Written by Clay Smith
The evidence does not support routine use of cricoid pressure (CP) to prevent pulmonary aspiration during intubation.
Why does this matter?
Sellick proposed CP in a case series of 26 patients considered at risk for aspiration but had no control group. In fact, CP may be biomechanically impossible. There is also little compelling evidence that it is effective. IRIS found that sham vs real cricoid pressure was identical in terms of pulmonary aspiration (0.5% without; 0.6% with) and slightly increased time to intubation. In light of this controversy being reignited, the authors set out to compile the known evidence.
In 2003, an MRI study showed cricoid pressure often laterally displaced the esophagus.
But in 2009, a new study showed that it was the hypopharynx that lies behind the cricoid ring at the C5 level which is fixed, immobile, and consistently compressed by cricoid pressure. Therefore, esophageal position was irrelevant.
Aspiration is bad
Aspiration of gastric contents may be lethal.
The authors argue it should be defined as, “bilious secretions or particulate material in the tracheobronchial tree or a new infiltrate on a chest roentgenogram,” producing clinical effects, such as hypoxia rather than defined as micro-aspiration by pepsin-A measurement.
Airway management effects
It makes supraglottic device placement, videolaryngoscopy (multiple studies), and tube passage harder.
Although, it may make direct laryngoscopy easier.
If done, it should be posterior pressure on the anterior cricoid with two fingers, 30N of force. It may be biomechanically impossible, as laryngoscopy provides direct counterforce.
Most agree it should be performed in pregnant women. Most agree it should not be used in known unstable c-spine fracture.
A 30N left paratracheal force reduced gastric insufflation of air with bag-valve mask.
CP is much more common in the U.S., likely due to malpractice fears based on closed claims’ analysis.
There is little solid evidence for using CP. The RCT we have indicates it does not reduce aspiration.
“Using the best currently available techniques, the incidence of pulmonary aspiration is not zero. This fact should be universal knowledge and should be well explained in medico-legal situations.”
In my practice, I have largely abandoned use of CP. It doesn’t reduce aspiration and makes a difficult airway even more difficult. Why would I want to do that?
The Clinical Use of Cricoid Pressure: First, Do No Harm. Anesth Analg. 2019 Aug 6. doi: 10.1213/ANE.0000000000004360. [Epub ahead of print]
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Reviewed by Thomas Davis