Cricoid pressure

OVERVIEW

• aka Sellick manoeuvre or, most accurately, cricoid force
• the technique was first described in 1961 by Brian Arthur Sellick to prevent aspiration, though Monroe used a similar method in 1774 to prevent gastric insufflation
• cricoid pressure refers to digital pressure against the cricoid cartilage of the larynx, pushing it backwards with the intention of oesophageal compression against the vertebrae and prevention of passive regurgitation of gastric and oesophageal contents
• the cricoid cartilage is the only complete ring-shaped cartilage in respiratory tract, hence it’s potential utility in compressing the esophagus posteriorly
• Cricoid pressure is widely used in English-speaking countries despite a lack of evidence, whereas it is rarely or never used by practitioners in some European countries

INDICATIONS

• proponents advocate use of cricoid pressure to prevent passive regurgitation during rapid sequence intubation (RSI)
• other suggest cricoid pressure is only necessary for high risk cases, e.g. upper GI surgery, obstetric anaesthesia, patients with bowel obstruction

CONTRA-INDICATIONS

• suspected cricotracheal injury
• active vomiting
• unstable cervical spine injuries
• inadequate view of the cords on laryngoscopy
• need for BVM ventilations (rescue ventilations in failed airway)
• decision made to site an LMA instead of performing intubation
• a lack of belief in its utility!

METHOD

• applied by a trained assistant (in theatre this is usually the anaesthetic technician, in the ED it is usually someone who has never seen it done before!)
• identify cricoid cartilage (C6 level, find thyroid cartilage and move inferiorly to find cricothyroid membrane and then feel cricoid caudal to membrane)
• place index finger over cartilage
• then place thumb and middle finger on either side
• apply moderate pressure whilst patient awake with 10N of force
• when patient loses consciousness increase pressure with 30N of force (some authors suggest 40N, others say ‘firm’ pressure, others ‘pressure that would cause pain if applied to the bridge of the nose”)
• keep pressure applied until tracheal intubated, cuff inflated and both lung are being ventilated

RATIONALE

• objective is to achieve oesophageal compression against the vertebrae thus preventing passive regurgitation of gastric and oesophageal contents
• an RCT suggests it limits gastric insufflation during bag-valve-mask ventilation (however, BVM is not typically performed during RSI)
• no aspiration-related deaths in UK obstetric anaesthesia practice since the introduction of cricoid pressure in the late 1960s (though many other improvements in care have occurred, such as positioning, use of antacids, and increased use of spinal anaesthesia)
• no increase in failed intubation rates in elective surgical patients (i.e. <30 seconds using direct laryngoscopy with a MacIntosh blade)

PROBLEMS

• ineffective
  • never been shown to reduce the risk of aspiration
  • some observational studies (see Venner, 2009) have found higher rates of aspiration when cricoid pressure is not used (likely confounders, e.g. higher risk cases more likely to get cricoid pressure)
• often poorly performed, and the assistant may get tired over time
• manoeuvre never validated
  • what is the correct force to apply? (20 to 44N and other subjective descriptions suggested)
• esophagus is lateral to the cricoid cartilage 90% of the time
  • however Rice et al argue that this is irrelevant and that it is the hypopharynx — which is in fixed position relative to the cricoid — that is compressed
• obscures laryngoscopic view potentially making intubation more difficult
  • 2/3 of the time displaces the larynx laterally
  • Zeidan et al 2014 found that cricoid pressure did not alter glidescope view, and they used failure to pass a gastric tube as evidence of upper esophageal occlusion (whether this is a valid test of esophageal occlusion preventing regurgitation is questionable, perhaps it simply makes gastric tube passage more difficult)
• if the patient vomits there is the risk of oesophageal rupture
  • cricoid pressure must be immediately released
• makes bag-mask ventilation and LMA ventilation more difficult
  • compresses the airway 80% of the time
• excessive force may cause airway obstruction
  • 11% of patients have complete airway occlusion
• may block tube passage into the trachea
  • compresses the airway 80% of the time
• cricoid pressure decreases lower esophageal sphincter tone
  • Tournadre et al found that cricoid pressure decreased LES pressure from 24 +/‐ 3 mmHg to 15 +/‐ 4 mmHg at a force of 20N (P < 0.05) and to 12 +/‐ 4 mmHg with a force of 40N (P < 0.01))
  • some argue that this is irrelevant as cricoid pressure is designed to occlude the upper not lower esophagus, however if cricoid pressure is released due to a difficult laryngoscopic view there may be a higher risk of aspiration
• aspiration despite cricoid pressure is well documented in anesthestic and EM literature
• can be uncomfortable for patient if applied before the patient is adequately sedated, and may trigger coughing or vomiting
• adds complexity, increases cognitive load on the intubator and may lead to distraction from other priorities
  • requires an additional assistant
  • may interfere with bimanual laryngoscopy
  • requires additional commands from the intubator (when to apply, when to release)

CONCLUSION

Cricoid pressure should not be a standard part of airway management during intubation (for instance it is not routinely recommended in the NSW HEMS prehospital RSI manual)

This is an example of an intervention introduced with little evidence, handed down from teacher to student over the years as a pseudoaxiom. Pseudoaxioms need to be criticised, studied and discarded where appropriate.

