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Introduction

GasNovice Labour Analgesia Recipes

GasNovice Labour Analgesia Recipes 2

Pre-Labour Assessment

Task	Details
History & examination	Obstetric, medical, anaesthetic history; airway, spine, CVS, respiratory review
Laboratory tests	Platelet count only if indicated (PET, HELLP, anticoagulants)–neuraxial acceptable if ≥ 70 × 10⁹ L⁻¹ and stable
Fetal status	Confirm reassuring CTG with obstetrician
Resources	Check trained staff, resuscitation and difficult-airway equipment
Consent	Technique, benefits, risks (PDPH, motor block, conversion to CS), financial implications

Pain Pathways in Labour

Stage	Pain type	Dermatomes	Afferent pathway
1st (latent/active)	Visceral (uterine contraction, cervical dilation)	T11–L1 → T10–L1	Sympathetic fibres via uterovaginal → inferior hypogastric plexus → dorsal roots
2nd	Somatic (perineum, vagina, pelvic floor)	T10–S4 (pudendal S2-S4)	Pudendal & perineal branches via sacral plexus

Analgesic Options

Non-pharmacological (evidence-based)

• Continuous one-to-one support, breathing & relaxation techniques
• Water immersion (significant pain-score reduction)
• Acupuncture, acupressure, sterile-water injections
• TENS–modest benefit in back-dominant pain

Systemic Pharmacological Agents

Drug	Typical regimen	Key points
Pethidine (meperidine)	25–50 mg IM or 10–25 mg IV (max 100 mg/4 h)	Limited by nausea & neonatal sedation; avoid <4 h before delivery
Remifentanil PCA	20–40 µg demand bolus, 2 min lock-out; no basal	Rapid onset/offset; superior satisfaction vs pethidine; requires 1:1 monitoring & pulse oximetry
Fentanyl bolus	25–100 µg IV q1 h PRN	Minimal neonatal depression; useful while awaiting neuraxial
Ketamine	10–15 mg IV for rescue just before delivery	>1 mg kg⁻¹ may cause uterine hypertonus
Antiemetics/Anxiolytics	Promethazine 12.5 mg IV; hydroxyzine 25 mg IM	Use sparingly; routine midazolam discouraged (amnestic, neonatal hypotonia)
NSAIDs	Avoid during labour–risk of ductus arteriosus constriction & uterine atony

Neuraxial Analgesia

General Principles

• Low-dose LA (≤0.1 % bupivacaine/ropivacaine) + lipophilic opioid (fentanyl 2 µg mL⁻¹ or sufentanil 0.3 µg mL⁻¹) balances analgesia and motor preservation.
• Programmed Intermittent Epidural BolusPIEB (6–10 mL q30–45 min) with PCEA demand 5–8 mL achieves lowest rescue rate and drug consumption.
• Vasopressor (phenylephrine 25–50 µg min⁻¹) superior to fluid loading for hypotension prophylaxis.

Fluid & Vasopressor Strategy

Strategy	Evidence
Crystalloid co-load 10–15 mL kg⁻¹ at block placement	Non-inferior to colloid when combined with prophylactic vasopressor
Colloid preload	Marginal additional benefit but ↑ cost and allergy risk

Epidural Technique

1. Placement–L3-4 or L4-5, loss-of-resistance to saline; limit air ≤2 mL.
2. Catheter–Multi-orifice 4–5 cm in space.
3. Test–Incremental 3 mL 0.1 % bupivacaine + adrenaline 5 µg mL⁻¹ (observe HR & sensory change).
4. Initial bolus–10 mL 0.1 % bupivacaine + fentanyl 2 µg mL⁻¹ in 5 mL aliquots.
5. Maintenance–PIEB 8 mL q40 min with PCEA 6 mL, lock-out 10 min; no basal infusion.
6. Troubleshooting–Additional 5 mL bolus; adjust catheter; re-site early if asymmetric or ineffective after two clinician boluses.

Conversion to Caesarean Anaesthesia

• Treat epidural placed > 60 min ago as untested.
• Top-up with alkalinised lidocaine 2 % with adrenaline + fentanyl (total 15–20 mL).
• If surgical block not to T4 within 10 min → spinal (preferred) or GA.

Dosage Summary at GSH

• Test Dose:
  • 2.5 mL of 2% lignocaine, wait 5 min
• Bolus Dose:
  • Mix: 5 mL 0.5% bupivacaine + 4 mL saline + 50 mcg fentanyl
    • 10ml= 0.25% Bupivacaine and 5ug/ml fentanyl
  • Administer two 4 mL boluses 3 min apart
  • Measure BP every 5 min, test level in 20 min (Aim T8-T10)
• Infusion:
  • Mix: 76 mL saline + 20 mL 0.5% bupivacaine + 200 mcg fentanyl (0.1% bupivacaine with 2ug:ml fentanyl in total 100ml)
  • Rate: 8-14 mL/hour (start when block no higher than T8)
• Breakthrough Pain:
  • 1.5 mL per segment of 0.25% bupivacaine or 5-10 mL 0.1% solution with 25 mcg fentanyl
• Top-Up for C/S:
  • Mix: 17 mL 2% lignocaine + 50 mcg fentanyl + 1 mL 8.4% sodium bicarbonate + 1 mL 1/10000 adrenaline
  • Administer 5 mL boluses after test dose
  • Requires 16-22 mL for effective T4 block

Advantages of Regional over Systemic Analgesia

• Neonatal–Higher umbilical pH, less need for resuscitation than systemic opioids.
• Maternal–Reduced pulmonary aspiration risk, lower catecholamines → improved uteroplacental perfusion, readiness for emergency CS, superior postpartum pain control with intrathecal morphine.

