecal catheter placement or rapid epidural top-up soon after spinal).
  • Failed/patchy epidural catheter (despite good spinal).
  • Post-dural puncture headache (intentional dural puncture with small-gauge spinal needle: lower risk than accidental Tuohy puncture, but not zero).
  • Pruritus, nausea, urinary retention (opioids/neuraxial).
• Serious but rare
  • Epidural haematoma (time-critical).
  • Epidural abscess/meningitis.
  • Local anaesthetic systemic toxicity (LAST) from epidural/intravascular injection.
  • Nerve injury (direct trauma, ischaemia, compressive lesions).
  • Respiratory depression (neuraxial opioids—early with lipophilic opioids; delayed with morphine/diamorphine).

Management of key complications (high-yield)

• Hypotension after spinal/CSE
  • Left uterine displacement in pregnancy; optimise position; oxygen; rapid BP cycling.
  • Vasopressors: phenylephrine (commonly first-line in obstetrics) or ephedrine depending on HR and context; treat bradycardia with atropine/glycopyrrolate; consider adrenaline in severe collapse.
  • IV fluids (co-load), assess for aortocaval compression, haemorrhage, or high block.
• High/total spinal
  • Recognise: rapid ascending numbness, dyspnoea, hypotension, bradycardia, arm weakness, nausea, loss of consciousness/apnoea.
  • Immediate actions: call for help; airway support, 100% O2; ventilate; intubate early if deteriorating; left uterine displacement if pregnant.
  • Circulation: vasopressors (phenylephrine/metaraminol/ephedrine; adrenaline boluses/infusion if severe), IV fluids; treat bradycardia.
  • Reassure; continue anaesthesia/sedation as needed; anticipate prolonged ventilation until block recedes.
• PDPH
  • Conservative: hydration, simple analgesia/NSAIDs (if appropriate), caffeine; consider antiemetics.
  • Epidural blood patch for significant postural headache affecting function or with neurological symptoms; exclude red flags first.
• Epidural haematoma/abscess
  • Red flags: severe back pain, motor weakness, sensory change, sphincter disturbance, fever (abscess).
  • Urgent MRI and neurosurgical/spinal referral; time-critical decompression for haematoma.
• LAST
  • Stop LA, call for help, airway/oxygen/ventilation, treat seizures (benzodiazepine), follow lipid rescue protocol, manage arrhythmias (avoid large doses of propofol in unstable patients).

CSE in obstetrics: specific considerations

• Advantages in labour: very rapid analgesia, good sacral coverage, high maternal satisfaction; epidural allows ongoing analgesia and conversion for operative delivery.
• Potential disadvantages: pruritus, transient fetal heart rate changes, uterine hypertonus (reported), hypotension; need for close monitoring immediately after intrathecal opioid/LA.
• If urgent CS needed later: epidural catheter already in situ can be topped up (but ensure it is functioning well throughout labour).

Documentation and post-procedure care

• Record: consent, asepsis, interspace, needle types/gauges, depth to epidural space, catheter length at skin, drugs/doses, complications, block level, haemodynamics, and ongoing plan.
• Post-procedure: regular observations (BP, HR, RR, sedation score), sensory/motor block, pain scores, catheter site checks; neuraxial opioid monitoring per policy.
• Removal: coordinate with anticoagulation timing; document catheter tip intact; provide safety-net advice (PDPH, infection, neuro symptoms).