Medical Myths: Cricoid Pressure
Minh Le Cong MD and Anand Swaminathan MD
Cricoid pressure was first described by Dr. Sellick in the 1960s. It refers to applying pressure over the cricoid cartilage, generally with two fingers, such as the thumb/index finger or thumb/middle finger. This provides direct posterior pressure backward onto the cricoid cartilage. The premise is to push the cricoid cartilage against the esophagus to occlude it and prevent regurgitation of stomach contents into the upper airway. The initial papers were small, non-randomized case series with the author as the main researcher.
Le Cong. There are some studies that show that it can cause airway obstruction and does not reduce regurgitation. However, we haven’t been taught to do it properly or safely. If you do cricoid pressure on yourself, you will find that you will be unable to swallow at some point. It is a simple maneuver and you can remove it at any time. The data is not robust but there are some randomized controlled trials currently underway in Australia looking at this issue.
Swaminathan.
- There are a number of studies using MRI that show that in most people, the esophagus actually lies lateral to the cricoid cartilage. When cricoid pressure was applied under MRI, these studies found that the esophagus tends to be displaced laterally if it wasn’t already displaced. There is one study that refutes this. A study by Rice in 2009 found that cricoid pressure resulted in reduction of the diameter of the hypopharynx by 35%, and that the hypopharynx and cricoid ring moved together as a unit. This compression, and not displacement, of the esophagus was felt to decrease the risk of aspiration.
- Rice MJ, et al. Cricoid pressure results in compression of the postcricoid hypopharynx: the esophageal position is irrelevant. Anesth Analg. 2009 Nov;109(5):1546-52. [PMID: 19843793]
- A study by Jim Tsung found that visualization with ultrasound shows that the esophagus is lateral to the airway in 60 percent of patients. Cricoid pressure led to displacement in all.
Tsung JW, et al. Dynamic anatomic relationship of the esophagus and trachea on sonography: implications for endotracheal tube confirmation in children. J Ultrasound Med. 2012 Sep;31(9):1356-70. [Open access link]
- Cricoid pressure does not do what we have been told it does. Also, it probably decreases the tone in the lower esophageal sphincter, which may increase regurgitation.
- Cricoid pressure decreases airway patency. There are multiple papers that show that cricoid pressure in intubated patients results in increased peak pressures. It may be more difficult to bag these patients.
- Cricoid pressure obscures your view of the airway. Cricoid pressure can cause the vocal cords to close.
- Oh J, et al. Videographic analysis of glottic view with increasing cricoid pressure force. Ann Emerg Med. 2013 Apr;61(4):407-13. [PMID: 23306455] This study showed that cricoid pressure worsened the glottic view.
- There is no study that shows cricoid pressure reduces aspiration. An observational, retrospective chart review done in Africa looked at 4,891 patients who underwent C-sections. Cricoid pressure was applied in 61% of patients, and 24 vomited during induction. There were 11 deaths that were attributed to aspiration, and 9 of these were in the group with cricoid pressure. However, this is not a randomized controlled trial.
- Fenton PM, et al. Life-saving or ineffective? An observational study of the use of cricoid pressure and maternal outcome in an African setting. Int J Obstet Anesth. 2009 Apr;18(2):106-10. [PMID: 19144507]
- In summary, cricoid pressure doesn’t do what it is supposed to. It pushes the esophagus laterally. It relaxes the lower esophageal sphincter, which may make patients more likely to experience passive regurgitation. It makes ventilation and views of the airway more difficult. In 50 years, there is not a single, well-done, randomized, controlled trial showing benefit.
Le Cong. Sometimes you don’t need great evidence to say that something is a reasonable idea because of the principle that we are trying to do the best for our patients in minimizing the harm for the procedure. This is similar to manual in-line stabilization for intubation in trauma patients; there is very little evidence supporting it, but it is considered the standard of care.
Nicholas N. - April 15, 2015 12:48 PM
Hi,
Excellent Review. Great to see this topic to resurface. Just wanna give my opinion regarding Minh's points pro Cricoid Pressure. It is true that a lot of medical procedures we are doing are not entirely evidence supported, but in some way these procedures are based on basic sciences and theorectical pathophysiology. Eg given in-line stabilisation for intubation in trauma. But in the case of cricoid pressure, the fundamental of cricoid pressure to occlude the oesophagus has been radiologically proven not effective. I think compressing the esophagus to a point it impairs swallowing does not prove anything about preventing regurgitation which involves separate mechanism.
Being the supporter of non believer of cricoid pressure, i think the fundamental of medicine is still do no harm. The procedure itself is not without risk as mentioned in the podcast, and benefit is based on a debunked idea.
Paul D. - April 17, 2015 7:16 AM
The fact that we don't have good evidence for inline stabilization as a reason for doing cricoid pressure is fallacious.
Patrick T. - May 3, 2015 6:33 AM
i have always thought of cricoid pressure as being used to get a better view in someone with anterior anatomy. i learned it 25 years ago as a medic and still occasionally have a nurse or medic apply it in the ed and multiple times it has helped with visualization of the cords. just my experience.
Anand S. - May 3, 2015 6:56 AM
Patrick - thanks for the comment. It sounds like you're talking about bimanual manipulation of the airway. I think most airway people are in favor of bimanual manipulation. This allows us to move the airway (especially an anterior one) into view. Cricoid is a specific, blind maneuver simply aimed at occluding the esophagus. I hope this clarifies. Keep the comments coming!