• Some argue that the “best practice compromise for now is to train CP appropriately using recommended guidelines and technique, apply it for RSI as standard and remove it as needed”, however this is likely to be more dangerous as it will lead to distortion of the airway initially, delaying first pass intubation and the cricoid pressure will decrease lower esophageal pressure increasing the risk of regurgitation on release.
• If used, cricoid pressure must be released if there is vomiting, if there is difficulty visualising the cords, if BVM ventilations are required or if an LMA is to be placed
• Make up your own mind! (and adhere to your local departmental guidelines)

References and links

Journal articles and textbooks

• Allman KG. The effect of cricoid pressure application on airway patency. J Clin Anesth. 1995 May;7(3):197-9. PMID: 7669308.
• Bhatia N, Bhagat H, Sen I. Cricoid pressure: Where do we stand? J Anaesthesiol Clin Pharmacol. 2014 Jan;30(1):3-6. PMC3927288.
• Bouvet L, Albert ML, Augris C, Boselli E, Ecochard R, Rabilloud M, Chassard D, Allaouchiche B. Real-time detection of gastric insufflation related to facemask pressure-controlled ventilation using ultrasonography of the antrum and epigastric auscultation in nonparalyzed patients: a prospective, randomized, double-blind study. Anesthesiology. 2014 Feb;120(2):326-34. PMID: 24317204.
• Butler J, Sen A. Best evidence topic report. Cricoid pressure in emergency rapid sequence induction. Emerg Med J. 2005 Nov;22(11):815-6. PMC1726598.
• Ellis DY, Harris T, Zideman D. Cricoid pressure in emergency department rapid sequence tracheal intubations: a risk-benefit analysis. Ann Emerg Med. 2007 Dec;50(6):653-65. PMID: 17681642.
• Harris T, Ellis DY, Foster L, Lockey D. Cricoid pressure and laryngeal manipulation in 402 pre-hospital emergency anaesthetics: essential safety measure or a hindrance to rapid safe intubation? Resuscitation. 2010 Jul;81(7):810-6. PMID: 20398995.
• Landsman I. Cricoid pressure: indications and complications. Paediatr Anaesth. 2004 Jan;14(1):43-7. PMID: 14717873.
• MacG Palmer JH, Ball DR. The effect of cricoid pressure on the cricoid cartilage and vocal cords: an endoscopic study in anaesthetised patients. Anaesthesia. 2000 Mar;55(3):263-8. PMID: 10671846.
• Neilipovitz DT, Crosby ET. No evidence for decreased incidence of aspiration after rapid sequence induction. Can J Anaesth. 2007 Sep;54(9):748-64. PMID: 17766743.
• Ovassapian A, Salem MR. Sellick’s maneuver: to do or not do. Anesth Analg. 2009 Nov;109(5):1360-2. PMID: 19843769.
• Priebe HJ. Use of cricoid pressure during rapid sequence induction: Facts and fiction. Trends Anaes Crit Care. 2 (2012) 123-127
• Rice MJ, Mancuso AA, Gibbs C, Morey TE, Gravenstein N, Deitte LA. Cricoid pressure results in compression of the postcricoid hypopharynx: the esophageal position is irrelevant. Anesth Analg. 2009 Nov;109(5):1546-52. PubMed PMID: 19843793. [Fulltext]
• Sellick BA. Cricoid pressure to control regurgitation of stomach contents during induction of anaesthesia. Lancet. 1961 Aug 19;2(7199):404-6. PMID: 13749923.
• Smith KJ, Dobranowski J, Yip G, Dauphin A, Choi PT. Cricoid pressure displaces the esophagus: an observational study using magnetic resonance imaging. Anesthesiology. 2003 Jul;99(1):60-4. PMID: 12826843.
• Tournadre JP, Chassard D, Berrada KR, Boulétreau P. Cricoid cartilage pressure decreases lower esophageal sphincter tone. Anesthesiology. 1997 Jan;86(1):7-9. PMID: 9009934. [Fulltext]
• Vanner R. Cricoid pressure. Int J Obstet Anesth. 2009 Apr;18(2):103-5. doi: 10.1016/j.ijoa.2009.01.002. PMID: 19233640.
• Zeidan AM, Salem MR, Mazoit JX, Abdullah MA, Ghattas T, Crystal GJ. The effectiveness of cricoid pressure for occluding the esophageal entrance in anesthetized and paralyzed patients: an experimental and observational glidescope study. Anesth Analg. 2014 Mar;118(3):580-6. 24557105.

FOAM and web resources

• University of Wisconsin Video — The Imaging of Cricoid Pressure: Changing our Thinking about a Long-Standing Maneuver
• PHARM — Cricoid Pressure – You Decide
• RAGE — Cricoid: To press or not to press?
• Brian Arthur Sellick (1918 – 1996)