Motor Block Classification

Spinal/Epidural Techniques

Local Anaesthetics (low-concentration regimens) for Epidural

Drug	Common concentration range*	Typical hourly consumption†
Bupivacaine	0.05 – 0.10 %	6–12 mg h⁻¹
Levobupivacaine	0.05 – 0.10 %	6–12 mg h⁻¹
Ropivacaine	0.08 – 0.20 %	8–16 mg h⁻¹

• *Concentrations ≤0.1 % minimise motor block and instrumental delivery rates without compromising analgesia.
• †Assumes average basal or programmed dosing; adjust for maternal weight and technique.

Opioid and Non-opioid Adjuncts

Agent (typical epidural concentration)	Benefits	Caveats
Opioid Adjuncts	–	–
Fentanyl 1.5–3 µg mL⁻¹	Rapid onset, improves sacral analgesia, reduces LA requirement	Pruritus, nausea, respiratory depression (rare)
Sufentanil 0.3–0.5 µg mL⁻¹	High potency, long duration, synergistic with LA	Similar side effects as fentanyl; avoid overdose
Morphine (preservative-free) 0.1–0.2 mg for spinal (bolus)	Long-duration analgesia post-C/S	Delayed respiratory depression; avoid in labour epidural
Non-opioid Adjuncts	–	–
Epinephrine 2 µg mL⁻¹	↓ Minimum Local Analgesic Concentration (MLAC); prolongs block	↑ Motor block; tachycardia
Clonidine 1–2 µg mL⁻¹	Potentiates LA without ↑ motor block	Maternal sedation, hypotension; FDA boxed warning (US)
Dexmedetomidine 0.3–0.5 µg mL⁻¹	Superior early analgesia, LA-sparing; may enable opioid-free regimens	Dose-dependent bradycardia; limited obstetric data
Neostigmine 2–4 µg mL⁻¹	Only useful when combined with clonidine	Nausea at higher doses
Routine magnesium or ketamine adjuvants remain investigational.

• Opioid sparing with dexmedetomidine or esketamine reduces pruritus and preserves uterine activity, but experience remains limited to small trials.

Opioid-Only Neuraxial Analgesia (Labour)

• Description: Administration of lipophilic opioids (e.g., fentanyl, sufentanil) or hydrophilic opioids (e.g., morphine) into the intrathecal or epidural space without local anaesthetic.
• Use Case: Often used for rapid-onset analgesia when delivery is imminent or in cases where LA-induced motor block is undesirable.
• Common Regimens:
  • Intrathecal:
    • Fentanyl 10–25 µg or
    • Sufentanil 2.5–5 µg
  • Epidural:
    • Fentanyl 50–100 µg bolus or
    • Sufentanil 10–20 µg bolus
• Advantages: No motor block, fast onset, improved maternal mobility.
• Limitations: Short duration (especially with intrathecal lipophilic opioids), pruritus, nausea, and rare respiratory depression.
• Not recommended as sole maintenance for prolonged labour—best for short duration or bridge therapy.

Epidural Test Dose–2023 Consensus Update

Position	Rationale & current practice
For an adrenaline-containing test dose (3 mL lignocaine 1.5 % + adrenaline 5 µg mL⁻¹) when imminent conversion to CS is likely.	Facilitates early recognition of intravascular or intrathecal catheters.
Against universal test dosing in low-dose labour regimens; instead favour aspiration + incremental 5 mL dosing.	Low LA concentrations carry minimal toxicity; tachycardic response blunted in pregnancy; false negatives common.

Epidural Maintenance

Technique	Key points	Evidence-based advantages	Important limitations
Manual intermittent bolus	10–15 mL clinician-delivered bolus when pain recurs	Simple equipment	Breakthrough pain, variable spread, high workload
Continuous epidural infusion (CEI)	6–12 mL h⁻¹ of dilute LA ± opioid	Steady analgesia in busy units	Higher total LA dose than bolus-based regimens
Patient-controlled epidural analgesia (PCEA)	Demand bolus 5–8 mL, lock-out 10–15 min	↓ LA use; ↑ maternal satisfaction	Requires patient engagement; risk of under-dosing in late labour
PCEA + basal infusion	Basal 4–6 mL h⁻¹ plus PCEA	Fewer clinician interventions; superior comfort in long second stage	LA consumption slightly ↑ vs demand-only PCEA
Programmed intermittent epidural bolus (PIEB)	Automated 6-10 mL bolus q30-60 min (often with PCEA)	Superior dermatomal spread, less motor block, ↓ rescue dosing, ↑ satisfaction	Requires modern pumps; optimal volume–interval pairing still under study
Computer-integrated PCEA (CIPCEA)	Pump adjusts basal rate to recent PCEA requests	Maintains low LA use while preventing breakthrough pain	Cost; limited availability
Closed-loop/automated systems	Algorithm titrates bolus size to real-time pain scores or PCEA frequency	Promising pilot data; potential to reduce clinician workload	Experimental

• Current best practice
  • PIEB combined with PCEA is the preferred technique in high-resource settings, delivering the lowest rescue bolus rate and drug consumption while maintaining maternal satisfaction. In low-resource units, CEI with dilute solutions remains acceptable when pump technology is limited.

