In the most recent edition of 'Continuing Education in Anaesthesia, Critical Care and Pain' there is a very good overview article on rapid sequence induction (RSI) and its place in modern anaesthesia. Wallace and McGuire also critically look at cricoid pressure (CP) as a part of classical RSI.
In their publication they state that "there have been no prospective randomized clinical studies performed to prove the clinical hypothesis and the level of evidence to support the use of cricoid pressure is poor (Level 5)". Level 5 corresponds to 'Expert Opinion' (see table below). They also mention that aspiration has occured despite CP, that CP is often poorly performed, that it may hinder bag-valve mask ventilation as well as LMA insertion and that is may worsen laryngoscopy. It's mentioned that "Critically, it has also been shown to potentially obstruct the upper airway and reduce time to desaturation".
'This is nothing new' you might say. Why am I mentioning this? Well, the remarkable thing about this article is the fact that it was published in a Journal that is a joint venture of the British Journal of Anaesthesia BJA and The Royal College of Anaesthetists in collaboration with the Intensive Care Society and Pain Society. Considering the fact that The NAP4 guidelines continue to support its use as part of an RSI and as such, it is still considered a standard of care in the UK and therefore also Ireland, this publication might indicate some change in mind... or not?
The authors summarize: Application of cricoid pressure is advisable — unless it obscures the view at laryngoscopy or interferes with manual ventilation or supraglottic airway device placement.
I personally still would want to know what exactly makes a 'Level 5' medical intervention 'advisable' especially in regards of all the possible problems and complications associated with it.
Wallace et al., Continuing Education in Anaesthesia, Critical Care & Pain, Volume 14(3), June 2014, p 130–135
Read our previous BIJC post: Cricoid Pressure for RSI in the ICU: Time to Let Go? (Updated)