Using Ultrasonography to Assess the Effectiveness of Cricoid Pressure on Esophageal Compression

Cricoid pressure during intubation has been used for decades as a way to potentially occlude the esophagus to avoid aspiration of gastric contents. However, recent evidence has questioned the effectiveness of this maneuver.

This study uses a noninvasive modality, ultrasonography, to determine the anatomic position of the cricoid cartilage and the esophagus and examines the effectiveness of cricoid pressure on esophageal compression.

Ultrasound imaging was used to describe the anatomic relationship of the esophagus to the trachea as either being directly behind the trachea, partially behind the trachea, or completely lateral to the trachea. These relationships were described with and without cricoid pressure. Participants were also asked to swallow a carbonated beverage with and without cricoid pressure to help visualize the exact position of the esophagus and to see whether cricoid pressure actually occluded the esophagus and the passage of the liquid.

Without cricoid pressure, 20% of the esophagi laid directly behind the trachea, 60% partially behind the trachea, and 20% completely lateral to the left of the trachea. When cricoid pressure was applied, the esophagus shifted laterally to the left in 50% of the subjects and remained directly behind the trachea in only 4% of our entire study group. In addition, all of the participants were able to swallow liquid with cricoid pressure applied.

This study highlights the potential ineffectiveness of cricoid pressure on esophageal compression, calling into question the utility of this maneuver.