Cricoid pressure: does it actually work?

The trial everyone cites is misreported in both directions — and the anatomy the technique depends on turns out to be the exception rather than the rule.

Reviewed and updated August 2026 · Written by Anastasia Jackson, DNAP, CRNA

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This is one of the few questions where the evidence gets misreported in both directions. The trial everyone cites did not show that cricoid pressure works, and it did not show that it doesn’t — and understanding why is more useful than either headline.

What IRIS actually found

A randomized, double-blind, non-inferiority trial across 10 French academic centers, enrolling 3,472 patients undergoing rapid sequence induction between February 2014 and February 2017. Blinding was achieved with an opaque cover over the assistant’s hand: cricoid pressure at 30 N with three fingers, or a sham with no pressure applied.^1,2

The risk difference for aspiration was −0.06% (95% CI −0.57 to 0.42), and the same result held in the per-protocol population, in patients without a nasogastric tube, and in those requiring emergency surgery.¹

Why “failed to demonstrate non-inferiority” is not “cricoid works”

That cuts both ways. Anyone citing IRIS as proof that cricoid pressure is useless is over-reading it. Anyone citing the failed non-inferiority as evidence that cricoid pressure should be retained is over-reading it in the other direction.

The anatomy problem

The maneuver assumes the esophagus sits directly behind the cricoid ring, so that posterior pressure compresses it against the vertebral body. Ultrasound imaging in 110 volunteers found otherwise:⁴

In other words, the midline anatomy the technique depends on is the exception rather than the rule. This has driven interest in alternatives — left paratracheal pressure has been tested against cricoid pressure and found non-inferior for intubation time, with significantly less difficulty advancing the tube.⁵

What the wider evidence says

A systematic review and meta-analysis of randomized trials concluded that cricoid pressure failed to show any increase in protection from aspiration and may increase the difficulty of intubation, with further studies needed in high-risk populations such as intensive care patients.⁶

Historical context is worth knowing: the maneuver was described by Sellick in 1961, though similar techniques appear in the literature as far back as the 1770s, and the initial studies supporting it had small numbers, no blinding, no randomization and selection bias.² It became a standard of care largely on physiological reasoning rather than on outcome data.

The technique argument

One defense of cricoid pressure is that it fails because it is applied badly rather than because it does not work. There is something in this — a meta-analysis of eight studies found that intubation success rates improved after cricoid pressure training.⁷ But IRIS specifically trained its operators repeatedly with the aim of eliminating poor technique,³ and still produced the secondary endpoints above. Force is also notoriously inconsistent in practice, which is why devices to measure applied pressure in real time are under development.⁸

The practical reading

• The evidence does not support cricoid pressure as protective, and it does show a consistent cost in laryngoscopic view, intubation time and trauma.
• The evidence also does not exclude a small protective effect, because the outcome is too rare to have been measured properly.
• If it is used, release it early when the view is poor — IRIS found the maneuver was interrupted nearly three times as often in the cricoid group, which suggests operators were already doing this.
• Do not let it delay or degrade intubation. The measured harms are all in that direction.
• Populations remain unstudied — the authors specifically called for further studies in pregnant women and outside the operating room.¹

Frequently asked questions

Did the IRIS trial disprove cricoid pressure?

No, and it is routinely misreported. IRIS was a non-inferiority trial testing whether a sham was non-inferior to cricoid pressure, and it failed to demonstrate non-inferiority.¹ But the aspiration rates were nearly identical (0.6% versus 0.5%), and the trial was powered on an assumed rate of 2.8% — roughly five times what was observed — leaving it underpowered for its own primary question.³

Does cricoid pressure make intubation harder?

The data say yes. In IRIS, Cormack–Lehane grade 3–4 views occurred in 10% of the cricoid group versus 5% of the sham group, intubation took longer than 30 seconds in 47% versus 40%, and traumatic complications occurred in 3% versus 1% — all p < 0.001.¹ A meta-analysis reached the same conclusion.⁶

Where is the esophagus relative to the cricoid cartilage?

Usually not directly behind it. Ultrasound of 110 volunteers found the esophagus partially to the left in 78.18%, completely to the left in 4.54%, to the right in 1.81%, and not visualizable in 15.45%.⁴ The midline anatomy the maneuver depends on is the exception.

Is cricoid pressure still recommended?

Practice has already diverged. An international survey of 491 practitioners across 61 countries found the Sellick maneuver in use by 42% of respondents,⁹ and there is no international guideline consensus on rapid sequence induction technique. Institutional protocol varies, and this is a reasonable place to follow yours while knowing what the evidence does and does not show.

Is there an alternative to cricoid pressure?

Left paratracheal pressure has been tested directly against cricoid pressure and found non-inferior for intubation time, with a significantly lower tube advancement difficulty score.⁵ It targets the esophagus where imaging actually finds it rather than where the classical technique assumes it to be.

References

1. Birenbaum A, Hajage D, Roche S, et al; IRIS Investigators Group. Effect of cricoid pressure compared with a sham procedure in the rapid sequence induction of anesthesia: the IRIS randomized clinical trial. JAMA Surg. 2019;154(1):9–17. doi:10.1001/jamasurg.2018.3577. PMID 30347104. ClinicalTrials.gov NCT02080754.
2. Cricoid pressure in airway management: the IRIS trial. REBEL EM. Covers the trial design, the sham technique, and the historical origin of the maneuver including the pre-Sellick descriptions and the methodological flaws of the initial studies.
3. JC: cricoid pressure and RSI, do we still need it? St Emlyn’s. Sets out the power calculation problem — recruitment targets based on an estimated 2.8% aspiration prevalence against a far lower observed rate — and the operator training protocol.
4. Bermede O, Meço BC, Baytaş V, et al. What about compressing the oesophagus with an ultrasound probe for a modified Sellick maneuver? Turk J Anaesthesiol Reanim. 2022. doi:10.5152/TJAR.2021.1427. One hundred ten volunteers; esophageal position relative to the cricoid ring.
5. Kim HY, Moon JH, Park HY, Min SK, Kim JY. A noninferiority trial comparing left paratracheal pressure versus cricoid pressure on tracheal intubation conditions using the Pentax Airway Scope. Sci Rep. 2022;12:16299. doi:10.1038/s41598-022-20681-y
6. Cricoid pressure during intubation: a systematic review and meta-analysis of randomised controlled trials. Heart Lung. 2019. doi:10.1016/j.hrtlng.2019.10.001
7. Systematic review and meta-analysis of cricoid pressure training and education efficacy. PMID 29851051. Eight eligible studies.
8. Validation of a novel handheld device for accurate cricoid pressure in healthy volunteers. ClinicalTrials.gov NCT06540625. University Health Network, Toronto. Describes the force inconsistency problem motivating device development.
9. International declarative survey of rapid sequence induction practice across the ESAIC network. 491 respondents in 61 countries; Sellick maneuver used by 42%.