The effects of cricoid pressure, remifentanil, and propofol on esophageal motility and the lower esophageal sphincter.

Cricoid pressure is the gold standard during the induction of anesthesia when there is a risk of aspiration of gastric contents. However, the effect of cricoid pressure during the different steps of complete anesthesia induction has not been studied. The purpose of this study was to investigate the effects of cricoid pressure, remifentanil, and propofol on lower esophageal sphincter (LES) and esophageal motility. We recorded LES pressure (LESP) and calculated barrier pressure ([BrP] = LESP - gastric pressure) in 10 healthy volunteers using a Dent sleeve device. There was a significant decrease in LESP and BrP when a cricoid pressure of 30 N was performed in the awake volunteers (P < 0.05). However, this effect was not seen during the infusion of remifentanil 0.2 microg . kg(-1) . min(-1). Remifentanil per se or together with a bolus dose of propofol 1 mg/kg IV did not induce any statistical change in LESP or BrP. Remifentanil abolished spontaneous esophageal motility and completely eliminated the experience of discomfort induced by cricoid pressure. In conclusion, cricoid pressure of 30 N induced a decrease of LESP and BrP in awake volunteers. These effects were not seen during the remifentanil infusion. This shows the importance of when to apply cricoid pressure during rapid-sequence induction.