[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anaesthesia and ICU](https://durgical.com/en/anaesthesia/) › [Regional anaesthesia](https://durgical.com/en/anaesthesia/areas/regional/) › Epidural anaesthesia and analgesia

# Epidural anaesthesia and analgesia

- Technique

A thin tube placed just outside the covering of the spinal cord carries numbing medicine for hours or days, for surgery, labour or pain after operations.

Updated Nov 13, 2026

## Key points

- Loss of resistance to saline or air marks entry into the epidural space after the ligamentum flavum.
- Slower onset and larger volumes than spinal; the catheter allows top-ups and infusions.
- Block is segmental: insert at the level of the incision (thoracic for chest and upper abdomen, lumbar for labour).
- Test dose, aspiration and incremental dosing detect intravascular or intrathecal catheters.
- An accidental dural puncture with the large epidural needle carries a high risk of headache.

On this page

- The basics Key points
- What it is
- Indications
- Equipment and preparation
- Step by step (and why)
- Spinal compared with epidural
- Next step
- Memory aid
- Elsewhere in DurgiPedia

- Clinical Complications

- Safety Contraindications and precautions

- Study Test yourself

- Connections Connections

## What it is

Epidural anaesthesia places local anaesthetic, often with an opioid, into the epidural space, the fat- and vein-filled space between the ligamentum flavum and the dura. Because the drug must spread through this space and cross the dura and nerve root sleeves, onset is slower than a spinal and larger volumes are needed. A catheter is usually threaded through a blunt curved-tip needle and left in place, so the block can be extended, topped up or run as a continuous infusion for hours or days. The block is segmental: it spreads up and down from the level of insertion, so a thoracic catheter can cover the chest or upper abdomen while sparing the legs. The space is found by the loss-of-resistance technique: as the needle passes the dense ligamentum flavum, pressure on a syringe of saline or air suddenly gives way. Low concentrations give analgesia with little motor block, used in labour and after thoracic, abdominal and major orthopaedic surgery; higher concentrations give surgical anaesthesia. A test dose and incremental injection guard against the catheter lying in a vein or in the subarachnoid space.

## Indications

- Labour analgesia, which can be extended to anaesthesia for caesarean section through the same catheter.
- Analgesia after thoracic and major upper abdominal surgery (thoracic epidural).
- Surgical anaesthesia for lower abdominal, pelvic or lower limb surgery, alone or with general anaesthesia.
- Combined spinal-epidural: fast spinal onset with the option to prolong it through the catheter.
- Patients with severe lung disease, where good analgesia improves coughing and breathing after surgery.

## Contraindications and precautions

- Absolute: patient refusal, infection at the site, raised intracranial pressure, and severe uncorrected hypovolaemia.
- Coagulopathy, low platelets and anticoagulants: time insertion and catheter removal by each drug's rules.
- Fixed cardiac output lesions: a slow, titrated epidural is gentler than a single-shot spinal but still needs care.
- Sepsis, spinal deformity, previous spine surgery and pre-existing neurological deficits need individual judgement.
- A patient who cannot cooperate or stay still during insertion raises the risk of dural puncture and nerve injury.

## Equipment and preparation

- Consent, intravenous access and standard monitoring; vasopressors and resuscitation equipment ready.
- Full sterile technique: antiseptic, drape, gown, gloves, mask and hat.
- Epidural needle with a blunt curved tip (for example 16- or 18-gauge) marked in centimetres, and a catheter with a filter.
- Loss-of-resistance syringe filled with saline or air.
- Local anaesthetic and opioid solutions labelled for epidural use only; an infusion pump with a dedicated, labelled line.

## Step by step (and why)

- Confirm consent, anticoagulant timing and platelets when relevant — a haematoma under the cord can cause paraplegia.
- Start monitoring and secure intravenous access — hypotension or toxicity may need treatment within seconds.
- Position sitting or lateral with the back flexed and choose the interspace for the surgery — the block spreads from that level.
- Prepare the skin aseptically and infiltrate local anaesthetic — infection of the space is rare but serious.
- Advance the needle with constant pressure on the syringe until resistance is suddenly lost — this marks the epidural space.
- Thread the catheter a few centimetres into the space and remove the needle — too deep and it may exit a foramen or enter a vein.
- Aspirate, then give a test dose and watch — blood, fluid, a rising heart rate or rapid leg block warn of a misplaced catheter.
- Give the main dose in small increments and check the level — divided doses limit toxicity and hypotension.
- Secure and label the catheter and the line — wrong-route injection of an intravenous drug or vice versa is a known error.
- Assess the block, blood pressure and sedation regularly — catheters migrate and blocks wear off or spread.

