Labour Analgesia: First-Line Neuraxial Regimen

Continuous epidural infusion with low-dose local anesthetic (bupivacaine 0.0625–0.125% or ropivacaine 0.1–0.2%) combined with fentanyl 2–2.5 µg/mL is the recommended first-line technique, delivered via patient-controlled epidural analgesia (PCEA) with or without a background infusion, because it provides superior pain relief while minimizing motor block and reducing anesthetic interventions. 1

Drug Choices and Concentrations

Local Anesthetic Options

Bupivacaine 0.0625–0.125% (0.625–1.25 mg/mL) is the standard local anesthetic for labour epidural maintenance. 1
Ropivacaine 0.1–0.2% (1–2 mg/mL) is an equivalent alternative that provides comparable analgesia with similar motor-sparing properties. 2, 3
Do not exceed bupivacaine 0.125% for maintenance infusions, as higher concentrations increase motor block without improving analgesia and may impair maternal pushing. 2

Opioid Adjunct (Mandatory)

Fentanyl 2–2.5 µg/mL must be added to the local anesthetic solution to reduce the required local anesthetic concentration, improve analgesic quality, and minimize motor block. 1, 2
Sufentanil 0.75–1 µg/mL may be substituted for fentanyl when faster onset or more profound analgesia is desired. 2
Adding an opioid is not optional—it is essential for achieving adequate analgesia with dilute local anesthetic concentrations. 1

Test Dose

Administer 3–5 mL of a short-acting local anesthetic solution containing epinephrine before inducing complete block to detect intravascular or intrathecal catheter misplacement. 1
Maximum safe test dose is 10 mg bupivacaine equivalent (e.g., 2 mL of 0.5% bupivacaine), which produces detectable sensory, motor, or autonomic changes if intrathecal while minimizing the risk of high or total spinal anesthesia. 2
Repeat the test dose if the patient is repositioned in a manner that could displace the epidural catheter. 1
Allow adequate time for onset of anesthesia following each test dose before proceeding. 1

Initial Loading Dose

Bupivacaine 1.25–2.5 mg combined with fentanyl 12.5–25 µg is the recommended initial intrathecal dose for combined spinal-epidural (CSE) technique. 2, 4
For epidural-only technique, administer 10–15 mL of bupivacaine 0.1–0.125% with fentanyl 2–2.5 µg/mL as the loading dose. 2
Limit fentanyl to ≤15 µg in the initial epidural bolus for women in active labour to reduce pruritus, nausea, and respiratory depression without sacrificing analgesia. 2

Maintenance Infusion Settings

Patient-Controlled Epidural Analgesia (PCEA) – Preferred Method

PCEA is strongly preferred over fixed-rate continuous infusion alone because it reduces total local anesthetic consumption, decreases motor blockade, and requires fewer anesthetic interventions. 1, 2

PCEA Configuration Options

Parameter	Option 1: PCEA with Background	Option 2: PCEA without Background
Background infusion	8–10 mL/h of bupivacaine 0.0625–0.10% + fentanyl 2 µg/mL	None
PCEA bolus	5 mL	5–8 mL
Lockout interval	10–15 minutes	10–15 minutes
Maximum hourly volume	15–20 mL total/h	Determined by total bolus volume

1, 2

Both configurations are endorsed by the American Society of Anesthesiologists, allowing flexibility based on institutional protocols and patient needs. 1, 2

Continuous Infusion Alone (If PCEA Unavailable)

Bupivacaine 0.0625–0.125% with fentanyl 2–2.5 µg/mL at 10–12 mL/hour may be used when PCEA is not available. 2
Recognize that continuous infusion alone results in higher local anesthetic doses and increased motor block compared to PCEA. 1

Monitoring Parameters

Immediate Post-Initiation Monitoring (First 30 Minutes)

Measure maternal blood pressure every 5 minutes for at least the first 15 minutes after any epidural bolus. 1, 4
Continuous fetal heart-rate monitoring for 30 minutes after analgesia initiation is mandatory. 1, 4
An anesthetist must remain present with the patient for at least 10 minutes following the initial bolus. 4

Ongoing Labour Monitoring

Assess motor block hourly using the straight-leg-raising test (ability to lift the heel off the bed against gravity). This is the primary monitor of spinal cord health and takes priority over sensory block assessment. 1, 2, 5
Assess sensory block level hourly alongside motor testing. 1
If the patient cannot perform straight-leg raising, alert the anesthetist immediately, as this may signal catheter misplacement, excessive block, or neurologic compromise. 1, 5
Motor block assessment must not be replaced solely by sensory block monitoring. 1, 5

Recovery Monitoring (Post-Delivery)

