Evaluation of Effectiveness of Cricoid Pressure with Ultrasound in Anesthetized Patients: An Observational Study

Abstract

Background: Sellick’s maneuver is a well-known technique of cricoid pressure application that is practiced during rapid sequence induction to prevent regurgitation of gastric contents. The effectiveness of the cricoid pressure application has been often questioned with respect to the success of cricoid pressure application in preventing regurgitation and aspiration. The study aims to measure the outer anteroposterior(A-P) diameter of the esophagus visualized on ultrasound during the application of cricoid pressure in real time to assess its effectiveness.
Methods: 50 inpatients were enrolled as per inclusion and exclusion criteria. After obtaining informed consent, patients were examined with palpation and USG for identification of the cricoid and marked. As per institutional protocol, general anesthesia was induced. After administration of the induction agent, USG was placed over the cricoid in a slight oblique plane, and an uncompressed image of the esophagus was recorded as T1. An anesthesiologist trained in cricoid pressure application applied 30 N cricoid pressure with thumb and index finger. The anesthesiologist was not shown the image of the USG. The image after the application was recorded as T2. The compression was released after the recordings, and the case proceeded as per protocol. The images were analyzed for the anteroposterior diameter of the oesophagus visualized on cross-section, and values were taken.
Results: Appropriate statistical tests were used to obtain mean values of A-P diameter before and after compression. A-P value of 0.05 was considered significant. The oesophagus was visualized in 45/50 (95%) of individuals. In 45 patients, the oesophagus was visualized on the left side of the trachea in the groove behind the thyroid gland and trachea. In 27/45 (60%), there was occlusion of the oesophagus with cricoid pressure application. There was a significant change in the A-P diameter of the oesophageal lumen. In 18/45 (40%), occlusion was not observed.
Conclusion: In our study, the oesophagus as located on the lateral side of the trachea towards left. The cricoid pressure was effective in 60% of cases.