Note to readers: The following piece is a tongue-in-cheek condemnation of the evidentiary base for the use of cricoid pressure for emergency airway management. Cricolol is an imaginary medication, but all of the references quoted below actually refer to cricoid pressure rather than Cricolol. Dr. Hinds uses the artifice of this fabricated drug to demonstrate how poor the evidentiary support is for the use of cricoid pressure for airway management.—SDW

If an assistant’s hand is placed on the patient’s neck, it should be for the sole purpose of assisting with external laryngeal manipulation to allow better glottic exposure.

Recently, I was at the Social Media and Critical Care (SMACC) conference in the Gold Coast of Australia. I looked forward to attending a debate on cricoid pressure for rapid sequence intubation (RSI) in the emergency department and ICU. The speaker was an Irish anaesthetist, intensivist, and prehospital doctor named John Hinds. I looked forward to this lecture because I have always believed the evidence does not support the use of cricoid pressure and that it should not be used for emergency airway management.¹

In an inexplicable turn of events, this lecturer got up and, instead of discussing cricoid pressure, used his allotted time to push a brand-new medication called Cricolol. I still remember Dr. Hinds’ pitch for the drug. It was apparently invented as an herbal remedy by an Irish chap called O’Monroe in 1774, then refined and rebranded by O’Sellick in 1961. O’Sellick performed a nonrandomized trial of just 26 patients in a single hospital.² Even more worrisome for this new medication, there was no standardizing of dose—they just pushed what looked like a good amount. Somehow, based on this, the drug not only got approved, but it was incorporated into national guidelines throughout Ireland. Dr. Hinds indicated that we should be administering it for all of our emergent intubations.

The way Cricolol is administered requires a dedicated and trained assistant to start pushing the medication at the beginning of airway management and continue administration throughout the entire process of securing the airway. The problem is that even though dosing guidelines are included on the package insert, the ampule itself is unmarked and contains variable amounts of drug. When they did postmarketing surveillance, it turns out that the correct dose of the drug was given only 5 percent of the time.³

Aside from that initial small trial, Dr. Hinds tried to convince his audience of the merits of the drug with additional support from BSE data. I’d have to watch the video of the lecture (see below) to remember what that stands for, but I remember the evidentiary level was not very impressive—something about corpses and magnetic resonance imaging (MRI) scanners.

To his credit, Dr. Hinds did admit to some problems with the medication. Cricolol may make airway management more difficult.^4-6 It can prevent endotracheal tube placement once you visualize the cords.⁷ It lowers the esophageal sphincter tone and increases the potential for regurgitation.^8,9 If the medication is dosed too high (a significant risk given the lack of ampule standardization), side effects can include airway fracture and esophageal rupture.^10,11

Dr. Hinds stressed again that the medication must be administered by your trained airway assistant throughout the whole procedure. He wanted to make sure we understood that the assistant’s full attention must be devoted to medication administration at the exclusion of any other assistance during RSI. He did mention that Cricolol will soon be available in suppository form, which may aid administration.

Anticipating audience questions, Dr. Hinds addressed whether it would be reasonable to start administering Cricolol at the beginning of an intubation and, if it made the airway more difficult, we could simply stop administering it. He strongly warned against this plan, explaining that the drug’s creator had the highest incidence of regurgitation ever reported when he used that strategy.

I don’t think I will be pushing for my hospital to add Cricolol to the formulary.

Message Behind the Joke

All kidding aside, Dr. Hinds’ lecture is a must-watch. You can see it at http://emcrit.org/wee/cricolol.

In summary, cricoid pressure, considered an essential aspect of rapid sequence tracheal intubation when it was first conceived, has come under increasing scrutiny within critical care and emergency medicine.¹ Computed tomography and MRI scanning have shown that cricoid pressure causes tracheal compression in 80 percent of patients. Numerous studies have found that cricoid pressure hinders bag-valve-mask device ventilation, increases peak inspiratory pressure, and reduces tidal volumes.1 For the same reasons that the airway obstruction induced by cricoid pressure may preclude effective manual ventilation, it may limit the effectiveness of apneic oxygenation as well. If an assistant’s hand is placed on the patient’s neck, it should be for the sole purpose of assisting with external laryngeal manipulation to allow better glottic exposure.^7,12

I do not believe in the use of cricoid pressure for RSI for all of the reasons mentioned above. However, I don’t think you should make this call as an individual doc but instead make a departmental guideline stating that, after a review of the evidence, cricoid pressure seems not helpful and possibly harmful. This will protect all members of your department while allowing excellent patient care.

Dr. Weingart is an ED intensivist. This column is a distillation of the best material from the EMCrit Blog and Podcast (http://emcrit.org).

Dr. Hinds is an intensivist and an Irish Road Racing Doctor. Follow him on twitter @DocJohnHinds..

References

1. Weingart SD, Levitan RM. Preoxygenation and prevention of desaturation during emergency airway management. Ann Emerg Med. 2012;59:165-75 e1.
2. Sellick BA. Cricoid pressure to control regurgitation of stomach contents during induction of anaesthesia. Lancet. 1961;2:404-6.
3. Koziol CA, Cuddeford JD, Moos DD. Assessing the force generated with application of cricoid pressure. AORN J. 2000;72:1018-1028, 1030.
4. Smith KJ, Dobranowski J, Yip G, et al. Cricoid pressure displaces the esophagus: an observational study using magnetic resonance imaging. Anesthesiol. 2003;99:60-4.
5. Hartsilver EL, Vanner RG. Airway obstruction with cricoid pressure. Anaesth. 2000;55:208-11.
6. Allman KG. The effect of cricoid pressure application on airway patency. J Clin Anesth. 1995;7:197-9.
7. Levitan RM, Kinkle WC, Levin WJ, et al. Laryngeal view during laryngoscopy: a randomized trial comparing cricoid pressure, backward-upward-rightward pressure, and bimanual laryngoscopy. Ann Emerg Med. 2006;47:548-55.
8. Garrard A, Campbell AE, Turley A, et al. The effect of mechanically-induced cricoid force on lower oesophageal sphincter pressure in anaesthetised patients. Anaesth. 2004;59:435-9.
9. Chassard D, Tournadre JP, Berrada KR, et al. Cricoid pressure decreases lower oesophageal sphincter tone in anaesthetized pigs. Can J Anaesth. 1996;43:414-7.
10. Heath KJ, Palmer M, Fletcher SJ. Fracture of the cricoid cartilage after Sellick’s manoeuvre. Br J Anaesth. 1996;76:877-8.
11. Ralph SJ, Wareham CA. Rupture of the oesophagus during cricoid pressure. Anaesth. 1991;46:40-1.
12. Hwang J, Park S, Huh J, et al. Optimal external laryngeal manipulation: modified bimanual laryngoscopy. Am J Emerg Med. 2013;31:32-6.