Test for straight-leg raising ability at 4 hours after the last epidural or spinal dose. 5
Inability to straight-leg raise at 4 hours is a red flag requiring immediate anesthesiologist evaluation to rule out epidural hematoma or other complications. 5
Normal motor recovery occurs 2–3 hours after intrathecal bupivacaine and 3–5 hours after epidural bupivacaine. 5

Management of Breakthrough Pain

First, verify that the patient is using the PCEA correctly before administering additional doses. 1, 2
Administer a clinician-administered bolus of 1–2 mL of the same maintenance solution if analgesia is inadequate. 2, 4
If pain persists after the first bolus, increase the background infusion rate by 1 mL/h rather than delivering repeated boluses. 4
Persistent inadequate analgesia after dose adjustment indicates probable catheter malposition; the catheter should be removed and re-sited. 4
Never use a more concentrated local anesthetic solution for breakthrough pain, as this increases motor block and eliminates ambulation capability. 4

Common Complications and Management

Hypotension

Hypotension occurs in approximately 8–10% of patients receiving neuraxial labour analgesia. 6, 7
Treat with 6 mg intravenous boluses of ephedrine as needed. 6
Routine preloading with intravenous fluid is not required before initiating neuraxial analgesia. 1

Pruritus

Pruritus is significantly more common with CSE (41.4%) than epidural-only (1.3%) techniques due to intrathecal opioid administration. 7
Manage with antihistamines or low-dose naloxone infusion if severe. 7

Nausea and Vomiting

Nausea (2.4%) and vomiting (3.2%) are more frequent with CSE than epidural-only technique (1.0% each). 7
Treat with antiemetics (e.g., ondansetron, metoclopramide). 7

Post-Dural Puncture Headache (PDPH)

Use pencil-point spinal needles instead of cutting-bevel needles to minimize PDPH risk. 1
PDPH incidence is 2.3% with CSE using pencil-point needles. 6
Unintended dural puncture with an 18-gauge epidural needle occurs in 4.2% of epidural-only versus 1.7% of CSE techniques. 7
Manage PDPH with conservative measures initially; epidural blood patch is indicated for moderate to severe postural headache. 7

Motor Block

Significant motor block can occur even with low-dose regimens, although less commonly than with traditional higher-dose techniques. 1
Profound, progressive combined motor-and-sensory block is unusual with modern low-dose approaches. 1
If motor block prevents straight-leg raising at any hourly assessment, alert the anesthetist immediately. 1, 5

Epidural Hematoma (Time-Critical Emergency)

Epidural hematoma can cause irreversible neurological injury if not evacuated within 8–12 hours of symptom onset. 5
Risk factors include coagulopathy, anticoagulant use, multiple puncture attempts with bleeding, pre-existing spinal pathology, and sepsis. 5
Urgent MRI of the spine is the preferred imaging modality if epidural hematoma is suspected. 5
Emergency surgical decompression is required if hematoma is confirmed. 5

Technical Considerations

Combined Spinal-Epidural (CSE) vs. Epidural-Only

Both CSE and epidural-only techniques are acceptable first-line options; CSE provides faster onset of analgesia (3–5 minutes) while epidural offers comparable overall pain relief with lower pruritus incidence. 4, 7
CSE is especially indicated when cervical dilation is ≥6 cm or when immediate pain relief is required. 4
Epidural-only analgesia results in markedly lower pruritus rates (≈1% vs ≈41%) compared to CSE. 4

Timing of Initiation

Neuraxial analgesia should be offered on an individualized basis regardless of cervical dilation; there is no minimum dilation threshold. 1
Early epidural insertion (cervical dilation <5 cm) is appropriate when the patient requests it. 1
Reassure patients that neuraxial analgesia does not increase the incidence of cesarean delivery. 1

Early Catheter Placement in High-Risk Patients

In complicated parturients (e.g., twin gestation, preeclampsia, anticipated difficult airway, obesity), place an early neuraxial catheter before labour onset or before analgesia is requested to reduce the need for emergency general anesthesia. 1

Common Pitfalls to Avoid

Do not withhold neuraxial analgesia based on cervical dilation; the decision should be individualized and not tied to a specific dilation threshold. 1
Do not use higher concentrations of local anesthetic (>0.125% bupivacaine) for maintenance, as this increases motor block without improving analgesia. 1, 2
Do not rely solely on continuous infusion when PCEA is available, as this results in higher local anesthetic doses and more motor block. 1, 2
Do not substitute sensory-block monitoring for motor-block assessment; leg-strength testing remains the critical indicator of neurologic safety. 1, 5
Do not attribute prolonged motor block (>24 hours) solely to expected effects of local anesthetic, as this may delay diagnosis of serious complications such as epidural hematoma. 5
Do not use opioid agonist-antagonist agents (e.g., nalbuphine, butorphanol) in opioid-dependent women receiving medication-assisted treatment, as this may precipitate withdrawal. 4

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