Rapid sequence induction: evidence, opinion and the cricoid question

What the paper says

This narrative review from an experienced UK group examines the evidence behind each component of rapid sequence induction (RSI). It was prompted in part by coroners' concerns after deaths from aspiration. Its central message is that RSI is widely used, but most of its components rest on limited evidence. It should therefore be applied with a clear understanding of where the evidence is strong, where it is weak and where it is absent.

The review covers nasogastric tubes, pre-oxygenation and apnoeic oxygenation, induction drugs, total intravenous anaesthesia, cricoid force, facemask ventilation, videolaryngoscopy, rescue with a supraglottic airway, cardiovascular compromise, awareness and gastric ultrasound. It closes with a welcome emphasis on individualised risk assessment, illustrated by a patient whose balance of risks shifts with the urgency of surgery, frailty and previous airway difficulty.

What is well supported by evidence

• Videolaryngoscopy improves first-attempt success during RSI and should be routine.
• Non-invasive ventilation and high-flow nasal oxygen improve pre-oxygenation, particularly in critically ill patients.
• Cardiovascular complications are common in critically ill patients, and propofol is associated with more instability than alternatives.
• A nasogastric tube does not reliably empty the stomach.
• Cricoid force impedes supraglottic airway insertion and should be released for rescue.
• Training and real-time feedback improve the accuracy of cricoid force.

What remains controversial

• Whether cricoid force reduces harm from aspiration.
• How to interpret the IRIS trial.
• Whether paratracheal force is a better alternative to cricoid force.
• Ketamine versus etomidate in critically ill patients.
• The role of total intravenous anaesthesia during RSI.
• How gastric ultrasound and GLP-1 receptor agonists should change practice.

What is largely expert opinion

Several of the review's practical recommendations are reasoned positions rather than evidence-based conclusions. They include:

• the 30 N target for cricoid force, which rests on manometry and cadaver work rather than patient outcomes;
• leaving a nasogastric tube on free drainage;
• maintaining cricoid force if regurgitation occurs after loss of consciousness;
• undertaking RSI in theatre rather than the anaesthetic room;
• avoiding propofol with remifentanil in frail patients, which derives from associations in NAP7;
• the statement that correct application of cricoid force is easily taught, which sits uneasily with the review's own evidence that it is usually applied incorrectly.

These positions may well be sensible. However, readers should recognise them as the authors' informed judgement. It is also fair to note that the cricoid force section draws substantially on the authors' own long-standing body of work.

My commentary

The cricoid force section is the heart of the review, and it is where I would encourage readers to look beyond the UK perspective.

Internationally, the evidence is consistent. In the IRIS trial of 3,472 patients, aspiration occurred in 0.6% with cricoid pressure and 0.5% with a sham, while grade 3–4 laryngoscopy views doubled.² A meta-analysis of 12 randomised trials found no difference in aspiration, with worse first-attempt success, worse laryngoscopic views and longer time to intubation.³ An Australian emergency department trial found that ideal cricoid force could not be maintained during laryngoscopy, and that a quarter of patients had laryngeal contamination despite it.⁴ Across Europe, more than a third of anaesthetists never use cricoid pressure at all.⁵ None of these studies demonstrates harm from omitting it. The authors are right that this is not proof of no benefit in the highest-risk patients. However, it is equally not evidence that cricoid pressure is essential.

So why do most anaesthetists in Australia and New Zealand continue to use it routinely? In a survey of ANZCA Fellows, 77% reported routine use, yet only 40% believed it reduced regurgitation. Sixty per cent of routine users cited fear of the medicolegal consequences of omitting it as a main reason.⁶ I understand why. If a patient aspirates and cricoid pressure was not applied, the case review is likely to focus on that single omission. A certain kind of expert witness will explain, with great confidence, that the outcome was therefore entirely the anaesthetist's fault. I am being slightly facetious, but the underlying problem is real. Hindsight fixes on the endpoint and its most visible missing component, rather than on the decisions that preceded it.

Those preceding decisions usually matter far more. Was the risk of aspiration assessed and documented? Was RSI the right choice for this patient, or was an awake or regional technique more appropriate? Was the stomach decompressed where indicated? Was the patient adequately anaesthetised and paralysed before laryngoscopy? Was the first attempt the best attempt? Was the team prepared and the plan communicated? Cricoid pressure is easy to document. Good judgement is not.

The review's own conclusion points the way: individualised risk assessment, clear decision-making and good technique. Whether cricoid pressure is applied or omitted, the decision should be deliberate, explained to the patient where possible and recorded with its reasoning. A reasoned decision is far easier to defend than an unthinking ritual, whichever way it goes.

References

1. Cook TM, Plaat F, McNarry AF, Barclay P, Vanner R. Rapid sequence induction: a narrative review. Anaesthesia 2026. doi:10.1111/anae.70449
2. Birenbaum A, Hajage D, Roche S, et al. 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: 9–17. doi:10.1001/jamasurg.2018.3577
3. White L, Thang C, Hodsdon A, Melhuish T, Vlok R. Cricoid pressure during intubation: a systematic review and meta-analysis of randomised controlled trials. Heart Lung 2020; 49: 175–80. doi:10.1016/j.hrtlng.2019.10.001
4. Trethewy CE, Doherty SR, Burrows JM, Clausen D. Ideal cricoid pressure is biomechanically impossible during laryngoscopy. Acad Emerg Med 2018; 25: 94–8. doi:10.1111/acem.13326
5. Klucka J, Kosinova M, Zacharowski K, et al. Rapid sequence induction: an international survey. Eur J Anaesthesiol 2020; 37: 435–42. doi:10.1097/EJA.0000000000001194
6. Mistry R, Frei DR, Badenhorst C, Broadbent J. A survey of self-reported use of cricoid pressure amongst Australian and New Zealand anaesthetists: attitudes and practice. Anaesth Intensive Care 2021; 49: 62–9. doi:10.1177/0310057X20968841

This commentary is my own professional opinion, written for anaesthetists and other professional readers. It does not represent Alfred Health, ANZCA or any other organisation with which I am associated, and it is not individual medical advice. The original article is the work of its authors and is linked above.