## Spinal compared with epidural

| Feature | Spinal | Epidural |
| --- | --- | --- |
| Space | Subarachnoid (cerebrospinal fluid) | Epidural (outside the dura) |
| Needle | Fine pencil-point | Larger, blunt curved tip |
| Endpoint | Free flow of fluid | Loss of resistance |
| Onset | Minutes | Slower |
| Volume of drug | Small | Larger |
| Duration | Single shot, fixed | Extendable through a catheter |

## Complications

- Hypotension from sympathetic block, slower in onset than with a spinal.
- Failed, patchy or one-sided block, often from catheter position; it may need withdrawal or re-siting.
- Accidental dural puncture with post-dural puncture headache; injection through it can cause a high or total spinal block.
- Intravascular injection causing local anaesthetic systemic toxicity; respiratory depression and itching from opioids.
- Rare but serious: epidural haematoma or abscess with cord compression, and nerve injury.

## Next step

- Record depth of the space, catheter length in the space, test dose result and block level.
- Hand over the epidural to the ward with a clear plan: monitoring, who to call, and when the catheter may be removed.
- Call a senior for signs of toxicity, a block spreading too high, or new leg weakness that does not fit the infusion.
- Stop the infusion and get an urgent scan and surgical review for back pain with new weakness, numbness or bladder change.
- Remove the catheter only when anticoagulant timing allows, and check the tip is intact.

## Memory aid

Aspirate, test, increment: every epidural top-up is a possible intravenous or intrathecal dose.

## Test yourself

Think of the answer, then tap the question to see it.

## How is the epidural space identified during insertion?

By loss of resistance: pressure on a syringe of saline or air resists while the needle is in the ligamentum flavum, then suddenly gives way as the tip enters the epidural space.

## Why is an epidural inserted at a thoracic level for an upper abdominal operation?

The block is segmental and spreads from the level of insertion, so a thoracic catheter covers the incision dermatomes and spares the legs and much of the sympathetic chain.

## What is the purpose of a test dose through an epidural catheter?

To detect a catheter in a vein (rising heart rate or toxicity symptoms) or in the subarachnoid space (a fast, dense spinal block) before the full dose is given.

## What does new back pain with leg weakness after an epidural suggest?

A possible epidural haematoma or abscess compressing the cord or roots; stop the infusion, get urgent imaging and a surgical opinion, as outcome depends on speed of decompression.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anaesthesia/epidural-anaesthesia-and-analgesia/)

## Elsewhere in DurgiPedia

- [Patient-controlled and epidural analgesia: the nursing checks](https://durgical.com/en/nursing/patient-controlled-and-epidural-analgesia-the-nursing-checks/)
- [Clean and sterile technique: medical and surgical asepsis](https://durgical.com/en/nursing/clean-and-sterile-technique-medical-and-surgical-asepsis/)
- [Pain and temperature: pathways and modulation](https://durgical.com/en/physiology/pain-and-temperature-pathways-and-modulation/)
- [Lumbar puncture](https://durgical.com/en/clinical-skills/lumbar-puncture/)

## Connections

## Related 6

- [Spinal anaesthesia](https://durgical.com/en/anaesthesia/spinal-anaesthesia/)
- [Complications of neuraxial blocks: headache, hypotension, haematoma, infection](https://durgical.com/en/anaesthesia/complications-of-neuraxial-blocks-headache-hypotension-haematoma-infection/)
- [Labour analgesia](https://durgical.com/en/anaesthesia/labour-analgesia/)
- [Local anaesthetic systemic toxicity: the crisis](https://durgical.com/en/anaesthesia/local-anaesthetic-systemic-toxicity-the-crisis/)
- [Anticoagulants, antiplatelets and neuraxial blocks](https://durgical.com/en/anaesthesia/anticoagulants-antiplatelets-and-neuraxial-blocks/)
- [Postoperative pain: multimodal analgesia](https://durgical.com/en/anaesthesia/postoperative-pain-multimodal-analgesia/)

## Related conditions 2

- [Local anaesthetic systemic toxicity (LAST)](https://durgical.com/en/conditions/local-anaesthetic-systemic-toxicity/)
- [Spinal epidural abscess](https://durgical.com/en/conditions/spinal-epidural-abscess/)

## In Pharmacology 6

- [Local anesthetics](https://durgical.com/en/pharmacology/classes/local-anesthetics/)
- [Bupivacaine](https://durgical.com/en/pharmacology/bupivacaine/)
- [Ropivacaine](https://durgical.com/en/pharmacology/ropivacaine/)
- [Lidocaine](https://durgical.com/en/pharmacology/lidocaine/)
- [Fentanyl](https://durgical.com/en/pharmacology/fentanyl/)
- [Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/)

[← All of anaesthesia](https://durgical.com/en/anaesthesia/)

Educational content; it does not replace supervised training, your institution's protocols or the anaesthetist's or intensivist's decision. It contains no doses and no ventilator or infusion settings.

Sources: [Epidural Anesthesia](https://www.ncbi.nlm.nih.gov/books/NBK542219/) (StatPearls (NCBI Bookshelf), 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anaesthesia/epidural-anaesthesia-and-analgesia/