Dr David M Levy

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General anaesthesiafor Caesarean
sectioncurrent controversies

• Dr David M Levy
• Consultant Obstetric Anaesthetist

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General anaesthesiafor Caesarean
sectioncurrent controversies

• Dr David M Levy
• Consultant Obstetric Anaesthetist
• Acknowledgement honoraria from

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Aberdeen Royal Infirmary 1987
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Glen Muick, 1987
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2008 Cape Town
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Notts County English League 2
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GA for CS agenda

• Thiopental, succinylcholine, tube
• ? Necessity for light anaesthesia
• Neonatal outcome
• Uterine tone
• Maternal mortality
• Past present
• Deviation is acceptable
• Cricoid force
• Alternative i.v. agents
• Inhalation induction
• Rocuronium at induction
• Sugammadex

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CS GA rates

• National Obstetric Anaesthesia Database (2005)
• 415728 deliveries
• 97473 CS
• 10727 GA (11.0)
• One third of women have regional block

CS
GA
Rahman K, Jenkins JG Anaesthesia 2005 60 168
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Trainees experience
Searle RD, Lyons G IJOA 2008 17 233
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Training high-fidelity simulation
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Thio, sux, tube50 yrs ago
Hamer Hodges et alBJA 1959

• Group 1 - thio, sux, N2O/O2
• Group 2 - as Group 1 trichloroethylene
• Group 3 - thio, cyclopropane
• Group 4 - N2O/O2/ether ? thio

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?Rapid-sequence induction

• Succinylcholine?
• Maternal respiratory effort inferred baby would
  breathe

Unrelieved aortocaval compression
No cricoid force
Bag mask ventilation
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Deaths from anaesthesia
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Donald Bruce Scott 1925-1998

• If we had been honest, the attraction of the
  new method was the speed and ease with which we
  could present the intubated paralysed patient to
  the obstetrician. We did not advertise the
  increased incidence of death due to Mendelsons
  syndrome and failed intubation which resulted
  from suxamethonium and crash induction.

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GA mortality nadir 94-96
2 cases of anaphylaxis2 airway crises
No GA deaths
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6 direct anaesthesia deaths

• AIRWAY
• oesophageal intubation
• ASPIRATION
• ANAPHYLAXIS
• succinylcholine
• Lessons

Capnography
Competency
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Anaesthesia deaths 03-05

• Ectopic pregnancy
• Obesity, asthma
• Early pregnancy
• Opioid overdose
• CS, asthma, spinal
• Postop. resp. distress
• I.v. bupivacaine
• Haemothorax
• Sublavian cannulation
• Postpartum sepsis
• Renal abscess

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What matters and doesnt matterto the neonate

• Aortocaval compression must be avoided
• Maternal hypoxaemiamust be avoided
• Normocapnia for pregnancymust be maintained
• Uterine incision-delivery interval should be
  minimised
• Paediatrician to support neonatal ventilation

• All anaesthetics/opioids cross the placenta
• Dose andinduction-delivery intervalinfluence
  amount transferred
• Neonatal effect is innocuousandreversible

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Halothane DD Moir BJA 1970
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Halothane DD Moir BJA 1970

• Halothane group
• ?Apgar scores
• No recall
• Previously, 4.5 awareness rate
• No ? blood loss

• N2O/O2 7030compared withN2O/O2 5050
  halothane 0.5

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AwarenessAustralasian surveyJune 05-Jan 07n
1095

• 2 awareness
• (0.26 , CI 0.03-0.9) 1382
• BIS or Entropy used in 32
• n 763 patients had postoperative interviews
• 3 assessors
• Case 1 medication error - thiopentone
• Case 2 remifentanil isoflurane maintenance
• MAC at delivery (mean SD) 1.15 0.5(95 CI
  1.101.20)

Paech MJ et al IJOA 2008 17 298
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Bispectral index (BIS)

• Expert system
• best bits of EEG
• database of 2000USA GAs
• 0 100 (fully awake)
• 60 is threshold to prevent awareness
• What end-tidal vapour concn for BIS lt60 at CS?