Impact of Neuraxial Analgesia on Labour & Delivery Outcomes

Duration of Labour

Stage	Contemporary evidence	Practical implications
First stage	Meta-analyses of >25 000 parturients show no clinically relevant prolongation (mean difference <10 min) when low-concentration epidurals (≤0.1 % bupivacaine-equivalent) are used.	Timing of epidural (early vs ≥5 cm dilatation) does not influence progress or mode of delivery.
Second stage	Pooled data indicate a modest increase (≈15–20 min) that is greatest in nulliparas and with higher LA concentrations; ultra-low solutions (≤0.06 %) abolish this effect.	Do not discontinue the epidural—reduce basal rate once the head is on the perineum to preserve pushing sensation.
Third stage	No prolongation attributable to epidural analgesia.

Caesarean Section (CS) Rate

• Large RCTs and recent population analyses confirm no increase in overall CS rate with neuraxial versus systemic opioid analgesia, irrespective of early initiation.
• Observational work of >500 000 births shows neuraxial analgesia is associated with a 35 % reduction in severe maternal morbidity (SMM), reinforcing its safety profile.

Instrumental Vaginal Delivery

• High-dose epidurals (>0.1 % bupivacaine-equivalent) increase assisted vaginal delivery (AVD).
• Network meta-analysis demonstrates that low/ultra-low LA or PIEB + PCEA regimens restore AVD rates to baseline.
• Encourage upright positioning and coached pushing to mitigate residual risk.

Fetal & Neonatal Outcomes

Variable	Finding	Evidence
Fetal heart rate (FHR) changes	Transient decelerations occur in up to 15 % after rapid-onset CSE, attributed to acute ↓ maternal catecholamines.	Usually resolve within 10 min; continuous CTG for 30 min post-dose.
Severe neonatal morbidity	No increase in 5-min Apgar < 7 or NICU admission with modern regimens.
Breast-feeding	Low-dose LA ± fentanyl epidurals do not impair initiation or duration of breast-feeding.

Technique Comparison

Combined Spinal–Epidural (CSE) & Dural-Puncture Epidural (DPE)

Aspect	CSE	DPE
Onset of analgesia	2-5 min (opioid ± 5 mg bupivacaine)	6-8 min, faster than standard epidural
Fetal effects	Higher incidence of transient bradycardia (up to 11 %).	Similar to epidural
Block quality/failure	Lowest failure rate; ideal for rapid progress	↓ unilateral & motor block compared with epidural.
Limitations	Can’t test epidural for 60-90 min; ↑ PDPH risk	Still investigational; requires pencil-point spinal needle

Continuous Caudal Analgesia

• Rarely employed owing to
  • Higher infection and misplacement risk, especially in advanced labour; documented rectal or foetal injections.
  • Large volumes (≥20 mL) needed for low-thoracic spread → ↑ maternal plasma LA concentrations.
    Remains a niche option (e.g., severe lumbar scoliosis/fusion).

Selecting the Optimal Technique

Technique	Preparation time	Analgesia quality & onset	Motor block	Conversion to CS anaesthesia
Epidural (PIEB ± PCEA)	Moderate	Excellent; titratable	Minimal with ≤0.1 % LA	May require 2-chloroprocaine top-up
CSE	Fast	Rapid & dense	Minimal (opioid-only SA)	Reliable with epidural top-up
DPE	Moderate	Near-CSE quality	Minimal	Similar to epidural
Continuous caudal	Slow	Variable	Minimal	Limited by cephalad spread

• Key take-away: Low-concentration LA techniques (PIEB + PCEA or DPE) maximise maternal satisfaction and safety while keeping instrumental and CS rates at baseline.

Complications

Complication	Updated incidence/notes	Prevention & management pearls
Hypotension after epidural initiation	≈ 10–15 % with low-dose solutions	Treat with 250 mL crystalloid coload and phenylephrine 50–100 µg IV; exclude intrathecal placement
Pruritus	Up to 30 % with lipophilic opioids	Ondansetron 4 mg IV or low-dose nalbuphine 2 mg IV effective; dexmedetomidine adjunct reduces incidence
Maternal fever	15–25 % after ≥4 h epidural; inflammatory rather than infectious	Paracetamol and active maternal cooling; antibiotics only if sepsis suspected
Shivering	Common with neuraxial block	Low-dose pethidine (meperidine) 12.5 mg IV or forced-air warming
Inadequate analgesia / catheter failure	6–12 % with ultrasound-guided placement; lower with combined spinal-epidural (CSE)	Re-site early; use ultrasound to confirm midline; consider DPE or CSE in difficult anatomy
Local anaesthetic systemic toxicity (LAST)	Inadvertent IV injection ≈ 1: 5000	Immediate 20 % lipid emulsion 1.5 mL kg⁻¹ bolus → 15 mL kg⁻¹ h⁻¹ infusion
Post-dural puncture headache (PDPH)	35–50 % after recognised Dural puncture using Tuohy needle	Early mobilisation acceptable; offer sphenopalatine ganglion block; epidural blood patch (EBP) 15–20 mL if debilitating
High or total spinal	1: 1400–16000	Call for help; left uterine displacement; vasopressors; airway control with ketamine 1.5 mg kg⁻¹ and suxamethonium 1 mg kg⁻¹ if apnoeic
Persistent motor block / prolonged neural deficit	Rare; rule out epidural haematoma (MRI <6 h)	Stop infusion, urgent imaging, neurosurgical referral

High (Total) Spinal Neuraxial Block

Definition & Incidence

• High spinal: Sensory block spreads above T3, producing clinically significant cardio-respiratory compromise.
• Total spinal: Unintentional large intrathecal dose produces brain-stem anaesthesia with apnoea and profound hypotension.
• Contemporary obstetric data (89 726 neuraxial cases, 2021-2023) estimate an incidence of 1: 3 100 for high/total spinal; 15 % require tracheal intubation.

