Download Anaesthesia for Caesarean Section

Anaesthesia for Obstetric
Surgical Procedures
September 2010
Retained placenta
• Sensory block to T10 required
• Spinal/existing epidural
• Patient potentially hypovolaemic
Repair of perineal tear
• Spinal/existing epidural
• Good quality saddle block required
• Potentially hypovolaemic patient
Anaesthesia for Cervical Suture
• 1st/2nd trimester
• Spinal/GA
• If GA
– Avoid prolonged exposure to nitrous oxide
• Potentially teratogenic in first trimester
– Avoid hypotension/hypercarbia – fetal
acidosis
Introduction
• NHS maternity statistics 2008-09: UK
c/section rate = 24.6%
• RJMH c/section rate = 36.2%
• NOAD 2007: anaesthesia for c/section
– Spinal – 59.6%
– Epidural top-up – 22.1%
– GA – 10.1%
– CSE – 7.2%
– De novo epidural – 0.8%
RCOA Audit Standards
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Elective c/section > 95% RA
Emergency c/section> 85% RA
Elective c/section <1% RA to GA
Emergency c/section < 3% RA to GA
Elective c/section
• Common indications:
– Maternal request!
– Breech presentation
– Previous c/section
– Placenta praevia
– Significant medical conditions
Choice of Anaesthetic
• Patients preference
• Patients physical profile, health
considerations, pregnancy factors
• Anticipated surgical difficulties
• Experience and speed of surgeon
Preparation for Anaesthesia
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Preop assessment
Informed consent
Antacid prophylaxis
Fully prepared anaesthetic room/theatre
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Checked anaesthetic machine
Monitoring equipment
Tilting operating table
Resuscitation equipment
• Trained anaesthetic assistant
• Large bore I.V. access
Spinal Anaesthesia
• Used >90% elective LSCS
• Incidence of PDPH approx 1:400 due to
small gauge PP needles
• Technically simple
• Consistent, dense quality of block
• Failure rate approx 1%
Spinal Anaesthesia
• Standard technique
– PP needle, no larger than 25G to minimise
PDPH risk
– Injection at, or below L3/L4 interspace to
avoid damage to conus
– Diamorphine 300mcg
– Injection performed in sitting position, then
moved immediately to L tilted supine position
on completion
– Phenylephrine ivi to prevent hypotension
Spinal Anaesthesia
• Hyperbaric Bupivicaine 0.5% - most used
LA in UK
• Recommended doses vary
• Surgery requires sensory blockade to T4
• Patient factors influencing dose
– Height
– Abdominal size
Intrathecal Opiates
• Fentanyl
– Highly lipid soluble
– Reduced intraop discomfort
– Provides no post op analgesia
• Morphine
– Long duration of action
– Little intraop effect due to poor lipophillicity
• Diamorphine
– Rapid onset
– Long duration of action
• Side Effects:
– PONV approx 30%
– Pruritus
Spinal induced hypotension
• Can cause fetal distress
• Symptoms: dizziness, N&V
• Should be treated aggressively
– Approp positioning
– Fluid preloading
– Use of Phenylephrine ivi
• Titrated to maternal BP
• Higher fetal pH than Ephedrine
Spinal after epidural
• Technique most likely to lead to high/total spinal
anaesthesia. ? Dural sac compression by
epidural fluid
• No formula for reducing spinal dose. NB
inadequate block
• Precautions
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Warn patient of risk of conversion to GA
Assess airway
Perform spinal in approp environment
Reduction of spinal dose
Consider leaving epidural catheter in situ
Epidural ‘top-up’
• Category 2 LSCS with epidural in situ
• Slow onset anaesthesia
• Inferior anaesthesia to spinal during
surgery
• L-Bupivicaine 0.5%; Ropivicaine 0.75%;
supplemental Diamorphine.
CSE
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3 approaches
1. ‘Full’ dose spinal with epidural back up if inadequate
block height/duration
2. Reduced dose spinal with supplemental epidural
top-ups
3. Epidural volume extension-low dose spinal extended
by dural sac compression using epidural saline
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‘Needle through needle’
Separate needle, separate interspace
CSE
1. Used to reduce incidence of spinal failure
– Tall patients
– IUGR
– Prolonged surgery
2. Reduces haemodynamic changes by more
gradual onset anaesthesia; reduced risk of
excessive block height
– Cardiac patients
– Short patients
3. Short duration of blockade esp motor blockade
Continuous Spinal
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Niche role
‘Difficult’ equipment
PDPH
Careful titration of dose
Haemodynamic stability
– Cardiac disease
– Extremely small stature
– Severe skeletal deformity
• Extended period of anaesthesia
Pain during LSCS
• Leading cause of litigation
– Closed claims analysis 1995-2007
• Pain during surgery - 31% (57)
• Informed consent
• Give adequate doses of drugs including opioid
• Produce and document adequate sensory and motor
block
• Management
– Alfentanil 250mcg iv
– Entonox
• Conversion to GA
– NB. Clear documentation of management esp if patient refuses
GA
GA
• Indications
– Refusal of RA
– Contraindications eg. Coagulopathy
– Insufficient time to establish RA
– Serious haemorrhage anticipated
– Failed RA
GA
• Reliable and safe if
– Aspiration prophylaxis
– Trained anaesthetic assistance
– Meticulous pre-oxygenation
– Well rehearsed failed intubation drill
– Approp drug regimen to reduce incidence of
awareness
– Awake extubation
Drugs used for GA
• RSI with cricoid pressure
• Thiopentone/Propofol?
– Propofol
• Poorer neonatal profile
• Shorter duration of amnesia
• Longer time to recovery of spontaneous ventilation
• Suxamethonium/Rocuronium?
– Inadequate doses assoc with difficult intubations
• NB 1.5mg/kg; Increased Vd
– Prolonged action of Rocuronium
• NB. Sugammadex
Perioperative Drugs
• Opiates at induction and post op analgesia
• On delivery of neonate
– Syntocinon 5IU and IVI
– Prophylactic antibiotics
• Thromboprophylaxis
Complications
• Failed intubation (1 in 300)
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Increased fatty tissue
Complete dentition
Increased pharnygeal and laryngeal oedema
Incorrect drug dosages
Large tongue
Large breasts
Increasing obesity
Aspiration (1 in 400-600)
Awareness
Increased intaop blood loss
PONV
Post op pain relief
• Introp:
– Diclofenac 100mg PR
– Intrathecal Diamorphine
– IV Morphine and TAP blocks
• Post op:
– Diclofenac 50mg PO TID
– Paracetamol 1g PO QID
– Codeine 30-60mg PO QID
Emergency LSCS
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Grades of urgency – category 1 to 4
Nationally accepted classification
‘Continuum of risk’
Facilitates audit
Improves multidisciplinary communication
Individual, ‘case by case’ approach to
decision to delivery interval
Emergency LSCS
• Category 1 & 2
• In utero fetal resuscitation
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Syntocinon off
Position full L lateral
Oxygen
I.V fluids
Low BP – vasopressors
Tocolysis: GTN 400mcg/B2 agonist
• Choice of anaesthesia
• Post op analgesia
• Post op care