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Median Esevo in 50 N2Ofor BISlt60
Chin KJ, Yeo SW Anaesthesia 2004 59 1064-8
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Airway managementAustralasian survey, June
05-Jan 07, n 1095

• Failed intubation 0.4 difficult 3.3 comparable
  with previous studies

Paech MJ et al IJOA 2008 17 292
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Airway management
LMA Supreme?
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Cricoid force questionable efficacy
Smith KJ et al Anesthesiology 2003 99 60-4
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Cricoid force questionable safety

• Distortion of airway anatomy
• Impediment to
• Laryngoscopy
• Tracheal intubation
• Supraglottic airways
• Laryngeal trauma
• Oesophageal rupture
• ? Lower oesophageal sphincter tone
• Regurgitation

• Failure of technique
• ? Failure to
• Intubate
• Ventilate

Priebe H-J Seminars in Anesthesia, Perioperative
Medicine and Pain2005 24 120-6
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Cricoid force view at laryngoscopy

• a force close to 30N may cause complete loss of
  the glottic view

Haslam, Parker, Duggan Anaesthesia 2005 60 41-47
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Cricoid yoke view through LMA

• Force-dependent cricoid deformation
• Complete occlusion airway obstruction at 44N in
  ?50
• ? at greater risk

Palmer BallAnaesthesia 2000 55 260-8
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Cricoid force performance

• British Association of Operating Department
  Assistants
• n135
• Performance improves with practical training

Meek, Gittins, Duggan Anaesthesia 1999 54 59-62
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Inhalation induction?

• Halothane concern about effect of residual
  vapour on uterine toneafter delivery

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Inhalation induction?

• Sevoflurane
• no i.v. access
• needle phobia
• status asthmaticus
• Not necessarily unsafe
• head-up
• avoid cricoid force
• prime breathing system with 8 in N2O/O2
• tidal respiration

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EXIT (ex-utero, intrapartum technique/tracheopla
sty)

• 2 MAC (end-tidal) vapour for uterine relaxation

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Uterine contractility
Turner et al. IJOA 2002 11 246

• Effect of insoluble vapours is readily reversible
• Syntocinon infusion

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All induction agents are OK
2.5 mg.kg-1
0.3 mg.kg-1
0.3 mg.kg-1
5-7 mg.kg-1
2 mg.kg-1
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TIVA remifentanil propofol

• Remifentanil
• Bolus 0.5 µg kg-1
• Infusion 0.2 µg kg-1 min -1
• Propofol TCI
• 45 s after remifentanil bolus5 µg ml-1
• After tracheal intubation2.5 µg ml-1

Van de Velde et al IJOA 2004 13 153
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Pre-eclampsia/eclampsia...must protect the
cerebral circulation

• Neuroanaesthetic
• obtund pressor response
• Remifentanil 2 µg kg-1orAlfentanil 10 µg kg-1
• Provision for neonatal ventilatory support

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Blood pressure was 200/105 mm/Hg in the
anaesthetic room prior to (standard) induction of
anaesthesia. Intubation proved difficult and
systolic pressure was 195-210 mmHg for the first
15 minutes of the operation. Baby was delivered
in reasonable condition but the mother could not
be roused from general anaesthesia. A delayed CT
scan showed massive intracranial haemorrhage.
Hepatic haemorrhage was also seen at autopsy.
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Blood pressure was 200/105 mm/Hg in the
anaesthetic room prior to (standard) induction of
anaesthesia. Intubation proved difficult and
systolic pressure was 195-210 mmHg for the first
15 minutes of the operation. Baby was delivered
in reasonable condition but the mother could not
be roused from general anaesthesia. A delayed CT
scan showed massive intracranial haemorrhage.
Hepatic haemorrhage was also seen at autopsy.
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Sux vs rocuronium for CS

• Succinylcholine
• Wait for fasciculations
• Hope it works
• Go for it!
• Limited time to succeed
• Implement failed intubation drill
• Potentially dangerous recovery phase

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Recovery from succinylcholine

• Succinylcholine can turn cant intubate can
  ventilate into cant intubate cant ventilate

Naguib et al Anesthesiology 2005 102 35
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Sux vs rocuronium for CS

• Succinylcholine
• Wait for fasciculations
• Hope it works
• Go for it!
• Limited time to succeed
• Implement failed intubation drill
• Potentially dangerous recovery phase

• Rocuronium
• 0.6 mg kg-1
• licensed for CS
• Wait gt45 seconds
• head-up
• Efficacy not in doubt
• Committed to IPPV
• until Nov 2008

