Measurement of intragastric pressure: an objective method to ascertain whether gastric wall extension is sufficient for assessment of the non-extension sign

Background and study aims The optimal intragastric pressure (IP) for strong gastric wall extension is unclear. We aimed to develop an accurate method to measure IP using endoscopy and determine the pressure required for strong gastric wall extension. Methods An in vitro experiment using an endoscope with a rubber attached at its tip was conducted. The process of inserting the pressure measurement probe into the forceps channel was skipped, and the tube of the pressure measurement device was directly connected to the forceps channel. In vivo, the pressure in 51 consecutive patients at the time of strong gastric wall extension was measured. Strong extension of the gastric wall was defined as when the folds in the greater curvature were flattened as a result of sufficient extension of the gastric wall by insufflated air during upper gastrointestinal endoscopy. The IP at that time was measured. Results In vitr o , 20 mL of tap water was injected once into the forceps channel and then aspirated for 10 seconds. Pressure measurement after irrigation of the forceps channel as well as the measurement by inserting the probe procedure were accurately performed. In vivo, among the 51 included patients, the mean IP (range) was 14.7 mmHg (10–23). Strong extension of the gastric wall was obtained in 96.1 % of patients when the IP was 20 mmHg. Conclusions We developed an accurate method to measure IP using upper gastrointestinal endoscopy. Strong extension of the gastric wall was obtained in almost all patients when the IP was 20 mmHg.