cricoid pressure. friend or foe?
By impactEDnurse • Mar 27th, 2008 • Category: clinical skills, the nurses desk:, tips and tricks
Photo credit: Hamed Saber
Cricoid pressure is the application of a compressive force over the cricoid cartilage with the aim of squashing closed the esophagus against the underlying vertebrae. It is performed during rapid sequence intubation to prevent the unconscious patient regurgitating their gastric contents into:
a) their oropharynx making intubation extremely difficult.
b) their lungs ( aspiration) making breathing extremely difficult.
Cricoid pressure has been a mandatory step in the intubation process ever since Dr Sellick first demonstrated its occluding properties on cadavers in 1961.
But recently questions have been asked regarding the actual efficacy of the practice. What is the evidence that cricoid pressure protects the patients airway?
A risk-benefit analysis conducted after reviewing around 700 journal articles and reported in Annals of Emergency Medicine concluded that in fact cricoid pressure often reduces airway patency and worsens the view of the airway for the intubating doctor…..
Protecting against aspiration.
Although teaching the application of cricoid pressure is widespread, the actual technique including anatomical positioning of the fingers, and amount of pressure applied varies greatly between medical staff. In fact there many many cases reported of aspiration occurring despite the application of pressure. There are even 3 case reports of fatal regurgitation and aspiration.
Some studies have shown that cricoid pressure may reduce the pressure in the lower oesophagus ( known as the barrier pressure ) leading to increased gastric distension as air leaks into the stomach during bag-valve-mask ventilation of the patient prior to intubation.
Gastric distension increases the risk of regurgitation.
Obstructing the airway.
10 articles reviewed all reported reduced tidal volumes, increased peak pressures and airway obstruction during bag-valve-mask ventilation. There were 2 reports of complete airway obstruction.
Obstructing view of the airway.
There are mixed findings, but quite a few reports of a worse laryngeal view with cricoid pressure applied leading to a difficult or impossible intubation.
Findings seem to indicate that doctors, nurses and other medical staff are universally inconsistent at providing optimum cricoid pressure.
Trauma to the airway.
There have been reports of trauma caused by pressure to the cricoid cartilage including ruptured oesophagus, and fractured cartilage.
So, friend or foe?
Well, don’t start refusing to perform cricoid pressure just yet.
With proper technique and attention to application of pressure, it may still offer useful protection. However this is just another example of the need for nurses to question the evidence and the quality in everything we do. And the importance in evidence based research projects.
The authors conclude:
Cricoid pressure entered medical practice on a limited evidence base but with common sense supporting its use. Given that the risks of cricoid pressure worsening laryngeal view and reducing airway patency have been well described, we recommend that the removal of cricoid pressure be an immediate consideration if there is any difficulty either intubating or ventilating the ED patient.
Hat tip to Dr Hall for the article.
impactEDnurse is also known as Ian Miller, a nurse with over 26 years experience working in a busy emergency department in, Australia. This site in no way reflects the opinions of that hospital.
All stories (although based on actual experiences) have been changed to protect patient confidentiality.
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Actually, judicious use of BURP (back, up, right, pressure) can be really helpful for visualisation depending on the patient, though in my experience (non-ED admittedly though you have to do RSI on some patients in the OR) the nurses here tend to wait until you ask for cricoid pressure which is also great.
I was informed somewhere in my distant past, that the optimal cricoid pressure is 20 Newtons which, appartently, is equivalent to the (downward) pressure required to reduce your weight by 2kg if standing on scales. (Not recommended to trying in the middle of an RSI – “wait a moment I just need to get my scales”)
I am willing to be shot down mercelessly if this is incorrect, however if it is correct it may be a better example of appropriate pressure compared to other suggestions, such as ‘the pressure equal to that which would cause discomfort on the bridge of your nose’, which is possibly more likely to be more variable between individuals, however noses are more readily availible to the average person during a discussion on cricoid pressure.
If an injury to the cricoid, such as a blow to the trachea, should cause the cartilage to swell, what would happen to the victim?
If an injury to the cricoid, such as a blow to the trachea, should cause the cartilage to swell, what would happen to the victim? For instance, will the cricoid cartilage grandually swell, ultimately causing death by asphyxiation? And, if an autopsy is performed on the victim, will there be signs to prove swelling had occurred prior to death?