Atraumatic non-distorting pyloric sphincter pressure studies.

Conflicting claims have been made regarding the physiological characteristics of the pyloric sphincter. Pyloric sphincter pressures were studied in 32 patients under basal conditions, after stimulation with HCl and posture changes. At gastroscopy a 2 mm diameter manometer catheter was placed in the duodenum and three to five hours later the catheter was withdrawn slowly with continuous manometry. Lower esophageal sphincter pressures fell within the expected range but there was no definite evidence of a pressure barrier at the pylorus in any group of patients. The technique caused no patient discomfort and minimal distortion of the region under study, indicating that the pylorus is usually patent with a lumenal diameter greater than 2 mm.