Risk Factors

• Rapid or excessive intrathecal injection (e.g. epidural “top-up” inadvertently intrathecal).
• Short stature (<150 cm), obesity, late pregnancy.
• Supine or head-down positioning before block has fixed.
• Multi-orifice epidural catheter misplaced in subarachnoid, subdural or intradural space.
• Recent large epidural bolus (<30 min) followed by spinal or CSE.

Recognition (progressive timeline)

Time course	Respiratory signs	Cardiovascular signs	Conscious level
Early (T4–T2)	Dyspnoea, weak cough, RR 12–15 min⁻¹, SpO₂ ≥ 95 %	SBP ↓ 10–20 %, HR normal	Anxious but alert
Impending (C7–C5)	Hypoventilation, unable to speak, SpO₂ 90–95 %	SBP ↓ > 20 %, ± HR < 60 min⁻¹	Dizzy, paraesthesiae upper limbs
Established (C4 and above)	Apnoea	Severe hypotension ± bradycardia/asystole	Loss of consciousness

View or edit this diagram in Whimsical.

Management Algorithm

1. Call for help, tilt uterus left 15°.
2. 100 % oxygen; support ventilation with bag-mask ± cricoid pressure.
3. Secure airway if apnoeic/obtunded: ketamine 0.5 mg kg⁻¹ IV + suxamethonium 1 mg kg⁻¹ (avoid propofol/thiopental).
4. Circulation
   • Ephedrine 6–12 mg IV if HR < 60 min⁻¹.
   • Phenylephrine 100 µg IV if HR ≥ 60 min⁻¹ and SBP < 80 % baseline.
   • Adrenaline 10–20 µg IV for refractory hypotension or arrest; start infusion 0.05–0.1 µg kg⁻¹ min⁻¹ as needed.
5. Position head-up once haemodynamically stable to limit further cephalad spread.
6. Post-event imaging (MRI) if persistent neurological deficit > 6 h to exclude cord compression.

Post-Dural Puncture Headache (PDPH)

Background

• Definition: Orthostatic headache within 5 days of a recognised or occult dural puncture.
• Incidence: ~35 % after unintentional dural puncture (UDP) with a 16–18 G Tuohy; <1 % after pencil-point spinal.

Risk Factors

• Female sex; > age < 50 y; large cutting needle; bevel perpendicular to dura; multiple attempts; failure to replace stylet.

Presentation

• Onset: Typically develops 12-48 hours after dural puncture (up to 5 days).
• Duration: Usually resolves spontaneously within 1-2 weeks.
• Characteristics: Positional headache (worse when upright, better when supine), bilateral, often frontal or occipital.
• Associated Symptoms: Neck stiffness, photophobia, nausea, subjective hearing changes (tinnitus, hypoacusia).

Pathophysiology

• Mechanism: Thought to be due to CSF leakage through the dural hole, causing CSF or intracranial hypotension.

Differential Diagnosis

• Important to rule out other more sinister causes of headache.
• Indications for Urgent Imaging: CT/MRI, neuro consult if diagnosis is unclear, presence of fever/chills, neurological signs, seizures, decreased level of consciousness (LOC), or if two epidural blood patches (EBPs) are ineffective.

Management

Conservative

• Daily review until resolution.
• Bed rest for temporary relief.
• Maintain hydration.
• Thromboprophylaxis considering the timing if a blood patch is used.
• Simple analgesia.
• Stronger opioids (<72 hours) can be offered.
• Caffeine (200-300 mg doses, total 900 mg/24 hours) for short-term benefit.
• Stool softeners to avoid straining.

Epidural Blood Patch (EBP)

• Indications: If conservative measures fail or the headache is debilitating.
• Effectiveness: 65-98% effective after one treatment; can repeat if necessary.
• Contraindications: Same as those for neuraxial anesthetic techniques.
• Procedure:
  • Administer at the level or one level below the previous entry point.
  • Use 20 mL of blood, stopping if discomfort occurs.
  • No need for concomitant antibiotics.
  • Bed rest for 2 hours post-procedure.
  • Ongoing monitoring and review 4 hours after the procedure.

Other Options

• Trans-nasal sphenopalatine ganglion blocck (0.5 mL 2 % lignocaine per nostril).
• Greater occipital nerve block for refractory occipital pain.
• Imaging / neurology consult: Thunderclap onset, focal neurology, seizure, fever, or failure of two EBPs.

Prevention of PDPH

• Insufficient evidence for clear guidance.
• Consider injecting ~10 mL of preservative-free normal saline into the subarachnoid space if UDP occurs.
• Consider placing an intrathecal catheter for 24 hours, ensuring medications are not inadvertently injected into the catheter.

Spinal Hypotension

• SBP < 90 mmHg or > 2030 % fall from baseline (same for MAP).

Prevention Bundle (level A evidence)

Component	Details
Left uterine displacement	≥15° from time of spinal
Crystalloid coload	10–15 mL kg⁻¹
Phenylephrine infusion	Start 25–50 µg min⁻¹ immediately after intrathecal injection; titrate q1 min to keep SBP ≥ 90 % baseline
Alternative first-line	Norepinephrine 2–3 µg min⁻¹ ↓ bradycardia, ↑ CO (network meta-analysis 2025).

Rescue Algorithm

1. SBP 80–90 % baseline, HR ≥ 60 min⁻¹: Increase infusion or give phenylephrine 100 µg IV.
2. SBP < 80 % baseline + HR < 60 min⁻¹: Ephedrine 5–10 mg IV ± atropine 0.6 mg IV.
3. Refractory / HR < 50 min⁻¹: Adrenaline 10 µg IV bolus → infusion 0.05–0.2 µg kg⁻¹ min⁻¹.

