EMS Medical Terminology - Sellick's Maneuver

EMS providers should be familiar with the Sellick Maneuver, also known as cricoid pressure, as a technique designed to reduce the risk of regurgitation and aspiration during endotracheal intubation, particularly in patients who are not fasting or at high risk of vomiting. It is an example of an eponymous medical term.

It was first described by Dr. Brian Sellick in 1961 and has been used in emergency and anesthetic situations ever since. 

However, it’s essential for EMS providers to apply the right amount of pressure and know that this technique is sometimes debated due to concerns that it may obstruct the airway or complicate intubation in some cases.

Here's what they should know:

Key Concepts

Anatomy Involved:

The cricoid cartilage is a ring-shaped structure located just below the thyroid cartilage in the neck.

When performing the Sellick Maneuver, downward pressure is applied to the cricoid cartilage, which in turn compresses the esophagus against the vertebral column, theoretically reducing the chance of regurgitation by preventing stomach contents from moving into the pharynx.

When to Use It:

Primarily used during rapid sequence intubation (RSI) to protect the airway in emergency situations, especially when there's a high risk of vomiting (e.g., trauma patients, those who have recently eaten, or have decreased consciousness).

It may also be employed during bag-valve-mask (BVM) ventilation to prevent gastric insufflation, although this use is somewhat controversial.

How to Perform It:

The provider places firm, continuous pressure using the thumb and forefinger on the cricoid cartilage (located below the Adam’s apple).

The recommended pressure is about 10 Newtons (≈1 kg of force) initially, increasing to 30-40 Newtons (≈3-4 kg of force) once the patient loses consciousness, as the risk of vomiting increases at that point.

Controversies & Limitations:

Questionable Efficacy: Studies over the years have raised doubts about the effectiveness of the Sellick Maneuver in completely preventing regurgitation or aspiration. In some cases, it may even impair ventilation or visualization of the airway during intubation, particularly in difficult airway scenarios.

Potential Complications: Incorrect application of the maneuver (too much force or misplacement of pressure) can result in airway obstruction or displacement of the esophagus laterally rather than compressing it.

Many modern airway protocols have deemphasized its routine use and instead focus on optimal intubation techniques and preparation for managing airway complications.

Training & Clinical Judgment:

EMS providers should be well-trained in applying the maneuver correctly, but also be aware that if it interferes with ventilation or intubation, it should be discontinued.

It’s essential to assess the specific patient scenario (e.g., suspected difficult airway) and weigh the benefits and risks of applying cricoid pressure.

Summary

The Sellick Maneuver was historically considered a key technique for preventing aspiration during emergency intubation, but its effectiveness is now debated. 

EMS providers should understand the anatomy, application method, and potential complications, and apply it judiciously based on the clinical situation.

Further Reading:

Alexander, M. & Belle, R. (2017) Advanced EMT: A Clinical Reasoning Approach (2nd Ed). Hoboken, New Jersey: Pearson Education

Bledsoe, B. E., Cherry, R. A. & Porter, R. S (2023) Paramedic Care: Principles and Practice (6th Ed) Boston, Massachusetts: Pearson

Brown, C. A. (2022) Walls Manual of Emergency Airway Management (5th Ed). Philadelphia, Pennsylvania: Lippincott, Williams & Wilkins.

Ebright, C. (2024) Unique Patient Signs: A Case Study. EMS1. Accessed May 1, 2024

Mistovich, J. J. & Karren, K. J. (2014) Prehospital Emergency Care (11th Ed). Hoboken, New Jersey: Pearson Education

Peate, I. & Sawyer, S (2024) Fundamentals of Applied Pathophysiology for Paramedics. Hoboken, New Jersey:  Wiley Blackwell