Conversion of labour epidural analgesia to surgical anaesthesia for emergency

Caesarean section

Dr. A. Patil

Consultant Anaesthetist

University Hospitals Coventry and Warwickshire

Anaesthetic involvement : 61% of total deliveries

Caesarean section: 30%

2018 -2019: Emergency LSCS under epidural : 25.9%

• Common practice to ‘top-up’ existing labour epidural to provide surgical anaesthesia for emergency LSCS

• Injection of concentrated local anaesthetic solution + adjuncts

• Successful neuraxial anaesthesia is measure of quality of care:• Successful labour analgesia• Limits the use of general anaesthesia

• RCOA recommendation • Decision to delivery time in > 90% cases

• Cat1 LSCS < 30min and Cat2 LSCS < 75min• Conversion from neuraxial to GA

• Cat 1 LSCS < 15% and Cat 1-3 < 5%

• Online OAA survey, 2017• Decision to top-up epidural for Cat 1and 2 LSCS• Response rate 41% (n=710)

• Consultants: 79.3%• Associate specialists: 1.4%• Staff grades: 4.4%• Trainees: 4.9%

• Factors influencing the decision to ‘top-up’ the epidural• Effectiveness of epidural for labour analgesia(99%),Category of LSCS(73%), Level of

blockade(61%)

• Factors influencing further management in case of failed top-up• Category of LSCS, dermatomal level of blockade, maternal airway

• Choice of further management: repeat epidural/CSE/ spinal/GA• Spinal anaesthesia was the commonest choice

• If repeat regional: What dose?• Reduced dose if the block is high

• Principles for safe conversion of epidural analgesia to surgical anaesthesia

Is the epidural good enough for top-up?(Assessment of the quality of block)

• Speak to the patient and midwife

• Is it providing adequate analgesia? Looks comfortable

• Is she still using Entonox?

• Breakthrough pain

• Epidural boluses given: Dose, frequency, time

• Was the epidural re-sited?

• Assess the block: Missed segments, Unilateral block

• Displacement, disconnection, pooling of solution under dressing

• In the delivery room before decision of em LSCS • Early recognition of poorly functioning epidural: manipulation or resiting

• Slow progress or concerns about CTG: anaesthetist must evaluate the effectiveness of epidural

• In theatre after decision to proceed to LSCS• Inspection of the site of epidural catheter

• If sufficient time is available: test the function by administering 1/4th -1/3rd LA dose: test every 3-5min, density and level of block

• In absence of evidence progression of block: DO NOT administer more than ½ of the LA solution

Reducing the risk of failure of epidural top-up(BJA education)

Where should I do the top-up?

• Labour room Vs Theatre

• Top-up in the room may decrease decision to delivery time

• Top-up in theatre allows continuous monitoring of mother and foetus and early identification of complications

• Follow the local Trust policy

• Be safe

• Always stay with the patient after top-up of epidural.

Should I use a test dose?(Confirmation of the correct location of epidural catheter)

• Area of controversy

• Important to confirm the location of epidural catheter • Avoid intravascular injection and LA systemic toxicity

• Injection into CSF resulting in high or total spinal anaesthesia

• Multi-compartmental block.

• Gentle aspiration of catheter for examining CSF or blood

• Test dose: LA +/- adrenaline (quick onset of block, hypotension, tachycardia)

• Need of test dose balanced against the delay for LSCS to commence.

• Follow local policy

What LA should I use for top-up?(Choice of LA and adjuncts)

• Choice of LA focuses on the need of• Speed of onset• Quality of block

• Mixture of• Local anaesthetic +/- adrenaline (Lidocaine, levobupivacaine, ropivacaine)• Opioid• +/- Bicarbonate

• Quickmix: 20mls of 2% lidocaine +1ml of 8.4% sodium bicarbonate + 0.1ml of 1:1000 adrenaline

• DO NOT exceed the maximum dose for the patient

• Local anaesthetic• Lidocaine + adrenaline has fastest onset of surgical anaesthesia• Ropivacaine: lowest need for intra-op supplementation• Bupivacaine and levobupivacaine: least effective solutions

• Opioids• Fentanyl: 50-100mcg• Decrease the time of onset of block• Increase the density of block

• Bicarbonate• Facilitates alkalinisation, increased concentration of unionised LA, easily cross the

neuronal membranes, quick onset• Possibly increases lipid solubility of fentanyl• Should NOT be added to bupivacaine, levobupivacaine and ropivacaine

• Adrenaline• Vasoconstriction: Decreases systemic absorption of LA, increases duration of action

Is it working enough?(Evaluation of adequacy of neuraxial blockade)

• Pelvic organs innervation: T10-L1

• Intra-abdominal plexus and greater splanchnic nerves upto T5

• Sensory Blockade:• Upper level

• National survey in 2010

• Common practice: Loss of sensation to cold and pinprick below T4 (sensitivities of 12% and 55%).

• Cold > Pinprick > Touch

• Lower level: S5

• Motor Block: Bromage Score

What do I do when the block is inadequate after top-up?Management of failed epidural top-up

• Inform the patient/ partner• Communicate to theatre staff and

obstetrician ?On LW if cat 2

• Is there time? • CTG?• Ask for help

What do I do when the block is inadequate after top-up?Management of failed epidural top-up

• Block not high enough or unilateral? Is it slow to come up?• Head low/ lateral tilt, more LA if maximum dose not reached

• If above is not suitable/ fails:

• Re-site or manipulate epidural

• CSE

• Spinal

• General anaesthesia

Drawbacks and risks (BJA education)

Manipulation or re-site epidural

• Time consuming

• Potential LA systemic toxicity with further administration of LA

CSE

• Time consuming

• Potential LA toxicity

• Difficult to choose optimal intrathecal dose

• Untested epidural catheter

Drawbacks and risks

Spinal

• Difficulty in obtaining CSF

• Difficult to select optimal intrathecal dose

• Failed spinal if low dose used

• Potential high or total spinal

General anaesthesia

• All the complications of GA : (separate topic)

What do I do when the patient complains of pain during surgery?

• Is it at incision, fundal pressure, exteriorisation of uterus, closure?

• Ask what sensation is she experiencing?• Sharp pain/ pressure/ touch

• Reassure if it’s pressure/ touch

• Offer GA

• Consider further topping-up epidural if time permits

• Document

Post-operative management

• Analgesia• Epidural diamorphine + oral analgesics

• Remove epidural catheter unless need for continuing with infusion

• Document the removal

• Prescribe appropriate thromboprophylaxis

• Post-op destination

Remember

• Team brief

• WHO checklist

• NRFit equipment

• Keep IV and epidural drugs separate

• Confirm that you are injecting LA into Epidural Catheter and NOT IV line

Epidural Top-up and COVID-19

• Important to assess the block to avoid GA

• Early re-site if not working

• Follow local policy for a theatre case (PPE, donning, doffing)

• If in doubt, do spinal

• Have help available