• Resource-limited settings: intermittent boluses—phenylephrine 50–100 µg, ephedrine 10 mg, metaraminol 0.5 mg.

Prediction Tools

Tool	Variables	Notes
PRAM score	Age > 25 y, HR > 90 min⁻¹, MAP < 90 mmHg (0–3)	Score = 3 doubles hypotension risk; limited external validation.
Shock index ≥ 0.9	HR/SBP	Baseline SI ≥ 0.9 independently predicts post-spinal hypotension.

Regional for C/S

Single-Shot Spinal Anaesthesia

Component	Contemporary recommendations	Evidence
LA dose	Hyperbaric bupivacaine 0.5 % 9–12 mg (ED95 ≈ 11 mg; consider 8–9 mg in <150 cm stature)	Dose-finding RCTs 2023–24
Opioid adjuncts	Fentanyl 15–25 µg or sufentanil 5–10 µg → faster onset, denser block, no neonatal depression	Large meta-analysis 2022
Intrathecal morphine	100 µg (range 75–150 µg) prolongs analgesia to 18–24 h; monitor ≥ 12 h for delayed respiratory depression	ASA adjuvant statement 2024
Obesity considerations	110 mm (4.3 in) 25 G pencil-point needle suffices for most. Use 120–150 mm needle or pre-procedural ultrasound if BMI ≥ 40 kg m⁻².	RCTs 2023–25

• Hypotension prophylaxis
  Phenylephrine infusion 25–50 µg min⁻¹ from time of intrathecal injection halves the incidence of pre-delivery hypotension compared with boluses

Epidural Anaesthesia (Extension of Labour Epidural)

Urgency category	Suggested top-up	Onset (T4)	Notes
Elective / category III	Lidocaine 2 % + adrenaline 5 µg mL⁻¹ + sodium bicarbonate 1 mEq per 10 mL + fentanyl 100 µg; total 15–20 mL in 5 mL increments	5–7 min	Alkalinisation accelerates onset
Urgent / category II	Chloroprocaine 3 % 15–20 mL	2–3 min	Rapid metabolism; minimal neonatal exposure
Category I (immediate threat)	Consider spinal (8–10 mg bupivacaine + opioid) or GA if conversion uncertain

Best practice

• Aspirate + incremental dosing remain safer than routine test-dose; adrenaline test-dose reserved when surgical anaesthesia is imminent.
• Treat inadequate block early: additional 5 mL alkalinised lidocaine; if still patchy, proceed to CSE or GA.

Alternative Regional Techniques

Technique	Typical use	Key limitations
Paracervical block	Adjunct for first-stage pain when neuraxial unavailable	Risk of fetal bradycardia; seldom sole technique
Pudendal block	Perineal analgesia for instrumental/second stage	Haematoma, infection, pudendal neuropathy
Continuous caudal	Rare—spinal abnormalities	Higher infection & misplacement rates; large LA volumes required

“Walking” (Ambulatory) Epidural / CSE

• Low-dose CSE (e.g. bupivacaine 2.5 mg + fentanyl 25 µg intrathecal, followed by PIEB + PCEA ≤0.06 % bupivacaine) preserves motor power and allows ambulation when strict criteria are met. UK safety checklist (Hywel Dda UHB 2024) requires:

1. Reassuring CTG, engaged presenting part
2. Stable vitals (< 10 % change)
3. Modified Bromage 0; able to straight-leg raise and step unassisted
4. Continuous support & 15-min intermittent CTG monitoring

• Adherence to such protocols maintains mobility without increasing falls or instrumental delivery rates

Epidural Analgesia in VBAC

Concern	Evidence-based answer
Masks uterine rupture pain	Break-through pain (“epidural sieve”) combined with CTG changes detects rupture earlier than pain alone. Large cohort (> 1 500 VBACs) shows no delay in diagnosis.
Attenuates haemodynamic response to bleeding	Sympathectomy effect small; vigilance for unexplained hypotension still required
Safety	No increase in uterine rupture or neonatal morbidity; facilitates rapid conversion to surgical anaesthesia if needed

Troubleshooting an Epidural During Labour

1. Rule out non-neuraxial pain (bladder, cervical laceration, uterine rupture).
2. Check catheter position → re-site early if uncertain.
3. Top-up options
   • Dilute bolus 5–10 mL 0.1 % bupivacaine + 2 µg mL⁻¹ fentanyl.
   • For asymmetric block: place less-blocked side dependent, give incremental boluses.
4. Persistent failure or > 2 clinician boluses → re-site or convert to CSE.

Extending Epidural Labour Analgesia to Caesarean Anaesthesia

Step	Practical tip
Assess time since last dose	Treat as no block if > 60 min or multiple rescues required.
Plan drug & volume	Aim 15–20 mL to reach T4. Use alkalinised lidocaine or chloroprocaine for speed.
Monitor	Continuous BP, HR, SpO₂; phenylephrine infusion ready.
Failure to achieve dense block within 10 min	Perform spinal (preferred) or GA; do not delay for repeated epidural boluses.

Enhanced Recovery After Caesarean (ERAC)–2025 Update

• Why ERAC? Standardised, evidence-based care bundles shorten length of stay by ~12 h, halve moderate–severe pain scores, and reduce opioid use by 40 %.

