NAP4 responds on cricoid pressure

Some joker on Twitter called Chrimes took this at Aspen, Colorado
Some joker on Twitter called Chrimes took this at Aspen, Colorado

Hi folks. Over Easter there was a bit of a chat on FOAMEd forums about cricoid pressure. Someone suggested I contact the NAP4 editors and ask for their comment on this issue. So I did.

Firstly NAP4 is widely regarded as one of the most important publications in recent years on emergency airway management in the UK.

I have permission from the editors who I communicated with to publish their statement.

The NAP4 editors who collectively responded to my question are : T Cook, N Woodall and C Frerk

Dr Tim Cook
Consultant Anaesthetist
Royal United Hospital, Bath
Joint Lead for the 4th National Anaesthesia Audit

Dr Nick Woodall
Co-Audit Lead, 4th National Audit Project (NAP4)

Dr Chris Frerk
Consultant Anaesthetist
Northampton General Hospital, Northampton


Okay what follows now is my original email and then their response.

Dear editors of the NAP4 publication

I am a prehospital and retrieval medicine doctor with the Royal Flying Doctor Service of Australia.
I also run a medical blog,
Lately my colleagues and I have been having a debate about the role of cricoid pressure in rapid sequence intubation in the prehospital and ED settings
We often cite the NAP4 as a reference work in regard to its recommendation to use cricoid pressure as standard of care in RSI.
Here is a recent post on a colleagues blog site, describing the opposition to use of cricoid pressure
I was wondering if you  would comment on this debate and whether you still believe cricoid pressure is the standard of care for RSI?
thanks for helping if you can
Dr Minh Le Cong
RFDS Cairns and Mt Isa, Queensland, Australia
Dr Nick Woodall responded on their behalf:

Hi Dr Le Cong,

We have discussed the issue of cricoid pressure and the NAP4 report. I hope you will find our views helpful.
The NAP4 report does not specifically endorse cricoid force though as it does support the need for rapid sequence induction (RSI) this is largely implied. Aspiration accounted for more than half of anaesthesia cases
resulting in deaths or brain damage. Amongst the contributory factors identified in review of these cases was a failure to use recognised techniques designed to lessen the risk of aspiration when risk factors existed. Amongst those recognised techniques would be RSI. In the UK RSI is generally taken to include the use of cricoid force.

We did emphasise that where cricoid force is employed it should be performed by those who are trained and practiced in it.

Correctly applied cricoid force is unlikely to worsen view at laryngoscopy and may even improve it. It should not impede mask ventilation (but may reduce gastric inflation). Incorrectly applied cricoid force leads to
difficult laryngoscopy, airway obstruction and a risk of failed mask ventilation.

The editorial by Vanner and Asai (Anaesthesia 1999) remains one of the best pieces of writing on the topic and is recommended reading. It recommends use of cricoid pressure (3kg) as a component of RSI.  If direct laryngoscopy is difficult it recommends reducing then releasing cricoid pressure whilst simultaneously performing direct laryngoscopy with a suction catheter in hand to deal with regurgitation should this occur. These methods seek to maximise the potential benefits of this manoeuvre whilst minimising the potential hazards.

One important additional comment is that videolaryngoscopy has a potentially important role in RSI. VL – with a remote screen- enables all those involved in the induction (anaesthetist, assistant and others) to see the ease of laryngoscopy, the view of laryngoscopy and the impact of cricoid force. It is likely that use of VL at RSI improves teamwork – but again published evidence of that we believe is lacking.

In NAP4 we stated
NAP 4 has identified several cases where the omission of RSI , although there were strong indications for its use, was followed by patient harm, or death from aspiration. There were no cases where cricoid force was reported to lead to major complications. Rapid sequence induction with cricoid force does not provide 100% protection against regurgitation and aspiration of gastric contents, but remains the standard for those patients at risk. Recommendation: On balance, rapid sequence induction should continue to be taught as a standard technique for protection of the airway. Further focused research might usefully be performed to explore its efficacy, limitations and also explore the consequences of its omission.


Nick Woodall

11 thoughts on “NAP4 responds on cricoid pressure

  1. A beautiful if not political response.

    Q: should we use cricoid pressure?
    A: yes, you should use RSI to prevent aspiration
    Q: but what about Crico-
    A: yes RSI is good. Thank you.

    Thank you Minh for going the extra mile for #FOAMed !

  2. thanks Minh for advancing this. Sounds like NAP4 authors are primarily advocates of RSI which no one here would disagree with. They seem a bit softer on cricoid though supportive of it. However I dispute their facts and this assumption that only improperly applied cricoid can cause problems. Certainly properly applied cricoid can cause issues and that’s leaving aside the lack of a firm evidence base about what actually is “proper application”. Also this idea of using cricoid and removing it if in trouble does not take into account that Cricoid lowers LOS pressure so applying and releasing it may actually increase regurg and aspiration risk compared with not applying at all.
    In any case sounds like the NAP4 guys can only suggest with any confidence that the failure to use RSI was the problem in their audit not the failure to use cricoid.
    Also interested to hear Cliff’s response on this.

    1. thanks Anand. 2 RCT are underway , one in France the other in NSW. we shall see. About the LOS lowering..yes this has been demonstrated but its not a patient orientated outcome. 2014 study shows video laryngoscopic evidence of inability to pass NGT when 30N cricoid force applied. It maybe irrelevant what is occurring in LOS lower down.
      As Karim Brohi tweeted on this, lack of evidence does not always mean lack of benefit and rather than discard things , it maybe better to await research and more training.

  3. This is a debate that I have followed closely, and participated in frequently in our local setting. There are a lot of misconceptions. As an anaesthetist with a particular focus on airways performing multiple forms of airway management in high risk patients every day, I am fairly convinced of the value of cricoid force when correctly applied in the right setting. As a lifelong EM junkie and prehospital medic, I recognize the necessity to question the dogma that surrounds what we do and practice ‘lean medicine’.

    Without rehashing the entire debate, I do want to stress two things:

    1). When anaesthetists talk about RSI, it expressly INCLUDES using cricoid force, as this is a part of the definition of RSI from our perspective. However, we tend to have skilled and trained assistance at all times, making the correct use much simpler.

    2). The LOS argument against cricoid force is probably moot in the light of the fact that just about all the drugs we may use for (and preceding) RSI directly decrease LOS tone, regardless of whether we are providing cricoid force. This includes benzos, opiates, paralytics and all the induction agents with to the significant exception of ketamine. Passive regurgitation into the lower oesophagus is common and inconsequential, provided it does not traverse the UOS – herein lies the rub.

    I think we are going to have quite a bit more discourse on the subject over time, and should be keeping an open mind. In the meantime, cricoid force costs me nothing, seldom makes my life for difficult, is immediately reversible and may be helping my patients. YMMV.

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