Ultrasound Assessment of the Effectiveness of Cricoid Pressure

Background and Aims- The application of cricoid pressure (CP) during rapid sequence induction to prevent regurgitation of gastric contents has been questioned by many studies in the past decade. There is a paucity of randomised controlled trials (RCTs) to support or to refute the application of cricoid pressure. We used real time ultrasound in this study to evaluate the location of oesophagus and its displacement on application of cricoid pressure. Methods- Thirty two healthy volunteers underwent ultrasound examination of the neck with and without CP. The location of oesophagus (measured as distance from mid-cricoid to mid-oesophagus), its displacement with cricoid pressure (measured from mid-cricoid to mid-oesophagus after cricoid pressure) were measured. The subjective assessment of difficulty in swallowing on cricoid pressure was also noted. Results -The oesophagus was located on the left side of the cricoid in all the patients. The mean (SD) distance from mid-cricoid to mid-oesophagus without CP as well as with CP was 1.10 (0.25) cm and 1.04 (0.46) cm respectively, which was statistically not significant. The mean (SD) antero-posterior diameter of the oesophagus without as well as with CP was 0.67 (0.39) and 0.40 (0.04) cm respectively, which was statistically significant (p=0.001). Half of the participants reported difficulty during swallowing with CP. Conclusion- In our study, we observed that application of CP did not displace the oesophagus significantly from its neutral position but effectively reduced its antero-posterior diameter which was significant. This shows that CP is useful and effective in occluding the oesophagus even when it is located away from the mid-line and displaced with CP.