Pre-operative Phase

Core elements (ERAS Society 2022)	Key details
Patient education & expectations	Written & video resources; discuss early mobilisation, feeding, analgesia
Limit fasting	Solids ≤ 6 h; clear carbohydrate drink (50 g) 2 h pre-op
Haemoglobin optimisation	Treat iron-deficiency anaemia ≥2 weeks pre-delivery; aim Hb ≥ 110 g L⁻¹
Breast-feeding preparation	Lactation counselling; skin-to-skin within 5 min of delivery

• Optional enhancements–smoking cessation, anxiety screening, birth companion training.

Intra-operative Phase

Core elements (Part 2 guideline)	Practical implementation
Prevent spinal hypotension	Phenylephrine 25–50 µg min⁻¹ (or norepinephrine 2–3 µg min⁻¹ if maternal HR < 60) from block placement
Normothermia	Forced-air warming + IV fluids warmed to 37 °C
Antibiotic prophylaxis	Cefazolin 2 g ≥ 30 min pre-incision (add metronidazole if prolonged rupture)
Nausea / vomiting (I- & PONV)	Ondansetron 4 mg IV + dexamethasone 8 mg IV
Multimodal analgesia start	Spinal morphine 100 µg; IV paracetamol 1 g; consider TAP block if spinal opioid omitted
Optimal uterotonics	Oxytocin 1–3 IU slow IV then infusion 7.5 IU h⁻¹; avoid ergometrine in hypertensive women
Immediate bonding	Skin-to-skin while on table; delayed cord clamping ≥ 60 s

• Recommended extras–goal-directed fluid therapy (2 mL kg⁻¹ h⁻¹ maintenance), cell-saving if anticipated blood loss > 1 L, liberal clear-fluid intake in theatre.

Post-operative Phase

Core elements (Post-op guideline 2025)	Targets
Early oral intake	Sips in PACU; full diet within 4 h
Early mobilisation	Sit up by 4 h; ambulate ≥10 m by 8 h
Urinary catheter removal	≤ 8 h if ambulating and no magnesium infusion
Multimodal analgesia	Regular paracetamol + NSAID (if normotensive & no PPH); breakthrough oxycodone 2–5 mg PO
VTE prophylaxis	LMWH 40 mg SC from 6 h & anti-embolism stockings
Anaemia remediation	IV iron if Hb < 100 g L⁻¹ 24 h post-op
Breast-feeding support	Dedicated nurse within first hour
Discharge	Criteria-led; goal ≤ 30 h post-op

• Recommended extras–glycaemic control < 8 mmol L⁻¹, chewing gum to hasten bowel function.

Neuraxial Analgesia & Anaesthesia in Pre-eclampsia (PET)

Consideration	Current best evidence
Platelet threshold	Safe to proceed if stable count ≥ 70 × 10⁹ L⁻¹; verify within 6 h in HELLP.
Labour epidural	Blunts pain-induced hypertension and catecholamine surges; facilitates rapid conversion to anaesthesia if urgent CS required.
Spinal / CSE	Lower incidence of severe hypotension in PET, but maintain phenylephrine (or NE) infusion readiness.
Vasopressor of choice	Phenylephrine first-line; norepinephrine offers less bradycardia and higher cardiac output.
Fluids	Restrict crystalloids; treat hypotension primarily with vasopressors (no autoregulation of uteroplacental flow).
Airway	Anticipate oedema–ramped position, 6 cm ETT, THRIVE/NODESAT for apnoeic oxygenation.
Drugs to avoid	Ergometrine; rapid IV oxytocin bolus (>3 IU); NSAIDs if renal or platelet dysfunction present.
Post-op	Higher PPH and pulmonary oedema risk–HDU/ICU observation for 24 h.

Dexmedetomidine as an Adjuvant in Neuraxial and Peripheral Regional Anesthesia: Updated Evidence and Guidelines (2020–2025)

Mechanism of Action

• α2-Adrenergic Agonism: Dexmedetomidine (DEX) exhibits high selectivity for α2 over α1 receptors (α2:α1 ≈ 8–10:1), leading to sedation, analgesia, and sympatholysis.
• Hyperpolarization via HCN Channel Blockade: DEX inhibits hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, enhancing analgesia and potentiating local anesthetic effects.
• Analgesia: Mediated through inhibition of substance P and glutamate release in the dorsal horn of the spinal cord.
• Sedation: Achieved by activation of α2 receptors in the locus coeruleus
• Vasoconstriction: Mild α1 activity may delay systemic uptake of local anesthetics, prolonging their effect.

General Safety

• Regulatory Status: DEX is not FDA-approved for obstetric use or non-intravenous routes.
• Pregnancy Category: Classified as Category C; crosses the placenta but results in minimal fetal exposure.
• Neonatal Outcomes: Studies report no significant changes in fetal heart rate, Apgar scores, or neonatal outcomes.
• Neurotoxicity: No reported neurotoxic effects with neuraxial or perineural administration

Clinical Applications and Dosing by Route

1. Intravenous (IV) Use in Obstetric Anesthesia

• Indications: Intraoperative sedation, analgesia, shivering control, and potential PTSD prevention.
• Dosing:
  • Sedation: Continuous infusion at 0.2–0.5 µg/kg/hr.
  • Shivering: Single bolus of 0.5 µg/kg.
• Benefits:
  • Minimal respiratory depression.
  • Reduced intraoperative pain in cesarean section patients.
  • Effective shivering control compared to alternatives like meperidine.
  • Potential reduction in PTSD incidence post-cesarean section.

