The lower esophageal sphincter（LES）plays a key role in preventing regurgitation and aspiration. The pressure of LES partly comes from striated muscles derived from the crural portion of the diaphragm. The effect of succinylcholine on esophagogastric junction during anesthesia induction is not clear. We conducted a prospective interventional study on the effect of succinylcholine on the barrier pressure (BrP) of the esophagogastric junction.

14 patients participated in the study. Propofol and succinylcholine were used for anesthesia induction. High-resolution solid-state manometry (HRM) was used to monitor the changes of the LES pressure and the intragastric pressure (IGP).The administration of propofol could significantly increase the LES pressure during end expiration and during inspiration. The application of succinylcholine had no effect on the LES pressure during end expiration, but significantly reduced the LES pressure during inspiration. Propofol had no effect on BrP. After the application of succinylcholine, BrP decreased significantly during inspiration.

Propofol significantly increased the LES pressure. Succinylcholine significantly reduced the pressure of LES and BrP during inspiration.

Exclusion criteria：patients who classified as American Society of Anesthesiologists classification system (ASA) II were included. Patients were included in the study if they had on history of diabetes, pharynx and digestive diseases.

Exclusion criteria：currently pregnant or breastfeeding, a body mass index (BMI) over 30 kg/m2. All patients underwent preoperative preparation according to clinical routine and did not give preoperative drugs.