Dr David M Levy

1
Myth or evidence-based practice?Cricoid force is
essentialto prevent aspiration

• Dr David M Levy
• Consultant Obstetric Anaesthetist

2
Cricoid Pressure (CP)

• Sellicks 1961 case series
• Modern imaging
• MR
• Endoscopy
• Tracheal intubation
• Supraglottic airways
• Application of CP
• End-point aspiration
• Regurgitation

3
The Lancet, 1961

• BA Sellick, 1918-1996

• ME Tunstall, 1928-

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The Lancet, 1961

• Two notable preliminary communications
• Cricoid pressure to control regurgitation of
  stomach contents during induction of anaesthesia
• BA Sellick, August 19
• The use of a fixed nitrous oxide and oxygen
  mixturefrom one cylinder
• ME Tunstall, 28 October

5
The Lancet, 1961

• Two notable preliminary communications
• Cricoid pressure to control regurgitation of
  stomach contents during induction of anaesthesia
• BA Sellick, August 19
• The use of a fixed nitrous oxide and oxygen
  mixturefrom one cylinder
• ME Tunstall, 28 October

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Sellicks case series (1961)

• No randomisation
• Position head-down
• Head neck fully extended
• ? Induction drug regimen

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Sellicks case series (1961)
Sellick BA Lancet 1961 2 404-6
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Sellicks case series (1961)
Sellick BA Lancet 1961 2 404-6
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Sellicks case series

• ? Force applied
• ? Effect on laryngoscopy/intubation
• ? ? Gastric distension with IPPV
• pure speculation

Priebe H-J Seminars in Anesthesia, Perioperative
Medicine and Pain2005 24 120-6
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CP the downside (primum non nocere)

• 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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40 years on from Sellick - MR imaging
Smith KJ et al Anesthesiology 2003 99 60-4
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CP 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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CP failed intubation
Turgeon AF et al Anesthesiology 2005 102 315-9
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CP failed intubation

• Failure rate at 30s, Macintosh 3 blade
• Mean BMI 25, all lt35
• Mostly Mallampati 1 2
• Trained assistants
• 30 N, daily simulation
• Lateral shift of larynx
• 43 CP, 9 sham plt0.0001
• Failure to intubate
• 15 CP, 13 sham NS

Turgeon AF et al Anesthesiology 2005 102 315-9
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CP application

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

Meek, Gittins, Duggan Anaesthesia 1999 54 59-62
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CP regurgitation in high-risk patients

• Methylene blue capsule pre-induction
• Oehlkern L, Anesthesiology 2003 A1235

No CP n65 CP n65 P
Induction 3 0 0.05
Extubation 7 6 0.7
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Aspiration Australian Incident Monitoring Study

• Anonymous self-reporting
• First 5000 incidents
• 133 cases of aspiration
• Majority in elective cases
• Mostly at induction
• Commonest with facemask or LMA
• CP applied in 11 (8)

Kluger MT, Short TG Anaesthesia 1999 54 19-26
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CP ? incidence of aspiration?

• Neilipovitz DT, Crosby ET (2007)
• No evidence for decreased incidence of aspiration
  after rapid sequence induction
• Cricoid pressure
• Level 5 evidence (Expert opinion)
• Grade D recommendation
• troublingly inconsistent or inconclusive
  studies

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CP in the ED risk-benefit analysis

• We recommend that the removal of CP be an
  immediate consideration if there is any
  difficulty intubating or ventilating the ED
  patient

Ellis DY et al Ann Emerg Med 2007 50 653-65
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CP supraglottic airways 1

• Proseal LMA
• n 50
• Cricoid pressureimpedes
• Placement
• Ventilation

Li et alAnesth Analg 2007104 1195-8
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LMA Supreme?
Verghese C, Ramaswamy B BJA 2008 101 404-10
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CP supraglottic airways 2

• Laryngeal tube(-suction II)
• n 40
• Cricoid pressureimpedes
• Placement
• Ventilation

Asai et alBJA 200799 282-5
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Emergency abdominal surgery

• Fabregat-López et al
• Proseal LMA
• No cricoid pressure
• No complications
• Controversial
• Editorial Pandit

2008 63 967
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CP current opinion

• Koerber et alVariation in RSI techniques
• current practice in Wales
• 5 scenarios who would intubate trachea without
  CP
• Appendicectomy 5
• Symptomatic hiatus hernia 11
• Asymptomatic hiatus hernia 12
• Elective C Section 2
• Bowel obstruction 1

2009 64 54
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Conclusion

• Cricoid pressure in RSI - whats the evidence
  base?

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Conclusion

• Cricoid pressure in RSI - whats the evidence
  base?
• Must weigh efficacy in preventing aspiration
  against risk of impeding tracheal
  intubation/ventilation Turgeon et al 2005
• By todays standards, cricoid pressure can
  hardly be considered an evidence-based practice.
  Priebe 2005

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A personal view

• 30 head-up position
• Precalculated doses
• Induction agent
• Rocuronium
• Forget CP
• Little faith in correct application
• Dont provoke emesis
• Priority Optimal conditions for
  successfulairway management

May the (cricoid) force be with you?
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Questions...
dmlevy_at_nhs.net