This topic was selected because an evidence synthesis beats a textbook on it: the trials disagree, or the guidance has moved recently.
THE EVIDENCE
What each source contributes, and how strong it is
Study design first — a cohort and a randomised trial do not carry the same weight.
Design
Year
Journal
What it found
Meta-analysis
2020
Heart & lung : the journal of crit
Across 12 randomised trials in 4,862 patients, cricoid pressure did not reduce
Cohort
2003
Anesthesiology
The oesophagus already lies lateral to the cricoid in more than half of necks
Cohort
2024
BMC anesthesiology
Rapid Sequence Induction (RSI) was used in 82% of patients undergoing tracheal
Review
2021
Anesthesia and analgesia
Current data are inadequate to mandate either continuing or abandoning cricoid pressure
Randomised trial
1992
British journal of anaesthesia
Applying cricoid pressure significantly decreases the success rate of initial
Review
2025
Anesthesiology
Modern evidence suggests cricoid force does not meaningfully impair successful
6 resolved citations behind this deck; every point above traces to one of them.
WHERE THE GUIDANCE SITS
Across 12 randomised trials in 4,862 patients, cricoid pressure did not reduce
Meta-analysis · Heart & lung : the journal of crit
Across 12 randomised trials in 4,862 patients, cricoid pressure did not reduce aspiration, but it worsened first-attempt success, added nearly 7 seconds to intubation and worsened the laryngoscopic view.
Cricoid Pressure During Intubation: A Systematic Review and Meta-Analysis of Randomised Controlled Trials, Heart & lung : the journal of critical care 2020 · PMID 31685271
THE NUMBERS
Cricoid pressure did not reduce aspiration, and worsened the view
12 randomised trials, 4,862 patients.
No protection against aspiration; worse first-attempt success and a worse laryngoscopic view.
Cricoid Pressure During Intubation: A Systematic Review and Meta-Analysis of Randomised Controlled Trials, Heart & lung : the journal of critical care 2020 · PMID 31685271
WHAT THE TRIALS FOUND
Applying cricoid pressure significantly decreases the success rate of initial
Randomised trial · British journal of anaesthesia
Applying cricoid pressure significantly decreases the success rate of initial laryngeal mask airway insertion, requiring its removal for successful placement.
Cricoid Pressure May Prevent Insertion of the Laryngeal Mask Airway, British journal of anaesthesia 1992 · PMID 1467077
IN PRACTICE
What the cohorts and reviews add
4 findings, each on the slide that follows.
Anesthesiology 2003
The oesophagus already lies lateral to the cricoid in more than half of necks
The oesophagus already lies lateral to the cricoid in more than half of necks
BMC anesthesiology 2024
Rapid Sequence Induction (RSI) was used in 82% of patients undergoing tracheal
Rapid Sequence Induction (RSI) was used in 82% of patients undergoing tracheal intubation in this cohort.
Anesthesia and analgesia 2021
Current data are inadequate to mandate either continuing or abandoning cricoid pressure
Current data are inadequate to mandate either continuing or abandoning cricoid pressure
Anesthesiology 2025
Modern evidence suggests cricoid force does not meaningfully impair successful
Modern evidence suggests cricoid force does not meaningfully impair successful intubation when videolaryngoscopy is used
IN PRACTICE
The oesophagus already lies lateral to the cricoid in more than half of necks
Cohort · Anesthesiology
The oesophagus already lies lateral to the cricoid in more than half of necks, and applying cricoid pressure displaces it further sideways while also compressing the airway in 81%.
Cricoid Pressure Displaces the Esophagus: An Observational Study Using Magnetic Resonance Imaging, Anesthesiology 2003 · PMID 12826843
IN PRACTICE
Rapid Sequence Induction (RSI) was used in 82% of patients undergoing tracheal
Cohort · BMC anesthesiology
Rapid Sequence Induction (RSI) was used in 82% of patients undergoing tracheal intubation in this cohort.
Airway Management and Pulmonary Aspiration During Surgical Interventions in Pregnant Women in the 2nd/3rd Trimester and Immediate Postpartum - A Retrospective Study in a Tertiary Care University Hospital, BMC anesthesiology 2024 · PMID 38702641
IN PRACTICE
Current data are inadequate to mandate either continuing or abandoning cricoid pressure
Review · Anesthesia and analgesia
Current data are inadequate to mandate either continuing or abandoning cricoid pressure, and no universally accepted standard exists for the high-risk aspiration patient.
The Clinical Use of Cricoid Pressure: First, Do No Harm, Anesthesia and analgesia 2021 · PMID 31397697
IN PRACTICE
Modern evidence suggests cricoid force does not meaningfully impair successful
Review · Anesthesiology
Modern evidence suggests cricoid force does not meaningfully impair successful intubation when videolaryngoscopy is used, and where it is applied it may be improved by ultrasound localisation and a trained assistant.