2. Intrathecal Dexmedetomidine

• Proposed Mixture:
  • DEX: 2–4 µg (based on 4 µg/mL preservative-free vial).
  • Local Anesthetic: 10–13.5 mg of 0.75% hyperbaric bupivacaine.
  • Optional: Intrathecal morphine for extended analgesia.
• Outcomes:
  • Faster onset and prolonged duration of sensory and motor block.
  • Reduced postoperative pain and shiveriring
  • Decreased need for intraoperative opioids.
  • Potential for hypotension and bradycardia; preparedness with vasopressors and anticholinergics recommended.
• Evidence
  • A study determined the ED50 of intrathecal DEX as an adjuvant to plain ropivacaine for spinal anesthesia during cesarean section to be approximately 5.9 µg with 8 mg ropivacaine and 3.1 µg with 10 mg ropivacaine.

3. Epidural Dexmedetomidine

A. Epidural Conversion for Cesarean Section

• Mixture: 4 µg DEX added to 10–20 mL of 2% lidocaine, with or without bicarbonate.
• Outcome: Faster onset and improved intraoperative analgesia.

B. Epidural Top-Ups (Second Stage Labor)

• Mixture: 2–4 µg DEX added to standard bolus (e.g., 4 mL of 0.1% ropivacaine with fentanyl or 2–3 mL of 0.2% ropivacaine).
• Benefit: Enhanced assessment of block effectiveness and improved analgesia.

C. Continuous Labor Epidural Infusions

• Mixture: 0.1% ropivacaine with 0.3–0.5 µg/mL DEX.
• Outcomes:
  • Reduced local anesthetic consumption.
  • Decreased patient-controlled epidural analgesia (PCEA) boluses.
  • Lower incidence of pruritus and nausea.
  • No significant maternal or neonatal side effects.
  • Optimal concentration identified as 0.3 µg/mL to minimize motor block.
• Evidence:
  • A study found that dexmedetomidine combined with local anesthetic for epidural labor analgesia improved pain scores without prolonging labor stages

4. Peripheral Nerve Blocks

• Mixtures:
  • Outpatient Procedures: 0.5–1 µg/kg DEX with local anesthetic.
  • Inpatient Procedures: 1–2 µg/kg DEX with local anesthetic.
• Benefits:
  • Shortened onset time of anesthesia.
  • Prolonged analgesia by approximately 3–4 hours.
  • Opioid-sparing effect.
• Cautions:
  • Transient hypotension observed at higher doses (1.5–2 µg/kg).
  • Contraindicated in patients with bradycardia, hypotension, pulmonary hypertension, obstructive sleep apnea, frailty, or shock.
• Key Studies
  • A meta-analysis revealed that perineural DEX doses of 30–50 µg are appropriate, providing prolonged analgesia without increasing the risk of bradycardia and hypotension

5. Nebulized Dexmedetomidine for Post-Dural Puncture Headache (PDPH)

• Dose: 1 µg/kg diluted to 4 mL with saline, administered every 12 hours.
• Benefits:
  • Reduction in cerebral blood flow, alleviating PDPH symptoms.
  • Increased cerebrospinal fluid (CSF) pressure due to decreased absorption.
  • Non-invasive and opioid-sparing approach.
  • Minimal hemodynamic or sedative effects.

Dexmedetomidine as an Adjuvant in Regional Anesthesia

Route / Application	Dose / Concentration	Evidence Summary	Benefits	Comparisons / Notes
Intrathecal (CS, ortho)	2–4 µg+ 10–13.5 mg 0.75% bupivacaine ± morphine	Liu et al. 2020; Mo et al. 2023: prolonged block (~2h), reduced pain, ED50 ≈ 3.1–5.9 µg	Fast onset, dense and prolonged block, ↓ shivering, ↓ opioid need	Superior to fentanyl for block duration and shivering reduction
Epidural Conversion (CS)	4 µg + 10–20 mL 2% lidocaine ± bicarbonate	Riham et al. 2016: improved onset, analgesia vs epinephrine	Rapid CS conversion, better intra-op analgesia	Comparable or better than epinephrine
Epidural Top-Up (2nd Stage)	2–4 µg + 4 mL 0.1% ropivacaine ± fentanyl OR 2–3 mL 0.2% ropivacaine	Qian et al. 2021; Yang et al. 2020: faster onset, less nausea/shivering vs fentanyl	Improved block efficacy, less shivering and nausea	Faster onset and fewer side effects than fentanyl
Continuous Epidural Infusion	0.3–0.5 µg/mL in 0.1% ropivacaine	Wei et al. 2022; Pang et al. 2022: fewer PCEA boluses, lower LA use, optimal dose = 0.3 µg/mL	Longer duration, fewer PCEA uses, less pruritus	Better tolerability than sufentanil
Peripheral NB (Outpatient)	0.5–1 µg/kg + local anesthetic	Dai et al. 2018: prolonged block (~3–4h), better analgesia	Faster onset, prolonged analgesia, opioid-sparing	↑ bradycardia/hypotension vs ropivacaine alone
Peripheral NB (Inpatient)	1–2 µg/kg + local anesthetic	Packiasabapathy et al. 2017; Jung et al. 2018: 2 µg/kg superior to 1 µg/kg for duration (~20h)	Longest block duration (~20h), ↓ postop opioid use	2 µg/kg better than 1 µg/kg; ↑ hypotension risk
Nebulized (PDPH)	1 µg/kg diluted to 4 mL saline, q12h	Kumar et al. 2019; Mowafy et al. 2021: ↓ PDPH severity, increased CSF pressure, minimal side effects	Non-invasive PDPH relief, minimal sedation	Alternative to conservative PDPH management

Links

• Neuraxial and Epidural
• Neuraxial Ultrasound
• Obstetric physiology
• Maternal conditions
• Non obstetric surgery
• Opioid sparing adjuncts

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Past Exam Questions

Safety and Efficacy of Labour Analgesia Modalities

Critically evaluate the safety and efficacy of the following modalities for labour analgesia.
a) Remifentanil patient-controlled analgesia (PCA) pump. (5)
b) Single-shot spinal anaesthetic. (5)

Pain Pathways in Labour and Locoregional Techniques for Perineal Repair

a) Define the stages of labour and describe the transmission of nociceptive stimuli to the spinal cord (“pain pathways”) in each phase of labour as well as during caesarean section. (8)
b) A patient has a third-degree tear after vaginal delivery. List two locoregional techniques that may be used to facilitate a repair. (2)

Risks of Epidural Analgesia in Labour

You are obtaining consent for epidural analgesia from a parturient in labour.

