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).

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