If you reach for a supraglottic airway as rescue, release the cricoid first.
THE NUMBERS
The pressure it generates is real, whatever the outcome data show
High-resolution manometry at the upper oesophageal sphincter, 30 N applied.
Far above the level thought necessary to prevent regurgitation — the mechanism is not the weak link.
INDICATIONS
When this is the right block
IRIS trial, cricoid pressure versus sham, JAMA Surg 2019
Rapid sequence induction in a patient at risk of aspiration
The IRIS trial randomised 3472 patients to cricoid pressure or a sham procedure. Pulmonary aspiration occurred in 10 patients (0.6%) with cricoid pressure and 9 (0.5%) with sham, but the upper limit of the one-sided 95% confidence interval for relative risk was 2.00, exceeding the prespecified 1.50, so noninferiority of omitting it was not demonstrated.
Cricoid pressure and failed intubation RCT, Anesthesiology 2005
Applied by someone trained to apply it
In 700 adults randomised to standardised cricoid pressure or sham during direct laryngoscopy, failed intubation at 30 seconds occurred in 4.4% versus 3.7% (P = 0.70), with comparable Cormack-Lehane grades and Intubation Difficulty Scale scores; median intubation time was 11.3 versus 10.4 seconds.
Effectiveness and risks of cricoid pressure in the ED, Emerg Med Australas 2022
Outside theatre, the evidence thins out further
A systematic review of emergency department rapid sequence induction found only three eligible studies — one randomised trial of 54 patients and two registry studies of 3710 — and concluded there is insufficient evidence to say whether cricoid pressure affects first-pass success or the incidence of complications.
CONTRAINDICATIONS
When it is not
IRIS trial, cricoid pressure versus sham, JAMA Surg 2019
Continuing it when laryngoscopy is difficult
In IRIS, the Sellick group had more Cormack-Lehane grade 3 and 4 views (10% versus 5%) and more intubations taking longer than 30 seconds (47% versus 40%). If the view is poor, releasing the pressure is the intervention.
Cricoid pressure and failed intubation RCT, Anesthesiology 2005
Delegating it to someone who has not been trained in it
The randomised evidence that cricoid pressure does not increase failed intubation is explicitly conditioned on application by trained personnel using a standardised technique. Untrained application is a different intervention from the one that was studied.
Cricoid pressure displaces the esophagus, Anesthesiology 2003
Believing it occludes the oesophagus
On magnetic resonance imaging of 22 volunteers, the oesophagus was already lateral to the cricoid in 52.6% of necks without cricoid pressure and in 90.5% with it, and cricoid pressure produced lateral laryngeal displacement in 66.7% and airway compression in 81.0% of necks.
IRIS trial, cricoid pressure versus sham, JAMA Surg 2019
Extending the trial result to pregnancy or outside the operating room
IRIS enrolled patients undergoing anaesthesia with rapid sequence induction in ten academic centres and its authors state that further studies are required in pregnant women and outside the operating room. Neither population was answered by this trial.
PEARLS
What experience adds
Effectiveness and risks of cricoid pressure in the ED, Emerg Med Australas 2022
Aspiration happened in both arms of every study that looked
The emergency department systematic review found that aspiration occurred regardless of whether cricoid pressure was applied, and that first-pass success was not reduced by it — but the authors are explicit that three studies are not enough to draw firm conclusions either way.
The clinical use of cricoid pressure: first, do no harm, Anesth Analg 2021
The disagreement is between guidelines, not between doctors and evidence
Some rapid sequence induction guidelines recommend cricoid pressure and other international guidelines do not, and the available data are inadequate to impose a clinical guideline in either direction; practice differs between US and international practitioners for that reason.
Name the person and agree the release word
Before induction, say who is applying it, where their fingers go, and the exact word that means let go. A pair of hands on the neck that nobody has briefed is a pair of hands nobody can call off.
IN THE ROOM
What this changes about the next case
Colour is the strength of the evidence behind each step, not the urgency.
1
1
Across 12 randomised trials in 4,862 patients, cricoid pressure did not reduce aspiration, but it worsened first-attempt success, added nearly 7 seconds to intubation and worsened the laryngoscopic view.
2
2
Applying cricoid pressure significantly decreases the success rate of initial laryngeal mask airway insertion, requiring its removal for successful placement.
3
3
The oesophagus already lies lateral to the cricoid in more than half of necks, and applying cricoid pressure displaces it further sideways while also compressing the airway in 81%.
4
4
Rapid Sequence Induction (RSI) was used in 82% of patients undergoing tracheal intubation in this cohort.
5
5
Current data are inadequate to mandate either continuing or abandoning cricoid pressure, and no universally accepted standard exists for the high-risk aspiration patient.
The oral-boards stem on the next slide puts these into one scenario.
