Esophageal Preparation

In the warm water preparation group, the patients drank 1 L of warm water at 60℃ during 30 minutes at 8 PM the day before the POEM. Moreover, the patient had nothing to eat or drink after midnight the evening before the procedure in both the warm water preparation group and the control group.

The degree of clearness of the esophagus was compared with that of the control cohort, in which the patients underwent endoscopic procedures without warm water preparation. We defined the esophageal clearness scale for assessment of esophageal preparation quality (Table 1). Grades 0 to 3 were defined as follows: 0 = the entire mucosa of the esophagus can be clearly observed without residual staining; 1 = minor amount of residual staining with opaque liquid can be observed, but the entire esophageal mucosa can be easily observed just by endoscopic suction; 2 = a portion of the mucosa of the esophagus can be observed, but residual solid food retention hinders the observation of the entire esophageal mucosa; and 3 = an unprepared esophagus with the mucosa cannot be observed due to large quantity of solid retention that cannot be cleared by endoscopic suction.

Esophageal Clearness Grade

Figure shows the representative endoscopic images of each esophageal clearness scale. Grades 0 and 1 indicate that the quality of preparation is good, which is a state adequate for endoscopic therapeutic procedures. Grades 2 and 3 indicate that the quality of preparation is poor, which is a state inadequate for endoscopic therapeutic procedures.

Representative case of different endoscopic preparation grades for patients with achalasia.