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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