title: Effects of cricoid pressure and remifentanil on the esophageal sphincters using high-resolution solid-state manometry.
abstract: BACKGROUND
  Cricoid pressure has been shown to decrease the pressure in the lower esophageal sphincter (LES), increasing the risk of aspiration. Whether this reaction is due to pain associated with the application of cricoid pressure has not been studied. The aim of this study was to compare the effects of cricoid pressure with those of peripheral pain on pressures in the LES, and to study whether remifentanil influences these effects. Data from the upper esophageal sphincter (UES) are also described.
  
  
  METHODS
  Continuous solid-state manometry was performed in 14 healthy volunteers. Initially, the effect of remifentanil (target-controlled infusion with a plasma target concentration of 5.0 ng/ml) was studied, and thereafter, the effects of cricoid pressure and peripheral pain stimulation (cold stimulation). Finally, these two interventions were repeated under ongoing remifentanil infusion.
  
  
  RESULTS
  Remifentanil decreased the LES pressure significantly [ΔP-6.5 mmHg, 95% confidence interval (95% CI) -1.7 to -11.2]. Cricoid pressure application decreased the LES pressure significantly (ΔP-3.7 mmHg, 95% CI -1.4 to 6.1), whereas peripheral pain did not (ΔP 1.2 mmHg, 95% CI -3.5 to 1.1). Under ongoing remifentanil infusion, no cricoid pressure-induced LES relaxation was observed. Cricoid pressure induced high pressures in the area of the UES, 215.7 (±91.2) mmHg without remifentanil vs. 219.4 (±74.2) mmHg with remifentanil.
  
  
  CONCLUSIONS
  Remifentanil as well as cricoid pressure per se induced decreases in LES pressure. However, cricoid pressure-induced changes of the barrier pressure were not significant whether induced with or without an infusion of remifentanil.
authors.affiliation: Department of Anesthesiology and Intensive Care, Örebro University Hospital, Sweden. rebecca.ahlstrand@orebroll.se
authors.forename: R
authors.initials: R
authors.lastname: Ahlstrand
authors.forename: J
authors.initials: J
authors.lastname: Savilampi
authors.forename: S-E
authors.initials: SE
authors.lastname: Thörn
authors.forename: M
authors.initials: M
authors.lastname: Wattwil
mesh_terms: D000293:Adolescent; D000328:Adult; D001784:Blood Gas Analysis; D003080:Cold Temperature; D003413:Cricoid Cartilage / Q000502:physiology*; D049630:Esophageal Sphincter, Lower / Q000187:drug effects / Q000502:physiology*; D049631:Esophageal Sphincter, Upper / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D008365:Manometry / Q000379:methods*; D010146:Pain / Q000503:physiopathology; D010880:Piperidines / Q000494:pharmacology*; D011312:Pressure; D000077208:Remifentanil; D055815:Young Adult
chemical_list: D006993:Hypnotics and Sedatives; D010880:Piperidines; D000077208:Remifentanil