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Sugammadex (Bridion)
Prof Rajinder Mirakhur
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Reversal of NMB mechanisms
ACh, acetylcholine.AChE, acetylcholinesterase.Ch
E, cholinesterase.nAChR, nicotinic acetylcholine
receptor.NMBA, neuromuscular blocking agent.
Adam JM et al. J Med Chem. 2002451806-1816.
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Reversal of NMB mechanisms
ACh, acetylcholine.AChE, acetylcholinesterase.Ch
E, cholinesterase.nAChR, nicotinic acetylcholine
receptor.NMBA, neuromuscular blocking agent.
Adam JM et al. J Med Chem. 2002451806-1816.
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Reversal of NMB mechanisms
ACh, acetylcholine.AChE, acetylcholinesterase.Ch
E, cholinesterase.nAChR, nicotinic acetylcholine
receptor.NMBA, neuromuscular blocking agent.
Adam JM et al. J Med Chem. 2002451806-1816.
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The doughnut and the holea new pharmacological
concept for anaesthetists
Editorial BJA 2006 97 123
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Cyclodextrins

• Cyclic oligosaccharides, defined by the number of
  glucopyranoside units
• 6 units - a7 units - ß8 units - ?
• Structure
• Lipophilic cavity
• Hydrophilic exterior
• Can form water-soluble inclusion complexes

a-CD
ß-CD
?-CD
CD cyclodextrin
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Encapsulation of Rocuronium
Cameron KS et al. Org Lett. 200243403-3406.
Gijsenbergh F et al. Anesthesiology.
2005103695-703.
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Sugammadex

• Anaesthetists have hitherto lacked control over
  neuromuscular blockade
• In contrast to i.v. agent/vapour delivery
• Remifentanil, desflurane etc
• Sugammadex can reverse shallow or profound
  blockade
• Completely
• Speed dose-dependent
• Sugammadex is unrelated to anticholinesterases
• No unwanted muscarinic cholinergic/
  anticholinergic effects

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Rocuronium/Sugammadex

• ROCURONIUM0.6 mg kg-1 after thiopental 6 mg
  kg-1 ? intubation at 90 s
• Lasts around 30 min
• 1.2 mg kg-1 hasnt been studied in obstetrics

• SUGAMMADEX
• 3 min afterrocuronium 1.2 mg kg-1
• 16 mg kg-1 ?TOF 0.7 in 60 s
• Placental transfer 2-6
• Rat rabbit
• Further roc (or vec) wont work for 24 hr

Pühringer et al Anesthesiology 2008 109 188
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Roc ? Sugammadex vs placebo
TOF-Watch SX traces of the first twitch height
and T4/T1 ratio.(A) treated with rocuronium 1.2
mg kg-1 and placebo
Molina A. L. et al. Br. J. Anaesth. 2007
98624-627
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Roc ? Sugammadex vs placebo
TOF-Watch SX traces of the first twitch height
and T4/T1 ratio.(A) treated with rocuronium 1.2
mg kg-1 and placebo(B) treated with rocuronium
1.2 mg kg-1 and sugammadex 40 mg kg-1
Molina A. L. et al. Br. J. Anaesth. 2007
98624-627
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Roc/Sugammadex vs Sux
Naguib M Anesth Analg 2007104 575
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Sugammadex

• Sugammadex (Bridion)
• 100 mg ml-1 ampoules
• 2 ml (59.64)
• 5 ml (149.10)
• Shelf life 3 yrs
• Store lt30?C

• 16 mg kg-1 for80 kg woman
• 1280 mg
• 417.48

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Original Failed Intubation Drill 1976

• Succinylcholine recovery
• Spontaneous respn
• Oxygenation difficult
• Wake up
• Regional technique
• 2008indications for GA
• Category 1 urgency
• Failed regional block

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Oxygenation without aspiration

• Plan - dont panic

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Take-home messages

• No justification for light anaesthesia
• Anaesthetics dont harm the fetus
• No excuse for awareness
• Sugammadex
• No evidence in obstetrics
• Potential for
• Increasing rocuronium intubating dose (and ?speed
  of onset)
• Rapid reversal of profound rocuronium blockade

General anaesthesia for Caesarean section
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Questions...
dmlevy_at_nhs.net
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ARI ICU Christmas Day 1988