KEY TAKEAWAYS
What to carry into the next case
Across 12 randomised trials in 4,862 patients, cricoid pressure did not reduce
Heart & lung : the journal of critical care 2020
The oesophagus already lies lateral to the cricoid in more than half of necks
Anesthesiology 2003
Rapid Sequence Induction (RSI) was used in 82% of patients undergoing tracheal
BMC anesthesiology 2024
Current data are inadequate to mandate either continuing or abandoning cricoid pressure
Anesthesia and analgesia 2021
Across 12 randomised trials in 4,862 patients, cricoid pressure did not reduce
Questions I'll ask you in the room
Walk me through your setup for this before we start.
What are you watching on the monitor that would tell you this is going wrong?
What is your first move if it does?
What would you want ready in the room before induction?
Oral boards stem
A 45-year-old with a small bowel obstruction needs an emergency laparotomy. The resident sets up for a rapid sequence induction and asks whether you want cricoid pressure, and who should apply it.
Board questions
1. An MRI study examined the position of the oesophagus relative to the cricoid and the effect of applying cricoid pressure. Where does the oesophagus lie in most necks at baseline, what does cricoid pressure do to its position, and what happens to the airway?
Show answer
The oesophagus already lies lateral to the cricoid in more than half of necks. Applying cricoid pressure displaces it further sideways, and it also compresses the airway in 81% of subjects.
The anatomy is not on the side of the manoeuvre — in most necks you are pushing a laterally placed oesophagus further aside while narrowing the airway.
Cricoid Pressure Displaces the Esophagus: An Observational Study Using Magnetic Resonance Imaging, Anesthesiology 2003 · PMID 12826843
2. Pooled randomised trials of cricoid pressure during intubation found no reduction in aspiration. Describe the intubation-related harms found in that same pooled analysis, so you can state what you are giving up when you apply it.
Show answer
Across 12 randomised trials in 4,862 patients, cricoid pressure did not reduce aspiration, and it worsened first-attempt success, added nearly 7 seconds to intubation and worsened the laryngoscopic view.
If the manoeuvre does not reduce aspiration but costs you the view, the first attempt and seven seconds, the trade is going the wrong way.
Cricoid Pressure During Intubation: A Systematic Review and Meta-Analysis of Randomised Controlled Trials, Heart & lung : the journal of critical care 2020 · PMID 31685271
3. You have decided to use cricoid force during a rapid sequence induction performed with a videolaryngoscope. Based on modern evidence, what effect should you expect on your ability to intubate, and what two things can improve how the force is applied?
Show answer
Modern evidence suggests cricoid force does not meaningfully impair successful intubation when videolaryngoscopy is used. Where it is applied, it may be improved by ultrasound localisation and by a trained assistant.
If you are going to apply cricoid force, the videolaryngoscope blunts the cost, and who applies it and where matters more than whether you apply it.
4. A resident asks you to give a definitive answer on whether cricoid pressure should be used in the patient at high risk of aspiration. Explain what the current state of the evidence permits you to say, and why you cannot give a categorical answer either way.
Show answer
Current data are inadequate to mandate either continuing or abandoning cricoid pressure, and no universally accepted standard exists for the high-risk aspiration patient. The evidence does not support a categorical instruction in either direction, so the honest answer is that this remains a matter of local practice and individual judgement rather than a settled standard.
Being able to say the evidence does not settle this is a better answer than confidently picking a side that the data cannot support.
The Clinical Use of Cricoid Pressure: First, Do No Harm, Anesthesia and analgesia 2021 · PMID 31397697
The bottom lineAcross 12 randomised trials in 4,862 patients, cricoid pressure did not reduce
Sources
[1] Cricoid Pressure During Intubation: A Systematic Review and Meta-Analysis of Randomised Controlled Trials, Heart & lung : the journal of critical care 2020 · PMID 31685271 open
[2] Cricoid Pressure Displaces the Esophagus: An Observational Study Using Magnetic Resonance Imaging, Anesthesiology 2003 · PMID 12826843 open
[3] Airway Management and Pulmonary Aspiration During Surgical Interventions in Pregnant Women in the 2nd/3rd Trimester and Immediate Postpartum - A Retrospective Study in a Tertiary Care University Hospital, BMC anesthesiology 2024 · PMID 38702641 open
[4] The Clinical Use of Cricoid Pressure: First, Do No Harm, Anesthesia and analgesia 2021 · PMID 31397697 open
[5] Cricoid Pressure May Prevent Insertion of the Laryngeal Mask Airway, British journal of anaesthesia 1992 · PMID 1467077 open
[6] Cricoid Force: Anatomic, Physiologic, and Clinical Concepts, Anesthesiology 2025 · PMID 40923828 open
[7] IRIS trial, cricoid pressure versus sham, JAMA Surg 2019 · PMID 30347104 open
[8] Cricoid pressure and failed intubation RCT, Anesthesiology 2005 · PMID 15681945 open
[9] Effectiveness and risks of cricoid pressure in the ED, Emerg Med Australas 2022 · PMID 35577760 open