Epidural Troubleshooting

This covers management of the working and non-working epidurals. Insertion of an epidural and the particulars of the labour epidural are covered elsewhere.

Management of a Working Epidural

Maintenance of analgesia can be performed via:

• Intermittent boluses alone
  Essentially a historical relic.
• Continuous infusion with intermittent boluses
• Patient Controlled Epidural Analgesia (PCEA)

In general, maximal anaesthetic doses should be:

• Ropivacaine 3-4mg.kg^-1.6 hours^-1
• Bupivacaine 2-3mg.kg^-1.6 hours^-1
• Reducedin:
  • Hepatic failure
  • Renal failure
  • Severe hypoalbuminaemia

Continuous Infusion

• Typically lower concentrations used to minimise motor block
  • Ropivacaine 0.2%
  • Bupivacaine 0.0625-0.125%
• Generally run at 6-10ml/hr
• May have 5ml boluses Q20min
• Adjuvants include:
  • Opioid
    Classically fentanyl.
  • Adrenaline

Patient Controlled Epidural Analgesia

• May be run with a background infusion
• Reduced need for intervention
• e.g. Ropivacaine 0.2% with 2μg/ml fentanyl:
  • 5ml patient demand bolus, Q15 minute lockout

Catheter Removal

Removal of an epidural can occur when:

• Coagulation status is normal
  Covered under coagulopathy.
• No longer therapeutically indicated
• Risk of infection is too high to justify ongoing use Typically epidurals may stay up to 5 days following insertion, though local procedure may vary.
  • This needs to be balanced against the requirement for ongoing analgesia

Removing the catheter:

• Remove dressing
• Apply gentle pressure to remove the catheter
• Tip of catheter should be visible
• If catheter does not come out easily
  Place the patient in the same position they were in for insertion, and pull gently.

Troubleshooting an Epidural

Common issues include:

• High Block
• Inadequate analgesia
  • Patchy block
  • Asymmetric block
  • Diminished block
• Inadequate perineal analgesia

High Block

Symptoms include:

• Nasal stuffiness
• Difficulty breathing
• Lightheadedness
• Horner’s Syndrome
  
  • May occur following blockade of sympathetic ganglion of T1-4
  • Occur commonly with epidural top-up for LUSCS
    Of itself, not of clinical significance.

Treatment is based upon symptoms:

• Hypotension
  Vasopressor, such as metaraminol.
• Bradycardia
  Atropine.
• Hypoxia
  Supplemental oxygen, respiratory support.

Inadequate Analgesia

Can be defined as:

• Pain > 5
• Inability to cough or move effectively

May be associated with:

• Patchy block
• Asymmetric block
• Diminishing analgesia

Management process:

• Assess vitals
• Exclude surgical cause of pain
• Check pump on and working correctly
• Check catheter is connected
• Check catheter location
  Catheter may migrate out of the epidural space.
  • Check anticoagulation status prior to manipulation
• Check BP
  Hypotension and uncorrected hypovolaemia are relative contraindications to epidural bolus.
• Assess block
  • Patchy
  • Asymmetric
  • Dimishing analgesia

Patchy Block

• Immediately patchy blocks may be misplaced; consider replacing
  e.g. subdural, paravertebral, threaded over nerve root.
• Bolus with a moderately concentrated solution
  e.g. 0.125-0.25% bupivacaine.

Asymmetric/Unilateral Block

Generally indicates catheter is too far within the space:

• Withdraw catheter by 1cm and bolus
  Place in lateral position (un-blocked side down) to improve onset of block
• Catheter can be pulled back up to 3cm within the space

Diminishing Analgesia

A rescue bolus of LA can be delivered to re-establish a failing epidural. * Ensure adequate monitoring * Ensure working IV access * Ensure vasopressor is readily available * Give a rescue bolus
The end point is either analgesia or side effects. * Appropriate agents include: * 0.25% bupivacaine
6-10ml is appropriate for most adult patients, though more will sometimes be required. * Ropivacaine 0.35% * Ropivacaine 0.2% * If analgesia is achieved: * ↑ rate by one-third * Change solution * If no block to ice is present: * Consider alternate methods of analgesia

Inadequate Perineal Analgesia

Perineal analgesia is important at time of delivery. Block can be augmented with:

• LA bolus
  
  • 6-8ml of 0.125% bupivacaine
  • 3-4ml of 0.25% bupivacaine
• Fentanyl
  50-100μg augments analgesia without providing motor block.
• Position in semi-Fowler’s
  Enhances perineal analgesia from epidural.

Dosing for forceps delivery or episiotomy:

• Requires dense blockade with concentrated LA
• Consider:
  • 1-2% lignocaine
  • 0.25-0.5% bupivacaine

Neurological Injury

Can be divided into:

• Anaesthesia/epidural related
• Obstetric/surgery related

Anaesthesia Related

Anaethetic-related neurology includes:

• Prolonged neural blockade
  • May last 10-48 hours
    
  • Ultimately resolves
• Bladder dysfunction
  Associated with:
  • Urinary retention due to epidural anaesthesia
    Can be avoided with IDC.
• Direct trauma/neuritis
  • May occur from intraneural injection of LA
  • Leads to paraesthesia/sensory/motor loss in a specific dermatomal distribution.
• Epidural haematoma
  • Rare
    ↑ risk with coagulopathy.
• Epidural abscess/meningitis
  Key features:
  • Severe back pain
  • Local tenderness
  • Fever
  • Leukocytosis
• Adhesive arachnoiditis
• Anterior spinal artery syndrome

Obstetric/Surgery Related

Obstetric neurology:

• Occurs in 1:2400-6500
• Associated with:
  • Prolonged labour
  • Forceps delivery
• Typically causes neurology in a peripheral nerve distribution

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References

1. Don’t Panic! The Registrars Guide to the Epidural. Miles L, Christelis N.