Define and quantify 5 of the most pertinent risks of this procedure. (10)

Labour Epidural Consent and Risks

a) In consenting a patient for a labour epidural, how would you quantify the risks for the following complications:

• i) Temporary nerve damage. (1)
• ii) Permanent nerve damage. (1)
• iii) Dural puncture. (1)
• iv) Failure. (1)
  b) List three precautions that you would take to mitigate the risk of catheter migration. (3)
  c) A patient experiences pain during the second stage of labour despite a well-functioning epidural in the first stage. Give two reasons for this. (3)

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References:

1. Allman K, Wilson I, O’Donnell A. Oxford Handbook of Anaesthesia. Vol. 4. Great Clarendon Street, Oxford, OX2 6DP, United Kingdom: Oxford University Press; 2016. 1295 p. Allman et al. – Oxford Handbook of Anaesthesia.pdf
2. Butterworth J, Mackey D, Wasnick J. Morgan and Mikhail’s Clinical Anesthesiology, 7th Edition. 7th edition. New York: McGraw Hill Medical; 2022.
3. Volmanen, Petria; Palomäki, Outib; Ahonen, Jounic. Alternatives to neuraxial analgesia for labor. Current Opinion in Anaesthesiology 24(3):p 235-241, June 2011. | DOI: 10.1097/ACO.0b013e328345ad18
4. South African Medical Journal 2017;107(12):1127-1131. DOI:10.7196/SAMJ.2017.v107i12.123901. The Calgary Guide to Understanding Disease. (2024). Retrieved June 5, 2024, from https://calgaryguide.ucalgary.ca/
5. Bower, J. and Kinsella, S. (2020). Preventing and treating hypotension during spinal anaesthesia for caesarean section. BJA Education, 20(11), 360-361. https://doi.org/10.1016/j.bjae.2020.08.001
6. Bao, N., Shi, K., Wu, Y. et al. Dexmedetomidine prolongs the duration of local anesthetics when used as an adjuvant through both perineural and systemic mechanisms: a prospective randomized double-blinded trial. BMC Anesthesiol 22, 176 (2022).(https://doi.org/10.1186/s12871-022-01716-3)
7. Talke P, Anderson BJ. Pharmacokinetics and pharmacodynamics of dexmedetomidine-induced vasoconstriction in healthy volunteers. Br J Clin Pharmacol. 2018 Jun;84(6):1364-1372. doi: 10.1111/bcp.13571. Epub 2018 Apr 2. PMID: 29495085; PMCID: PMC5980451.(https://bpspubs.onlinelibrary.wiley.com/doi/10.1111/bcp.13571)
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16. Nazir N, et al. Trans-nasal sphenopalatine ganglion block for post-dural puncture headache: systematic review and meta-analysis. Br J Anaesth. 2023;131:1182-92. pubmed.ncbi.nlm.nih.gov
17. Lou S, et al. ED90 of epidural esketamine with 0.075 % ropivacaine for labour analgesia. Front Pharmacol. 2023;14:1169415. frontiersin.org
18. Brown CA, et al. Modern labour epidural analgesia and labour outcomes. Am J Obstet Gynecol. 2023;229:678-85. sciencedirect.com
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20. Sween LK, Xu S, Li C, O’Donoghue MA, Ciampa EJ, Kowalczyk JJ, Li Y, Hess PE. Low-dose intravenous dexmedetomidine reduces shivering following cesarean delivery: a randomized controlled trial. Int J Obstet Anesth. 2021 Feb;45:49-55. doi: 10.1016/j.ijoa.2020.11.004. Epub 2020 Nov 17. PMID: 33293185. (https://pubmed.ncbi.nlm.nih.gov/33293185/)
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22. Liu S, Zhao P, Cui Y, Lu C, Ji M, Liu W, Jiang W, Zhu Z, Sun Q. Effect of 5-μg Dose of Dexmedetomidine in Combination With Intrathecal Bupivacaine on Spinal Anesthesia:(https://pubmed.ncbi.nlm.nih.gov/32222361/) A Systematic Review and Meta-analysis. Clin Ther. 2020 Apr;42(4):676-690.e5. doi: 10.1016/j.clinthera.2020.02.009. Epub 2020 Mar 25. PMID: 32222361.
23. Khosravi F, Sharifi M, Jarineshin H. Comparative Study of Fentanyl vs Dexmedetomidine as Adjuvants to Intrathecal Bupivacaine in Cesarean Section: A Randomized, Double-Blind Clinical Trial. J Pain Res. 2020 Oct 7;13:2475-2482. doi: 10.2147/JPR.S265161. PMID: 33116789; PMCID: PMC7548853.(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7548853/#:~:text=In%20the%20present%20study%20intrathecal,compared%20to%2025%20%CE%BCg%20fentanyl.)
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Summaries
Labour Analgesia
Regional complications
Post dural puncture headache

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© 2025 Francois Uys. All Rights Reserved.

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